Пример #1
0
/*
 * Define the code needed before returning to user mode, for
 * trap, mem_access_fault, and syscall.
 */
static inline void
userret(struct proc *p, int pc, u_quad_t oticks)
{
	int sig;

	/* take pending signals */
	while ((sig = CURSIG(p)) != 0)
		psig(sig);
	p->p_pri = p->p_usrpri;
	if (want_ast) {
		want_ast = 0;
		if (p->p_flag & SOWEUPC) {
			p->p_flag &= ~SOWEUPC;
			ADDUPROF(p);
		}
	}
	if (want_resched) {
		/*
		 * Since we are curproc, a clock interrupt could
		 * change our priority without changing run queues
		 * (the running process is not kept on a run queue).
		 * If this happened after we setrq ourselves but
		 * before we swtch()'ed, we might not be on the queue
		 * indicated by our priority.
		 */
		(void) splstatclock();
		setrq(p);
		p->p_stats->p_ru.ru_nivcsw++;
		swtch();
		(void) spl0();
		while ((sig = CURSIG(p)) != 0)
			psig(sig);
	}

	/*
	 * If profiling, charge recent system time to the trapped pc.
	 */
	if (p->p_flag & SPROFIL)
		addupc_task(p, pc, (int)(p->p_sticks - oticks));

	curpri = p->p_pri;
}
Пример #2
0
/*
 * Arrange for the real time profiling signal to be dispatched.
 */
void
realsigprof(int sysnum, int error)
{
	proc_t *p;
	klwp_t *lwp;

	if (curthread->t_rprof->rp_anystate == 0)
		return;
	p = ttoproc(curthread);
	lwp = ttolwp(curthread);
	mutex_enter(&p->p_lock);
	if (sigismember(&p->p_ignore, SIGPROF) ||
	    signal_is_blocked(curthread, SIGPROF)) {
		mutex_exit(&p->p_lock);
		return;
	}
	lwp->lwp_siginfo.si_signo = SIGPROF;
	lwp->lwp_siginfo.si_code = PROF_SIG;
	lwp->lwp_siginfo.si_errno = error;
	hrt2ts(gethrtime(), &lwp->lwp_siginfo.si_tstamp);
	lwp->lwp_siginfo.si_syscall = sysnum;
	lwp->lwp_siginfo.si_nsysarg = (sysnum > 0 && sysnum < NSYSCALL) ?
		LWP_GETSYSENT(lwp)[sysnum].sy_narg : 0;
	lwp->lwp_siginfo.si_fault = lwp->lwp_lastfault;
	lwp->lwp_siginfo.si_faddr = lwp->lwp_lastfaddr;
	lwp->lwp_lastfault = 0;
	lwp->lwp_lastfaddr = NULL;
	sigtoproc(p, curthread, SIGPROF);
	mutex_exit(&p->p_lock);
	ASSERT(lwp->lwp_cursig == 0);
	if (issig(FORREAL)) {
		psig();
	}
	mutex_enter(&p->p_lock);
	lwp->lwp_siginfo.si_signo = 0;
	bzero(curthread->t_rprof, sizeof (*curthread->t_rprof));
	mutex_exit(&p->p_lock);
}
Пример #3
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);
	}
#ifdef C2_AUDIT
	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;
	}
#endif /* C2_AUDIT */

	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 (code == SYS_vfork && rp->r_r1 == 0 && error == 0)
		vfwait((pid_t)rval1);

	/*
	 * 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) {
			realsigprof(code, 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)
		preempt();

	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;
	}
}
Пример #4
0
/*
 * Common tasks always done by _sys_rtt, called with interrupts disabled.
 * Returns 1 if returning to userland, 0 if returning to system mode.
 */
int
sys_rtt_common(struct regs *rp)
{
	kthread_t *tp;
	extern void mutex_exit_critical_start();
	extern long mutex_exit_critical_size;
	extern void mutex_owner_running_critical_start();
	extern long mutex_owner_running_critical_size;

loop:

	/*
	 * Check if returning to user
	 */
	tp = CPU->cpu_thread;
	if (USERMODE(rp->r_cs)) {
		/*
		 * Check if AST pending.
		 */
		if (tp->t_astflag) {
			/*
			 * Let trap() handle the AST
			 */
			sti();
			rp->r_trapno = T_AST;
			trap(rp, (caddr_t)0, CPU->cpu_id);
			cli();
			goto loop;
		}

#if defined(__amd64)
		/*
		 * We are done if segment registers do not need updating.
		 */
		if (tp->t_lwp->lwp_pcb.pcb_rupdate == 0)
			return (1);

		if (update_sregs(rp, tp->t_lwp)) {
			/*
			 * 1 or more of the selectors is bad.
			 * Deliver a SIGSEGV.
			 */
			proc_t *p = ttoproc(tp);

			sti();
			mutex_enter(&p->p_lock);
			tp->t_lwp->lwp_cursig = SIGSEGV;
			mutex_exit(&p->p_lock);
			psig();
			tp->t_sig_check = 1;
			cli();
		}
		tp->t_lwp->lwp_pcb.pcb_rupdate = 0;

#endif	/* __amd64 */
		return (1);
	}

	/*
	 * Here if we are returning to supervisor mode.
	 * Check for a kernel preemption request.
	 */
	if (CPU->cpu_kprunrun && (rp->r_ps & PS_IE)) {

		/*
		 * Do nothing if already in kpreempt
		 */
		if (!tp->t_preempt_lk) {
			tp->t_preempt_lk = 1;
			sti();
			kpreempt(1); /* asynchronous kpreempt call */
			cli();
			tp->t_preempt_lk = 0;
		}
	}

	/*
	 * If we interrupted the mutex_exit() critical region we must
	 * reset the PC back to the beginning to prevent missed wakeups
	 * See the comments in mutex_exit() for details.
	 */
	if ((uintptr_t)rp->r_pc - (uintptr_t)mutex_exit_critical_start <
	    mutex_exit_critical_size) {
		rp->r_pc = (greg_t)mutex_exit_critical_start;
	}

	/*
	 * If we interrupted the mutex_owner_running() critical region we
	 * must reset the PC back to the beginning to prevent dereferencing
	 * of a freed thread pointer. See the comments in mutex_owner_running
	 * for details.
	 */
	if ((uintptr_t)rp->r_pc -
	    (uintptr_t)mutex_owner_running_critical_start <
	    mutex_owner_running_critical_size) {
		rp->r_pc = (greg_t)mutex_owner_running_critical_start;
	}

	return (0);
}