[PATCH] ARM: mmp: map sram as MT_MEMORY rather than MT_DEVICE

Eric Miao
2011-08-23T00:07:41Z

On Tue, Aug 23, 2011 at 7:47 AM, Andres Salomon <dilinger@queued.net> wrote:
> The sram code allocates memory with ioremap, which assumes MT_DEVICE
> for memory protections. ?This explodes when we map sram for power
> management purposes and then attempt to execute it (jump_to_lp_sram)
> on the OLPC XO-1.75. ?Instead, we want to specify MT_MEMORY, which
> doesn't set the L_PTE_XN bit.
>
> Signed-off-by: Andres Salomon <dilinger@queued.net>
> ---
> ?arch/arm/mach-mmp/sram.c | ? ?4 +++-
> ?1 files changed, 3 insertions(+), 1 deletions(-)
>
> Eric, this patch is against the devel branch of your pxa tree.
>
> diff --git a/arch/arm/mach-mmp/sram.c b/arch/arm/mach-mmp/sram.c
> index 4304f95..ca4d3c1 100644
> --- a/arch/arm/mach-mmp/sram.c
> +++ b/arch/arm/mach-mmp/sram.c
> @@ -21,6 +21,7 @@
> ?#include <linux/err.h>
> ?#include <linux/slab.h>
> ?#include <linux/genalloc.h>
> +#include <asm/mach/map.h>
>
> ?#include <mach/sram.h>
>
> @@ -87,7 +88,8 @@ static int __devinit sram_probe(struct platform_device *pdev)
>
> ? ? ? ?info->sram_phys ? = (phys_addr_t)res->start;
> ? ? ? ?info->sram_size ? = resource_size(res);
> - ? ? ? info->sram_virt ? = ioremap(info->sram_phys, info->sram_size);
> + ? ? ? info->sram_virt ? = __arm_ioremap(info->sram_phys, info->sram_size,
> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? MT_MEMORY);

I doubt MT_MEMORY is intended for use with __arm_ioremap(). There could
be other way around to the L_PTE_XN bit.

One other way I'm actually thinking of is to add the SRAM mapping to
mmp_map_io(). The difference of SRAM offset/size may result the
separation of mmp_map_io() into {pxa168,pxa910,mmp2}_map_io()
if necessary.

> ? ? ? ?info->pool_name ? = kstrdup(pdata->pool_name, GFP_KERNEL);
> ? ? ? ?info->granularity = pdata->granularity;
>
> --
> 1.7.2.5
>
>