diff options
Diffstat (limited to 'libc/sysdeps/linux/arm/sigrestorer.S')
| -rw-r--r-- | libc/sysdeps/linux/arm/sigrestorer.S | 33 |
1 files changed, 32 insertions, 1 deletions
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 |