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From: Peter Zijlstra <peterz@infradead.org>
To: x86@kernel.org
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org,
	jpoimboe@redhat.com, brgerst@gmail.com, jiangshanlai@gmail.com,
	Andrew.Cooper3@citrix.com, mark.rutland@arm.com
Subject: [PATCH 4/6] x86/entry: Remove skip_r11rcx
Date: Fri, 06 May 2022 14:14:35 +0200	[thread overview]
Message-ID: <20220506121631.365070674@infradead.org> (raw)
In-Reply-To: <20220506121431.563656641@infradead.org>

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.



  parent reply	other threads:[~2022-05-06 12:21 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-06 12:14 [PATCH 0/6] x86: Various cleanups and fixes Peter Zijlstra
2022-05-06 12:14 ` [PATCH 1/6] x86/mm: Simplify RESERVE_BRK() Peter Zijlstra
2022-05-06 15:09   ` [tip: x86/asm] " tip-bot2 for Josh Poimboeuf
2022-05-06 12:14 ` [PATCH 2/6] x86/entry: Simplify entry_INT80_compat() Peter Zijlstra
2022-05-06 15:09   ` [tip: x86/asm] " tip-bot2 for Linus Torvalds
2022-05-06 12:14 ` [PATCH 3/6] x86/entry: Use PUSH_AND_CLEAR_REGS for compat Peter Zijlstra
2022-05-06 15:09   ` [tip: x86/asm] " tip-bot2 for Peter Zijlstra
2022-05-07  2:54   ` [PATCH 3/6] " Lai Jiangshan
2022-05-19 16:24   ` Guenter Roeck
2022-05-19 17:00     ` Peter Zijlstra
2022-05-19 17:11       ` Josh Poimboeuf
2022-05-19 17:35         ` Josh Poimboeuf
2022-05-20  1:11           ` Lai Jiangshan
2022-05-20  2:46             ` Guenter Roeck
2022-05-20 15:55             ` Josh Poimboeuf
2022-05-06 12:14 ` Peter Zijlstra [this message]
2022-05-06 15:09   ` [tip: x86/asm] x86/entry: Remove skip_r11rcx tip-bot2 for Peter Zijlstra
2022-05-07  2:52   ` [PATCH 4/6] " Lai Jiangshan
2022-05-06 12:14 ` [PATCH 5/6] linkage: Fix issue with missing symbol size Peter Zijlstra
2022-05-06 15:08   ` [tip: x86/asm] " tip-bot2 for Peter Zijlstra
2022-05-06 12:14 ` [PATCH 6/6] objtool: Fix STACK_FRAME_NON_STANDARD reloc type Peter Zijlstra
2022-05-06 15:08   ` [tip: x86/asm] " tip-bot2 for Peter Zijlstra
2022-05-06 16:05   ` [PATCH 6/6] " Josh Poimboeuf
2022-05-06 20:26   ` [tip: x86/asm] " tip-bot2 for Peter Zijlstra

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