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From: Brian Gerst <brgerst@gmail.com>
To: linux-kernel@vger.kernel.org, x86@kernel.org
Cc: Ingo Molnar <mingo@kernel.org>, "H . Peter Anvin" <hpa@zytor.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Borislav Petkov <bp@alien8.de>, Ard Biesheuvel <ardb@kernel.org>,
	"Rafael J . Wysocki" <rafael@kernel.org>,
	Len Brown <lenb@kernel.org>, Pavel Machek <pavel@kernel.org>,
	Brian Gerst <brgerst@gmail.com>
Subject: [PATCH v2 4/4] x86/acpi/suspend: Remove redundant register saves
Date: Tue,  3 Feb 2026 12:58:21 -0500	[thread overview]
Message-ID: <20260203175821.511847-5-brgerst@gmail.com> (raw)
In-Reply-To: <20260203175821.511847-1-brgerst@gmail.com>

All general purpose registers are saved in save_context.  Remove the
redundant saves to local data.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
---
 arch/x86/kernel/acpi/wakeup_64.S | 19 +------------------
 1 file changed, 1 insertion(+), 18 deletions(-)

diff --git a/arch/x86/kernel/acpi/wakeup_64.S b/arch/x86/kernel/acpi/wakeup_64.S
index b4bb1ca228b6..e8b3d01ba14a 100644
--- a/arch/x86/kernel/acpi/wakeup_64.S
+++ b/arch/x86/kernel/acpi/wakeup_64.S
@@ -25,19 +25,12 @@ SYM_FUNC_START(wakeup_long64)
 	movq	saved_magic(%rip), %rax
 	movq	$0x123456789abcdef0, %rdx
 	cmpq	%rdx, %rax
-	je	2f
+	je	.Lresume_point
 
 	/* stop here on a saved_magic mismatch */
 	movq $0xbad6d61676963, %rcx
 1:
 	jmp 1b
-2:
-	movq	saved_rbx(%rip), %rbx
-	movq	saved_rdi(%rip), %rdi
-	movq	saved_rsi(%rip), %rsi
-	movq	saved_rbp(%rip), %rbp
-
-	jmp	.Lresume_point
 SYM_FUNC_END(wakeup_long64)
 STACK_FRAME_NON_STANDARD wakeup_long64
 
@@ -67,11 +60,6 @@ SYM_FUNC_START(do_suspend_lowlevel)
 	movq	PER_CPU_VAR(current_task), %rax
 	movq	%rsp, TASK_threadsp(%rax)
 
-	movq	%rbp, saved_rbp(%rip)
-	movq	%rbx, saved_rbx(%rip)
-	movq	%rdi, saved_rdi(%rip)
-	movq	%rsi, saved_rsi(%rip)
-
 	movl	$3, %edi
 	xorl	%eax, %eax
 	call	x86_acpi_enter_sleep_state
@@ -120,9 +108,4 @@ SYM_FUNC_START(do_suspend_lowlevel)
 SYM_FUNC_END(do_suspend_lowlevel)
 
 .data
-saved_rbp:		.quad	0
-saved_rsi:		.quad	0
-saved_rdi:		.quad	0
-saved_rbx:		.quad	0
-
 SYM_DATA(saved_magic,	.quad	0)
-- 
2.52.0


  parent reply	other threads:[~2026-02-03 17:59 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-02-03 17:58 [PATCH v2 0/4] x86 suspend cleanups Brian Gerst
2026-02-03 17:58 ` [PATCH v2 1/4] x86/acpi/suspend: Remove indirect jump Brian Gerst
2026-02-03 17:58 ` [PATCH v2 2/4] x86/acpi/suspend: Remove segment reloads on resume Brian Gerst
2026-02-03 17:58 ` [PATCH v2 3/4] x86/acpi/suspend: Clean up stack usage Brian Gerst
2026-02-03 17:58 ` Brian Gerst [this message]
2026-02-03 20:31 ` [PATCH v2 0/4] x86 suspend cleanups Rafael J. Wysocki
2026-02-04  9:47 ` Ard Biesheuvel
2026-02-07 18:04   ` Brian Gerst

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