diff options
Diffstat (limited to 'arch/x86/boot/string.c')
| -rw-r--r-- | arch/x86/boot/string.c | 211 |
1 files changed, 196 insertions, 15 deletions
diff --git a/arch/x86/boot/string.c b/arch/x86/boot/string.c index c4428a176973..b25c6a9303b7 100644 --- a/arch/x86/boot/string.c +++ b/arch/x86/boot/string.c @@ -1,11 +1,9 @@ +// SPDX-License-Identifier: GPL-2.0-only /* -*- linux-c -*- ------------------------------------------------------- * * * Copyright (C) 1991, 1992 Linus Torvalds * Copyright 2007 rPath, Inc. - All Rights Reserved * - * This file is part of the Linux kernel, and is made available under - * the terms of the GNU General Public License version 2. - * * ----------------------------------------------------------------------- */ /* @@ -13,10 +11,15 @@ */ #include <linux/types.h> +#include <linux/compiler.h> +#include <linux/errno.h> +#include <linux/limits.h> #include <asm/asm.h> #include "ctype.h" #include "string.h" +#define KSTRTOX_OVERFLOW (1U << 31) + /* * Undef these macros so that the functions that we provide * here will have the correct names regardless of how string.h @@ -29,16 +32,24 @@ int memcmp(const void *s1, const void *s2, size_t len) { bool diff; - asm("repe; cmpsb" CC_SET(nz) - : CC_OUT(nz) (diff), "+D" (s1), "+S" (s2), "+c" (len)); + asm("repe cmpsb" + : "=@ccnz" (diff), "+D" (s1), "+S" (s2), "+c" (len)); return diff; } +/* + * Clang may lower `memcmp == 0` to `bcmp == 0`. + */ +int bcmp(const void *s1, const void *s2, size_t len) +{ + return memcmp(s1, s2, len); +} + int strcmp(const char *str1, const char *str2) { const unsigned char *s1 = (const unsigned char *)str1; const unsigned char *s2 = (const unsigned char *)str2; - int delta = 0; + int delta; while (*s1 || *s2) { delta = *s1 - *s2; @@ -77,14 +88,6 @@ size_t strnlen(const char *s, size_t maxlen) return (es - s); } -unsigned int atou(const char *s) -{ - unsigned int i = 0; - while (isdigit(*s)) - i = i * 10 + (*s++ - '0'); - return i; -} - /* Works only for digits and letters, but small and fast */ #define TOLOWER(x) ((x) | 0x20) @@ -106,7 +109,6 @@ static unsigned int simple_guess_base(const char *cp) * @endp: A pointer to the end of the parsed string will be placed here * @base: The number base to use */ - unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base) { unsigned long long result = 0; @@ -187,3 +189,182 @@ char *strchr(const char *s, int c) return NULL; return (char *)s; } + +static inline u64 __div_u64_rem(u64 dividend, u32 divisor, u32 *remainder) +{ + union { + u64 v64; + u32 v32[2]; + } d = { dividend }; + u32 upper; + + upper = d.v32[1]; + d.v32[1] = 0; + if (upper >= divisor) { + d.v32[1] = upper / divisor; + upper %= divisor; + } + asm ("divl %2" : "=a" (d.v32[0]), "=d" (*remainder) : + "rm" (divisor), "0" (d.v32[0]), "1" (upper)); + return d.v64; +} + +static inline u64 __div_u64(u64 dividend, u32 divisor) +{ + u32 remainder; + + return __div_u64_rem(dividend, divisor, &remainder); +} + +static inline char _tolower(const char c) +{ + return c | 0x20; +} + +static const char *_parse_integer_fixup_radix(const char *s, unsigned int *base) +{ + if (*base == 0) { + if (s[0] == '0') { + if (_tolower(s[1]) == 'x' && isxdigit(s[2])) + *base = 16; + else + *base = 8; + } else + *base = 10; + } + if (*base == 16 && s[0] == '0' && _tolower(s[1]) == 'x') + s += 2; + return s; +} + +/* + * Convert non-negative integer string representation in explicitly given radix + * to an integer. + * Return number of characters consumed maybe or-ed with overflow bit. + * If overflow occurs, result integer (incorrect) is still returned. + * + * Don't you dare use this function. + */ +static unsigned int _parse_integer(const char *s, + unsigned int base, + unsigned long long *p) +{ + unsigned long long res; + unsigned int rv; + + res = 0; + rv = 0; + while (1) { + unsigned int c = *s; + unsigned int lc = c | 0x20; /* don't tolower() this line */ + unsigned int val; + + if ('0' <= c && c <= '9') + val = c - '0'; + else if ('a' <= lc && lc <= 'f') + val = lc - 'a' + 10; + else + break; + + if (val >= base) + break; + /* + * Check for overflow only if we are within range of + * it in the max base we support (16) + */ + if (unlikely(res & (~0ull << 60))) { + if (res > __div_u64(ULLONG_MAX - val, base)) + rv |= KSTRTOX_OVERFLOW; + } + res = res * base + val; + rv++; + s++; + } + *p = res; + return rv; +} + +static int _kstrtoull(const char *s, unsigned int base, unsigned long long *res) +{ + unsigned long long _res; + unsigned int rv; + + s = _parse_integer_fixup_radix(s, &base); + rv = _parse_integer(s, base, &_res); + if (rv & KSTRTOX_OVERFLOW) + return -ERANGE; + if (rv == 0) + return -EINVAL; + s += rv; + if (*s == '\n') + s++; + if (*s) + return -EINVAL; + *res = _res; + return 0; +} + +/** + * kstrtoull - convert a string to an unsigned long long + * @s: The start of the string. The string must be null-terminated, and may also + * include a single newline before its terminating null. The first character + * may also be a plus sign, but not a minus sign. + * @base: The number base to use. The maximum supported base is 16. If base is + * given as 0, then the base of the string is automatically detected with the + * conventional semantics - If it begins with 0x the number will be parsed as a + * hexadecimal (case insensitive), if it otherwise begins with 0, it will be + * parsed as an octal number. Otherwise it will be parsed as a decimal. + * @res: Where to write the result of the conversion on success. + * + * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error. + * Used as a replacement for the obsolete simple_strtoull. Return code must + * be checked. + */ +int kstrtoull(const char *s, unsigned int base, unsigned long long *res) +{ + if (s[0] == '+') + s++; + return _kstrtoull(s, base, res); +} + +static int _kstrtoul(const char *s, unsigned int base, unsigned long *res) +{ + unsigned long long tmp; + int rv; + + rv = kstrtoull(s, base, &tmp); + if (rv < 0) + return rv; + if (tmp != (unsigned long)tmp) + return -ERANGE; + *res = tmp; + return 0; +} + +/** + * boot_kstrtoul - convert a string to an unsigned long + * @s: The start of the string. The string must be null-terminated, and may also + * include a single newline before its terminating null. The first character + * may also be a plus sign, but not a minus sign. + * @base: The number base to use. The maximum supported base is 16. If base is + * given as 0, then the base of the string is automatically detected with the + * conventional semantics - If it begins with 0x the number will be parsed as a + * hexadecimal (case insensitive), if it otherwise begins with 0, it will be + * parsed as an octal number. Otherwise it will be parsed as a decimal. + * @res: Where to write the result of the conversion on success. + * + * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error. + * Used as a replacement for the simple_strtoull. + */ +int boot_kstrtoul(const char *s, unsigned int base, unsigned long *res) +{ + /* + * We want to shortcut function call, but + * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0. + */ + if (sizeof(unsigned long) == sizeof(unsigned long long) && + __alignof__(unsigned long) == __alignof__(unsigned long long)) + return kstrtoull(s, base, (unsigned long long *)res); + else + return _kstrtoul(s, base, res); +} |