From 12a0ef7b0ac38677bd2d85f33df5ca0a57868819 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Wed, 6 Nov 2013 17:20:22 +0000 Subject: [PATCH] arm64: use generic strnlen_user and strncpy_from_user functions This patch implements the word-at-a-time interface for arm64 using the same algorithm as ARM. We use the fls64 macro, which expands to a clz instruction via a compiler builtin. 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. Signed-off-by: Will Deacon Signed-off-by: Catalin Marinas --- arch/arm64/Kconfig | 2 + arch/arm64/include/asm/uaccess.h | 25 ++---------- arch/arm64/include/asm/word-at-a-time.h | 54 +++++++++++++++++++++++++ arch/arm64/kernel/arm64ksyms.c | 5 +-- arch/arm64/lib/Makefile | 8 ++-- arch/arm64/lib/strncpy_from_user.S | 50 ----------------------- arch/arm64/lib/strnlen_user.S | 47 --------------------- 7 files changed, 64 insertions(+), 127 deletions(-) create mode 100644 arch/arm64/include/asm/word-at-a-time.h delete mode 100644 arch/arm64/lib/strncpy_from_user.S delete mode 100644 arch/arm64/lib/strnlen_user.S diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 6d4dd22ee4b7..295bf2de7128 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -17,6 +17,8 @@ config ARM64 select GENERIC_IRQ_SHOW select GENERIC_SCHED_CLOCK select GENERIC_SMP_IDLE_THREAD + select GENERIC_STRNCPY_FROM_USER + select GENERIC_STRNLEN_USER select GENERIC_TIME_VSYSCALL select HARDIRQS_SW_RESEND select HAVE_ARCH_TRACEHOOK diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index 7ecc2b23882e..6c0f684aca81 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -100,6 +100,7 @@ static inline void set_fs(mm_segment_t fs) }) #define access_ok(type, addr, size) __range_ok(addr, size) +#define user_addr_max get_fs /* * The "__xxx" versions of the user access functions do not verify the address @@ -240,9 +241,6 @@ extern unsigned long __must_check __copy_to_user(void __user *to, const void *fr extern unsigned long __must_check __copy_in_user(void __user *to, const void __user *from, unsigned long n); extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n); -extern unsigned long __must_check __strncpy_from_user(char *to, const char __user *from, unsigned long count); -extern unsigned long __must_check __strnlen_user(const char __user *s, long n); - static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n) { if (access_ok(VERIFY_READ, from, n)) @@ -276,24 +274,9 @@ static inline unsigned long __must_check clear_user(void __user *to, unsigned lo return n; } -static inline long __must_check strncpy_from_user(char *dst, const char __user *src, long count) -{ - long res = -EFAULT; - if (access_ok(VERIFY_READ, src, 1)) - res = __strncpy_from_user(dst, src, count); - return res; -} - -#define strlen_user(s) strnlen_user(s, ~0UL >> 1) +extern long strncpy_from_user(char *dest, const char __user *src, long count); -static inline long __must_check strnlen_user(const char __user *s, long n) -{ - unsigned long res = 0; - - if (__addr_ok(s)) - res = __strnlen_user(s, n); - - return res; -} +extern __must_check long strlen_user(const char __user *str); +extern __must_check long strnlen_user(const char __user *str, long n); #endif /* __ASM_UACCESS_H */ diff --git a/arch/arm64/include/asm/word-at-a-time.h b/arch/arm64/include/asm/word-at-a-time.h new file mode 100644 index 000000000000..27a167d044d9 --- /dev/null +++ b/arch/arm64/include/asm/word-at-a-time.h @@ -0,0 +1,54 @@ +/* + * Copyright (C) 2013 ARM Ltd. + * + * 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. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ +#ifndef __ASM_WORD_AT_A_TIME_H +#define __ASM_WORD_AT_A_TIME_H + +#ifndef __AARCH64EB__ + +#include + +struct word_at_a_time { + const unsigned long one_bits, high_bits; +}; + +#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) } + +static inline unsigned long has_zero(unsigned long a, unsigned long *bits, + const struct word_at_a_time *c) +{ + unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits; + *bits = mask; + return mask; +} + +#define prep_zero_mask(a, bits, c) (bits) + +static inline unsigned long create_zero_mask(unsigned long bits) +{ + bits = (bits - 1) & ~bits; + return bits >> 7; +} + +static inline unsigned long find_zero(unsigned long mask) +{ + return fls64(mask) >> 3; +} + +#else /* __AARCH64EB__ */ +#include +#endif + +#endif /* __ASM_WORD_AT_A_TIME_H */ diff --git a/arch/arm64/kernel/arm64ksyms.c b/arch/arm64/kernel/arm64ksyms.c index e7ee770c0697..338b568cd8ae 100644 --- a/arch/arm64/kernel/arm64ksyms.c +++ b/arch/arm64/kernel/arm64ksyms.c @@ -29,13 +29,10 @@ #include - /* user mem (segment) */ -EXPORT_SYMBOL(__strnlen_user); -EXPORT_SYMBOL(__strncpy_from_user); - EXPORT_SYMBOL(copy_page); EXPORT_SYMBOL(clear_page); + /* user mem (segment) */ EXPORT_SYMBOL(__copy_from_user); EXPORT_SYMBOL(__copy_to_user); EXPORT_SYMBOL(__clear_user); diff --git a/arch/arm64/lib/Makefile b/arch/arm64/lib/Makefile index 59acc0ef0462..328ce1a99daa 100644 --- a/arch/arm64/lib/Makefile +++ b/arch/arm64/lib/Makefile @@ -1,6 +1,4 @@ -lib-y := bitops.o delay.o \ - strncpy_from_user.o strnlen_user.o clear_user.o \ - copy_from_user.o copy_to_user.o copy_in_user.o \ - copy_page.o clear_page.o \ - memchr.o memcpy.o memmove.o memset.o \ +lib-y := bitops.o clear_user.o delay.o copy_from_user.o \ + copy_to_user.o copy_in_user.o copy_page.o \ + clear_page.o memchr.o memcpy.o memmove.o memset.o \ strchr.o strrchr.o diff --git a/arch/arm64/lib/strncpy_from_user.S b/arch/arm64/lib/strncpy_from_user.S deleted file mode 100644 index 56e448a831a0..000000000000 --- a/arch/arm64/lib/strncpy_from_user.S +++ /dev/null @@ -1,50 +0,0 @@ -/* - * Based on arch/arm/lib/strncpy_from_user.S - * - * Copyright (C) 1995-2000 Russell King - * Copyright (C) 2012 ARM Ltd. - * - * 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. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program. If not, see . - */ - -#include -#include -#include - - .text - .align 5 - -/* - * Copy a string from user space to kernel space. - * x0 = dst, x1 = src, x2 = 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 x4, x1 -1: subs x2, x2, #1 - bmi 2f -USER(9f, ldrb w3, [x1], #1 ) - strb w3, [x0], #1 - cbnz w3, 1b - sub x1, x1, #1 // take NUL character out of count -2: sub x0, x1, x4 - ret -ENDPROC(__strncpy_from_user) - - .section .fixup,"ax" - .align 0 -9: strb wzr, [x0] // null terminate - mov x0, #-EFAULT - ret - .previous diff --git a/arch/arm64/lib/strnlen_user.S b/arch/arm64/lib/strnlen_user.S deleted file mode 100644 index 7f7b176a5646..000000000000 --- a/arch/arm64/lib/strnlen_user.S +++ /dev/null @@ -1,47 +0,0 @@ -/* - * Based on arch/arm/lib/strnlen_user.S - * - * Copyright (C) 1995-2000 Russell King - * Copyright (C) 2012 ARM Ltd. - * - * 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. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program. If not, see . - */ - -#include -#include -#include - - .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 if too long - */ -ENTRY(__strnlen_user) - mov x2, x0 -1: subs x1, x1, #1 - b.mi 2f -USER(9f, ldrb w3, [x0], #1 ) - cbnz w3, 1b -2: sub x0, x0, x2 - ret -ENDPROC(__strnlen_user) - - .section .fixup,"ax" - .align 0 -9: mov x0, #0 - ret - .previous -- 2.34.1