From 6a523f6f1bd33053f56e77d2221b274227c00585 Mon Sep 17 00:00:00 2001 From: David Kaplan Date: Wed, 4 Sep 2024 10:07:11 -0500 Subject: [PATCH] x86/bugs: Fix handling when SRSO mitigation is disabled BugLink: https://bugs.launchpad.net/bugs/2089884 [ Upstream commit 1dbb6b1495d472806fef1f4c94f5b3e4c89a3c1d ] When the SRSO mitigation is disabled, either via mitigations=off or spec_rstack_overflow=off, the warning about the lack of IBPB-enhancing microcode is printed anyway. This is unnecessary since the user has turned off the mitigation. [ bp: Massage, drop SBPB rationale as it doesn't matter because when mitigations are disabled x86_pred_cmd is not being used anyway. ] Signed-off-by: David Kaplan Signed-off-by: Borislav Petkov (AMD) Acked-by: Josh Poimboeuf Link: https://lore.kernel.org/r/20240904150711.193022-1-david.kaplan@amd.com Signed-off-by: Sasha Levin Signed-off-by: Koichiro Den Signed-off-by: Roxana Nicolescu --- arch/x86/kernel/cpu/bugs.c | 14 +++++--------- 1 file changed, 5 insertions(+), 9 deletions(-) diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index e7ceee008bd0..3f96e3a2ba8a 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -2544,10 +2544,9 @@ static void __init srso_select_mitigation(void) { bool has_microcode = boot_cpu_has(X86_FEATURE_IBPB_BRTYPE); - if (cpu_mitigations_off()) - return; - - if (!boot_cpu_has_bug(X86_BUG_SRSO)) { + if (!boot_cpu_has_bug(X86_BUG_SRSO) || + cpu_mitigations_off() || + srso_cmd == SRSO_CMD_OFF) { if (boot_cpu_has(X86_FEATURE_SBPB)) x86_pred_cmd = PRED_CMD_SBPB; return; @@ -2578,11 +2577,6 @@ static void __init srso_select_mitigation(void) } switch (srso_cmd) { - case SRSO_CMD_OFF: - if (boot_cpu_has(X86_FEATURE_SBPB)) - x86_pred_cmd = PRED_CMD_SBPB; - return; - case SRSO_CMD_MICROCODE: if (has_microcode) { srso_mitigation = SRSO_MITIGATION_MICROCODE; @@ -2636,6 +2630,8 @@ static void __init srso_select_mitigation(void) pr_err("WARNING: kernel not compiled with CPU_SRSO.\n"); } break; + default: + break; } out: