On Tue, Mar 01, 2016 at 02:37:58AM +0000, Paul Burton wrote:
> The following patch will expose __update_cache to highmem pages. Handle
> them by mapping them in for the duration of the cache maintenance, just
> like in __flush_dcache_page. The code for that isn't shared because we
> need the page address in __update_cache so sharing became messy. Given
> that the entirity is an extra 5 lines, just duplicate it.
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxxxx>
> Cc: Lars Persson <lars.persson@xxxxxxxx>
> Cc: stable <stable@xxxxxxxxxxxxxxx> # v4.1+
> ---
>
> arch/mips/mm/cache.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/arch/mips/mm/cache.c b/arch/mips/mm/cache.c
> index 5a67d8c..8befa55 100644
> --- a/arch/mips/mm/cache.c
> +++ b/arch/mips/mm/cache.c
> @@ -149,9 +149,17 @@ void __update_cache(struct vm_area_struct *vma, unsigned long address,
> return;
> page = pfn_to_page(pfn);
> if (page_mapping(page) && Page_dcache_dirty(page)) {
> - addr = (unsigned long) page_address(page);
> + if (PageHighMem(page))
> + addr = (unsigned long)kmap_atomic(page);
> + else
> + addr = (unsigned long)page_address(page);
> +
> if (exec || pages_do_alias(addr, address & PAGE_MASK))
> flush_data_cache_page(addr);
> +
> + if (PageHighMem(page))
> + __kunmap_atomic((void *)addr);
> +
> ClearPageDcacheDirty(page);
> }
> }
Yet again this is betting the house on getting the right virtual address
from kmap_atomic.
Ralf
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