linux-kernel - [tip: x86/bugs] x86/bugs: Remove the X86_FEATURE_USE_IBPB check in ib_prctl

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Message-ID: <174065112356.10177.673205901241431963.tip-bot2@tip-bot2>
Date: Thu, 27 Feb 2025 10:12:03 -0000
From: "tip-bot2 for Yosry Ahmed" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Yosry Ahmed <yosry.ahmed@...ux.dev>, Ingo Molnar <mingo@...nel.org>,
 Josh Poimboeuf <jpoimboe@...nel.org>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject: [tip: x86/bugs] x86/bugs: Remove the X86_FEATURE_USE_IBPB check in
 ib_prctl_set()

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@...ux.dev>
AuthorDate:    Thu, 27 Feb 2025 01:27:09 
Committer:     Ingo Molnar <mingo@...nel.org>
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@...ux.dev>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Acked-by: Josh Poimboeuf <jpoimboe@...nel.org>
Link: https://lore.kernel.org/r/20250227012712.3193063-4-yosry.ahmed@linux.dev
---
 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: