From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f73.google.com (mail-wm1-f73.google.com [209.85.128.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AEB053E0C73 for ; Thu, 5 Mar 2026 16:55:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.73 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772729728; cv=none; b=jVInKh0S3swQ34nacjtWEZG4P+3P3WHyiE/kyclCFPuP2eO/6OjYbDrvovcrJL7uy98UK9hg9jrzzRWCWPHdvqxF8l4waPGqN35TJVM/YW5oRdEiS7UTv+HaJU8ZB6Mmt1qSPhNpwVWfnTBHiZws+FAscXRaDOK1E4SReDaR7HE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772729728; c=relaxed/simple; bh=TpZmRegtqEbXTTVHSkwGbHY5Ll9KMK2Mxg+dapA2VWM=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=LgAHDTw7rgPcteRIsF67MYrhZqtMLnQnYoEIyxmseEp062CCEeSFpjKHEv4QQChtJpDVLBCd/YbODC5OLDjSWQwd8wOSa2shuW+GI/PoZKFvkJEMjfs/qaskUeMgCG38ExwSJs8TTyq9l3h/OdUrEU51Um7ldDmmD0PavTZd7TM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--sidnayyar.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=ugY5rrlR; arc=none smtp.client-ip=209.85.128.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--sidnayyar.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ugY5rrlR" Received: by mail-wm1-f73.google.com with SMTP id 5b1f17b1804b1-483a2db68caso67751705e9.0 for ; Thu, 05 Mar 2026 08:55:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1772729725; x=1773334525; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=kH4l5sUjOP0TtrWWkDh0aa89yXT1o3HsEp7IF0XRzwQ=; b=ugY5rrlRB3GFRvPh3T6r9OFOU0kUHoW2nUmpQ3RWbVy9Ache2mr30uQ6ARdAj80dWi jsLe07W8a7Jtht1lRjF0pGzpPDJY2+MJ1kxccGyjUJAK7HRbUyY9jwBdoV/TQ9K52FNo CU5k2qQLLWi5TRPnV+5Z6MJXXbSPWzDHSq6aaKml8VTZxElK1HqEvhmf9dvug97uqvxX heCENyeuBt+S8MqU0a2DwM/PpQLz7VWNx8kxRNMSsCXRyE6jheG85VNyyAYcsTg2w1DL 3n6VIjzoZPAgS9ER42Q9I6rJjYUjnuXiRmo1PW/4es378Z8uMlg5ilJqLpURCH1zrDI5 g66Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1772729725; x=1773334525; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=kH4l5sUjOP0TtrWWkDh0aa89yXT1o3HsEp7IF0XRzwQ=; b=lUWfwtpJCkSC49pWDO4FyoW1HDDKqJWSr4tKU3kx2xzzDfUr6IZzjM6xwUrWaXuvbL qnjhy4zaXBEnc4mX/RDkCZguGKLna85JADyMeGPy02xXXG52nfXnmmZlgGVZYfEJDS+f EcD8JXfBNDLmXYFZv1jptpeTXt+1UPOdNg0GkQX9b/T435H5tiU3p3fCNJHB+9fgZ2Fx I/lIPagTDIFWGrs8XzqhULK3B5KV2NFZKEw5Q0kqdzXdJtTUyT/SWD552faBlu+O+UlX XtuBVX756Dc57hVRYP5huDTosN4fkW7GxXXPKyuB+VNr7v9XKwpBLNjV8HPBpJJWjtP2 X42w== X-Gm-Message-State: AOJu0YyvmDKWO2nI4mW2s3T74jf9TI+/jf/qZ8qNgt6pNOAnaj02k2Hc Y85t1qt9fVpG0l4/MVwOcevp0NO8k4/u50l0GmPc0rY5HlWw7+XiJfZNxx2D770HSfY27EF7upR JtkDWgfZXvuQ/VMJxxw== X-Received: from wmim3.prod.google.com ([2002:a7b:cb83:0:b0:483:a1ee:5eca]) (user=sidnayyar job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:314f:b0:477:9a28:b0a4 with SMTP id 5b1f17b1804b1-4852354764bmr3796895e9.0.1772729725045; Thu, 05 Mar 2026 08:55:25 -0800 (PST) Date: Thu, 05 Mar 2026 16:55:20 +0000 In-Reply-To: <20260305-kflagstab-v4-0-6a76bf8b83c7@google.com> Precedence: bulk X-Mailing-List: linux-modules@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260305-kflagstab-v4-0-6a76bf8b83c7@google.com> X-Mailer: b4 0.14.3 Message-ID: <20260305-kflagstab-v4-4-6a76bf8b83c7@google.com> Subject: [PATCH v4 4/8] module loader: use kflagstab instead of *_gpl sections From: Siddharth Nayyar To: Luis Chamberlain , Petr Pavlu , Daniel Gomez , Sami Tolvanen , Aaron Tomlin , Arnd Bergmann , Nathan Chancellor , Nicolas Schier , Jonathan Corbet , Shuah Khan Cc: linux-modules@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-doc@vger.kernel.org, Siddharth Nayyar , maennich@google.com, gprocida@google.com Content-Type: text/plain; charset="utf-8" Read kflagstab section for vmlinux and modules to determine whether kernel symbols are GPL only. This patch eliminates the need for fragmenting the ksymtab for infering the value of GPL-only symbol flag. The fragmentation of ksymtab is removed in subsequent patches. Signed-off-by: Siddharth Nayyar --- include/linux/module.h | 1 + kernel/module/internal.h | 1 + kernel/module/main.c | 55 +++++++++++++++++++++++++----------------------- 3 files changed, 31 insertions(+), 26 deletions(-) diff --git a/include/linux/module.h b/include/linux/module.h index 14f391b186c6..aee3accba73c 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -418,6 +418,7 @@ struct module { /* Exported symbols */ const struct kernel_symbol *syms; const u32 *crcs; + const u8 *flagstab; unsigned int num_syms; #ifdef CONFIG_ARCH_USES_CFI_TRAPS diff --git a/kernel/module/internal.h b/kernel/module/internal.h index 618202578b42..69b84510e097 100644 --- a/kernel/module/internal.h +++ b/kernel/module/internal.h @@ -57,6 +57,7 @@ extern const struct kernel_symbol __start___ksymtab_gpl[]; extern const struct kernel_symbol __stop___ksymtab_gpl[]; extern const u32 __start___kcrctab[]; extern const u32 __start___kcrctab_gpl[]; +extern const u8 __start___kflagstab[]; #define KMOD_PATH_LEN 256 extern char modprobe_path[]; diff --git a/kernel/module/main.c b/kernel/module/main.c index c3ce106c70af..d237fa4e0737 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -11,6 +11,7 @@ #include #include #include +#include #include #include #include @@ -87,7 +88,7 @@ struct mod_tree_root mod_tree __cacheline_aligned = { struct symsearch { const struct kernel_symbol *start, *stop; const u32 *crcs; - enum mod_license license; + const u8 *flagstab; }; /* @@ -364,19 +365,21 @@ static bool find_exported_symbol_in_section(const struct symsearch *syms, struct find_symbol_arg *fsa) { struct kernel_symbol *sym; - - if (!fsa->gplok && syms->license == GPL_ONLY) - return false; + u8 sym_flags; sym = bsearch(fsa->name, syms->start, syms->stop - syms->start, sizeof(struct kernel_symbol), cmp_name); if (!sym) return false; + sym_flags = *(syms->flagstab + (sym - syms->start)); + if (!fsa->gplok && (sym_flags & KSYM_FLAG_GPL_ONLY)) + return false; + fsa->owner = owner; fsa->crc = symversion(syms->crcs, sym - syms->start); fsa->sym = sym; - fsa->license = syms->license; + fsa->license = (sym_flags & KSYM_FLAG_GPL_ONLY) ? GPL_ONLY : NOT_GPL_ONLY; return true; } @@ -387,36 +390,31 @@ static bool find_exported_symbol_in_section(const struct symsearch *syms, */ bool find_symbol(struct find_symbol_arg *fsa) { - static const struct symsearch arr[] = { - { __start___ksymtab, __stop___ksymtab, __start___kcrctab, - NOT_GPL_ONLY }, - { __start___ksymtab_gpl, __stop___ksymtab_gpl, - __start___kcrctab_gpl, - GPL_ONLY }, + const struct symsearch syms = { + .start = __start___ksymtab, + .stop = __stop___ksymtab, + .crcs = __start___kcrctab, + .flagstab = __start___kflagstab, }; struct module *mod; - unsigned int i; - for (i = 0; i < ARRAY_SIZE(arr); i++) - if (find_exported_symbol_in_section(&arr[i], NULL, fsa)) - return true; + if (find_exported_symbol_in_section(&syms, NULL, fsa)) + return true; list_for_each_entry_rcu(mod, &modules, list, lockdep_is_held(&module_mutex)) { - struct symsearch arr[] = { - { mod->syms, mod->syms + mod->num_syms, mod->crcs, - NOT_GPL_ONLY }, - { mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms, - mod->gpl_crcs, - GPL_ONLY }, + const struct symsearch syms = { + .start = mod->syms, + .stop = mod->syms + mod->num_syms, + .crcs = mod->crcs, + .flagstab = mod->flagstab, }; if (mod->state == MODULE_STATE_UNFORMED) continue; - for (i = 0; i < ARRAY_SIZE(arr); i++) - if (find_exported_symbol_in_section(&arr[i], mod, fsa)) - return true; + if (find_exported_symbol_in_section(&syms, mod, fsa)) + return true; } pr_debug("Failed to find symbol %s\n", fsa->name); @@ -2614,6 +2612,7 @@ static int find_module_sections(struct module *mod, struct load_info *info) sizeof(*mod->gpl_syms), &mod->num_gpl_syms); mod->gpl_crcs = section_addr(info, "__kcrctab_gpl"); + mod->flagstab = section_addr(info, "__kflagstab"); #ifdef CONFIG_CONSTRUCTORS mod->ctors = section_objs(info, ".ctors", @@ -2817,8 +2816,12 @@ static int move_module(struct module *mod, struct load_info *info) return ret; } -static int check_export_symbol_versions(struct module *mod) +static int check_export_symbol_sections(struct module *mod) { + if (mod->num_syms && !mod->flagstab) { + pr_err("%s: no flags for exported symbols\n", mod->name); + return -ENOEXEC; + } #ifdef CONFIG_MODVERSIONS if ((mod->num_syms && !mod->crcs) || (mod->num_gpl_syms && !mod->gpl_crcs)) { @@ -3434,7 +3437,7 @@ static int load_module(struct load_info *info, const char __user *uargs, if (err) goto free_unload; - err = check_export_symbol_versions(mod); + err = check_export_symbol_sections(mod); if (err) goto free_unload; -- 2.53.0.473.g4a7958ca14-goog