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| author |   Will Deacon <will@kernel.org> | 2020-05-15 14:11:05 +0100 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2020-05-18 17:47:22 +0100 |
| commit | 51189c7a7ed1b4ed4493e27275d466ff60406d3a (patch) | |
| tree | c06448db0ce33c2d4a5ae1494806a3b81082aa96 /arch/arm64/include/asm/thread_info.h | |
| parent | efi/libstub: Disable Shadow Call Stack (diff) | |
| download | linux-dev-51189c7a7ed1b4ed4493e27275d466ff60406d3a.tar.xz linux-dev-51189c7a7ed1b4ed4493e27275d466ff60406d3a.zip | |
arm64: scs: Store absolute SCS stack pointer value in thread_info
Storing the SCS information in thread_info as a {base,offset} pair
introduces an additional load instruction on the ret-to-user path,
since the SCS stack pointer in x18 has to be converted back to an offset
by subtracting the base.
Replace the offset with the absolute SCS stack pointer value instead
and avoid the redundant load.
Tested-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/include/asm/thread_info.h')
| -rw-r--r-- | arch/arm64/include/asm/thread_info.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h index 9df79c0a4c43..6ea8b6a26ae9 100644 --- a/arch/arm64/include/asm/thread_info.h +++ b/arch/arm64/include/asm/thread_info.h @@ -43,7 +43,7 @@ struct thread_info { }; #ifdef CONFIG_SHADOW_CALL_STACK void *scs_base; - unsigned long scs_offset; + void *scs_sp; #endif }; @@ -107,7 +107,7 @@ void arch_release_task_struct(struct task_struct *tsk); #ifdef CONFIG_SHADOW_CALL_STACK #define INIT_SCS \ .scs_base = init_shadow_call_stack, \ - .scs_offset = 0, + .scs_sp = init_shadow_call_stack, #else #define INIT_SCS #endif |