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arm64: entry32: remove pointless register assignment 

We currently set x27 in compat_sys_sigreturn_wrapper and
compat_sys_rt_sigreturn_wrapper, similarly to what we do with r8/why on
32-bit ARM, in an attempt to prevent sigreturns from being restarted.

However, on arm64 we have always used pt_regs::syscallno for syscall
restarting (for both native and compat tasks), and x27 is never
inspected again before being overwritten in kernel_exit.

This patch removes the pointless register assignments.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Mark Rutland 2015-07-10 15:46:32 +01:00 committed by Catalin Marinas
parent 1b42804d27
commit ad2daa85bd
1 changed files with 0 additions and 2 deletions
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2
arch/arm64/kernel/entry32.S
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@ -32,13 +32,11 @@
ENTRY(compat_sys_sigreturn_wrapper) ENTRY(compat_sys_sigreturn_wrapper)
mov x0, sp mov x0, sp
mov x27, #0 // prevent syscall restart handling (why)
b compat_sys_sigreturn b compat_sys_sigreturn
ENDPROC(compat_sys_sigreturn_wrapper) ENDPROC(compat_sys_sigreturn_wrapper)
ENTRY(compat_sys_rt_sigreturn_wrapper) ENTRY(compat_sys_rt_sigreturn_wrapper)
mov x0, sp mov x0, sp
mov x27, #0 // prevent syscall restart handling (why)
b compat_sys_rt_sigreturn b compat_sys_rt_sigreturn
ENDPROC(compat_sys_rt_sigreturn_wrapper) ENDPROC(compat_sys_rt_sigreturn_wrapper)