powerpc: Merge enough to start building in arch/powerpc.

This creates the directory structure under arch/powerpc and a bunch
of Kconfig files.  It does a first-cut merge of arch/powerpc/mm,
arch/powerpc/lib and arch/powerpc/platforms/powermac.  This is enough
to build a 32-bit powermac kernel with ARCH=powerpc.

For now we are getting some unmerged files from arch/ppc/kernel and
arch/ppc/syslib, or arch/ppc64/kernel.  This makes some minor changes
to files in those directories and files outside arch/powerpc.

The boot directory is still not merged.  That's going to be interesting.

Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/lib/string.S b/arch/powerpc/lib/string.S
new file mode 100644
index 0000000..15d40e9e
--- /dev/null
+++ b/arch/powerpc/lib/string.S
@@ -0,0 +1,203 @@
+/*
+ * String handling functions for PowerPC.
+ *
+ * Copyright (C) 1996 Paul Mackerras.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+#include <linux/config.h>
+#include <asm/processor.h>
+#include <asm/errno.h>
+#include <asm/ppc_asm.h>
+
+	.text
+	.stabs	"arch/powerpc/lib/",N_SO,0,0,0f
+	.stabs	"string.S",N_SO,0,0,0f
+0:
+
+	.section __ex_table,"a"
+#ifdef CONFIG_PPC64
+	.align	3
+#define EXTBL	.llong
+#else
+	.align	2
+#define EXTBL	.long
+#endif
+	.text
+	
+_GLOBAL(strcpy)
+	addi	r5,r3,-1
+	addi	r4,r4,-1
+1:	lbzu	r0,1(r4)
+	cmpwi	0,r0,0
+	stbu	r0,1(r5)
+	bne	1b
+	blr
+
+/* This clears out any unused part of the destination buffer,
+   just as the libc version does.  -- paulus */
+_GLOBAL(strncpy)
+	cmpwi	0,r5,0
+	beqlr
+	mtctr	r5
+	addi	r6,r3,-1
+	addi	r4,r4,-1
+1:	lbzu	r0,1(r4)
+	cmpwi	0,r0,0
+	stbu	r0,1(r6)
+	bdnzf	2,1b		/* dec ctr, branch if ctr != 0 && !cr0.eq */
+	bnelr			/* if we didn't hit a null char, we're done */
+	mfctr	r5
+	cmpwi	0,r5,0		/* any space left in destination buffer? */
+	beqlr			/* we know r0 == 0 here */
+2:	stbu	r0,1(r6)	/* clear it out if so */
+	bdnz	2b
+	blr
+
+_GLOBAL(strcat)
+	addi	r5,r3,-1
+	addi	r4,r4,-1
+1:	lbzu	r0,1(r5)
+	cmpwi	0,r0,0
+	bne	1b
+	addi	r5,r5,-1
+1:	lbzu	r0,1(r4)
+	cmpwi	0,r0,0
+	stbu	r0,1(r5)
+	bne	1b
+	blr
+
+_GLOBAL(strcmp)
+	addi	r5,r3,-1
+	addi	r4,r4,-1
+1:	lbzu	r3,1(r5)
+	cmpwi	1,r3,0
+	lbzu	r0,1(r4)
+	subf.	r3,r0,r3
+	beqlr	1
+	beq	1b
+	blr
+
+_GLOBAL(strlen)
+	addi	r4,r3,-1
+1:	lbzu	r0,1(r4)
+	cmpwi	0,r0,0
+	bne	1b
+	subf	r3,r3,r4
+	blr
+
+_GLOBAL(memcmp)
+	cmpwi	0,r5,0
+	ble-	2f
+	mtctr	r5
+	addi	r6,r3,-1
+	addi	r4,r4,-1
+1:	lbzu	r3,1(r6)
+	lbzu	r0,1(r4)
+	subf.	r3,r0,r3
+	bdnzt	2,1b
+	blr
+2:	li	r3,0
+	blr
+
+_GLOBAL(memchr)
+	cmpwi	0,r5,0
+	ble-	2f
+	mtctr	r5
+	addi	r3,r3,-1
+1:	lbzu	r0,1(r3)
+	cmpw	0,r0,r4
+	bdnzf	2,1b
+	beqlr
+2:	li	r3,0
+	blr
+
+_GLOBAL(__clear_user)
+	addi	r6,r3,-4
+	li	r3,0
+	li	r5,0
+	cmplwi	0,r4,4
+	blt	7f
+	/* clear a single word */
+11:	stwu	r5,4(r6)
+	beqlr
+	/* clear word sized chunks */
+	andi.	r0,r6,3
+	add	r4,r0,r4
+	subf	r6,r0,r6
+	srwi	r0,r4,2
+	andi.	r4,r4,3
+	mtctr	r0
+	bdz	7f
+1:	stwu	r5,4(r6)
+	bdnz	1b
+	/* clear byte sized chunks */
+7:	cmpwi	0,r4,0
+	beqlr
+	mtctr	r4
+	addi	r6,r6,3
+8:	stbu	r5,1(r6)
+	bdnz	8b
+	blr
+90:	mr	r3,r4
+	blr
+91:	mfctr	r3
+	slwi	r3,r3,2
+	add	r3,r3,r4
+	blr
+92:	mfctr	r3
+	blr
+
+	.section __ex_table,"a"
+	EXTBL	11b,90b
+	EXTBL	1b,91b
+	EXTBL	8b,92b
+	.text
+
+_GLOBAL(__strncpy_from_user)
+	addi	r6,r3,-1
+	addi	r4,r4,-1
+	cmpwi	0,r5,0
+	beq	2f
+	mtctr	r5
+1:	lbzu	r0,1(r4)
+	cmpwi	0,r0,0
+	stbu	r0,1(r6)
+	bdnzf	2,1b		/* dec ctr, branch if ctr != 0 && !cr0.eq */
+	beq	3f
+2:	addi	r6,r6,1
+3:	subf	r3,r3,r6
+	blr
+99:	li	r3,-EFAULT
+	blr
+
+	.section __ex_table,"a"
+	EXTBL	1b,99b
+	.text
+
+/* r3 = str, r4 = len (> 0), r5 = top (highest addr) */
+_GLOBAL(__strnlen_user)
+	addi	r7,r3,-1
+	subf	r6,r7,r5	/* top+1 - str */
+	cmplw	0,r4,r6
+	bge	0f
+	mr	r6,r4
+0:	mtctr	r6		/* ctr = min(len, top - str) */
+1:	lbzu	r0,1(r7)	/* get next byte */
+	cmpwi	0,r0,0
+	bdnzf	2,1b		/* loop if --ctr != 0 && byte != 0 */
+	addi	r7,r7,1
+	subf	r3,r3,r7	/* number of bytes we have looked at */
+	beqlr			/* return if we found a 0 byte */
+	cmpw	0,r3,r4		/* did we look at all len bytes? */
+	blt	99f		/* if not, must have hit top */
+	addi	r3,r4,1		/* return len + 1 to indicate no null found */
+	blr
+99:	li	r3,0		/* bad address, return 0 */
+	blr
+
+	.section __ex_table,"a"
+	EXTBL	1b,99b