* 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
* 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes
* 2000-2002 x86-64 support by Andi Kleen
- *
- * $Id: signal.c,v 1.18 2001/10/17 22:30:37 ak Exp $
*/
#include <linux/sched.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/wait.h>
-#include <linux/ptrace.h>
+#include <linux/tracehook.h>
#include <linux/unistd.h>
#include <linux/stddef.h>
#include <linux/personality.h>
#include <linux/compiler.h>
-#include <linux/suspend.h>
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#include <asm/i387.h>
#include <asm/proto.h>
+#include <asm/ia32_unistd.h>
/* #define DEBUG_SIG 1 */
#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
-void ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
+int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
sigset_t *set, struct pt_regs * regs);
-void ia32_setup_frame(int sig, struct k_sigaction *ka,
+int ia32_setup_frame(int sig, struct k_sigaction *ka,
sigset_t *set, struct pt_regs * regs);
asmlinkage long
-sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize, struct pt_regs regs)
+sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
+ struct pt_regs *regs)
{
- sigset_t saveset, newset;
-
- /* XXX: Don't preclude handling different sized sigset_t's. */
- if (sigsetsize != sizeof(sigset_t))
- return -EINVAL;
-
- if (copy_from_user(&newset, unewset, sizeof(newset)))
- return -EFAULT;
- sigdelsetmask(&newset, ~_BLOCKABLE);
-
- spin_lock_irq(¤t->sighand->siglock);
- saveset = current->blocked;
- current->blocked = newset;
- recalc_sigpending();
- spin_unlock_irq(¤t->sighand->siglock);
-#if DEBUG_SIG
- printk("rt_sigsuspend savset(%lx) newset(%lx) regs(%p) rip(%lx)\n",
- saveset, newset, ®s, regs.rip);
-#endif
- regs.rax = -EINTR;
- while (1) {
- current->state = TASK_INTERRUPTIBLE;
- schedule();
- if (do_signal(®s, &saveset))
- return -EINTR;
- }
-}
-
-asmlinkage long
-sys_sigaltstack(const stack_t *uss, stack_t *uoss, struct pt_regs regs)
-{
- return do_sigaltstack(uss, uoss, regs.rsp);
+ return do_sigaltstack(uss, uoss, regs->rsp);
}
struct rt_sigframe
{
- char *pretcode;
+ char __user *pretcode;
struct ucontext uc;
struct siginfo info;
};
static int
-restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc, unsigned long *prax)
+restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, unsigned long *prax)
{
unsigned int err = 0;
COPY(r14);
COPY(r15);
+ /* Kernel saves and restores only the CS segment register on signals,
+ * which is the bare minimum needed to allow mixed 32/64-bit code.
+ * App's signal handler can save/restore other segments if needed. */
+ {
+ unsigned cs;
+ err |= __get_user(cs, &sc->cs);
+ regs->cs = cs | 3; /* Force into user mode */
+ }
+
{
unsigned int tmpflags;
err |= __get_user(tmpflags, &sc->eflags);
}
{
- struct _fpstate * buf;
+ struct _fpstate __user * buf;
err |= __get_user(buf, &sc->fpstate);
if (buf) {
- if (verify_area(VERIFY_READ, buf, sizeof(*buf)))
+ if (!access_ok(VERIFY_READ, buf, sizeof(*buf)))
goto badframe;
err |= restore_i387(buf);
+ } else {
+ struct task_struct *me = current;
+ if (used_math()) {
+ clear_fpu(me);
+ clear_used_math();
+ }
}
}
return 1;
}
-asmlinkage long sys_rt_sigreturn(struct pt_regs regs)
+asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
{
- struct rt_sigframe *frame = (struct rt_sigframe *)(regs.rsp - 8);
+ struct rt_sigframe __user *frame;
sigset_t set;
- stack_t st;
- long eax;
+ unsigned long eax;
- if (verify_area(VERIFY_READ, frame, sizeof(*frame))) {
+ frame = (struct rt_sigframe __user *)(regs->rsp - 8);
+ if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) {
goto badframe;
}
if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) {
recalc_sigpending();
spin_unlock_irq(¤t->sighand->siglock);
- if (restore_sigcontext(®s, &frame->uc.uc_mcontext, &eax)) {
+ if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &eax))
goto badframe;
- }
-#if DEBUG_SIG
+#ifdef DEBUG_SIG
printk("%d sigreturn rip:%lx rsp:%lx frame:%p rax:%lx\n",current->pid,regs.rip,regs.rsp,frame,eax);
#endif
- if (__copy_from_user(&st, &frame->uc.uc_stack, sizeof(st))) {
+ if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->rsp) == -EFAULT)
goto badframe;
- }
- /* It is more difficult to avoid calling this function than to
- call it and ignore errors. */
- do_sigaltstack(&st, NULL, regs.rsp);
return eax;
badframe:
- signal_fault(®s,frame,"sigreturn");
+ signal_fault(regs,frame,"sigreturn");
return 0;
}
*/
static inline int
-setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs, unsigned long mask, struct task_struct *me)
+setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, unsigned long mask, struct task_struct *me)
{
int err = 0;
+ err |= __put_user(regs->cs, &sc->cs);
err |= __put_user(0, &sc->gs);
err |= __put_user(0, &sc->fs);
* Determine which stack to use..
*/
-static void *
+static void __user *
get_stack(struct k_sigaction *ka, struct pt_regs *regs, unsigned long size)
{
unsigned long rsp;
rsp = regs->rsp - 128;
/* This is the X/Open sanctioned signal stack switching. */
- /* RED-PEN: redzone on that stack? */
if (ka->sa.sa_flags & SA_ONSTACK) {
if (sas_ss_flags(rsp) == 0)
rsp = current->sas_ss_sp + current->sas_ss_size;
}
- return (void *)round_down(rsp - size, 16);
+ return (void __user *)round_down(rsp - size, 16);
}
-static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
+static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
sigset_t *set, struct pt_regs * regs)
{
- struct rt_sigframe *frame;
- struct _fpstate *fp = NULL;
+ struct rt_sigframe __user *frame;
+ struct _fpstate __user *fp = NULL;
int err = 0;
struct task_struct *me = current;
- if (me->used_math) {
+ if (used_math()) {
fp = get_stack(ka, regs, sizeof(struct _fpstate));
- frame = (void *)round_down((u64)fp - sizeof(struct rt_sigframe), 16) - 8;
+ frame = (void __user *)round_down(
+ (unsigned long)fp - sizeof(struct rt_sigframe), 16) - 8;
- if (!access_ok(VERIFY_WRITE, fp, sizeof(struct _fpstate))) {
- goto give_sigsegv;
- }
+ if (!access_ok(VERIFY_WRITE, fp, sizeof(struct _fpstate)))
+ goto give_sigsegv;
if (save_i387(fp) < 0)
err |= -1;
- } else {
+ } else
frame = get_stack(ka, regs, sizeof(struct rt_sigframe)) - 8;
- }
- if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) {
+ if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
goto give_sigsegv;
- }
if (ka->sa.sa_flags & SA_SIGINFO) {
err |= copy_siginfo_to_user(&frame->info, info);
- if (err) {
+ if (err)
goto give_sigsegv;
}
- }
/* Create the ucontext. */
err |= __put_user(0, &frame->uc.uc_flags);
if (sizeof(*set) == 16) {
__put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
__put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]);
- } else {
- err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
- }
+ } else
+ err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
/* Set up to return from userspace. If provided, use a stub
already in userspace. */
if (ka->sa.sa_flags & SA_RESTORER) {
err |= __put_user(ka->sa.sa_restorer, &frame->pretcode);
} else {
- printk("%s forgot to set SA_RESTORER for signal %d.\n", me->comm, sig);
+ /* could use a vstub here */
goto give_sigsegv;
}
- if (err) {
+ if (err)
goto give_sigsegv;
- }
-#if DEBUG_SIG
+#ifdef DEBUG_SIG
printk("%d old rip %lx old rsp %lx old rax %lx\n", current->pid,regs->rip,regs->rsp,regs->rax);
#endif
/* Set up registers for signal handler */
- {
- struct exec_domain *ed = current_thread_info()->exec_domain;
- if (unlikely(ed && ed->signal_invmap && sig < 32))
- sig = ed->signal_invmap[sig];
- }
regs->rdi = sig;
/* In case the signal handler was declared without prototypes */
regs->rax = 0;
regs->rsp = (unsigned long)frame;
+ /* Set up the CS register to run signal handlers in 64-bit mode,
+ even if the handler happens to be interrupting 32-bit code. */
+ regs->cs = __USER_CS;
+
+ /* This, by contrast, has nothing to do with segment registers -
+ see include/asm-x86_64/uaccess.h for details. */
set_fs(USER_DS);
- regs->eflags &= ~TF_MASK;
-#if DEBUG_SIG
+#ifdef DEBUG_SIG
printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
current->comm, current->pid, frame, regs->rip, frame->pretcode);
#endif
- return;
+ return 0;
give_sigsegv:
- if (sig == SIGSEGV)
- ka->sa.sa_handler = SIG_DFL;
- signal_fault(regs,frame,"signal deliver");
+ force_sigsegv(sig, current);
+ return -EFAULT;
}
/*
* OK, we're invoking a handler
*/
-static void
-handle_signal(unsigned long sig, siginfo_t *info, sigset_t *oldset,
- struct pt_regs * regs)
+static int
+handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
+ sigset_t *oldset, struct pt_regs *regs)
{
- struct k_sigaction *ka = ¤t->sighand->action[sig-1];
+ int ret;
-#if DEBUG_SIG
- printk("handle_signal pid:%d sig:%lu rip:%lx rsp:%lx regs=%p\n", current->pid, sig,
+#ifdef DEBUG_SIG
+ printk("handle_signal pid:%d sig:%lu rip:%lx rsp:%lx regs=%p\n",
+ current->pid, sig,
regs->rip, regs->rsp, regs);
#endif
/* Are we from a system call? */
- if (regs->orig_rax >= 0) {
+ if ((long)regs->orig_rax >= 0) {
/* If so, check system call restarting.. */
switch (regs->rax) {
case -ERESTART_RESTARTBLOCK:
regs->rax = -EINTR;
break;
}
- /* fallthrough */
+ /* fallthrough */
case -ERESTARTNOINTR:
regs->rax = regs->orig_rax;
regs->rip -= 2;
+ break;
}
}
+ /*
+ * If TF is set due to a debugger (TIF_FORCED_TF), clear the TF flag so
+ * that register information in the sigcontext is correct.
+ */
+ if (unlikely(regs->eflags & TF_MASK)
+ && likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
+ regs->eflags &= ~TF_MASK;
+
#ifdef CONFIG_IA32_EMULATION
if (test_thread_flag(TIF_IA32)) {
if (ka->sa.sa_flags & SA_SIGINFO)
- ia32_setup_rt_frame(sig, ka, info, oldset, regs);
+ ret = ia32_setup_rt_frame(sig, ka, info, oldset, regs);
else
- ia32_setup_frame(sig, ka, oldset, regs);
+ ret = ia32_setup_frame(sig, ka, oldset, regs);
} else
#endif
- setup_rt_frame(sig, ka, info, oldset, regs);
+ ret = setup_rt_frame(sig, ka, info, oldset, regs);
- if (ka->sa.sa_flags & SA_ONESHOT)
- ka->sa.sa_handler = SIG_DFL;
-
- if (!(ka->sa.sa_flags & SA_NODEFER)) {
+ if (ret == 0) {
spin_lock_irq(¤t->sighand->siglock);
sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask);
- sigaddset(¤t->blocked,sig);
+ if (!(ka->sa.sa_flags & SA_NODEFER))
+ sigaddset(¤t->blocked,sig);
recalc_sigpending();
spin_unlock_irq(¤t->sighand->siglock);
+
+ /*
+ * Clear TF when entering the signal handler, but
+ * notify any tracer that was single-stepping it.
+ * The tracer may want to single-step inside the
+ * handler too.
+ */
+ regs->eflags &= ~TF_MASK;
+ tracehook_report_handle_signal(sig, ka, oldset, regs);
}
+
+ return ret;
}
/*
* want to handle. Thus you cannot kill init even with a SIGKILL even by
* mistake.
*/
-int do_signal(struct pt_regs *regs, sigset_t *oldset)
+static void do_signal(struct pt_regs *regs)
{
+ struct k_sigaction ka;
siginfo_t info;
int signr;
+ sigset_t *oldset;
/*
* We want the common case to go fast, which
* kernel mode. Just return without doing anything
* if so.
*/
- if ((regs->cs & 3) != 3) {
- return 1;
- }
-
- if (current->flags & PF_FREEZE) {
- refrigerator(0);
- goto no_signal;
- }
+ if (!user_mode(regs))
+ return;
- if (!oldset)
+ if (test_thread_flag(TIF_RESTORE_SIGMASK))
+ oldset = ¤t->saved_sigmask;
+ else
oldset = ¤t->blocked;
- signr = get_signal_to_deliver(&info, regs, NULL);
+ signr = get_signal_to_deliver(&info, &ka, regs, NULL);
if (signr > 0) {
/* Reenable any watchpoints before delivering the
* signal to user space. The processor register will
* inside the kernel.
*/
if (current->thread.debugreg7)
- asm volatile("movq %0,%%db7" : : "r" (current->thread.debugreg7));
+ set_debugreg(current->thread.debugreg7, 7);
/* Whee! Actually deliver the signal. */
- handle_signal(signr, &info, oldset, regs);
- return 1;
+ if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
+ /* a signal was successfully delivered; the saved
+ * sigmask will have been stored in the signal frame,
+ * and will be restored by sigreturn, so we can simply
+ * clear the TIF_RESTORE_SIGMASK flag */
+ clear_thread_flag(TIF_RESTORE_SIGMASK);
+ }
+ return;
}
- no_signal:
/* Did we come from a system call? */
- if (regs->orig_rax >= 0) {
+ if ((long)regs->orig_rax >= 0) {
/* Restart the system call - no handlers present */
long res = regs->rax;
- if (res == -ERESTARTNOHAND ||
- res == -ERESTARTSYS ||
- res == -ERESTARTNOINTR) {
+ switch (res) {
+ case -ERESTARTNOHAND:
+ case -ERESTARTSYS:
+ case -ERESTARTNOINTR:
regs->rax = regs->orig_rax;
regs->rip -= 2;
- }
- if (regs->rax == (unsigned long)-ERESTART_RESTARTBLOCK) {
- regs->rax = __NR_restart_syscall;
+ break;
+ case -ERESTART_RESTARTBLOCK:
+ regs->rax = test_thread_flag(TIF_IA32) ?
+ __NR_ia32_restart_syscall :
+ __NR_restart_syscall;
regs->rip -= 2;
+ break;
}
}
- return 0;
+
+ /* if there's no signal to deliver, we just put the saved sigmask
+ back. */
+ if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
+ clear_thread_flag(TIF_RESTORE_SIGMASK);
+ sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
+ }
}
-void do_notify_resume(struct pt_regs *regs, sigset_t *oldset, __u32 thread_info_flags)
+void
+do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
{
-#if DEBUG_SIG
+#ifdef DEBUG_SIG
printk("do_notify_resume flags:%x rip:%lx rsp:%lx caller:%lx pending:%lx\n",
thread_info_flags, regs->rip, regs->rsp, __builtin_return_address(0),signal_pending(current));
#endif
}
/* deal with pending signal delivery */
- if (thread_info_flags & _TIF_SIGPENDING)
- do_signal(regs,oldset);
+ if (thread_info_flags & (_TIF_SIGPENDING|_TIF_RESTORE_SIGMASK))
+ do_signal(regs);
}
-void signal_fault(struct pt_regs *regs, void *frame, char *where)
+void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
{
struct task_struct *me = current;
if (exception_trace)
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