From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Xie Yuanbin <xieyuanbin1@huawei.com>
Cc: rmk+kernel@armlinux.org.uk, linux@armlinux.org.uk,
rppt@kernel.org, vbabka@suse.cz, pfalcato@suse.de,
brauner@kernel.org, lorenzo.stoakes@oracle.com,
kuninori.morimoto.gx@renesas.com, tony@atomide.com,
arnd@arndb.de, akpm@linux-foundation.org, punitagrawal@gmail.com,
rjw@rjwysocki.net, marc.zyngier@arm.com, will@kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, liaohua4@huawei.com,
lilinjie8@huawei.com
Subject: Re: [PATCH v2 RESEND 1/2] ARM: spectre-v2: Fix potential missing mitigations
Date: Tue, 28 Oct 2025 17:28:25 +0100 [thread overview]
Message-ID: <20251028162825.x-4ryn3p@linutronix.de> (raw)
In-Reply-To: <20251028162005.bLKC89Hy@linutronix.de>
On 2025-10-28 17:20:06 [+0100], To Xie Yuanbin wrote:
> The requirement is to invoke the mitigation callback of the right CPU.
> What about disabling preemption before getting the callback and doing
> the invocation?
Something like this:
diff --git a/arch/arm/include/asm/system_misc.h b/arch/arm/include/asm/system_misc.h
--- a/arch/arm/include/asm/system_misc.h
+++ b/arch/arm/include/asm/system_misc.h
@@ -20,8 +20,10 @@ typedef void (*harden_branch_predictor_fn_t)(void);
DECLARE_PER_CPU(harden_branch_predictor_fn_t, harden_branch_predictor_fn);
static inline void harden_branch_predictor(void)
{
- harden_branch_predictor_fn_t fn = per_cpu(harden_branch_predictor_fn,
- smp_processor_id());
+ harden_branch_predictor_fn_t fn;
+
+ guard(preempt)();
+ fn = per_cpu(harden_branch_predictor_fn, smp_processor_id());
if (fn)
fn();
}
Sebastian
next prev parent reply other threads:[~2025-10-28 16:28 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-16 12:16 [PATCH v2 RESEND 1/2] ARM: spectre-v2: Fix potential missing mitigations Xie Yuanbin
2025-10-16 12:16 ` [PATCH v2 RESEND 2/2] ARM: mm: Optimize page_fault to reduce the impact of spectre-v2 bugfix Xie Yuanbin
2025-10-28 16:20 ` [PATCH v2 RESEND 1/2] ARM: spectre-v2: Fix potential missing mitigations Sebastian Andrzej Siewior
2025-10-28 16:28 ` Sebastian Andrzej Siewior [this message]
2025-10-28 18:20 ` Sebastian Andrzej Siewior
2025-10-29 2:41 ` Xie Yuanbin
2025-10-29 7:11 ` Sebastian Andrzej Siewior
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