From patchwork Wed Jun 2 16:47:14 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 12295375 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=-17.4 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 646EFC47083 for ; Wed, 2 Jun 2021 16:57:14 +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 2EE5061C49 for ; Wed, 2 Jun 2021 16:57:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2EE5061C49 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@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=0fXwpY4T+qwdYkwIpdQuP8CqmxohiB9+G5uS0Ucastk=; b=n3V9QBVge1FRRB R+Y6QtJl5wiPOhCWkbEC2U8b3FNsdC1eWHDE2zPxhA9xZyqYc12lGTt09eS4OL+fz2vkz92reWa/x xYlq/V9hMB9RhZg7wrjjaa+3YOn8dbfJg/321LyGRmC5sO0/vQH2JaJQ3Ne7LYW6MC4psqqD5X9br wO2IxmJFUgTzHABN2bEYednW/2VZ5l4qkuFeDBci6dsccajpDwmFP0Q0TQctVaLmnBfzFJNdcv3Kg OftWSBOkp6JsmWnKZqxwfwOuBPRQmON7gqSrlWVHMA8AwLVYopxlJznU4UEnrGgN/poqDVxvtTdQ2 oXnxqGhgzP3fu654VXGw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1loU9J-005IZs-I0; Wed, 02 Jun 2021 16:55:22 +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 1loU2c-005FQO-GI for linux-arm-kernel@lists.infradead.org; Wed, 02 Jun 2021 16:48:28 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id C08CD61C21; Wed, 2 Jun 2021 16:48:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1622652506; bh=HrXZ0EwbWOBVx982EeAwxoN8NW7ueSeyfkaqXMfmBPY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=U6bsnPxKS9OIyF4eN1HvRBo7Lg5LUEiFWIJnKW3/rtnqLTOW4AxIEKzePXYWk5MNL uYarTxSpRj88dP4KtLNpoyjqzA47d2mzpGV/WPvRRP6jGevcVstGdHMKwBle46ctMu tA8Du6e+FTUkbcEbE4Yw7WFt01HSZbVviqxbTGBYpHKZldFnTPX+pteqsgfgD3eWku vK0M8HJbT36DcZ9ANUZnS4zwYA76h25n8Buv0fjLlK7STF7EQ3wOQOumtC/DiA6OC3 BshPOWJ9AgvnxpzUq+u6X3oF0YypiKLEWDXbUvQWJyZ6mZp+ISImpC+ekZ+ZxWCTEN vqzRskIIaNPjQ== 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 , kernel-team@android.com Subject: [PATCH v8 14/19] arm64: exec: Adjust affinity for compat tasks with mismatched 32-bit EL0 Date: Wed, 2 Jun 2021 17:47:14 +0100 Message-Id: <20210602164719.31777-15-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210602164719.31777-1-will@kernel.org> References: <20210602164719.31777-1-will@kernel.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210602_094826_638869_3C189743 X-CRM114-Status: GOOD ( 18.14 ) 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: Quentin Perret Signed-off-by: Will Deacon Reviewed-by: Daniel Bristot de Oliveira --- 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 f4a91bf1ce0c..3aea06fdd1f9 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include #include @@ -638,6 +639,28 @@ 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) || + task_cpus_dl_admissible(current, system_32bit_el0_cpumask()); +} +#endif + /* * Called from setup_new_exec() after (COMPAT_)SET_PERSONALITY. */ @@ -647,8 +670,22 @@ 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;