summaryrefslogtreecommitdiff
path: root/arch/x86/kernel/signal.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86/kernel/signal.c')
-rw-r--r--arch/x86/kernel/signal.c82
1 files changed, 38 insertions, 44 deletions
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index ed37a768d0fc..d185bdd95a4b 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -61,15 +61,14 @@
regs->seg = GET_SEG(seg) | 3; \
} while (0)
-int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
- unsigned long *pax)
+int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
{
void __user *buf;
unsigned int tmpflags;
unsigned int err = 0;
/* Always make any pending restarted system calls return -EINTR */
- current_thread_info()->restart_block.fn = do_no_restart_syscall;
+ current->restart_block.fn = do_no_restart_syscall;
get_user_try {
@@ -81,7 +80,7 @@ int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
#endif /* CONFIG_X86_32 */
COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
- COPY(dx); COPY(cx); COPY(ip);
+ COPY(dx); COPY(cx); COPY(ip); COPY(ax);
#ifdef CONFIG_X86_64
COPY(r8);
@@ -94,27 +93,20 @@ int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
COPY(r15);
#endif /* CONFIG_X86_64 */
-#ifdef CONFIG_X86_32
COPY_SEG_CPL3(cs);
COPY_SEG_CPL3(ss);
-#else /* !CONFIG_X86_32 */
- /* 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. */
- COPY_SEG_CPL3(cs);
-#endif /* CONFIG_X86_32 */
get_user_ex(tmpflags, &sc->flags);
regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
regs->orig_ax = -1; /* disable syscall checks */
get_user_ex(buf, &sc->fpstate);
-
- get_user_ex(*pax, &sc->ax);
} get_user_catch(err);
err |= restore_xstate_sig(buf, config_enabled(CONFIG_X86_32));
+ force_iret();
+
return err;
}
@@ -162,8 +154,9 @@ int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
#else /* !CONFIG_X86_32 */
put_user_ex(regs->flags, &sc->flags);
put_user_ex(regs->cs, &sc->cs);
- put_user_ex(0, &sc->gs);
- put_user_ex(0, &sc->fs);
+ put_user_ex(0, &sc->__pad2);
+ put_user_ex(0, &sc->__pad1);
+ put_user_ex(regs->ss, &sc->ss);
#endif /* CONFIG_X86_32 */
put_user_ex(fpstate, &sc->fpstate);
@@ -457,9 +450,19 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig,
regs->sp = (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. */
+ /*
+ * Set up the CS and SS registers to run signal handlers in
+ * 64-bit mode, even if the handler happens to be interrupting
+ * 32-bit or 16-bit code.
+ *
+ * SS is subtle. In 64-bit mode, we don't need any particular
+ * SS descriptor, but we do need SS to be valid. It's possible
+ * that the old SS is entirely bogus -- this can happen if the
+ * signal we're trying to deliver is #GP or #SS caused by a bad
+ * SS value.
+ */
regs->cs = __USER_CS;
+ regs->ss = __USER_DS;
return 0;
}
@@ -539,7 +542,6 @@ asmlinkage unsigned long sys_sigreturn(void)
{
struct pt_regs *regs = current_pt_regs();
struct sigframe __user *frame;
- unsigned long ax;
sigset_t set;
frame = (struct sigframe __user *)(regs->sp - 8);
@@ -553,9 +555,9 @@ asmlinkage unsigned long sys_sigreturn(void)
set_current_blocked(&set);
- if (restore_sigcontext(regs, &frame->sc, &ax))
+ if (restore_sigcontext(regs, &frame->sc))
goto badframe;
- return ax;
+ return regs->ax;
badframe:
signal_fault(regs, frame, "sigreturn");
@@ -568,7 +570,6 @@ asmlinkage long sys_rt_sigreturn(void)
{
struct pt_regs *regs = current_pt_regs();
struct rt_sigframe __user *frame;
- unsigned long ax;
sigset_t set;
frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
@@ -579,13 +580,13 @@ asmlinkage long sys_rt_sigreturn(void)
set_current_blocked(&set);
- if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
+ if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
goto badframe;
if (restore_altstack(&frame->uc.uc_stack))
goto badframe;
- return ax;
+ return regs->ax;
badframe:
signal_fault(regs, frame, "rt_sigreturn");
@@ -629,7 +630,8 @@ setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
static void
handle_signal(struct ksignal *ksig, struct pt_regs *regs)
{
- bool failed;
+ bool stepping, failed;
+
/* Are we from a system call? */
if (syscall_get_nr(current, regs) >= 0) {
/* If so, check system call restarting.. */
@@ -653,12 +655,13 @@ handle_signal(struct ksignal *ksig, struct pt_regs *regs)
}
/*
- * 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 TF is set due to a debugger (TIF_FORCED_TF), clear TF now
+ * so that register information in the sigcontext is correct and
+ * then notify the tracer before entering the signal handler.
*/
- if (unlikely(regs->flags & X86_EFLAGS_TF) &&
- likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
- regs->flags &= ~X86_EFLAGS_TF;
+ stepping = test_thread_flag(TIF_SINGLESTEP);
+ if (stepping)
+ user_disable_single_step(current);
failed = (setup_rt_frame(ksig, regs) < 0);
if (!failed) {
@@ -669,19 +672,17 @@ handle_signal(struct ksignal *ksig, struct pt_regs *regs)
* it might disable possible debug exception from the
* signal handler.
*
- * 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.
+ * Clear TF for the case when it wasn't set by debugger to
+ * avoid the recursive send_sigtrap() in SIGTRAP handler.
*/
regs->flags &= ~(X86_EFLAGS_DF|X86_EFLAGS_RF|X86_EFLAGS_TF);
/*
* Ensure the signal handler starts with the new fpu state.
*/
if (used_math())
- drop_init_fpu(current);
+ fpu_reset_state(current);
}
- signal_setup_done(failed, ksig, test_thread_flag(TIF_SINGLESTEP));
+ signal_setup_done(failed, ksig, stepping);
}
#ifdef CONFIG_X86_32
@@ -740,12 +741,6 @@ do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
{
user_exit();
-#ifdef CONFIG_X86_MCE
- /* notify userspace of pending MCEs */
- if (thread_info_flags & _TIF_MCE_NOTIFY)
- mce_notify_process();
-#endif /* CONFIG_X86_64 && CONFIG_X86_MCE */
-
if (thread_info_flags & _TIF_UPROBE)
uprobe_notify_resume(regs);
@@ -786,7 +781,6 @@ asmlinkage long sys32_x32_rt_sigreturn(void)
struct pt_regs *regs = current_pt_regs();
struct rt_sigframe_x32 __user *frame;
sigset_t set;
- unsigned long ax;
frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8);
@@ -797,13 +791,13 @@ asmlinkage long sys32_x32_rt_sigreturn(void)
set_current_blocked(&set);
- if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
+ if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
goto badframe;
if (compat_restore_altstack(&frame->uc.uc_stack))
goto badframe;
- return ax;
+ return regs->ax;
badframe:
signal_fault(regs, frame, "x32 rt_sigreturn");
generated by cgit v1.2.3 (git 2.39.0) at 2024-11-09 05:52:25 +0300