diff options
Diffstat (limited to 'libc/sysdeps/linux')
| -rw-r--r-- | libc/sysdeps/linux/arm/sigaction.c | 12 | ||||
| -rw-r--r-- | libc/sysdeps/linux/arm/sigrestorer.S | 33 |
2 files changed, 34 insertions, 11 deletions
diff --git a/libc/sysdeps/linux/arm/sigaction.c b/libc/sysdeps/linux/arm/sigaction.c index 1066d33dd..8ab2be797 100644 --- a/libc/sysdeps/linux/arm/sigaction.c +++ b/libc/sysdeps/linux/arm/sigaction.c @@ -57,14 +57,7 @@ int __libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oa memcpy (&kact.sa_mask, &act->sa_mask, sizeof (sigset_t)); kact.sa_flags = act->sa_flags; # ifdef HAVE_SA_RESTORER - /* If the user specified SA_ONSTACK this means she is trying to - use the old-style stack switching. Unfortunately this - requires the sa_restorer field so we cannot install our own - handler. (In fact the user is likely to be out of luck anyway - since the kernel currently only supports stack switching via - the X/Open sigaltstack interface, but we allow for the - possibility that this might change in the future.) */ - if (kact.sa_flags & (SA_RESTORER | SA_ONSTACK)) { + if (kact.sa_flags & SA_RESTORER) { kact.sa_restorer = act->sa_restorer; } else { kact.sa_restorer = choose_restorer (kact.sa_flags); @@ -103,8 +96,7 @@ int __libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oa kact.sa_mask = act->sa_mask.__val[0]; kact.sa_flags = act->sa_flags; # ifdef HAVE_SA_RESTORER - /* See the comments above for why we test SA_ONSTACK. */ - if (kact.sa_flags & (SA_RESTORER | SA_ONSTACK)) { + if (kact.sa_flags & SA_RESTORER) { kact.sa_restorer = act->sa_restorer; } else { kact.sa_restorer = choose_restorer (kact.sa_flags); diff --git a/libc/sysdeps/linux/arm/sigrestorer.S b/libc/sysdeps/linux/arm/sigrestorer.S index bc175de6a..5b996ea83 100644 --- a/libc/sysdeps/linux/arm/sigrestorer.S +++ b/libc/sysdeps/linux/arm/sigrestorer.S @@ -20,13 +20,33 @@ /* If no SA_RESTORER function was specified by the application we use one of these. This avoids the need for the kernel to synthesise a return - instruction on the stack, which would involve expensive cache flushes. */ + instruction on the stack, which would involve expensive cache flushes. + + Nowadays (2.6 series, and somewhat earlier) the kernel uses a high page + for signal trampolines, so the cache flushes are not an issue. But since + we do not have a vDSO, continue to use these so that we can provide + unwind information. + + Start the unwind tables at least one instruction before the signal + trampoline, because the unwinder will assume we are returning after + a call site. */ .global __default_sa_restorer .type __default_sa_restorer,%function .align 2 +#ifdef __ARM_EABI__ + .fnstart + .save {r0-r15} + .pad #12 + nop +__default_sa_restorer: + mov r7, $SYS_ify(sigreturn) + swi 0x0 + .fnend +#else __default_sa_restorer: DO_CALL (sigreturn) +#endif #ifdef __NR_rt_sigreturn @@ -34,7 +54,18 @@ __default_sa_restorer: .global __default_rt_sa_restorer .type __default_rt_sa_restorer,%function .align 2 +#ifdef __ARM_EABI__ + .fnstart + .save {r0-r15} + .pad #168 + nop +__default_rt_sa_restorer: + mov r7, $SYS_ify(rt_sigreturn) + swi 0x0 + .fnend +#else __default_rt_sa_restorer: DO_CALL (rt_sigreturn) +#endif #endif |