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    SubjectRe: [uClinux-dev] [PATCH] NOMMU: use copy_*_user_page() in access_process_vm()
    Mike Frysinger wrote:
    > From: Jie Zhang <jie.zhang@analog.com>
    >
    > 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.

    Reasonable, but it's a bit subtle don't you think?
    How about a one-line comment saying why it's using copy_*_user_page()?

    (If it was called copy_*_user_flush_icache() I wouldn't say anything,
    but it isn't).

    > Signed-off-by: Jie Zhang <jie.zhang@analog.com>
    > Signed-off-by: Mike Frysinger <vapier@gentoo.org>
    > ---
    > mm/nommu.c | 6 ++++--
    > 1 files changed, 4 insertions(+), 2 deletions(-)
    >
    > diff --git a/mm/nommu.c b/mm/nommu.c
    > index 9876fa0..51ae9be 100644
    > --- a/mm/nommu.c
    > +++ b/mm/nommu.c
    > @@ -1889,9 +1889,11 @@ 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, NULL,
    > + (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, NULL,
    > + buf, (void *) addr, len);
    > else
    > len = 0;
    > } else {


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