[PATCH] bootwrapper: cuboot-83xx: Exclude upper 1MB from heap.

[PATCH] bootwrapper: cuboot-83xx: Exclude upper 1MB from heap.

[Scott Wood]

The uppermost part of memory is where u-boot puts the stack, so don't
include that in the heap.  It's not currently causing problems, as the
current code allocates from the bottom of the heap, but this will keep
things from potentially breaking if a future implementation were to
allocate from the top.

Signed-off-by: Scott Wood <scottwood@freescale.com>
---
 arch/powerpc/boot/cuboot-83xx.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/powerpc/boot/cuboot-83xx.c b/arch/powerpc/boot/cuboot-83xx.c
index 8f11d1e..6cbc20a 100644
--- a/arch/powerpc/boot/cuboot-83xx.c
+++ b/arch/powerpc/boot/cuboot-83xx.c
@@ -61,7 +61,7 @@ void platform_init(unsigned long r3, unsigned long r4, unsigned long r5,
 	loader_info.cmdline = (char *)r6;
 	loader_info.cmdline_len = r7 - r6;
 
-	simple_alloc_init(_end, avail_ram, 32, 64);
+	simple_alloc_init(_end, avail_ram - 1024*1024, 32, 64);
 	ft_init(_dtb_start, _dtb_end - _dtb_start, 32);
 	serial_console_init();
 	platform_ops.fixups = platform_fixups;
-- 
1.5.0.3

Re: [PATCH] bootwrapper: cuboot-83xx: Exclude upper 1MB from heap.

[Kumar Gala]

On Apr 26, 2007, at 12:19 PM, Scott Wood wrote:

> The uppermost part of memory is where u-boot puts the stack, so don't
> include that in the heap.  It's not currently causing problems, as the
> current code allocates from the bottom of the heap, but this will keep
> things from potentially breaking if a future implementation were to
> allocate from the top.

Why does it matter where u-boot puts it stack?  Once control is  
handed over I'd expect it not to matter.

- k

>
> Signed-off-by: Scott Wood <scottwood@freescale.com>
> ---
>  arch/powerpc/boot/cuboot-83xx.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/arch/powerpc/boot/cuboot-83xx.c b/arch/powerpc/boot/ 
> cuboot-83xx.c
> index 8f11d1e..6cbc20a 100644
> --- a/arch/powerpc/boot/cuboot-83xx.c
> +++ b/arch/powerpc/boot/cuboot-83xx.c
> @@ -61,7 +61,7 @@ void platform_init(unsigned long r3, unsigned  
> long r4, unsigned long r5,
>  	loader_info.cmdline = (char *)r6;
>  	loader_info.cmdline_len = r7 - r6;
>
> -	simple_alloc_init(_end, avail_ram, 32, 64);
> +	simple_alloc_init(_end, avail_ram - 1024*1024, 32, 64);
>  	ft_init(_dtb_start, _dtb_end - _dtb_start, 32);
>  	serial_console_init();
>  	platform_ops.fixups = platform_fixups;
> -- 
> 1.5.0.3
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-dev

Re: [PATCH] bootwrapper: cuboot-83xx: Exclude upper 1MB from heap.

[Scott Wood]

Kumar Gala wrote:
> 
> On Apr 26, 2007, at 12:19 PM, Scott Wood wrote:
> 
>> The uppermost part of memory is where u-boot puts the stack, so don't
>> include that in the heap.  It's not currently causing problems, as the
>> current code allocates from the bottom of the heap, but this will keep
>> things from potentially breaking if a future implementation were to
>> allocate from the top.
> 
> 
> Why does it matter where u-boot puts it stack?  Once control is  handed 
> over I'd expect it not to matter.

The bootwrapper uses the stack provided by u-boot (unless the platform 
requests otherwise).

-Scott