If you recall, I commented on the format of the upstream backported
fixes and the commit header format .. this one appears to have the
same issues as before.

Bruce

On 2014-04-11, 5:13 PM, Charlie Paul wrote:
From: Jonas Svennebring <jonas.svennebr...@lsi.com>

      ARM: 7840/1: LPAE: don't reject mapping /dev/mem above 4GB

      commit 3159f372354e8e1f5dee714663d70 upstream

      With LPAE enabled, physical address space is larger than 4GB. Allow 
mapping any
      part of it via /dev/mem by using PHYS_MASK to determine valid range.

      PHYS_MASK covers 40 bits with LPAE enabled and 32 bits otherwise.

      Reported-by: Vassili Karpov <av1...@comtv.ru>
      Signed-off-by: Sergey Dyasly <dse...@gmail.com>
      Acked-by: Catalin Marinas <catalin.mari...@arm.com>
      Signed-off-by: Russell King <rmk+ker...@arm.linux.org.uk>
      Signed-off-by: Jonas Svennebring <jonas.svennebr...@lsi.com>
---
  arch/arm/mm/mmap.c |   10 ++++------
  1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c
index f0ef2f7..18d6aeb 100644
--- a/arch/arm/mm/mmap.c
+++ b/arch/arm/mm/mmap.c
@@ -11,7 +11,7 @@
  #include <linux/random.h>
  #include <asm/cachetype.h>

-#define COLOUR_ALIGN(addr,pgoff)               \
+#define COLOUR_ALIGN(addr, pgoff)              \
        ((((addr)+SHMLBA-1)&~(SHMLBA-1)) +  \
         (((pgoff)<<PAGE_SHIFT) & (SHMLBA-1)))

@@ -146,7 +146,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const 
unsigned long addr0,

        info.flags = VM_UNMAPPED_AREA_TOPDOWN;
        info.length = len;
-       info.low_limit = FIRST_USER_ADDRESS;
+       info.low_limit = PAGE_SIZE;
        info.high_limit = mm->mmap_base;
        info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
        info.align_offset = pgoff << PAGE_SHIFT;
@@ -204,13 +204,11 @@ int valid_phys_addr_range(phys_addr_t addr, size_t size)
  }

  /*
- * We don't use supersection mappings for mmap() on /dev/mem, which
- * means that we can't map the memory area above the 4G barrier into
- * userspace.
+ * Do not allow /dev/mem mappings beyond the supported physical range.
   */
  int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
  {
-       return !(pfn + (size >> PAGE_SHIFT) > 0x00100000);
+       return (pfn + (size >> PAGE_SHIFT)) <= (1 + (PHYS_MASK >> PAGE_SHIFT));
  }

  #ifdef CONFIG_STRICT_DEVMEM


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