On Sat, Dec 30, 2006 at 04:39:55PM +0000, Russell King wrote:
> Given that no one has any outstanding issues with the following patch, I'm
> going to ask akpm to put this into -mm, and shortly after (a week or so)
> I'll submit it and the ARM flush_anon_page() patch to Linus for -rc to fix
> ARM data corruption issues.
And here's the flush_anon_page() part.
Add flush_anon_page() for ARM, to avoid data corruption issues when using
fuse or other subsystems using get_user_pages().
Signed-off-by: Russell King <[EMAIL PROTECTED]>
diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c
index 628348c..86dd204 100644
--- a/arch/arm/mm/flush.c
+++ b/arch/arm/mm/flush.c
@@ -202,3 +202,39 @@ #endif
}
}
EXPORT_SYMBOL(flush_dcache_page);
+
+/*
+ * Flush an anonymous page so that users of get_user_pages()
+ * can safely access the data. The expected sequence is:
+ *
+ * get_user_pages()
+ * -> flush_anon_page
+ * memcpy() to/from page
+ * if written to page, flush_dcache_page()
+ */
+void __flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned
long vmaddr)
+{
+ /* VIPT non-aliasing caches need do nothing */
+ if (cache_is_vipt_nonaliasing())
+ return;
+
+ /*
+ * Write back and invalidate userspace mapping.
+ */
+ if (cache_is_vivt()) {
+ flush_cache_page(vma, vmaddr, page_to_pfn(page));
+ } else {
+ /*
+ * For aliasing VIPT, we can flush an alias of the
+ * userspace address only.
+ */
+ flush_pfn_alias(page_to_pfn(page), vmaddr);
+ }
+
+ /*
+ * Invalidate kernel mapping. No data should be contained
+ * in this mapping of the page. FIXME: this is overkill
+ * since we actually ask for a write-back and invalidate.
+ */
+ __cpuc_flush_dcache_page(page_address(page));
+}
diff --git a/include/asm-arm/cacheflush.h b/include/asm-arm/cacheflush.h
index 378a3a2..506ef15 100644
--- a/include/asm-arm/cacheflush.h
+++ b/include/asm-arm/cacheflush.h
@@ -355,6 +355,16 @@ #define clean_dcache_area(start,size) cp
*/
extern void flush_dcache_page(struct page *);
+#define ARCH_HAS_FLUSH_ANON_PAGE
+static inline void flush_anon_page(struct vm_area_struct *vma,
+ struct page *page, unsigned long vmaddr)
+{
+ extern void __flush_anon_page(struct vm_area_struct *vma,
+ struct page *, unsigned long);
+ if (PageAnon(page))
+ __flush_anon_page(vma, page, vmaddr);
+}
+
#define flush_dcache_mmap_lock(mapping) \
write_lock_irq(&(mapping)->tree_lock)
#define flush_dcache_mmap_unlock(mapping) \
--
Russell King
Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
maintainer of:
-
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