On Thu Jan 28, 2021 at 4:38 AM CST, David Laight wrote:
> From: Christopher M. Riedl
> > Sent: 28 January 2021 04:04
> >
> > Reuse the "safe" implementation from signal.c except for calling
> > unsafe_copy_from_user() to copy into a local buffer.
> >
> > Signed-off-by: Christopher M. Riedl <c...@codefail.de>
> > ---
> > arch/powerpc/kernel/signal.h | 33 +++++++++++++++++++++++++++++++++
> > 1 file changed, 33 insertions(+)
> >
> > diff --git a/arch/powerpc/kernel/signal.h b/arch/powerpc/kernel/signal.h
> > index 2559a681536e..c18402d625f1 100644
> > --- a/arch/powerpc/kernel/signal.h
> > +++ b/arch/powerpc/kernel/signal.h
> > @@ -53,6 +53,33 @@ unsigned long copy_ckfpr_from_user(struct task_struct
> > *task, void __user *from);
> > &buf[i], label);\
> > } while (0)
> >
> > +#define unsafe_copy_fpr_from_user(task, from, label) do {
> > \
> > + struct task_struct *__t = task; \
> > + u64 __user *__f = (u64 __user *)from; \
> > + u64 buf[ELF_NFPREG]; \
>
> How big is that buffer?
> Isn't is likely to be reasonably large compared to a reasonable
> kernel stack frame.
> Especially since this isn't even a leaf function.
>
I think Christophe answered this - I don't really have an opinion either
way. What would be a 'reasonable' kernel stack frame for reference?
> > + int i; \
> > + \
> > + unsafe_copy_from_user(buf, __f, ELF_NFPREG * sizeof(double), \
>
> That really ought to be sizeof(buf).
>
Agreed, I will fix this. Thanks!
> David
>
>
> > + label); \
> > + for (i = 0; i < ELF_NFPREG - 1; i++) \
> > + __t->thread.TS_FPR(i) = buf[i]; \
> > + __t->thread.fp_state.fpscr = buf[i]; \
> > +} while (0)
> > +
> > +#define unsafe_copy_vsx_from_user(task, from, label) do {
> > \
> > + struct task_struct *__t = task; \
> > + u64 __user *__f = (u64 __user *)from; \
> > + u64 buf[ELF_NVSRHALFREG]; \
> > + int i; \
> > + \
> > + unsafe_copy_from_user(buf, __f, \
> > + ELF_NVSRHALFREG * sizeof(double), \
> > + label); \
> > + for (i = 0; i < ELF_NVSRHALFREG ; i++) \
> > + __t->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = buf[i]; \
> > +} while (0)
> > +
> > +
> > #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
> > #define unsafe_copy_ckfpr_to_user(to, task, label) do { \
> > struct task_struct *__t = task; \
> > @@ -80,6 +107,10 @@ unsigned long copy_ckfpr_from_user(struct task_struct
> > *task, void __user *from);
> > unsafe_copy_to_user(to, (task)->thread.fp_state.fpr, \
> > ELF_NFPREG * sizeof(double), label)
> >
> > +#define unsafe_copy_fpr_from_user(task, from, label)
> > \
> > + unsafe_copy_from_user((task)->thread.fp_state.fpr, from, \
> > + ELF_NFPREG * sizeof(double), label)
> > +
> > static inline unsigned long
> > copy_fpr_to_user(void __user *to, struct task_struct *task)
> > {
> > @@ -115,6 +146,8 @@ copy_ckfpr_from_user(struct task_struct *task, void
> > __user *from)
> > #else
> > #define unsafe_copy_fpr_to_user(to, task, label) do { } while (0)
> >
> > +#define unsafe_copy_fpr_from_user(task, from, label) do { } while (0)
> > +
> > static inline unsigned long
> > copy_fpr_to_user(void __user *to, struct task_struct *task)
> > {
> > --
> > 2.26.1
>
> -
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