linux-kernel - [PATCH 1/1] x86/entry: remove unused argument %rsi passed to exc

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Date:   Mon, 25 Sep 2023 23:13:19 -0700
From:   xin@...or.com
To:     linux-kernel@...r.kernel.org
Cc:     luto@...nel.org, tglx@...utronix.de, mingo@...hat.com,
        bp@...en8.de, dave.hansen@...ux.intel.com, x86@...nel.org,
        hpa@...or.com
Subject: [PATCH 1/1] x86/entry: remove unused argument %rsi passed to exc_nmi()

From: "Xin Li (Intel)" <xin@...or.com>

exc_nmi() only takes one argument of type struct pt_regs *, but
asm_exc_nmi() calls it with 2 arguments. The second one passed
in %rsi seems a leftover, so simply remove it.

BTW, fix 2 slips in the comments.

Signed-off-by: Xin Li (Intel) <xin@...or.com>
Acked-by: H. Peter Anvin (Intel) <hpa@...or.com>
---
 arch/x86/entry/entry_64.S | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index f71664dea1a3..9b4b512f2a75 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1163,8 +1163,8 @@ SYM_CODE_START(asm_exc_nmi)
 	 * anyway.
 	 *
 	 * To handle this case we do the following:
-	 *  Check the a special location on the stack that contains
-	 *  a variable that is set when NMIs are executing.
+	 *  Check a special location on the stack that contains a
+	 *  variable that is set when NMIs are executing.
 	 *  The interrupted task's stack is also checked to see if it
 	 *  is an NMI stack.
 	 *  If the variable is not set and the stack is not the NMI
@@ -1237,7 +1237,6 @@ SYM_CODE_START(asm_exc_nmi)
 	 */
 
 	movq	%rsp, %rdi
-	movq	$-1, %rsi
 	call	exc_nmi
 
 	/*
@@ -1295,8 +1294,8 @@ SYM_CODE_START(asm_exc_nmi)
 	 * end_repeat_nmi, then we are a nested NMI.  We must not
 	 * modify the "iret" frame because it's being written by
 	 * the outer NMI.  That's okay; the outer NMI handler is
-	 * about to about to call exc_nmi() anyway, so we can just
-	 * resume the outer NMI.
+	 * about to call exc_nmi() anyway, so we can just resume
+	 * the outer NMI.
 	 */
 
 	movq	$repeat_nmi, %rdx
@@ -1451,7 +1450,6 @@ end_repeat_nmi:
 	UNWIND_HINT_REGS
 
 	movq	%rsp, %rdi
-	movq	$-1, %rsi
 	call	exc_nmi
 
 	/* Always restore stashed SPEC_CTRL value (see paranoid_entry) */
-- 
2.40.1