The following commit has been merged into the x86/bugs branch of tip:
Commit-ID: 55ca9010c4a988b48278f81ae4129deea52d2488
Gitweb: https://git.kernel.org/tip/55ca9010c4a988b48278f81ae4129deea52d2488
Author: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
AuthorDate: Mon, 04 Sep 2023 22:04:57 -07:00
Committer: Borislav Petkov (AMD) <bp@xxxxxxxxx>
CommitterDate: Fri, 20 Oct 2023 12:26:59 +02:00
x86/srso: Remove 'pred_cmd' label
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@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Acked-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Link: https://lore.kernel.org/r/bb20e8569cfa144def5e6f25e610804bc4974de2.1693889988.git.jpoimboe@xxxxxxxxxx
---
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 e45dd69..4f1ad23 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
|