Messages in this thread Patch in this message | | | Date | Fri, 06 May 2022 14:14:35 +0200 | From | Peter Zijlstra <> | Subject | [PATCH 4/6] x86/entry: Remove skip_r11rcx |
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Yes, r11 and rcx have been restored previously, but since we're popping them anyway (into rsi) might as well pop them into their own regs -- setting them to the value they already are.
Less magical code.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- arch/x86/entry/calling.h | 10 +--------- arch/x86/entry/entry_64.S | 3 +-- 2 files changed, 2 insertions(+), 11 deletions(-)
--- a/arch/x86/entry/calling.h +++ b/arch/x86/entry/calling.h @@ -120,27 +120,19 @@ For 32-bit we have the following convent CLEAR_REGS .endm -.macro POP_REGS pop_rdi=1 skip_r11rcx=0 +.macro POP_REGS pop_rdi=1 popq %r15 popq %r14 popq %r13 popq %r12 popq %rbp popq %rbx - .if \skip_r11rcx - popq %rsi - .else popq %r11 - .endif popq %r10 popq %r9 popq %r8 popq %rax - .if \skip_r11rcx - popq %rsi - .else popq %rcx - .endif popq %rdx popq %rsi .if \pop_rdi --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -191,8 +191,7 @@ SYM_INNER_LABEL(entry_SYSCALL_64_after_h * perf profiles. Nothing jumps here. */ syscall_return_via_sysret: - /* rcx and r11 are already restored (see code above) */ - POP_REGS pop_rdi=0 skip_r11rcx=1 + POP_REGS pop_rdi=0 /* * Now all regs are restored except RSP and RDI.
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