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From: liuj97@gmail.com (Jiang Liu)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFT PATCH v2 1/4] arm64: fix possible invalid FPSIMD initialization state
Date: Sun, 13 Oct 2013 22:20:17 +0800	[thread overview]
Message-ID: <1381674029-430-1-git-send-email-liuj97@gmail.com> (raw)

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(&current->thread.fpsimd_state, 0, sizeof(struct fpsimd_state));
 	fpsimd_load_state(&current->thread.fpsimd_state);
+	preempt_enable();
 }
 
 #ifdef CONFIG_KERNEL_MODE_NEON
-- 
1.8.1.2

WARNING: multiple messages have this Message-ID (diff)
From: Jiang Liu <liuj97@gmail.com>
To: Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	Jiang Liu <jiang.liu@huawei.com>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Cc: Jiang Liu <liuj97@gmail.com>
Subject: [RFT PATCH v2 1/4] arm64: fix possible invalid FPSIMD initialization state
Date: Sun, 13 Oct 2013 22:20:17 +0800	[thread overview]
Message-ID: <1381674029-430-1-git-send-email-liuj97@gmail.com> (raw)

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(&current->thread.fpsimd_state, 0, sizeof(struct fpsimd_state));
 	fpsimd_load_state(&current->thread.fpsimd_state);
+	preempt_enable();
 }
 
 #ifdef CONFIG_KERNEL_MODE_NEON
-- 
1.8.1.2


             reply	other threads:[~2013-10-13 14:20 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-13 14:20 Jiang Liu [this message]
2013-10-13 14:20 ` [RFT PATCH v2 1/4] arm64: fix possible invalid FPSIMD initialization state Jiang Liu
2013-10-13 14:20 ` [RFT PATCH v2 2/4] arm64: restore FPSIMD to default state for kernel and signal contexts Jiang Liu
2013-10-13 14:20   ` Jiang Liu
2013-10-14 15:16   ` Will Deacon
2013-10-14 15:16     ` Will Deacon
2013-10-14 15:30     ` Jiang Liu
2013-10-14 15:30       ` Jiang Liu
2013-10-14 15:39       ` Will Deacon
2013-10-14 15:39         ` Will Deacon
2013-10-14 15:50         ` Jiang Liu
2013-10-14 15:50           ` Jiang Liu
2013-10-14 15:23   ` Catalin Marinas
2013-10-14 15:23     ` Catalin Marinas
2013-10-13 14:20 ` [RFT PATCH v2 3/4] arm64: reduce duplicated code when saving/restoring FPSIMD for signal handling Jiang Liu
2013-10-13 14:20   ` Jiang Liu
2013-10-14 15:44   ` Catalin Marinas
2013-10-14 15:44     ` Catalin Marinas
2013-10-14 16:01     ` Jiang Liu
2013-10-14 16:01       ` Jiang Liu
2013-10-13 14:20 ` [RFT PATCH v2 4/4] arm64: reuse FPSIMD hardware context if possible Jiang Liu
2013-10-13 14:20   ` Jiang Liu
2013-10-14 13:54 ` [RFT PATCH v2 1/4] arm64: fix possible invalid FPSIMD initialization state Catalin Marinas
2013-10-14 13:54   ` Catalin Marinas
2013-10-14 13:58   ` Jiang Liu
2013-10-14 13:58     ` Jiang Liu

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