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Staging: TIDSPBRIDGE: Fix mmap to map the correct region of physical memory

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Commit 559c71fe5d ("Staging: TIDSPBRIDGE: Use vm_iomap_memory for
mmap-ing instead of remap_pfn_range") had the effect of inadvertently
shifting the start of the physical memory area mapped by
pdata->phys_mempool_base.  Correct this by subtracting that shift before
calling vm_iomap_memory() and adding it back afterwards.

Reported-by: Dheeraj CVR <cvr.dheeraj@gmail.com>
Signed-off-by: Ivaylo Dimitrov <freemangordon@abv.bg>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Steven Luo 2013-12-11 22:51:56 +02:00 committed by Greg Kroah-Hartman
parent 76981cf1a1
commit ed75098fd1
1 changed files with 27 additions and 3 deletions
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30
drivers/staging/tidspbridge/rmgr/drv_interface.c
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@ -258,6 +258,8 @@ err:
/* This function maps kernel space memory to user space memory. */
static int bridge_mmap(struct file *filp, struct vm_area_struct *vma)
{
unsigned long base_pgoff;
int status;
struct omap_dsp_platform_data *pdata =
omap_dspbridge_dev->dev.platform_data;
@ -269,9 +271,31 @@ static int bridge_mmap(struct file *filp, struct vm_area_struct *vma)
vma->vm_start, vma->vm_end, vma->vm_page_prot,
vma->vm_flags);
return vm_iomap_memory(vma,
pdata->phys_mempool_base,
pdata->phys_mempool_size);
/*
* vm_iomap_memory() expects vma->vm_pgoff to be expressed as an offset
* from the start of the physical memory pool, but we're called with
* a pfn (physical page number) stored there instead.
*
* To avoid duplicating lots of tricky overflow checking logic,
* temporarily convert vma->vm_pgoff to the offset vm_iomap_memory()
* expects, but restore the original value once the mapping has been
* created.
*/
base_pgoff = pdata->phys_mempool_base >> PAGE_SHIFT;
if (vma->vm_pgoff < base_pgoff)
return -EINVAL;
vma->vm_pgoff -= base_pgoff;
status = vm_iomap_memory(vma,
pdata->phys_mempool_base,
pdata->phys_mempool_size);
/* Restore the original value of vma->vm_pgoff */
vma->vm_pgoff += base_pgoff;
return status;
}
static const struct file_operations bridge_fops = {