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| author | Uros Bizjak <ubizjak@gmail.com> | 2023-10-17 18:27:34 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2023-10-20 12:19:51 +0200 |
| commit | 59bec00ace28d565ae0a68b23063ef3b961d82d5 (patch) | |
| tree | bfe2316d321a1703e7508c438d5290fd9ab30065 /arch/x86/include/asm/percpu.h | |
| parent | x86/percpu, xen: Correct PER_CPU_VAR() usage to include symbol and its addend (diff) | |
| download | linux-59bec00ace28d565ae0a68b23063ef3b961d82d5.tar.xz linux-59bec00ace28d565ae0a68b23063ef3b961d82d5.zip | |
x86/percpu: Introduce %rip-relative addressing to PER_CPU_VAR()
Introduce x86_64 %rip-relative addressing to the PER_CPU_VAR() macro.
Instructions using %rip-relative address operand are one byte shorter
than their absolute address counterparts and are also compatible with
position independent executable (-fpie) builds. The patch reduces
code size of a test kernel build by 150 bytes.
The PER_CPU_VAR() macro is intended to be applied to a symbol and should
not be used with register operands. Introduce the new __percpu macro and
use it in cmpxchg{8,16}b_emu.S instead.
Also add a missing function comment to this_cpu_cmpxchg8b_emu().
No functional changes intended.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: linux-kernel@vger.kernel.org
Cc: Brian Gerst <brgerst@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/x86/include/asm/percpu.h')
| -rw-r--r-- | arch/x86/include/asm/percpu.h | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h index ac3220aeb779..bbcc1ca737f0 100644 --- a/arch/x86/include/asm/percpu.h +++ b/arch/x86/include/asm/percpu.h @@ -4,17 +4,21 @@ #ifdef CONFIG_X86_64 #define __percpu_seg gs +#define __percpu_rel (%rip) #else #define __percpu_seg fs +#define __percpu_rel #endif #ifdef __ASSEMBLY__ #ifdef CONFIG_SMP -#define PER_CPU_VAR(var) %__percpu_seg:var -#else /* ! SMP */ -#define PER_CPU_VAR(var) var -#endif /* SMP */ +#define __percpu %__percpu_seg: +#else +#define __percpu +#endif + +#define PER_CPU_VAR(var) __percpu(var)__percpu_rel #ifdef CONFIG_X86_64_SMP #define INIT_PER_CPU_VAR(var) init_per_cpu__##var |