Re: [PATCH v3 2/2] powerpc/ptrace: Hard wire PT_SOFTE value to 1 in gpr_get() too

[Christophe Leroy]

Le 19/11/2020 à 17:02, Oleg Nesterov a écrit :
> The commit a8a4b03ab95f ("powerpc: Hard wire PT_SOFTE value to 1 in
> ptrace & signals") changed ptrace_get_reg(PT_SOFTE) to report 0x1,
> but PTRACE_GETREGS still copies pt_regs->softe as is.
>
> This is not consistent and this breaks the user-regs-peekpoke test
> from https://sourceware.org/systemtap/wiki/utrace/tests/
>
> Reported-by: Jan Kratochvil <jan.kratochvil@xxxxxxxxxx>
> Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
> ---
>   arch/powerpc/kernel/ptrace/ptrace-tm.c   | 8 +++++++-
>   arch/powerpc/kernel/ptrace/ptrace-view.c | 8 +++++++-
>   2 files changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/kernel/ptrace/ptrace-tm.c b/arch/powerpc/kernel/ptrace/ptrace-tm.c
> index f8fcbd85d4cb..d0d339f86e61 100644
> --- a/arch/powerpc/kernel/ptrace/ptrace-tm.c
> +++ b/arch/powerpc/kernel/ptrace/ptrace-tm.c
> @@ -87,6 +87,10 @@ int tm_cgpr_get(struct task_struct *target, const struct user_regset *regset,
>   		struct membuf to)
>   {
>   	struct membuf to_msr = membuf_at(&to, offsetof(struct pt_regs, msr));
> +#ifdef CONFIG_PPC64
> +	struct membuf to_softe = membuf_at(&to,
> +					offsetof(struct pt_regs, softe));

Should fit on a single line I think.

> +#endif
>   
>   	if (!cpu_has_feature(CPU_FTR_TM))
>   		return -ENODEV;
> @@ -102,7 +106,9 @@ int tm_cgpr_get(struct task_struct *target, const struct user_regset *regset,
>   				sizeof(struct user_pt_regs));
>   
>   	membuf_store(&to_msr, get_user_ckpt_msr(target));
> -
> +#ifdef CONFIG_PPC64
> +	membuf_store(&to_softe, 0x1ul);
> +#endif
>   	return membuf_zero(&to, ELF_NGREG * sizeof(unsigned long) -
>   				sizeof(struct user_pt_regs));
>   }
> diff --git a/arch/powerpc/kernel/ptrace/ptrace-view.c b/arch/powerpc/kernel/ptrace/ptrace-view.c
> index 39686ede40b3..f554ccfcbfae 100644
> --- a/arch/powerpc/kernel/ptrace/ptrace-view.c
> +++ b/arch/powerpc/kernel/ptrace/ptrace-view.c
> @@ -218,6 +218,10 @@ static int gpr_get(struct task_struct *target, const struct user_regset *regset,
>   		   struct membuf to)
>   {
>   	struct membuf to_msr = membuf_at(&to, offsetof(struct pt_regs, msr));
> +#ifdef CONFIG_PPC64
> +	struct membuf to_softe = membuf_at(&to,
> +					offsetof(struct pt_regs, softe));

Should fit on a single line I think.

> +#endif
>   	int i;
>   
>   	if (target->thread.regs == NULL)
> @@ -233,7 +237,9 @@ static int gpr_get(struct task_struct *target, const struct user_regset *regset,
>   				sizeof(struct user_pt_regs));
>   
>   	membuf_store(&to_msr, get_user_msr(target));
> -
> +#ifdef CONFIG_PPC64
> +	membuf_store(&to_softe, 0x1ul);
> +#endif
>   	return membuf_zero(&to, ELF_NGREG * sizeof(unsigned long) -
>   				sizeof(struct user_pt_regs));
>   }

Christophe