diff mbox series

[v12,09/17] riscv: Add ptrace vector support

Message ID 20220921214439.1491510-9-stillson@rivosinc.com (mailing list archive)
State New, archived
Headers show
Series [v12,01/17] riscv: Rename __switch_to_aux -> fpu | expand

Commit Message

Chris Stillson Sept. 21, 2022, 9:43 p.m. UTC 
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(+)

Comments

Vineet Gupta Nov. 8, 2022, 1:38 a.m. UTC | #1 
Trimmed CC list

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 ?
Arnd Bergmann Nov. 14, 2022, 8:01 p.m. UTC | #2 
On Tue, Nov 8, 2022, at 02:38, Vineet Gupta wrote:
>>   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 ?

I only saw this by accident, sorry for not replying earlier. Yes, please
keep it in this patch and merge it through the riscv tree.

       Arnd
diff mbox series

Patch

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)
 #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 */