Re: [PATCH v5 07/10] x86/asm/acpi: Fix asmvalidate warnings for wakeup_64.S

Pavel Machek
2015-06-11T12:37:02Z

Hi!

> > > 5. Remove superfluous rsp changes.
> >
> > Did you test the changes?
>
> Yes, I verified that it didn't break suspend/resume on my system.

Ok, so I can not see anything wrong, either. I'd like to understand
why the original code manipulated %rsp, but...

If you did testing with frame pointer on, you can get my

Acked-by: Pavel Machek <pavel@ucw.cz>

> > Do you plan to make similar changes to wakeup_32.S?
>
> Currently, asmvalidate is x86_64 only, so I'm only fixing the 64-bit
> stuff right now.

Well, you are "improving debuggability", afaict. It worked well before.

> > > @@ -108,8 +108,9 @@ ENTRY(do_suspend_lowlevel)
> > > movq pt_regs_r15(%rax), %r15
> > >
> > > xorl %eax, %eax
> > > - addq $8, %rsp
> > > - jmp restore_processor_state
> > > + call restore_processor_state
> > > + FP_RESTORE
> > > + ret
> > > ENDPROC(do_suspend_lowlevel)
> >
> > Umm. I rather liked the direct jump.
>
> Why?

It is both smaller and faster than the new code. But...

Pavel

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