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| author | Uros Bizjak <ubizjak@gmail.com> | 2023-10-17 19:27:34 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2023-10-20 13:19:51 +0300 |
| commit | 59bec00ace28d565ae0a68b23063ef3b961d82d5 (patch) | |
| tree | bfe2316d321a1703e7508c438d5290fd9ab30065 /arch/x86/lib/cmpxchg16b_emu.S | |
| parent | aa47f90cd4331e1809d56c72fcbdbbe0a85e5992 (diff) | |
| download | linux-59bec00ace28d565ae0a68b23063ef3b961d82d5.tar.xz | |
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/lib/cmpxchg16b_emu.S')
| -rw-r--r-- | arch/x86/lib/cmpxchg16b_emu.S | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/arch/x86/lib/cmpxchg16b_emu.S b/arch/x86/lib/cmpxchg16b_emu.S index 6962df315793..4fb44894ad87 100644 --- a/arch/x86/lib/cmpxchg16b_emu.S +++ b/arch/x86/lib/cmpxchg16b_emu.S @@ -23,14 +23,14 @@ SYM_FUNC_START(this_cpu_cmpxchg16b_emu) cli /* if (*ptr == old) */ - cmpq PER_CPU_VAR(0(%rsi)), %rax + cmpq __percpu (%rsi), %rax jne .Lnot_same - cmpq PER_CPU_VAR(8(%rsi)), %rdx + cmpq __percpu 8(%rsi), %rdx jne .Lnot_same /* *ptr = new */ - movq %rbx, PER_CPU_VAR(0(%rsi)) - movq %rcx, PER_CPU_VAR(8(%rsi)) + movq %rbx, __percpu (%rsi) + movq %rcx, __percpu 8(%rsi) /* set ZF in EFLAGS to indicate success */ orl $X86_EFLAGS_ZF, (%rsp) @@ -42,8 +42,8 @@ SYM_FUNC_START(this_cpu_cmpxchg16b_emu) /* *ptr != old */ /* old = *ptr */ - movq PER_CPU_VAR(0(%rsi)), %rax - movq PER_CPU_VAR(8(%rsi)), %rdx + movq __percpu (%rsi), %rax + movq __percpu 8(%rsi), %rdx /* clear ZF in EFLAGS to indicate failure */ andl $(~X86_EFLAGS_ZF), (%rsp) |