From: Christoph Hellwig <hch@infradead.org>
To: Vincent Chen <vincent.chen@sifive.com>
Cc: linux-riscv@lists.infradead.org, palmer@sifive.com,
linux-kernel@vger.kernel.org, aou@eecs.berkeley.edu,
paul.walmsley@sifive.com
Subject: Re: [PATCH 1/2] riscv: Correct the initialized flow of FP register
Date: Mon, 12 Aug 2019 07:58:16 -0700 [thread overview]
Message-ID: <20190812145816.GD26897@infradead.org> (raw)
In-Reply-To: <1565251121-28490-2-git-send-email-vincent.chen@sifive.com>
> +static inline void fstate_off(struct task_struct *task,
> + struct pt_regs *regs)
> +{
> + regs->sstatus = (regs->sstatus & ~(SR_FS)) | SR_FS_OFF;
No need for the inner braces here.
> +}
> +
> static inline void fstate_save(struct task_struct *task,
> struct pt_regs *regs)
> {
> diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
> index f23794b..e3077ee 100644
> --- a/arch/riscv/kernel/process.c
> +++ b/arch/riscv/kernel/process.c
> @@ -64,8 +64,16 @@ void start_thread(struct pt_regs *regs, unsigned long pc,
> unsigned long sp)
> {
> regs->sstatus = SR_SPIE;
> - if (has_fpu)
> + if (has_fpu) {
> regs->sstatus |= SR_FS_INITIAL;
> +#ifdef CONFIG_FPU
> + /*
> + * Restore the initial value to the FP register
> + * before starting the user program.
> + */
> + fstate_restore(current, regs);
> +#endif
fstate_restore has a no-op stub for the !CONFIG_FPU case, so the ifdef
here is not needed.
Otherwise this looks good to me:
Reviewed-by: Christoph Hellwig <hch@lst.de>
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next prev parent reply other threads:[~2019-08-12 14:58 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-08 7:58 [PATCH 0/2] riscv: Correct the initialized flow of FP and __fstate_clean() Vincent Chen
2019-08-08 7:58 ` [PATCH 1/2] riscv: Correct the initialized flow of FP register Vincent Chen
2019-08-08 10:15 ` Anup Patel
2019-08-08 15:50 ` Paul Walmsley
2019-08-14 1:45 ` Vincent Chen
2019-08-14 3:51 ` Anup Patel
2019-08-12 14:58 ` Christoph Hellwig [this message]
2019-08-14 1:52 ` Vincent Chen
2019-08-08 7:58 ` [PATCH 2/2] riscv: Make __fstate_clean() can work correctly Vincent Chen
2019-08-08 10:17 ` Anup Patel
2019-08-14 1:55 ` Vincent Chen
2019-08-12 14:59 ` Christoph Hellwig
2019-08-14 1:55 ` Vincent Chen
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