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SubjectRe: [PATCH v12 09/17] riscv: Add ptrace vector support
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On 9/21/22 14:43, Chris Stillson wrote:
> From: Greentime Hu <greentime.hu@sifive.com>
>
> This patch adds ptrace support for riscv vector. The vector registers will
> be saved in datap pointer of __riscv_v_state. This pointer will be set
> right after the __riscv_v_state data structure then it will be put in ubuf
> for ptrace system call to get or set. It will check if the datap got from
> ubuf is set to the correct address or not when the ptrace system call is
> trying to set the vector registers.
>
> Co-developed-by: Vincent Chen <vincent.chen@sifive.com>
> Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
> Signed-off-by: Greentime Hu <greentime.hu@sifive.com>
> ---
> arch/riscv/include/uapi/asm/ptrace.h | 6 +++
> arch/riscv/kernel/ptrace.c | 71 ++++++++++++++++++++++++++++
> include/uapi/linux/elf.h | 1 +
> 3 files changed, 78 insertions(+)
>
> diff --git a/arch/riscv/include/uapi/asm/ptrace.h b/arch/riscv/include/uapi/asm/ptrace.h
> index 6ee1ca2edfa7..2491875be80d 100644
> --- a/arch/riscv/include/uapi/asm/ptrace.h
> +++ b/arch/riscv/include/uapi/asm/ptrace.h
> @@ -94,6 +94,12 @@ struct __riscv_v_state {
> */
> };
>
> +/*
> + * According to spec: The number of bits in a single vector register,
> + * VLEN >= ELEN, which must be a power of 2, and must be no greater than
> + * 2^16 = 65536bits = 8192bytes
> + */
> +#define RISCV_MAX_VLENB (8192)

Need a line here.

> #endif /* __ASSEMBLY__ */
>
> #endif /* _UAPI_ASM_RISCV_PTRACE_H */
> diff --git a/arch/riscv/kernel/ptrace.c b/arch/riscv/kernel/ptrace.c
> index 2ae8280ae475..cce459ff551d 100644
> --- a/arch/riscv/kernel/ptrace.c
> +++ b/arch/riscv/kernel/ptrace.c
> @@ -27,6 +27,9 @@ enum riscv_regset {
> #ifdef CONFIG_FPU
> REGSET_F,
> #endif
> +#ifdef CONFIG_VECTOR
> + REGSET_V,
> +#endif
> };
>
> static int riscv_gpr_get(struct task_struct *target,
> @@ -83,6 +86,64 @@ static int riscv_fpr_set(struct task_struct *target,
> }
> #endif
>
> +#ifdef CONFIG_VECTOR
> +static int riscv_vr_get(struct task_struct *target,
> + const struct user_regset *regset,
> + struct membuf to)
> +{
> + struct __riscv_v_state *vstate = &target->thread.vstate;
> +
> + /*
> + * Ensure the vector registers have been saved to the memory before
> + * copying them to membuf.
> + */
> + if (target == current)
> + vstate_save(current, task_pt_regs(current));
> +
> + /* Copy vector header from vstate. */
> + membuf_write(&to, vstate, RISCV_V_STATE_DATAP);
> + membuf_zero(&to, sizeof(void *));
> +#if __riscv_xlen == 32
> + membuf_zero(&to, sizeof(__u32));
> +#endif
> +
> + /* Copy all the vector registers from vstate. */
> + return membuf_write(&to, vstate->datap, riscv_vsize);
> +}
> +
> +static int riscv_vr_set(struct task_struct *target,
> + const struct user_regset *regset,
> + unsigned int pos, unsigned int count,
> + const void *kbuf, const void __user *ubuf)
> +{
> + int ret, size;
> + struct __riscv_v_state *vstate = &target->thread.vstate;
> +
> + /* Copy rest of the vstate except datap and __padding. */
> + ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, vstate, 0,
> + RISCV_V_STATE_DATAP);
> + if (unlikely(ret))
> + return ret;
> +
> + /* Skip copy datap. */
> + size = sizeof(vstate->datap);
> + count -= size;
> + ubuf += size;
> +#if __riscv_xlen == 32
> + /* Skip copy _padding. */
> + size = sizeof(vstate->__padding);
> + count -= size;
> + ubuf += size;
> +#endif
> +
> + /* Copy all the vector registers. */
> + pos = 0;
> + ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, vstate->datap,
> + 0, riscv_vsize);
> + return ret;
> +}
> +#endif
> +
> static const struct user_regset riscv_user_regset[] = {
> [REGSET_X] = {
> .core_note_type = NT_PRSTATUS,
> @@ -102,6 +163,16 @@ static const struct user_regset riscv_user_regset[] = {
> .set = riscv_fpr_set,
> },
> #endif
> +#ifdef CONFIG_VECTOR
> + [REGSET_V] = {
> + .core_note_type = NT_RISCV_VECTOR,
> + .align = 16,
> + .n = (32 * RISCV_MAX_VLENB)/sizeof(__u32),
> + .size = sizeof(__u32),
> + .regset_get = riscv_vr_get,
> + .set = riscv_vr_set,
> + },
> +#endif
> };
>
> static const struct user_regset_view riscv_user_native_view = {
> diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h
> index c7b056af9ef0..5a5056c6a2a1 100644
> --- a/include/uapi/linux/elf.h
> +++ b/include/uapi/linux/elf.h
> @@ -439,6 +439,7 @@ typedef struct elf64_shdr {
> #define NT_MIPS_DSP 0x800 /* MIPS DSP ASE registers */
> #define NT_MIPS_FP_MODE 0x801 /* MIPS floating-point mode */
> #define NT_MIPS_MSA 0x802 /* MIPS SIMD registers */
> +#define NT_RISCV_VECTOR 0x900 /* RISC-V vector registers */
> #define NT_LOONGARCH_CPUCFG 0xa00 /* LoongArch CPU config registers */
> #define NT_LOONGARCH_CSR 0xa01 /* LoongArch control and status registers */
> #define NT_LOONGARCH_LSX 0xa02 /* LoongArch Loongson SIMD Extension registers */

I think we should break this one out as a seperate patch to be applied
independently, avoid merge conflicts (but this file doesn't change much
anyways. @Arnd or is it ok to carry with riscv change ?

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