Re: [PATCH][6/8] Arch agnostic completely out of line locks / arm

[Zwane Mwaikambo]

On Fri, 3 Sep 2004, Russell King wrote:

> On Thu, Sep 02, 2004 at 08:02:55PM -0400, Zwane Mwaikambo wrote:
> > --- linux-2.6.9-rc1-mm1-stage/arch/arm/kernel/time.c	26 Aug 2004 13:13:04 -0000	1.1.1.1
> > +++ linux-2.6.9-rc1-mm1-stage/arch/arm/kernel/time.c	2 Sep 2004 15:51:37 -0000
> > @@ -52,6 +52,18 @@ EXPORT_SYMBOL(rtc_lock);
> >  /* change this if you have some constant time drift */
> >  #define USECS_PER_JIFFY	(1000000/HZ)
> >
> > +#ifdef CONFIG_SMP
> > +unsigned long profile_pc(struct pt_regs *regs)
> > +{
> > +	unsigned long pc = instruction_pointer(regs);
> > +
> > +	if (pc >= (unsigned long)&__lock_text_start &&
> > +	    pc <= (unsigned long)&__lock_text_end)
> > +		return regs->ARM_lr;
> > +	return pc;
> > +}
> > +EXPORT_SYMBOL(profile_pc);
> > +#endif
>
> Looks good apart from this.  There's no guarantee that LR will be the
> return address inside one of these lock functions - indeed the compiler
> may have saved it onto the stack and decided to use the register for
> something else.
>
> Your best bet is to look at the get_wchan() code which walks the stack
> frames (if present.)

Thanks, i'll change it in the followup.

	Zwane

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