On Wed, Jun 8, 2011 at 6:19 PM, Greg Ungerer [off-list ref] wrote:

Hi Bob,

On 08/06/11 17:18, Bob Liu wrote:

quoted

Hi, Greg

On Wed, Jun 8, 2011 at 12:47 PM, Greg Ungerer[off-list ref]  wrote:

quoted

Hi Bob,

On 07/06/11 16:19, Bob Liu wrote:

quoted

On Fri, Jun 3, 2011 at 2:37 PM, Greg Ungerer[off-list ref]
 Ã¡wrote:

quoted

Hi Bob,

On 06/05/11 16:03, Bob Liu wrote:

quoted

Currently on nommu arch mmap(),mremap() and munmap() doesn't do
page_align()
which isn't consist with mmu arch and cause some issues.

First, some drivers' mmap() function depends on vma->vm_end -
vma->start
is
page aligned which is true on mmu arch but not on nommu. eg: uvc
camera
driver.

Second munmap() may return -EINVAL[split file] error in cases when end
is
not
page aligned(passed into from userspace) but vma->vm_end is aligned
dure
to
split or driver's mmap() ops.

This patch add page align to fix those issues.

This is actually causing me problems on head at the moment.
git bisected to this patch as the cause.

When booting on a ColdFire (m68knommu) target the init process (or
there abouts at least) fails. Last console messages are:

á...
áVFS: Mounted root (romfs filesystem) readonly on device 31:0.
áFreeing unused kernel memory: 52k freed (0x401aa000 - 0x401b6000)
áUnable to mmap process text, errno 22

Oh, bad news. I will try to reproduce it on my board.
If you are free please enable debug in nommu.c and then we can see what
caused the problem.

Yep, with debug on:

á...
áVFS: Mounted root (romfs filesystem) readonly on device 31:0.
áFreeing unused kernel memory: 52k freed (0x4018c000 - 0x40198000)
á==>  do_mmap_pgoff(,0,6780,5,1002,0)
á<== do_mmap_pgoff() = -22
áUnable to mmap process text, errno 22

Since I can't reproduce this problem, could you please attach the
whole dmesg log with nommu debug on or
you can step into to see why errno 22 is returned, is it returned by
do_mmap_private()?

There was no other debug messages with debug turned on in nommu.c.
(I can give you the boot msgs before this if you want, but there
was no nommu.c debug in it).

But I did trace it into do_mmap_pgoff() to see what was failing.
It fails based on the return value from:

         addr = file->f_op->get_unmapped_area(file, addr, len,
                                                     pgoff, flags);

Thanks for this information.
But it's a callback function. I still can't know what's the problem maybe.
Would you do me a favor to do more trace to see where it callback to,
fs or some driver etc..?

Theres only one call of this inside do_mmap_pgoff() so you its
easy to find.

Regards
Greg

quoted

quoted

I can confirm that the PAGE_ALIGN(len) change in do_mmap_pgoff()
is enough to cause this too.

Regards
Greg

quoted

quoted

I haven't really debugged it any further yet. But that error message
comes from fs/binfmt_flat.c, it is reporting a failed do_mmap() call.

Reverting that this patch and no more problem.

Regards
Greg

-- 
Regards,
--Bob

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