arm: Update mem* functions to newer versions

The memcpy/memset/memmove assembly implementations have been taken from
U-Boot, which originally got them from Linux. I turns out that they are
actually not that bad, but they could use an update. This patch pulls in
the current Linux upstream versions of those files, removing some old
U-Boot cruft such as checking whether the two pointers in a memcpy() are
equal (really now?) or side-stepping the R8 register because it was used
for special purposes. It also returns to the good old Linux
ENTRY/ENDPROC macros since we have them now anyway, and straightens out
the W() macro in preparation for unified thumb support.

Change-Id: I138af269b423bef0a237759ac29f1ee58ca206a0
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/182179
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
(cherry picked from commit 777127997bde5785b21d422d0b6eb04c4328b478)
Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com>
Reviewed-on: http://review.coreboot.org/6918
Tested-by: build bot (Jenkins)
Reviewed-by: David Hendricks <dhendrix@chromium.org>

6 files changed, 279 insertions, 74 deletions

diff --git a/payloads/libpayload/arch/arm/Makefile.inc b/payloads/libpayload/arch/arm/Makefile.inc
index 8d7bb5e2f8..53a52df6aa 100644
--- a/payloads/libpayload/arch/arm/Makefile.inc
+++ b/payloads/libpayload/arch/arm/Makefile.inc
@@ -33,7 +33,7 @@ head.o-y += head.S
 libc-y += main.c sysinfo.c
 libc-y += timer.c coreboot.c util.S
 libc-y += virtual.c
-libc-y += memcpy.S memset.S
+libc-y += memcpy.S memset.S memmove.S
 libc-y += exception_asm.S exception.c
 libc-y += cache.c
 libcbfs-$(CONFIG_LP_CBFS) += dummy_media.c
diff --git a/payloads/libpayload/arch/arm/assembler.h b/payloads/libpayload/arch/arm/asmlib.h
index 5e4789b145..8b3fa22cc2 100644
--- a/payloads/libpayload/arch/arm/assembler.h
+++ b/payloads/libpayload/arch/arm/asmlib.h
@@ -1,5 +1,7 @@
 /*
- *  arch/arm/include/asm/assembler.h
+ *  arch/arm/asmlib.h
+ *
+ *  Adapted from Linux arch/arm/include/assembler.h
  *
  *  Copyright (C) 1996-2000 Russell King
  *
@@ -15,6 +17,16 @@
  */
 
 /*
+ * WARNING: This file is *only* meant for memcpy.S and friends which were copied
+ * from Linux and require some weird macros. It does unspeakable things like
+ * redefining "push", so do *not* try to turn it into a general assembly macro
+ * file, and keep it out of global include directories.
+ */
+
+#ifndef __ARM_ASMLIB_H__
+#define __ARM_ASMLIB_H__
+
+/*
  * Endian independent macros for shifting bytes within registers.
  */
 #ifndef __ARMEB__
@@ -44,17 +56,17 @@
 /*
  * Data preload for architectures that support it
  */
-#if defined(__ARM_ARCH_5E__) || defined(__ARM_ARCH_5TE__) || \
-	defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || \
-	defined(__ARM_ARCH_6T2__) || defined(__ARM_ARCH_6Z__) || \
-	defined(__ARM_ARCH_6ZK__) || defined(__ARM_ARCH_7A__) || \
-	defined(__ARM_ARCH_7R__)
+#if 1	/* TODO: differentiate once libpayload supports more ARM versions */
 #define PLD(code...)	code
 #else
 #define PLD(code...)
 #endif
 
 /*
- * Cache alligned
+ * This can be used to enable code to cacheline align the destination
+ * pointer when bulk writing to memory. Linux doesn't enable this except
+ * for the "Feroceon" processor, so we better just leave it out.
  */
-#define CALGN(code...) code
+#define CALGN(code...)
+
+#endif	/* __ARM_ASMLIB_H */
diff --git a/payloads/libpayload/arch/arm/memcpy.S b/payloads/libpayload/arch/arm/memcpy.S
index e68b28f542..b8f857bb56 100644
--- a/payloads/libpayload/arch/arm/memcpy.S
+++ b/payloads/libpayload/arch/arm/memcpy.S
@@ -10,9 +10,8 @@
  *  published by the Free Software Foundation.
  */
 
-#include "assembler.h"
-
-#define W(instr)	instr
+#include <arch/asm.h>
+#include "asmlib.h"
 
 #define LDR1W_SHIFT	0
 #define STR1W_SHIFT	0
@@ -57,12 +56,7 @@
 
 /* Prototype: void *memcpy(void *dest, const void *src, size_t n); */
 
-.type memcpy, function
-.globl memcpy
-memcpy:
-
-		cmp	r0, r1
-		moveq	pc, lr
+ENTRY(memcpy)
 
 		enter	r4, lr
 
@@ -242,3 +236,4 @@ memcpy:
 17:		forward_copy_shift	pull=16	push=16
 
 18:		forward_copy_shift	pull=24	push=8
+ENDPROC(memcpy)
diff --git a/payloads/libpayload/arch/arm/memmove.S b/payloads/libpayload/arch/arm/memmove.S
new file mode 100644
index 0000000000..dc29f7458c
--- /dev/null
+++ b/payloads/libpayload/arch/arm/memmove.S
@@ -0,0 +1,199 @@
+/*
+ *  linux/arch/arm/lib/memmove.S
+ *
+ *  Author:	Nicolas Pitre
+ *  Created:	Sep 28, 2005
+ *  Copyright:	(C) MontaVista Software Inc.
+ *
+ *  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 <arch/asm.h>
+#include "asmlib.h"
+
+		.text
+
+/*
+ * Prototype: void *memmove(void *dest, const void *src, size_t n);
+ *
+ * Note:
+ *
+ * If the memory regions don't overlap, we simply branch to memcpy which is
+ * normally a bit faster. Otherwise the copy is done going downwards.  This
+ * is a transposition of the code from copy_template.S but with the copy
+ * occurring in the opposite direction.
+ */
+
+ENTRY(memmove)
+
+		subs	ip, r0, r1
+		cmphi	r2, ip
+		bls	memcpy
+
+		stmfd	sp!, {r0, r4, lr}
+		add	r1, r1, r2
+		add	r0, r0, r2
+		subs	r2, r2, #4
+		blt	8f
+		ands	ip, r0, #3
+	PLD(	pld	[r1, #-4]		)
+		bne	9f
+		ands	ip, r1, #3
+		bne	10f
+
+1:		subs	r2, r2, #(28)
+		stmfd	sp!, {r5 - r8}
+		blt	5f
+
+	CALGN(	ands	ip, r0, #31		)
+	CALGN(	sbcnes	r4, ip, r2		)  @ C is always set here
+	CALGN(	bcs	2f			)
+	CALGN(	adr	r4, 6f			)
+	CALGN(	subs	r2, r2, ip		)  @ C is set here
+	CALGN(	rsb	ip, ip, #32		)
+	CALGN(	add	pc, r4, ip		)
+
+	PLD(	pld	[r1, #-4]		)
+2:	PLD(	subs	r2, r2, #96		)
+	PLD(	pld	[r1, #-32]		)
+	PLD(	blt	4f			)
+	PLD(	pld	[r1, #-64]		)
+	PLD(	pld	[r1, #-96]		)
+
+3:	PLD(	pld	[r1, #-128]		)
+4:		ldmdb	r1!, {r3, r4, r5, r6, r7, r8, ip, lr}
+		subs	r2, r2, #32
+		stmdb	r0!, {r3, r4, r5, r6, r7, r8, ip, lr}
+		bge	3b
+	PLD(	cmn	r2, #96			)
+	PLD(	bge	4b			)
+
+5:		ands	ip, r2, #28
+		rsb	ip, ip, #32
+		addne	pc, pc, ip		@ C is always clear here
+		b	7f
+6:		W(nop)
+		W(ldr)	r3, [r1, #-4]!
+		W(ldr)	r4, [r1, #-4]!
+		W(ldr)	r5, [r1, #-4]!
+		W(ldr)	r6, [r1, #-4]!
+		W(ldr)	r7, [r1, #-4]!
+		W(ldr)	r8, [r1, #-4]!
+		W(ldr)	lr, [r1, #-4]!
+
+		add	pc, pc, ip
+		nop
+		W(nop)
+		W(str)	r3, [r0, #-4]!
+		W(str)	r4, [r0, #-4]!
+		W(str)	r5, [r0, #-4]!
+		W(str)	r6, [r0, #-4]!
+		W(str)	r7, [r0, #-4]!
+		W(str)	r8, [r0, #-4]!
+		W(str)	lr, [r0, #-4]!
+
+	CALGN(	bcs	2b			)
+
+7:		ldmfd	sp!, {r5 - r8}
+
+8:		movs	r2, r2, lsl #31
+		ldrneb	r3, [r1, #-1]!
+		ldrcsb	r4, [r1, #-1]!
+		ldrcsb	ip, [r1, #-1]
+		strneb	r3, [r0, #-1]!
+		strcsb	r4, [r0, #-1]!
+		strcsb	ip, [r0, #-1]
+		ldmfd	sp!, {r0, r4, pc}
+
+9:		cmp	ip, #2
+		ldrgtb	r3, [r1, #-1]!
+		ldrgeb	r4, [r1, #-1]!
+		ldrb	lr, [r1, #-1]!
+		strgtb	r3, [r0, #-1]!
+		strgeb	r4, [r0, #-1]!
+		subs	r2, r2, ip
+		strb	lr, [r0, #-1]!
+		blt	8b
+		ands	ip, r1, #3
+		beq	1b
+
+10:		bic	r1, r1, #3
+		cmp	ip, #2
+		ldr	r3, [r1, #0]
+		beq	17f
+		blt	18f
+
+
+		.macro	backward_copy_shift push pull
+
+		subs	r2, r2, #28
+		blt	14f
+
+	CALGN(	ands	ip, r0, #31		)
+	CALGN(	sbcnes	r4, ip, r2		)  @ C is always set here
+	CALGN(	subcc	r2, r2, ip		)
+	CALGN(	bcc	15f			)
+
+11:		stmfd	sp!, {r5 - r9}
+
+	PLD(	pld	[r1, #-4]		)
+	PLD(	subs	r2, r2, #96		)
+	PLD(	pld	[r1, #-32]		)
+	PLD(	blt	13f			)
+	PLD(	pld	[r1, #-64]		)
+	PLD(	pld	[r1, #-96]		)
+
+12:	PLD(	pld	[r1, #-128]		)
+13:		ldmdb   r1!, {r7, r8, r9, ip}
+		mov     lr, r3, push #\push
+		subs    r2, r2, #32
+		ldmdb   r1!, {r3, r4, r5, r6}
+		orr     lr, lr, ip, pull #\pull
+		mov     ip, ip, push #\push
+		orr     ip, ip, r9, pull #\pull
+		mov     r9, r9, push #\push
+		orr     r9, r9, r8, pull #\pull
+		mov     r8, r8, push #\push
+		orr     r8, r8, r7, pull #\pull
+		mov     r7, r7, push #\push
+		orr     r7, r7, r6, pull #\pull
+		mov     r6, r6, push #\push
+		orr     r6, r6, r5, pull #\pull
+		mov     r5, r5, push #\push
+		orr     r5, r5, r4, pull #\pull
+		mov     r4, r4, push #\push
+		orr     r4, r4, r3, pull #\pull
+		stmdb   r0!, {r4 - r9, ip, lr}
+		bge	12b
+	PLD(	cmn	r2, #96			)
+	PLD(	bge	13b			)
+
+		ldmfd	sp!, {r5 - r9}
+
+14:		ands	ip, r2, #28
+		beq	16f
+
+15:		mov     lr, r3, push #\push
+		ldr	r3, [r1, #-4]!
+		subs	ip, ip, #4
+		orr	lr, lr, r3, pull #\pull
+		str	lr, [r0, #-4]!
+		bgt	15b
+	CALGN(	cmp	r2, #0			)
+	CALGN(	bge	11b			)
+
+16:		add	r1, r1, #(\pull / 8)
+		b	8b
+
+		.endm
+
+
+		backward_copy_shift	push=8	pull=24
+
+17:		backward_copy_shift	push=16	pull=16
+
+18:		backward_copy_shift	push=24	pull=8
+
+ENDPROC(memmove)
diff --git a/payloads/libpayload/arch/arm/memset.S b/payloads/libpayload/arch/arm/memset.S
index aa4f57a993..945767c599 100644
--- a/payloads/libpayload/arch/arm/memset.S
+++ b/payloads/libpayload/arch/arm/memset.S
@@ -9,33 +9,21 @@
  *
  *  ASM optimised string functions
  */
-#include "assembler.h"
+
+#include <arch/asm.h>
+#include "asmlib.h"
 
 	.text
 	.align	5
-	.word	0
 
-1:	subs	r2, r2, #4		@ 1 do we have enough
-	blt	5f			@ 1 bytes to align with?
-	cmp	r3, #2			@ 1
-	strltb	r1, [r0], #1		@ 1
-	strleb	r1, [r0], #1		@ 1
-	strb	r1, [r0], #1		@ 1
-	add	r2, r2, r3		@ 1 (r2 = r2 - (4 - r3))
-/*
- * The pointer is now aligned and the length is adjusted.  Try doing the
- * memset again.
- */
-
-.type memset, function
-.globl memset
-memset:
+ENTRY(memset)
 	ands	r3, r0, #3		@ 1 unaligned?
-	bne	1b			@ 1
+	mov	ip, r0			@ preserve r0 as return value
+	bne	6f			@ 1
 /*
- * we know that the pointer in r0 is aligned to a word boundary.
+ * we know that the pointer in ip is aligned to a word boundary.
  */
-	orr	r1, r1, r1, lsl #8
+1:	orr	r1, r1, r1, lsl #8
 	orr	r1, r1, r1, lsl #16
 	mov	r3, r1
 	cmp	r2, #16
@@ -44,29 +32,28 @@ memset:
 #if ! CALGN(1)+0
 
 /*
- * We need an extra register for this loop - save the return address and
- * use the LR
+ * We need 2 extra registers for this loop - use r8 and the LR
  */
-	str	lr, [sp, #-4]!
-	mov	ip, r1
+	stmfd	sp!, {r8, lr}
+	mov	r8, r1
 	mov	lr, r1
 
 2:	subs	r2, r2, #64
-	stmgeia	r0!, {r1, r3, ip, lr}	@ 64 bytes at a time.
-	stmgeia	r0!, {r1, r3, ip, lr}
-	stmgeia	r0!, {r1, r3, ip, lr}
-	stmgeia	r0!, {r1, r3, ip, lr}
+	stmgeia	ip!, {r1, r3, r8, lr}	@ 64 bytes at a time.
+	stmgeia	ip!, {r1, r3, r8, lr}
+	stmgeia	ip!, {r1, r3, r8, lr}
+	stmgeia	ip!, {r1, r3, r8, lr}
 	bgt	2b
-	ldmeqfd	sp!, {pc}		@ Now <64 bytes to go.
+	ldmeqfd	sp!, {r8, pc}		@ Now <64 bytes to go.
 /*
  * No need to correct the count; we're only testing bits from now on
  */
 	tst	r2, #32
-	stmneia	r0!, {r1, r3, ip, lr}
-	stmneia	r0!, {r1, r3, ip, lr}
+	stmneia	ip!, {r1, r3, r8, lr}
+	stmneia	ip!, {r1, r3, r8, lr}
 	tst	r2, #16
-	stmneia	r0!, {r1, r3, ip, lr}
-	ldr	lr, [sp], #4
+	stmneia	ip!, {r1, r3, r8, lr}
+	ldmfd	sp!, {r8, lr}
 
 #else
 
@@ -75,53 +62,63 @@ memset:
  * whole cache lines at once.
  */
 
-	stmfd	sp!, {r4-r7, lr}
+	stmfd	sp!, {r4-r8, lr}
 	mov	r4, r1
 	mov	r5, r1
 	mov	r6, r1
 	mov	r7, r1
-	mov	ip, r1
+	mov	r8, r1
 	mov	lr, r1
 
 	cmp	r2, #96
-	tstgt	r0, #31
+	tstgt	ip, #31
 	ble	3f
 
-	and	ip, r0, #31
-	rsb	ip, ip, #32
-	sub	r2, r2, ip
-	movs	ip, ip, lsl #(32 - 4)
-	stmcsia	r0!, {r4, r5, r6, r7}
-	stmmiia	r0!, {r4, r5}
-	tst	ip, #(1 << 30)
-	mov	ip, r1
-	strne	r1, [r0], #4
+	and	r8, ip, #31
+	rsb	r8, r8, #32
+	sub	r2, r2, r8
+	movs	r8, r8, lsl #(32 - 4)
+	stmcsia	ip!, {r4, r5, r6, r7}
+	stmmiia	ip!, {r4, r5}
+	tst	r8, #(1 << 30)
+	mov	r8, r1
+	strne	r1, [ip], #4
 
 3:	subs	r2, r2, #64
-	stmgeia	r0!, {r1, r3-r7, ip, lr}
-	stmgeia	r0!, {r1, r3-r7, ip, lr}
+	stmgeia	ip!, {r1, r3-r8, lr}
+	stmgeia	ip!, {r1, r3-r8, lr}
 	bgt	3b
-	ldmeqfd	sp!, {r4-r7, pc}
+	ldmeqfd	sp!, {r4-r8, pc}
 
 	tst	r2, #32
-	stmneia	r0!, {r1, r3-r7, ip, lr}
+	stmneia	ip!, {r1, r3-r8, lr}
 	tst	r2, #16
-	stmneia	r0!, {r4-r7}
-	ldmfd	sp!, {r4-r7, lr}
+	stmneia	ip!, {r4-r7}
+	ldmfd	sp!, {r4-r8, lr}
 
 #endif
 
 4:	tst	r2, #8
-	stmneia	r0!, {r1, r3}
+	stmneia	ip!, {r1, r3}
 	tst	r2, #4
-	strne	r1, [r0], #4
+	strne	r1, [ip], #4
 /*
  * When we get here, we've got less than 4 bytes to zero.  We
  * may have an unaligned pointer as well.
  */
 5:	tst	r2, #2
-	strneb	r1, [r0], #1
-	strneb	r1, [r0], #1
+	strneb	r1, [ip], #1
+	strneb	r1, [ip], #1
 	tst	r2, #1
-	strneb	r1, [r0], #1
+	strneb	r1, [ip], #1
 	mov	pc, lr
+
+6:	subs	r2, r2, #4		@ 1 do we have enough
+	blt	5b			@ 1 bytes to align with?
+	cmp	r3, #2			@ 1
+	strltb	r1, [ip], #1		@ 1
+	strleb	r1, [ip], #1		@ 1
+	strb	r1, [ip], #1		@ 1
+	add	r2, r2, r3		@ 1 (r2 = r2 - (4 - r3))
+	b	1b
+ENDPROC(memset)
diff --git a/payloads/libpayload/include/arm/arch/asm.h b/payloads/libpayload/include/arm/arch/asm.h
index 1c3f7a21c3..2f8859939c 100644
--- a/payloads/libpayload/include/arm/arch/asm.h
+++ b/payloads/libpayload/include/arm/arch/asm.h
@@ -23,9 +23,11 @@
 #if defined __arm__
 #  define ARM(x...)	x
 #  define THUMB(x...)
+#  define W(instr)	instr
 #elif defined __thumb__
 #  define ARM(x...)
 #  define THUMB(x...)	x
+#  define W(instr)	instr.w
 #else
 #  error Not in ARM or thumb mode!
 #endif