From patchwork Fri Jul 30 11:24:38 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 12411079 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=-17.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 21832C4338F for ; Fri, 30 Jul 2021 11:32:06 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D4B236103B for ; Fri, 30 Jul 2021 11:32:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org D4B236103B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=j9i1hGXbSlKgUwU9bK9eR+FebipL86U8kamH99BzfvQ=; b=Fep4AwYtP9otuf Ge/e5jvf+4FEUhSXwn8q7qnYyr0Sqbsdm2peb43fDr1M9dZ+M7W1tPn2RtkYW6V/+R6DEWMF6C1XC R8m1tf57+qxZVRGs42J9h80v2CvF0UhhcxK3zoXYCQsqIVS8RXzT6Aiia596kSJrhR4TTbRfZkld7 DjlmuIPHhcuvQ1INjj5Ku+yBstKhukyQDMe+CmG4gIM2w6GsyLOIWB83i7aVeTeL/S9b9ZivwVXMV CJF8/mRgcLtKBIvZV/BWlQbNf8NzQ84MbvSC6j1ZixPLwNwzo8op++4ZsoOI9kORTAN9jGt1gvuzJ s+WDrR6QixzZ3EtF9ccA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1m9Qi2-008JSB-Qh; Fri, 30 Jul 2021 11:29:46 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1m9Qe0-008HXE-1n for linux-arm-kernel@lists.infradead.org; Fri, 30 Jul 2021 11:25:37 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 4105261052; Fri, 30 Jul 2021 11:25:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1627644335; bh=XYxWvbxyG0p9zfJU0ZUjM8nEm2BIbKxsvYb0x1zSw14=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=oXn/lVUuDMaltds6be6oJVxjRZ/VBeOCSaFGWu6JFjW0/SyeQnRXW9UyXBsGaArEt azn5Fq0iRMy/W+Q+LhfiMIbvqB7IhREw/AzOJqzZaNwtZxjQw34UKEkGg2Gk159NXp OiQnmbbdtuVo9ZG6ldfBylNLA3OSOe8uQNqoHb02XF8CTDhFvv+OybPvkWw2CnAXJo iDd3J7eWI4VeVNu9+efYuSbX1Ak8M/t84b+orAXLy1nK6yNCv90kyZwv8TldoUDf5c bgg1yuwNQCEv5mhjIRJp+1n0n8RXRnvqMTRdmA0MZIgBhgEgXini2tXU591nOm+IKm ITZ5e1N3x5RYQ== From: Will Deacon To: linux-arm-kernel@lists.infradead.org Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, Will Deacon , Catalin Marinas , Marc Zyngier , Greg Kroah-Hartman , Peter Zijlstra , Morten Rasmussen , Qais Yousef , Suren Baghdasaryan , Quentin Perret , Tejun Heo , Johannes Weiner , Ingo Molnar , Juri Lelli , Vincent Guittot , "Rafael J. Wysocki" , Dietmar Eggemann , Daniel Bristot de Oliveira , Valentin Schneider , Mark Rutland , kernel-team@android.com Subject: [PATCH v11 11/16] arm64: exec: Adjust affinity for compat tasks with mismatched 32-bit EL0 Date: Fri, 30 Jul 2021 12:24:38 +0100 Message-Id: <20210730112443.23245-12-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210730112443.23245-1-will@kernel.org> References: <20210730112443.23245-1-will@kernel.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210730_042536_178677_F7BF6F12 X-CRM114-Status: GOOD ( 18.20 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org When exec'ing a 32-bit task on a system with mismatched support for 32-bit EL0, try to ensure that it starts life on a CPU that can actually run it. Similarly, when exec'ing a 64-bit task on such a system, try to restore the old affinity mask if it was previously restricted. Reviewed-by: Daniel Bristot de Oliveira Reviewed-by: Quentin Perret Signed-off-by: Will Deacon --- arch/arm64/include/asm/elf.h | 6 ++---- arch/arm64/kernel/process.c | 39 +++++++++++++++++++++++++++++++++++- 2 files changed, 40 insertions(+), 5 deletions(-) diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h index 8d1c8dcb87fd..97932fbf973d 100644 --- a/arch/arm64/include/asm/elf.h +++ b/arch/arm64/include/asm/elf.h @@ -213,10 +213,8 @@ typedef compat_elf_greg_t compat_elf_gregset_t[COMPAT_ELF_NGREG]; /* AArch32 EABI. */ #define EF_ARM_EABI_MASK 0xff000000 -#define compat_elf_check_arch(x) (system_supports_32bit_el0() && \ - ((x)->e_machine == EM_ARM) && \ - ((x)->e_flags & EF_ARM_EABI_MASK)) - +int compat_elf_check_arch(const struct elf32_hdr *); +#define compat_elf_check_arch compat_elf_check_arch #define compat_start_thread compat_start_thread /* * Unlike the native SET_PERSONALITY macro, the compat version maintains diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index c8989b999250..583ee58f8c9c 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -21,6 +21,7 @@ #include #include #include +#include #include #include #include @@ -579,6 +580,28 @@ unsigned long arch_align_stack(unsigned long sp) return sp & ~0xf; } +#ifdef CONFIG_COMPAT +int compat_elf_check_arch(const struct elf32_hdr *hdr) +{ + if (!system_supports_32bit_el0()) + return false; + + if ((hdr)->e_machine != EM_ARM) + return false; + + if (!((hdr)->e_flags & EF_ARM_EABI_MASK)) + return false; + + /* + * Prevent execve() of a 32-bit program from a deadline task + * if the restricted affinity mask would be inadmissible on an + * asymmetric system. + */ + return !static_branch_unlikely(&arm64_mismatched_32bit_el0) || + !dl_task_check_affinity(current, system_32bit_el0_cpumask()); +} +#endif + /* * Called from setup_new_exec() after (COMPAT_)SET_PERSONALITY. */ @@ -588,8 +611,22 @@ void arch_setup_new_exec(void) if (is_compat_task()) { mmflags = MMCF_AARCH32; - if (static_branch_unlikely(&arm64_mismatched_32bit_el0)) + + /* + * Restrict the CPU affinity mask for a 32-bit task so that + * it contains only 32-bit-capable CPUs. + * + * From the perspective of the task, this looks similar to + * what would happen if the 64-bit-only CPUs were hot-unplugged + * at the point of execve(), although we try a bit harder to + * honour the cpuset hierarchy. + */ + if (static_branch_unlikely(&arm64_mismatched_32bit_el0)) { + force_compatible_cpus_allowed_ptr(current); set_tsk_thread_flag(current, TIF_NOTIFY_RESUME); + } + } else if (static_branch_unlikely(&arm64_mismatched_32bit_el0)) { + relax_compatible_cpus_allowed_ptr(current); } current->mm->context.flags = mmflags;