The following commit has been merged into the x86/core branch of tip: Commit-ID: ef79ed20e3ae9ee9ac2e0f3a4e12814893972e63 Gitweb: https://git.kernel.org/tip/ef79ed20e3ae9ee9ac2e0f3a4e12814893972e63 Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx> AuthorDate: Thu, 15 Sep 2022 13:11:14 +02:00 Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx> CommitterDate: Mon, 17 Oct 2022 16:41:09 +02:00 x86/entry: Make sync_regs() invocation a tail call No point in having a call there. Spare the call/ret overhead. Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20220915111146.539578813@xxxxxxxxxxxxx --- arch/x86/entry/entry_64.S | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 5c578a7..b24b84b 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -1062,11 +1062,8 @@ SYM_CODE_START_LOCAL(error_entry) UNTRAIN_RET leaq 8(%rsp), %rdi /* arg0 = pt_regs pointer */ -.Lerror_entry_from_usermode_after_swapgs: - /* Put us onto the real thread stack. */ - call sync_regs - RET + jmp sync_regs /* * There are two places in the kernel that can potentially fault with @@ -1124,7 +1121,7 @@ SYM_CODE_START_LOCAL(error_entry) leaq 8(%rsp), %rdi /* arg0 = pt_regs pointer */ call fixup_bad_iret mov %rax, %rdi - jmp .Lerror_entry_from_usermode_after_swapgs + jmp sync_regs SYM_CODE_END(error_entry) SYM_CODE_START_LOCAL(error_return)
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