linux-kernel - Re: [PATCH] LoongArch: Fix missing fcsr in ptrace's fpr

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Message-ID: <6bc55cd5-bb6e-8d4a-79ec-4555c0b7765b@microchip.com>
Date:   Thu, 14 Jul 2022 06:51:09 +0000
From:   <Conor.Dooley@...rochip.com>
To:     <huqi@...ngson.cn>, <chenhuacai@...nel.org>, <kernel@...0n.name>,
        <oleg@...hat.com>
CC:     <lixu@...ngson.cn>, <loongarch@...ts.linux.dev>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] LoongArch: Fix missing fcsr in ptrace's fpr_set

On 14/07/2022 07:25, Qi Hu wrote:
> In file ptrace.c, function fpr_set does not copy fcsr data from ubuf
> to kbuf. That's the reason why fcsr cannot be modified by ptrace.
> 
> This patch fixs this problem and allows users using ptrace to modify
> the fcsr.
> 
> Signed-off-by: Qi Hu <huqi@...ngson.cn>
> Signed-off-by: Xu Li <lixu@...ngson.cn>

Hey Qi Hu,

Why does this have Xu Li's SoB if they're neither the author nor listed
as a Co-developed-by:?

As submitter, your SoB should be last anyway.
Thanks,
Conor.

> ---
>   arch/loongarch/kernel/ptrace.c | 12 +++++++-----
>   1 file changed, 7 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/loongarch/kernel/ptrace.c b/arch/loongarch/kernel/ptrace.c
> index e6ab87948e1d..dc2b82ea894c 100644
> --- a/arch/loongarch/kernel/ptrace.c
> +++ b/arch/loongarch/kernel/ptrace.c
> @@ -193,7 +193,7 @@ static int fpr_set(struct task_struct *target,
>   		   const void *kbuf, const void __user *ubuf)
>   {
>   	const int fcc_start = NUM_FPU_REGS * sizeof(elf_fpreg_t);
> -	const int fcc_end = fcc_start + sizeof(u64);
> +	const int fcsr_start = fcc_start + sizeof(u64);
>   	int err;
>   
>   	BUG_ON(count % sizeof(elf_fpreg_t));
> @@ -209,10 +209,12 @@ static int fpr_set(struct task_struct *target,
>   	if (err)
>   		return err;
>   
> -	if (count > 0)
> -		err |= user_regset_copyin(&pos, &count, &kbuf, &ubuf,
> -					  &target->thread.fpu.fcc,
> -					  fcc_start, fcc_end);
> +	err |= user_regset_copyin(&pos, &count, &kbuf, &ubuf,
> +				  &target->thread.fpu.fcc, fcc_start,
> +				  fcc_start + sizeof(u64));
> +	err |= user_regset_copyin(&pos, &count, &kbuf, &ubuf,
> +				  &target->thread.fpu.fcsr, fcsr_start,
> +				  fcsr_start + sizeof(u32));
>   
>   	return err;
>   }