linux-kernel - [RFC/RFT PATCH 15/19] x64/acpi: Use PIC-compatible references in wakeup

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Message-ID: <20260108092526.28586-36-ardb@kernel.org>
Date: Thu,  8 Jan 2026 09:25:42 +0000
From: Ard Biesheuvel <ardb@...nel.org>
To: linux-kernel@...r.kernel.org
Cc: x86@...nel.org,
	Ard Biesheuvel <ardb@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Josh Poimboeuf <jpoimboe@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Kees Cook <kees@...nel.org>,
	Uros Bizjak <ubizjak@...il.com>,
	Brian Gerst <brgerst@...il.com>,
	linux-hardening@...r.kernel.org
Subject: [RFC/RFT PATCH 15/19] x64/acpi: Use PIC-compatible references in wakeup_64.S

Use ordinary RIP-relative references to make the code compatible with
running the linker in PIE mode.

Note that wakeup_long64() runs in the kernel's ordinary virtual mapping
so there is no need to record the address of .Lresume_point in a global
variable. And fix the comment while at it.

Signed-off-by: Ard Biesheuvel <ardb@...nel.org>
---
 arch/x86/kernel/acpi/wakeup_64.S | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/acpi/wakeup_64.S b/arch/x86/kernel/acpi/wakeup_64.S
index 04f561f75e99..15233a4e1c95 100644
--- a/arch/x86/kernel/acpi/wakeup_64.S
+++ b/arch/x86/kernel/acpi/wakeup_64.S
@@ -14,7 +14,7 @@
 
 .code64
 	/*
-	 * Hooray, we are in Long 64-bit mode (but still running in low memory)
+	 * Hooray, we are in Long 64-bit mode
 	 */
 SYM_FUNC_START(wakeup_long64)
 	ANNOTATE_NOENDBR
@@ -41,7 +41,7 @@ SYM_FUNC_START(wakeup_long64)
 	movq	saved_rsi(%rip), %rsi
 	movq	saved_rbp(%rip), %rbp
 
-	movq	saved_rip(%rip), %rax
+	leaq	.Lresume_point(%rip), %rax
 	ANNOTATE_RETPOLINE_SAFE
 	jmp	*%rax
 SYM_FUNC_END(wakeup_long64)
@@ -52,7 +52,7 @@ SYM_FUNC_START(do_suspend_lowlevel)
 	xorl	%eax, %eax
 	call	save_processor_state
 
-	movq	$saved_context, %rax
+	leaq	saved_context(%rip), %rax
 	movq	%rsp, pt_regs_sp(%rax)
 	movq	%rbp, pt_regs_bp(%rax)
 	movq	%rsi, pt_regs_si(%rax)
@@ -71,8 +71,6 @@ 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)
@@ -90,7 +88,7 @@ SYM_FUNC_START(do_suspend_lowlevel)
 .Lresume_point:
 	ANNOTATE_NOENDBR
 	/* We don't restore %rax, it must be 0 anyway */
-	movq	$saved_context, %rax
+	leaq	saved_context(%rip), %rax
 	movq	saved_context_cr4(%rax), %rbx
 	movq	%rbx, %cr4
 	movq	saved_context_cr3(%rax), %rbx
@@ -139,7 +137,6 @@ 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)
-- 
2.47.3