From: Franck Bui-Huu <[email protected]>
vma->vm_pgoff is an pfn _offset_ relatif to the begining
of the memory start. The previous code was doing at first:
vma->vm_pgoff << PAGE_SHIFT
which results into a wrong physical address since some
platforms have a physical mem start that can be different
from 0. After that the previous call __pa() on this
wrong physical address, however __pa() is used to convert
a _virtual_ address into a physical one.
This patch rewrites this convertion. It calculates the
pfn of PAGE_OFFSET which is the pfn of the mem start
then it adds the vma->vm_pgoff to it.
It also uses virt_to_phys() instead of __pa() since the
latter shouldn't be used by drivers.
Signed-off-by: Franck Bui-Huu <[email protected]>
---
drivers/char/mem.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 6511012..a89cb52 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -292,8 +292,8 @@ static int mmap_kmem(struct file * file,
{
unsigned long pfn;
- /* Turn a kernel-virtual address into a physical page frame */
- pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT;
+ /* Turn a pfn offset into an absolute pfn */
+ pfn = PFN_DOWN(virt_to_phys((void *)PAGE_OFFSET)) + vma->vm_pgoff;
/*
* RED-PEN: on some architectures there is more mapped memory
--
1.4.2.1.gcd6f1-dirty
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
