From mboxrd@z Thu Jan 1 00:00:00 1970 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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 37D1DC282CD for ; Mon, 28 Jan 2019 06:59:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 11ACE21736 for ; Mon, 28 Jan 2019 06:59:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726825AbfA1G7T (ORCPT ); Mon, 28 Jan 2019 01:59:19 -0500 Received: from foss.arm.com ([217.140.101.70]:39828 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726612AbfA1G7S (ORCPT ); Mon, 28 Jan 2019 01:59:18 -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 CDF731596; Sun, 27 Jan 2019 22:59:17 -0800 (PST) Received: from a075553-lin.blr.arm.com (a075553-lin.blr.arm.com [10.162.0.39]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 199BF3F5AF; Sun, 27 Jan 2019 22:59:13 -0800 (PST) From: Amit Daniel Kachhap To: linux-arm-kernel@lists.infradead.org Cc: Christoffer Dall , Marc Zyngier , Catalin Marinas , Will Deacon , Andrew Jones , Dave Martin , Ramana Radhakrishnan , kvmarm@lists.cs.columbia.edu, Kristina Martsenko , linux-kernel@vger.kernel.org, Amit Daniel Kachhap , Mark Rutland Subject: [PATCH v5 1/5] arm64: Add utilities to save restore pointer authentication keys Date: Mon, 28 Jan 2019 12:28:42 +0530 Message-Id: <1548658727-14271-2-git-send-email-amit.kachhap@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1548658727-14271-1-git-send-email-amit.kachhap@arm.com> References: <1548658727-14271-1-git-send-email-amit.kachhap@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The keys can be switched either inside an assembly or such functions which do not have pointer authentication checks, so a GCC attribute is added to enable it. A function ptrauth_keys_store is added which is similar to existing function ptrauth_keys_switch but saves the key values in memory. This may be useful for save/restore scenarios when CPU changes privilege levels, suspend/resume etc. Signed-off-by: Amit Daniel Kachhap Cc: Mark Rutland Cc: Marc Zyngier Cc: Christoffer Dall Cc: Kristina Martsenko Cc: kvmarm@lists.cs.columbia.edu Cc: Ramana Radhakrishnan Cc: Will Deacon --- arch/arm64/include/asm/pointer_auth.h | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/arch/arm64/include/asm/pointer_auth.h b/arch/arm64/include/asm/pointer_auth.h index 15d4951..98441ce 100644 --- a/arch/arm64/include/asm/pointer_auth.h +++ b/arch/arm64/include/asm/pointer_auth.h @@ -11,6 +11,13 @@ #ifdef CONFIG_ARM64_PTR_AUTH /* + * Compile the function without pointer authentication instructions. This + * allows pointer authentication to be enabled/disabled within the function + * (but leaves the function unprotected by pointer authentication). + */ +#define __no_ptrauth __attribute__((target("sign-return-address=none"))) + +/* * Each key is a 128-bit quantity which is split across a pair of 64-bit * registers (Lo and Hi). */ @@ -50,6 +57,13 @@ do { \ write_sysreg_s(__pki_v.hi, SYS_ ## k ## KEYHI_EL1); \ } while (0) +#define __ptrauth_key_save(k, v) \ +do { \ + struct ptrauth_key __pki_v = (v); \ + __pki_v.lo = read_sysreg_s(SYS_ ## k ## KEYLO_EL1); \ + __pki_v.hi = read_sysreg_s(SYS_ ## k ## KEYHI_EL1); \ +} while (0) + static inline void ptrauth_keys_switch(struct ptrauth_keys *keys) { if (system_supports_address_auth()) { @@ -63,6 +77,19 @@ static inline void ptrauth_keys_switch(struct ptrauth_keys *keys) __ptrauth_key_install(APGA, keys->apga); } +static inline void ptrauth_keys_store(struct ptrauth_keys *keys) +{ + if (system_supports_address_auth()) { + __ptrauth_key_save(APIA, keys->apia); + __ptrauth_key_save(APIB, keys->apib); + __ptrauth_key_save(APDA, keys->apda); + __ptrauth_key_save(APDB, keys->apdb); + } + + if (system_supports_generic_auth()) + __ptrauth_key_save(APGA, keys->apga); +} + extern int ptrauth_prctl_reset_keys(struct task_struct *tsk, unsigned long arg); /* @@ -88,6 +115,7 @@ do { \ ptrauth_keys_switch(&(tsk)->thread.keys_user) #else /* CONFIG_ARM64_PTR_AUTH */ +#define __no_ptrauth #define ptrauth_prctl_reset_keys(tsk, arg) (-EINVAL) #define ptrauth_strip_insn_pac(lr) (lr) #define ptrauth_thread_init_user(tsk) -- 2.7.4