diff options
Diffstat (limited to 'arch/x86/lib')
| -rw-r--r-- | arch/x86/lib/retpoline.S | 15 |
1 files changed, 6 insertions, 9 deletions
diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S index 0045153ba222..721b528da9ac 100644 --- a/arch/x86/lib/retpoline.S +++ b/arch/x86/lib/retpoline.S @@ -369,19 +369,16 @@ SYM_FUNC_END(call_depth_return_thunk) * 'JMP __x86_return_thunk' sites are changed to something else by * apply_returns(). * - * This should be converted eventually to call a warning function which - * should scream loudly when the default return thunk is called after - * alternatives have been applied. - * - * That warning function cannot BUG() because the bug splat cannot be - * displayed in all possible configurations, leading to users not really - * knowing why the machine froze. + * The ALTERNATIVE below adds a really loud warning to catch the case + * where the insufficient default return thunk ends up getting used for + * whatever reason like miscompilation or failure of + * objtool/alternatives/etc to patch all the return sites. */ SYM_CODE_START(__x86_return_thunk) UNWIND_HINT_FUNC ANNOTATE_NOENDBR - ANNOTATE_UNRET_SAFE - ret + ALTERNATIVE __stringify(ANNOTATE_UNRET_SAFE; ret), \ + "jmp warn_thunk_thunk", X86_FEATURE_ALWAYS int3 SYM_CODE_END(__x86_return_thunk) EXPORT_SYMBOL(__x86_return_thunk) |