[ARM] clearpage: provide our own clear_user_highpage()

For similar reasons as copy_user_page(), we want to avoid the
additional kmap_atomic if it's unnecessary.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 7 insertions, 6 deletions

diff --git a/arch/arm/mm/copypage-v3.c b/arch/arm/mm/copypage-v3.c
index 52df8f04d3f7..13ce0baa6ba5 100644
--- a/arch/arm/mm/copypage-v3.c
+++ b/arch/arm/mm/copypage-v3.c
@@ -54,10 +54,10 @@ void v3_copy_user_highpage(struct page *to, struct page *from,
  *
  * FIXME: do we need to handle cache stuff...
  */
-void __attribute__((naked)) v3_clear_user_page(void *kaddr, unsigned long vaddr)
+void v3_clear_user_highpage(struct page *page, unsigned long vaddr)
 {
+        void *kaddr = kmap_atomic(page, KM_USER0);
         asm("\n\
-        str     lr, [sp, #-4]!\n\
         mov     r1, %1                          @ 1\n\
         mov     r2, #0                          @ 1\n\
         mov     r3, #0                          @ 1\n\
@@ -68,13 +68,14 @@ void __attribute__((naked)) v3_clear_user_page(void *kaddr, unsigned long vaddr)
         stmia   %0!, {r2, r3, ip, lr}           @ 4\n\
         stmia   %0!, {r2, r3, ip, lr}           @ 4\n\
         subs    r1, r1, #1                      @ 1\n\
-        bne     1b                              @ 1\n\
-        ldr     pc, [sp], #4"
+        bne     1b                              @ 1"
         :
-        : "r" (kaddr), "I" (PAGE_SIZE / 64));
+        : "r" (kaddr), "I" (PAGE_SIZE / 64)
+        : "r1", "r2", "r3", "ip", "lr");
+        kunmap_atomic(kaddr, KM_USER0);
 }
 
 struct cpu_user_fns v3_user_fns __initdata = {
-        .cpu_clear_user_page    = v3_clear_user_page,
+        .cpu_clear_user_highpage = v3_clear_user_highpage,
         .cpu_copy_user_highpage = v3_copy_user_highpage,
 };