(dropping stable@ from Cc).
---
Merge the test whether the CPU supports STIBP into the test which
determines whether STIBP is required. Thus try to simplify what is
already an insane logic.
Remove a superfluous newline in a comment, while at it.
Signed-off-by: Borislav Petkov <b...@suse.de>
Cc: Anthony Steinhauser <asteinhau...@google.com>
---
arch/x86/kernel/cpu/bugs.c | 13 ++++---------
1 file changed, 4 insertions(+), 9 deletions(-)
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 0b71970d2d3d..7beaefa9d198 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -763,10 +763,12 @@ spectre_v2_user_select_mitigation(enum
spectre_v2_mitigation_cmd v2_cmd)
}
/*
- * If enhanced IBRS is enabled or SMT impossible, STIBP is not
+ * If no STIBP, enhanced IBRS is enabled or SMT impossible, STIBP is not
* required.
*/
- if (!smt_possible || spectre_v2_enabled == SPECTRE_V2_IBRS_ENHANCED)
+ if (!boot_cpu_has(X86_FEATURE_STIBP) ||
+ !smt_possible ||
+ spectre_v2_enabled == SPECTRE_V2_IBRS_ENHANCED)
return;
/*
@@ -778,12 +780,6 @@ spectre_v2_user_select_mitigation(enum
spectre_v2_mitigation_cmd v2_cmd)
boot_cpu_has(X86_FEATURE_AMD_STIBP_ALWAYS_ON))
mode = SPECTRE_V2_USER_STRICT_PREFERRED;
- /*
- * If STIBP is not available, clear the STIBP mode.
- */
- if (!boot_cpu_has(X86_FEATURE_STIBP))
- mode = SPECTRE_V2_USER_NONE;
-
spectre_v2_user_stibp = mode;
set_mode:
@@ -1270,7 +1266,6 @@ static int ib_prctl_set(struct task_struct *task,
unsigned long ctrl)
* Indirect branch speculation is always disabled in strict
* mode. It can neither be enabled if it was force-disabled
* by a previous prctl call.
-
*/
if (spectre_v2_user_ibpb == SPECTRE_V2_USER_STRICT ||
spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT ||
--
2.21.0
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
