init: Mark start_kernel() __noreturn

Now that arch_call_rest_init() is __noreturn, mark its caller
start_kernel() __noreturn.

Signed-off-by: Josh Poimboeuf <[e-mail]>
Signed-off-by: Peter Zijlstra (Intel) <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

include/linux/start_kernel.h

···
 /* Define the prototype for start_kernel here, rather than cluttering
    up something else. */
 
-extern asmlinkage void __init start_kernel(void);
+extern asmlinkage void __init __noreturn start_kernel(void);
 extern void __init __noreturn arch_call_rest_init(void);
 extern void __ref __noreturn rest_init(void);
 

init/main.c

···
 	memblock_free(unknown_options, len);
 }
 
-asmlinkage __visible void __init __no_sanitize_address start_kernel(void)
+asmlinkage __visible void __init __no_sanitize_address __noreturn start_kernel(void)
 {
 	char *command_line;
 	char *after_dashes;

tools/objtool/check.c

···
 		"rewind_stack_and_make_dead",
 		"sev_es_terminate",
 		"snp_abort",
+		"start_kernel",
 		"stop_this_cpu",
 		"usercopy_abort",
 		"xen_cpu_bringup_again",