[PATCH 10/12] ARM: add early malloc support needed by the decompressor

[Jean-Christophe PLAGNIOL-VILLARD]

On 10:30 Mon 30 Jul     , Sascha Hauer wrote:
> On Mon, Jul 30, 2012 at 10:19:42AM +0200, Jean-Christophe PLAGNIOL-VILLARD wrote:
> > On 10:02 Mon 30 Jul     , Sascha Hauer wrote:
> > > On Fri, Jul 27, 2012 at 08:33:08PM +0200, Jean-Christophe PLAGNIOL-VILLARD wrote:
> > > > This is not needed by lzo but by gunzip, xz and others.
> > > > 
> > > > Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
> > > > ---
> > > >  arch/arm/cpu/start.c |    7 +++++++
> > > >  1 file changed, 7 insertions(+)
> > > > 
> > > > diff --git a/arch/arm/cpu/start.c b/arch/arm/cpu/start.c
> > > > index a54f5fd..f500ca8 100644
> > > > --- a/arch/arm/cpu/start.c
> > > > +++ b/arch/arm/cpu/start.c
> > > > @@ -28,6 +28,9 @@
> > > >  #include <asm-generic/memory_layout.h>
> > > >  #include <asm/sections.h>
> > > >  
> > > > +unsigned long free_mem_ptr;
> > > > +unsigned long free_mem_end_ptr;
> > > > +
> > > >  #ifdef CONFIG_PBL_IMAGE
> > > >  void __naked __section(.text_head_entry) pbl_start(void)
> > > >  {
> > > > @@ -193,6 +196,10 @@ void __naked __section(.text_ll_return) board_init_lowlevel_return(void)
> > > >  	/* clear bss */
> > > >  	memset(__bss_start, 0, __bss_stop - __bss_start);
> > > >  
> > > > +	/* set 128 KiB before the STACK_BASE - 16 address for early malloc */
> > > > +	free_mem_ptr = STACK_BASE - 0x20000 - 16;
> > > > +	free_mem_end_ptr = STACK_BASE - 16;
> > > > +
> > > 
> > > This assumes that the malloc area is directly before the stack. How
> > > about using __bss_stop or _end instead?
> > 
> > it's just for early alloc and __bss_stop no so maybe we can use the same as
> > Malloc but we already use this for HEAD_TEXT_BASE
> 
> _end is HEAD_TEXT_BASE + the space needed for the compressed
> image, so what's wrong with it?
the pbl image can be stored in a sram and link to fit there so _end could be
at the end of the sram

so we can not use it.

We need to put the early malloc in the sdram

as example on at91 I plan to load the pbl only without the compressed data

Best Regards,
J.