Re: [PATCH? v2] powerpc: Hard wire PT_SOFTE value to 1 in gpr_get() too

[Madhavan Srinivasan]

On 6/10/20 8:37 PM, Oleg Nesterov wrote:
> Hi,
>
> looks like this patch was forgotten.

yep, I missed this. But mpe did have comments for the patch.

https://lkml.org/lkml/2019/9/19/107

Maddy
> Do you think this should be fixed or should we document that
> PTRACE_GETREGS is not consistent with PTRACE_PEEKUSER on ppc64?
>
>
> On 09/17, Oleg Nesterov wrote:
> > I don't have a ppc machine, this patch wasn't even compile tested,
> > could you please review?
> >
> > 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
> > http://sourceware.org/systemtap/wiki/utrace/tests/user-regs-peekpoke
> >
> > Reported-by: Jan Kratochvil <jan.kratochvil@xxxxxxxxxx>
> > Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
> > ---
> >   arch/powerpc/kernel/ptrace.c | 25 +++++++++++++++++++++++++
> >   1 file changed, 25 insertions(+)
> >
> > diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
> > index 8c92feb..291acfb 100644
> > --- a/arch/powerpc/kernel/ptrace.c
> > +++ b/arch/powerpc/kernel/ptrace.c
> > @@ -363,11 +363,36 @@ static int gpr_get(struct task_struct *target, const struct user_regset *regset,
> >   	BUILD_BUG_ON(offsetof(struct pt_regs, orig_gpr3) !=
> >   		     offsetof(struct pt_regs, msr) + sizeof(long));
> >   
> > +#ifdef CONFIG_PPC64
> > +	if (!ret)
> > +		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> > +					  &target->thread.regs->orig_gpr3,
> > +					  offsetof(struct pt_regs, orig_gpr3),
> > +					  offsetof(struct pt_regs, softe));
> > +
> > +	if (!ret) {
> > +		unsigned long softe = 0x1;
> > +		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &softe,
> > +					  offsetof(struct pt_regs, softe),
> > +					  offsetof(struct pt_regs, softe) +
> > +					  sizeof(softe));
> > +	}
> > +
> > +	BUILD_BUG_ON(offsetof(struct pt_regs, trap) !=
> > +		     offsetof(struct pt_regs, softe) + sizeof(long));
> > +
> > +	if (!ret)
> > +		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> > +					  &target->thread.regs->trap,
> > +					  offsetof(struct pt_regs, trap),
> > +					  sizeof(struct user_pt_regs));
> > +#else
> >   	if (!ret)
> >   		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> >   					  &target->thread.regs->orig_gpr3,
> >   					  offsetof(struct pt_regs, orig_gpr3),
> >   					  sizeof(struct user_pt_regs));
> > +#endif
> >   	if (!ret)
> >   		ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
> >   					       sizeof(struct user_pt_regs), -1);
> > --
> > 2.5.0