From: Peter Zijlstra <peterz@infradead.org>

Date: Fri, 6 May 2022 14:14:35 +0200

Subject: x86/entry: Remove skip_r11rcx

Git-commit: 1b331eeea7b8676fc5dbdf80d0a07e41be226177

Patch-mainline: v5.19-rc1

References: bsc#1201644

Yes, r11 and rcx have been restored previously, but since they're being

popped 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>

Signed-off-by: Borislav Petkov <bp@suse.de>

Link: https://lore.kernel.org/r/20220506121631.365070674@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

@@ -153,27 +153,19 @@ For 32-bit we have the following convent

 .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

@@ -299,8 +299,7 @@ GLOBAL(entry_SYSCALL_64_after_hwframe)

 	 * 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.