On 2021/7/30 14:49, Liang Wang wrote:
The physical address may exceed 32 bits on ARM(when ARM_LPAE enabled),
use PFN_PHYS() in devmem_is_allowed(), or the physical address may
overflow and be truncated.
This bug was initially introduced from v2.6.37, and the function was moved
to lib when v5.10.
Fixes: 087aaffcdf9c ("ARM: implement CONFIG_STRICT_DEVMEM by disabling access to RAM via /dev/mem")
Fixes: 527701eda5f1 ("lib: Add a generic version of devmem_is_allowed()")
Cc: stable@xxxxxxxxxxxxxxx # v2.6.37
Signed-off-by: Liang Wang <wangliang101@xxxxxxxxxx>
Reviewed-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
---
v2: update subject and changelog
lib/devmem_is_allowed.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/lib/devmem_is_allowed.c b/lib/devmem_is_allowed.c
index c0d67c541849..60be9e24bd57 100644
--- a/lib/devmem_is_allowed.c
+++ b/lib/devmem_is_allowed.c
@@ -19,7 +19,7 @@
*/
int devmem_is_allowed(unsigned long pfn)
{
- if (iomem_is_exclusive(pfn << PAGE_SHIFT))
+ if (iomem_is_exclusive(PFN_PHYS(pfn)))
return 0;
if (!page_is_ram(pfn))
return 1;
