Commit 7959722b authored Jan 06, 2010 by Jie Zhang Committed by Linus Torvalds Jan 06, 2010

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



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>

parent cfe79c00

mm/nommu.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -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 {

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