1 files changed, 104 insertions, 0 deletions
diff --git a/include/linux/highmem.h b/include/linux/highmem.h
new file mode 100644
index 000000000000..2a7e6c65c882
--- /dev/null
+++ b/include/linux/highmem.h
@@ -0,0 +1,104 @@
+#ifndef _LINUX_HIGHMEM_H
+#define _LINUX_HIGHMEM_H
+
+#include <linux/config.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+
+#include <asm/cacheflush.h>
+
+#ifdef CONFIG_HIGHMEM
+
+#include <asm/highmem.h>
+
+/* declarations for linux/mm/highmem.c */
+unsigned int nr_free_highpages(void);
+
+#else /* CONFIG_HIGHMEM */
+
+static inline unsigned int nr_free_highpages(void) { return 0; }
+
+static inline void *kmap(struct page *page)
+{
+	might_sleep();
+	return page_address(page);
+}
+
+#define kunmap(page) do { (void) (page); } while (0)
+
+#define kmap_atomic(page, idx)		page_address(page)
+#define kunmap_atomic(addr, idx)	do { } while (0)
+#define kmap_atomic_to_page(ptr)	virt_to_page(ptr)
+
+#endif /* CONFIG_HIGHMEM */
+
+/* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
+static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
+{
+	void *addr = kmap_atomic(page, KM_USER0);
+	clear_user_page(addr, vaddr, page);
+	kunmap_atomic(addr, KM_USER0);
+	/* Make sure this page is cleared on other CPU's too before using it */
+	smp_wmb();
+}
+
+#ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
+static inline struct page *
+alloc_zeroed_user_highpage(struct vm_area_struct *vma, unsigned long vaddr)
+{
+	struct page *page = alloc_page_vma(GFP_HIGHUSER, vma, vaddr);
+
+	if (page)
+		clear_user_highpage(page, vaddr);
+
+	return page;
+}
+#endif
+
+static inline void clear_highpage(struct page *page)
+{
+	void *kaddr = kmap_atomic(page, KM_USER0);
+	clear_page(kaddr);
+	kunmap_atomic(kaddr, KM_USER0);
+}
+
+/*
+ * Same but also flushes aliased cache contents to RAM.
+ */
+static inline void memclear_highpage_flush(struct page *page, unsigned int offset, unsigned int size)
+{
+	void *kaddr;
+
+	BUG_ON(offset + size > PAGE_SIZE);
+
+	kaddr = kmap_atomic(page, KM_USER0);
+	memset((char *)kaddr + offset, 0, size);
+	flush_dcache_page(page);
+	kunmap_atomic(kaddr, KM_USER0);
+}
+
+static inline void copy_user_highpage(struct page *to, struct page *from, unsigned long vaddr)
+{
+	char *vfrom, *vto;
+
+	vfrom = kmap_atomic(from, KM_USER0);
+	vto = kmap_atomic(to, KM_USER1);
+	copy_user_page(vto, vfrom, vaddr, to);
+	kunmap_atomic(vfrom, KM_USER0);
+	kunmap_atomic(vto, KM_USER1);
+	/* Make sure this page is cleared on other CPU's too before using it */
+	smp_wmb();
+}
+
+static inline void copy_highpage(struct page *to, struct page *from)
+{
+	char *vfrom, *vto;
+
+	vfrom = kmap_atomic(from, KM_USER0);
+	vto = kmap_atomic(to, KM_USER1);
+	copy_page(vto, vfrom);
+	kunmap_atomic(vfrom, KM_USER0);
+	kunmap_atomic(vto, KM_USER1);
+}
+
+#endif /* _LINUX_HIGHMEM_H */