[PATCH v4 21/29] arm64/ptrace: add support for FEAT_POE

[Anshuman Khandual]

On 5/3/24 18:31, Joey Gouly wrote:
> Add a regset for POE containing POR_EL0.
> 
> Signed-off-by: Joey Gouly <joey.gouly at arm.com>
> Cc: Catalin Marinas <catalin.marinas at arm.com>
> Cc: Will Deacon <will at kernel.org>
> Reviewed-by: Mark Brown <broonie at kernel.org>
> Reviewed-by: Catalin Marinas <catalin.marinas at arm.com>

Reviewed-by: Anshuman Khandual <anshuman.khandual at arm.com>

> ---
>  arch/arm64/kernel/ptrace.c | 46 ++++++++++++++++++++++++++++++++++++++
>  include/uapi/linux/elf.h   |  1 +
>  2 files changed, 47 insertions(+)
> 
> diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
> index 0d022599eb61..b756578aeaee 100644
> --- a/arch/arm64/kernel/ptrace.c
> +++ b/arch/arm64/kernel/ptrace.c
> @@ -1440,6 +1440,39 @@ static int tagged_addr_ctrl_set(struct task_struct *target, const struct
>  }
>  #endif
>  
> +#ifdef CONFIG_ARM64_POE
> +static int poe_get(struct task_struct *target,
> +		   const struct user_regset *regset,
> +		   struct membuf to)
> +{
> +	if (!system_supports_poe())
> +		return -EINVAL;
> +
> +	return membuf_write(&to, &target->thread.por_el0,
> +			    sizeof(target->thread.por_el0));
> +}
> +
> +static int poe_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;
> +	long ctrl;
> +
> +	if (!system_supports_poe())
> +		return -EINVAL;
> +
> +	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &ctrl, 0, -1);
> +	if (ret)
> +		return ret;
> +
> +	target->thread.por_el0 = ctrl;
> +
> +	return 0;
> +}
> +#endif
> +
>  enum aarch64_regset {
>  	REGSET_GPR,
>  	REGSET_FPR,
> @@ -1469,6 +1502,9 @@ enum aarch64_regset {
>  #ifdef CONFIG_ARM64_TAGGED_ADDR_ABI
>  	REGSET_TAGGED_ADDR_CTRL,
>  #endif
> +#ifdef CONFIG_ARM64_POE
> +	REGSET_POE
> +#endif
>  };
>  
>  static const struct user_regset aarch64_regsets[] = {
> @@ -1628,6 +1664,16 @@ static const struct user_regset aarch64_regsets[] = {
>  		.set = tagged_addr_ctrl_set,
>  	},
>  #endif
> +#ifdef CONFIG_ARM64_POE
> +	[REGSET_POE] = {
> +		.core_note_type = NT_ARM_POE,
> +		.n = 1,
> +		.size = sizeof(long),
> +		.align = sizeof(long),
> +		.regset_get = poe_get,
> +		.set = poe_set,
> +	},
> +#endif
>  };
>  
>  static const struct user_regset_view user_aarch64_view = {
> diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h
> index b54b313bcf07..81762ff3c99e 100644
> --- a/include/uapi/linux/elf.h
> +++ b/include/uapi/linux/elf.h
> @@ -441,6 +441,7 @@ typedef struct elf64_shdr {
>  #define NT_ARM_ZA	0x40c		/* ARM SME ZA registers */
>  #define NT_ARM_ZT	0x40d		/* ARM SME ZT registers */
>  #define NT_ARM_FPMR	0x40e		/* ARM floating point mode register */
> +#define NT_ARM_POE	0x40f		/* ARM POE registers */
>  #define NT_ARC_V2	0x600		/* ARCv2 accumulator/extra registers */
>  #define NT_VMCOREDD	0x700		/* Vmcore Device Dump Note */
>  #define NT_MIPS_DSP	0x800		/* MIPS DSP ASE registers */