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Date: Fri, 5 Mar 2021 13:21:25 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Paul Burton <paul.burton@...s.com>,
Alexander Lobakin <alobakin@...nk.ru>,
Philippe Mathieu-Daudé <f4bug@...at.org>,
linux-mips@...r.kernel.org, Florian Westphal <fw@...len.de>
Subject: [PATCH 5.4 23/72] MIPS: Drop 32-bit asm string functions
From: Paul Burton <paul.burton@...s.com>
commit 3c0be5849259b729580c23549330973a2dd513a2 upstream.
We have assembly implementations of strcpy(), strncpy(), strcmp() &
strncmp() which:
- Are simple byte-at-a-time loops with no particular optimizations. As
a comment in the code describes, they're "rather naive".
- Offer no clear performance advantage over the generic C
implementations - in microbenchmarks performed by Alexander Lobakin
the asm functions sometimes win & sometimes lose, but generally not
by large margins in either direction.
- Don't support 64-bit kernels, where we already make use of the
generic C implementations.
- Tend to bloat kernel code size due to inlining.
- Don't support CONFIG_FORTIFY_SOURCE.
- Won't support nanoMIPS without rework.
For all of these reasons, delete the asm implementations & make use of
the generic C implementations for 32-bit kernels just like we already do
for 64-bit kernels.
Signed-off-by: Paul Burton <paul.burton@...s.com>
URL: https://lore.kernel.org/linux-mips/a2a35f1cf58d6db19eb4af9b4ae21e35@dlink.ru/
Cc: Alexander Lobakin <alobakin@...nk.ru>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@...at.org>
Cc: linux-mips@...r.kernel.org
Signed-off-by: Florian Westphal <fw@...len.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
arch/mips/include/asm/string.h | 121 -----------------------------------------
1 file changed, 121 deletions(-)
--- a/arch/mips/include/asm/string.h
+++ b/arch/mips/include/asm/string.h
@@ -10,127 +10,6 @@
#ifndef _ASM_STRING_H
#define _ASM_STRING_H
-
-/*
- * Most of the inline functions are rather naive implementations so I just
- * didn't bother updating them for 64-bit ...
- */
-#ifdef CONFIG_32BIT
-
-#ifndef IN_STRING_C
-
-#define __HAVE_ARCH_STRCPY
-static __inline__ char *strcpy(char *__dest, __const__ char *__src)
-{
- char *__xdest = __dest;
-
- __asm__ __volatile__(
- ".set\tnoreorder\n\t"
- ".set\tnoat\n"
- "1:\tlbu\t$1,(%1)\n\t"
- "addiu\t%1,1\n\t"
- "sb\t$1,(%0)\n\t"
- "bnez\t$1,1b\n\t"
- "addiu\t%0,1\n\t"
- ".set\tat\n\t"
- ".set\treorder"
- : "=r" (__dest), "=r" (__src)
- : "0" (__dest), "1" (__src)
- : "memory");
-
- return __xdest;
-}
-
-#define __HAVE_ARCH_STRNCPY
-static __inline__ char *strncpy(char *__dest, __const__ char *__src, size_t __n)
-{
- char *__xdest = __dest;
-
- if (__n == 0)
- return __xdest;
-
- __asm__ __volatile__(
- ".set\tnoreorder\n\t"
- ".set\tnoat\n"
- "1:\tlbu\t$1,(%1)\n\t"
- "subu\t%2,1\n\t"
- "sb\t$1,(%0)\n\t"
- "beqz\t$1,2f\n\t"
- "addiu\t%0,1\n\t"
- "bnez\t%2,1b\n\t"
- "addiu\t%1,1\n"
- "2:\n\t"
- ".set\tat\n\t"
- ".set\treorder"
- : "=r" (__dest), "=r" (__src), "=r" (__n)
- : "0" (__dest), "1" (__src), "2" (__n)
- : "memory");
-
- return __xdest;
-}
-
-#define __HAVE_ARCH_STRCMP
-static __inline__ int strcmp(__const__ char *__cs, __const__ char *__ct)
-{
- int __res;
-
- __asm__ __volatile__(
- ".set\tnoreorder\n\t"
- ".set\tnoat\n\t"
- "lbu\t%2,(%0)\n"
- "1:\tlbu\t$1,(%1)\n\t"
- "addiu\t%0,1\n\t"
- "bne\t$1,%2,2f\n\t"
- "addiu\t%1,1\n\t"
- "bnez\t%2,1b\n\t"
- "lbu\t%2,(%0)\n\t"
-#if defined(CONFIG_CPU_R3000)
- "nop\n\t"
-#endif
- "move\t%2,$1\n"
- "2:\tsubu\t%2,$1\n"
- "3:\t.set\tat\n\t"
- ".set\treorder"
- : "=r" (__cs), "=r" (__ct), "=r" (__res)
- : "0" (__cs), "1" (__ct));
-
- return __res;
-}
-
-#endif /* !defined(IN_STRING_C) */
-
-#define __HAVE_ARCH_STRNCMP
-static __inline__ int
-strncmp(__const__ char *__cs, __const__ char *__ct, size_t __count)
-{
- int __res;
-
- __asm__ __volatile__(
- ".set\tnoreorder\n\t"
- ".set\tnoat\n"
- "1:\tlbu\t%3,(%0)\n\t"
- "beqz\t%2,2f\n\t"
- "lbu\t$1,(%1)\n\t"
- "subu\t%2,1\n\t"
- "bne\t$1,%3,3f\n\t"
- "addiu\t%0,1\n\t"
- "bnez\t%3,1b\n\t"
- "addiu\t%1,1\n"
- "2:\n\t"
-#if defined(CONFIG_CPU_R3000)
- "nop\n\t"
-#endif
- "move\t%3,$1\n"
- "3:\tsubu\t%3,$1\n\t"
- ".set\tat\n\t"
- ".set\treorder"
- : "=r" (__cs), "=r" (__ct), "=r" (__count), "=r" (__res)
- : "0" (__cs), "1" (__ct), "2" (__count));
-
- return __res;
-}
-#endif /* CONFIG_32BIT */
-
#define __HAVE_ARCH_MEMSET
extern void *memset(void *__s, int __c, size_t __count);
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