OpenSolaris_b135/uts/intel/ia32/os/syscall.c
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2009 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#include <sys/param.h>
#include <sys/vmparam.h>
#include <sys/types.h>
#include <sys/sysmacros.h>
#include <sys/systm.h>
#include <sys/signal.h>
#include <sys/stack.h>
#include <sys/cred.h>
#include <sys/cmn_err.h>
#include <sys/user.h>
#include <sys/privregs.h>
#include <sys/psw.h>
#include <sys/debug.h>
#include <sys/errno.h>
#include <sys/proc.h>
#include <sys/modctl.h>
#include <sys/var.h>
#include <sys/inline.h>
#include <sys/syscall.h>
#include <sys/ucontext.h>
#include <sys/cpuvar.h>
#include <sys/siginfo.h>
#include <sys/trap.h>
#include <sys/vtrace.h>
#include <sys/sysinfo.h>
#include <sys/procfs.h>
#include <sys/prsystm.h>
#include <c2/audit.h>
#include <sys/modctl.h>
#include <sys/aio_impl.h>
#include <sys/tnf.h>
#include <sys/tnf_probe.h>
#include <sys/copyops.h>
#include <sys/priv.h>
#include <sys/msacct.h>
int syscalltrace = 0;
#ifdef SYSCALLTRACE
static kmutex_t systrace_lock; /* syscall tracing lock */
#else
#define syscalltrace 0
#endif /* SYSCALLTRACE */
typedef int64_t (*llfcn_t)(); /* function returning long long */
int pre_syscall(void);
void post_syscall(long rval1, long rval2);
static krwlock_t *lock_syscall(struct sysent *, uint_t);
void deferred_singlestep_trap(caddr_t);
#ifdef _SYSCALL32_IMPL
#define LWP_GETSYSENT(lwp) \
(lwp_getdatamodel(lwp) == DATAMODEL_NATIVE ? sysent : sysent32)
#else
#define LWP_GETSYSENT(lwp) (sysent)
#endif
/*
* If watchpoints are active, don't make copying in of
* system call arguments take a read watchpoint trap.
*/
static int
copyin_args(struct regs *rp, long *ap, uint_t nargs)
{
greg_t *sp = 1 + (greg_t *)rp->r_sp; /* skip ret addr */
ASSERT(nargs <= MAXSYSARGS);
return (copyin_nowatch(sp, ap, nargs * sizeof (*sp)));
}
#if defined(_SYSCALL32_IMPL)
static int
copyin_args32(struct regs *rp, long *ap, uint_t nargs)
{
greg32_t *sp = 1 + (greg32_t *)rp->r_sp; /* skip ret addr */
uint32_t a32[MAXSYSARGS];
int rc;
ASSERT(nargs <= MAXSYSARGS);
if ((rc = copyin_nowatch(sp, a32, nargs * sizeof (*sp))) == 0) {
uint32_t *a32p = &a32[0];
while (nargs--)
*ap++ = (ulong_t)*a32p++;
}
return (rc);
}
#define COPYIN_ARGS32 copyin_args32
#else
#define COPYIN_ARGS32 copyin_args
#endif
/*
* Error handler for system calls where arg copy gets fault.
*/
static longlong_t
syscall_err()
{
return (0);
}
/*
* Corresponding sysent entry to allow syscall_entry caller
* to invoke syscall_err.
*/
static struct sysent sysent_err = {
0, SE_32RVAL1, NULL, NULL, (llfcn_t)syscall_err
};
/*
* Called from syscall() when a non-trivial 32-bit system call occurs.
* Sets up the args and returns a pointer to the handler.
*/
struct sysent *
syscall_entry(kthread_t *t, long *argp)
{
klwp_t *lwp = ttolwp(t);
struct regs *rp = lwptoregs(lwp);
unsigned int code;
struct sysent *callp;
struct sysent *se = LWP_GETSYSENT(lwp);
int error = 0;
uint_t nargs;
ASSERT(t == curthread && curthread->t_schedflag & TS_DONT_SWAP);
lwp->lwp_ru.sysc++;
lwp->lwp_eosys = NORMALRETURN; /* assume this will be normal */
/*
* Set lwp_ap to point to the args, even if none are needed for this
* system call. This is for the loadable-syscall case where the
* number of args won't be known until the system call is loaded, and
* also maintains a non-NULL lwp_ap setup for get_syscall_args(). Note
* that lwp_ap MUST be set to a non-NULL value _BEFORE_ t_sysnum is
* set to non-zero; otherwise get_syscall_args(), seeing a non-zero
* t_sysnum for this thread, will charge ahead and dereference lwp_ap.
*/
lwp->lwp_ap = argp; /* for get_syscall_args */
code = rp->r_r0;
t->t_sysnum = (short)code;
callp = code >= NSYSCALL ? &nosys_ent : se + code;
if ((t->t_pre_sys | syscalltrace) != 0) {
error = pre_syscall();
/*
* pre_syscall() has taken care so that lwp_ap is current;
* it either points to syscall-entry-saved amd64 regs,
* or it points to lwp_arg[], which has been re-copied from
* the ia32 ustack, but either way, it's a current copy after
* /proc has possibly mucked with the syscall args.
*/
if (error)
return (&sysent_err); /* use dummy handler */
}
/*
* Fetch the system call arguments to the kernel stack copy used
* for syscall handling.
* Note: for loadable system calls the number of arguments required
* may not be known at this point, and will be zero if the system call
* was never loaded. Once the system call has been loaded, the number
* of args is not allowed to be changed.
*/
if ((nargs = (uint_t)callp->sy_narg) != 0 &&
COPYIN_ARGS32(rp, argp, nargs)) {
(void) set_errno(EFAULT);
return (&sysent_err); /* use dummy handler */
}
return (callp); /* return sysent entry for caller */
}
void
syscall_exit(kthread_t *t, long rval1, long rval2)
{
/*
* Handle signals and other post-call events if necessary.
*/
if ((t->t_post_sys_ast | syscalltrace) == 0) {
klwp_t *lwp = ttolwp(t);
struct regs *rp = lwptoregs(lwp);
/*
* Normal return.
* Clear error indication and set return values.
*/
rp->r_ps &= ~PS_C; /* reset carry bit */
rp->r_r0 = rval1;
rp->r_r1 = rval2;
lwp->lwp_state = LWP_USER;
} else
post_syscall(rval1, rval2);
t->t_sysnum = 0; /* invalidate args */
}
/*
* Perform pre-system-call processing, including stopping for tracing,
* auditing, etc.
*
* This routine is called only if the t_pre_sys flag is set. Any condition
* requiring pre-syscall handling must set the t_pre_sys flag. If the
* condition is persistent, this routine will repost t_pre_sys.
*/
int
pre_syscall()
{
kthread_t *t = curthread;
unsigned code = t->t_sysnum;
klwp_t *lwp = ttolwp(t);
proc_t *p = ttoproc(t);
int repost;
t->t_pre_sys = repost = 0; /* clear pre-syscall processing flag */
ASSERT(t->t_schedflag & TS_DONT_SWAP);
#if defined(DEBUG)
/*
* On the i386 kernel, lwp_ap points at the piece of the thread
* stack that we copy the users arguments into.
*
* On the amd64 kernel, the syscall arguments in the rdi..r9
* registers should be pointed at by lwp_ap. If the args need to
* be copied so that those registers can be changed without losing
* the ability to get the args for /proc, they can be saved by
* save_syscall_args(), and lwp_ap will be restored by post_syscall().
*/
if (lwp_getdatamodel(lwp) == DATAMODEL_NATIVE) {
#if defined(_LP64)
ASSERT(lwp->lwp_ap == (long *)&lwptoregs(lwp)->r_rdi);
} else {
#endif
ASSERT((caddr_t)lwp->lwp_ap > t->t_stkbase &&
(caddr_t)lwp->lwp_ap < t->t_stk);
}
#endif /* DEBUG */
/*
* Make sure the thread is holding the latest credentials for the
* process. The credentials in the process right now apply to this
* thread for the entire system call.
*/
if (t->t_cred != p->p_cred) {
cred_t *oldcred = t->t_cred;
/*
* DTrace accesses t_cred in probe context. t_cred must
* always be either NULL, or point to a valid, allocated cred
* structure.
*/
t->t_cred = crgetcred();
crfree(oldcred);
}
/*
* From the proc(4) manual page:
* When entry to a system call is being traced, the traced process
* stops after having begun the call to the system but before the
* system call arguments have been fetched from the process.
*/
if (PTOU(p)->u_systrap) {
if (prismember(&PTOU(p)->u_entrymask, code)) {
mutex_enter(&p->p_lock);
/*
* Recheck stop condition, now that lock is held.
*/
if (PTOU(p)->u_systrap &&
prismember(&PTOU(p)->u_entrymask, code)) {
stop(PR_SYSENTRY, code);
/*
* /proc may have modified syscall args,
* either in regs for amd64 or on ustack
* for ia32. Either way, arrange to
* copy them again, both for the syscall
* handler and for other consumers in
* post_syscall (like audit). Here, we
* only do amd64, and just set lwp_ap
* back to the kernel-entry stack copy;
* the syscall ml code redoes
* move-from-regs to set up for the
* syscall handler after we return. For
* ia32, save_syscall_args() below makes
* an lwp_ap-accessible copy.
*/
#if defined(_LP64)
if (lwp_getdatamodel(lwp) == DATAMODEL_NATIVE) {
lwp->lwp_argsaved = 0;
lwp->lwp_ap =
(long *)&lwptoregs(lwp)->r_rdi;
}
#endif
}
mutex_exit(&p->p_lock);
}
repost = 1;
}
/*
* ia32 kernel, or ia32 proc on amd64 kernel: keep args in
* lwp_arg for post-syscall processing, regardless of whether
* they might have been changed in /proc above.
*/
#if defined(_LP64)
if (lwp_getdatamodel(lwp) != DATAMODEL_NATIVE)
#endif
(void) save_syscall_args();
if (lwp->lwp_sysabort) {
/*
* lwp_sysabort may have been set via /proc while the process
* was stopped on PR_SYSENTRY. If so, abort the system call.
* Override any error from the copyin() of the arguments.
*/
lwp->lwp_sysabort = 0;
(void) set_errno(EINTR); /* forces post_sys */
t->t_pre_sys = 1; /* repost anyway */
return (1); /* don't do system call, return EINTR */
}
if (audit_active) { /* begin auditing for this syscall */
int error;
if (error = audit_start(T_SYSCALL, code, 0, lwp)) {
t->t_pre_sys = 1; /* repost anyway */
(void) set_errno(error);
return (1);
}
repost = 1;
}
#ifndef NPROBE
/* Kernel probe */
if (tnf_tracing_active) {
TNF_PROBE_1(syscall_start, "syscall thread", /* CSTYLED */,
tnf_sysnum, sysnum, t->t_sysnum);
t->t_post_sys = 1; /* make sure post_syscall runs */
repost = 1;
}
#endif /* NPROBE */
#ifdef SYSCALLTRACE
if (syscalltrace) {
int i;
long *ap;
char *cp;
char *sysname;
struct sysent *callp;
if (code >= NSYSCALL)
callp = &nosys_ent; /* nosys has no args */
else
callp = LWP_GETSYSENT(lwp) + code;
(void) save_syscall_args();
mutex_enter(&systrace_lock);
printf("%d: ", p->p_pid);
if (code >= NSYSCALL)
printf("0x%x", code);
else {
sysname = mod_getsysname(code);
printf("%s[0x%x/0x%p]", sysname == NULL ? "NULL" :
sysname, code, callp->sy_callc);
}
cp = "(";
for (i = 0, ap = lwp->lwp_ap; i < callp->sy_narg; i++, ap++) {
printf("%s%lx", cp, *ap);
cp = ", ";
}
if (i)
printf(")");
printf(" %s id=0x%p\n", PTOU(p)->u_comm, curthread);
mutex_exit(&systrace_lock);
}
#endif /* SYSCALLTRACE */
/*
* If there was a continuing reason for pre-syscall processing,
* set the t_pre_sys flag for the next system call.
*/
if (repost)
t->t_pre_sys = 1;
lwp->lwp_error = 0; /* for old drivers */
lwp->lwp_badpriv = PRIV_NONE;
return (0);
}
/*
* Post-syscall processing. Perform abnormal system call completion
* actions such as /proc tracing, profiling, signals, preemption, etc.
*
* This routine is called only if t_post_sys, t_sig_check, or t_astflag is set.
* Any condition requiring pre-syscall handling must set one of these.
* If the condition is persistent, this routine will repost t_post_sys.
*/
void
post_syscall(long rval1, long rval2)
{
kthread_t *t = curthread;
klwp_t *lwp = ttolwp(t);
proc_t *p = ttoproc(t);
struct regs *rp = lwptoregs(lwp);
uint_t error;
uint_t code = t->t_sysnum;
int repost = 0;
int proc_stop = 0; /* non-zero if stopping */
int sigprof = 0; /* non-zero if sending SIGPROF */
t->t_post_sys = 0;
error = lwp->lwp_errno;
/*
* Code can be zero if this is a new LWP returning after a forkall(),
* other than the one which matches the one in the parent which called
* forkall(). In these LWPs, skip most of post-syscall activity.
*/
if (code == 0)
goto sig_check;
/*
* If the trace flag is set, mark the lwp to take a single-step trap
* on return to user level (below). The x86 lcall interface and
* sysenter has already done this, and turned off the flag, but
* amd64 syscall interface has not.
*/
if (rp->r_ps & PS_T) {
lwp->lwp_pcb.pcb_flags |= DEBUG_PENDING;
rp->r_ps &= ~PS_T;
aston(curthread);
}
if (audit_active) { /* put out audit record for this syscall */
rval_t rval;
/* XX64 -- truncation of 64-bit return values? */
rval.r_val1 = (int)rval1;
rval.r_val2 = (int)rval2;
audit_finish(T_SYSCALL, code, error, &rval);
repost = 1;
}
if (curthread->t_pdmsg != NULL) {
char *m = curthread->t_pdmsg;
uprintf("%s", m);
kmem_free(m, strlen(m) + 1);
curthread->t_pdmsg = NULL;
}
/*
* If we're going to stop for /proc tracing, set the flag and
* save the arguments so that the return values don't smash them.
*/
if (PTOU(p)->u_systrap) {
if (prismember(&PTOU(p)->u_exitmask, code)) {
if (lwp_getdatamodel(lwp) == DATAMODEL_LP64)
(void) save_syscall_args();
proc_stop = 1;
}
repost = 1;
}
/*
* Similarly check to see if SIGPROF might be sent.
*/
if (curthread->t_rprof != NULL &&
curthread->t_rprof->rp_anystate != 0) {
if (lwp_getdatamodel(lwp) == DATAMODEL_LP64)
(void) save_syscall_args();
sigprof = 1;
}
if (lwp->lwp_eosys == NORMALRETURN) {
if (error == 0) {
#ifdef SYSCALLTRACE
if (syscalltrace) {
mutex_enter(&systrace_lock);
printf(
"%d: r_val1=0x%lx, r_val2=0x%lx, id 0x%p\n",
p->p_pid, rval1, rval2, curthread);
mutex_exit(&systrace_lock);
}
#endif /* SYSCALLTRACE */
rp->r_ps &= ~PS_C;
rp->r_r0 = rval1;
rp->r_r1 = rval2;
} else {
int sig;
#ifdef SYSCALLTRACE
if (syscalltrace) {
mutex_enter(&systrace_lock);
printf("%d: error=%d, id 0x%p\n",
p->p_pid, error, curthread);
mutex_exit(&systrace_lock);
}
#endif /* SYSCALLTRACE */
if (error == EINTR && t->t_activefd.a_stale)
error = EBADF;
if (error == EINTR &&
(sig = lwp->lwp_cursig) != 0 &&
sigismember(&PTOU(p)->u_sigrestart, sig) &&
PTOU(p)->u_signal[sig - 1] != SIG_DFL &&
PTOU(p)->u_signal[sig - 1] != SIG_IGN)
error = ERESTART;
rp->r_r0 = error;
rp->r_ps |= PS_C;
}
}
/*
* From the proc(4) manual page:
* When exit from a system call is being traced, the traced process
* stops on completion of the system call just prior to checking for
* signals and returning to user level. At this point all return
* values have been stored into the traced process's saved registers.
*/
if (proc_stop) {
mutex_enter(&p->p_lock);
if (PTOU(p)->u_systrap &&
prismember(&PTOU(p)->u_exitmask, code))
stop(PR_SYSEXIT, code);
mutex_exit(&p->p_lock);
}
/*
* If we are the parent returning from a successful
* vfork, wait for the child to exec or exit.
* This code must be here and not in the bowels of the system
* so that /proc can intercept exit from vfork in a timely way.
*/
if (t->t_flag & T_VFPARENT) {
ASSERT(code == SYS_vfork || code == SYS_forksys);
ASSERT(rp->r_r1 == 0 && error == 0);
vfwait((pid_t)rval1);
t->t_flag &= ~T_VFPARENT;
}
/*
* If profiling is active, bill the current PC in user-land
* and keep reposting until profiling is disabled.
*/
if (p->p_prof.pr_scale) {
if (lwp->lwp_oweupc)
profil_tick(rp->r_pc);
repost = 1;
}
sig_check:
/*
* Reset flag for next time.
* We must do this after stopping on PR_SYSEXIT
* because /proc uses the information in lwp_eosys.
*/
lwp->lwp_eosys = NORMALRETURN;
clear_stale_fd();
t->t_flag &= ~T_FORKALL;
if (t->t_astflag | t->t_sig_check) {
/*
* Turn off the AST flag before checking all the conditions that
* may have caused an AST. This flag is on whenever a signal or
* unusual condition should be handled after the next trap or
* syscall.
*/
astoff(t);
/*
* If a single-step trap occurred on a syscall (see trap())
* recognize it now. Do this before checking for signals
* because deferred_singlestep_trap() may generate a SIGTRAP to
* the LWP or may otherwise mark the LWP to call issig(FORREAL).
*/
if (lwp->lwp_pcb.pcb_flags & DEBUG_PENDING)
deferred_singlestep_trap((caddr_t)rp->r_pc);
t->t_sig_check = 0;
/*
* The following check is legal for the following reasons:
* 1) The thread we are checking, is ourselves, so there is
* no way the proc can go away.
* 2) The only time we need to be protected by the
* lock is if the binding is changed.
*
* Note we will still take the lock and check the binding
* if the condition was true without the lock held. This
* prevents lock contention among threads owned by the
* same proc.
*/
if (curthread->t_proc_flag & TP_CHANGEBIND) {
mutex_enter(&p->p_lock);
if (curthread->t_proc_flag & TP_CHANGEBIND) {
timer_lwpbind();
curthread->t_proc_flag &= ~TP_CHANGEBIND;
}
mutex_exit(&p->p_lock);
}
/*
* for kaio requests on the special kaio poll queue,
* copyout their results to user memory.
*/
if (p->p_aio)
aio_cleanup(0);
/*
* If this LWP was asked to hold, call holdlwp(), which will
* stop. holdlwps() sets this up and calls pokelwps() which
* sets the AST flag.
*
* Also check TP_EXITLWP, since this is used by fresh new LWPs
* through lwp_rtt(). That flag is set if the lwp_create(2)
* syscall failed after creating the LWP.
*/
if (ISHOLD(p) || (t->t_proc_flag & TP_EXITLWP))
holdlwp();
/*
* All code that sets signals and makes ISSIG_PENDING
* evaluate true must set t_sig_check afterwards.
*/
if (ISSIG_PENDING(t, lwp, p)) {
if (issig(FORREAL))
psig();
t->t_sig_check = 1; /* recheck next time */
}
if (sigprof) {
int nargs = (code > 0 && code < NSYSCALL)?
LWP_GETSYSENT(lwp)[code].sy_narg : 0;
realsigprof(code, nargs, error);
t->t_sig_check = 1; /* recheck next time */
}
/*
* If a performance counter overflow interrupt was
* delivered *during* the syscall, then re-enable the
* AST so that we take a trip through trap() to cause
* the SIGEMT to be delivered.
*/
if (lwp->lwp_pcb.pcb_flags & CPC_OVERFLOW)
aston(t);
/*
* /proc can't enable/disable the trace bit itself
* because that could race with the call gate used by
* system calls via "lcall". If that happened, an
* invalid EFLAGS would result. prstep()/prnostep()
* therefore schedule an AST for the purpose.
*/
if (lwp->lwp_pcb.pcb_flags & REQUEST_STEP) {
lwp->lwp_pcb.pcb_flags &= ~REQUEST_STEP;
rp->r_ps |= PS_T;
}
if (lwp->lwp_pcb.pcb_flags & REQUEST_NOSTEP) {
lwp->lwp_pcb.pcb_flags &= ~REQUEST_NOSTEP;
rp->r_ps &= ~PS_T;
}
}
lwp->lwp_errno = 0; /* clear error for next time */
#ifndef NPROBE
/* Kernel probe */
if (tnf_tracing_active) {
TNF_PROBE_3(syscall_end, "syscall thread", /* CSTYLED */,
tnf_long, rval1, rval1,
tnf_long, rval2, rval2,
tnf_long, errno, (long)error);
repost = 1;
}
#endif /* NPROBE */
/*
* Set state to LWP_USER here so preempt won't give us a kernel
* priority if it occurs after this point. Call CL_TRAPRET() to
* restore the user-level priority.
*
* It is important that no locks (other than spinlocks) be entered
* after this point before returning to user mode (unless lwp_state
* is set back to LWP_SYS).
*
* XXX Sampled times past this point are charged to the user.
*/
lwp->lwp_state = LWP_USER;
if (t->t_trapret) {
t->t_trapret = 0;
thread_lock(t);
CL_TRAPRET(t);
thread_unlock(t);
}
if (CPU->cpu_runrun || t->t_schedflag & TS_ANYWAITQ)
preempt();
prunstop();
lwp->lwp_errno = 0; /* clear error for next time */
/*
* The thread lock must be held in order to clear sysnum and reset
* lwp_ap atomically with respect to other threads in the system that
* may be looking at the args via lwp_ap from get_syscall_args().
*/
thread_lock(t);
t->t_sysnum = 0; /* no longer in a system call */
if (lwp_getdatamodel(lwp) == DATAMODEL_NATIVE) {
#if defined(_LP64)
/*
* In case the args were copied to the lwp, reset the
* pointer so the next syscall will have the right
* lwp_ap pointer.
*/
lwp->lwp_ap = (long *)&rp->r_rdi;
} else {
#endif
lwp->lwp_ap = NULL; /* reset on every syscall entry */
}
thread_unlock(t);
lwp->lwp_argsaved = 0;
/*
* If there was a continuing reason for post-syscall processing,
* set the t_post_sys flag for the next system call.
*/
if (repost)
t->t_post_sys = 1;
/*
* If there is a ustack registered for this lwp, and the stack rlimit
* has been altered, read in the ustack. If the saved stack rlimit
* matches the bounds of the ustack, update the ustack to reflect
* the new rlimit. If the new stack rlimit is RLIM_INFINITY, disable
* stack checking by setting the size to 0.
*/
if (lwp->lwp_ustack != 0 && lwp->lwp_old_stk_ctl != 0) {
rlim64_t new_size;
caddr_t top;
stack_t stk;
struct rlimit64 rl;
mutex_enter(&p->p_lock);
new_size = p->p_stk_ctl;
top = p->p_usrstack;
(void) rctl_rlimit_get(rctlproc_legacy[RLIMIT_STACK], p, &rl);
mutex_exit(&p->p_lock);
if (rl.rlim_cur == RLIM64_INFINITY)
new_size = 0;
if (copyin((stack_t *)lwp->lwp_ustack, &stk,
sizeof (stack_t)) == 0 &&
(stk.ss_size == lwp->lwp_old_stk_ctl ||
stk.ss_size == 0) &&
stk.ss_sp == top - stk.ss_size) {
stk.ss_sp = (void *)((uintptr_t)stk.ss_sp +
stk.ss_size - (uintptr_t)new_size);
stk.ss_size = new_size;
(void) copyout(&stk, (stack_t *)lwp->lwp_ustack,
sizeof (stack_t));
}
lwp->lwp_old_stk_ctl = 0;
}
}
/*
* Called from post_syscall() when a deferred singlestep is to be taken.
*/
void
deferred_singlestep_trap(caddr_t pc)
{
proc_t *p = ttoproc(curthread);
klwp_t *lwp = ttolwp(curthread);
pcb_t *pcb = &lwp->lwp_pcb;
uint_t fault = 0;
k_siginfo_t siginfo;
bzero(&siginfo, sizeof (siginfo));
/*
* If both NORMAL_STEP and WATCH_STEP are in
* effect, give precedence to WATCH_STEP.
* If neither is set, user must have set the
* PS_T bit in %efl; treat this as NORMAL_STEP.
*/
if ((fault = undo_watch_step(&siginfo)) == 0 &&
((pcb->pcb_flags & NORMAL_STEP) ||
!(pcb->pcb_flags & WATCH_STEP))) {
siginfo.si_signo = SIGTRAP;
siginfo.si_code = TRAP_TRACE;
siginfo.si_addr = pc;
fault = FLTTRACE;
}
pcb->pcb_flags &= ~(DEBUG_PENDING|NORMAL_STEP|WATCH_STEP);
if (fault) {
/*
* Remember the fault and fault adddress
* for real-time (SIGPROF) profiling.
*/
lwp->lwp_lastfault = fault;
lwp->lwp_lastfaddr = siginfo.si_addr;
/*
* If a debugger has declared this fault to be an
* event of interest, stop the lwp. Otherwise just
* deliver the associated signal.
*/
if (prismember(&p->p_fltmask, fault) &&
stop_on_fault(fault, &siginfo) == 0)
siginfo.si_signo = 0;
}
if (siginfo.si_signo)
trapsig(&siginfo, 1);
}
/*
* nonexistent system call-- signal lwp (may want to handle it)
* flag error if lwp won't see signal immediately
*/
int64_t
nosys()
{
tsignal(curthread, SIGSYS);
return (set_errno(ENOSYS));
}
/*
* Execute a 32-bit system call on behalf of the current thread.
*/
void
dosyscall(void)
{
/*
* Need space on the stack to store syscall arguments.
*/
long syscall_args[MAXSYSARGS];
struct sysent *se;
int64_t ret;
syscall_mstate(LMS_TRAP, LMS_SYSTEM);
ASSERT(curproc->p_model == DATAMODEL_ILP32);
CPU_STATS_ENTER_K();
CPU_STATS_ADDQ(CPU, sys, syscall, 1);
CPU_STATS_EXIT_K();
se = syscall_entry(curthread, syscall_args);
/*
* syscall_entry() copied all 8 arguments into syscall_args.
*/
ret = se->sy_callc(syscall_args[0], syscall_args[1], syscall_args[2],
syscall_args[3], syscall_args[4], syscall_args[5], syscall_args[6],
syscall_args[7]);
syscall_exit(curthread, (int)ret & 0xffffffffu, (int)(ret >> 32));
syscall_mstate(LMS_SYSTEM, LMS_TRAP);
}
/*
* Get the arguments to the current system call. See comment atop
* save_syscall_args() regarding lwp_ap usage.
*/
uint_t
get_syscall_args(klwp_t *lwp, long *argp, int *nargsp)
{
kthread_t *t = lwptot(lwp);
ulong_t mask = 0xfffffffful;
uint_t code;
long *ap;
int nargs;
#if defined(_LP64)
if (lwp_getdatamodel(lwp) == DATAMODEL_LP64)
mask = 0xfffffffffffffffful;
#endif
/*
* The thread lock must be held while looking at the arguments to ensure
* they don't go away via post_syscall().
* get_syscall_args() is the only routine to read them which is callable
* outside the LWP in question and hence the only one that must be
* synchronized in this manner.
*/
thread_lock(t);
code = t->t_sysnum;
ap = lwp->lwp_ap;
thread_unlock(t);
if (code != 0 && code < NSYSCALL) {
nargs = LWP_GETSYSENT(lwp)[code].sy_narg;
ASSERT(nargs <= MAXSYSARGS);
*nargsp = nargs;
while (nargs-- > 0)
*argp++ = *ap++ & mask;
} else {
*nargsp = 0;
}
return (code);
}
#ifdef _SYSCALL32_IMPL
/*
* Get the arguments to the current 32-bit system call.
*/
uint_t
get_syscall32_args(klwp_t *lwp, int *argp, int *nargsp)
{
long args[MAXSYSARGS];
uint_t i, code;
code = get_syscall_args(lwp, args, nargsp);
for (i = 0; i != *nargsp; i++)
*argp++ = (int)args[i];
return (code);
}
#endif
/*
* Save the system call arguments in a safe place.
*
* On the i386 kernel:
*
* Copy the users args prior to changing the stack or stack pointer.
* This is so /proc will be able to get a valid copy of the
* args from the user stack even after the user stack has been changed.
* Note that the kernel stack copy of the args may also have been
* changed by a system call handler which takes C-style arguments.
*
* Note that this may be called by stop() from trap(). In that case
* t_sysnum will be zero (syscall_exit clears it), so no args will be
* copied.
*
* On the amd64 kernel:
*
* For 64-bit applications, lwp->lwp_ap normally points to %rdi..%r9
* in the reg structure. If the user is going to change the argument
* registers, rax, or the stack and might want to get the args (for
* /proc tracing), it must copy the args elsewhere via save_syscall_args().
*
* For 32-bit applications, lwp->lwp_ap normally points to a copy of
* the system call arguments on the kernel stack made from the user
* stack. Copy the args prior to change the stack or stack pointer.
* This is so /proc will be able to get a valid copy of the args
* from the user stack even after that stack has been changed.
*
* This may be called from stop() even when we're not in a system call.
* Since there's no easy way to tell, this must be safe (not panic).
* If the copyins get data faults, return non-zero.
*/
int
save_syscall_args()
{
kthread_t *t = curthread;
klwp_t *lwp = ttolwp(t);
uint_t code = t->t_sysnum;
uint_t nargs;
if (lwp->lwp_argsaved || code == 0)
return (0); /* args already saved or not needed */
if (code >= NSYSCALL) {
nargs = 0; /* illegal syscall */
} else {
struct sysent *se = LWP_GETSYSENT(lwp);
struct sysent *callp = se + code;
nargs = callp->sy_narg;
if (LOADABLE_SYSCALL(callp) && nargs == 0) {
krwlock_t *module_lock;
/*
* Find out how many arguments the system
* call uses.
*
* We have the property that loaded syscalls
* never change the number of arguments they
* use after they've been loaded once. This
* allows us to stop for /proc tracing without
* holding the module lock.
* /proc is assured that sy_narg is valid.
*/
module_lock = lock_syscall(se, code);
nargs = callp->sy_narg;
rw_exit(module_lock);
}
}
/*
* Fetch the system call arguments.
*/
if (nargs == 0)
goto out;
ASSERT(nargs <= MAXSYSARGS);
if (lwp_getdatamodel(lwp) == DATAMODEL_NATIVE) {
#if defined(_LP64)
struct regs *rp = lwptoregs(lwp);
lwp->lwp_arg[0] = rp->r_rdi;
lwp->lwp_arg[1] = rp->r_rsi;
lwp->lwp_arg[2] = rp->r_rdx;
lwp->lwp_arg[3] = rp->r_rcx;
lwp->lwp_arg[4] = rp->r_r8;
lwp->lwp_arg[5] = rp->r_r9;
if (nargs > 6 && copyin_args(rp, &lwp->lwp_arg[6], nargs - 6))
return (-1);
} else {
#endif
if (COPYIN_ARGS32(lwptoregs(lwp), lwp->lwp_arg, nargs))
return (-1);
}
out:
lwp->lwp_ap = lwp->lwp_arg;
lwp->lwp_argsaved = 1;
t->t_post_sys = 1; /* so lwp_ap will be reset */
return (0);
}
void
reset_syscall_args(void)
{
ttolwp(curthread)->lwp_argsaved = 0;
}
/*
* Call a system call which takes a pointer to the user args struct and
* a pointer to the return values. This is a bit slower than the standard
* C arg-passing method in some cases.
*/
int64_t
syscall_ap(void)
{
uint_t error;
struct sysent *callp;
rval_t rval;
kthread_t *t = curthread;
klwp_t *lwp = ttolwp(t);
struct regs *rp = lwptoregs(lwp);
callp = LWP_GETSYSENT(lwp) + t->t_sysnum;
#if defined(__amd64)
/*
* If the arguments don't fit in registers %rdi-%r9, make sure they
* have been copied to the lwp_arg array.
*/
if (callp->sy_narg > 6 && save_syscall_args())
return ((int64_t)set_errno(EFAULT));
#endif
rval.r_val1 = 0;
rval.r_val2 = rp->r_r1;
lwp->lwp_error = 0; /* for old drivers */
error = (*(callp->sy_call))(lwp->lwp_ap, &rval);
if (error)
return ((longlong_t)set_errno(error));
return (rval.r_vals);
}
/*
* Load system call module.
* Returns with pointer to held read lock for module.
*/
static krwlock_t *
lock_syscall(struct sysent *table, uint_t code)
{
krwlock_t *module_lock;
struct modctl *modp;
int id;
struct sysent *callp;
callp = table + code;
module_lock = callp->sy_lock;
/*
* Optimization to only call modload if we don't have a loaded
* syscall.
*/
rw_enter(module_lock, RW_READER);
if (LOADED_SYSCALL(callp))
return (module_lock);
rw_exit(module_lock);
for (;;) {
if ((id = modload("sys", syscallnames[code])) == -1)
break;
/*
* If we loaded successfully at least once, the modctl
* will still be valid, so we try to grab it by filename.
* If this call fails, it's because the mod_filename
* was changed after the call to modload() (mod_hold_by_name()
* is the likely culprit). We can safely just take
* another lap if this is the case; the modload() will
* change the mod_filename back to one by which we can
* find the modctl.
*/
modp = mod_find_by_filename("sys", syscallnames[code]);
if (modp == NULL)
continue;
mutex_enter(&mod_lock);
if (!modp->mod_installed) {
mutex_exit(&mod_lock);
continue;
}
break;
}
rw_enter(module_lock, RW_READER);
if (id != -1)
mutex_exit(&mod_lock);
return (module_lock);
}
/*
* Loadable syscall support.
* If needed, load the module, then reserve it by holding a read
* lock for the duration of the call.
* Later, if the syscall is not unloadable, it could patch the vector.
*/
/*ARGSUSED*/
int64_t
loadable_syscall(
long a0, long a1, long a2, long a3,
long a4, long a5, long a6, long a7)
{
klwp_t *lwp = ttolwp(curthread);
int64_t rval;
struct sysent *callp;
struct sysent *se = LWP_GETSYSENT(lwp);
krwlock_t *module_lock;
int code, error = 0;
int64_t (*sy_call)();
code = curthread->t_sysnum;
callp = se + code;
/*
* Try to autoload the system call if necessary
*/
module_lock = lock_syscall(se, code);
THREAD_KPRI_RELEASE(); /* drop priority given by rw_enter */
/*
* we've locked either the loaded syscall or nosys
*/
if (lwp_getdatamodel(lwp) == DATAMODEL_NATIVE) {
#if defined(_LP64)
if (callp->sy_flags & SE_ARGC) {
sy_call = (int64_t (*)())callp->sy_call;
rval = (*sy_call)(a0, a1, a2, a3, a4, a5);
} else
rval = syscall_ap();
} else {
#endif
/*
* Now that it's loaded, make sure enough args were copied.
*/
if (COPYIN_ARGS32(lwptoregs(lwp), lwp->lwp_ap, callp->sy_narg))
error = EFAULT;
if (error) {
rval = set_errno(error);
} else if (callp->sy_flags & SE_ARGC) {
sy_call = (int64_t (*)())callp->sy_call;
rval = (*sy_call)(lwp->lwp_ap[0], lwp->lwp_ap[1],
lwp->lwp_ap[2], lwp->lwp_ap[3], lwp->lwp_ap[4],
lwp->lwp_ap[5]);
} else
rval = syscall_ap();
}
THREAD_KPRI_REQUEST(); /* regain priority from read lock */
rw_exit(module_lock);
return (rval);
}
/*
* Indirect syscall handled in libc on x86 architectures
*/
int64_t
indir()
{
return (nosys());
}
/*
* set_errno - set an error return from the current system call.
* This could be a macro.
* This returns the value it is passed, so that the caller can
* use tail-recursion-elimination and do return (set_errno(ERRNO));
*/
uint_t
set_errno(uint_t error)
{
ASSERT(error != 0); /* must not be used to clear errno */
curthread->t_post_sys = 1; /* have post_syscall do error return */
return (ttolwp(curthread)->lwp_errno = error);
}
/*
* set_proc_pre_sys - Set pre-syscall processing for entire process.
*/
void
set_proc_pre_sys(proc_t *p)
{
kthread_t *t;
kthread_t *first;
ASSERT(MUTEX_HELD(&p->p_lock));
t = first = p->p_tlist;
do {
t->t_pre_sys = 1;
} while ((t = t->t_forw) != first);
}
/*
* set_proc_post_sys - Set post-syscall processing for entire process.
*/
void
set_proc_post_sys(proc_t *p)
{
kthread_t *t;
kthread_t *first;
ASSERT(MUTEX_HELD(&p->p_lock));
t = first = p->p_tlist;
do {
t->t_post_sys = 1;
} while ((t = t->t_forw) != first);
}
/*
* set_proc_sys - Set pre- and post-syscall processing for entire process.
*/
void
set_proc_sys(proc_t *p)
{
kthread_t *t;
kthread_t *first;
ASSERT(MUTEX_HELD(&p->p_lock));
t = first = p->p_tlist;
do {
t->t_pre_sys = 1;
t->t_post_sys = 1;
} while ((t = t->t_forw) != first);
}
/*
* set_all_proc_sys - set pre- and post-syscall processing flags for all
* user processes.
*
* This is needed when auditing, tracing, or other facilities which affect
* all processes are turned on.
*/
void
set_all_proc_sys()
{
kthread_t *t;
kthread_t *first;
mutex_enter(&pidlock);
t = first = curthread;
do {
t->t_pre_sys = 1;
t->t_post_sys = 1;
} while ((t = t->t_next) != first);
mutex_exit(&pidlock);
}
/*
* set_proc_ast - Set asynchronous service trap (AST) flag for all
* threads in process.
*/
void
set_proc_ast(proc_t *p)
{
kthread_t *t;
kthread_t *first;
ASSERT(MUTEX_HELD(&p->p_lock));
t = first = p->p_tlist;
do {
aston(t);
} while ((t = t->t_forw) != first);
}