| Date | Thu, 17 Jun 2021 10:59:55 +0200 | From | Borislav Petkov <> | Subject | Re: [patch V2 15/52] x86/fpu: Use copy_uabi_xstate_to_membuf() in xfpregs_get() |
| |
On Mon, Jun 14, 2021 at 05:44:23PM +0200, Thomas Gleixner wrote: > Use the new functionality of copy_uabi_xstate_to_membuf() to retrieve the > FX state when XSAVE* is in use. This avoids to overwrite the FPU state
avoids overwriting...
> buffer with fpstate_sanitize_xstate() which is error prone and duplicated > code. > > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > --- > V2: New patch > --- > arch/x86/kernel/fpu/regset.c | 11 ++++++++--- > 1 file changed, 8 insertions(+), 3 deletions(-) > > --- a/arch/x86/kernel/fpu/regset.c > +++ b/arch/x86/kernel/fpu/regset.c > @@ -33,13 +33,18 @@ int xfpregs_get(struct task_struct *targ
So AFAICT, this thing is called by PTRACE_GETFPREGS but looking at ltp:
$ git grep PTRACE_GETFPREGS $
so this is used - if at all used - by some super duper old binaries somewhere.
manpage says "PTRACE_GETREGS and PTRACE_GETFPREGS are not present on all architectures." which could explain why. I wonder if we should add some stupid test cases so that we can at least exercise this...
> struct fpu *fpu = &target->thread.fpu; > > - if (!boot_cpu_has(X86_FEATURE_FXSR)) > + if (!static_cpu_has(X86_FEATURE_FXSR))
cpu_feature_enabled
> return -ENODEV; > > fpu__prepare_read(fpu); > - fpstate_sanitize_xstate(fpu); > > - return membuf_write(&to, &fpu->state.fxsave, sizeof(struct fxregs_state)); > + if (!use_xsave()) { > + return membuf_write(&to, &fpu->state.fxsave, > + sizeof(fpu->state.fxsave)); > + } > + > + copy_uabi_xstate_to_membuf(to, &fpu->state.xsave, XSTATE_COPY_FX); > + return 0;
With the above nitpicks addressed:
Reviewed-by: Borislav Petkov <bp@suse.de>
Thx.
-- Regards/Gruss, Boris.
SUSE Software Solutions Germany GmbH, GF: Felix Imendörffer, HRB 36809, AG Nürnberg
|