[tip: objtool/core] x86/head: Mark *_start_kernel() __noreturn

[tip-bot2 for Josh Poimboeuf]

The following commit has been merged into the objtool/core branch of tip:

Commit-ID:     4208d2d79837ef70f260d6170e3ac7fd6fde7788
Gitweb:        https://git.kernel.org/tip/4208d2d79837ef70f260d6170e3ac7fd6fde7788
Author:        Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
AuthorDate:    Wed, 12 Apr 2023 16:49:33 -07:00
Committer:     Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Fri, 14 Apr 2023 17:31:24 +02:00

x86/head: Mark *_start_kernel() __noreturn

Now that start_kernel() is __noreturn, mark its chain of callers
__noreturn.

Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/c2525f96b88be98ee027ee0291d58003036d4120.1681342859.git.jpoimboe@xxxxxxxxxx
---
 arch/x86/include/asm/setup.h | 6 +++---
 arch/x86/kernel/head32.c     | 2 +-
 arch/x86/kernel/head64.c     | 4 ++--
 tools/objtool/check.c        | 2 ++
 4 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h
index f37cbff..f349562 100644
--- a/arch/x86/include/asm/setup.h
+++ b/arch/x86/include/asm/setup.h
@@ -125,11 +125,11 @@ void clear_bss(void);
 
 #ifdef __i386__
 
-asmlinkage void __init i386_start_kernel(void);
+asmlinkage void __init __noreturn i386_start_kernel(void);
 
 #else
-asmlinkage void __init x86_64_start_kernel(char *real_mode);
-asmlinkage void __init x86_64_start_reservations(char *real_mode_data);
+asmlinkage void __init __noreturn x86_64_start_kernel(char *real_mode);
+asmlinkage void __init __noreturn x86_64_start_reservations(char *real_mode_data);
 
 #endif /* __i386__ */
 #endif /* _SETUP */
diff --git a/arch/x86/kernel/head32.c b/arch/x86/kernel/head32.c
index ec6fefb..10c27b4 100644
--- a/arch/x86/kernel/head32.c
+++ b/arch/x86/kernel/head32.c
@@ -29,7 +29,7 @@ static void __init i386_default_early_setup(void)
 	x86_init.mpparse.setup_ioapic_ids = setup_ioapic_ids_from_mpc;
 }
 
-asmlinkage __visible void __init i386_start_kernel(void)
+asmlinkage __visible void __init __noreturn i386_start_kernel(void)
 {
 	/* Make sure IDT is set up before any exception happens */
 	idt_setup_early_handler();
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 387e4b1..49f7629 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -471,7 +471,7 @@ static void __init copy_bootdata(char *real_mode_data)
 	sme_unmap_bootdata(real_mode_data);
 }
 
-asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data)
+asmlinkage __visible void __init __noreturn x86_64_start_kernel(char * real_mode_data)
 {
 	/*
 	 * Build-time sanity checks on the kernel image and module
@@ -537,7 +537,7 @@ asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data)
 	x86_64_start_reservations(real_mode_data);
 }
 
-void __init x86_64_start_reservations(char *real_mode_data)
+void __init __noreturn x86_64_start_reservations(char *real_mode_data)
 {
 	/* version is always not zero if it is copied */
 	if (!boot_params.hdr.version)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 9aaad9d..a436bc1 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -225,6 +225,8 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func,
 		"start_kernel",
 		"stop_this_cpu",
 		"usercopy_abort",
+		"x86_64_start_kernel",
+		"x86_64_start_reservations",
 		"xen_cpu_bringup_again",
 		"xen_start_kernel",
 	};