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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 1/4] x86/acpi/suspend: Remove indirect jump
Date: Tue,  3 Feb 2026 12:58:18 -0500	[thread overview]
Message-ID: <20260203175821.511847-2-brgerst@gmail.com> (raw)
In-Reply-To: <20260203175821.511847-1-brgerst@gmail.com>

wakeup_long64() is called from common_startup_64() via initial_code, so
it is already running on the normal virtual mapping.  There is no need
to use an indirect jump since it is not switching mappings.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
---
 arch/x86/kernel/acpi/wakeup_64.S | 11 ++---------
 1 file changed, 2 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kernel/acpi/wakeup_64.S b/arch/x86/kernel/acpi/wakeup_64.S
index 04f561f75e99..3d56610f0108 100644
--- a/arch/x86/kernel/acpi/wakeup_64.S
+++ b/arch/x86/kernel/acpi/wakeup_64.S
@@ -41,10 +41,9 @@ SYM_FUNC_START(wakeup_long64)
 	movq	saved_rsi(%rip), %rsi
 	movq	saved_rbp(%rip), %rbp
 
-	movq	saved_rip(%rip), %rax
-	ANNOTATE_RETPOLINE_SAFE
-	jmp	*%rax
+	jmp	.Lresume_point
 SYM_FUNC_END(wakeup_long64)
+STACK_FRAME_NON_STANDARD wakeup_long64
 
 SYM_FUNC_START(do_suspend_lowlevel)
 	FRAME_BEGIN
@@ -71,8 +70,6 @@ SYM_FUNC_START(do_suspend_lowlevel)
 	pushfq
 	popq	pt_regs_flags(%rax)
 
-	movq	$.Lresume_point, saved_rip(%rip)
-
 	movq	%rsp, saved_rsp(%rip)
 	movq	%rbp, saved_rbp(%rip)
 	movq	%rbx, saved_rbx(%rip)
@@ -84,11 +81,8 @@ SYM_FUNC_START(do_suspend_lowlevel)
 	xorl	%eax, %eax
 	call	x86_acpi_enter_sleep_state
 	/* in case something went wrong, restore the machine status and go on */
-	jmp	.Lresume_point
 
-	.align 4
 .Lresume_point:
-	ANNOTATE_NOENDBR
 	/* We don't restore %rax, it must be 0 anyway */
 	movq	$saved_context, %rax
 	movq	saved_context_cr4(%rax), %rbx
@@ -139,7 +133,6 @@ saved_rsi:		.quad	0
 saved_rdi:		.quad	0
 saved_rbx:		.quad	0
 
-saved_rip:		.quad	0
 saved_rsp:		.quad	0
 
 SYM_DATA(saved_magic,	.quad	0)
-- 
2.52.0


  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 ` Brian Gerst [this message]
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 ` [PATCH v2 4/4] x86/acpi/suspend: Remove redundant register saves Brian Gerst
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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