From: Borislav Petkov bp@suse.de
[ Upstream commit c93c296fff6b369a7115916145047c8a3db6e27f ]
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 matz@suse.de Signed-off-by: Borislav Petkov bp@suse.de Acked-by: Peter Zijlstra peterz@infradead.org Link: https://lore.kernel.org/r/20220824152420.20547-1-bp@alien8.de Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/include/asm/sev.h | 2 +- arch/x86/kernel/sev.c | 2 +- tools/objtool/check.c | 34 ++++++++++++++++++---------------- 3 files changed, 20 insertions(+), 18 deletions(-)
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h index 4a23e52fe0ee1..ebc271bb6d8ed 100644 --- 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 index 63dc626627a03..ca4a94c7f7f76 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -2100,7 +2100,7 @@ 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 index 31c719f99f66e..5d87e0b0d85f9 100644 --- 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)