[PATCH 8/9] arm: Add RAMOOPS memory area

[Sascha Hauer]

On Fri, Dec 04, 2015 at 02:30:34PM +0100, Markus Pargmann wrote:
> Hi,
> 
> On Friday 04 December 2015 08:07:40 Sascha Hauer wrote:
> > On Wed, Dec 02, 2015 at 02:48:50PM +0100, Markus Pargmann wrote:
> > > RAMOOPS is a driver that uses a reserved static memory region to store
> > > the data from the last panic or boot. This helps to debug crashes at the
> > > next boot while preserving the boot messages.
> > > 
> > > To guarantee a memory area that is not altered by barebox or the kernel,
> > > this area is located at the end of the RAM right after barebox and
> > > before the STACK. This ensures that changing barebox sizes do not
> > > interfere with RAMOOPS.
> > > 
> > > Signed-off-by: Markus Pargmann <mpa at pengutronix.de>
> > > ---
> > >  arch/arm/cpu/start.c               |  6 ++++++
> > >  arch/arm/include/asm/barebox-arm.h | 14 +++++++++++++-
> > >  2 files changed, 19 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/arch/arm/cpu/start.c b/arch/arm/cpu/start.c
> > > index 4ad64b61e86a..d03d1edfaf18 100644
> > > --- a/arch/arm/cpu/start.c
> > > +++ b/arch/arm/cpu/start.c
> > > @@ -118,6 +118,12 @@ static inline unsigned long arm_mem_boarddata(unsigned long membase,
> > >  	return mem;
> > >  }
> > >  
> > > +unsigned long arm_mem_ramoops_get(void)
> > > +{
> > > +	return arm_mem_ramoops(0, arm_stack_top);
> > > +}
> > > +EXPORT_SYMBOL_GPL(arm_mem_ramoops_get);
> > > +
> > >  static int barebox_memory_areas_init(void)
> > >  {
> > >  	unsigned long start = arm_head_bottom;
> > > diff --git a/arch/arm/include/asm/barebox-arm.h b/arch/arm/include/asm/barebox-arm.h
> > > index da7717538b61..91f1747d2df4 100644
> > > --- a/arch/arm/include/asm/barebox-arm.h
> > > +++ b/arch/arm/include/asm/barebox-arm.h
> > > @@ -122,11 +122,23 @@ static inline unsigned long arm_mem_early_malloc_end(unsigned long membase,
> > >  	return arm_mem_ttb(membase, endmem);
> > >  }
> > >  
> > > +static inline unsigned long arm_mem_ramoops(unsigned long membase,
> > > +					    unsigned long endmem)
> > > +{
> > > +	endmem = arm_mem_ttb(membase, endmem);
> > > +#ifdef CONFIG_FS_PSTORE_RAMOOPS
> > > +	endmem -= CONFIG_FS_PSTORE_RAMOOPS_SIZE;
> > > +	endmem &= ~(SZ_4K - 1); /* Align to 4K */
> > > +#endif
> > 
> > if (IS_ENABLED(CONFIG_FS_PSTORE_RAMOOPS)) please
> 
> This doesn't work here. If CONFIG_FS_PSTORE_RAMOOPS is not defined,
> CONFIG_FS_PSTORE_RAMOOPS_SIZE is undefined as well and compiling fails.
> 
> Is there any macro I should use for _SIZE here or any Kconfig setup that is
> preferred for this situation?

Not that I know of. Just keep it as it is now.

Sascha

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