1 files changed, 52 insertions, 0 deletions

diff --git a/arch/arm/lib/clear_user.S b/arch/arm/lib/clear_user.S
new file mode 100644
index 000000000000..7ff9f831b3f9
--- /dev/null
+++ b/arch/arm/lib/clear_user.S
@@ -0,0 +1,52 @@
+/*
+ *  linux/arch/arm/lib/clear_user.S
+ *
+ *  Copyright (C) 1995, 1996,1997,1998 Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+
+                .text
+
+/* Prototype: int __arch_clear_user(void *addr, size_t sz)
+ * Purpose  : clear some user memory
+ * Params   : addr - user memory address to clear
+ *          : sz   - number of bytes to clear
+ * Returns  : number of bytes NOT cleared
+ */
+ENTRY(__arch_clear_user)
+                stmfd   sp!, {r1, lr}
+                mov     r2, #0
+                cmp     r1, #4
+                blt     2f
+                ands    ip, r0, #3
+                beq     1f
+                cmp     ip, #2
+USER(           strbt   r2, [r0], #1)
+USER(           strlebt r2, [r0], #1)
+USER(           strltbt r2, [r0], #1)
+                rsb     ip, ip, #4
+                sub     r1, r1, ip              @  7  6  5  4  3  2  1
+1:              subs    r1, r1, #8              @ -1 -2 -3 -4 -5 -6 -7
+USER(           strplt  r2, [r0], #4)
+USER(           strplt  r2, [r0], #4)
+                bpl     1b
+                adds    r1, r1, #4              @  3  2  1  0 -1 -2 -3
+USER(           strplt  r2, [r0], #4)
+2:              tst     r1, #2                  @ 1x 1x 0x 0x 1x 1x 0x
+USER(           strnebt r2, [r0], #1)
+USER(           strnebt r2, [r0], #1)
+                tst     r1, #1                  @ x1 x0 x1 x0 x1 x0 x1
+USER(           strnebt r2, [r0], #1)
+                mov     r0, #0
+                LOADREGS(fd,sp!, {r1, pc})
+
+                .section .fixup,"ax"
+                .align  0
+9001:           LOADREGS(fd,sp!, {r0, pc})
+                .previous
+