From patchwork Mon Dec 10 14:30:44 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vincenzo Frascino X-Patchwork-Id: 10721355 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0D60E13BF for ; Mon, 10 Dec 2018 14:31:42 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0090C2AA66 for ; Mon, 10 Dec 2018 14:31:42 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id F209D2AA9F; Mon, 10 Dec 2018 14:31:41 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 99E812AA66 for ; Mon, 10 Dec 2018 14:31:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727973AbeLJObf (ORCPT ); Mon, 10 Dec 2018 09:31:35 -0500 Received: from foss.arm.com ([217.140.101.70]:55240 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726791AbeLJObe (ORCPT ); Mon, 10 Dec 2018 09:31:34 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id ED6FB15AD; Mon, 10 Dec 2018 06:31:33 -0800 (PST) Received: from e119884-lin.cambridge.arm.com (e119884-lin.cambridge.arm.com [10.1.196.72]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 89F883F575; Mon, 10 Dec 2018 06:31:29 -0800 (PST) From: Vincenzo Frascino To: linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Catalin Marinas , Will Deacon , Mark Rutland , Robin Murphy , Kees Cook , Kate Stewart , Greg Kroah-Hartman , Andrew Morton , Ingo Molnar , "Kirill A . Shutemov" , Shuah Khan , Chintan Pandya , Jacob Bramley , Ruben Ayrapetyan , Andrey Konovalov , Lee Smith , Kostya Serebryany , Dmitry Vyukov , Ramana Radhakrishnan , Luc Van Oostenryck , Evgeniy Stepanov , Alexander Viro Subject: [RFC][PATCH 3/3] arm64: elf: Advertise relaxed ABI Date: Mon, 10 Dec 2018 14:30:44 +0000 Message-Id: <20181210143044.12714-4-vincenzo.frascino@arm.com> X-Mailer: git-send-email 2.19.2 In-Reply-To: <20181210143044.12714-1-vincenzo.frascino@arm.com> References: <20181210143044.12714-1-vincenzo.frascino@arm.com> MIME-Version: 1.0 Sender: linux-kselftest-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP On arm64 the TCR_EL1.TBI0 bit has been set since Linux 3.x hence the userspace (EL0) is allowed to set a non-zero value in the top byte but the resulting pointers are not allowed at the user-kernel syscall ABI boundary. This patch sets ARM64_AT_FLAGS_SYSCALL_TBI (bit[0]) in the AT_FLAGS to advertise the relaxation of the ABI to the userspace. Cc: Catalin Marinas Cc: Will Deacon CC: Andrey Konovalov Signed-off-by: Vincenzo Frascino --- arch/arm64/include/asm/atflags.h | 7 +++++++ arch/arm64/include/asm/elf.h | 5 +++++ arch/arm64/include/uapi/asm/atflags.h | 8 ++++++++ 3 files changed, 20 insertions(+) create mode 100644 arch/arm64/include/asm/atflags.h create mode 100644 arch/arm64/include/uapi/asm/atflags.h diff --git a/arch/arm64/include/asm/atflags.h b/arch/arm64/include/asm/atflags.h new file mode 100644 index 000000000000..b20093d61bf2 --- /dev/null +++ b/arch/arm64/include/asm/atflags.h @@ -0,0 +1,7 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_ATFLAGS_H +#define __ASM_ATFLAGS_H + +#include + +#endif diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h index 433b9554c6a1..da5a6d310ff4 100644 --- a/arch/arm64/include/asm/elf.h +++ b/arch/arm64/include/asm/elf.h @@ -16,6 +16,7 @@ #ifndef __ASM_ELF_H #define __ASM_ELF_H +#include #include /* @@ -163,6 +164,10 @@ do { \ NEW_AUX_ENT(AT_IGNORE, 0); \ } while (0) +/* Platform specific AT_FLAGS */ +#define ELF_AT_FLAGS ARM64_AT_FLAGS_SYSCALL_TBI +#define COMPAT_ELF_AT_FLAGS 0 + #define ARCH_HAS_SETUP_ADDITIONAL_PAGES struct linux_binprm; extern int arch_setup_additional_pages(struct linux_binprm *bprm, diff --git a/arch/arm64/include/uapi/asm/atflags.h b/arch/arm64/include/uapi/asm/atflags.h new file mode 100644 index 000000000000..1cf25692ffd6 --- /dev/null +++ b/arch/arm64/include/uapi/asm/atflags.h @@ -0,0 +1,8 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __UAPI_ASM_ATFLAGS_H +#define __UAPI_ASM_ATFLAGS_H + +/* Platform specific AT_FLAGS */ +#define ARM64_AT_FLAGS_SYSCALL_TBI (1 << 0) + +#endif