From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4F512C04EB9 for ; Thu, 6 Dec 2018 10:37:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EBABB214C1 for ; Thu, 6 Dec 2018 10:37:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EBABB214C1 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=cn.fujitsu.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729502AbeLFKht (ORCPT ); Thu, 6 Dec 2018 05:37:49 -0500 Received: from mail.cn.fujitsu.com ([183.91.158.132]:23319 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727763AbeLFKhs (ORCPT ); Thu, 6 Dec 2018 05:37:48 -0500 X-IronPort-AV: E=Sophos;i="5.56,321,1539619200"; d="scan'208";a="49118429" Received: from unknown (HELO cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 06 Dec 2018 18:37:47 +0800 Received: from G08CNEXCHPEKD01.g08.fujitsu.local (unknown [10.167.33.80]) by cn.fujitsu.com (Postfix) with ESMTP id C7E3B4B7349C; Thu, 6 Dec 2018 18:37:47 +0800 (CST) Received: from localhost.localdomain (10.167.225.56) by G08CNEXCHPEKD01.g08.fujitsu.local (10.167.33.89) with Microsoft SMTP Server (TLS) id 14.3.408.0; Thu, 6 Dec 2018 18:37:54 +0800 Date: Thu, 6 Dec 2018 18:37:20 +0800 From: Chao Fan To: Borislav Petkov CC: Masayoshi Mizuma , , , , , , , , , Subject: Re: [PATCH v12 1/5] x86/boot: Add get_acpi_rsdp() to parse RSDP in cmdline from KEXEC Message-ID: <20181206103720.GA2046@localhost.localdomain> References: <20181129081631.11139-1-fanc.fnst@cn.fujitsu.com> <20181129081631.11139-2-fanc.fnst@cn.fujitsu.com> <20181129211003.saxfvyboxpsn5mdr@gabell> <20181130024346.GB30941@localhost.localdomain> <20181130173515.6zx5wvs52s5aqnge@gabell> <20181201060539.GD30941@localhost.localdomain> <20181204184220.GC16705@zn.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20181204184220.GC16705@zn.tnic> User-Agent: Mutt/1.10.1 (2018-07-13) X-Originating-IP: [10.167.225.56] X-yoursite-MailScanner-ID: C7E3B4B7349C.ACA7B X-yoursite-MailScanner: Found to be clean X-yoursite-MailScanner-From: fanc.fnst@cn.fujitsu.com Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Boris, Baoquan and Masa, When copying kstrtoull() and functions needed to arch/x86/boot/string.c, I got an error in LD period: LD arch/x86/boot/setup.elf ld: arch/x86/boot/string.o: in function `div_u64_rem': /home/cfan/code/tip/./include/linux/math64.h:28: undefined reference to `__udivdi3' make[1]: *** [arch/x86/boot/Makefile:105: arch/x86/boot/setup.elf] Error 1 make: *** [arch/x86/Makefile:289: bzImage] Error 2 I google it and the key problem is div_u64(ULLONG_MAX - val, base)) when dividend is u64 and divisor is u32, the dividend must be a variable, since the result will be stored in the first variable. So here when I changed it to ((ULLONG_MAX - val) / base), I got the same error. But what puzzled me is, why the cdoe in lib/kstrtox.c works well. And in old version PATCHSET, I ever copy the code to arch/x86/boot/compressed/misc.c, it also worked well. So I wonder if there are some options I miss or some problems. The patch is below. Thanks, Chao Fan diff --git a/arch/x86/boot/string.c b/arch/x86/boot/string.c index c4428a176973..62ffe0437c8e 100644 --- a/arch/x86/boot/string.c +++ b/arch/x86/boot/string.c @@ -13,6 +13,9 @@ */ #include +#include +#include +#include #include #include "ctype.h" #include "string.h" @@ -187,3 +190,112 @@ char *strchr(const char *s, int c) return NULL; return (char *)s; } + +static inline char _tolower(const char c) +{ + return c | 0x20; +} + +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. + */ +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); +} diff --git a/arch/x86/boot/string.h b/arch/x86/boot/string.h index 3d78e27077f4..9619c8990d95 100644 --- a/arch/x86/boot/string.h +++ b/arch/x86/boot/string.h @@ -29,4 +29,6 @@ extern unsigned int atou(const char *s); extern unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base); +#define KSTRTOX_OVERFLOW (1U << 31) + #endif /* BOOT_STRING_H */