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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(&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 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(&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:[~2013-09-27  8:04 UTC|newest]

Thread overview: 36+ 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
2013-09-27  8:04 ` Jiang Liu [this message]
2013-09-27  8:04   ` [RFT PATCH v1 1/7] arm64: fix possible invalid FPSIMD initialization state Jiang Liu
2013-09-27 10:59   ` Catalin Marinas
2013-09-27 10:59     ` 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  8:04   ` Jiang Liu
2013-09-27 11:35   ` Catalin Marinas
2013-09-27 11:35     ` Catalin Marinas
2013-09-27 13:20     ` Jiang Liu
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   ` 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   ` 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   ` 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  8:04   ` Jiang Liu
2013-09-27 10:59   ` Will Deacon
2013-09-27 10:59     ` Will Deacon
2013-09-27 14:20     ` Jiang Liu
2013-09-27 14:20       ` Jiang Liu
2013-09-30  9:34       ` Will Deacon
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  8:04   ` 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 10:50   ` Catalin Marinas
2013-09-27 11:23   ` Will Deacon
2013-09-27 11:23     ` Will Deacon
2013-09-27 15:20     ` Jiang Liu
2013-09-27 15:20       ` Jiang Liu
2013-09-27 16:16       ` Catalin Marinas
2013-09-27 16:16         ` Catalin Marinas

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