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freebsd-skq/sys/dev/hwpmc/hwpmc_mod.c
Joseph Koshy 6fe00c7876 - Bug fix: prevent a thread from migrating between CPUs between the 
time it is marked for user space callchain capture in the NMI
  handler and the time the callchain capture callback runs.

- Improve code and control flow clarity by invoking hwpmc(4)'s user
  space callchain capture callback directly from low-level code.

Reviewed by:	jhb (kern/subr_trap.c)
Testing (various patch revisions): gnn,
		Fabien Thomas <fabien dot thomas at netasq dot com>,
		Artem Belevich <artemb at gmail dot com>
2008-12-13 13:07:12 +00:00

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/*-
* Copyright (c) 2003-2008 Joseph Koshy
* Copyright (c) 2007 The FreeBSD Foundation
* All rights reserved.
*
* Portions of this software were developed by A. Joseph Koshy under
* sponsorship from the FreeBSD Foundation and Google, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/eventhandler.h>
#include <sys/jail.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/pmc.h>
#include <sys/pmckern.h>
#include <sys/pmclog.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/queue.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/signalvar.h>
#include <sys/smp.h>
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>
#include <sys/systm.h>
#include <sys/vnode.h>
#include <sys/linker.h> /* needs to be after <sys/malloc.h> */
#include <machine/atomic.h>
#include <machine/md_var.h>
/*
* Types
*/
enum pmc_flags {
PMC_FLAG_NONE = 0x00, /* do nothing */
PMC_FLAG_REMOVE = 0x01, /* atomically remove entry from hash */
PMC_FLAG_ALLOCATE = 0x02, /* add entry to hash if not found */
};
/*
* The offset in sysent where the syscall is allocated.
*/
static int pmc_syscall_num = NO_SYSCALL;
struct pmc_cpu **pmc_pcpu; /* per-cpu state */
pmc_value_t *pmc_pcpu_saved; /* saved PMC values: CSW handling */
#define PMC_PCPU_SAVED(C,R) pmc_pcpu_saved[(R) + md->pmd_npmc*(C)]
struct mtx_pool *pmc_mtxpool;
static int *pmc_pmcdisp; /* PMC row dispositions */
#define PMC_ROW_DISP_IS_FREE(R) (pmc_pmcdisp[(R)] == 0)
#define PMC_ROW_DISP_IS_THREAD(R) (pmc_pmcdisp[(R)] > 0)
#define PMC_ROW_DISP_IS_STANDALONE(R) (pmc_pmcdisp[(R)] < 0)
#define PMC_MARK_ROW_FREE(R) do { \
pmc_pmcdisp[(R)] = 0; \
} while (0)
#define PMC_MARK_ROW_STANDALONE(R) do { \
KASSERT(pmc_pmcdisp[(R)] <= 0, ("[pmc,%d] row disposition error", \
__LINE__)); \
atomic_add_int(&pmc_pmcdisp[(R)], -1); \
KASSERT(pmc_pmcdisp[(R)] >= (-pmc_cpu_max_active()), \
("[pmc,%d] row disposition error", __LINE__)); \
} while (0)
#define PMC_UNMARK_ROW_STANDALONE(R) do { \
atomic_add_int(&pmc_pmcdisp[(R)], 1); \
KASSERT(pmc_pmcdisp[(R)] <= 0, ("[pmc,%d] row disposition error", \
__LINE__)); \
} while (0)
#define PMC_MARK_ROW_THREAD(R) do { \
KASSERT(pmc_pmcdisp[(R)] >= 0, ("[pmc,%d] row disposition error", \
__LINE__)); \
atomic_add_int(&pmc_pmcdisp[(R)], 1); \
} while (0)
#define PMC_UNMARK_ROW_THREAD(R) do { \
atomic_add_int(&pmc_pmcdisp[(R)], -1); \
KASSERT(pmc_pmcdisp[(R)] >= 0, ("[pmc,%d] row disposition error", \
__LINE__)); \
} while (0)
/* various event handlers */
static eventhandler_tag pmc_exit_tag, pmc_fork_tag;
/* Module statistics */
struct pmc_op_getdriverstats pmc_stats;
/* Machine/processor dependent operations */
static struct pmc_mdep *md;
/*
* Hash tables mapping owner processes and target threads to PMCs.
*/
struct mtx pmc_processhash_mtx; /* spin mutex */
static u_long pmc_processhashmask;
static LIST_HEAD(pmc_processhash, pmc_process) *pmc_processhash;
/*
* Hash table of PMC owner descriptors. This table is protected by
* the shared PMC "sx" lock.
*/
static u_long pmc_ownerhashmask;
static LIST_HEAD(pmc_ownerhash, pmc_owner) *pmc_ownerhash;
/*
* List of PMC owners with system-wide sampling PMCs.
*/
static LIST_HEAD(, pmc_owner) pmc_ss_owners;
/*
* A map of row indices to classdep structures.
*/
static struct pmc_classdep **pmc_rowindex_to_classdep;
/*
* Prototypes
*/
#ifdef DEBUG
static int pmc_debugflags_sysctl_handler(SYSCTL_HANDLER_ARGS);
static int pmc_debugflags_parse(char *newstr, char *fence);
#endif
static int load(struct module *module, int cmd, void *arg);
static int pmc_attach_process(struct proc *p, struct pmc *pm);
static struct pmc *pmc_allocate_pmc_descriptor(void);
static struct pmc_owner *pmc_allocate_owner_descriptor(struct proc *p);
static int pmc_attach_one_process(struct proc *p, struct pmc *pm);
static int pmc_can_allocate_rowindex(struct proc *p, unsigned int ri,
int cpu);
static int pmc_can_attach(struct pmc *pm, struct proc *p);
static void pmc_capture_user_callchain(int cpu, struct trapframe *tf);
static void pmc_cleanup(void);
static int pmc_detach_process(struct proc *p, struct pmc *pm);
static int pmc_detach_one_process(struct proc *p, struct pmc *pm,
int flags);
static void pmc_destroy_owner_descriptor(struct pmc_owner *po);
static struct pmc_owner *pmc_find_owner_descriptor(struct proc *p);
static int pmc_find_pmc(pmc_id_t pmcid, struct pmc **pm);
static struct pmc *pmc_find_pmc_descriptor_in_process(struct pmc_owner *po,
pmc_id_t pmc);
static struct pmc_process *pmc_find_process_descriptor(struct proc *p,
uint32_t mode);
static void pmc_force_context_switch(void);
static void pmc_link_target_process(struct pmc *pm,
struct pmc_process *pp);
static void pmc_log_all_process_mappings(struct pmc_owner *po);
static void pmc_log_kernel_mappings(struct pmc *pm);
static void pmc_log_process_mappings(struct pmc_owner *po, struct proc *p);
static void pmc_maybe_remove_owner(struct pmc_owner *po);
static void pmc_process_csw_in(struct thread *td);
static void pmc_process_csw_out(struct thread *td);
static void pmc_process_exit(void *arg, struct proc *p);
static void pmc_process_fork(void *arg, struct proc *p1,
struct proc *p2, int n);
static void pmc_process_samples(int cpu);
static void pmc_release_pmc_descriptor(struct pmc *pmc);
static void pmc_remove_owner(struct pmc_owner *po);
static void pmc_remove_process_descriptor(struct pmc_process *pp);
static void pmc_restore_cpu_binding(struct pmc_binding *pb);
static void pmc_save_cpu_binding(struct pmc_binding *pb);
static void pmc_select_cpu(int cpu);
static int pmc_start(struct pmc *pm);
static int pmc_stop(struct pmc *pm);
static int pmc_syscall_handler(struct thread *td, void *syscall_args);
static void pmc_unlink_target_process(struct pmc *pmc,
struct pmc_process *pp);
/*
* Kernel tunables and sysctl(8) interface.
*/
SYSCTL_NODE(_kern, OID_AUTO, hwpmc, CTLFLAG_RW, 0, "HWPMC parameters");
static int pmc_callchaindepth = PMC_CALLCHAIN_DEPTH;
TUNABLE_INT(PMC_SYSCTL_NAME_PREFIX "callchaindepth", &pmc_callchaindepth);
SYSCTL_INT(_kern_hwpmc, OID_AUTO, callchaindepth, CTLFLAG_TUN|CTLFLAG_RD,
&pmc_callchaindepth, 0, "depth of call chain records");
#ifdef DEBUG
struct pmc_debugflags pmc_debugflags = PMC_DEBUG_DEFAULT_FLAGS;
char pmc_debugstr[PMC_DEBUG_STRSIZE];
TUNABLE_STR(PMC_SYSCTL_NAME_PREFIX "debugflags", pmc_debugstr,
sizeof(pmc_debugstr));
SYSCTL_PROC(_kern_hwpmc, OID_AUTO, debugflags,
CTLTYPE_STRING|CTLFLAG_RW|CTLFLAG_TUN,
0, 0, pmc_debugflags_sysctl_handler, "A", "debug flags");
#endif
/*
* kern.hwpmc.hashrows -- determines the number of rows in the
* of the hash table used to look up threads
*/
static int pmc_hashsize = PMC_HASH_SIZE;
TUNABLE_INT(PMC_SYSCTL_NAME_PREFIX "hashsize", &pmc_hashsize);
SYSCTL_INT(_kern_hwpmc, OID_AUTO, hashsize, CTLFLAG_TUN|CTLFLAG_RD,
&pmc_hashsize, 0, "rows in hash tables");
/*
* kern.hwpmc.nsamples --- number of PC samples/callchain stacks per CPU
*/
static int pmc_nsamples = PMC_NSAMPLES;
TUNABLE_INT(PMC_SYSCTL_NAME_PREFIX "nsamples", &pmc_nsamples);
SYSCTL_INT(_kern_hwpmc, OID_AUTO, nsamples, CTLFLAG_TUN|CTLFLAG_RD,
&pmc_nsamples, 0, "number of PC samples per CPU");
/*
* kern.hwpmc.mtxpoolsize -- number of mutexes in the mutex pool.
*/
static int pmc_mtxpool_size = PMC_MTXPOOL_SIZE;
TUNABLE_INT(PMC_SYSCTL_NAME_PREFIX "mtxpoolsize", &pmc_mtxpool_size);
SYSCTL_INT(_kern_hwpmc, OID_AUTO, mtxpoolsize, CTLFLAG_TUN|CTLFLAG_RD,
&pmc_mtxpool_size, 0, "size of spin mutex pool");
/*
* security.bsd.unprivileged_syspmcs -- allow non-root processes to
* allocate system-wide PMCs.
*
* Allowing unprivileged processes to allocate system PMCs is convenient
* if system-wide measurements need to be taken concurrently with other
* per-process measurements. This feature is turned off by default.
*/
static int pmc_unprivileged_syspmcs = 0;
TUNABLE_INT("security.bsd.unprivileged_syspmcs", &pmc_unprivileged_syspmcs);
SYSCTL_INT(_security_bsd, OID_AUTO, unprivileged_syspmcs, CTLFLAG_RW,
&pmc_unprivileged_syspmcs, 0,
"allow unprivileged process to allocate system PMCs");
/*
* Hash function. Discard the lower 2 bits of the pointer since
* these are always zero for our uses. The hash multiplier is
* round((2^LONG_BIT) * ((sqrt(5)-1)/2)).
*/
#if LONG_BIT == 64
#define _PMC_HM 11400714819323198486u
#elif LONG_BIT == 32
#define _PMC_HM 2654435769u
#else
#error Must know the size of 'long' to compile
#endif
#define PMC_HASH_PTR(P,M) ((((unsigned long) (P) >> 2) * _PMC_HM) & (M))
/*
* Syscall structures
*/
/* The `sysent' for the new syscall */
static struct sysent pmc_sysent = {
2, /* sy_narg */
pmc_syscall_handler /* sy_call */
};
static struct syscall_module_data pmc_syscall_mod = {
load,
NULL,
&pmc_syscall_num,
&pmc_sysent,
{ 0, NULL }
};
static moduledata_t pmc_mod = {
PMC_MODULE_NAME,
syscall_module_handler,
&pmc_syscall_mod
};
DECLARE_MODULE(pmc, pmc_mod, SI_SUB_SMP, SI_ORDER_ANY);
MODULE_VERSION(pmc, PMC_VERSION);
#ifdef DEBUG
enum pmc_dbgparse_state {
PMCDS_WS, /* in whitespace */
PMCDS_MAJOR, /* seen a major keyword */
PMCDS_MINOR
};
static int
pmc_debugflags_parse(char *newstr, char *fence)
{
char c, *p, *q;
struct pmc_debugflags *tmpflags;
int error, found, *newbits, tmp;
size_t kwlen;
tmpflags = malloc(sizeof(*tmpflags), M_PMC, M_WAITOK|M_ZERO);
p = newstr;
error = 0;
for (; p < fence && (c = *p); p++) {
/* skip white space */
if (c == ' ' || c == '\t')
continue;
/* look for a keyword followed by "=" */
for (q = p; p < fence && (c = *p) && c != '='; p++)
;
if (c != '=') {
error = EINVAL;
goto done;
}
kwlen = p - q;
newbits = NULL;
/* lookup flag group name */
#define DBG_SET_FLAG_MAJ(S,F) \
if (kwlen == sizeof(S)-1 && strncmp(q, S, kwlen) == 0) \
newbits = &tmpflags->pdb_ ## F;
DBG_SET_FLAG_MAJ("cpu", CPU);
DBG_SET_FLAG_MAJ("csw", CSW);
DBG_SET_FLAG_MAJ("logging", LOG);
DBG_SET_FLAG_MAJ("module", MOD);
DBG_SET_FLAG_MAJ("md", MDP);
DBG_SET_FLAG_MAJ("owner", OWN);
DBG_SET_FLAG_MAJ("pmc", PMC);
DBG_SET_FLAG_MAJ("process", PRC);
DBG_SET_FLAG_MAJ("sampling", SAM);
if (newbits == NULL) {
error = EINVAL;
goto done;
}
p++; /* skip the '=' */
/* Now parse the individual flags */
tmp = 0;
newflag:
for (q = p; p < fence && (c = *p); p++)
if (c == ' ' || c == '\t' || c == ',')
break;
/* p == fence or c == ws or c == "," or c == 0 */
if ((kwlen = p - q) == 0) {
*newbits = tmp;
continue;
}
found = 0;
#define DBG_SET_FLAG_MIN(S,F) \
if (kwlen == sizeof(S)-1 && strncmp(q, S, kwlen) == 0) \
tmp |= found = (1 << PMC_DEBUG_MIN_ ## F)
/* a '*' denotes all possible flags in the group */
if (kwlen == 1 && *q == '*')
tmp = found = ~0;
/* look for individual flag names */
DBG_SET_FLAG_MIN("allocaterow", ALR);
DBG_SET_FLAG_MIN("allocate", ALL);
DBG_SET_FLAG_MIN("attach", ATT);
DBG_SET_FLAG_MIN("bind", BND);
DBG_SET_FLAG_MIN("config", CFG);
DBG_SET_FLAG_MIN("exec", EXC);
DBG_SET_FLAG_MIN("exit", EXT);
DBG_SET_FLAG_MIN("find", FND);
DBG_SET_FLAG_MIN("flush", FLS);
DBG_SET_FLAG_MIN("fork", FRK);
DBG_SET_FLAG_MIN("getbuf", GTB);
DBG_SET_FLAG_MIN("hook", PMH);
DBG_SET_FLAG_MIN("init", INI);
DBG_SET_FLAG_MIN("intr", INT);
DBG_SET_FLAG_MIN("linktarget", TLK);
DBG_SET_FLAG_MIN("mayberemove", OMR);
DBG_SET_FLAG_MIN("ops", OPS);
DBG_SET_FLAG_MIN("read", REA);
DBG_SET_FLAG_MIN("register", REG);
DBG_SET_FLAG_MIN("release", REL);
DBG_SET_FLAG_MIN("remove", ORM);
DBG_SET_FLAG_MIN("sample", SAM);
DBG_SET_FLAG_MIN("scheduleio", SIO);
DBG_SET_FLAG_MIN("select", SEL);
DBG_SET_FLAG_MIN("signal", SIG);
DBG_SET_FLAG_MIN("swi", SWI);
DBG_SET_FLAG_MIN("swo", SWO);
DBG_SET_FLAG_MIN("start", STA);
DBG_SET_FLAG_MIN("stop", STO);
DBG_SET_FLAG_MIN("syscall", PMS);
DBG_SET_FLAG_MIN("unlinktarget", TUL);
DBG_SET_FLAG_MIN("write", WRI);
if (found == 0) {
/* unrecognized flag name */
error = EINVAL;
goto done;
}
if (c == 0 || c == ' ' || c == '\t') { /* end of flag group */
*newbits = tmp;
continue;
}
p++;
goto newflag;
}
/* save the new flag set */
bcopy(tmpflags, &pmc_debugflags, sizeof(pmc_debugflags));
done:
free(tmpflags, M_PMC);
return error;
}
static int
pmc_debugflags_sysctl_handler(SYSCTL_HANDLER_ARGS)
{
char *fence, *newstr;
int error;
unsigned int n;
(void) arg1; (void) arg2; /* unused parameters */
n = sizeof(pmc_debugstr);
newstr = malloc(n, M_PMC, M_WAITOK|M_ZERO);
(void) strlcpy(newstr, pmc_debugstr, n);
error = sysctl_handle_string(oidp, newstr, n, req);
/* if there is a new string, parse and copy it */
if (error == 0 && req->newptr != NULL) {
fence = newstr + (n < req->newlen ? n : req->newlen + 1);
if ((error = pmc_debugflags_parse(newstr, fence)) == 0)
(void) strlcpy(pmc_debugstr, newstr,
sizeof(pmc_debugstr));
}
free(newstr, M_PMC);
return error;
}
#endif
/*
* Map a row index to a classdep structure and return the adjusted row
* index for the PMC class index.
*/
static struct pmc_classdep *
pmc_ri_to_classdep(struct pmc_mdep *md, int ri, int *adjri)
{
struct pmc_classdep *pcd;
(void) md;
KASSERT(ri >= 0 && ri < md->pmd_npmc,
("[pmc,%d] illegal row-index %d", __LINE__, ri));
pcd = pmc_rowindex_to_classdep[ri];
KASSERT(pcd != NULL,
("[amd,%d] ri %d null pcd", __LINE__, ri));
*adjri = ri - pcd->pcd_ri;
KASSERT(*adjri >= 0 && *adjri < pcd->pcd_num,
("[pmc,%d] adjusted row-index %d", __LINE__, *adjri));
return (pcd);
}
/*
* Concurrency Control
*
* The driver manages the following data structures:
*
* - target process descriptors, one per target process
* - owner process descriptors (and attached lists), one per owner process
* - lookup hash tables for owner and target processes
* - PMC descriptors (and attached lists)
* - per-cpu hardware state
* - the 'hook' variable through which the kernel calls into
* this module
* - the machine hardware state (managed by the MD layer)
*
* These data structures are accessed from:
*
* - thread context-switch code
* - interrupt handlers (possibly on multiple cpus)
* - kernel threads on multiple cpus running on behalf of user
* processes doing system calls
* - this driver's private kernel threads
*
* = Locks and Locking strategy =
*
* The driver uses four locking strategies for its operation:
*
* - The global SX lock "pmc_sx" is used to protect internal
* data structures.
*
* Calls into the module by syscall() start with this lock being
* held in exclusive mode. Depending on the requested operation,
* the lock may be downgraded to 'shared' mode to allow more
* concurrent readers into the module. Calls into the module from
* other parts of the kernel acquire the lock in shared mode.
*
* This SX lock is held in exclusive mode for any operations that
* modify the linkages between the driver's internal data structures.
*
* The 'pmc_hook' function pointer is also protected by this lock.
* It is only examined with the sx lock held in exclusive mode. The
* kernel module is allowed to be unloaded only with the sx lock held
* in exclusive mode. In normal syscall handling, after acquiring the
* pmc_sx lock we first check that 'pmc_hook' is non-null before
* proceeding. This prevents races between the thread unloading the module
* and other threads seeking to use the module.
*
* - Lookups of target process structures and owner process structures
* cannot use the global "pmc_sx" SX lock because these lookups need
* to happen during context switches and in other critical sections
* where sleeping is not allowed. We protect these lookup tables
* with their own private spin-mutexes, "pmc_processhash_mtx" and
* "pmc_ownerhash_mtx".
*
* - Interrupt handlers work in a lock free manner. At interrupt
* time, handlers look at the PMC pointer (phw->phw_pmc) configured
* when the PMC was started. If this pointer is NULL, the interrupt
* is ignored after updating driver statistics. We ensure that this
* pointer is set (using an atomic operation if necessary) before the
* PMC hardware is started. Conversely, this pointer is unset atomically
* only after the PMC hardware is stopped.
*
* We ensure that everything needed for the operation of an
* interrupt handler is available without it needing to acquire any
* locks. We also ensure that a PMC's software state is destroyed only
* after the PMC is taken off hardware (on all CPUs).
*
* - Context-switch handling with process-private PMCs needs more
* care.
*
* A given process may be the target of multiple PMCs. For example,
* PMCATTACH and PMCDETACH may be requested by a process on one CPU
* while the target process is running on another. A PMC could also
* be getting released because its owner is exiting. We tackle
* these situations in the following manner:
*
* - each target process structure 'pmc_process' has an array
* of 'struct pmc *' pointers, one for each hardware PMC.
*
* - At context switch IN time, each "target" PMC in RUNNING state
* gets started on hardware and a pointer to each PMC is copied into
* the per-cpu phw array. The 'runcount' for the PMC is
* incremented.
*
* - At context switch OUT time, all process-virtual PMCs are stopped
* on hardware. The saved value is added to the PMCs value field
* only if the PMC is in a non-deleted state (the PMCs state could
* have changed during the current time slice).
*
* Note that since in-between a switch IN on a processor and a switch
* OUT, the PMC could have been released on another CPU. Therefore
* context switch OUT always looks at the hardware state to turn
* OFF PMCs and will update a PMC's saved value only if reachable
* from the target process record.
*
* - OP PMCRELEASE could be called on a PMC at any time (the PMC could
* be attached to many processes at the time of the call and could
* be active on multiple CPUs).
*
* We prevent further scheduling of the PMC by marking it as in
* state 'DELETED'. If the runcount of the PMC is non-zero then
* this PMC is currently running on a CPU somewhere. The thread
* doing the PMCRELEASE operation waits by repeatedly doing a
* pause() till the runcount comes to zero.
*
* The contents of a PMC descriptor (struct pmc) are protected using
* a spin-mutex. In order to save space, we use a mutex pool.
*
* In terms of lock types used by witness(4), we use:
* - Type "pmc-sx", used by the global SX lock.
* - Type "pmc-sleep", for sleep mutexes used by logger threads.
* - Type "pmc-per-proc", for protecting PMC owner descriptors.
* - Type "pmc-leaf", used for all other spin mutexes.
*/
/*
* save the cpu binding of the current kthread
*/
static void
pmc_save_cpu_binding(struct pmc_binding *pb)
{
PMCDBG(CPU,BND,2, "%s", "save-cpu");
thread_lock(curthread);
pb->pb_bound = sched_is_bound(curthread);
pb->pb_cpu = curthread->td_oncpu;
thread_unlock(curthread);
PMCDBG(CPU,BND,2, "save-cpu cpu=%d", pb->pb_cpu);
}
/*
* restore the cpu binding of the current thread
*/
static void
pmc_restore_cpu_binding(struct pmc_binding *pb)
{
PMCDBG(CPU,BND,2, "restore-cpu curcpu=%d restore=%d",
curthread->td_oncpu, pb->pb_cpu);
thread_lock(curthread);
if (pb->pb_bound)
sched_bind(curthread, pb->pb_cpu);
else
sched_unbind(curthread);
thread_unlock(curthread);
PMCDBG(CPU,BND,2, "%s", "restore-cpu done");
}
/*
* move execution over the specified cpu and bind it there.
*/
static void
pmc_select_cpu(int cpu)
{
KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
("[pmc,%d] bad cpu number %d", __LINE__, cpu));
/* Never move to an inactive CPU. */
KASSERT(pmc_cpu_is_active(cpu), ("[pmc,%d] selecting inactive "
"CPU %d", __LINE__, cpu));
PMCDBG(CPU,SEL,2, "select-cpu cpu=%d", cpu);
thread_lock(curthread);
sched_bind(curthread, cpu);
thread_unlock(curthread);
KASSERT(curthread->td_oncpu == cpu,
("[pmc,%d] CPU not bound [cpu=%d, curr=%d]", __LINE__,
cpu, curthread->td_oncpu));
PMCDBG(CPU,SEL,2, "select-cpu cpu=%d ok", cpu);
}
/*
* Force a context switch.
*
* We do this by pause'ing for 1 tick -- invoking mi_switch() is not
* guaranteed to force a context switch.
*/
static void
pmc_force_context_switch(void)
{
pause("pmcctx", 1);
}
/*
* Get the file name for an executable. This is a simple wrapper
* around vn_fullpath(9).
*/
static void
pmc_getfilename(struct vnode *v, char **fullpath, char **freepath)
{
*fullpath = "unknown";
*freepath = NULL;
vn_fullpath(curthread, v, fullpath, freepath);
}
/*
* remove an process owning PMCs
*/
void
pmc_remove_owner(struct pmc_owner *po)
{
struct pmc *pm, *tmp;
sx_assert(&pmc_sx, SX_XLOCKED);
PMCDBG(OWN,ORM,1, "remove-owner po=%p", po);
/* Remove descriptor from the owner hash table */
LIST_REMOVE(po, po_next);
/* release all owned PMC descriptors */
LIST_FOREACH_SAFE(pm, &po->po_pmcs, pm_next, tmp) {
PMCDBG(OWN,ORM,2, "pmc=%p", pm);
KASSERT(pm->pm_owner == po,
("[pmc,%d] owner %p != po %p", __LINE__, pm->pm_owner, po));
pmc_release_pmc_descriptor(pm); /* will unlink from the list */
}
KASSERT(po->po_sscount == 0,
("[pmc,%d] SS count not zero", __LINE__));
KASSERT(LIST_EMPTY(&po->po_pmcs),
("[pmc,%d] PMC list not empty", __LINE__));
/* de-configure the log file if present */
if (po->po_flags & PMC_PO_OWNS_LOGFILE)
pmclog_deconfigure_log(po);
}
/*
* remove an owner process record if all conditions are met.
*/
static void
pmc_maybe_remove_owner(struct pmc_owner *po)
{
PMCDBG(OWN,OMR,1, "maybe-remove-owner po=%p", po);
/*
* Remove owner record if
* - this process does not own any PMCs
* - this process has not allocated a system-wide sampling buffer
*/
if (LIST_EMPTY(&po->po_pmcs) &&
((po->po_flags & PMC_PO_OWNS_LOGFILE) == 0)) {
pmc_remove_owner(po);
pmc_destroy_owner_descriptor(po);
}
}
/*
* Add an association between a target process and a PMC.
*/
static void
pmc_link_target_process(struct pmc *pm, struct pmc_process *pp)
{
int ri;
struct pmc_target *pt;
sx_assert(&pmc_sx, SX_XLOCKED);
KASSERT(pm != NULL && pp != NULL,
("[pmc,%d] Null pm %p or pp %p", __LINE__, pm, pp));
KASSERT(PMC_IS_VIRTUAL_MODE(PMC_TO_MODE(pm)),
("[pmc,%d] Attaching a non-process-virtual pmc=%p to pid=%d",
__LINE__, pm, pp->pp_proc->p_pid));
KASSERT(pp->pp_refcnt >= 0 && pp->pp_refcnt < ((int) md->pmd_npmc - 1),
("[pmc,%d] Illegal reference count %d for process record %p",
__LINE__, pp->pp_refcnt, (void *) pp));
ri = PMC_TO_ROWINDEX(pm);
PMCDBG(PRC,TLK,1, "link-target pmc=%p ri=%d pmc-process=%p",
pm, ri, pp);
#ifdef DEBUG
LIST_FOREACH(pt, &pm->pm_targets, pt_next)
if (pt->pt_process == pp)
KASSERT(0, ("[pmc,%d] pp %p already in pmc %p targets",
__LINE__, pp, pm));
#endif
pt = malloc(sizeof(struct pmc_target), M_PMC, M_WAITOK|M_ZERO);
pt->pt_process = pp;
LIST_INSERT_HEAD(&pm->pm_targets, pt, pt_next);
atomic_store_rel_ptr((uintptr_t *)&pp->pp_pmcs[ri].pp_pmc,
(uintptr_t)pm);
if (pm->pm_owner->po_owner == pp->pp_proc)
pm->pm_flags |= PMC_F_ATTACHED_TO_OWNER;
/*
* Initialize the per-process values at this row index.
*/
pp->pp_pmcs[ri].pp_pmcval = PMC_TO_MODE(pm) == PMC_MODE_TS ?
pm->pm_sc.pm_reloadcount : 0;
pp->pp_refcnt++;
}
/*
* Removes the association between a target process and a PMC.
*/
static void
pmc_unlink_target_process(struct pmc *pm, struct pmc_process *pp)
{
int ri;
struct proc *p;
struct pmc_target *ptgt;
sx_assert(&pmc_sx, SX_XLOCKED);
KASSERT(pm != NULL && pp != NULL,
("[pmc,%d] Null pm %p or pp %p", __LINE__, pm, pp));
KASSERT(pp->pp_refcnt >= 1 && pp->pp_refcnt < (int) md->pmd_npmc,
("[pmc,%d] Illegal ref count %d on process record %p",
__LINE__, pp->pp_refcnt, (void *) pp));
ri = PMC_TO_ROWINDEX(pm);
PMCDBG(PRC,TUL,1, "unlink-target pmc=%p ri=%d pmc-process=%p",
pm, ri, pp);
KASSERT(pp->pp_pmcs[ri].pp_pmc == pm,
("[pmc,%d] PMC ri %d mismatch pmc %p pp->[ri] %p", __LINE__,
ri, pm, pp->pp_pmcs[ri].pp_pmc));
pp->pp_pmcs[ri].pp_pmc = NULL;
pp->pp_pmcs[ri].pp_pmcval = (pmc_value_t) 0;
/* Remove owner-specific flags */
if (pm->pm_owner->po_owner == pp->pp_proc) {
pp->pp_flags &= ~PMC_PP_ENABLE_MSR_ACCESS;
pm->pm_flags &= ~PMC_F_ATTACHED_TO_OWNER;
}
pp->pp_refcnt--;
/* Remove the target process from the PMC structure */
LIST_FOREACH(ptgt, &pm->pm_targets, pt_next)
if (ptgt->pt_process == pp)
break;
KASSERT(ptgt != NULL, ("[pmc,%d] process %p (pp: %p) not found "
"in pmc %p", __LINE__, pp->pp_proc, pp, pm));
LIST_REMOVE(ptgt, pt_next);
free(ptgt, M_PMC);
/* if the PMC now lacks targets, send the owner a SIGIO */
if (LIST_EMPTY(&pm->pm_targets)) {
p = pm->pm_owner->po_owner;
PROC_LOCK(p);
psignal(p, SIGIO);
PROC_UNLOCK(p);
PMCDBG(PRC,SIG,2, "signalling proc=%p signal=%d", p,
SIGIO);
}
}
/*
* Check if PMC 'pm' may be attached to target process 't'.
*/
static int
pmc_can_attach(struct pmc *pm, struct proc *t)
{
struct proc *o; /* pmc owner */
struct ucred *oc, *tc; /* owner, target credentials */
int decline_attach, i;
/*
* A PMC's owner can always attach that PMC to itself.
*/
if ((o = pm->pm_owner->po_owner) == t)
return 0;
PROC_LOCK(o);
oc = o->p_ucred;
crhold(oc);
PROC_UNLOCK(o);
PROC_LOCK(t);
tc = t->p_ucred;
crhold(tc);
PROC_UNLOCK(t);
/*
* The effective uid of the PMC owner should match at least one
* of the {effective,real,saved} uids of the target process.
*/
decline_attach = oc->cr_uid != tc->cr_uid &&
oc->cr_uid != tc->cr_svuid &&
oc->cr_uid != tc->cr_ruid;
/*
* Every one of the target's group ids, must be in the owner's
* group list.
*/
for (i = 0; !decline_attach && i < tc->cr_ngroups; i++)
decline_attach = !groupmember(tc->cr_groups[i], oc);
/* check the read and saved gids too */
if (decline_attach == 0)
decline_attach = !groupmember(tc->cr_rgid, oc) ||
!groupmember(tc->cr_svgid, oc);
crfree(tc);
crfree(oc);
return !decline_attach;
}
/*
* Attach a process to a PMC.
*/
static int
pmc_attach_one_process(struct proc *p, struct pmc *pm)
{
int ri;
char *fullpath, *freepath;
struct pmc_process *pp;
sx_assert(&pmc_sx, SX_XLOCKED);
PMCDBG(PRC,ATT,2, "attach-one pm=%p ri=%d proc=%p (%d, %s)", pm,
PMC_TO_ROWINDEX(pm), p, p->p_pid, p->p_comm);
/*
* Locate the process descriptor corresponding to process 'p',
* allocating space as needed.
*
* Verify that rowindex 'pm_rowindex' is free in the process
* descriptor.
*
* If not, allocate space for a descriptor and link the
* process descriptor and PMC.
*/
ri = PMC_TO_ROWINDEX(pm);
if ((pp = pmc_find_process_descriptor(p, PMC_FLAG_ALLOCATE)) == NULL)
return ENOMEM;
if (pp->pp_pmcs[ri].pp_pmc == pm) /* already present at slot [ri] */
return EEXIST;
if (pp->pp_pmcs[ri].pp_pmc != NULL)
return EBUSY;
pmc_link_target_process(pm, pp);
if (PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)) &&
(pm->pm_flags & PMC_F_ATTACHED_TO_OWNER) == 0)
pm->pm_flags |= PMC_F_NEEDS_LOGFILE;
pm->pm_flags |= PMC_F_ATTACH_DONE; /* mark as attached */
/* issue an attach event to a configured log file */
if (pm->pm_owner->po_flags & PMC_PO_OWNS_LOGFILE) {
pmc_getfilename(p->p_textvp, &fullpath, &freepath);
if (p->p_flag & P_KTHREAD) {
fullpath = kernelname;
freepath = NULL;
} else
pmclog_process_pmcattach(pm, p->p_pid, fullpath);
if (freepath)
free(freepath, M_TEMP);
if (PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)))
pmc_log_process_mappings(pm->pm_owner, p);
}
/* mark process as using HWPMCs */
PROC_LOCK(p);
p->p_flag |= P_HWPMC;
PROC_UNLOCK(p);
return 0;
}
/*
* Attach a process and optionally its children
*/
static int
pmc_attach_process(struct proc *p, struct pmc *pm)
{
int error;
struct proc *top;
sx_assert(&pmc_sx, SX_XLOCKED);
PMCDBG(PRC,ATT,1, "attach pm=%p ri=%d proc=%p (%d, %s)", pm,
PMC_TO_ROWINDEX(pm), p, p->p_pid, p->p_comm);
/*
* If this PMC successfully allowed a GETMSR operation
* in the past, disallow further ATTACHes.
*/
if ((pm->pm_flags & PMC_PP_ENABLE_MSR_ACCESS) != 0)
return EPERM;
if ((pm->pm_flags & PMC_F_DESCENDANTS) == 0)
return pmc_attach_one_process(p, pm);
/*
* Traverse all child processes, attaching them to
* this PMC.
*/
sx_slock(&proctree_lock);
top = p;
for (;;) {
if ((error = pmc_attach_one_process(p, pm)) != 0)
break;
if (!LIST_EMPTY(&p->p_children))
p = LIST_FIRST(&p->p_children);
else for (;;) {
if (p == top)
goto done;
if (LIST_NEXT(p, p_sibling)) {
p = LIST_NEXT(p, p_sibling);
break;
}
p = p->p_pptr;
}
}
if (error)
(void) pmc_detach_process(top, pm);
done:
sx_sunlock(&proctree_lock);
return error;
}
/*
* Detach a process from a PMC. If there are no other PMCs tracking
* this process, remove the process structure from its hash table. If
* 'flags' contains PMC_FLAG_REMOVE, then free the process structure.
*/
static int
pmc_detach_one_process(struct proc *p, struct pmc *pm, int flags)
{
int ri;
struct pmc_process *pp;
sx_assert(&pmc_sx, SX_XLOCKED);
KASSERT(pm != NULL,
("[pmc,%d] null pm pointer", __LINE__));
ri = PMC_TO_ROWINDEX(pm);
PMCDBG(PRC,ATT,2, "detach-one pm=%p ri=%d proc=%p (%d, %s) flags=0x%x",
pm, ri, p, p->p_pid, p->p_comm, flags);
if ((pp = pmc_find_process_descriptor(p, 0)) == NULL)
return ESRCH;
if (pp->pp_pmcs[ri].pp_pmc != pm)
return EINVAL;
pmc_unlink_target_process(pm, pp);
/* Issue a detach entry if a log file is configured */
if (pm->pm_owner->po_flags & PMC_PO_OWNS_LOGFILE)
pmclog_process_pmcdetach(pm, p->p_pid);
/*
* If there are no PMCs targetting this process, we remove its
* descriptor from the target hash table and unset the P_HWPMC
* flag in the struct proc.
*/
KASSERT(pp->pp_refcnt >= 0 && pp->pp_refcnt < (int) md->pmd_npmc,
("[pmc,%d] Illegal refcnt %d for process struct %p",
__LINE__, pp->pp_refcnt, pp));
if (pp->pp_refcnt != 0) /* still a target of some PMC */
return 0;
pmc_remove_process_descriptor(pp);
if (flags & PMC_FLAG_REMOVE)
free(pp, M_PMC);
PROC_LOCK(p);
p->p_flag &= ~P_HWPMC;
PROC_UNLOCK(p);
return 0;
}
/*
* Detach a process and optionally its descendants from a PMC.
*/
static int
pmc_detach_process(struct proc *p, struct pmc *pm)
{
struct proc *top;
sx_assert(&pmc_sx, SX_XLOCKED);
PMCDBG(PRC,ATT,1, "detach pm=%p ri=%d proc=%p (%d, %s)", pm,
PMC_TO_ROWINDEX(pm), p, p->p_pid, p->p_comm);
if ((pm->pm_flags & PMC_F_DESCENDANTS) == 0)
return pmc_detach_one_process(p, pm, PMC_FLAG_REMOVE);
/*
* Traverse all children, detaching them from this PMC. We
* ignore errors since we could be detaching a PMC from a
* partially attached proc tree.
*/
sx_slock(&proctree_lock);
top = p;
for (;;) {
(void) pmc_detach_one_process(p, pm, PMC_FLAG_REMOVE);
if (!LIST_EMPTY(&p->p_children))
p = LIST_FIRST(&p->p_children);
else for (;;) {
if (p == top)
goto done;
if (LIST_NEXT(p, p_sibling)) {
p = LIST_NEXT(p, p_sibling);
break;
}
p = p->p_pptr;
}
}
done:
sx_sunlock(&proctree_lock);
if (LIST_EMPTY(&pm->pm_targets))
pm->pm_flags &= ~PMC_F_ATTACH_DONE;
return 0;
}
/*
* Thread context switch IN
*/
static void
pmc_process_csw_in(struct thread *td)
{
int cpu;
unsigned int adjri, ri;
struct pmc *pm;
struct proc *p;
struct pmc_cpu *pc;
struct pmc_hw *phw;
pmc_value_t newvalue;
struct pmc_process *pp;
struct pmc_classdep *pcd;
p = td->td_proc;
if ((pp = pmc_find_process_descriptor(p, PMC_FLAG_NONE)) == NULL)
return;
KASSERT(pp->pp_proc == td->td_proc,
("[pmc,%d] not my thread state", __LINE__));
critical_enter(); /* no preemption from this point */
cpu = PCPU_GET(cpuid); /* td->td_oncpu is invalid */
PMCDBG(CSW,SWI,1, "cpu=%d proc=%p (%d, %s) pp=%p", cpu, p,
p->p_pid, p->p_comm, pp);
KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
("[pmc,%d] wierd CPU id %d", __LINE__, cpu));
pc = pmc_pcpu[cpu];
for (ri = 0; ri < md->pmd_npmc; ri++) {
if ((pm = pp->pp_pmcs[ri].pp_pmc) == NULL)
continue;
KASSERT(PMC_IS_VIRTUAL_MODE(PMC_TO_MODE(pm)),
("[pmc,%d] Target PMC in non-virtual mode (%d)",
__LINE__, PMC_TO_MODE(pm)));
KASSERT(PMC_TO_ROWINDEX(pm) == ri,
("[pmc,%d] Row index mismatch pmc %d != ri %d",
__LINE__, PMC_TO_ROWINDEX(pm), ri));
/*
* Only PMCs that are marked as 'RUNNING' need
* be placed on hardware.
*/
if (pm->pm_state != PMC_STATE_RUNNING)
continue;
/* increment PMC runcount */
atomic_add_rel_32(&pm->pm_runcount, 1);
/* configure the HWPMC we are going to use. */
pcd = pmc_ri_to_classdep(md, ri, &adjri);
pcd->pcd_config_pmc(cpu, adjri, pm);
phw = pc->pc_hwpmcs[ri];
KASSERT(phw != NULL,
("[pmc,%d] null hw pointer", __LINE__));
KASSERT(phw->phw_pmc == pm,
("[pmc,%d] hw->pmc %p != pmc %p", __LINE__,
phw->phw_pmc, pm));
/*
* Write out saved value and start the PMC.
*
* Sampling PMCs use a per-process value, while
* counting mode PMCs use a per-pmc value that is
* inherited across descendants.
*/
if (PMC_TO_MODE(pm) == PMC_MODE_TS) {
mtx_pool_lock_spin(pmc_mtxpool, pm);
newvalue = PMC_PCPU_SAVED(cpu,ri) =
pp->pp_pmcs[ri].pp_pmcval;
mtx_pool_unlock_spin(pmc_mtxpool, pm);
} else {
KASSERT(PMC_TO_MODE(pm) == PMC_MODE_TC,
("[pmc,%d] illegal mode=%d", __LINE__,
PMC_TO_MODE(pm)));
mtx_pool_lock_spin(pmc_mtxpool, pm);
newvalue = PMC_PCPU_SAVED(cpu, ri) =
pm->pm_gv.pm_savedvalue;
mtx_pool_unlock_spin(pmc_mtxpool, pm);
}
PMCDBG(CSW,SWI,1,"cpu=%d ri=%d new=%jd", cpu, ri, newvalue);
pcd->pcd_write_pmc(cpu, adjri, newvalue);
pcd->pcd_start_pmc(cpu, adjri);
}
/*
* perform any other architecture/cpu dependent thread
* switch-in actions.
*/
(void) (*md->pmd_switch_in)(pc, pp);
critical_exit();
}
/*
* Thread context switch OUT.
*/
static void
pmc_process_csw_out(struct thread *td)
{
int cpu;
int64_t tmp;
struct pmc *pm;
struct proc *p;
enum pmc_mode mode;
struct pmc_cpu *pc;
pmc_value_t newvalue;
unsigned int adjri, ri;
struct pmc_process *pp;
struct pmc_classdep *pcd;
/*
* Locate our process descriptor; this may be NULL if
* this process is exiting and we have already removed
* the process from the target process table.
*
* Note that due to kernel preemption, multiple
* context switches may happen while the process is
* exiting.
*
* Note also that if the target process cannot be
* found we still need to deconfigure any PMCs that
* are currently running on hardware.
*/
p = td->td_proc;
pp = pmc_find_process_descriptor(p, PMC_FLAG_NONE);
/*
* save PMCs
*/
critical_enter();
cpu = PCPU_GET(cpuid); /* td->td_oncpu is invalid */
PMCDBG(CSW,SWO,1, "cpu=%d proc=%p (%d, %s) pp=%p", cpu, p,
p->p_pid, p->p_comm, pp);
KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
("[pmc,%d wierd CPU id %d", __LINE__, cpu));
pc = pmc_pcpu[cpu];
/*
* When a PMC gets unlinked from a target PMC, it will
* be removed from the target's pp_pmc[] array.
*
* However, on a MP system, the target could have been
* executing on another CPU at the time of the unlink.
* So, at context switch OUT time, we need to look at
* the hardware to determine if a PMC is scheduled on
* it.
*/
for (ri = 0; ri < md->pmd_npmc; ri++) {
pcd = pmc_ri_to_classdep(md, ri, &adjri);
pm = NULL;
(void) (*pcd->pcd_get_config)(cpu, adjri, &pm);
if (pm == NULL) /* nothing at this row index */
continue;
mode = PMC_TO_MODE(pm);
if (!PMC_IS_VIRTUAL_MODE(mode))
continue; /* not a process virtual PMC */
KASSERT(PMC_TO_ROWINDEX(pm) == ri,
("[pmc,%d] ri mismatch pmc(%d) ri(%d)",
__LINE__, PMC_TO_ROWINDEX(pm), ri));
/* Stop hardware if not already stopped */
if (pm->pm_stalled == 0)
pcd->pcd_stop_pmc(cpu, adjri);
/* reduce this PMC's runcount */
atomic_subtract_rel_32(&pm->pm_runcount, 1);
/*
* If this PMC is associated with this process,
* save the reading.
*/
if (pp != NULL && pp->pp_pmcs[ri].pp_pmc != NULL) {
KASSERT(pm == pp->pp_pmcs[ri].pp_pmc,
("[pmc,%d] pm %p != pp_pmcs[%d] %p", __LINE__,
pm, ri, pp->pp_pmcs[ri].pp_pmc));
KASSERT(pp->pp_refcnt > 0,
("[pmc,%d] pp refcnt = %d", __LINE__,
pp->pp_refcnt));
pcd->pcd_read_pmc(cpu, adjri, &newvalue);
tmp = newvalue - PMC_PCPU_SAVED(cpu,ri);
PMCDBG(CSW,SWI,1,"cpu=%d ri=%d tmp=%jd", cpu, ri,
tmp);
if (mode == PMC_MODE_TS) {
/*
* For sampling process-virtual PMCs,
* we expect the count to be
* decreasing as the 'value'
* programmed into the PMC is the
* number of events to be seen till
* the next sampling interrupt.
*/
if (tmp < 0)
tmp += pm->pm_sc.pm_reloadcount;
mtx_pool_lock_spin(pmc_mtxpool, pm);
pp->pp_pmcs[ri].pp_pmcval -= tmp;
if ((int64_t) pp->pp_pmcs[ri].pp_pmcval < 0)
pp->pp_pmcs[ri].pp_pmcval +=
pm->pm_sc.pm_reloadcount;
mtx_pool_unlock_spin(pmc_mtxpool, pm);
} else {
/*
* For counting process-virtual PMCs,
* we expect the count to be
* increasing monotonically, modulo a 64
* bit wraparound.
*/
KASSERT((int64_t) tmp >= 0,
("[pmc,%d] negative increment cpu=%d "
"ri=%d newvalue=%jx saved=%jx "
"incr=%jx", __LINE__, cpu, ri,
newvalue, PMC_PCPU_SAVED(cpu,ri), tmp));
mtx_pool_lock_spin(pmc_mtxpool, pm);
pm->pm_gv.pm_savedvalue += tmp;
pp->pp_pmcs[ri].pp_pmcval += tmp;
mtx_pool_unlock_spin(pmc_mtxpool, pm);
if (pm->pm_flags & PMC_F_LOG_PROCCSW)
pmclog_process_proccsw(pm, pp, tmp);
}
}
/* mark hardware as free */
pcd->pcd_config_pmc(cpu, adjri, NULL);
}
/*
* perform any other architecture/cpu dependent thread
* switch out functions.
*/
(void) (*md->pmd_switch_out)(pc, pp);
critical_exit();
}
/*
* Log a KLD operation.
*/
static void
pmc_process_kld_load(struct pmckern_map_in *pkm)
{
struct pmc_owner *po;
sx_assert(&pmc_sx, SX_LOCKED);
/*
* Notify owners of system sampling PMCs about KLD operations.
*/
LIST_FOREACH(po, &pmc_ss_owners, po_ssnext)
if (po->po_flags & PMC_PO_OWNS_LOGFILE)
pmclog_process_map_in(po, (pid_t) -1, pkm->pm_address,
(char *) pkm->pm_file);
/*
* TODO: Notify owners of (all) process-sampling PMCs too.
*/
return;
}
static void
pmc_process_kld_unload(struct pmckern_map_out *pkm)
{
struct pmc_owner *po;
sx_assert(&pmc_sx, SX_LOCKED);
LIST_FOREACH(po, &pmc_ss_owners, po_ssnext)
if (po->po_flags & PMC_PO_OWNS_LOGFILE)
pmclog_process_map_out(po, (pid_t) -1,
pkm->pm_address, pkm->pm_address + pkm->pm_size);
/*
* TODO: Notify owners of process-sampling PMCs.
*/
}
/*
* A mapping change for a process.
*/
static void
pmc_process_mmap(struct thread *td, struct pmckern_map_in *pkm)
{
int ri;
pid_t pid;
char *fullpath, *freepath;
const struct pmc *pm;
struct pmc_owner *po;
const struct pmc_process *pp;
freepath = fullpath = NULL;
pmc_getfilename((struct vnode *) pkm->pm_file, &fullpath, &freepath);
pid = td->td_proc->p_pid;
/* Inform owners of all system-wide sampling PMCs. */
LIST_FOREACH(po, &pmc_ss_owners, po_ssnext)
if (po->po_flags & PMC_PO_OWNS_LOGFILE)
pmclog_process_map_in(po, pid, pkm->pm_address, fullpath);
if ((pp = pmc_find_process_descriptor(td->td_proc, 0)) == NULL)
goto done;
/*
* Inform sampling PMC owners tracking this process.
*/
for (ri = 0; ri < md->pmd_npmc; ri++)
if ((pm = pp->pp_pmcs[ri].pp_pmc) != NULL &&
PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)))
pmclog_process_map_in(pm->pm_owner,
pid, pkm->pm_address, fullpath);
done:
if (freepath)
free(freepath, M_TEMP);
}
/*
* Log an munmap request.
*/
static void
pmc_process_munmap(struct thread *td, struct pmckern_map_out *pkm)
{
int ri;
pid_t pid;
struct pmc_owner *po;
const struct pmc *pm;
const struct pmc_process *pp;
pid = td->td_proc->p_pid;
LIST_FOREACH(po, &pmc_ss_owners, po_ssnext)
if (po->po_flags & PMC_PO_OWNS_LOGFILE)
pmclog_process_map_out(po, pid, pkm->pm_address,
pkm->pm_address + pkm->pm_size);
if ((pp = pmc_find_process_descriptor(td->td_proc, 0)) == NULL)
return;
for (ri = 0; ri < md->pmd_npmc; ri++)
if ((pm = pp->pp_pmcs[ri].pp_pmc) != NULL &&
PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)))
pmclog_process_map_out(pm->pm_owner, pid,
pkm->pm_address, pkm->pm_address + pkm->pm_size);
}
/*
* Log mapping information about the kernel.
*/
static void
pmc_log_kernel_mappings(struct pmc *pm)
{
struct pmc_owner *po;
struct pmckern_map_in *km, *kmbase;
sx_assert(&pmc_sx, SX_LOCKED);
KASSERT(PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)),
("[pmc,%d] non-sampling PMC (%p) desires mapping information",
__LINE__, (void *) pm));
po = pm->pm_owner;
if (po->po_flags & PMC_PO_INITIAL_MAPPINGS_DONE)
return;
/*
* Log the current set of kernel modules.
*/
kmbase = linker_hwpmc_list_objects();
for (km = kmbase; km->pm_file != NULL; km++) {
PMCDBG(LOG,REG,1,"%s %p", (char *) km->pm_file,
(void *) km->pm_address);
pmclog_process_map_in(po, (pid_t) -1, km->pm_address,
km->pm_file);
}
free(kmbase, M_LINKER);
po->po_flags |= PMC_PO_INITIAL_MAPPINGS_DONE;
}
/*
* Log the mappings for a single process.
*/
static void
pmc_log_process_mappings(struct pmc_owner *po, struct proc *p)
{
}
/*
* Log mappings for all processes in the system.
*/
static void
pmc_log_all_process_mappings(struct pmc_owner *po)
{
struct proc *p, *top;
sx_assert(&pmc_sx, SX_XLOCKED);
if ((p = pfind(1)) == NULL)
panic("[pmc,%d] Cannot find init", __LINE__);
PROC_UNLOCK(p);
sx_slock(&proctree_lock);
top = p;
for (;;) {
pmc_log_process_mappings(po, p);
if (!LIST_EMPTY(&p->p_children))
p = LIST_FIRST(&p->p_children);
else for (;;) {
if (p == top)
goto done;
if (LIST_NEXT(p, p_sibling)) {
p = LIST_NEXT(p, p_sibling);
break;
}
p = p->p_pptr;
}
}
done:
sx_sunlock(&proctree_lock);
}
/*
* The 'hook' invoked from the kernel proper
*/
#ifdef DEBUG
const char *pmc_hooknames[] = {
/* these strings correspond to PMC_FN_* in <sys/pmckern.h> */
"",
"EXEC",
"CSW-IN",
"CSW-OUT",
"SAMPLE",
"KLDLOAD",
"KLDUNLOAD",
"MMAP",
"MUNMAP",
"CALLCHAIN"
};
#endif
static int
pmc_hook_handler(struct thread *td, int function, void *arg)
{
PMCDBG(MOD,PMH,1, "hook td=%p func=%d \"%s\" arg=%p", td, function,
pmc_hooknames[function], arg);
switch (function)
{
/*
* Process exec()
*/
case PMC_FN_PROCESS_EXEC:
{
char *fullpath, *freepath;
unsigned int ri;
int is_using_hwpmcs;
struct pmc *pm;
struct proc *p;
struct pmc_owner *po;
struct pmc_process *pp;
struct pmckern_procexec *pk;
sx_assert(&pmc_sx, SX_XLOCKED);
p = td->td_proc;
pmc_getfilename(p->p_textvp, &fullpath, &freepath);
pk = (struct pmckern_procexec *) arg;
/* Inform owners of SS mode PMCs of the exec event. */
LIST_FOREACH(po, &pmc_ss_owners, po_ssnext)
if (po->po_flags & PMC_PO_OWNS_LOGFILE)
pmclog_process_procexec(po, PMC_ID_INVALID,
p->p_pid, pk->pm_entryaddr, fullpath);
PROC_LOCK(p);
is_using_hwpmcs = p->p_flag & P_HWPMC;
PROC_UNLOCK(p);
if (!is_using_hwpmcs) {
if (freepath)
free(freepath, M_TEMP);
break;
}
/*
* PMCs are not inherited across an exec(): remove any
* PMCs that this process is the owner of.
*/
if ((po = pmc_find_owner_descriptor(p)) != NULL) {
pmc_remove_owner(po);
pmc_destroy_owner_descriptor(po);
}
/*
* If the process being exec'ed is not the target of any
* PMC, we are done.
*/
if ((pp = pmc_find_process_descriptor(p, 0)) == NULL) {
if (freepath)
free(freepath, M_TEMP);
break;
}
/*
* Log the exec event to all monitoring owners. Skip
* owners who have already recieved the event because
* they had system sampling PMCs active.
*/
for (ri = 0; ri < md->pmd_npmc; ri++)
if ((pm = pp->pp_pmcs[ri].pp_pmc) != NULL) {
po = pm->pm_owner;
if (po->po_sscount == 0 &&
po->po_flags & PMC_PO_OWNS_LOGFILE)
pmclog_process_procexec(po, pm->pm_id,
p->p_pid, pk->pm_entryaddr,
fullpath);
}
if (freepath)
free(freepath, M_TEMP);
PMCDBG(PRC,EXC,1, "exec proc=%p (%d, %s) cred-changed=%d",
p, p->p_pid, p->p_comm, pk->pm_credentialschanged);
if (pk->pm_credentialschanged == 0) /* no change */
break;
/*
* If the newly exec()'ed process has a different credential
* than before, allow it to be the target of a PMC only if
* the PMC's owner has sufficient priviledge.
*/
for (ri = 0; ri < md->pmd_npmc; ri++)
if ((pm = pp->pp_pmcs[ri].pp_pmc) != NULL)
if (pmc_can_attach(pm, td->td_proc) != 0)
pmc_detach_one_process(td->td_proc,
pm, PMC_FLAG_NONE);
KASSERT(pp->pp_refcnt >= 0 && pp->pp_refcnt < (int) md->pmd_npmc,
("[pmc,%d] Illegal ref count %d on pp %p", __LINE__,
pp->pp_refcnt, pp));
/*
* If this process is no longer the target of any
* PMCs, we can remove the process entry and free
* up space.
*/
if (pp->pp_refcnt == 0) {
pmc_remove_process_descriptor(pp);
free(pp, M_PMC);
break;
}
}
break;
case PMC_FN_CSW_IN:
pmc_process_csw_in(td);
break;
case PMC_FN_CSW_OUT:
pmc_process_csw_out(td);
break;
/*
* Process accumulated PC samples.
*
* This function is expected to be called by hardclock() for
* each CPU that has accumulated PC samples.
*
* This function is to be executed on the CPU whose samples
* are being processed.
*/
case PMC_FN_DO_SAMPLES:
/*
* Clear the cpu specific bit in the CPU mask before
* do the rest of the processing. If the NMI handler
* gets invoked after the "atomic_clear_int()" call
* below but before "pmc_process_samples()" gets
* around to processing the interrupt, then we will
* come back here at the next hardclock() tick (and
* may find nothing to do if "pmc_process_samples()"
* had already processed the interrupt). We don't
* lose the interrupt sample.
*/
atomic_clear_int(&pmc_cpumask, (1 << PCPU_GET(cpuid)));
pmc_process_samples(PCPU_GET(cpuid));
break;
case PMC_FN_KLD_LOAD:
sx_assert(&pmc_sx, SX_LOCKED);
pmc_process_kld_load((struct pmckern_map_in *) arg);
break;
case PMC_FN_KLD_UNLOAD:
sx_assert(&pmc_sx, SX_LOCKED);
pmc_process_kld_unload((struct pmckern_map_out *) arg);
break;
case PMC_FN_MMAP:
sx_assert(&pmc_sx, SX_LOCKED);
pmc_process_mmap(td, (struct pmckern_map_in *) arg);
break;
case PMC_FN_MUNMAP:
sx_assert(&pmc_sx, SX_LOCKED);
pmc_process_munmap(td, (struct pmckern_map_out *) arg);
break;
case PMC_FN_USER_CALLCHAIN:
/*
* Record a call chain.
*/
KASSERT(td == curthread, ("[pmc,%d] td != curthread",
__LINE__));
pmc_capture_user_callchain(PCPU_GET(cpuid),
(struct trapframe *) arg);
td->td_pflags &= ~TDP_CALLCHAIN;
break;
default:
#ifdef DEBUG
KASSERT(0, ("[pmc,%d] unknown hook %d\n", __LINE__, function));
#endif
break;
}
return 0;
}
/*
* allocate a 'struct pmc_owner' descriptor in the owner hash table.
*/
static struct pmc_owner *
pmc_allocate_owner_descriptor(struct proc *p)
{
uint32_t hindex;
struct pmc_owner *po;
struct pmc_ownerhash *poh;
hindex = PMC_HASH_PTR(p, pmc_ownerhashmask);
poh = &pmc_ownerhash[hindex];
/* allocate space for N pointers and one descriptor struct */
po = malloc(sizeof(struct pmc_owner), M_PMC, M_WAITOK|M_ZERO);
po->po_sscount = po->po_error = po->po_flags = 0;
po->po_file = NULL;
po->po_owner = p;
po->po_kthread = NULL;
LIST_INIT(&po->po_pmcs);
LIST_INSERT_HEAD(poh, po, po_next); /* insert into hash table */
TAILQ_INIT(&po->po_logbuffers);
mtx_init(&po->po_mtx, "pmc-owner-mtx", "pmc-per-proc", MTX_SPIN);
PMCDBG(OWN,ALL,1, "allocate-owner proc=%p (%d, %s) pmc-owner=%p",
p, p->p_pid, p->p_comm, po);
return po;
}
static void
pmc_destroy_owner_descriptor(struct pmc_owner *po)
{
PMCDBG(OWN,REL,1, "destroy-owner po=%p proc=%p (%d, %s)",
po, po->po_owner, po->po_owner->p_pid, po->po_owner->p_comm);
mtx_destroy(&po->po_mtx);
free(po, M_PMC);
}
/*
* find the descriptor corresponding to process 'p', adding or removing it
* as specified by 'mode'.
*/
static struct pmc_process *
pmc_find_process_descriptor(struct proc *p, uint32_t mode)
{
uint32_t hindex;
struct pmc_process *pp, *ppnew;
struct pmc_processhash *pph;
hindex = PMC_HASH_PTR(p, pmc_processhashmask);
pph = &pmc_processhash[hindex];
ppnew = NULL;
/*
* Pre-allocate memory in the FIND_ALLOCATE case since we
* cannot call malloc(9) once we hold a spin lock.
*/
if (mode & PMC_FLAG_ALLOCATE)
ppnew = malloc(sizeof(struct pmc_process) + md->pmd_npmc *
sizeof(struct pmc_targetstate), M_PMC, M_WAITOK|M_ZERO);
mtx_lock_spin(&pmc_processhash_mtx);
LIST_FOREACH(pp, pph, pp_next)
if (pp->pp_proc == p)
break;
if ((mode & PMC_FLAG_REMOVE) && pp != NULL)
LIST_REMOVE(pp, pp_next);
if ((mode & PMC_FLAG_ALLOCATE) && pp == NULL &&
ppnew != NULL) {
ppnew->pp_proc = p;
LIST_INSERT_HEAD(pph, ppnew, pp_next);
pp = ppnew;
ppnew = NULL;
}
mtx_unlock_spin(&pmc_processhash_mtx);
if (pp != NULL && ppnew != NULL)
free(ppnew, M_PMC);
return pp;
}
/*
* remove a process descriptor from the process hash table.
*/
static void
pmc_remove_process_descriptor(struct pmc_process *pp)
{
KASSERT(pp->pp_refcnt == 0,
("[pmc,%d] Removing process descriptor %p with count %d",
__LINE__, pp, pp->pp_refcnt));
mtx_lock_spin(&pmc_processhash_mtx);
LIST_REMOVE(pp, pp_next);
mtx_unlock_spin(&pmc_processhash_mtx);
}
/*
* find an owner descriptor corresponding to proc 'p'
*/
static struct pmc_owner *
pmc_find_owner_descriptor(struct proc *p)
{
uint32_t hindex;
struct pmc_owner *po;
struct pmc_ownerhash *poh;
hindex = PMC_HASH_PTR(p, pmc_ownerhashmask);
poh = &pmc_ownerhash[hindex];
po = NULL;
LIST_FOREACH(po, poh, po_next)
if (po->po_owner == p)
break;
PMCDBG(OWN,FND,1, "find-owner proc=%p (%d, %s) hindex=0x%x -> "
"pmc-owner=%p", p, p->p_pid, p->p_comm, hindex, po);
return po;
}
/*
* pmc_allocate_pmc_descriptor
*
* Allocate a pmc descriptor and initialize its
* fields.
*/
static struct pmc *
pmc_allocate_pmc_descriptor(void)
{
struct pmc *pmc;
pmc = malloc(sizeof(struct pmc), M_PMC, M_WAITOK|M_ZERO);
if (pmc != NULL) {
pmc->pm_owner = NULL;
LIST_INIT(&pmc->pm_targets);
}
PMCDBG(PMC,ALL,1, "allocate-pmc -> pmc=%p", pmc);
return pmc;
}
/*
* Destroy a pmc descriptor.
*/
static void
pmc_destroy_pmc_descriptor(struct pmc *pm)
{
(void) pm;
#ifdef DEBUG
KASSERT(pm->pm_state == PMC_STATE_DELETED ||
pm->pm_state == PMC_STATE_FREE,
("[pmc,%d] destroying non-deleted PMC", __LINE__));
KASSERT(LIST_EMPTY(&pm->pm_targets),
("[pmc,%d] destroying pmc with targets", __LINE__));
KASSERT(pm->pm_owner == NULL,
("[pmc,%d] destroying pmc attached to an owner", __LINE__));
KASSERT(pm->pm_runcount == 0,
("[pmc,%d] pmc has non-zero run count %d", __LINE__,
pm->pm_runcount));
#endif
}
static void
pmc_wait_for_pmc_idle(struct pmc *pm)
{
#ifdef DEBUG
volatile int maxloop;
maxloop = 100 * pmc_cpu_max();
#endif
/*
* Loop (with a forced context switch) till the PMC's runcount
* comes down to zero.
*/
while (atomic_load_acq_32(&pm->pm_runcount) > 0) {
#ifdef DEBUG
maxloop--;
KASSERT(maxloop > 0,
("[pmc,%d] (ri%d, rc%d) waiting too long for "
"pmc to be free", __LINE__,
PMC_TO_ROWINDEX(pm), pm->pm_runcount));
#endif
pmc_force_context_switch();
}
}
/*
* This function does the following things:
*
* - detaches the PMC from hardware
* - unlinks all target threads that were attached to it
* - removes the PMC from its owner's list
* - destroy's the PMC private mutex
*
* Once this function completes, the given pmc pointer can be safely
* FREE'd by the caller.
*/
static void
pmc_release_pmc_descriptor(struct pmc *pm)
{
enum pmc_mode mode;
struct pmc_hw *phw;
u_int adjri, ri, cpu;
struct pmc_owner *po;
struct pmc_binding pb;
struct pmc_process *pp;
struct pmc_classdep *pcd;
struct pmc_target *ptgt, *tmp;
sx_assert(&pmc_sx, SX_XLOCKED);
KASSERT(pm, ("[pmc,%d] null pmc", __LINE__));
ri = PMC_TO_ROWINDEX(pm);
pcd = pmc_ri_to_classdep(md, ri, &adjri);
mode = PMC_TO_MODE(pm);
PMCDBG(PMC,REL,1, "release-pmc pmc=%p ri=%d mode=%d", pm, ri,
mode);
/*
* First, we take the PMC off hardware.
*/
cpu = 0;
if (PMC_IS_SYSTEM_MODE(mode)) {
/*
* A system mode PMC runs on a specific CPU. Switch
* to this CPU and turn hardware off.
*/
pmc_save_cpu_binding(&pb);
cpu = PMC_TO_CPU(pm);
pmc_select_cpu(cpu);
/* switch off non-stalled CPUs */
if (pm->pm_state == PMC_STATE_RUNNING &&
pm->pm_stalled == 0) {
phw = pmc_pcpu[cpu]->pc_hwpmcs[ri];
KASSERT(phw->phw_pmc == pm,
("[pmc, %d] pmc ptr ri(%d) hw(%p) pm(%p)",
__LINE__, ri, phw->phw_pmc, pm));
PMCDBG(PMC,REL,2, "stopping cpu=%d ri=%d", cpu, ri);
critical_enter();
pcd->pcd_stop_pmc(cpu, adjri);
critical_exit();
}
PMCDBG(PMC,REL,2, "decfg cpu=%d ri=%d", cpu, ri);
critical_enter();
pcd->pcd_config_pmc(cpu, adjri, NULL);
critical_exit();
/* adjust the global and process count of SS mode PMCs */
if (mode == PMC_MODE_SS && pm->pm_state == PMC_STATE_RUNNING) {
po = pm->pm_owner;
po->po_sscount--;
if (po->po_sscount == 0) {
atomic_subtract_rel_int(&pmc_ss_count, 1);
LIST_REMOVE(po, po_ssnext);
}
}
pm->pm_state = PMC_STATE_DELETED;
pmc_restore_cpu_binding(&pb);
/*
* We could have references to this PMC structure in
* the per-cpu sample queues. Wait for the queue to
* drain.
*/
pmc_wait_for_pmc_idle(pm);
} else if (PMC_IS_VIRTUAL_MODE(mode)) {
/*
* A virtual PMC could be running on multiple CPUs at
* a given instant.
*
* By marking its state as DELETED, we ensure that
* this PMC is never further scheduled on hardware.
*
* Then we wait till all CPUs are done with this PMC.
*/
pm->pm_state = PMC_STATE_DELETED;
/* Wait for the PMCs runcount to come to zero. */
pmc_wait_for_pmc_idle(pm);
/*
* At this point the PMC is off all CPUs and cannot be
* freshly scheduled onto a CPU. It is now safe to
* unlink all targets from this PMC. If a
* process-record's refcount falls to zero, we remove
* it from the hash table. The module-wide SX lock
* protects us from races.
*/
LIST_FOREACH_SAFE(ptgt, &pm->pm_targets, pt_next, tmp) {
pp = ptgt->pt_process;
pmc_unlink_target_process(pm, pp); /* frees 'ptgt' */
PMCDBG(PMC,REL,3, "pp->refcnt=%d", pp->pp_refcnt);
/*
* If the target process record shows that no
* PMCs are attached to it, reclaim its space.
*/
if (pp->pp_refcnt == 0) {
pmc_remove_process_descriptor(pp);
free(pp, M_PMC);
}
}
cpu = curthread->td_oncpu; /* setup cpu for pmd_release() */
}
/*
* Release any MD resources
*/
(void) pcd->pcd_release_pmc(cpu, adjri, pm);
/*
* Update row disposition
*/
if (PMC_IS_SYSTEM_MODE(PMC_TO_MODE(pm)))
PMC_UNMARK_ROW_STANDALONE(ri);
else
PMC_UNMARK_ROW_THREAD(ri);
/* unlink from the owner's list */
if (pm->pm_owner) {
LIST_REMOVE(pm, pm_next);
pm->pm_owner = NULL;
}
pmc_destroy_pmc_descriptor(pm);
}
/*
* Register an owner and a pmc.
*/
static int
pmc_register_owner(struct proc *p, struct pmc *pmc)
{
struct pmc_owner *po;
sx_assert(&pmc_sx, SX_XLOCKED);
if ((po = pmc_find_owner_descriptor(p)) == NULL)
if ((po = pmc_allocate_owner_descriptor(p)) == NULL)
return ENOMEM;
KASSERT(pmc->pm_owner == NULL,
("[pmc,%d] attempting to own an initialized PMC", __LINE__));
pmc->pm_owner = po;
LIST_INSERT_HEAD(&po->po_pmcs, pmc, pm_next);
PROC_LOCK(p);
p->p_flag |= P_HWPMC;
PROC_UNLOCK(p);
if (po->po_flags & PMC_PO_OWNS_LOGFILE)
pmclog_process_pmcallocate(pmc);
PMCDBG(PMC,REG,1, "register-owner pmc-owner=%p pmc=%p",
po, pmc);
return 0;
}
/*
* Return the current row disposition:
* == 0 => FREE
* > 0 => PROCESS MODE
* < 0 => SYSTEM MODE
*/
int
pmc_getrowdisp(int ri)
{
return pmc_pmcdisp[ri];
}
/*
* Check if a PMC at row index 'ri' can be allocated to the current
* process.
*
* Allocation can fail if:
* - the current process is already being profiled by a PMC at index 'ri',
* attached to it via OP_PMCATTACH.
* - the current process has already allocated a PMC at index 'ri'
* via OP_ALLOCATE.
*/
static int
pmc_can_allocate_rowindex(struct proc *p, unsigned int ri, int cpu)
{
enum pmc_mode mode;
struct pmc *pm;
struct pmc_owner *po;
struct pmc_process *pp;
PMCDBG(PMC,ALR,1, "can-allocate-rowindex proc=%p (%d, %s) ri=%d "
"cpu=%d", p, p->p_pid, p->p_comm, ri, cpu);
/*
* We shouldn't have already allocated a process-mode PMC at
* row index 'ri'.
*
* We shouldn't have allocated a system-wide PMC on the same
* CPU and same RI.
*/
if ((po = pmc_find_owner_descriptor(p)) != NULL)
LIST_FOREACH(pm, &po->po_pmcs, pm_next) {
if (PMC_TO_ROWINDEX(pm) == ri) {
mode = PMC_TO_MODE(pm);
if (PMC_IS_VIRTUAL_MODE(mode))
return EEXIST;
if (PMC_IS_SYSTEM_MODE(mode) &&
(int) PMC_TO_CPU(pm) == cpu)
return EEXIST;
}
}
/*
* We also shouldn't be the target of any PMC at this index
* since otherwise a PMC_ATTACH to ourselves will fail.
*/
if ((pp = pmc_find_process_descriptor(p, 0)) != NULL)
if (pp->pp_pmcs[ri].pp_pmc)
return EEXIST;
PMCDBG(PMC,ALR,2, "can-allocate-rowindex proc=%p (%d, %s) ri=%d ok",
p, p->p_pid, p->p_comm, ri);
return 0;
}
/*
* Check if a given PMC at row index 'ri' can be currently used in
* mode 'mode'.
*/
static int
pmc_can_allocate_row(int ri, enum pmc_mode mode)
{
enum pmc_disp disp;
sx_assert(&pmc_sx, SX_XLOCKED);
PMCDBG(PMC,ALR,1, "can-allocate-row ri=%d mode=%d", ri, mode);
if (PMC_IS_SYSTEM_MODE(mode))
disp = PMC_DISP_STANDALONE;
else
disp = PMC_DISP_THREAD;
/*
* check disposition for PMC row 'ri':
*
* Expected disposition Row-disposition Result
*
* STANDALONE STANDALONE or FREE proceed
* STANDALONE THREAD fail
* THREAD THREAD or FREE proceed
* THREAD STANDALONE fail
*/
if (!PMC_ROW_DISP_IS_FREE(ri) &&
!(disp == PMC_DISP_THREAD && PMC_ROW_DISP_IS_THREAD(ri)) &&
!(disp == PMC_DISP_STANDALONE && PMC_ROW_DISP_IS_STANDALONE(ri)))
return EBUSY;
/*
* All OK
*/
PMCDBG(PMC,ALR,2, "can-allocate-row ri=%d mode=%d ok", ri, mode);
return 0;
}
/*
* Find a PMC descriptor with user handle 'pmcid' for thread 'td'.
*/
static struct pmc *
pmc_find_pmc_descriptor_in_process(struct pmc_owner *po, pmc_id_t pmcid)
{
struct pmc *pm;
KASSERT(PMC_ID_TO_ROWINDEX(pmcid) < md->pmd_npmc,
("[pmc,%d] Illegal pmc index %d (max %d)", __LINE__,
PMC_ID_TO_ROWINDEX(pmcid), md->pmd_npmc));
LIST_FOREACH(pm, &po->po_pmcs, pm_next)
if (pm->pm_id == pmcid)
return pm;
return NULL;
}
static int
pmc_find_pmc(pmc_id_t pmcid, struct pmc **pmc)
{
struct pmc *pm;
struct pmc_owner *po;
PMCDBG(PMC,FND,1, "find-pmc id=%d", pmcid);
if ((po = pmc_find_owner_descriptor(curthread->td_proc)) == NULL)
return ESRCH;
if ((pm = pmc_find_pmc_descriptor_in_process(po, pmcid)) == NULL)
return EINVAL;
PMCDBG(PMC,FND,2, "find-pmc id=%d -> pmc=%p", pmcid, pm);
*pmc = pm;
return 0;
}
/*
* Start a PMC.
*/
static int
pmc_start(struct pmc *pm)
{
enum pmc_mode mode;
struct pmc_owner *po;
struct pmc_binding pb;
struct pmc_classdep *pcd;
int adjri, error, cpu, ri;
KASSERT(pm != NULL,
("[pmc,%d] null pm", __LINE__));
mode = PMC_TO_MODE(pm);
ri = PMC_TO_ROWINDEX(pm);
pcd = pmc_ri_to_classdep(md, ri, &adjri);
error = 0;
PMCDBG(PMC,OPS,1, "start pmc=%p mode=%d ri=%d", pm, mode, ri);
po = pm->pm_owner;
/*
* Disallow PMCSTART if a logfile is required but has not been
* configured yet.
*/
if ((pm->pm_flags & PMC_F_NEEDS_LOGFILE) &&
(po->po_flags & PMC_PO_OWNS_LOGFILE) == 0)
return (EDOOFUS); /* programming error */
/*
* If this is a sampling mode PMC, log mapping information for
* the kernel modules that are currently loaded.
*/
if (PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)))
pmc_log_kernel_mappings(pm);
if (PMC_IS_VIRTUAL_MODE(mode)) {
/*
* If a PMCATTACH has never been done on this PMC,
* attach it to its owner process.
*/
if (LIST_EMPTY(&pm->pm_targets))
error = (pm->pm_flags & PMC_F_ATTACH_DONE) ? ESRCH :
pmc_attach_process(po->po_owner, pm);
/*
* If the PMC is attached to its owner, then force a context
* switch to ensure that the MD state gets set correctly.
*/
if (error == 0) {
pm->pm_state = PMC_STATE_RUNNING;
if (pm->pm_flags & PMC_F_ATTACHED_TO_OWNER)
pmc_force_context_switch();
}
return (error);
}
/*
* A system-wide PMC.
*
* Add the owner to the global list if this is a system-wide
* sampling PMC.
*/
if (mode == PMC_MODE_SS) {
if (po->po_sscount == 0) {
LIST_INSERT_HEAD(&pmc_ss_owners, po, po_ssnext);
atomic_add_rel_int(&pmc_ss_count, 1);
PMCDBG(PMC,OPS,1, "po=%p in global list", po);
}
po->po_sscount++;
}
/* Log mapping information for all processes in the system. */
pmc_log_all_process_mappings(po);
/*
* Move to the CPU associated with this
* PMC, and start the hardware.
*/
pmc_save_cpu_binding(&pb);
cpu = PMC_TO_CPU(pm);
if (!pmc_cpu_is_active(cpu))
return (ENXIO);
pmc_select_cpu(cpu);
/*
* global PMCs are configured at allocation time
* so write out the initial value and start the PMC.
*/
pm->pm_state = PMC_STATE_RUNNING;
critical_enter();
if ((error = pcd->pcd_write_pmc(cpu, adjri,
PMC_IS_SAMPLING_MODE(mode) ?
pm->pm_sc.pm_reloadcount :
pm->pm_sc.pm_initial)) == 0)
error = pcd->pcd_start_pmc(cpu, adjri);
critical_exit();
pmc_restore_cpu_binding(&pb);
return (error);
}
/*
* Stop a PMC.
*/
static int
pmc_stop(struct pmc *pm)
{
struct pmc_owner *po;
struct pmc_binding pb;
struct pmc_classdep *pcd;
int adjri, cpu, error, ri;
KASSERT(pm != NULL, ("[pmc,%d] null pmc", __LINE__));
PMCDBG(PMC,OPS,1, "stop pmc=%p mode=%d ri=%d", pm,
PMC_TO_MODE(pm), PMC_TO_ROWINDEX(pm));
pm->pm_state = PMC_STATE_STOPPED;
/*
* If the PMC is a virtual mode one, changing the state to
* non-RUNNING is enough to ensure that the PMC never gets
* scheduled.
*
* If this PMC is current running on a CPU, then it will
* handled correctly at the time its target process is context
* switched out.
*/
if (PMC_IS_VIRTUAL_MODE(PMC_TO_MODE(pm)))
return 0;
/*
* A system-mode PMC. Move to the CPU associated with
* this PMC, and stop the hardware. We update the
* 'initial count' so that a subsequent PMCSTART will
* resume counting from the current hardware count.
*/
pmc_save_cpu_binding(&pb);
cpu = PMC_TO_CPU(pm);
KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
("[pmc,%d] illegal cpu=%d", __LINE__, cpu));
if (!pmc_cpu_is_active(cpu))
return ENXIO;
pmc_select_cpu(cpu);
ri = PMC_TO_ROWINDEX(pm);
pcd = pmc_ri_to_classdep(md, ri, &adjri);
critical_enter();
if ((error = pcd->pcd_stop_pmc(cpu, adjri)) == 0)
error = pcd->pcd_read_pmc(cpu, adjri, &pm->pm_sc.pm_initial);
critical_exit();
pmc_restore_cpu_binding(&pb);
po = pm->pm_owner;
/* remove this owner from the global list of SS PMC owners */
if (PMC_TO_MODE(pm) == PMC_MODE_SS) {
po->po_sscount--;
if (po->po_sscount == 0) {
atomic_subtract_rel_int(&pmc_ss_count, 1);
LIST_REMOVE(po, po_ssnext);
PMCDBG(PMC,OPS,2,"po=%p removed from global list", po);
}
}
return (error);
}
#ifdef DEBUG
static const char *pmc_op_to_name[] = {
#undef __PMC_OP
#define __PMC_OP(N, D) #N ,
__PMC_OPS()
NULL
};
#endif
/*
* The syscall interface
*/
#define PMC_GET_SX_XLOCK(...) do { \
sx_xlock(&pmc_sx); \
if (pmc_hook == NULL) { \
sx_xunlock(&pmc_sx); \
return __VA_ARGS__; \
} \
} while (0)
#define PMC_DOWNGRADE_SX() do { \
sx_downgrade(&pmc_sx); \
is_sx_downgraded = 1; \
} while (0)
static int
pmc_syscall_handler(struct thread *td, void *syscall_args)
{
int error, is_sx_downgraded, op;
struct pmc_syscall_args *c;
void *arg;
PMC_GET_SX_XLOCK(ENOSYS);
DROP_GIANT();
is_sx_downgraded = 0;
c = (struct pmc_syscall_args *) syscall_args;
op = c->pmop_code;
arg = c->pmop_data;
PMCDBG(MOD,PMS,1, "syscall op=%d \"%s\" arg=%p", op,
pmc_op_to_name[op], arg);
error = 0;
atomic_add_int(&pmc_stats.pm_syscalls, 1);
switch(op)
{
/*
* Configure a log file.
*
* XXX This OP will be reworked.
*/
case PMC_OP_CONFIGURELOG:
{
struct proc *p;
struct pmc *pm;
struct pmc_owner *po;
struct pmc_op_configurelog cl;
sx_assert(&pmc_sx, SX_XLOCKED);
if ((error = copyin(arg, &cl, sizeof(cl))) != 0)
break;
/* mark this process as owning a log file */
p = td->td_proc;
if ((po = pmc_find_owner_descriptor(p)) == NULL)
if ((po = pmc_allocate_owner_descriptor(p)) == NULL) {
error = ENOMEM;
break;
}
/*
* If a valid fd was passed in, try to configure that,
* otherwise if 'fd' was less than zero and there was
* a log file configured, flush its buffers and
* de-configure it.
*/
if (cl.pm_logfd >= 0)
error = pmclog_configure_log(md, po, cl.pm_logfd);
else if (po->po_flags & PMC_PO_OWNS_LOGFILE) {
pmclog_process_closelog(po);
error = pmclog_flush(po);
if (error == 0) {
LIST_FOREACH(pm, &po->po_pmcs, pm_next)
if (pm->pm_flags & PMC_F_NEEDS_LOGFILE &&
pm->pm_state == PMC_STATE_RUNNING)
pmc_stop(pm);
error = pmclog_deconfigure_log(po);
}
} else
error = EINVAL;
if (error)
break;
}
break;
/*
* Flush a log file.
*/
case PMC_OP_FLUSHLOG:
{
struct pmc_owner *po;
sx_assert(&pmc_sx, SX_XLOCKED);
if ((po = pmc_find_owner_descriptor(td->td_proc)) == NULL) {
error = EINVAL;
break;
}
error = pmclog_flush(po);
}
break;
/*
* Retrieve hardware configuration.
*/
case PMC_OP_GETCPUINFO: /* CPU information */
{
struct pmc_op_getcpuinfo gci;
struct pmc_classinfo *pci;
struct pmc_classdep *pcd;
int cl;
gci.pm_cputype = md->pmd_cputype;
gci.pm_ncpu = pmc_cpu_max();
gci.pm_npmc = md->pmd_npmc;
gci.pm_nclass = md->pmd_nclass;
pci = gci.pm_classes;
pcd = md->pmd_classdep;
for (cl = 0; cl < md->pmd_nclass; cl++, pci++, pcd++) {
pci->pm_caps = pcd->pcd_caps;
pci->pm_class = pcd->pcd_class;
pci->pm_width = pcd->pcd_width;
pci->pm_num = pcd->pcd_num;
}
error = copyout(&gci, arg, sizeof(gci));
}
break;
/*
* Get module statistics
*/
case PMC_OP_GETDRIVERSTATS:
{
struct pmc_op_getdriverstats gms;
bcopy(&pmc_stats, &gms, sizeof(gms));
error = copyout(&gms, arg, sizeof(gms));
}
break;
/*
* Retrieve module version number
*/
case PMC_OP_GETMODULEVERSION:
{
uint32_t cv, modv;
/* retrieve the client's idea of the ABI version */
if ((error = copyin(arg, &cv, sizeof(uint32_t))) != 0)
break;
/* don't service clients newer than our driver */
modv = PMC_VERSION;
if ((cv & 0xFFFF0000) > (modv & 0xFFFF0000)) {
error = EPROGMISMATCH;
break;
}
error = copyout(&modv, arg, sizeof(int));
}
break;
/*
* Retrieve the state of all the PMCs on a given
* CPU.
*/
case PMC_OP_GETPMCINFO:
{
int ari;
struct pmc *pm;
size_t pmcinfo_size;
uint32_t cpu, n, npmc;
struct pmc_owner *po;
struct pmc_binding pb;
struct pmc_classdep *pcd;
struct pmc_info *p, *pmcinfo;
struct pmc_op_getpmcinfo *gpi;
PMC_DOWNGRADE_SX();
gpi = (struct pmc_op_getpmcinfo *) arg;
if ((error = copyin(&gpi->pm_cpu, &cpu, sizeof(cpu))) != 0)
break;
if (cpu >= pmc_cpu_max()) {
error = EINVAL;
break;
}
if (!pmc_cpu_is_active(cpu)) {
error = ENXIO;
break;
}
/* switch to CPU 'cpu' */
pmc_save_cpu_binding(&pb);
pmc_select_cpu(cpu);
npmc = md->pmd_npmc;
pmcinfo_size = npmc * sizeof(struct pmc_info);
pmcinfo = malloc(pmcinfo_size, M_PMC, M_WAITOK);
p = pmcinfo;
for (n = 0; n < md->pmd_npmc; n++, p++) {
pcd = pmc_ri_to_classdep(md, n, &ari);
KASSERT(pcd != NULL,
("[pmc,%d] null pcd ri=%d", __LINE__, n));
if ((error = pcd->pcd_describe(cpu, ari, p, &pm)) != 0)
break;
if (PMC_ROW_DISP_IS_STANDALONE(n))
p->pm_rowdisp = PMC_DISP_STANDALONE;
else if (PMC_ROW_DISP_IS_THREAD(n))
p->pm_rowdisp = PMC_DISP_THREAD;
else
p->pm_rowdisp = PMC_DISP_FREE;
p->pm_ownerpid = -1;
if (pm == NULL) /* no PMC associated */
continue;
po = pm->pm_owner;
KASSERT(po->po_owner != NULL,
("[pmc,%d] pmc_owner had a null proc pointer",
__LINE__));
p->pm_ownerpid = po->po_owner->p_pid;
p->pm_mode = PMC_TO_MODE(pm);
p->pm_event = pm->pm_event;
p->pm_flags = pm->pm_flags;
if (PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)))
p->pm_reloadcount =
pm->pm_sc.pm_reloadcount;
}
pmc_restore_cpu_binding(&pb);
/* now copy out the PMC info collected */
if (error == 0)
error = copyout(pmcinfo, &gpi->pm_pmcs, pmcinfo_size);
free(pmcinfo, M_PMC);
}
break;
/*
* Set the administrative state of a PMC. I.e. whether
* the PMC is to be used or not.
*/
case PMC_OP_PMCADMIN:
{
int cpu, ri;
enum pmc_state request;
struct pmc_cpu *pc;
struct pmc_hw *phw;
struct pmc_op_pmcadmin pma;
struct pmc_binding pb;
sx_assert(&pmc_sx, SX_XLOCKED);
KASSERT(td == curthread,
("[pmc,%d] td != curthread", __LINE__));
error = priv_check(td, PRIV_PMC_MANAGE);
if (error)
break;
if ((error = copyin(arg, &pma, sizeof(pma))) != 0)
break;
cpu = pma.pm_cpu;
if (cpu < 0 || cpu >= (int) pmc_cpu_max()) {
error = EINVAL;
break;
}
if (!pmc_cpu_is_active(cpu)) {
error = ENXIO;
break;
}
request = pma.pm_state;
if (request != PMC_STATE_DISABLED &&
request != PMC_STATE_FREE) {
error = EINVAL;
break;
}
ri = pma.pm_pmc; /* pmc id == row index */
if (ri < 0 || ri >= (int) md->pmd_npmc) {
error = EINVAL;
break;
}
/*
* We can't disable a PMC with a row-index allocated
* for process virtual PMCs.
*/
if (PMC_ROW_DISP_IS_THREAD(ri) &&
request == PMC_STATE_DISABLED) {
error = EBUSY;
break;
}
/*
* otherwise, this PMC on this CPU is either free or
* in system-wide mode.
*/
pmc_save_cpu_binding(&pb);
pmc_select_cpu(cpu);
pc = pmc_pcpu[cpu];
phw = pc->pc_hwpmcs[ri];
/*
* XXX do we need some kind of 'forced' disable?
*/
if (phw->phw_pmc == NULL) {
if (request == PMC_STATE_DISABLED &&
(phw->phw_state & PMC_PHW_FLAG_IS_ENABLED)) {
phw->phw_state &= ~PMC_PHW_FLAG_IS_ENABLED;
PMC_MARK_ROW_STANDALONE(ri);
} else if (request == PMC_STATE_FREE &&
(phw->phw_state & PMC_PHW_FLAG_IS_ENABLED) == 0) {
phw->phw_state |= PMC_PHW_FLAG_IS_ENABLED;
PMC_UNMARK_ROW_STANDALONE(ri);
}
/* other cases are a no-op */
} else
error = EBUSY;
pmc_restore_cpu_binding(&pb);
}
break;
/*
* Allocate a PMC.
*/
case PMC_OP_PMCALLOCATE:
{
int adjri, n;
u_int cpu;
uint32_t caps;
struct pmc *pmc;
enum pmc_mode mode;
struct pmc_hw *phw;
struct pmc_binding pb;
struct pmc_classdep *pcd;
struct pmc_op_pmcallocate pa;
if ((error = copyin(arg, &pa, sizeof(pa))) != 0)
break;
caps = pa.pm_caps;
mode = pa.pm_mode;
cpu = pa.pm_cpu;
if ((mode != PMC_MODE_SS && mode != PMC_MODE_SC &&
mode != PMC_MODE_TS && mode != PMC_MODE_TC) ||
(cpu != (u_int) PMC_CPU_ANY && cpu >= pmc_cpu_max())) {
error = EINVAL;
break;
}
/*
* Virtual PMCs should only ask for a default CPU.
* System mode PMCs need to specify a non-default CPU.
*/
if ((PMC_IS_VIRTUAL_MODE(mode) && cpu != (u_int) PMC_CPU_ANY) ||
(PMC_IS_SYSTEM_MODE(mode) && cpu == (u_int) PMC_CPU_ANY)) {
error = EINVAL;
break;
}
/*
* Check that an inactive CPU is not being asked for.
*/
if (PMC_IS_SYSTEM_MODE(mode) && !pmc_cpu_is_active(cpu)) {
error = ENXIO;
break;
}
/*
* Refuse an allocation for a system-wide PMC if this
* process has been jailed, or if this process lacks
* super-user credentials and the sysctl tunable
* 'security.bsd.unprivileged_syspmcs' is zero.
*/
if (PMC_IS_SYSTEM_MODE(mode)) {
if (jailed(curthread->td_ucred)) {
error = EPERM;
break;
}
if (!pmc_unprivileged_syspmcs) {
error = priv_check(curthread,
PRIV_PMC_SYSTEM);
if (error)
break;
}
}
if (error)
break;
/*
* Look for valid values for 'pm_flags'
*/
if ((pa.pm_flags & ~(PMC_F_DESCENDANTS | PMC_F_LOG_PROCCSW |
PMC_F_LOG_PROCEXIT | PMC_F_CALLCHAIN)) != 0) {
error = EINVAL;
break;
}
/* process logging options are not allowed for system PMCs */
if (PMC_IS_SYSTEM_MODE(mode) && (pa.pm_flags &
(PMC_F_LOG_PROCCSW | PMC_F_LOG_PROCEXIT))) {
error = EINVAL;
break;
}
/*
* All sampling mode PMCs need to be able to interrupt the
* CPU.
*/
if (PMC_IS_SAMPLING_MODE(mode))
caps |= PMC_CAP_INTERRUPT;
/* A valid class specifier should have been passed in. */
for (n = 0; n < md->pmd_nclass; n++)
if (md->pmd_classdep[n].pcd_class == pa.pm_class)
break;
if (n == md->pmd_nclass) {
error = EINVAL;
break;
}
/* The requested PMC capabilities should be feasible. */
if ((md->pmd_classdep[n].pcd_caps & caps) != caps) {
error = EOPNOTSUPP;
break;
}
PMCDBG(PMC,ALL,2, "event=%d caps=0x%x mode=%d cpu=%d",
pa.pm_ev, caps, mode, cpu);
pmc = pmc_allocate_pmc_descriptor();
pmc->pm_id = PMC_ID_MAKE_ID(cpu,pa.pm_mode,pa.pm_class,
PMC_ID_INVALID);
pmc->pm_event = pa.pm_ev;
pmc->pm_state = PMC_STATE_FREE;
pmc->pm_caps = caps;
pmc->pm_flags = pa.pm_flags;
/* switch thread to CPU 'cpu' */
pmc_save_cpu_binding(&pb);
#define PMC_IS_SHAREABLE_PMC(cpu, n) \
(pmc_pcpu[(cpu)]->pc_hwpmcs[(n)]->phw_state & \
PMC_PHW_FLAG_IS_SHAREABLE)
#define PMC_IS_UNALLOCATED(cpu, n) \
(pmc_pcpu[(cpu)]->pc_hwpmcs[(n)]->phw_pmc == NULL)
if (PMC_IS_SYSTEM_MODE(mode)) {
pmc_select_cpu(cpu);
for (n = 0; n < (int) md->pmd_npmc; n++) {
pcd = pmc_ri_to_classdep(md, n, &adjri);
if (pmc_can_allocate_row(n, mode) == 0 &&
pmc_can_allocate_rowindex(
curthread->td_proc, n, cpu) == 0 &&
(PMC_IS_UNALLOCATED(cpu, n) ||
PMC_IS_SHAREABLE_PMC(cpu, n)) &&
pcd->pcd_allocate_pmc(cpu, adjri, pmc,
&pa) == 0)
break;
}
} else {
/* Process virtual mode */
for (n = 0; n < (int) md->pmd_npmc; n++) {
pcd = pmc_ri_to_classdep(md, n, &adjri);
if (pmc_can_allocate_row(n, mode) == 0 &&
pmc_can_allocate_rowindex(
curthread->td_proc, n,
PMC_CPU_ANY) == 0 &&
pcd->pcd_allocate_pmc(curthread->td_oncpu,
adjri, pmc, &pa) == 0)
break;
}
}
#undef PMC_IS_UNALLOCATED
#undef PMC_IS_SHAREABLE_PMC
pmc_restore_cpu_binding(&pb);
if (n == (int) md->pmd_npmc) {
pmc_destroy_pmc_descriptor(pmc);
free(pmc, M_PMC);
pmc = NULL;
error = EINVAL;
break;
}
/* Fill in the correct value in the ID field */
pmc->pm_id = PMC_ID_MAKE_ID(cpu,mode,pa.pm_class,n);
PMCDBG(PMC,ALL,2, "ev=%d class=%d mode=%d n=%d -> pmcid=%x",
pmc->pm_event, pa.pm_class, mode, n, pmc->pm_id);
/* Process mode PMCs with logging enabled need log files */
if (pmc->pm_flags & (PMC_F_LOG_PROCEXIT | PMC_F_LOG_PROCCSW))
pmc->pm_flags |= PMC_F_NEEDS_LOGFILE;
/* All system mode sampling PMCs require a log file */
if (PMC_IS_SAMPLING_MODE(mode) && PMC_IS_SYSTEM_MODE(mode))
pmc->pm_flags |= PMC_F_NEEDS_LOGFILE;
/*
* Configure global pmc's immediately
*/
if (PMC_IS_SYSTEM_MODE(PMC_TO_MODE(pmc))) {
pmc_save_cpu_binding(&pb);
pmc_select_cpu(cpu);
phw = pmc_pcpu[cpu]->pc_hwpmcs[n];
pcd = pmc_ri_to_classdep(md, n, &adjri);
if ((phw->phw_state & PMC_PHW_FLAG_IS_ENABLED) == 0 ||
(error = pcd->pcd_config_pmc(cpu, adjri, pmc)) != 0) {
(void) pcd->pcd_release_pmc(cpu, adjri, pmc);
pmc_destroy_pmc_descriptor(pmc);
free(pmc, M_PMC);
pmc = NULL;
pmc_restore_cpu_binding(&pb);
error = EPERM;
break;
}
pmc_restore_cpu_binding(&pb);
}
pmc->pm_state = PMC_STATE_ALLOCATED;
/*
* mark row disposition
*/
if (PMC_IS_SYSTEM_MODE(mode))
PMC_MARK_ROW_STANDALONE(n);
else
PMC_MARK_ROW_THREAD(n);
/*
* Register this PMC with the current thread as its owner.
*/
if ((error =
pmc_register_owner(curthread->td_proc, pmc)) != 0) {
pmc_release_pmc_descriptor(pmc);
free(pmc, M_PMC);
pmc = NULL;
break;
}
/*
* Return the allocated index.
*/
pa.pm_pmcid = pmc->pm_id;
error = copyout(&pa, arg, sizeof(pa));
}
break;
/*
* Attach a PMC to a process.
*/
case PMC_OP_PMCATTACH:
{
struct pmc *pm;
struct proc *p;
struct pmc_op_pmcattach a;
sx_assert(&pmc_sx, SX_XLOCKED);
if ((error = copyin(arg, &a, sizeof(a))) != 0)
break;
if (a.pm_pid < 0) {
error = EINVAL;
break;
} else if (a.pm_pid == 0)
a.pm_pid = td->td_proc->p_pid;
if ((error = pmc_find_pmc(a.pm_pmc, &pm)) != 0)
break;
if (PMC_IS_SYSTEM_MODE(PMC_TO_MODE(pm))) {
error = EINVAL;
break;
}
/* PMCs may be (re)attached only when allocated or stopped */
if (pm->pm_state == PMC_STATE_RUNNING) {
error = EBUSY;
break;
} else if (pm->pm_state != PMC_STATE_ALLOCATED &&
pm->pm_state != PMC_STATE_STOPPED) {
error = EINVAL;
break;
}
/* lookup pid */
if ((p = pfind(a.pm_pid)) == NULL) {
error = ESRCH;
break;
}
/*
* Ignore processes that are working on exiting.
*/
if (p->p_flag & P_WEXIT) {
error = ESRCH;
PROC_UNLOCK(p); /* pfind() returns a locked process */
break;
}
/*
* we are allowed to attach a PMC to a process if
* we can debug it.
*/
error = p_candebug(curthread, p);
PROC_UNLOCK(p);
if (error == 0)
error = pmc_attach_process(p, pm);
}
break;
/*
* Detach an attached PMC from a process.
*/
case PMC_OP_PMCDETACH:
{
struct pmc *pm;
struct proc *p;
struct pmc_op_pmcattach a;
if ((error = copyin(arg, &a, sizeof(a))) != 0)
break;
if (a.pm_pid < 0) {
error = EINVAL;
break;
} else if (a.pm_pid == 0)
a.pm_pid = td->td_proc->p_pid;
if ((error = pmc_find_pmc(a.pm_pmc, &pm)) != 0)
break;
if ((p = pfind(a.pm_pid)) == NULL) {
error = ESRCH;
break;
}
/*
* Treat processes that are in the process of exiting
* as if they were not present.
*/
if (p->p_flag & P_WEXIT)
error = ESRCH;
PROC_UNLOCK(p); /* pfind() returns a locked process */
if (error == 0)
error = pmc_detach_process(p, pm);
}
break;
/*
* Retrieve the MSR number associated with the counter
* 'pmc_id'. This allows processes to directly use RDPMC
* instructions to read their PMCs, without the overhead of a
* system call.
*/
case PMC_OP_PMCGETMSR:
{
int adjri, ri;
struct pmc *pm;
struct pmc_target *pt;
struct pmc_op_getmsr gm;
struct pmc_classdep *pcd;
PMC_DOWNGRADE_SX();
if ((error = copyin(arg, &gm, sizeof(gm))) != 0)
break;
if ((error = pmc_find_pmc(gm.pm_pmcid, &pm)) != 0)
break;
/*
* The allocated PMC has to be a process virtual PMC,
* i.e., of type MODE_T[CS]. Global PMCs can only be
* read using the PMCREAD operation since they may be
* allocated on a different CPU than the one we could
* be running on at the time of the RDPMC instruction.
*
* The GETMSR operation is not allowed for PMCs that
* are inherited across processes.
*/
if (!PMC_IS_VIRTUAL_MODE(PMC_TO_MODE(pm)) ||
(pm->pm_flags & PMC_F_DESCENDANTS)) {
error = EINVAL;
break;
}
/*
* It only makes sense to use a RDPMC (or its
* equivalent instruction on non-x86 architectures) on
* a process that has allocated and attached a PMC to
* itself. Conversely the PMC is only allowed to have
* one process attached to it -- its owner.
*/
if ((pt = LIST_FIRST(&pm->pm_targets)) == NULL ||
LIST_NEXT(pt, pt_next) != NULL ||
pt->pt_process->pp_proc != pm->pm_owner->po_owner) {
error = EINVAL;
break;
}
ri = PMC_TO_ROWINDEX(pm);
pcd = pmc_ri_to_classdep(md, ri, &adjri);
/* PMC class has no 'GETMSR' support */
if (pcd->pcd_get_msr == NULL) {
error = ENOSYS;
break;
}
if ((error = (*pcd->pcd_get_msr)(adjri, &gm.pm_msr)) < 0)
break;
if ((error = copyout(&gm, arg, sizeof(gm))) < 0)
break;
/*
* Mark our process as using MSRs. Update machine
* state using a forced context switch.
*/
pt->pt_process->pp_flags |= PMC_PP_ENABLE_MSR_ACCESS;
pmc_force_context_switch();
}
break;
/*
* Release an allocated PMC
*/
case PMC_OP_PMCRELEASE:
{
pmc_id_t pmcid;
struct pmc *pm;
struct pmc_owner *po;
struct pmc_op_simple sp;
/*
* Find PMC pointer for the named PMC.
*
* Use pmc_release_pmc_descriptor() to switch off the
* PMC, remove all its target threads, and remove the
* PMC from its owner's list.
*
* Remove the owner record if this is the last PMC
* owned.
*
* Free up space.
*/
if ((error = copyin(arg, &sp, sizeof(sp))) != 0)
break;
pmcid = sp.pm_pmcid;
if ((error = pmc_find_pmc(pmcid, &pm)) != 0)
break;
po = pm->pm_owner;
pmc_release_pmc_descriptor(pm);
pmc_maybe_remove_owner(po);
free(pm, M_PMC);
}
break;
/*
* Read and/or write a PMC.
*/
case PMC_OP_PMCRW:
{
int adjri;
struct pmc *pm;
uint32_t cpu, ri;
pmc_value_t oldvalue;
struct pmc_binding pb;
struct pmc_op_pmcrw prw;
struct pmc_classdep *pcd;
struct pmc_op_pmcrw *pprw;
PMC_DOWNGRADE_SX();
if ((error = copyin(arg, &prw, sizeof(prw))) != 0)
break;
ri = 0;
PMCDBG(PMC,OPS,1, "rw id=%d flags=0x%x", prw.pm_pmcid,
prw.pm_flags);
/* must have at least one flag set */
if ((prw.pm_flags & (PMC_F_OLDVALUE|PMC_F_NEWVALUE)) == 0) {
error = EINVAL;
break;
}
/* locate pmc descriptor */
if ((error = pmc_find_pmc(prw.pm_pmcid, &pm)) != 0)
break;
/* Can't read a PMC that hasn't been started. */
if (pm->pm_state != PMC_STATE_ALLOCATED &&
pm->pm_state != PMC_STATE_STOPPED &&
pm->pm_state != PMC_STATE_RUNNING) {
error = EINVAL;
break;
}
/* writing a new value is allowed only for 'STOPPED' pmcs */
if (pm->pm_state == PMC_STATE_RUNNING &&
(prw.pm_flags & PMC_F_NEWVALUE)) {
error = EBUSY;
break;
}
if (PMC_IS_VIRTUAL_MODE(PMC_TO_MODE(pm))) {
/*
* If this PMC is attached to its owner (i.e.,
* the process requesting this operation) and
* is running, then attempt to get an
* upto-date reading from hardware for a READ.
* Writes are only allowed when the PMC is
* stopped, so only update the saved value
* field.
*
* If the PMC is not running, or is not
* attached to its owner, read/write to the
* savedvalue field.
*/
ri = PMC_TO_ROWINDEX(pm);
pcd = pmc_ri_to_classdep(md, ri, &adjri);
mtx_pool_lock_spin(pmc_mtxpool, pm);
cpu = curthread->td_oncpu;
if (prw.pm_flags & PMC_F_OLDVALUE) {
if ((pm->pm_flags & PMC_F_ATTACHED_TO_OWNER) &&
(pm->pm_state == PMC_STATE_RUNNING))
error = (*pcd->pcd_read_pmc)(cpu, adjri,
&oldvalue);
else
oldvalue = pm->pm_gv.pm_savedvalue;
}
if (prw.pm_flags & PMC_F_NEWVALUE)
pm->pm_gv.pm_savedvalue = prw.pm_value;
mtx_pool_unlock_spin(pmc_mtxpool, pm);
} else { /* System mode PMCs */
cpu = PMC_TO_CPU(pm);
ri = PMC_TO_ROWINDEX(pm);
pcd = pmc_ri_to_classdep(md, ri, &adjri);
if (!pmc_cpu_is_active(cpu)) {
error = ENXIO;
break;
}
/* move this thread to CPU 'cpu' */
pmc_save_cpu_binding(&pb);
pmc_select_cpu(cpu);
critical_enter();
/* save old value */
if (prw.pm_flags & PMC_F_OLDVALUE)
if ((error = (*pcd->pcd_read_pmc)(cpu, adjri,
&oldvalue)))
goto error;
/* write out new value */
if (prw.pm_flags & PMC_F_NEWVALUE)
error = (*pcd->pcd_write_pmc)(cpu, adjri,
prw.pm_value);
error:
critical_exit();
pmc_restore_cpu_binding(&pb);
if (error)
break;
}
pprw = (struct pmc_op_pmcrw *) arg;
#ifdef DEBUG
if (prw.pm_flags & PMC_F_NEWVALUE)
PMCDBG(PMC,OPS,2, "rw id=%d new %jx -> old %jx",
ri, prw.pm_value, oldvalue);
else if (prw.pm_flags & PMC_F_OLDVALUE)
PMCDBG(PMC,OPS,2, "rw id=%d -> old %jx", ri, oldvalue);
#endif
/* return old value if requested */
if (prw.pm_flags & PMC_F_OLDVALUE)
if ((error = copyout(&oldvalue, &pprw->pm_value,
sizeof(prw.pm_value))))
break;
}
break;
/*
* Set the sampling rate for a sampling mode PMC and the
* initial count for a counting mode PMC.
*/
case PMC_OP_PMCSETCOUNT:
{
struct pmc *pm;
struct pmc_op_pmcsetcount sc;
PMC_DOWNGRADE_SX();
if ((error = copyin(arg, &sc, sizeof(sc))) != 0)
break;
if ((error = pmc_find_pmc(sc.pm_pmcid, &pm)) != 0)
break;
if (pm->pm_state == PMC_STATE_RUNNING) {
error = EBUSY;
break;
}
if (PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)))
pm->pm_sc.pm_reloadcount = sc.pm_count;
else
pm->pm_sc.pm_initial = sc.pm_count;
}
break;
/*
* Start a PMC.
*/
case PMC_OP_PMCSTART:
{
pmc_id_t pmcid;
struct pmc *pm;
struct pmc_op_simple sp;
sx_assert(&pmc_sx, SX_XLOCKED);
if ((error = copyin(arg, &sp, sizeof(sp))) != 0)
break;
pmcid = sp.pm_pmcid;
if ((error = pmc_find_pmc(pmcid, &pm)) != 0)
break;
KASSERT(pmcid == pm->pm_id,
("[pmc,%d] pmcid %x != id %x", __LINE__,
pm->pm_id, pmcid));
if (pm->pm_state == PMC_STATE_RUNNING) /* already running */
break;
else if (pm->pm_state != PMC_STATE_STOPPED &&
pm->pm_state != PMC_STATE_ALLOCATED) {
error = EINVAL;
break;
}
error = pmc_start(pm);
}
break;
/*
* Stop a PMC.
*/
case PMC_OP_PMCSTOP:
{
pmc_id_t pmcid;
struct pmc *pm;
struct pmc_op_simple sp;
PMC_DOWNGRADE_SX();
if ((error = copyin(arg, &sp, sizeof(sp))) != 0)
break;
pmcid = sp.pm_pmcid;
/*
* Mark the PMC as inactive and invoke the MD stop
* routines if needed.
*/
if ((error = pmc_find_pmc(pmcid, &pm)) != 0)
break;
KASSERT(pmcid == pm->pm_id,
("[pmc,%d] pmc id %x != pmcid %x", __LINE__,
pm->pm_id, pmcid));
if (pm->pm_state == PMC_STATE_STOPPED) /* already stopped */
break;
else if (pm->pm_state != PMC_STATE_RUNNING) {
error = EINVAL;
break;
}
error = pmc_stop(pm);
}
break;
/*
* Write a user supplied value to the log file.
*/
case PMC_OP_WRITELOG:
{
struct pmc_op_writelog wl;
struct pmc_owner *po;
PMC_DOWNGRADE_SX();
if ((error = copyin(arg, &wl, sizeof(wl))) != 0)
break;
if ((po = pmc_find_owner_descriptor(td->td_proc)) == NULL) {
error = EINVAL;
break;
}
if ((po->po_flags & PMC_PO_OWNS_LOGFILE) == 0) {
error = EINVAL;
break;
}
error = pmclog_process_userlog(po, &wl);
}
break;
default:
error = EINVAL;
break;
}
if (is_sx_downgraded)
sx_sunlock(&pmc_sx);
else
sx_xunlock(&pmc_sx);
if (error)
atomic_add_int(&pmc_stats.pm_syscall_errors, 1);
PICKUP_GIANT();
return error;
}
/*
* Helper functions
*/
/*
* Mark the thread as needing callchain capture and post an AST. The
* actual callchain capture will be done in a context where it is safe
* to take page faults.
*/
static void
pmc_post_callchain_callback(void)
{
struct thread *td;
td = curthread;
KASSERT((td->td_pflags & TDP_CALLCHAIN) == 0,
("[pmc,%d] thread %p already marked for callchain capture",
__LINE__, (void *) td));
/*
* Mark this thread as needing callchain capture.
* `td->td_pflags' will be safe to touch because this thread
* was in user space when it was interrupted.
*/
td->td_pflags |= TDP_CALLCHAIN;
/*
* Don't let this thread migrate between CPUs until callchain
* capture completes.
*/
sched_pin();
return;
}
/*
* Interrupt processing.
*
* Find a free slot in the per-cpu array of samples and capture the
* current callchain there. If a sample was successfully added, a bit
* is set in mask 'pmc_cpumask' denoting that the DO_SAMPLES hook
* needs to be invoked from the clock handler.
*
* This function is meant to be called from an NMI handler. It cannot
* use any of the locking primitives supplied by the OS.
*/
int
pmc_process_interrupt(int cpu, struct pmc *pm, struct trapframe *tf,
int inuserspace)
{
int error, callchaindepth;
struct thread *td;
struct pmc_sample *ps;
struct pmc_samplebuffer *psb;
error = 0;
/*
* Allocate space for a sample buffer.
*/
psb = pmc_pcpu[cpu]->pc_sb;
ps = psb->ps_write;
if (ps->ps_nsamples) { /* in use, reader hasn't caught up */
pm->pm_stalled = 1;
atomic_add_int(&pmc_stats.pm_intr_bufferfull, 1);
PMCDBG(SAM,INT,1,"(spc) cpu=%d pm=%p tf=%p um=%d wr=%d rd=%d",
cpu, pm, (void *) tf, inuserspace,
(int) (psb->ps_write - psb->ps_samples),
(int) (psb->ps_read - psb->ps_samples));
error = ENOMEM;
goto done;
}
/* Fill in entry. */
PMCDBG(SAM,INT,1,"cpu=%d pm=%p tf=%p um=%d wr=%d rd=%d", cpu, pm,
(void *) tf, inuserspace,
(int) (psb->ps_write - psb->ps_samples),
(int) (psb->ps_read - psb->ps_samples));
KASSERT(pm->pm_runcount >= 0,
("[pmc,%d] pm=%p runcount %d", __LINE__, (void *) pm,
pm->pm_runcount));
atomic_add_rel_32(&pm->pm_runcount, 1); /* hold onto PMC */
ps->ps_pmc = pm;
if ((td = curthread) && td->td_proc)
ps->ps_pid = td->td_proc->p_pid;
else
ps->ps_pid = -1;
ps->ps_cpu = cpu;
ps->ps_td = td;
ps->ps_flags = inuserspace ? PMC_CC_F_USERSPACE : 0;
callchaindepth = (pm->pm_flags & PMC_F_CALLCHAIN) ?
pmc_callchaindepth : 1;
if (callchaindepth == 1)
ps->ps_pc[0] = PMC_TRAPFRAME_TO_PC(tf);
else {
/*
* Kernel stack traversals can be done immediately,
* while we defer to an AST for user space traversals.
*/
if (!inuserspace)
callchaindepth =
pmc_save_kernel_callchain(ps->ps_pc,
callchaindepth, tf);
else {
pmc_post_callchain_callback();
callchaindepth = PMC_SAMPLE_INUSE;
}
}
ps->ps_nsamples = callchaindepth; /* mark entry as in use */
/* increment write pointer, modulo ring buffer size */
ps++;
if (ps == psb->ps_fence)
psb->ps_write = psb->ps_samples;
else
psb->ps_write = ps;
done:
/* mark CPU as needing processing */
atomic_set_rel_int(&pmc_cpumask, (1 << cpu));
return (error);
}
/*
* Capture a user call chain. This function will be called from ast()
* before control returns to userland and before the process gets
* rescheduled.
*/
static void
pmc_capture_user_callchain(int cpu, struct trapframe *tf)
{
int i;
struct pmc *pm;
struct thread *td;
struct pmc_sample *ps;
struct pmc_samplebuffer *psb;
#ifdef INVARIANTS
int ncallchains;
#endif
sched_unpin(); /* Can migrate safely now. */
psb = pmc_pcpu[cpu]->pc_sb;
td = curthread;
KASSERT(td->td_pflags & TDP_CALLCHAIN,
("[pmc,%d] Retrieving callchain for thread that doesn't want it",
__LINE__));
#ifdef INVARIANTS
ncallchains = 0;
#endif
/*
* Iterate through all deferred callchain requests.
*/
ps = psb->ps_samples;
for (i = 0; i < pmc_nsamples; i++, ps++) {
if (ps->ps_nsamples != PMC_SAMPLE_INUSE)
continue;
if (ps->ps_td != td)
continue;
KASSERT(ps->ps_cpu == cpu,
("[pmc,%d] cpu mismatch ps_cpu=%d pcpu=%d", __LINE__,
ps->ps_cpu, PCPU_GET(cpuid)));
pm = ps->ps_pmc;
KASSERT(pm->pm_flags & PMC_F_CALLCHAIN,
("[pmc,%d] Retrieving callchain for PMC that doesn't "
"want it", __LINE__));
KASSERT(pm->pm_runcount > 0,
("[pmc,%d] runcount %d", __LINE__, pm->pm_runcount));
/*
* Retrieve the callchain and mark the sample buffer
* as 'processable' by the timer tick sweep code.
*/
ps->ps_nsamples = pmc_save_user_callchain(ps->ps_pc,
pmc_callchaindepth, tf);
#ifdef INVARIANTS
ncallchains++;
#endif
}
KASSERT(ncallchains > 0,
("[pmc,%d] cpu %d didn't find a sample to collect", __LINE__,
cpu));
return;
}
/*
* Process saved PC samples.
*/
static void
pmc_process_samples(int cpu)
{
struct pmc *pm;
int adjri, n;
struct thread *td;
struct pmc_owner *po;
struct pmc_sample *ps;
struct pmc_classdep *pcd;
struct pmc_samplebuffer *psb;
KASSERT(PCPU_GET(cpuid) == cpu,
("[pmc,%d] not on the correct CPU pcpu=%d cpu=%d", __LINE__,
PCPU_GET(cpuid), cpu));
psb = pmc_pcpu[cpu]->pc_sb;
for (n = 0; n < pmc_nsamples; n++) { /* bound on #iterations */
ps = psb->ps_read;
if (ps->ps_nsamples == PMC_SAMPLE_FREE)
break;
if (ps->ps_nsamples == PMC_SAMPLE_INUSE) {
/* Need a rescan at a later time. */
atomic_set_rel_int(&pmc_cpumask, (1 << cpu));
break;
}
pm = ps->ps_pmc;
KASSERT(pm->pm_runcount > 0,
("[pmc,%d] pm=%p runcount %d", __LINE__, (void *) pm,
pm->pm_runcount));
po = pm->pm_owner;
KASSERT(PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)),
("[pmc,%d] pmc=%p non-sampling mode=%d", __LINE__,
pm, PMC_TO_MODE(pm)));
/* Ignore PMCs that have been switched off */
if (pm->pm_state != PMC_STATE_RUNNING)
goto entrydone;
PMCDBG(SAM,OPS,1,"cpu=%d pm=%p n=%d fl=%x wr=%d rd=%d", cpu,
pm, ps->ps_nsamples, ps->ps_flags,
(int) (psb->ps_write - psb->ps_samples),
(int) (psb->ps_read - psb->ps_samples));
/*
* If this is a process-mode PMC that is attached to
* its owner, and if the PC is in user mode, update
* profiling statistics like timer-based profiling
* would have done.
*/
if (pm->pm_flags & PMC_F_ATTACHED_TO_OWNER) {
if (ps->ps_flags & PMC_CC_F_USERSPACE) {
td = FIRST_THREAD_IN_PROC(po->po_owner);
addupc_intr(td, ps->ps_pc[0], 1);
}
goto entrydone;
}
/*
* Otherwise, this is either a sampling mode PMC that
* is attached to a different process than its owner,
* or a system-wide sampling PMC. Dispatch a log
* entry to the PMC's owner process.
*/
pmclog_process_callchain(pm, ps);
entrydone:
ps->ps_nsamples = 0; /* mark entry as free */
atomic_subtract_rel_32(&pm->pm_runcount, 1);
/* increment read pointer, modulo sample size */
if (++ps == psb->ps_fence)
psb->ps_read = psb->ps_samples;
else
psb->ps_read = ps;
}
atomic_add_int(&pmc_stats.pm_log_sweeps, 1);
/* Do not re-enable stalled PMCs if we failed to process any samples */
if (n == 0)
return;
/*
* Restart any stalled sampling PMCs on this CPU.
*
* If the NMI handler sets the pm_stalled field of a PMC after
* the check below, we'll end up processing the stalled PMC at
* the next hardclock tick.
*/
for (n = 0; n < md->pmd_npmc; n++) {
pcd = pmc_ri_to_classdep(md, n, &adjri);
KASSERT(pcd != NULL,
("[pmc,%d] null pcd ri=%d", __LINE__, n));
(void) (*pcd->pcd_get_config)(cpu,adjri,&pm);
if (pm == NULL || /* !cfg'ed */
pm->pm_state != PMC_STATE_RUNNING || /* !active */
!PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)) || /* !sampling */
pm->pm_stalled == 0) /* !stalled */
continue;
pm->pm_stalled = 0;
(*pcd->pcd_start_pmc)(cpu, adjri);
}
}
/*
* Event handlers.
*/
/*
* Handle a process exit.
*
* Remove this process from all hash tables. If this process
* owned any PMCs, turn off those PMCs and deallocate them,
* removing any associations with target processes.
*
* This function will be called by the last 'thread' of a
* process.
*
* XXX This eventhandler gets called early in the exit process.
* Consider using a 'hook' invocation from thread_exit() or equivalent
* spot. Another negative is that kse_exit doesn't seem to call
* exit1() [??].
*
*/
static void
pmc_process_exit(void *arg __unused, struct proc *p)
{
struct pmc *pm;
int adjri, cpu;
unsigned int ri;
int is_using_hwpmcs;
struct pmc_owner *po;
struct pmc_process *pp;
struct pmc_classdep *pcd;
pmc_value_t newvalue, tmp;
PROC_LOCK(p);
is_using_hwpmcs = p->p_flag & P_HWPMC;
PROC_UNLOCK(p);
/*
* Log a sysexit event to all SS PMC owners.
*/
LIST_FOREACH(po, &pmc_ss_owners, po_ssnext)
if (po->po_flags & PMC_PO_OWNS_LOGFILE)
pmclog_process_sysexit(po, p->p_pid);
if (!is_using_hwpmcs)
return;
PMC_GET_SX_XLOCK();
PMCDBG(PRC,EXT,1,"process-exit proc=%p (%d, %s)", p, p->p_pid,
p->p_comm);
/*
* Since this code is invoked by the last thread in an exiting
* process, we would have context switched IN at some prior
* point. However, with PREEMPTION, kernel mode context
* switches may happen any time, so we want to disable a
* context switch OUT till we get any PMCs targetting this
* process off the hardware.
*
* We also need to atomically remove this process'
* entry from our target process hash table, using
* PMC_FLAG_REMOVE.
*/
PMCDBG(PRC,EXT,1, "process-exit proc=%p (%d, %s)", p, p->p_pid,
p->p_comm);
critical_enter(); /* no preemption */
cpu = curthread->td_oncpu;
if ((pp = pmc_find_process_descriptor(p,
PMC_FLAG_REMOVE)) != NULL) {
PMCDBG(PRC,EXT,2,
"process-exit proc=%p pmc-process=%p", p, pp);
/*
* The exiting process could the target of
* some PMCs which will be running on
* currently executing CPU.
*
* We need to turn these PMCs off like we
* would do at context switch OUT time.
*/
for (ri = 0; ri < md->pmd_npmc; ri++) {
/*
* Pick up the pmc pointer from hardware
* state similar to the CSW_OUT code.
*/
pm = NULL;
pcd = pmc_ri_to_classdep(md, ri, &adjri);
(void) (*pcd->pcd_get_config)(cpu, adjri, &pm);
PMCDBG(PRC,EXT,2, "ri=%d pm=%p", ri, pm);
if (pm == NULL ||
!PMC_IS_VIRTUAL_MODE(PMC_TO_MODE(pm)))
continue;
PMCDBG(PRC,EXT,2, "ppmcs[%d]=%p pm=%p "
"state=%d", ri, pp->pp_pmcs[ri].pp_pmc,
pm, pm->pm_state);
KASSERT(PMC_TO_ROWINDEX(pm) == ri,
("[pmc,%d] ri mismatch pmc(%d) ri(%d)",
__LINE__, PMC_TO_ROWINDEX(pm), ri));
KASSERT(pm == pp->pp_pmcs[ri].pp_pmc,
("[pmc,%d] pm %p != pp_pmcs[%d] %p",
__LINE__, pm, ri, pp->pp_pmcs[ri].pp_pmc));
(void) pcd->pcd_stop_pmc(cpu, adjri);
KASSERT(pm->pm_runcount > 0,
("[pmc,%d] bad runcount ri %d rc %d",
__LINE__, ri, pm->pm_runcount));
/* Stop hardware only if it is actually running */
if (pm->pm_state == PMC_STATE_RUNNING &&
pm->pm_stalled == 0) {
pcd->pcd_read_pmc(cpu, adjri, &newvalue);
tmp = newvalue -
PMC_PCPU_SAVED(cpu,ri);
mtx_pool_lock_spin(pmc_mtxpool, pm);
pm->pm_gv.pm_savedvalue += tmp;
pp->pp_pmcs[ri].pp_pmcval += tmp;
mtx_pool_unlock_spin(pmc_mtxpool, pm);
}
atomic_subtract_rel_32(&pm->pm_runcount,1);
KASSERT((int) pm->pm_runcount >= 0,
("[pmc,%d] runcount is %d", __LINE__, ri));
(void) pcd->pcd_config_pmc(cpu, adjri, NULL);
}
/*
* Inform the MD layer of this pseudo "context switch
* out"
*/
(void) md->pmd_switch_out(pmc_pcpu[cpu], pp);
critical_exit(); /* ok to be pre-empted now */
/*
* Unlink this process from the PMCs that are
* targetting it. This will send a signal to
* all PMC owner's whose PMCs are orphaned.
*
* Log PMC value at exit time if requested.
*/
for (ri = 0; ri < md->pmd_npmc; ri++)
if ((pm = pp->pp_pmcs[ri].pp_pmc) != NULL) {
if (pm->pm_flags & PMC_F_NEEDS_LOGFILE &&
PMC_IS_COUNTING_MODE(PMC_TO_MODE(pm)))
pmclog_process_procexit(pm, pp);
pmc_unlink_target_process(pm, pp);
}
free(pp, M_PMC);
} else
critical_exit(); /* pp == NULL */
/*
* If the process owned PMCs, free them up and free up
* memory.
*/
if ((po = pmc_find_owner_descriptor(p)) != NULL) {
pmc_remove_owner(po);
pmc_destroy_owner_descriptor(po);
}
sx_xunlock(&pmc_sx);
}
/*
* Handle a process fork.
*
* If the parent process 'p1' is under HWPMC monitoring, then copy
* over any attached PMCs that have 'do_descendants' semantics.
*/
static void
pmc_process_fork(void *arg __unused, struct proc *p1, struct proc *newproc,
int flags)
{
int is_using_hwpmcs;
unsigned int ri;
uint32_t do_descendants;
struct pmc *pm;
struct pmc_owner *po;
struct pmc_process *ppnew, *ppold;
(void) flags; /* unused parameter */
PROC_LOCK(p1);
is_using_hwpmcs = p1->p_flag & P_HWPMC;
PROC_UNLOCK(p1);
/*
* If there are system-wide sampling PMCs active, we need to
* log all fork events to their owner's logs.
*/
LIST_FOREACH(po, &pmc_ss_owners, po_ssnext)
if (po->po_flags & PMC_PO_OWNS_LOGFILE)
pmclog_process_procfork(po, p1->p_pid, newproc->p_pid);
if (!is_using_hwpmcs)
return;
PMC_GET_SX_XLOCK();
PMCDBG(PMC,FRK,1, "process-fork proc=%p (%d, %s) -> %p", p1,
p1->p_pid, p1->p_comm, newproc);
/*
* If the parent process (curthread->td_proc) is a
* target of any PMCs, look for PMCs that are to be
* inherited, and link these into the new process
* descriptor.
*/
if ((ppold = pmc_find_process_descriptor(curthread->td_proc,
PMC_FLAG_NONE)) == NULL)
goto done; /* nothing to do */
do_descendants = 0;
for (ri = 0; ri < md->pmd_npmc; ri++)
if ((pm = ppold->pp_pmcs[ri].pp_pmc) != NULL)
do_descendants |= pm->pm_flags & PMC_F_DESCENDANTS;
if (do_descendants == 0) /* nothing to do */
goto done;
/* allocate a descriptor for the new process */
if ((ppnew = pmc_find_process_descriptor(newproc,
PMC_FLAG_ALLOCATE)) == NULL)
goto done;
/*
* Run through all PMCs that were targeting the old process
* and which specified F_DESCENDANTS and attach them to the
* new process.
*
* Log the fork event to all owners of PMCs attached to this
* process, if not already logged.
*/
for (ri = 0; ri < md->pmd_npmc; ri++)
if ((pm = ppold->pp_pmcs[ri].pp_pmc) != NULL &&
(pm->pm_flags & PMC_F_DESCENDANTS)) {
pmc_link_target_process(pm, ppnew);
po = pm->pm_owner;
if (po->po_sscount == 0 &&
po->po_flags & PMC_PO_OWNS_LOGFILE)
pmclog_process_procfork(po, p1->p_pid,
newproc->p_pid);
}
/*
* Now mark the new process as being tracked by this driver.
*/
PROC_LOCK(newproc);
newproc->p_flag |= P_HWPMC;
PROC_UNLOCK(newproc);
done:
sx_xunlock(&pmc_sx);
}
/*
* initialization
*/
static const char *pmc_name_of_pmcclass[] = {
#undef __PMC_CLASS
#define __PMC_CLASS(N) #N ,
__PMC_CLASSES()
};
static int
pmc_initialize(void)
{
int c, cpu, error, n, ri;
unsigned int maxcpu;
struct pmc_binding pb;
struct pmc_sample *ps;
struct pmc_classdep *pcd;
struct pmc_samplebuffer *sb;
md = NULL;
error = 0;
#ifdef DEBUG
/* parse debug flags first */
if (TUNABLE_STR_FETCH(PMC_SYSCTL_NAME_PREFIX "debugflags",
pmc_debugstr, sizeof(pmc_debugstr)))
pmc_debugflags_parse(pmc_debugstr,
pmc_debugstr+strlen(pmc_debugstr));
#endif
PMCDBG(MOD,INI,0, "PMC Initialize (version %x)", PMC_VERSION);
/* check kernel version */
if (pmc_kernel_version != PMC_VERSION) {
if (pmc_kernel_version == 0)
printf("hwpmc: this kernel has not been compiled with "
"'options HWPMC_HOOKS'.\n");
else
printf("hwpmc: kernel version (0x%x) does not match "
"module version (0x%x).\n", pmc_kernel_version,
PMC_VERSION);
return EPROGMISMATCH;
}
/*
* check sysctl parameters
*/
if (pmc_hashsize <= 0) {
(void) printf("hwpmc: tunable \"hashsize\"=%d must be "
"greater than zero.\n", pmc_hashsize);
pmc_hashsize = PMC_HASH_SIZE;
}
if (pmc_nsamples <= 0 || pmc_nsamples > 65535) {
(void) printf("hwpmc: tunable \"nsamples\"=%d out of "
"range.\n", pmc_nsamples);
pmc_nsamples = PMC_NSAMPLES;
}
if (pmc_callchaindepth <= 0 ||
pmc_callchaindepth > PMC_CALLCHAIN_DEPTH_MAX) {
(void) printf("hwpmc: tunable \"callchaindepth\"=%d out of "
"range.\n", pmc_callchaindepth);
pmc_callchaindepth = PMC_CALLCHAIN_DEPTH;
}
md = pmc_md_initialize();
if (md == NULL)
return (ENOSYS);
KASSERT(md->pmd_nclass >= 1 && md->pmd_npmc >= 1,
("[pmc,%d] no classes or pmcs", __LINE__));
/* Compute the map from row-indices to classdep pointers. */
pmc_rowindex_to_classdep = malloc(sizeof(struct pmc_classdep *) *
md->pmd_npmc, M_PMC, M_WAITOK|M_ZERO);
for (n = 0; n < md->pmd_npmc; n++)
pmc_rowindex_to_classdep[n] = NULL;
for (ri = c = 0; c < md->pmd_nclass; c++) {
pcd = &md->pmd_classdep[c];
for (n = 0; n < pcd->pcd_num; n++, ri++)
pmc_rowindex_to_classdep[ri] = pcd;
}
KASSERT(ri == md->pmd_npmc,
("[pmc,%d] npmc miscomputed: ri=%d, md->npmc=%d", __LINE__,
ri, md->pmd_npmc));
maxcpu = pmc_cpu_max();
/* allocate space for the per-cpu array */
pmc_pcpu = malloc(maxcpu * sizeof(struct pmc_cpu *), M_PMC,
M_WAITOK|M_ZERO);
/* per-cpu 'saved values' for managing process-mode PMCs */
pmc_pcpu_saved = malloc(sizeof(pmc_value_t) * maxcpu * md->pmd_npmc,
M_PMC, M_WAITOK);
/* Perform CPU-dependent initialization. */
pmc_save_cpu_binding(&pb);
error = 0;
for (cpu = 0; error == 0 && cpu < maxcpu; cpu++) {
if (!pmc_cpu_is_active(cpu))
continue;
pmc_select_cpu(cpu);
pmc_pcpu[cpu] = malloc(sizeof(struct pmc_cpu) +
md->pmd_npmc * sizeof(struct pmc_hw *), M_PMC,
M_WAITOK|M_ZERO);
if (md->pmd_pcpu_init)
error = md->pmd_pcpu_init(md, cpu);
for (n = 0; error == 0 && n < md->pmd_nclass; n++)
error = md->pmd_classdep[n].pcd_pcpu_init(md, cpu);
}
pmc_restore_cpu_binding(&pb);
if (error)
return (error);
/* allocate space for the sample array */
for (cpu = 0; cpu < maxcpu; cpu++) {
if (!pmc_cpu_is_active(cpu))
continue;
sb = malloc(sizeof(struct pmc_samplebuffer) +
pmc_nsamples * sizeof(struct pmc_sample), M_PMC,
M_WAITOK|M_ZERO);
sb->ps_read = sb->ps_write = sb->ps_samples;
sb->ps_fence = sb->ps_samples + pmc_nsamples;
KASSERT(pmc_pcpu[cpu] != NULL,
("[pmc,%d] cpu=%d Null per-cpu data", __LINE__, cpu));
sb->ps_callchains = malloc(pmc_callchaindepth * pmc_nsamples *
sizeof(uintptr_t), M_PMC, M_WAITOK|M_ZERO);
for (n = 0, ps = sb->ps_samples; n < pmc_nsamples; n++, ps++)
ps->ps_pc = sb->ps_callchains +
(n * pmc_callchaindepth);
pmc_pcpu[cpu]->pc_sb = sb;
}
/* allocate space for the row disposition array */
pmc_pmcdisp = malloc(sizeof(enum pmc_mode) * md->pmd_npmc,
M_PMC, M_WAITOK|M_ZERO);
KASSERT(pmc_pmcdisp != NULL,
("[pmc,%d] pmcdisp allocation returned NULL", __LINE__));
/* mark all PMCs as available */
for (n = 0; n < (int) md->pmd_npmc; n++)
PMC_MARK_ROW_FREE(n);
/* allocate thread hash tables */
pmc_ownerhash = hashinit(pmc_hashsize, M_PMC,
&pmc_ownerhashmask);
pmc_processhash = hashinit(pmc_hashsize, M_PMC,
&pmc_processhashmask);
mtx_init(&pmc_processhash_mtx, "pmc-process-hash", "pmc-leaf",
MTX_SPIN);
LIST_INIT(&pmc_ss_owners);
pmc_ss_count = 0;
/* allocate a pool of spin mutexes */
pmc_mtxpool = mtx_pool_create("pmc-leaf", pmc_mtxpool_size,
MTX_SPIN);
PMCDBG(MOD,INI,1, "pmc_ownerhash=%p, mask=0x%lx "
"targethash=%p mask=0x%lx", pmc_ownerhash, pmc_ownerhashmask,
pmc_processhash, pmc_processhashmask);
/* register process {exit,fork,exec} handlers */
pmc_exit_tag = EVENTHANDLER_REGISTER(process_exit,
pmc_process_exit, NULL, EVENTHANDLER_PRI_ANY);
pmc_fork_tag = EVENTHANDLER_REGISTER(process_fork,
pmc_process_fork, NULL, EVENTHANDLER_PRI_ANY);
/* initialize logging */
pmclog_initialize();
/* set hook functions */
pmc_intr = md->pmd_intr;
pmc_hook = pmc_hook_handler;
if (error == 0) {
printf(PMC_MODULE_NAME ":");
for (n = 0; n < (int) md->pmd_nclass; n++) {
pcd = &md->pmd_classdep[n];
printf(" %s/%d/%d/0x%b",
pmc_name_of_pmcclass[pcd->pcd_class],
pcd->pcd_num,
pcd->pcd_width,
pcd->pcd_caps,
"\20"
"\1INT\2USR\3SYS\4EDG\5THR"
"\6REA\7WRI\10INV\11QUA\12PRC"
"\13TAG\14CSC");
}
printf("\n");
}
return (error);
}
/* prepare to be unloaded */
static void
pmc_cleanup(void)
{
int c, cpu;
unsigned int maxcpu;
struct pmc_ownerhash *ph;
struct pmc_owner *po, *tmp;
struct pmc_binding pb;
#ifdef DEBUG
struct pmc_processhash *prh;
#endif
PMCDBG(MOD,INI,0, "%s", "cleanup");
/* switch off sampling */
atomic_store_rel_int(&pmc_cpumask, 0);
pmc_intr = NULL;
sx_xlock(&pmc_sx);
if (pmc_hook == NULL) { /* being unloaded already */
sx_xunlock(&pmc_sx);
return;
}
pmc_hook = NULL; /* prevent new threads from entering module */
/* deregister event handlers */
EVENTHANDLER_DEREGISTER(process_fork, pmc_fork_tag);
EVENTHANDLER_DEREGISTER(process_exit, pmc_exit_tag);
/* send SIGBUS to all owner threads, free up allocations */
if (pmc_ownerhash)
for (ph = pmc_ownerhash;
ph <= &pmc_ownerhash[pmc_ownerhashmask];
ph++) {
LIST_FOREACH_SAFE(po, ph, po_next, tmp) {
pmc_remove_owner(po);
/* send SIGBUS to owner processes */
PMCDBG(MOD,INI,2, "cleanup signal proc=%p "
"(%d, %s)", po->po_owner,
po->po_owner->p_pid,
po->po_owner->p_comm);
PROC_LOCK(po->po_owner);
psignal(po->po_owner, SIGBUS);
PROC_UNLOCK(po->po_owner);
pmc_destroy_owner_descriptor(po);
}
}
/* reclaim allocated data structures */
if (pmc_mtxpool)
mtx_pool_destroy(&pmc_mtxpool);
mtx_destroy(&pmc_processhash_mtx);
if (pmc_processhash) {
#ifdef DEBUG
struct pmc_process *pp;
PMCDBG(MOD,INI,3, "%s", "destroy process hash");
for (prh = pmc_processhash;
prh <= &pmc_processhash[pmc_processhashmask];
prh++)
LIST_FOREACH(pp, prh, pp_next)
PMCDBG(MOD,INI,3, "pid=%d", pp->pp_proc->p_pid);
#endif
hashdestroy(pmc_processhash, M_PMC, pmc_processhashmask);
pmc_processhash = NULL;
}
if (pmc_ownerhash) {
PMCDBG(MOD,INI,3, "%s", "destroy owner hash");
hashdestroy(pmc_ownerhash, M_PMC, pmc_ownerhashmask);
pmc_ownerhash = NULL;
}
KASSERT(LIST_EMPTY(&pmc_ss_owners),
("[pmc,%d] Global SS owner list not empty", __LINE__));
KASSERT(pmc_ss_count == 0,
("[pmc,%d] Global SS count not empty", __LINE__));
/* do processor and pmc-class dependent cleanup */
maxcpu = pmc_cpu_max();
PMCDBG(MOD,INI,3, "%s", "md cleanup");
if (md) {
pmc_save_cpu_binding(&pb);
for (cpu = 0; cpu < maxcpu; cpu++) {
PMCDBG(MOD,INI,1,"pmc-cleanup cpu=%d pcs=%p",
cpu, pmc_pcpu[cpu]);
if (!pmc_cpu_is_active(cpu) || pmc_pcpu[cpu] == NULL)
continue;
pmc_select_cpu(cpu);
for (c = 0; c < md->pmd_nclass; c++)
md->pmd_classdep[c].pcd_pcpu_fini(md, cpu);
if (md->pmd_pcpu_fini)
md->pmd_pcpu_fini(md, cpu);
}
pmc_md_finalize(md);
free(md, M_PMC);
md = NULL;
pmc_restore_cpu_binding(&pb);
}
/* Free per-cpu descriptors. */
for (cpu = 0; cpu < maxcpu; cpu++) {
if (!pmc_cpu_is_active(cpu))
continue;
KASSERT(pmc_pcpu[cpu]->pc_sb != NULL,
("[pmc,%d] Null cpu sample buffer cpu=%d", __LINE__,
cpu));
free(pmc_pcpu[cpu]->pc_sb->ps_callchains, M_PMC);
free(pmc_pcpu[cpu]->pc_sb, M_PMC);
free(pmc_pcpu[cpu], M_PMC);
}
free(pmc_pcpu, M_PMC);
pmc_pcpu = NULL;
free(pmc_pcpu_saved, M_PMC);
pmc_pcpu_saved = NULL;
if (pmc_pmcdisp) {
free(pmc_pmcdisp, M_PMC);
pmc_pmcdisp = NULL;
}
if (pmc_rowindex_to_classdep) {
free(pmc_rowindex_to_classdep, M_PMC);
pmc_rowindex_to_classdep = NULL;
}
pmclog_shutdown();
sx_xunlock(&pmc_sx); /* we are done */
}
/*
* The function called at load/unload.
*/
static int
load (struct module *module __unused, int cmd, void *arg __unused)
{
int error;
error = 0;
switch (cmd) {
case MOD_LOAD :
/* initialize the subsystem */
error = pmc_initialize();
if (error != 0)
break;
PMCDBG(MOD,INI,1, "syscall=%d maxcpu=%d",
pmc_syscall_num, pmc_cpu_max());
break;
case MOD_UNLOAD :
case MOD_SHUTDOWN:
pmc_cleanup();
PMCDBG(MOD,INI,1, "%s", "unloaded");
break;
default :
error = EINVAL; /* XXX should panic(9) */
break;
}
return error;
}
/* memory pool */
MALLOC_DEFINE(M_PMC, "pmc", "Memory space for the PMC module");
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