[U-Boot] [PATCH v5 3/7] bootcount: Add function wrappers to handle bootcount increment and error checking

[Lukasz Majewski]

Hi Alex, Stefan,

> On 08.05.2018 08:58, Alex Kiernan wrote:
> 
> <snip>
> 
> >>> +static inline void bootcount_inc(void)
> >>> +{
> >>> +       unsigned long bootcount = bootcount_load();
> >>> +
> >>> +       if (gd->flags & GD_FLG_SPL_INIT) {
> >>> +               bootcount_store(++bootcount);
> >>> +               return;
> >>> +       }
> >>> +
> >>> +#ifndef CONFIG_SPL_BUILD
> >>> +       /* Only increment bootcount when no bootcount support in
> >>> SPL */ +#ifndef CONFIG_SPL_BOOTCOUNT_LIMIT
> >>> +       bootcount_store(++bootcount);
> >>> +#endif
> >>> +       env_set_ulong("bootcount", bootcount);
> >>> +#endif /* !CONFIG_SPL_BUILD */
> >>> +}
> >>> +  
> >   
> >> I'm kinda confused by this code... isn't this equivalent.?  
> >   
> >>       static inline void bootcount_inc(void)
> >>       {
> >>              unsigned long bootcount = bootcount_load();  
> >   
> >>              bootcount_store(++bootcount);
> >>       #ifndef CONFIG_SPL_BUILD
> >>              env_set_ulong("bootcount", bootcount);
> >>       #endif /* !CONFIG_SPL_BUILD */
> >>       }  
> > 
> > I should've included my reasoning as I've got to be missing
> > something... if GD_FLG_SPL_INIT is always set when we get here in
> > SPL, then it's equivalent to the compile time guard. Which I think
> > says I don't understand the flow to how we get here, otherwise we
> > wouldn't need the runtime guard.  
> 
> When using with SPL and bootcounter support, this code will get
> called twice, first from the SPL, where the counter will get
> incremented. And second from main U-Boot, where we need to make
> sure, that the counter does not get incremented again, if SPL
> has already done so.

+1

> 
> With your patch version, the bootcounter would get incremented
> twice in this case.
> 
> Thanks,
> Stefan




Best regards,

Lukasz Majewski

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