freebsd-nq/sys/kern/subr_pcpu.c
Nathan Whitehorn 51de47e3f8 Remove assertion that a CPU be present before returning a PCPU for it. It
is up to the caller to check for a NULL return value. The assert was meant
to catch buggy code that did not check the return value. Some code, however,
was smart and used the return value to see if a CPU existed, which this
broke.

Requested by:	jhb@
2017-11-28 05:39:48 +00:00

422 lines
9.9 KiB
C

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 2001 Wind River Systems, Inc.
* All rights reserved.
* Written by: John Baldwin <jhb@FreeBSD.org>
*
* Copyright (c) 2009 Jeffrey Roberson <jeff@freebsd.org>
* All rights reserved.
*
* 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.
* 3. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* 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.
*/
/*
* This module provides MI support for per-cpu data.
*
* Each architecture determines the mapping of logical CPU IDs to physical
* CPUs. The requirements of this mapping are as follows:
* - Logical CPU IDs must reside in the range 0 ... MAXCPU - 1.
* - The mapping is not required to be dense. That is, there may be
* gaps in the mappings.
* - The platform sets the value of MAXCPU in <machine/param.h>.
* - It is suggested, but not required, that in the non-SMP case, the
* platform define MAXCPU to be 1 and define the logical ID of the
* sole CPU as 0.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_ddb.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/pcpu.h>
#include <sys/proc.h>
#include <sys/smp.h>
#include <sys/sx.h>
#include <vm/uma.h>
#include <ddb/ddb.h>
static MALLOC_DEFINE(M_PCPU, "Per-cpu", "Per-cpu resource accouting.");
struct dpcpu_free {
uintptr_t df_start;
int df_len;
TAILQ_ENTRY(dpcpu_free) df_link;
};
static DPCPU_DEFINE(char, modspace[DPCPU_MODMIN]);
static TAILQ_HEAD(, dpcpu_free) dpcpu_head = TAILQ_HEAD_INITIALIZER(dpcpu_head);
static struct sx dpcpu_lock;
uintptr_t dpcpu_off[MAXCPU];
struct pcpu *cpuid_to_pcpu[MAXCPU];
struct cpuhead cpuhead = STAILQ_HEAD_INITIALIZER(cpuhead);
/*
* Initialize the MI portions of a struct pcpu.
*/
void
pcpu_init(struct pcpu *pcpu, int cpuid, size_t size)
{
bzero(pcpu, size);
KASSERT(cpuid >= 0 && cpuid < MAXCPU,
("pcpu_init: invalid cpuid %d", cpuid));
pcpu->pc_cpuid = cpuid;
cpuid_to_pcpu[cpuid] = pcpu;
STAILQ_INSERT_TAIL(&cpuhead, pcpu, pc_allcpu);
cpu_pcpu_init(pcpu, cpuid, size);
pcpu->pc_rm_queue.rmq_next = &pcpu->pc_rm_queue;
pcpu->pc_rm_queue.rmq_prev = &pcpu->pc_rm_queue;
}
void
dpcpu_init(void *dpcpu, int cpuid)
{
struct pcpu *pcpu;
pcpu = pcpu_find(cpuid);
pcpu->pc_dynamic = (uintptr_t)dpcpu - DPCPU_START;
/*
* Initialize defaults from our linker section.
*/
memcpy(dpcpu, (void *)DPCPU_START, DPCPU_BYTES);
/*
* Place it in the global pcpu offset array.
*/
dpcpu_off[cpuid] = pcpu->pc_dynamic;
}
static void
dpcpu_startup(void *dummy __unused)
{
struct dpcpu_free *df;
df = malloc(sizeof(*df), M_PCPU, M_WAITOK | M_ZERO);
df->df_start = (uintptr_t)&DPCPU_NAME(modspace);
df->df_len = DPCPU_MODMIN;
TAILQ_INSERT_HEAD(&dpcpu_head, df, df_link);
sx_init(&dpcpu_lock, "dpcpu alloc lock");
}
SYSINIT(dpcpu, SI_SUB_KLD, SI_ORDER_FIRST, dpcpu_startup, 0);
/*
* UMA_PCPU_ZONE zones, that are available for all kernel
* consumers. Right now 64 bit zone is used for counter(9)
* and pointer zone is used by flowtable.
*/
uma_zone_t pcpu_zone_64;
uma_zone_t pcpu_zone_ptr;
static void
pcpu_zones_startup(void)
{
pcpu_zone_64 = uma_zcreate("64 pcpu", sizeof(uint64_t),
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_PCPU);
if (sizeof(uint64_t) == sizeof(void *))
pcpu_zone_ptr = pcpu_zone_64;
else
pcpu_zone_ptr = uma_zcreate("ptr pcpu", sizeof(void *),
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_PCPU);
}
SYSINIT(pcpu_zones, SI_SUB_KMEM, SI_ORDER_ANY, pcpu_zones_startup, NULL);
/*
* First-fit extent based allocator for allocating space in the per-cpu
* region reserved for modules. This is only intended for use by the
* kernel linkers to place module linker sets.
*/
void *
dpcpu_alloc(int size)
{
struct dpcpu_free *df;
void *s;
s = NULL;
size = roundup2(size, sizeof(void *));
sx_xlock(&dpcpu_lock);
TAILQ_FOREACH(df, &dpcpu_head, df_link) {
if (df->df_len < size)
continue;
if (df->df_len == size) {
s = (void *)df->df_start;
TAILQ_REMOVE(&dpcpu_head, df, df_link);
free(df, M_PCPU);
break;
}
s = (void *)df->df_start;
df->df_len -= size;
df->df_start = df->df_start + size;
break;
}
sx_xunlock(&dpcpu_lock);
return (s);
}
/*
* Free dynamic per-cpu space at module unload time.
*/
void
dpcpu_free(void *s, int size)
{
struct dpcpu_free *df;
struct dpcpu_free *dn;
uintptr_t start;
uintptr_t end;
size = roundup2(size, sizeof(void *));
start = (uintptr_t)s;
end = start + size;
/*
* Free a region of space and merge it with as many neighbors as
* possible. Keeping the list sorted simplifies this operation.
*/
sx_xlock(&dpcpu_lock);
TAILQ_FOREACH(df, &dpcpu_head, df_link) {
if (df->df_start > end)
break;
/*
* If we expand at the end of an entry we may have to
* merge it with the one following it as well.
*/
if (df->df_start + df->df_len == start) {
df->df_len += size;
dn = TAILQ_NEXT(df, df_link);
if (df->df_start + df->df_len == dn->df_start) {
df->df_len += dn->df_len;
TAILQ_REMOVE(&dpcpu_head, dn, df_link);
free(dn, M_PCPU);
}
sx_xunlock(&dpcpu_lock);
return;
}
if (df->df_start == end) {
df->df_start = start;
df->df_len += size;
sx_xunlock(&dpcpu_lock);
return;
}
}
dn = malloc(sizeof(*df), M_PCPU, M_WAITOK | M_ZERO);
dn->df_start = start;
dn->df_len = size;
if (df)
TAILQ_INSERT_BEFORE(df, dn, df_link);
else
TAILQ_INSERT_TAIL(&dpcpu_head, dn, df_link);
sx_xunlock(&dpcpu_lock);
}
/*
* Initialize the per-cpu storage from an updated linker-set region.
*/
void
dpcpu_copy(void *s, int size)
{
#ifdef SMP
uintptr_t dpcpu;
int i;
CPU_FOREACH(i) {
dpcpu = dpcpu_off[i];
if (dpcpu == 0)
continue;
memcpy((void *)(dpcpu + (uintptr_t)s), s, size);
}
#else
memcpy((void *)(dpcpu_off[0] + (uintptr_t)s), s, size);
#endif
}
/*
* Destroy a struct pcpu.
*/
void
pcpu_destroy(struct pcpu *pcpu)
{
STAILQ_REMOVE(&cpuhead, pcpu, pcpu, pc_allcpu);
cpuid_to_pcpu[pcpu->pc_cpuid] = NULL;
dpcpu_off[pcpu->pc_cpuid] = 0;
}
/*
* Locate a struct pcpu by cpu id.
*/
struct pcpu *
pcpu_find(u_int cpuid)
{
return (cpuid_to_pcpu[cpuid]);
}
int
sysctl_dpcpu_quad(SYSCTL_HANDLER_ARGS)
{
uintptr_t dpcpu;
int64_t count;
int i;
count = 0;
CPU_FOREACH(i) {
dpcpu = dpcpu_off[i];
if (dpcpu == 0)
continue;
count += *(int64_t *)(dpcpu + (uintptr_t)arg1);
}
return (SYSCTL_OUT(req, &count, sizeof(count)));
}
int
sysctl_dpcpu_long(SYSCTL_HANDLER_ARGS)
{
uintptr_t dpcpu;
long count;
int i;
count = 0;
CPU_FOREACH(i) {
dpcpu = dpcpu_off[i];
if (dpcpu == 0)
continue;
count += *(long *)(dpcpu + (uintptr_t)arg1);
}
return (SYSCTL_OUT(req, &count, sizeof(count)));
}
int
sysctl_dpcpu_int(SYSCTL_HANDLER_ARGS)
{
uintptr_t dpcpu;
int count;
int i;
count = 0;
CPU_FOREACH(i) {
dpcpu = dpcpu_off[i];
if (dpcpu == 0)
continue;
count += *(int *)(dpcpu + (uintptr_t)arg1);
}
return (SYSCTL_OUT(req, &count, sizeof(count)));
}
#ifdef DDB
DB_SHOW_COMMAND(dpcpu_off, db_show_dpcpu_off)
{
int id;
CPU_FOREACH(id) {
db_printf("dpcpu_off[%2d] = 0x%jx (+ DPCPU_START = %p)\n",
id, (uintmax_t)dpcpu_off[id],
(void *)(uintptr_t)(dpcpu_off[id] + DPCPU_START));
}
}
static void
show_pcpu(struct pcpu *pc)
{
struct thread *td;
db_printf("cpuid = %d\n", pc->pc_cpuid);
db_printf("dynamic pcpu = %p\n", (void *)pc->pc_dynamic);
db_printf("curthread = ");
td = pc->pc_curthread;
if (td != NULL)
db_printf("%p: pid %d tid %d \"%s\"\n", td, td->td_proc->p_pid,
td->td_tid, td->td_name);
else
db_printf("none\n");
db_printf("curpcb = %p\n", pc->pc_curpcb);
db_printf("fpcurthread = ");
td = pc->pc_fpcurthread;
if (td != NULL)
db_printf("%p: pid %d \"%s\"\n", td, td->td_proc->p_pid,
td->td_name);
else
db_printf("none\n");
db_printf("idlethread = ");
td = pc->pc_idlethread;
if (td != NULL)
db_printf("%p: tid %d \"%s\"\n", td, td->td_tid, td->td_name);
else
db_printf("none\n");
db_show_mdpcpu(pc);
#ifdef VIMAGE
db_printf("curvnet = %p\n", pc->pc_curthread->td_vnet);
#endif
#ifdef WITNESS
db_printf("spin locks held:\n");
witness_list_locks(&pc->pc_spinlocks, db_printf);
#endif
}
DB_SHOW_COMMAND(pcpu, db_show_pcpu)
{
struct pcpu *pc;
int id;
if (have_addr)
id = ((addr >> 4) % 16) * 10 + (addr % 16);
else
id = PCPU_GET(cpuid);
pc = pcpu_find(id);
if (pc == NULL) {
db_printf("CPU %d not found\n", id);
return;
}
show_pcpu(pc);
}
DB_SHOW_ALL_COMMAND(pcpu, db_show_cpu_all)
{
struct pcpu *pc;
int id;
db_printf("Current CPU: %d\n\n", PCPU_GET(cpuid));
CPU_FOREACH(id) {
pc = pcpu_find(id);
if (pc != NULL) {
show_pcpu(pc);
db_printf("\n");
}
}
}
DB_SHOW_ALIAS(allpcpu, db_show_cpu_all);
#endif