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| author | Borislav Petkov (AMD) <bp@alien8.de> | 2024-04-15 18:15:43 +0200 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2024-04-17 18:02:05 +0200 |
| commit | 6376306adde5b252ee7c73572e35d13fb13f6f18 (patch) | |
| tree | cf8dce67fa3fec89d162638ae8cb8ad379eea0f9 | |
| parent | x86/bugs: Fix BHI retpoline check (diff) | |
| download | linux-6376306adde5b252ee7c73572e35d13fb13f6f18.tar.xz linux-6376306adde5b252ee7c73572e35d13fb13f6f18.zip | |
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 <klarasmodin@gmail.com>
Reported-by: Erhard Furtner <erhard_f@mailbox.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Klara Modin <klarasmodin@gmail.com>
Link: https://lore.kernel.org/r/78e0d19c-b77a-4169-a80f-2eef91f4a1d6@gmail.com
Link: https://lore.kernel.org/r/20240413024956.488d474e@yea
| -rw-r--r-- | arch/x86/lib/retpoline.S | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S index e674ccf720b9..391059b2c6fb 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) |