powerpc/mm: Bring hugepage PTE accessor functions back into sync with normal accessors

The hugepage arch code provides a number of hook functions/macros
which mirror the functionality of various normal page pte access
functions.  Various changes in the normal page accessors (in
particular BenH's recent changes to the handling of lazy icache
flushing and PAGE_EXEC) have caused the hugepage versions to get out
of sync with the originals.  In some cases, this is a bug, at least on
some MMU types.

One of the reasons that some hooks were not identical to the normal
page versions, is that the fact we're dealing with a hugepage needed
to be passed down do use the correct dcache-icache flush function.
This patch makes the main flush_dcache_icache_page() function hugepage
aware (by checking for the PageCompound flag).  That in turn means we
can make set_huge_pte_at() just a call to set_pte_at() bringing it
back into sync.  As a bonus, this lets us remove the
hash_huge_page_do_lazy_icache() function, replacing it with a call to
the hash_page_do_lazy_icache() function it was based on.

Some other hugepage pte access hooks - huge_ptep_get_and_clear() and
huge_ptep_clear_flush() - are not so easily unified, but this patch at
least brings them back into sync with the current versions of the
corresponding normal page functions.

Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 13 insertions, 4 deletions

diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 59736317bf0e..b9b152558f9c 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -32,6 +32,7 @@
 #include <linux/pagemap.h>
 #include <linux/suspend.h>
 #include <linux/lmb.h>
+#include <linux/hugetlb.h>
 
 #include <asm/pgalloc.h>
 #include <asm/prom.h>
@@ -417,18 +418,26 @@ EXPORT_SYMBOL(flush_dcache_page);
 
 void flush_dcache_icache_page(struct page *page)
 {
+#ifdef CONFIG_HUGETLB_PAGE
+	if (PageCompound(page)) {
+		flush_dcache_icache_hugepage(page);
+		return;
+	}
+#endif
 #ifdef CONFIG_BOOKE
-	void *start = kmap_atomic(page, KM_PPC_SYNC_ICACHE);
-	__flush_dcache_icache(start);
-	kunmap_atomic(start, KM_PPC_SYNC_ICACHE);
+	{
+		void *start = kmap_atomic(page, KM_PPC_SYNC_ICACHE);
+		__flush_dcache_icache(start);
+		kunmap_atomic(start, KM_PPC_SYNC_ICACHE);
+	}
 #elif defined(CONFIG_8xx) || defined(CONFIG_PPC64)
 	/* On 8xx there is no need to kmap since highmem is not supported */
 	__flush_dcache_icache(page_address(page)); 
 #else
 	__flush_dcache_icache_phys(page_to_pfn(page) << PAGE_SHIFT);
 #endif
-
 }
+
 void clear_user_page(void *page, unsigned long vaddr, struct page *pg)
 {
 	clear_page(page);