As a matter of convention, mainline backports should have exactly the
same shortlog and long log as the original commit with:
commit <foo> upstream
added after the shorlog.
So in this case:
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>
Cheers,
Bruce
On 14-03-18 12:56 AM, Charlie Paul wrote:
From: Jonas Svennebring <jonas.svennebr...@lsi.com>
ARM: 7840/1: LPAE: don't reject mapping /dev/mem above 4GB
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.
Signed-off-by: Jonas Svennebring <jonas.svennebr...@lsi.com>
---
arch/arm/mm/mmap.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c
index f0ef2f7..2db5d2d 100644
--- a/arch/arm/mm/mmap.c
+++ b/arch/arm/mm/mmap.c
@@ -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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