Commit 1dbb6b14 authored by David Kaplan's avatar David Kaplan Committed by Borislav Petkov (AMD)
Browse files

x86/bugs: Fix handling when SRSO mitigation is disabled 



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: default avatarDavid Kaplan <david.kaplan@amd.com>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Acked-by: default avatarJosh Poimboeuf <jpoimboe@kernel.org>
Link: https://lore.kernel.org/r/20240904150711.193022-1-david.kaplan@amd.com
parent 23e12b54

arch/x86/kernel/cpu/bugs.c

+5 −9
Original line number Diff line number Diff line
@@ -2557,10 +2557,9 @@ 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;
@@ -2591,11 +2590,6 @@ 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;
@@ -2649,6 +2643,8 @@ static void __init srso_select_mitigation(void) 
			pr_err("WARNING: kernel not compiled with MITIGATION_SRSO.\n");

                }

		break;

	default:

		break;

	}



out: