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freebsd-nq/sys/amd64/amd64/trap.c
Konstantin Belousov 1772c3e9bb Provide private per-CPU GDTs on amd64. This is required at least for the 
linux CB_GS32BIT to work.

Noted by:	nox
Reviewed by:	peter
MFC after:	1 week
2008-09-08 09:55:51 +00:00

997 lines
25 KiB
C
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/*-
* Copyright (C) 1994, David Greenman
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* the University of Utah, and William Jolitz.
*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
* from: @(#)trap.c 7.4 (Berkeley) 5/13/91
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* AMD64 Trap and System call handling
*/
#include "opt_clock.h"
#include "opt_cpu.h"
#include "opt_hwpmc_hooks.h"
#include "opt_isa.h"
#include "opt_kdb.h"
#include "opt_kdtrace.h"
#include "opt_ktrace.h"
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/pioctl.h>
#include <sys/ptrace.h>
#include <sys/kdb.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/resourcevar.h>
#include <sys/signalvar.h>
#include <sys/syscall.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>
#include <sys/uio.h>
#include <sys/vmmeter.h>
#ifdef KTRACE
#include <sys/ktrace.h>
#endif
#ifdef HWPMC_HOOKS
#include <sys/pmckern.h>
#endif
#include <security/audit/audit.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_kern.h>
#include <vm/vm_map.h>
#include <vm/vm_page.h>
#include <vm/vm_extern.h>
#include <machine/cpu.h>
#include <machine/intr_machdep.h>
#include <machine/md_var.h>
#include <machine/pcb.h>
#ifdef SMP
#include <machine/smp.h>
#endif
#include <machine/tss.h>
#ifdef KDTRACE_HOOKS
#include <sys/dtrace_bsd.h>
/*
* This is a hook which is initialised by the dtrace module
* to handle traps which might occur during DTrace probe
* execution.
*/
dtrace_trap_func_t dtrace_trap_func;
dtrace_doubletrap_func_t dtrace_doubletrap_func;
/*
* This is a hook which is initialised by the systrace module
* when it is loaded. This keeps the DTrace syscall provider
* implementation opaque.
*/
systrace_probe_func_t systrace_probe_func;
#endif
extern void trap(struct trapframe *frame);
extern void syscall(struct trapframe *frame);
void dblfault_handler(struct trapframe *frame);
static int trap_pfault(struct trapframe *, int);
static void trap_fatal(struct trapframe *, vm_offset_t);
#define MAX_TRAP_MSG 30
static char *trap_msg[] = {
"", /* 0 unused */
"privileged instruction fault", /* 1 T_PRIVINFLT */
"", /* 2 unused */
"breakpoint instruction fault", /* 3 T_BPTFLT */
"", /* 4 unused */
"", /* 5 unused */
"arithmetic trap", /* 6 T_ARITHTRAP */
"", /* 7 unused */
"", /* 8 unused */
"general protection fault", /* 9 T_PROTFLT */
"trace trap", /* 10 T_TRCTRAP */
"", /* 11 unused */
"page fault", /* 12 T_PAGEFLT */
"", /* 13 unused */
"alignment fault", /* 14 T_ALIGNFLT */
"", /* 15 unused */
"", /* 16 unused */
"", /* 17 unused */
"integer divide fault", /* 18 T_DIVIDE */
"non-maskable interrupt trap", /* 19 T_NMI */
"overflow trap", /* 20 T_OFLOW */
"FPU bounds check fault", /* 21 T_BOUND */
"FPU device not available", /* 22 T_DNA */
"double fault", /* 23 T_DOUBLEFLT */
"FPU operand fetch fault", /* 24 T_FPOPFLT */
"invalid TSS fault", /* 25 T_TSSFLT */
"segment not present fault", /* 26 T_SEGNPFLT */
"stack fault", /* 27 T_STKFLT */
"machine check trap", /* 28 T_MCHK */
"SIMD floating-point exception", /* 29 T_XMMFLT */
"reserved (unknown) fault", /* 30 T_RESERVED */
};
#ifdef KDB
static int kdb_on_nmi = 1;
SYSCTL_INT(_machdep, OID_AUTO, kdb_on_nmi, CTLFLAG_RW,
&kdb_on_nmi, 0, "Go to KDB on NMI");
#endif
static int panic_on_nmi = 1;
SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW,
&panic_on_nmi, 0, "Panic on NMI");
static int prot_fault_translation = 0;
SYSCTL_INT(_machdep, OID_AUTO, prot_fault_translation, CTLFLAG_RW,
&prot_fault_translation, 0, "Select signal to deliver on protection fault");
extern char *syscallnames[];
/*
* Exception, fault, and trap interface to the FreeBSD kernel.
* This common code is called from assembly language IDT gate entry
* routines that prepare a suitable stack frame, and restore this
* frame after the exception has been processed.
*/
void
trap(struct trapframe *frame)
{
struct thread *td = curthread;
struct proc *p = td->td_proc;
int i = 0, ucode = 0, code;
u_int type;
register_t addr = 0;
ksiginfo_t ksi;
PCPU_INC(cnt.v_trap);
type = frame->tf_trapno;
#ifdef SMP
#ifdef STOP_NMI
/* Handler for NMI IPIs used for stopping CPUs. */
if (type == T_NMI) {
if (ipi_nmi_handler() == 0)
goto out;
}
#endif /* STOP_NMI */
#endif /* SMP */
#ifdef KDB
if (kdb_active) {
kdb_reenter();
goto out;
}
#endif
#ifdef HWPMC_HOOKS
/*
* CPU PMCs interrupt using an NMI. If the PMC module is
* active, pass the 'rip' value to the PMC module's interrupt
* handler. A return value of '1' from the handler means that
* the NMI was handled by it and we can return immediately.
*/
if (type == T_NMI && pmc_intr &&
(*pmc_intr)(PCPU_GET(cpuid), frame))
goto out;
#endif
#ifdef KDTRACE_HOOKS
/*
* A trap can occur while DTrace executes a probe. Before
* executing the probe, DTrace blocks re-scheduling and sets
* a flag in it's per-cpu flags to indicate that it doesn't
* want to fault. On returning from the the probe, the no-fault
* flag is cleared and finally re-scheduling is enabled.
*
* If the DTrace kernel module has registered a trap handler,
* call it and if it returns non-zero, assume that it has
* handled the trap and modified the trap frame so that this
* function can return normally.
*/
if (dtrace_trap_func != NULL)
if ((*dtrace_trap_func)(frame, type))
goto out;
#endif
if ((frame->tf_rflags & PSL_I) == 0) {
/*
* Buggy application or kernel code has disabled
* interrupts and then trapped. Enabling interrupts
* now is wrong, but it is better than running with
* interrupts disabled until they are accidentally
* enabled later.
*/
if (ISPL(frame->tf_cs) == SEL_UPL)
printf(
"pid %ld (%s): trap %d with interrupts disabled\n",
(long)curproc->p_pid, curthread->td_name, type);
else if (type != T_NMI && type != T_BPTFLT &&
type != T_TRCTRAP) {
/*
* XXX not quite right, since this may be for a
* multiple fault in user mode.
*/
printf("kernel trap %d with interrupts disabled\n",
type);
/*
* We shouldn't enable interrupts while holding a
* spin lock or servicing an NMI.
*/
if (type != T_NMI && td->td_md.md_spinlock_count == 0)
enable_intr();
}
}
code = frame->tf_err;
if (type == T_PAGEFLT) {
/*
* If we get a page fault while in a critical section, then
* it is most likely a fatal kernel page fault. The kernel
* is already going to panic trying to get a sleep lock to
* do the VM lookup, so just consider it a fatal trap so the
* kernel can print out a useful trap message and even get
* to the debugger.
*
* If we get a page fault while holding a non-sleepable
* lock, then it is most likely a fatal kernel page fault.
* If WITNESS is enabled, then it's going to whine about
* bogus LORs with various VM locks, so just skip to the
* fatal trap handling directly.
*/
if (td->td_critnest != 0 ||
WITNESS_CHECK(WARN_SLEEPOK | WARN_GIANTOK, NULL,
"Kernel page fault") != 0)
trap_fatal(frame, frame->tf_addr);
}
if (ISPL(frame->tf_cs) == SEL_UPL) {
/* user trap */
td->td_pticks = 0;
td->td_frame = frame;
addr = frame->tf_rip;
if (td->td_ucred != p->p_ucred)
cred_update_thread(td);
switch (type) {
case T_PRIVINFLT: /* privileged instruction fault */
i = SIGILL;
ucode = ILL_PRVOPC;
break;
case T_BPTFLT: /* bpt instruction fault */
case T_TRCTRAP: /* trace trap */
enable_intr();
frame->tf_rflags &= ~PSL_T;
i = SIGTRAP;
ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT);
break;
case T_ARITHTRAP: /* arithmetic trap */
ucode = fputrap();
if (ucode == -1)
goto userout;
i = SIGFPE;
break;
case T_PROTFLT: /* general protection fault */
i = SIGBUS;
ucode = BUS_OBJERR;
break;
case T_STKFLT: /* stack fault */
case T_SEGNPFLT: /* segment not present fault */
i = SIGBUS;
ucode = BUS_ADRERR;
break;
case T_TSSFLT: /* invalid TSS fault */
i = SIGBUS;
ucode = BUS_OBJERR;
break;
case T_DOUBLEFLT: /* double fault */
default:
i = SIGBUS;
ucode = BUS_OBJERR;
break;
case T_PAGEFLT: /* page fault */
addr = frame->tf_addr;
i = trap_pfault(frame, TRUE);
if (i == -1)
goto userout;
if (i == 0)
goto user;
if (i == SIGSEGV)
ucode = SEGV_MAPERR;
else {
if (prot_fault_translation == 0) {
/*
* Autodetect.
* This check also covers the images
* without the ABI-tag ELF note.
*/
if (p->p_osrel >= 700004) {
i = SIGSEGV;
ucode = SEGV_ACCERR;
} else {
i = SIGBUS;
ucode = BUS_PAGE_FAULT;
}
} else if (prot_fault_translation == 1) {
/*
* Always compat mode.
*/
i = SIGBUS;
ucode = BUS_PAGE_FAULT;
} else {
/*
* Always SIGSEGV mode.
*/
i = SIGSEGV;
ucode = SEGV_ACCERR;
}
}
break;
case T_DIVIDE: /* integer divide fault */
ucode = FPE_INTDIV;
i = SIGFPE;
break;
#ifdef DEV_ISA
case T_NMI:
/* machine/parity/power fail/"kitchen sink" faults */
/* XXX Giant */
if (isa_nmi(code) == 0) {
#ifdef KDB
/*
* NMI can be hooked up to a pushbutton
* for debugging.
*/
if (kdb_on_nmi) {
printf ("NMI ... going to debugger\n");
kdb_trap(type, 0, frame);
}
#endif /* KDB */
goto userout;
} else if (panic_on_nmi)
panic("NMI indicates hardware failure");
break;
#endif /* DEV_ISA */
case T_OFLOW: /* integer overflow fault */
ucode = FPE_INTOVF;
i = SIGFPE;
break;
case T_BOUND: /* bounds check fault */
ucode = FPE_FLTSUB;
i = SIGFPE;
break;
case T_DNA:
/* transparent fault (due to context switch "late") */
if (fpudna())
goto userout;
printf("pid %d killed due to lack of floating point\n",
p->p_pid);
i = SIGKILL;
ucode = 0;
break;
case T_FPOPFLT: /* FPU operand fetch fault */
ucode = ILL_COPROC;
i = SIGILL;
break;
case T_XMMFLT: /* SIMD floating-point exception */
ucode = 0; /* XXX */
i = SIGFPE;
break;
}
} else {
/* kernel trap */
KASSERT(cold || td->td_ucred != NULL,
("kernel trap doesn't have ucred"));
switch (type) {
case T_PAGEFLT: /* page fault */
(void) trap_pfault(frame, FALSE);
goto out;
case T_DNA:
/*
* The kernel is apparently using fpu for copying.
* XXX this should be fatal unless the kernel has
* registered such use.
*/
if (fpudna()) {
printf("fpudna in kernel mode!\n");
goto out;
}
break;
case T_STKFLT: /* stack fault */
break;
case T_PROTFLT: /* general protection fault */
case T_SEGNPFLT: /* segment not present fault */
if (td->td_intr_nesting_level != 0)
break;
/*
* Invalid segment selectors and out of bounds
* %rip's and %rsp's can be set up in user mode.
* This causes a fault in kernel mode when the
* kernel tries to return to user mode. We want
* to get this fault so that we can fix the
* problem here and not have to check all the
* selectors and pointers when the user changes
* them.
*/
if (frame->tf_rip == (long)doreti_iret) {
frame->tf_rip = (long)doreti_iret_fault;
goto out;
}
if (PCPU_GET(curpcb)->pcb_onfault != NULL) {
frame->tf_rip =
(long)PCPU_GET(curpcb)->pcb_onfault;
goto out;
}
break;
case T_TSSFLT:
/*
* PSL_NT can be set in user mode and isn't cleared
* automatically when the kernel is entered. This
* causes a TSS fault when the kernel attempts to
* `iret' because the TSS link is uninitialized. We
* want to get this fault so that we can fix the
* problem here and not every time the kernel is
* entered.
*/
if (frame->tf_rflags & PSL_NT) {
frame->tf_rflags &= ~PSL_NT;
goto out;
}
break;
case T_TRCTRAP: /* trace trap */
/*
* Ignore debug register trace traps due to
* accesses in the user's address space, which
* can happen under several conditions such as
* if a user sets a watchpoint on a buffer and
* then passes that buffer to a system call.
* We still want to get TRCTRAPS for addresses
* in kernel space because that is useful when
* debugging the kernel.
*/
if (user_dbreg_trap()) {
/*
* Reset breakpoint bits because the
* processor doesn't
*/
/* XXX check upper bits here */
load_dr6(rdr6() & 0xfffffff0);
goto out;
}
/*
* FALLTHROUGH (TRCTRAP kernel mode, kernel address)
*/
case T_BPTFLT:
/*
* If KDB is enabled, let it handle the debugger trap.
* Otherwise, debugger traps "can't happen".
*/
#ifdef KDB
if (kdb_trap(type, 0, frame))
goto out;
#endif
break;
#ifdef DEV_ISA
case T_NMI:
/* XXX Giant */
/* machine/parity/power fail/"kitchen sink" faults */
if (isa_nmi(code) == 0) {
#ifdef KDB
/*
* NMI can be hooked up to a pushbutton
* for debugging.
*/
if (kdb_on_nmi) {
printf ("NMI ... going to debugger\n");
kdb_trap(type, 0, frame);
}
#endif /* KDB */
goto out;
} else if (panic_on_nmi == 0)
goto out;
/* FALLTHROUGH */
#endif /* DEV_ISA */
}
trap_fatal(frame, 0);
goto out;
}
/* Translate fault for emulators (e.g. Linux) */
if (*p->p_sysent->sv_transtrap)
i = (*p->p_sysent->sv_transtrap)(i, type);
ksiginfo_init_trap(&ksi);
ksi.ksi_signo = i;
ksi.ksi_code = ucode;
ksi.ksi_trapno = type;
ksi.ksi_addr = (void *)addr;
trapsignal(td, &ksi);
#ifdef DEBUG
if (type <= MAX_TRAP_MSG) {
uprintf("fatal process exception: %s",
trap_msg[type]);
if ((type == T_PAGEFLT) || (type == T_PROTFLT))
uprintf(", fault VA = 0x%lx", frame->tf_addr);
uprintf("\n");
}
#endif
user:
userret(td, frame);
mtx_assert(&Giant, MA_NOTOWNED);
userout:
out:
return;
}
static int
trap_pfault(frame, usermode)
struct trapframe *frame;
int usermode;
{
vm_offset_t va;
struct vmspace *vm = NULL;
vm_map_t map;
int rv = 0;
vm_prot_t ftype;
struct thread *td = curthread;
struct proc *p = td->td_proc;
vm_offset_t eva = frame->tf_addr;
va = trunc_page(eva);
if (va >= VM_MIN_KERNEL_ADDRESS) {
/*
* Don't allow user-mode faults in kernel address space.
*/
if (usermode)
goto nogo;
map = kernel_map;
} else {
/*
* This is a fault on non-kernel virtual memory.
* vm is initialized above to NULL. If curproc is NULL
* or curproc->p_vmspace is NULL the fault is fatal.
*/
if (p != NULL)
vm = p->p_vmspace;
if (vm == NULL)
goto nogo;
map = &vm->vm_map;
}
/*
* PGEX_I is defined only if the execute disable bit capability is
* supported and enabled.
*/
if (frame->tf_err & PGEX_W)
ftype = VM_PROT_WRITE;
else if ((frame->tf_err & PGEX_I) && pg_nx != 0)
ftype = VM_PROT_EXECUTE;
else
ftype = VM_PROT_READ;
if (map != kernel_map) {
/*
* Keep swapout from messing with us during this
* critical time.
*/
PROC_LOCK(p);
++p->p_lock;
PROC_UNLOCK(p);
/* Fault in the user page: */
rv = vm_fault(map, va, ftype,
(ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY
: VM_FAULT_NORMAL);
PROC_LOCK(p);
--p->p_lock;
PROC_UNLOCK(p);
} else {
/*
* Don't have to worry about process locking or stacks in the
* kernel.
*/
rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
}
if (rv == KERN_SUCCESS)
return (0);
nogo:
if (!usermode) {
if (td->td_intr_nesting_level == 0 &&
PCPU_GET(curpcb)->pcb_onfault != NULL) {
frame->tf_rip = (long)PCPU_GET(curpcb)->pcb_onfault;
return (0);
}
trap_fatal(frame, eva);
return (-1);
}
return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV);
}
static void
trap_fatal(frame, eva)
struct trapframe *frame;
vm_offset_t eva;
{
int code, ss;
u_int type;
long esp;
struct soft_segment_descriptor softseg;
char *msg;
code = frame->tf_err;
type = frame->tf_trapno;
sdtossd(&gdt[NGDT * PCPU_GET(cpuid) + IDXSEL(frame->tf_cs & 0xffff)],
&softseg);
if (type <= MAX_TRAP_MSG)
msg = trap_msg[type];
else
msg = "UNKNOWN";
printf("\n\nFatal trap %d: %s while in %s mode\n", type, msg,
ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel");
#ifdef SMP
/* two separate prints in case of a trap on an unmapped page */
printf("cpuid = %d; ", PCPU_GET(cpuid));
printf("apic id = %02x\n", PCPU_GET(apic_id));
#endif
if (type == T_PAGEFLT) {
printf("fault virtual address = 0x%lx\n", eva);
printf("fault code = %s %s %s, %s\n",
code & PGEX_U ? "user" : "supervisor",
code & PGEX_W ? "write" : "read",
code & PGEX_I ? "instruction" : "data",
code & PGEX_P ? "protection violation" : "page not present");
}
printf("instruction pointer = 0x%lx:0x%lx\n",
frame->tf_cs & 0xffff, frame->tf_rip);
if (ISPL(frame->tf_cs) == SEL_UPL) {
ss = frame->tf_ss & 0xffff;
esp = frame->tf_rsp;
} else {
ss = GSEL(GDATA_SEL, SEL_KPL);
esp = (long)&frame->tf_rsp;
}
printf("stack pointer = 0x%x:0x%lx\n", ss, esp);
printf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp);
printf("code segment = base 0x%lx, limit 0x%lx, type 0x%x\n",
softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type);
printf(" = DPL %d, pres %d, long %d, def32 %d, gran %d\n",
softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_long, softseg.ssd_def32,
softseg.ssd_gran);
printf("processor eflags = ");
if (frame->tf_rflags & PSL_T)
printf("trace trap, ");
if (frame->tf_rflags & PSL_I)
printf("interrupt enabled, ");
if (frame->tf_rflags & PSL_NT)
printf("nested task, ");
if (frame->tf_rflags & PSL_RF)
printf("resume, ");
printf("IOPL = %ld\n", (frame->tf_rflags & PSL_IOPL) >> 12);
printf("current process = ");
if (curproc) {
printf("%lu (%s)\n",
(u_long)curproc->p_pid, curthread->td_name ?
curthread->td_name : "");
} else {
printf("Idle\n");
}
#ifdef KDB
if (debugger_on_panic || kdb_active)
if (kdb_trap(type, 0, frame))
return;
#endif
printf("trap number = %d\n", type);
if (type <= MAX_TRAP_MSG)
panic("%s", trap_msg[type]);
else
panic("unknown/reserved trap");
}
/*
* Double fault handler. Called when a fault occurs while writing
* a frame for a trap/exception onto the stack. This usually occurs
* when the stack overflows (such is the case with infinite recursion,
* for example).
*/
void
dblfault_handler(struct trapframe *frame)
{
#ifdef KDTRACE_HOOKS
if (dtrace_doubletrap_func != NULL)
(*dtrace_doubletrap_func)();
#endif
printf("\nFatal double fault\n");
printf("rip = 0x%lx\n", frame->tf_rip);
printf("rsp = 0x%lx\n", frame->tf_rsp);
printf("rbp = 0x%lx\n", frame->tf_rbp);
#ifdef SMP
/* two separate prints in case of a trap on an unmapped page */
printf("cpuid = %d; ", PCPU_GET(cpuid));
printf("apic id = %02x\n", PCPU_GET(apic_id));
#endif
panic("double fault");
}
/*
* syscall - system call request C handler
*
* A system call is essentially treated as a trap.
*/
void
syscall(struct trapframe *frame)
{
caddr_t params;
struct sysent *callp;
struct thread *td = curthread;
struct proc *p = td->td_proc;
register_t orig_tf_rflags;
int error;
int narg;
register_t args[8];
register_t *argp;
u_int code;
int reg, regcnt;
ksiginfo_t ksi;
PCPU_INC(cnt.v_syscall);
#ifdef DIAGNOSTIC
if (ISPL(frame->tf_cs) != SEL_UPL) {
panic("syscall");
/* NOT REACHED */
}
#endif
reg = 0;
regcnt = 6;
td->td_pticks = 0;
td->td_frame = frame;
if (td->td_ucred != p->p_ucred)
cred_update_thread(td);
params = (caddr_t)frame->tf_rsp + sizeof(register_t);
code = frame->tf_rax;
orig_tf_rflags = frame->tf_rflags;
if (p->p_sysent->sv_prepsyscall) {
/*
* The prep code is MP aware.
*/
(*p->p_sysent->sv_prepsyscall)(frame, (int *)args, &code, &params);
} else {
if (code == SYS_syscall || code == SYS___syscall) {
code = frame->tf_rdi;
reg++;
regcnt--;
}
}
if (p->p_sysent->sv_mask)
code &= p->p_sysent->sv_mask;
if (code >= p->p_sysent->sv_size)
callp = &p->p_sysent->sv_table[0];
else
callp = &p->p_sysent->sv_table[code];
narg = callp->sy_narg;
/*
* copyin and the ktrsyscall()/ktrsysret() code is MP-aware
*/
KASSERT(narg <= sizeof(args) / sizeof(args[0]),
("Too many syscall arguments!"));
error = 0;
argp = &frame->tf_rdi;
argp += reg;
bcopy(argp, args, sizeof(args[0]) * regcnt);
if (narg > regcnt) {
KASSERT(params != NULL, ("copyin args with no params!"));
error = copyin(params, &args[regcnt],
(narg - regcnt) * sizeof(args[0]));
}
argp = &args[0];
#ifdef KTRACE
if (KTRPOINT(td, KTR_SYSCALL))
ktrsyscall(code, narg, argp);
#endif
CTR4(KTR_SYSC, "syscall enter thread %p pid %d proc %s code %d", td,
td->td_proc->p_pid, td->td_name, code);
td->td_syscalls++;
if (error == 0) {
td->td_retval[0] = 0;
td->td_retval[1] = frame->tf_rdx;
STOPEVENT(p, S_SCE, narg);
PTRACESTOP_SC(p, td, S_PT_SCE);
#ifdef KDTRACE_HOOKS
/*
* If the systrace module has registered it's probe
* callback and if there is a probe active for the
* syscall 'entry', process the probe.
*/
if (systrace_probe_func != NULL && callp->sy_entry != 0)
(*systrace_probe_func)(callp->sy_entry, code, callp,
args);
#endif
AUDIT_SYSCALL_ENTER(code, td);
error = (*callp->sy_call)(td, argp);
AUDIT_SYSCALL_EXIT(error, td);
/* Save the latest error return value. */
td->td_errno = error;
#ifdef KDTRACE_HOOKS
/*
* If the systrace module has registered it's probe
* callback and if there is a probe active for the
* syscall 'return', process the probe.
*/
if (systrace_probe_func != NULL && callp->sy_return != 0)
(*systrace_probe_func)(callp->sy_return, code, callp,
args);
#endif
}
switch (error) {
case 0:
frame->tf_rax = td->td_retval[0];
frame->tf_rdx = td->td_retval[1];
frame->tf_rflags &= ~PSL_C;
break;
case ERESTART:
/*
* Reconstruct pc, we know that 'syscall' is 2 bytes.
* We have to do a full context restore so that %r10
* (which was holding the value of %rcx) is restored for
* the next iteration.
*/
frame->tf_rip -= frame->tf_err;
frame->tf_r10 = frame->tf_rcx;
td->td_pcb->pcb_flags |= PCB_FULLCTX;
break;
case EJUSTRETURN:
break;
default:
if (p->p_sysent->sv_errsize) {
if (error >= p->p_sysent->sv_errsize)
error = -1; /* XXX */
else
error = p->p_sysent->sv_errtbl[error];
}
frame->tf_rax = error;
frame->tf_rflags |= PSL_C;
break;
}
/*
* Traced syscall.
*/
if (orig_tf_rflags & PSL_T) {
frame->tf_rflags &= ~PSL_T;
ksiginfo_init_trap(&ksi);
ksi.ksi_signo = SIGTRAP;
ksi.ksi_code = TRAP_TRACE;
ksi.ksi_addr = (void *)frame->tf_rip;
trapsignal(td, &ksi);
}
/*
* Check for misbehavior.
*/
WITNESS_WARN(WARN_PANIC, NULL, "System call %s returning",
(code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???");
KASSERT(td->td_critnest == 0,
("System call %s returning in a critical section",
(code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???"));
KASSERT(td->td_locks == 0,
("System call %s returning with %d locks held",
(code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???",
td->td_locks));
/*
* Handle reschedule and other end-of-syscall issues
*/
userret(td, frame);
CTR4(KTR_SYSC, "syscall exit thread %p pid %d proc %s code %d", td,
td->td_proc->p_pid, td->td_name, code);
#ifdef KTRACE
if (KTRPOINT(td, KTR_SYSRET))
ktrsysret(code, error, td->td_retval[0]);
#endif
/*
* This works because errno is findable through the
* register set. If we ever support an emulation where this
* is not the case, this code will need to be revisited.
*/
STOPEVENT(p, S_SCX, code);
PTRACESTOP_SC(p, td, S_PT_SCX);
}
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