From: liuj97@gmail.com (Jiang Liu)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFT PATCH v1 1/7] arm64: fix possible invalid FPSIMD initialization state
Date: Fri, 27 Sep 2013 16:04:41 +0800 [thread overview]
Message-ID: <1380269087-8520-2-git-send-email-liuj97@gmail.com> (raw)
In-Reply-To: <1380269087-8520-1-git-send-email-liuj97@gmail.com>
From: Jiang Liu <jiang.liu@huawei.com>
If context switching happens during executing fpsimd_flush_thread(),
stale value in FPSIMD registers will be saved into current thread's
fpsimd_state by fpsimd_thread_switch(). That may cause invalid
initialization state for the new process, so disable preemption
when executing fpsimd_flush_thread().
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Jiang Liu <liuj97@gmail.com>
---
arch/arm64/kernel/fpsimd.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index 1f2e4d5..bb785d2 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -80,8 +80,10 @@ void fpsimd_thread_switch(struct task_struct *next)
void fpsimd_flush_thread(void)
{
+ preempt_disable();
memset(¤t->thread.fpsimd_state, 0, sizeof(struct fpsimd_state));
fpsimd_load_state(¤t->thread.fpsimd_state);
+ preempt_enable();
}
#ifdef CONFIG_KERNEL_MODE_NEON
--
1.8.1.2
next prev parent reply other threads:[~2013-09-27 8:04 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-27 8:04 [RFT PATCH v1 0/7] enable FPSIMD lazy save and restore for arm64 Jiang Liu
2013-09-27 8:04 ` Jiang Liu [this message]
2013-09-27 10:59 ` [RFT PATCH v1 1/7] arm64: fix possible invalid FPSIMD initialization state Catalin Marinas
2013-09-27 8:04 ` [RFT PATCH v1 2/7] arm64: restore FPSIMD to default state for kernel and signal contexts Jiang Liu
2013-09-27 11:35 ` Catalin Marinas
2013-09-27 13:20 ` Jiang Liu
2013-09-27 8:04 ` [RFT PATCH v1 3/7] arm64: implement basic lazy save and restore for FPSIMD registers Jiang Liu
2013-09-27 8:04 ` [RFT PATCH v1 4/7] arm64: provide boot option "eagerfpu" to control FPSIMD restore policy Jiang Liu
2013-09-27 8:04 ` [RFT PATCH v1 5/7] arm64: reuse FPSIMD hardware context if possible Jiang Liu
2013-09-27 8:04 ` [RFT PATCH v1 6/7] amd64: avoid saving and restoring FPSIMD registers until threads access them Jiang Liu
2013-09-27 10:59 ` Will Deacon
2013-09-27 14:20 ` Jiang Liu
2013-09-30 9:34 ` Will Deacon
2013-09-27 8:04 ` [RFT PATCH v1 7/7] arm64: disable lazy load if FPSIMD registers are frequently used Jiang Liu
2013-09-27 10:50 ` [RFT PATCH v1 0/7] enable FPSIMD lazy save and restore for arm64 Catalin Marinas
2013-09-27 11:23 ` Will Deacon
2013-09-27 15:20 ` Jiang Liu
2013-09-27 16:16 ` Catalin Marinas
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