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From: Song Shuai <songshuaishuai@tinylab.org>
To: paul.walmsley@sifive.com, palmer@dabbelt.com,
	aou@eecs.berkeley.edu, andy.chiu@sifive.com,
	greentime.hu@sifive.com, conor.dooley@microchip.com,
	guoren@kernel.org, songshuaishuai@tinylab.org,
	bjorn@rivosinc.com, xiao.w.wang@intel.com, heiko@sntech.de,
	ruinland.tsai@sifive.com
Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH] riscv: vector: Check SR_SD before saving vstate
Date: Thu, 21 Dec 2023 15:04:49 +0800	[thread overview]
Message-ID: <20231221070449.1809020-1-songshuaishuai@tinylab.org> (raw)

The SD bit summarizes the dirty states of FS, VS, or XS fields,
providing a "fast check" before saving fstate or vstate.

Let __switch_to_vector() check SD bit as __switch_to_fpu() does.

Fixes: 3a2df6323def ("riscv: Add task switch support for vector")
Signed-off-by: Song Shuai <songshuaishuai@tinylab.org>
---
 arch/riscv/include/asm/vector.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/include/asm/vector.h b/arch/riscv/include/asm/vector.h
index 87aaef656257..d30fa56f67c6 100644
--- a/arch/riscv/include/asm/vector.h
+++ b/arch/riscv/include/asm/vector.h
@@ -190,7 +190,8 @@ static inline void __switch_to_vector(struct task_struct *prev,
 	struct pt_regs *regs;
 
 	regs = task_pt_regs(prev);
-	riscv_v_vstate_save(prev, regs);
+	if (unlikely(regs->status & SR_SD))
+		riscv_v_vstate_save(prev, regs);
 	riscv_v_vstate_restore(next, task_pt_regs(next));
 }
 
-- 
2.20.1


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WARNING: multiple messages have this Message-ID (diff)
From: Song Shuai <songshuaishuai@tinylab.org>
To: paul.walmsley@sifive.com, palmer@dabbelt.com,
	aou@eecs.berkeley.edu, andy.chiu@sifive.com,
	greentime.hu@sifive.com, conor.dooley@microchip.com,
	guoren@kernel.org, songshuaishuai@tinylab.org,
	bjorn@rivosinc.com, xiao.w.wang@intel.com, heiko@sntech.de,
	ruinland.tsai@sifive.com
Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH] riscv: vector: Check SR_SD before saving vstate
Date: Thu, 21 Dec 2023 15:04:49 +0800	[thread overview]
Message-ID: <20231221070449.1809020-1-songshuaishuai@tinylab.org> (raw)

The SD bit summarizes the dirty states of FS, VS, or XS fields,
providing a "fast check" before saving fstate or vstate.

Let __switch_to_vector() check SD bit as __switch_to_fpu() does.

Fixes: 3a2df6323def ("riscv: Add task switch support for vector")
Signed-off-by: Song Shuai <songshuaishuai@tinylab.org>
---
 arch/riscv/include/asm/vector.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/include/asm/vector.h b/arch/riscv/include/asm/vector.h
index 87aaef656257..d30fa56f67c6 100644
--- a/arch/riscv/include/asm/vector.h
+++ b/arch/riscv/include/asm/vector.h
@@ -190,7 +190,8 @@ static inline void __switch_to_vector(struct task_struct *prev,
 	struct pt_regs *regs;
 
 	regs = task_pt_regs(prev);
-	riscv_v_vstate_save(prev, regs);
+	if (unlikely(regs->status & SR_SD))
+		riscv_v_vstate_save(prev, regs);
 	riscv_v_vstate_restore(next, task_pt_regs(next));
 }
 
-- 
2.20.1


             reply	other threads:[~2023-12-21  7:06 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-12-21  7:04 Song Shuai [this message]
2023-12-21  7:04 ` [PATCH] riscv: vector: Check SR_SD before saving vstate Song Shuai
2023-12-21  7:37 ` Wang, Xiao W
2023-12-21  7:37   ` Wang, Xiao W
2023-12-21  7:54   ` Andy Chiu
2023-12-21  7:54     ` Andy Chiu
2024-01-11 14:50 ` patchwork-bot+linux-riscv
2024-01-11 14:50   ` patchwork-bot+linux-riscv
2024-01-11 15:16   ` Andy Chiu
2024-01-11 15:16     ` Andy Chiu
2024-01-11 15:36     ` Palmer Dabbelt
2024-01-11 15:36       ` Palmer Dabbelt

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