[tip: x86/bugs] x86/bugs: Remove the X86_FEATURE_USE_IBPB check in ib_prctl_set()

From: tip-bot2 for Yosry Ahmed
Date: Thu Feb 27 2025 - 05:12:42 EST


The following commit has been merged into the x86/bugs branch of tip:

Commit-ID: bd9a8542ceccce1b1d5d5fd5e47be57fe42f9bb9
Gitweb: https://git.kernel.org/tip/bd9a8542ceccce1b1d5d5fd5e47be57fe42f9bb9
Author: Yosry Ahmed <yosry.ahmed@xxxxxxxxx>
AuthorDate: Thu, 27 Feb 2025 01:27:09
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Thu, 27 Feb 2025 10:57:20 +01:00

x86/bugs: Remove the X86_FEATURE_USE_IBPB check in ib_prctl_set()

If X86_FEATURE_USE_IBPB is not set, then both spectre_v2_user_ibpb and
spectre_v2_user_stibp are set to SPECTRE_V2_USER_NONE in
spectre_v2_user_select_mitigation(). Since ib_prctl_set() already checks
for this before performing the IBPB, the X86_FEATURE_USE_IBPB check is
redundant. Remove it.

Signed-off-by: Yosry Ahmed <yosry.ahmed@xxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Acked-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20250227012712.3193063-4-yosry.ahmed@xxxxxxxxx
---
arch/x86/kernel/cpu/bugs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 754150f..1d7afc4 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -2272,7 +2272,7 @@ static int ib_prctl_set(struct task_struct *task, unsigned long ctrl)
if (ctrl == PR_SPEC_FORCE_DISABLE)
task_set_spec_ib_force_disable(task);
task_update_spec_tif(task);
- if (task == current && cpu_feature_enabled(X86_FEATURE_USE_IBPB))
+ if (task == current)
indirect_branch_prediction_barrier();
break;
default: