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From: Jens Axboe <axboe@kernel.dk>
To: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm64: treat PF_IO_WORKER like PF_KTHREAD for mitigations
Date: Wed, 25 Jan 2023 09:43:34 -0700	[thread overview]
Message-ID: <dfc03be2-e246-ed23-6efb-fbd54a8e7781@kernel.dk> (raw)

Like PF_KTHREAD, PF_IO_WORKER never exit to userspace. They exist
entirely within the kernel, and hence don't need any task mitigations
applied.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

---

diff --git a/arch/arm64/kernel/proton-pack.c b/arch/arm64/kernel/proton-pack.c
index fca9cc6f5581..25a21c3d446c 100644
--- a/arch/arm64/kernel/proton-pack.c
+++ b/arch/arm64/kernel/proton-pack.c
@@ -654,7 +654,7 @@ static void __update_pstate_ssbs(struct pt_regs *regs, bool state)
 void spectre_v4_enable_task_mitigation(struct task_struct *tsk)
 {
 	struct pt_regs *regs = task_pt_regs(tsk);
-	bool ssbs = false, kthread = tsk->flags & PF_KTHREAD;
+	bool ssbs = false, kthread = tsk->flags & (PF_KTHREAD | PF_IO_WORKER);
 
 	if (spectre_v4_mitigations_off())
 		ssbs = true;

-- 
Jens Axboe


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             reply	other threads:[~2023-01-25 16:46 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-25 16:43 Jens Axboe [this message]
2023-01-26 14:00 ` [PATCH] arm64: treat PF_IO_WORKER like PF_KTHREAD for mitigations Will Deacon
2023-01-26 14:07   ` Jens Axboe
2023-01-26 15:04     ` Catalin Marinas
2023-03-28 14:14     ` Will Deacon
2023-03-28 16:47       ` Jens Axboe

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