Thread (27 messages) flat view 27 messages, 10 authors, 2011-10-07

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

From: Eric Miao <hidden>
Date: 2011-08-23 00:08:04
Also in: lkml

On Tue, Aug 23, 2011 at 7:47 AM, Andres Salomon [off-list ref] wrote:
quoted hunk ↗ jump to hunk
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 <redacted>
---
?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
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