x86/sev: Mark snp_abort() noreturn

Mark both the function prototype and definition as noreturn in order to prevent the compiler from doing transformations which confuse objtool like so: vmlinux.o: warning: objtool: sme_enable+0x71: unreachable instruction This triggers with gcc-12. Add it and sev_es_terminate() to the objtool noreturn tracking array too. Sort it while at it. Suggested-by: Michael Matz <[email protected]> Signed-off-by: Borislav Petkov <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Link: https://lore.kernel.org/r/[email protected]
nelseric · Aug 25, 2022 · c93c296 · c93c296
1 parent cdaa0a4
commit c93c296
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Showing 3 changed files with 20 additions and 18 deletions.
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
@@ -195,7 +195,7 @@ void snp_set_memory_shared(unsigned long vaddr, unsigned int npages);
 void snp_set_memory_private(unsigned long vaddr, unsigned int npages);
 void snp_set_wakeup_secondary_cpu(void);
 bool snp_init(struct boot_params *bp);
-void snp_abort(void);
+void __init __noreturn snp_abort(void);
 int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned long *fw_err);
 #else
 static inline void sev_es_ist_enter(struct pt_regs *regs) { }

diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
@@ -2112,7 +2112,7 @@ bool __init snp_init(struct boot_params *bp)
 	return true;
 }
 
-void __init snp_abort(void)
+void __init __noreturn snp_abort(void)
 {
 	sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
 }

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
@@ -162,32 +162,34 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func,
 
 	/*
 	 * Unfortunately these have to be hard coded because the noreturn
-	 * attribute isn't provided in ELF data.
+	 * attribute isn't provided in ELF data. Keep 'em sorted.
 	 */
 	static const char * const global_noreturns[] = {
+		"__invalid_creds",
+		"__module_put_and_kthread_exit",
+		"__reiserfs_panic",
 		"__stack_chk_fail",
-		"panic",
+		"__ubsan_handle_builtin_unreachable",
+		"cpu_bringup_and_idle",
+		"cpu_startup_entry",
 		"do_exit",
+		"do_group_exit",
 		"do_task_dead",
-		"kthread_exit",
-		"make_task_dead",
-		"__module_put_and_kthread_exit",
+		"ex_handler_msr_mce",
+		"fortify_panic",
 		"kthread_complete_and_exit",
-		"__reiserfs_panic",
+		"kthread_exit",
+		"kunit_try_catch_throw",
 		"lbug_with_loc",
-		"fortify_panic",
-		"usercopy_abort",
 		"machine_real_restart",
+		"make_task_dead",
+		"panic",
 		"rewind_stack_and_make_dead",
-		"kunit_try_catch_throw",
-		"xen_start_kernel",
-		"cpu_bringup_and_idle",
-		"do_group_exit",
+		"sev_es_terminate",
+		"snp_abort",
 		"stop_this_cpu",
-		"__invalid_creds",
-		"cpu_startup_entry",
-		"__ubsan_handle_builtin_unreachable",
-		"ex_handler_msr_mce",
+		"usercopy_abort",
+		"xen_start_kernel",
 	};
 
 	if (!func)