From: David Kaplan Date: Mon, 7 Jul 2025 18:33:12 +0000 (-0500) Subject: x86/bugs: Add attack vector controls for SRSO X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=eda718fde6159b2e64978637ebb3f1ae98180555;p=thirdparty%2Fkernel%2Fstable.git x86/bugs: Add attack vector controls for SRSO Use attack vector controls to determine if SRSO mitigation is required. Signed-off-by: David Kaplan Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/20250707183316.1349127-18-david.kaplan@amd.com --- diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 2128623252a4..eef6ccd17c79 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -3123,14 +3123,19 @@ early_param("spec_rstack_overflow", srso_parse_cmdline); static void __init srso_select_mitigation(void) { - if (!boot_cpu_has_bug(X86_BUG_SRSO) || cpu_mitigations_off()) + if (!boot_cpu_has_bug(X86_BUG_SRSO)) { srso_mitigation = SRSO_MITIGATION_NONE; - - if (srso_mitigation == SRSO_MITIGATION_NONE) return; + } - if (srso_mitigation == SRSO_MITIGATION_AUTO) - srso_mitigation = SRSO_MITIGATION_SAFE_RET; + if (srso_mitigation == SRSO_MITIGATION_AUTO) { + if (should_mitigate_vuln(X86_BUG_SRSO)) { + srso_mitigation = SRSO_MITIGATION_SAFE_RET; + } else { + srso_mitigation = SRSO_MITIGATION_NONE; + return; + } + } /* Zen1/2 with SMT off aren't vulnerable to SRSO. */ if (boot_cpu_data.x86 < 0x19 && !cpu_smt_possible()) {