From patchwork Fri Oct 18 09:31:42 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthias Maennich X-Patchwork-Id: 11197875 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1AE06112B for ; Fri, 18 Oct 2019 09:32:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E608821897 for ; Fri, 18 Oct 2019 09:32:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="UuMXbS1V" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2409782AbfJRJcJ (ORCPT ); Fri, 18 Oct 2019 05:32:09 -0400 Received: from mail-vs1-f73.google.com ([209.85.217.73]:43770 "EHLO mail-vs1-f73.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2409752AbfJRJcJ (ORCPT ); Fri, 18 Oct 2019 05:32:09 -0400 Received: by mail-vs1-f73.google.com with SMTP id x2so1211535vse.10 for ; Fri, 18 Oct 2019 02:32:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=w96IBFa+LbhPv1tMNCO5lO3g8Rc4+dCAyv83kBM1KbQ=; b=UuMXbS1VDXSrzg400/ZlVcUiZJtpa/YrjX2duCZgzlqBt37ATXDNGUA5Lomr2S98Zo gb89rsts8JNDeagiZNGwvA4LAFHapDI3AgZZAmjI9iKlB6pyzsvupyZySFMKdsIS/NPn QUflCT1aK2m7QD1JrVHDnJu5vafPXa78Qpt3/l9vgnkMPBXRGxIjOpJGiUV7JuUvGyiL 1AwhI97fb6ohGuPxupLhHuFdjSYojeD1VNYTT5qZ/MJoy8TBwDXPWhS4UGC9lqjgq7Qa XVNJBhA9udIzTffkcorFGOIqcVKYHZwE4RWpMf9l8oEfVW8wczIZ0outmdoG9aU8++NR HduA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=w96IBFa+LbhPv1tMNCO5lO3g8Rc4+dCAyv83kBM1KbQ=; b=i9DNIGjzqQ/2ibjLEPpjwGp0NVHWoZT/wmYnh4tH3EP9LlikvGR5E0/n4WD+nCXb+B Zn1yPRDxOw37sN0umj835GZ6aJX/OAfd2jve4l4zUIIadWCexECLkW5IRywFi1Isb6rk f9jMA18prbsnm3muZGgcADSzWUJVJrE90PqnTUp5LYArxW+x9ls6V+N/pyMiRL/xVDIN Lj+061PvQxJtcjG7amZr6t5IOLPXf2+5uGoxQDZ7YprcsJJGthym2lTEgwDnxQmEfGT5 YAViSeqUz25FrgVGF8/SwhkDitnMkt5DJ1jWfW4aVZJwcp09h8J5yfLM3WyTW/G9drLJ qC/A== X-Gm-Message-State: APjAAAUwZ/lvVo7S3syZk2VbDq1Hn5GdIIqmnmaQT+C8Uf1UY92va6kL qVFLN6YfVzQ2rQITPQmgiyK5CHs0pedcMA== X-Google-Smtp-Source: APXvYqx0I59HdbOYdXZ8mLY4td8zpIb3GxCjwY5MOrKW1sOkSQ0BwBPKSyMC8VAXMcnGQ4CsxgRvSBIki69F7A== X-Received: by 2002:a67:c50d:: with SMTP id e13mr4853730vsk.88.1571391125373; Fri, 18 Oct 2019 02:32:05 -0700 (PDT) Date: Fri, 18 Oct 2019 10:31:42 +0100 In-Reply-To: <20191018093143.15997-1-maennich@google.com> Message-Id: <20191018093143.15997-4-maennich@google.com> Mime-Version: 1.0 References: <20191010151443.7399-1-maennich@google.com> <20191018093143.15997-1-maennich@google.com> X-Mailer: git-send-email 2.23.0.866.gb869b98d4c-goog Subject: [PATCH v2 3/4] symbol namespaces: revert to previous __ksymtab name scheme From: Matthias Maennich To: linux-kernel@vger.kernel.org Cc: kernel-team@android.com, maennich@google.com, Jessica Yu , Masahiro Yamada , Martijn Coenen , Lucas De Marchi , Shaun Ruffell , Greg Kroah-Hartman , Will Deacon , linux-kbuild@vger.kernel.org, linux-modules@vger.kernel.org, Stefan Wahren Sender: owner-linux-modules@vger.kernel.org Precedence: bulk List-ID: The introduction of Symbol Namespaces changed the naming schema of the __ksymtab entries from __kysmtab__symbol to __ksymtab_NAMESPACE.symbol. That caused some breakages in tools that depend on the name layout in either the binaries(vmlinux,*.ko) or in System.map. E.g. kmod's depmod would not be able to read System.map without a patch to support symbol namespaces. A warning reported by depmod for namespaced symbols would look like depmod: WARNING: [...]/uas.ko needs unknown symbol usb_stor_adjust_quirks In order to address this issue, revert to the original naming scheme and rather read the __kstrtabns_ entries and their corresponding values from __ksymtab_strings to update the namespace values for symbols. After having read all symbols and handled them in handle_modversions(), the symbols are created. In a second pass, read the __kstrtabns_ entries and update the namespaces accordingly. Reported-by: Stefan Wahren Suggested-by: Masahiro Yamada Fixes: 8651ec01daed ("module: add support for symbol namespaces.") Acked-by: Will Deacon Reviewed-by: Greg Kroah-Hartman Reviewed-by: Masahiro Yamada Signed-off-by: Matthias Maennich --- include/linux/export.h | 14 +++++--------- scripts/mod/modpost.c | 33 ++++++++++++++++++--------------- scripts/mod/modpost.h | 1 + 3 files changed, 24 insertions(+), 24 deletions(-) diff --git a/include/linux/export.h b/include/linux/export.h index 621158ecd2e2..941d075f03d6 100644 --- a/include/linux/export.h +++ b/include/linux/export.h @@ -18,8 +18,6 @@ extern struct module __this_module; #define THIS_MODULE ((struct module *)0) #endif -#define NS_SEPARATOR "." - #ifdef CONFIG_MODVERSIONS /* Mark the CRC weak since genksyms apparently decides not to * generate a checksums for some symbols */ @@ -48,11 +46,11 @@ extern struct module __this_module; * absolute relocations that require runtime processing on relocatable * kernels. */ -#define __KSYMTAB_ENTRY_NS(sym, sec, ns) \ +#define __KSYMTAB_ENTRY_NS(sym, sec) \ __ADDRESSABLE(sym) \ asm(" .section \"___ksymtab" sec "+" #sym "\", \"a\" \n" \ " .balign 4 \n" \ - "__ksymtab_" #ns NS_SEPARATOR #sym ": \n" \ + "__ksymtab_" #sym ": \n" \ " .long " #sym "- . \n" \ " .long __kstrtab_" #sym "- . \n" \ " .long __kstrtabns_" #sym "- . \n" \ @@ -74,16 +72,14 @@ struct kernel_symbol { int namespace_offset; }; #else -#define __KSYMTAB_ENTRY_NS(sym, sec, ns) \ - static const struct kernel_symbol __ksymtab_##sym##__##ns \ - asm("__ksymtab_" #ns NS_SEPARATOR #sym) \ +#define __KSYMTAB_ENTRY_NS(sym, sec) \ + static const struct kernel_symbol __ksymtab_##sym \ __attribute__((section("___ksymtab" sec "+" #sym), used)) \ __aligned(sizeof(void *)) \ = { (unsigned long)&sym, __kstrtab_##sym, __kstrtabns_##sym } #define __KSYMTAB_ENTRY(sym, sec) \ static const struct kernel_symbol __ksymtab_##sym \ - asm("__ksymtab_" #sym) \ __attribute__((section("___ksymtab" sec "+" #sym), used)) \ __aligned(sizeof(void *)) \ = { (unsigned long)&sym, __kstrtab_##sym, NULL } @@ -115,7 +111,7 @@ struct kernel_symbol { static const char __kstrtabns_##sym[] \ __attribute__((section("__ksymtab_strings"), used, aligned(1))) \ = #ns; \ - __KSYMTAB_ENTRY_NS(sym, sec, ns) + __KSYMTAB_ENTRY_NS(sym, sec) #define ___EXPORT_SYMBOL(sym, sec) \ ___export_symbol_common(sym, sec); \ diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 95b1eac656aa..0bf7eab80d9f 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -348,18 +348,11 @@ static enum export export_from_sec(struct elf_info *elf, unsigned int sec) return export_unknown; } -static char *sym_extract_namespace(const char **symname) +static const char *namespace_from_kstrtabns(struct elf_info *info, + Elf_Sym *kstrtabns) { - char *namespace = NULL; - char *ns_separator; - - ns_separator = strchr(*symname, '.'); - if (ns_separator) { - namespace = NOFAIL(strndup(*symname, ns_separator - *symname)); - *symname = ns_separator + 1; - } - - return namespace; + char *value = info->ksymtab_strings + kstrtabns->st_value; + return value[0] ? value : NULL; } static void sym_update_namespace(const char *symname, const char *namespace) @@ -600,6 +593,10 @@ static int parse_elf(struct elf_info *info, const char *filename) info->export_unused_gpl_sec = i; else if (strcmp(secname, "__ksymtab_gpl_future") == 0) info->export_gpl_future_sec = i; + else if (strcmp(secname, "__ksymtab_strings") == 0) + info->ksymtab_strings = (void *)hdr + + sechdrs[i].sh_offset - + sechdrs[i].sh_addr; if (sechdrs[i].sh_type == SHT_SYMTAB) { unsigned int sh_link_idx; @@ -689,7 +686,6 @@ static void handle_modversions(struct module *mod, struct elf_info *info, enum export export; bool is_crc = false; const char *name; - char *namespace; if ((!is_vmlinux(mod->name) || mod->is_dot_o) && strstarts(symname, "__ksymtab")) @@ -762,10 +758,7 @@ static void handle_modversions(struct module *mod, struct elf_info *info, /* All exported symbols */ if (strstarts(symname, "__ksymtab_")) { name = symname + strlen("__ksymtab_"); - namespace = sym_extract_namespace(&name); sym_add_exported(name, mod, export); - sym_update_namespace(name, namespace); - free(namespace); } if (strcmp(symname, "init_module") == 0) mod->has_init = 1; @@ -2061,6 +2054,16 @@ static void read_symbols(const char *modname) handle_moddevtable(mod, &info, sym, symname); } + /* Apply symbol namespaces from __kstrtabns_ entries. */ + for (sym = info.symtab_start; sym < info.symtab_stop; sym++) { + symname = remove_dot(info.strtab + sym->st_name); + + if (strstarts(symname, "__kstrtabns_")) + sym_update_namespace(symname + strlen("__kstrtabns_"), + namespace_from_kstrtabns(&info, + sym)); + } + // check for static EXPORT_SYMBOL_* functions && global vars for (sym = info.symtab_start; sym < info.symtab_stop; sym++) { unsigned char bind = ELF_ST_BIND(sym->st_info); diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h index 92a926d375d2..ad271bc6c313 100644 --- a/scripts/mod/modpost.h +++ b/scripts/mod/modpost.h @@ -143,6 +143,7 @@ struct elf_info { Elf_Section export_gpl_sec; Elf_Section export_unused_gpl_sec; Elf_Section export_gpl_future_sec; + char *ksymtab_strings; char *strtab; char *modinfo; unsigned int modinfo_len;