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x86/srso: Remove 'pred_cmd' label

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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>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/bb20e8569cfa144def5e6f25e610804bc4974de2.1693889988.git.jpoimboe@kernel.org
This commit is contained in:
Josh Poimboeuf 2023-09-04 22:04:57 -07:00 committed by Borislav Petkov (AMD)
parent eb54be26b0
commit 55ca9010c4
1 changed files with 13 additions and 8 deletions
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21
arch/x86/kernel/cpu/bugs.c
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@ -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