ARM: 7449/1: use generic strnlen_user and strncpy_from_user functions

This patch implements the word-at-a-time interface for ARM using the
same algorithm as x86. We use the fls macro from ARMv5 onwards, where
we have a clz instruction available which saves us a mov instruction
when targetting Thumb-2. For older CPUs, we use the magic 0x0ff0001
constant. Big-endian configurations make use of the implementation from
asm-generic.

With this implemented, we can replace our byte-at-a-time strnlen_user
and strncpy_from_user functions with the optimised generic versions.

Reviewed-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

3 files changed, 0 insertions, 84 deletions

diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile
index 992769ae259..d5060dab6e5 100644
--- a/arch/arm/lib/Makefile
+++ b/arch/arm/lib/Makefile
@@ -8,7 +8,6 @@ lib-y		:= backtrace.o changebit.o csumipv6.o csumpartial.o   \
 		   csumpartialcopy.o csumpartialcopyuser.o clearbit.o \
 		   delay.o findbit.o memchr.o memcpy.o		      \
 		   memmove.o memset.o memzero.o setbit.o              \
-		   strncpy_from_user.o strnlen_user.o                 \
 		   strchr.o strrchr.o                                 \
 		   testchangebit.o testclearbit.o testsetbit.o        \
 		   ashldi3.o ashrdi3.o lshrdi3.o muldi3.o             \
diff --git a/arch/arm/lib/strncpy_from_user.S b/arch/arm/lib/strncpy_from_user.S
deleted file mode 100644
index f202d7bd164..00000000000
--- a/arch/arm/lib/strncpy_from_user.S
+++ /dev/null
@@ -1,43 +0,0 @@
-/*
- *  linux/arch/arm/lib/strncpy_from_user.S
- *
- *  Copyright (C) 1995-2000 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>
-#include <asm/errno.h>
-
-	.text
-	.align	5
-
-/*
- * Copy a string from user space to kernel space.
- *  r0 = dst, r1 = src, r2 = byte length
- * returns the number of characters copied (strlen of copied string),
- *  -EFAULT on exception, or "len" if we fill the whole buffer
- */
-ENTRY(__strncpy_from_user)
-	mov	ip, r1
-1:	subs	r2, r2, #1
-	ldrusr	r3, r1, 1, pl
-	bmi	2f
-	strb	r3, [r0], #1
-	teq	r3, #0
-	bne	1b
-	sub	r1, r1, #1	@ take NUL character out of count
-2:	sub	r0, r1, ip
-	mov	pc, lr
-ENDPROC(__strncpy_from_user)
-
-	.pushsection .fixup,"ax"
-	.align	0
-9001:	mov	r3, #0
-	strb	r3, [r0, #0]	@ null terminate
-	mov	r0, #-EFAULT
-	mov	pc, lr
-	.popsection
-
diff --git a/arch/arm/lib/strnlen_user.S b/arch/arm/lib/strnlen_user.S
deleted file mode 100644
index 0ecbb459c4f..00000000000
--- a/arch/arm/lib/strnlen_user.S
+++ /dev/null
@@ -1,40 +0,0 @@
-/*
- *  linux/arch/arm/lib/strnlen_user.S
- *
- *  Copyright (C) 1995-2000 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>
-#include <asm/errno.h>
-
-	.text
-	.align	5
-
-/* Prototype: unsigned long __strnlen_user(const char *str, long n)
- * Purpose  : get length of a string in user memory
- * Params   : str - address of string in user memory
- * Returns  : length of string *including terminator*
- *	      or zero on exception, or n + 1 if too long
- */
-ENTRY(__strnlen_user)
-	mov	r2, r0
-1:
-	ldrusr	r3, r0, 1
-	teq	r3, #0
-	beq	2f
-	subs	r1, r1, #1
-	bne	1b
-	add	r0, r0, #1
-2:	sub	r0, r0, r2
-	mov	pc, lr
-ENDPROC(__strnlen_user)
-
-	.pushsection .fixup,"ax"
-	.align	0
-9001:	mov	r0, #0
-	mov	pc, lr
-	.popsection