linux-kernel - [tip: x86/boot] x86/kexec: Use typedef for relocate_kernel

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Message-ID: <173693267099.31546.3766901516400980865.tip-bot2@tip-bot2>
Date: Wed, 15 Jan 2025 09:17:50 -0000
From: "tip-bot2 for David Woodhouse" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: David Woodhouse <dwmw@...zon.co.uk>,
 "Borislav Petkov (AMD)" <bp@...en8.de>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject: [tip: x86/boot] x86/kexec: Use typedef for relocate_kernel_fn
 function prototype

The following commit has been merged into the x86/boot branch of tip:

Commit-ID:     7c61a3d8f7a8cf0f0cbdc8459dd86782ba7285f1
Gitweb:        https://git.kernel.org/tip/7c61a3d8f7a8cf0f0cbdc8459dd86782ba7285f1
Author:        David Woodhouse <dwmw@...zon.co.uk>
AuthorDate:    Thu, 09 Jan 2025 14:04:21 
Committer:     Borislav Petkov (AMD) <bp@...en8.de>
CommitterDate: Tue, 14 Jan 2025 13:09:08 +01:00

x86/kexec: Use typedef for relocate_kernel_fn function prototype

Both i386 and x86_64 now copy the relocate_kernel() function into the control
page and execute it from there, using an open-coded function pointer.

Use a typedef for it instead.

  [ bp: Put relocate_kernel_ptr ptr arithmetic on a single line. ]

Signed-off-by: David Woodhouse <dwmw@...zon.co.uk>
Signed-off-by: Borislav Petkov (AMD) <bp@...en8.de>
Link: https://lore.kernel.org/r/20250109140757.2841269-10-dwmw2@infradead.org
---
 arch/x86/include/asm/kexec.h       | 26 +++++++++++++-------------
 arch/x86/kernel/machine_kexec_32.c |  7 +------
 arch/x86/kernel/machine_kexec_64.c |  9 ++-------
 3 files changed, 16 insertions(+), 26 deletions(-)

diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index 48e4f44..8ad1874 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -111,21 +111,21 @@ static inline void crash_setup_regs(struct pt_regs *newregs,
 }
 
 #ifdef CONFIG_X86_32
-asmlinkage unsigned long
-relocate_kernel(unsigned long indirection_page,
-		unsigned long control_page,
-		unsigned long start_address,
-		unsigned int has_pae,
-		unsigned int preserve_context);
+typedef asmlinkage unsigned long
+relocate_kernel_fn(unsigned long indirection_page,
+		   unsigned long control_page,
+		   unsigned long start_address,
+		   unsigned int has_pae,
+		   unsigned int preserve_context);
 #else
-unsigned long
-relocate_kernel(unsigned long indirection_page,
-		unsigned long pa_control_page,
-		unsigned long start_address,
-		unsigned int preserve_context,
-		unsigned int host_mem_enc_active);
+typedef unsigned long
+relocate_kernel_fn(unsigned long indirection_page,
+		   unsigned long pa_control_page,
+		   unsigned long start_address,
+		   unsigned int preserve_context,
+		   unsigned int host_mem_enc_active);
 #endif
-
+extern relocate_kernel_fn relocate_kernel;
 #define ARCH_HAS_KIMAGE_ARCH
 
 #ifdef CONFIG_X86_32
diff --git a/arch/x86/kernel/machine_kexec_32.c b/arch/x86/kernel/machine_kexec_32.c
index 1b373d7..8026516 100644
--- a/arch/x86/kernel/machine_kexec_32.c
+++ b/arch/x86/kernel/machine_kexec_32.c
@@ -160,15 +160,10 @@ void machine_kexec_cleanup(struct kimage *image)
  */
 void machine_kexec(struct kimage *image)
 {
+	relocate_kernel_fn *relocate_kernel_ptr;
 	unsigned long page_list[PAGES_NR];
 	void *control_page;
 	int save_ftrace_enabled;
-	asmlinkage unsigned long
-		(*relocate_kernel_ptr)(unsigned long indirection_page,
-				       unsigned long control_page,
-				       unsigned long start_address,
-				       unsigned int has_pae,
-				       unsigned int preserve_context);
 
 #ifdef CONFIG_KEXEC_JUMP
 	if (image->preserve_context)
diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index 1440f79..a68f5a0 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -344,12 +344,8 @@ void machine_kexec_cleanup(struct kimage *image)
  */
 void __nocfi machine_kexec(struct kimage *image)
 {
-	unsigned long (*relocate_kernel_ptr)(unsigned long indirection_page,
-					     unsigned long pa_control_page,
-					     unsigned long start_address,
-					     unsigned int preserve_context,
-					     unsigned int host_mem_enc_active);
 	unsigned long reloc_start = (unsigned long)__relocate_kernel_start;
+	relocate_kernel_fn *relocate_kernel_ptr;
 	unsigned int host_mem_enc_active;
 	int save_ftrace_enabled;
 	void *control_page;
@@ -391,8 +387,7 @@ void __nocfi machine_kexec(struct kimage *image)
 	 * Allow for the possibility that relocate_kernel might not be at
 	 * the very start of the page.
 	 */
-	relocate_kernel_ptr = control_page + (unsigned long)relocate_kernel -
-		reloc_start;
+	relocate_kernel_ptr = control_page + (unsigned long)relocate_kernel - reloc_start;
 
 	/*
 	 * The segment registers are funny things, they have both a