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MIPS: Flush highmem pages in __flush_dcache_page

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When flush_dcache_page is called on an executable page, that page is
about to be provided to userland & we can presume that the icache
contains no valid entries for its address range. However if the icache
does not fill from the dcache then we cannot presume that the pages
content has been written back as far as the memories that the dcache
will fill from (ie. L2 or further out).

This was being done for lowmem pages, but not for highmem which can lead
to icache corruption. Fix this by mapping highmem pages & flushing their
content from the dcache in __flush_dcache_page before providing the page
to userland, just as is done for lowmem pages.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Lars Persson <lars.persson@axis.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/12720/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Paul Burton 2016-03-01 02:37:57 +00:00 committed by Ralf Baechle
parent 763fee97e7
commit 234859e49a
1 changed files with 9 additions and 3 deletions
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12
arch/mips/mm/cache.c
View file

@ -16,6 +16,7 @@
#include <linux/mm.h>
#include <asm/cacheflush.h>
#include <asm/highmem.h>
#include <asm/processor.h>
#include <asm/cpu.h>
#include <asm/cpu-features.h>
@ -83,8 +84,6 @@ void __flush_dcache_page(struct page *page)
struct address_space *mapping = page_mapping(page);
unsigned long addr;
if (PageHighMem(page))
return;
if (mapping && !mapping_mapped(mapping)) {
SetPageDcacheDirty(page);
return;
@ -95,8 +94,15 @@ void __flush_dcache_page(struct page *page)
* case is for exec env/arg pages and those are %99 certainly going to
* get faulted into the tlb (and thus flushed) anyways.
*/
addr = (unsigned long) page_address(page);
if (PageHighMem(page))
addr = (unsigned long)kmap_atomic(page);
else
addr = (unsigned long)page_address(page);
flush_data_cache_page(addr);
if (PageHighMem(page))
__kunmap_atomic((void *)addr);
}
EXPORT_SYMBOL(__flush_dcache_page);