From patchwork Tue Oct 29 16:58:27 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Rutland X-Patchwork-Id: 178048 Delivered-To: patch@linaro.org Received: by 2002:a92:409a:0:0:0:0:0 with SMTP id d26csp67455ill; Tue, 29 Oct 2019 09:59:04 -0700 (PDT) X-Google-Smtp-Source: APXvYqwinC4ZDyNEFpOBbYI6Yo4aZa2ErOhXSiAqDxYplhLRmGkc2igkDDIvi9WImQhE0q/CXHvd X-Received: by 2002:a05:6402:1ad0:: with SMTP id ba16mr18096587edb.107.1572368344770; Tue, 29 Oct 2019 09:59:04 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1572368344; cv=none; d=google.com; s=arc-20160816; b=RU7HLSHw1wjoQOKgkNIFYmGo0b1EARmodQI8DyGMNQAQ0rcPM8nK/eZ44VofdHhAzJ bnwwc7krr0H2WMuHMLZDrmyhyo6NVlLfH1ESHfp5uXEkfrPwdhEu6JcOxzWAIT8SapdH 91Z3WPAi/b0hBoqfC6Uz4cJzXVLvLy0+eyzapKJ51QGGhns2YkA7oer4X8NyUNAcnyT1 Q6tX+7j20ubdZqREckd6w33y3DxZWpPS3AeYBRwbqgq/2RzV5FKyLhKWR21zMuZxBiWa py6PjWFwJPuY1HSYKx5KZPDWPFmJnvS0rEzVIAEJcaGv8dYTIZ2lkgrCAqzghuHFiL8F QZBQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:references:in-reply-to:message-id:date :subject:cc:to:from; bh=L/trl+ls8G0PlpDrS/qP/gBJZEbSL+as8I1pnXDEWU8=; b=lKP5gxBU8mXVWaxaBvKtyBeJ+TT3IN0FBHZ3TdnEP+0C/58XYhd6+cAcZI5NvwBl6n NpIPsFqcCi9AJGaYlxEnNXonxqjPKXDrjDMOy7QmfNHV26I7m+Ye1Ar4+KIdNF1FgcJZ 57ZjgGwdNHcrcrstTurobUSakQlflvM5v4affdh+7e64zUHNlOdRhy5R9rjtwBA3KbLy 0VQ9hFN1cAuR5fplr5Nlw+PD6iWRAoKlJGr+NYbFVj2RjUKe3OX+bysbQ55h2xis5Ap8 10VURhNhhbQN3KOygHjLnz8/HOtaPHuMDKo+h+H3MRqn8HLEV9mHmbJDT+U0Wvb5ZRD7 KysA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id x24si1609975ejf.1.2019.10.29.09.59.04; Tue, 29 Oct 2019 09:59:04 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390694AbfJ2Q7A (ORCPT + 26 others); Tue, 29 Oct 2019 12:59:00 -0400 Received: from foss.arm.com ([217.140.110.172]:54620 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390643AbfJ2Q7A (ORCPT ); Tue, 29 Oct 2019 12:59:00 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 41AB94B2; Tue, 29 Oct 2019 09:58:59 -0700 (PDT) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id D887C3F71F; Tue, 29 Oct 2019 09:58:56 -0700 (PDT) From: Mark Rutland To: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org, amit.kachhap@arm.com, catalin.marinas@arm.com, deller@gmx.de, duwe@suse.de, James.Bottomley@HansenPartnership.com, james.morse@arm.com, jeyu@kernel.org, jpoimboe@redhat.com, jthierry@redhat.com, linux-parisc@vger.kernel.org, mark.rutland@arm.com, mingo@redhat.com, peterz@infradead.org, rostedt@goodmis.org, svens@stackframe.org, takahiro.akashi@linaro.org, will@kernel.org Subject: [PATCHv2 3/8] arm64: module: rework special section handling Date: Tue, 29 Oct 2019 16:58:27 +0000 Message-Id: <20191029165832.33606-4-mark.rutland@arm.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20191029165832.33606-1-mark.rutland@arm.com> References: <20191029165832.33606-1-mark.rutland@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When we load a module, we have to perform some special work for a couple of named sections. To do this, we iterate over all of the module's sections, and perform work for each section we recognize. To make it easier to handle the unexpected absence of a section, and to make the section-specific logic easer to read, let's factor the section search into a helper. Similar is already done in the core module loader, and other architectures (and ideally we'd unify these in future). If we expect a module to have an ftrace trampoline section, but it doesn't have one, we'll now reject loading the module. When ARM64_MODULE_PLTS is selected, any correctly built module should have one (and this is assumed by arm64's ftrace PLT code) and the absence of such a section implies something has gone wrong at build time. Subsequent patches will make use of the new helper. Signed-off-by: Mark Rutland Reviewed-by: Ard Biesheuvel Cc: Catalin Marinas Cc: James Morse Cc: Will Deacon --- arch/arm64/kernel/module.c | 35 ++++++++++++++++++++++++++--------- 1 file changed, 26 insertions(+), 9 deletions(-) -- 2.11.0 Reviewed-by: Miroslav Benes diff --git a/arch/arm64/kernel/module.c b/arch/arm64/kernel/module.c index 03ff15bffbb6..763a86d52fef 100644 --- a/arch/arm64/kernel/module.c +++ b/arch/arm64/kernel/module.c @@ -470,22 +470,39 @@ int apply_relocate_add(Elf64_Shdr *sechdrs, return -ENOEXEC; } -int module_finalize(const Elf_Ehdr *hdr, - const Elf_Shdr *sechdrs, - struct module *me) +static const Elf_Shdr *find_section(const Elf_Ehdr *hdr, + const Elf_Shdr *sechdrs, + const char *name) { const Elf_Shdr *s, *se; const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++) { - if (strcmp(".altinstructions", secstrs + s->sh_name) == 0) - apply_alternatives_module((void *)s->sh_addr, s->sh_size); + if (strcmp(name, secstrs + s->sh_name) == 0) + return s; + } + + return NULL; +} + +int module_finalize(const Elf_Ehdr *hdr, + const Elf_Shdr *sechdrs, + struct module *me) +{ + const Elf_Shdr *s; + + s = find_section(hdr, sechdrs, ".altinstructions"); + if (s) + apply_alternatives_module((void *)s->sh_addr, s->sh_size); + #ifdef CONFIG_ARM64_MODULE_PLTS - if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE) && - !strcmp(".text.ftrace_trampoline", secstrs + s->sh_name)) - me->arch.ftrace_trampoline = (void *)s->sh_addr; -#endif + if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE)) { + s = find_section(hdr, sechdrs, ".text.ftrace_trampoline"); + if (!s) + return -ENOEXEC; + me->arch.ftrace_trampoline = (void *)s->sh_addr; } +#endif return 0; }