linux-user/aarch64: Add padding before __kernel_rt_sigreturn

Without this padding, an unwind through the signal handler
will pick up the unwind info for the preceding syscall.

This fixes gcc's 30_threads/thread/native_handle/cancel.cc.

Cc: qemu-stable@nongnu.org
Fixes: ee95fae075 ("linux-user/aarch64: Add vdso")
Resolves: https://linaro.atlassian.net/browse/GNU-974
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240202034427.504686-1-richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2024-02-02 13:44:27 +10:00
parent 240f46b9f2
commit 6400be014f
3 changed files with 4 additions and 0 deletions

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@ -63,7 +63,11 @@ vdso_syscall __kernel_clock_getres, __NR_clock_getres
* For now, elide the unwind info for __kernel_rt_sigreturn and rely on
* the libgcc fallback routine as we have always done. This requires
* that the code sequence used be exact.
*
* Add a nop as a spacer to ensure that unwind does not pick up the
* unwind info from the preceding syscall.
*/
nop
__kernel_rt_sigreturn:
/* No BTI C insn here -- we arrive via RET. */
mov x8, #__NR_rt_sigreturn