1 files changed, 154 insertions, 0 deletions
diff --git a/arch/sh/lib/clear_page.S b/arch/sh/lib/clear_page.S
new file mode 100644
index 00000000000..3539123fe51
--- /dev/null
+++ b/arch/sh/lib/clear_page.S
@@ -0,0 +1,154 @@
+/*
+ * __clear_user_page, __clear_user, clear_page implementation of SuperH
+ *
+ * Copyright (C) 2001  Kaz Kojima
+ * Copyright (C) 2001, 2002  Niibe Yutaka
+ * Copyright (C) 2006  Paul Mundt
+ */
+#include <linux/linkage.h>
+#include <asm/page.h>
+
+/*
+ * clear_page
+ * @to: P1 address
+ *
+ * void clear_page(void *to)
+ */
+
+/*
+ * r0 --- scratch
+ * r4 --- to
+ * r5 --- to + PAGE_SIZE
+ */
+ENTRY(clear_page)
+	mov	r4,r5
+	mov.l	.Llimit,r0
+	add	r0,r5
+	mov	#0,r0
+	!
+1:
+#if defined(CONFIG_CPU_SH3)
+	mov.l	r0,@r4
+#elif defined(CONFIG_CPU_SH4)
+	movca.l	r0,@r4
+	mov	r4,r1
+#endif
+	add	#32,r4
+	mov.l	r0,@-r4
+	mov.l	r0,@-r4
+	mov.l	r0,@-r4
+	mov.l	r0,@-r4
+	mov.l	r0,@-r4
+	mov.l	r0,@-r4
+	mov.l	r0,@-r4
+#if defined(CONFIG_CPU_SH4)
+	ocbwb	@r1
+#endif
+	cmp/eq	r5,r4
+	bf/s	1b
+	 add	#28,r4
+	!
+	rts
+	 nop
+
+	.balign 4
+.Llimit:	.long	(PAGE_SIZE-28)
+
+ENTRY(__clear_user)
+	!
+	mov	#0, r0
+	mov	#0xe0, r1	! 0xffffffe0
+	!
+	! r4..(r4+31)&~32 	   -------- not aligned	[ Area 0 ]
+	! (r4+31)&~32..(r4+r5)&~32 -------- aligned	[ Area 1 ]
+	! (r4+r5)&~32..r4+r5       -------- not aligned	[ Area 2 ]
+	!
+	! Clear area 0
+	mov	r4, r2
+	!
+	tst	r1, r5		! length < 32
+	bt	.Larea2		! skip to remainder
+	!
+	add	#31, r2
+	and	r1, r2
+	cmp/eq	r4, r2
+	bt	.Larea1
+	mov	r2, r3
+	sub	r4, r3
+	mov	r3, r7
+	mov	r4, r2
+	!
+.L0:	dt	r3
+0:	mov.b	r0, @r2
+	bf/s	.L0
+	 add	#1, r2
+	!
+	sub	r7, r5
+	mov	r2, r4
+.Larea1:
+	mov	r4, r3
+	add	r5, r3
+	and	r1, r3
+	cmp/hi	r2, r3
+	bf	.Larea2
+	!
+	! Clear area 1
+#if defined(CONFIG_CPU_SH4)
+1:	movca.l	r0, @r2
+#else
+1:	mov.l	r0, @r2
+#endif
+	add	#4, r2
+2:	mov.l	r0, @r2
+	add	#4, r2
+3:	mov.l	r0, @r2
+	add	#4, r2
+4:	mov.l	r0, @r2
+	add	#4, r2
+5:	mov.l	r0, @r2
+	add	#4, r2
+6:	mov.l	r0, @r2
+	add	#4, r2
+7:	mov.l	r0, @r2
+	add	#4, r2
+8:	mov.l	r0, @r2
+	add	#4, r2
+	cmp/hi	r2, r3
+	bt/s	1b
+	 nop
+	!
+	! Clear area 2
+.Larea2:
+	mov	r4, r3
+	add	r5, r3
+	cmp/hs	r3, r2
+	bt/s	.Ldone
+	 sub	r2, r3
+.L2:	dt	r3
+9:	mov.b	r0, @r2
+	bf/s	.L2
+	 add	#1, r2
+	!
+.Ldone:	rts
+	 mov	#0, r0	! return 0 as normal return
+
+	! return the number of bytes remained
+.Lbad_clear_user:
+	mov	r4, r0
+	add	r5, r0
+	rts
+	 sub	r2, r0
+
+.section __ex_table,"a"
+	.align 2
+	.long	0b, .Lbad_clear_user
+	.long	1b, .Lbad_clear_user
+	.long	2b, .Lbad_clear_user
+	.long	3b, .Lbad_clear_user
+	.long	4b, .Lbad_clear_user
+	.long	5b, .Lbad_clear_user
+	.long	6b, .Lbad_clear_user
+	.long	7b, .Lbad_clear_user
+	.long	8b, .Lbad_clear_user
+	.long	9b, .Lbad_clear_user
+.previous