1 files changed, 83 insertions, 0 deletions

diff --git a/arch/arm/mm/copypage-v4wb.c b/arch/arm/mm/copypage-v4wb.c
new file mode 100644
index 000000000000..230210822961
--- /dev/null
+++ b/arch/arm/mm/copypage-v4wb.c
@@ -0,0 +1,83 @@
+/*
+ *  linux/arch/arm/mm/copypage-v4wb.c
+ *
+ *  Copyright (C) 1995-1999 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/init.h>
+
+#include <asm/page.h>
+
+/*
+ * ARMv4 optimised copy_user_page
+ *
+ * We flush the destination cache lines just before we write the data into the
+ * corresponding address.  Since the Dcache is read-allocate, this removes the
+ * Dcache aliasing issue.  The writes will be forwarded to the write buffer,
+ * and merged as appropriate.
+ *
+ * Note: We rely on all ARMv4 processors implementing the "invalidate D line"
+ * instruction.  If your processor does not supply this, you have to write your
+ * own copy_user_page that does the right thing.
+ */
+void __attribute__((naked))
+v4wb_copy_user_page(void *kto, const void *kfrom, unsigned long vaddr)
+{
+        asm("\
+        stmfd   sp!, {r4, lr}                   @ 2\n\
+        mov     r2, %0                          @ 1\n\
+        ldmia   r1!, {r3, r4, ip, lr}           @ 4\n\
+1:      mcr     p15, 0, r0, c7, c6, 1           @ 1   invalidate D line\n\
+        stmia   r0!, {r3, r4, ip, lr}           @ 4\n\
+        ldmia   r1!, {r3, r4, ip, lr}           @ 4+1\n\
+        stmia   r0!, {r3, r4, ip, lr}           @ 4\n\
+        ldmia   r1!, {r3, r4, ip, lr}           @ 4\n\
+        mcr     p15, 0, r0, c7, c6, 1           @ 1   invalidate D line\n\
+        stmia   r0!, {r3, r4, ip, lr}           @ 4\n\
+        ldmia   r1!, {r3, r4, ip, lr}           @ 4\n\
+        subs    r2, r2, #1                      @ 1\n\
+        stmia   r0!, {r3, r4, ip, lr}           @ 4\n\
+        ldmneia r1!, {r3, r4, ip, lr}           @ 4\n\
+        bne     1b                              @ 1\n\
+        mcr     p15, 0, r1, c7, c10, 4          @ 1   drain WB\n\
+        ldmfd    sp!, {r4, pc}                  @ 3"
+        :
+        : "I" (PAGE_SIZE / 64));
+}
+
+/*
+ * ARMv4 optimised clear_user_page
+ *
+ * Same story as above.
+ */
+void __attribute__((naked))
+v4wb_clear_user_page(void *kaddr, unsigned long vaddr)
+{
+        asm("\
+        str     lr, [sp, #-4]!\n\
+        mov     r1, %0                          @ 1\n\
+        mov     r2, #0                          @ 1\n\
+        mov     r3, #0                          @ 1\n\
+        mov     ip, #0                          @ 1\n\
+        mov     lr, #0                          @ 1\n\
+1:      mcr     p15, 0, r0, c7, c6, 1           @ 1   invalidate D line\n\
+        stmia   r0!, {r2, r3, ip, lr}           @ 4\n\
+        stmia   r0!, {r2, r3, ip, lr}           @ 4\n\
+        mcr     p15, 0, r0, c7, c6, 1           @ 1   invalidate D line\n\
+        stmia   r0!, {r2, r3, ip, lr}           @ 4\n\
+        stmia   r0!, {r2, r3, ip, lr}           @ 4\n\
+        subs    r1, r1, #1                      @ 1\n\
+        bne     1b                              @ 1\n\
+        mcr     p15, 0, r1, c7, c10, 4          @ 1   drain WB\n\
+        ldr     pc, [sp], #4"
+        :
+        : "I" (PAGE_SIZE / 64));
+}
+
+struct cpu_user_fns v4wb_user_fns __initdata = {
+        .cpu_clear_user_page    = v4wb_clear_user_page,
+        .cpu_copy_user_page     = v4wb_copy_user_page,
+};