linux-kernel - Re: [PATCH 3/4] [mm/nommu]: use copy_to_user_page to call flush icache for [#811] toolchain old bug

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Date:	Thu, 15 May 2008 14:24:12 +0800
From:	"Bryan Wu" <cooloney@...nel.org>
To:	linux-kernel@...r.kernel.org, linux-mm@...ck.org,
	dwmw2@...radead.org
Cc:	"Jie Zhang" <jie.zhang@...log.com>,
	"Bryan Wu" <cooloney@...nel.org>
Subject: Re: [PATCH 3/4] [mm/nommu]: use copy_to_user_page to call flush icache for [#811] toolchain old bug

Is this patch OK for the nommu, David?

Thanks
-Bryan

On Mon, May 12, 2008 at 6:32 PM, Bryan Wu <cooloney@...nel.org> wrote:
> From: Jie Zhang <jie.zhang@...log.com>
>
> access_process_vm in mm/memory.c uses copy_to_user_page and
> copy_from_user_page. So for !MMU we'd better do the same thing.
> Other archs with mmu do the cache flush in copy_to_user_page.
> It gives me hint that copy_to_user_page is designed to flush
> the cache. On other side, no archs do the cache flush ptrace.
>
> Signed-off-by: Jie Zhang <jie.zhang@...log.com>
> Signed-off-by: Bryan Wu <cooloney@...nel.org>
> ---
>  mm/nommu.c |    6 ++++--
>  1 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/mm/nommu.c b/mm/nommu.c
> index c11e5cc..56bb447 100644
> --- a/mm/nommu.c
> +++ b/mm/nommu.c
> @@ -1458,9 +1458,11 @@ 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 {
> --
> 1.5.5
>
>
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