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Diffstat (limited to 'arch/x86/kernel/signal_64.c')
-rw-r--r--arch/x86/kernel/signal_64.c138
1 files changed, 67 insertions, 71 deletions
diff --git a/arch/x86/kernel/signal_64.c b/arch/x86/kernel/signal_64.c
index 1c83e5124c6..ccb2a4560c2 100644
--- a/arch/x86/kernel/signal_64.c
+++ b/arch/x86/kernel/signal_64.c
@@ -19,17 +19,28 @@
#include <linux/stddef.h>
#include <linux/personality.h>
#include <linux/compiler.h>
+#include <asm/processor.h>
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#include <asm/i387.h>
#include <asm/proto.h>
#include <asm/ia32_unistd.h>
#include <asm/mce.h>
-
-/* #define DEBUG_SIG 1 */
+#include "sigframe.h"
#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
+#define __FIX_EFLAGS (X86_EFLAGS_AC | X86_EFLAGS_OF | \
+ X86_EFLAGS_DF | X86_EFLAGS_TF | X86_EFLAGS_SF | \
+ X86_EFLAGS_ZF | X86_EFLAGS_AF | X86_EFLAGS_PF | \
+ X86_EFLAGS_CF)
+
+#ifdef CONFIG_X86_32
+# define FIX_EFLAGS (__FIX_EFLAGS | X86_EFLAGS_RF)
+#else
+# define FIX_EFLAGS __FIX_EFLAGS
+#endif
+
int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
sigset_t *set, struct pt_regs * regs);
int ia32_setup_frame(int sig, struct k_sigaction *ka,
@@ -46,16 +57,9 @@ sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
/*
* Do a signal return; undo the signal stack.
*/
-
-struct rt_sigframe
-{
- char __user *pretcode;
- struct ucontext uc;
- struct siginfo info;
-};
-
static int
-restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, unsigned long *prax)
+restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
+ unsigned long *pax)
{
unsigned int err = 0;
@@ -87,7 +91,7 @@ restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, unsigned
{
unsigned int tmpflags;
err |= __get_user(tmpflags, &sc->flags);
- regs->flags = (regs->flags & ~0x40DD5) | (tmpflags & 0x40DD5);
+ regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
regs->orig_ax = -1; /* disable syscall checks */
}
@@ -108,7 +112,7 @@ restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, unsigned
}
}
- err |= __get_user(*prax, &sc->ax);
+ err |= __get_user(*pax, &sc->ax);
return err;
badframe:
@@ -121,13 +125,11 @@ asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
sigset_t set;
unsigned long ax;
- frame = (struct rt_sigframe __user *)(regs->sp - 8);
- if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) {
+ frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
+ if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
goto badframe;
- }
- if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) {
+ if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
goto badframe;
- }
sigdelsetmask(&set, ~_BLOCKABLE);
spin_lock_irq(&current->sighand->siglock);
@@ -138,10 +140,6 @@ asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
goto badframe;
-#ifdef DEBUG_SIG
- printk("%d sigreturn ip:%lx sp:%lx frame:%p ax:%lx\n",current->pid,regs->ip,regs->sp,frame,ax);
-#endif
-
if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
goto badframe;
@@ -270,10 +268,6 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
if (err)
goto give_sigsegv;
-#ifdef DEBUG_SIG
- printk("%d old ip %lx old sp %lx old ax %lx\n", current->pid,regs->ip,regs->sp,regs->ax);
-#endif
-
/* Set up registers for signal handler */
regs->di = sig;
/* In case the signal handler was declared without prototypes */
@@ -291,18 +285,6 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
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->flags &= ~(X86_EFLAGS_TF | X86_EFLAGS_DF);
- if (test_thread_flag(TIF_SINGLESTEP))
- ptrace_notify(SIGTRAP);
-#ifdef DEBUG_SIG
- printk("SIG deliver (%s:%d): sp=%p pc=%lx ra=%p\n",
- current->comm, current->pid, frame, regs->ip, frame->pretcode);
-#endif
-
return 0;
give_sigsegv:
@@ -345,35 +327,29 @@ static long current_syscall_ret(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)
+ sigset_t *oldset, struct pt_regs *regs)
{
int ret;
-#ifdef DEBUG_SIG
- printk("handle_signal pid:%d sig:%lu ip:%lx sp:%lx regs=%p\n",
- current->pid, sig,
- regs->ip, regs->sp, regs);
-#endif
-
/* Are we from a system call? */
if (current_syscall(regs) >= 0) {
/* If so, check system call restarting.. */
switch (current_syscall_ret(regs)) {
- case -ERESTART_RESTARTBLOCK:
- case -ERESTARTNOHAND:
- regs->ax = -EINTR;
- break;
+ case -ERESTART_RESTARTBLOCK:
+ case -ERESTARTNOHAND:
+ regs->ax = -EINTR;
+ break;
- case -ERESTARTSYS:
- if (!(ka->sa.sa_flags & SA_RESTART)) {
- regs->ax = -EINTR;
- break;
- }
- /* fallthrough */
- case -ERESTARTNOINTR:
- regs->ax = regs->orig_ax;
- regs->ip -= 2;
+ case -ERESTARTSYS:
+ if (!(ka->sa.sa_flags & SA_RESTART)) {
+ regs->ax = -EINTR;
break;
+ }
+ /* fallthrough */
+ case -ERESTARTNOINTR:
+ regs->ax = regs->orig_ax;
+ regs->ip -= 2;
+ break;
}
}
@@ -396,6 +372,28 @@ handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
ret = setup_rt_frame(sig, ka, info, oldset, regs);
if (ret == 0) {
+ /*
+ * This has nothing to do with segment registers,
+ * despite the name. This magic affects uaccess.h
+ * macros' behavior. Reset it to the normal setting.
+ */
+ set_fs(USER_DS);
+
+ /*
+ * Clear the direction flag as per the ABI for function entry.
+ */
+ regs->flags &= ~X86_EFLAGS_DF;
+
+ /*
+ * 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->flags &= ~X86_EFLAGS_TF;
+ if (test_thread_flag(TIF_SINGLESTEP))
+ ptrace_notify(SIGTRAP);
+
spin_lock_irq(&current->sighand->siglock);
sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
if (!(ka->sa.sa_flags & SA_NODEFER))
@@ -420,10 +418,11 @@ static void do_signal(struct pt_regs *regs)
sigset_t *oldset;
/*
- * We want the common case to go fast, which
- * is why we may in certain cases get here from
- * kernel mode. Just return without doing anything
+ * We want the common case to go fast, which is why we may in certain
+ * cases get here from kernel mode. Just return without doing anything
* if so.
+ * X86_32: vm86 regs switched out by assembly code before reaching
+ * here, so testing against kernel CS suffices.
*/
if (!user_mode(regs))
return;
@@ -473,22 +472,19 @@ static void do_signal(struct pt_regs *regs)
}
}
- /* if there's no signal to deliver, we just put the saved sigmask
- back. */
+ /*
+ * 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, &current->saved_sigmask, NULL);
}
}
-void
-do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
+void do_notify_resume(struct pt_regs *regs, void *unused,
+ __u32 thread_info_flags)
{
-#ifdef DEBUG_SIG
- printk("do_notify_resume flags:%x ip:%lx sp:%lx caller:%p pending:%x\n",
- thread_info_flags, regs->ip, regs->sp, __builtin_return_address(0),signal_pending(current));
-#endif
-
/* Pending single-step? */
if (thread_info_flags & _TIF_SINGLESTEP) {
regs->flags |= X86_EFLAGS_TF;
@@ -502,7 +498,7 @@ do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
#endif /* CONFIG_X86_MCE */
/* deal with pending signal delivery */
- if (thread_info_flags & (_TIF_SIGPENDING|_TIF_RESTORE_SIGMASK))
+ if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
do_signal(regs);
if (thread_info_flags & _TIF_HRTICK_RESCHED)
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-14 20:38:20 +0000