Re: [PATCH -next v14 11/19] riscv: Add ptrace vector support

Björn Töpel
2023-03-02T11:28:00Z

Andy Chiu <andy.chiu@sifive.com> writes:

> diff --git a/arch/riscv/kernel/ptrace.c b/arch/riscv/kernel/ptrace.c
> index 2ae8280ae475..3c0e01d7f8fb 100644
> --- a/arch/riscv/kernel/ptrace.c
> +++ b/arch/riscv/kernel/ptrace.c
> @@ -83,6 +87,62 @@ static int riscv_fpr_set(struct task_struct *target,
> }
> #endif
>
> +#ifdef CONFIG_RISCV_ISA_V
> +static int riscv_vr_get(struct task_struct *target,
> + const struct user_regset *regset,
> + struct membuf to)
> +{
> + struct __riscv_v_ext_state *vstate = &target->thread.vstate;
> +
> + if (!riscv_v_vstate_query(task_pt_regs(target)))
> + return -EINVAL;
> + /*
> + * Ensure the vector registers have been saved to the memory before
> + * copying them to membuf.
> + */
> + if (target == current)
> + riscv_v_vstate_save(current, task_pt_regs(current));
> +
> + /* Copy vector header from vstate. */
> + membuf_write(&to, vstate, offsetof(struct __riscv_v_ext_state, datap));
> + membuf_zero(&to, sizeof(void *));
> +#if __riscv_xlen == 32
> + membuf_zero(&to, sizeof(__u32));
> +#endif

Remind me why the extra care is needed for 32b?

Björn