Messages in this thread Patch in this message | | | From | Song Shuai <> | Subject | [PATCH] riscv: vector: Check SR_SD before saving vstate | Date | Thu, 21 Dec 2023 15:04:49 +0800 |
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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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