From 6376306adde5b252ee7c73572e35d13fb13f6f18 Mon Sep 17 00:00:00 2001 From: "Borislav Petkov (AMD)" Date: Mon, 15 Apr 2024 18:15:43 +0200 Subject: x86/retpolines: Enable the default thunk warning only on relevant configs The using-default-thunk warning check makes sense only with configurations which actually enable the special return thunks. Otherwise, it fires on unrelated 32-bit configs on which the special return thunks won't even work (they're 64-bit only) and, what is more, those configs even go off into the weeds when booting in the alternatives patching code, leading to a dead machine. Fixes: 4461438a8405 ("x86/retpoline: Ensure default return thunk isn't used at runtime") Reported-by: Klara Modin Reported-by: Erhard Furtner Signed-off-by: Borislav Petkov (AMD) Tested-by: Klara Modin Link: https://lore.kernel.org/r/78e0d19c-b77a-4169-a80f-2eef91f4a1d6@gmail.com Link: https://lore.kernel.org/r/20240413024956.488d474e@yea --- arch/x86/lib/retpoline.S | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'arch') diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S index e674ccf720b9f..391059b2c6fbc 100644 --- a/arch/x86/lib/retpoline.S +++ b/arch/x86/lib/retpoline.S @@ -382,8 +382,15 @@ SYM_FUNC_END(call_depth_return_thunk) SYM_CODE_START(__x86_return_thunk) UNWIND_HINT_FUNC ANNOTATE_NOENDBR +#if defined(CONFIG_MITIGATION_UNRET_ENTRY) || \ + defined(CONFIG_MITIGATION_SRSO) || \ + defined(CONFIG_MITIGATION_CALL_DEPTH_TRACKING) ALTERNATIVE __stringify(ANNOTATE_UNRET_SAFE; ret), \ "jmp warn_thunk_thunk", X86_FEATURE_ALWAYS +#else + ANNOTATE_UNRET_SAFE + ret +#endif int3 SYM_CODE_END(__x86_return_thunk) EXPORT_SYMBOL(__x86_return_thunk) -- cgit 1.2.3-korg