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| author | Will Deacon <will@kernel.org> | 2020-05-19 14:38:33 +0300 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2020-05-21 14:57:18 +0300 |
| commit | 9a964285572b5a3ea268bd744bb6837aecf09640 (patch) | |
| tree | 76d5243ccaff584ad1d4660c3ed259446bf1a4c5 /arch/arm64/kernel/vdso32 | |
| parent | e4e9f6dfeedc86afef2c3fa4102d274862fe2cf9 (diff) | |
| download | linux-9a964285572b5a3ea268bd744bb6837aecf09640.tar.xz | |
arm64: vdso: Don't prefix sigreturn trampoline with a BTI C instruction
For better or worse, GDB relies on the exact instruction sequence in the
VDSO sigreturn trampoline in order to unwind from signals correctly.
Commit c91db232da48 ("arm64: vdso: Convert to modern assembler annotations")
unfortunately added a BTI C instruction to the start of __kernel_rt_sigreturn,
which breaks this check. Thankfully, it's also not required, since the
trampoline is called from a RET instruction when returning from the signal
handler
Remove the unnecessary BTI C instruction from __kernel_rt_sigreturn,
and do the same for the 32-bit VDSO as well for good measure.
Cc: Daniel Kiss <daniel.kiss@arm.com>
Cc: Tamas Zsoldos <tamas.zsoldos@arm.com>
Reviewed-by: Dave Martin <dave.martin@arm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Fixes: c91db232da48 ("arm64: vdso: Convert to modern assembler annotations")
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/kernel/vdso32')
| -rw-r--r-- | arch/arm64/kernel/vdso32/sigreturn.S | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/arch/arm64/kernel/vdso32/sigreturn.S b/arch/arm64/kernel/vdso32/sigreturn.S index 620524969696..b36d4e2267a3 100644 --- a/arch/arm64/kernel/vdso32/sigreturn.S +++ b/arch/arm64/kernel/vdso32/sigreturn.S @@ -17,39 +17,39 @@ .save {r0-r15} .pad #COMPAT_SIGFRAME_REGS_OFFSET nop -SYM_FUNC_START(__kernel_sigreturn_arm) +SYM_CODE_START(__kernel_sigreturn_arm) mov r7, #__NR_compat_sigreturn svc #0 .fnend -SYM_FUNC_END(__kernel_sigreturn_arm) +SYM_CODE_END(__kernel_sigreturn_arm) .fnstart .save {r0-r15} .pad #COMPAT_RT_SIGFRAME_REGS_OFFSET nop -SYM_FUNC_START(__kernel_rt_sigreturn_arm) +SYM_CODE_START(__kernel_rt_sigreturn_arm) mov r7, #__NR_compat_rt_sigreturn svc #0 .fnend -SYM_FUNC_END(__kernel_rt_sigreturn_arm) +SYM_CODE_END(__kernel_rt_sigreturn_arm) .thumb .fnstart .save {r0-r15} .pad #COMPAT_SIGFRAME_REGS_OFFSET nop -SYM_FUNC_START(__kernel_sigreturn_thumb) +SYM_CODE_START(__kernel_sigreturn_thumb) mov r7, #__NR_compat_sigreturn svc #0 .fnend -SYM_FUNC_END(__kernel_sigreturn_thumb) +SYM_CODE_END(__kernel_sigreturn_thumb) .fnstart .save {r0-r15} .pad #COMPAT_RT_SIGFRAME_REGS_OFFSET nop -SYM_FUNC_START(__kernel_rt_sigreturn_thumb) +SYM_CODE_START(__kernel_rt_sigreturn_thumb) mov r7, #__NR_compat_rt_sigreturn svc #0 .fnend -SYM_FUNC_END(__kernel_rt_sigreturn_thumb) +SYM_CODE_END(__kernel_rt_sigreturn_thumb) |