提交 244d00b5 编写于 作者: K Kim Phillips 提交者: Borislav Petkov

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: NKim Phillips <kim.phillips@amd.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
上级 44a3918c
......@@ -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;
}
......
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