Commit c93c296f authored by Borislav Petkov's avatar Borislav Petkov
Browse files

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: default avatarMichael Matz <matz@suse.de>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220824152420.20547-1-bp@alien8.de
parent cdaa0a40

arch/x86/include/asm/sev.h

+1 −1
Original line number Diff line number Diff line
@@ -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) { }

arch/x86/kernel/sev.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

}

tools/objtool/check.c

+18 −16
Original line number Diff line number Diff line
@@ -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)