Messages in this thread Patch in this message | | | From | Josh Poimboeuf <> | Subject | [PATCH v3 13/20] x86/srso: Remove 'pred_cmd' label | Date | Mon, 4 Sep 2023 22:04:57 -0700 |
| |
SBPB is only enabled in two distinct cases:
1) when SRSO has been disabled with srso=off
2) when SRSO has been fixed (in future HW)
Simplify the control flow by getting rid of the 'pred_cmd' label and moving the SBPB enablement check to the two corresponding code sites. This makes it more clear when exactly SBPB gets enabled.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> --- arch/x86/kernel/cpu/bugs.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index e45dd69aff7f..4f1ad2350f49 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -2410,13 +2410,21 @@ static void __init srso_select_mitigation(void) { bool has_microcode = boot_cpu_has(X86_FEATURE_IBPB_BRTYPE); - if (!boot_cpu_has_bug(X86_BUG_SRSO) || cpu_mitigations_off()) - goto pred_cmd; + if (cpu_mitigations_off()) + return; + + if (!boot_cpu_has_bug(X86_BUG_SRSO)) { + if (boot_cpu_has(X86_FEATURE_SBPB)) + x86_pred_cmd = PRED_CMD_SBPB; + return; + } if (has_microcode) { /* * Zen1/2 with SMT off aren't vulnerable after the right * IBPB microcode has been applied. + * + * Zen1/2 don't have SBPB, no need to try to enable it here. */ if (boot_cpu_data.x86 < 0x19 && !cpu_smt_possible()) { setup_force_cpu_cap(X86_FEATURE_SRSO_NO); @@ -2439,7 +2447,9 @@ static void __init srso_select_mitigation(void) switch (srso_cmd) { case SRSO_CMD_OFF: - goto pred_cmd; + if (boot_cpu_has(X86_FEATURE_SBPB)) + x86_pred_cmd = PRED_CMD_SBPB; + return; case SRSO_CMD_MICROCODE: if (has_microcode) { @@ -2501,11 +2511,6 @@ static void __init srso_select_mitigation(void) out: pr_info("%s\n", srso_strings[srso_mitigation]); - -pred_cmd: - if ((!boot_cpu_has_bug(X86_BUG_SRSO) || srso_cmd == SRSO_CMD_OFF) && - boot_cpu_has(X86_FEATURE_SBPB)) - x86_pred_cmd = PRED_CMD_SBPB; } #undef pr_fmt -- 2.41.0
| |