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NOMMU: Use copy_*_user_page() in access_process_vm()

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The MMU code uses the copy_*_user_page() variants in access_process_vm()
rather than copy_*_user() as the former includes an icache flush.  This
is important when doing things like setting software breakpoints with
gdb.  So switch the NOMMU code over to do the same.

This patch makes the reasonable assumption that copy_from_user_page()
won't fail - which is probably fine, as we've checked the VMA from which
we're copying is usable, and the copy is not allowed to cross VMAs.  The
one case where it might go wrong is if the VMA is a device rather than
RAM, and that device returns an error which - in which case rubbish will
be returned rather than EIO.

Signed-off-by: Jie Zhang <jie.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: David McCullough <david_mccullough@mcafee.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Acked-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jie Zhang 2010-01-06 17:23:28 +00:00 committed by Linus Torvalds
parent cfe79c00a2
commit 7959722b95
1 changed files with 4 additions and 2 deletions
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6
mm/nommu.c
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@ -1921,9 +1921,11 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, in
/* only read or write mappings where it is permitted */
if (write && vma->vm_flags & VM_MAYWRITE)
len -= copy_to_user((void *) addr, buf, len);
copy_to_user_page(vma, NULL, addr,
(void *) addr, buf, len);
else if (!write && vma->vm_flags & VM_MAYREAD)
len -= copy_from_user(buf, (void *) addr, len);
copy_from_user_page(vma, NULL, addr,
buf, (void *) addr, len);
else
len = 0;
} else {