ARM: mm: Add support for flushing HugeTLB pages.

On ARM we use the __flush_dcache_page function to flush the dcache
of pages when needed; usually when the PG_dcache_clean bit is unset
and we are setting a PTE.

A HugeTLB page is represented as a compound page consisting of an
array of pages. Thus to flush the dcache of a HugeTLB page, one must
flush more than a single page.

This patch modifies __flush_dcache_page such that all constituent
pages of a HugeTLB page are flushed.

Signed-off-by: Steve Capper <steve.capper@linaro.org>
Reviewed-by: Will Deacon <will.deacon@arm.com>

diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c
index 0d473cc..3706407 100644 (file)
--- a/arch/arm/mm/flush.c
+++ b/arch/arm/mm/flush.c
@@ -17,6 +17,7 @@
 #include <asm/highmem.h>
 #include <asm/smp_plat.h>
 #include <asm/tlbflush.h>
+#include <linux/hugetlb.h>
 
 #include "mm.h"
 
@@ -168,19 +169,23 @@ void __flush_dcache_page(struct address_space *mapping, struct page *page)
         * coherent with the kernels mapping.
         */
        if (!PageHighMem(page)) {
-               __cpuc_flush_dcache_area(page_address(page), PAGE_SIZE);
+               size_t page_size = PAGE_SIZE << compound_order(page);
+               __cpuc_flush_dcache_area(page_address(page), page_size);
        } else {
-               void *addr;
-
+               unsigned long i;
                if (cache_is_vipt_nonaliasing()) {
-                       addr = kmap_atomic(page);
-                       __cpuc_flush_dcache_area(addr, PAGE_SIZE);
-                       kunmap_atomic(addr);
-               } else {
-                       addr = kmap_high_get(page);
-                       if (addr) {
+                       for (i = 0; i < (1 << compound_order(page)); i++) {
+                               void *addr = kmap_atomic(page);
                                __cpuc_flush_dcache_area(addr, PAGE_SIZE);
-                               kunmap_high(page);
+                               kunmap_atomic(addr);
+                       }
+               } else {
+                       for (i = 0; i < (1 << compound_order(page)); i++) {
+                               void *addr = kmap_high_get(page);
+                               if (addr) {
+                                       __cpuc_flush_dcache_area(addr, PAGE_SIZE);
+                                       kunmap_high(page);
+                               }
                        }
                }
        }