diff options
| author | Kim Phillips <[email protected]> | 2022-02-28 11:23:15 -0600 |
|---|---|---|
| committer | Borislav Petkov <[email protected]> | 2022-02-28 18:37:08 +0100 |
| commit | 244d00b5dd4755f8df892c86cab35fb2cfd4f14b (patch) | |
| tree | 72eb087e1e58cc99734ce51e1fb022717eb3a129 | |
| parent | 44a3918c8245ab10c6c9719dd12e7a8d291980d8 (diff) | |
x86/speculation: Use generic retpoline by default on AMD
AMD retpoline may be susceptible to speculation. The speculation
execution window for an incorrect indirect branch prediction using
LFENCE/JMP sequence may potentially be large enough to allow
exploitation using Spectre V2.
By default, don't use retpoline,lfence on AMD. Instead, use the
generic retpoline.
Signed-off-by: Kim Phillips <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
| -rw-r--r-- | arch/x86/kernel/cpu/bugs.c | 9 |
1 files changed, 0 insertions, 9 deletions
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 0a4267c63d3b..a36bfe2c2480 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -941,15 +941,6 @@ static enum spectre_v2_mitigation __init spectre_v2_select_retpoline(void) return SPECTRE_V2_NONE; } - if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD || - boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) { - if (!boot_cpu_has(X86_FEATURE_LFENCE_RDTSC)) { - pr_err("LFENCE not serializing, switching to generic retpoline\n"); - return SPECTRE_V2_RETPOLINE; - } - return SPECTRE_V2_LFENCE; - } - return SPECTRE_V2_RETPOLINE; } |