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,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 DB791C04EBF for ; Mon, 3 Dec 2018 13:55:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A2780206B7 for ; Mon, 3 Dec 2018 13:55:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A2780206B7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726565AbeLCN4h (ORCPT ); Mon, 3 Dec 2018 08:56:37 -0500 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:37862 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725830AbeLCN4g (ORCPT ); Mon, 3 Dec 2018 08:56:36 -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 58CD2169E; Mon, 3 Dec 2018 05:55:29 -0800 (PST) Received: from e112298-lin.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id D32993F614; Mon, 3 Dec 2018 05:55:27 -0800 (PST) From: Julien Thierry To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: mingo@redhat.com, peterz@infradead.org, catalin.marinas@arm.com, will.deacon@arm.com, james.morse@arm.com, hpa@zytor.com, Julien Thierry Subject: [PATCH v2 2/2] arm64: uaccess: Implement unsafe accessors Date: Mon, 3 Dec 2018 13:55:18 +0000 Message-Id: <1543845318-24543-3-git-send-email-julien.thierry@arm.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1543845318-24543-1-git-send-email-julien.thierry@arm.com> References: <1543845318-24543-1-git-send-email-julien.thierry@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Current implementation of get/put_user_unsafe default to get/put_user which toggle PAN before each access, despite having been told by the caller that multiple accesses to user memory were about to happen. Provide implementations for user_access_begin/end to turn PAN off/on and implement unsafe accessors that assume PAN was already turned off. Signed-off-by: Julien Thierry --- arch/arm64/include/asm/sysreg.h | 2 + arch/arm64/include/asm/uaccess.h | 89 +++++++++++++++++++++++++++++++--------- 2 files changed, 71 insertions(+), 20 deletions(-) diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h index 842fb95..4e6477b 100644 --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -108,6 +108,8 @@ #define SYS_DC_CSW sys_insn(1, 0, 7, 10, 2) #define SYS_DC_CISW sys_insn(1, 0, 7, 14, 2) +#define SYS_PSTATE_PAN sys_reg(3, 0, 4, 2, 3) + #define SYS_OSDTRRX_EL1 sys_reg(2, 0, 0, 0, 2) #define SYS_MDCCINT_EL1 sys_reg(2, 0, 0, 2, 0) #define SYS_MDSCR_EL1 sys_reg(2, 0, 0, 2, 2) diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index 07c3408..cabfcae 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -233,6 +233,23 @@ static inline void uaccess_enable_not_uao(void) __uaccess_enable(ARM64_ALT_PAN_NOT_UAO); } +#define unsafe_user_region_active uaccess_region_active +static inline bool uaccess_region_active(void) +{ + if (system_uses_ttbr0_pan()) { + u64 ttbr; + + ttbr = read_sysreg(ttbr1_el1); + return ttbr & TTBR_ASID_MASK; + } else if (cpus_have_const_cap(ARM64_ALT_PAN_NOT_UAO)) { + return (read_sysreg(sctlr_el1) & SCTLR_EL1_SPAN) ? + false : + !read_sysreg_s(SYS_PSTATE_PAN); + } + + return false; +} + /* * Sanitise a uaccess pointer such that it becomes NULL if above the * current addr_limit. @@ -276,11 +293,9 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr) : "+r" (err), "=&r" (x) \ : "r" (addr), "i" (-EFAULT)) -#define __get_user_err(x, ptr, err) \ +#define __get_user_err_unsafe(x, ptr, err) \ do { \ unsigned long __gu_val; \ - __chk_user_ptr(ptr); \ - uaccess_enable_not_uao(); \ switch (sizeof(*(ptr))) { \ case 1: \ __get_user_asm("ldrb", "ldtrb", "%w", __gu_val, (ptr), \ @@ -301,17 +316,26 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr) default: \ BUILD_BUG(); \ } \ - uaccess_disable_not_uao(); \ (x) = (__force __typeof__(*(ptr)))__gu_val; \ } while (0) -#define __get_user_check(x, ptr, err) \ +#define __get_user_err_check(x, ptr, err) \ +do { \ + __typeof__(x) __gu_dest; \ + __chk_user_ptr(ptr); \ + uaccess_enable_not_uao(); \ + __get_user_err_unsafe((__gu_dest), (ptr), (err)); \ + uaccess_disable_not_uao(); \ + (x) = __gu_dest; \ +} while (0) + +#define __get_user_err(x, ptr, err, accessor) \ ({ \ __typeof__(*(ptr)) __user *__p = (ptr); \ might_fault(); \ if (access_ok(VERIFY_READ, __p, sizeof(*__p))) { \ __p = uaccess_mask_ptr(__p); \ - __get_user_err((x), __p, (err)); \ + accessor((x), __p, (err)); \ } else { \ (x) = 0; (err) = -EFAULT; \ } \ @@ -319,14 +343,14 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr) #define __get_user_error(x, ptr, err) \ ({ \ - __get_user_check((x), (ptr), (err)); \ + __get_user_err((x), (ptr), (err), __get_user_err_check); \ (void)0; \ }) #define __get_user(x, ptr) \ ({ \ int __gu_err = 0; \ - __get_user_check((x), (ptr), __gu_err); \ + __get_user_err((x), (ptr), __gu_err, __get_user_err_check); \ __gu_err; \ }) @@ -346,41 +370,46 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr) : "+r" (err) \ : "r" (x), "r" (addr), "i" (-EFAULT)) -#define __put_user_err(x, ptr, err) \ +#define __put_user_err_unsafe(x, ptr, err) \ do { \ - __typeof__(*(ptr)) __pu_val = (x); \ - __chk_user_ptr(ptr); \ - uaccess_enable_not_uao(); \ switch (sizeof(*(ptr))) { \ case 1: \ - __put_user_asm("strb", "sttrb", "%w", __pu_val, (ptr), \ + __put_user_asm("strb", "sttrb", "%w", (x), (ptr), \ (err), ARM64_HAS_UAO); \ break; \ case 2: \ - __put_user_asm("strh", "sttrh", "%w", __pu_val, (ptr), \ + __put_user_asm("strh", "sttrh", "%w", (x), (ptr), \ (err), ARM64_HAS_UAO); \ break; \ case 4: \ - __put_user_asm("str", "sttr", "%w", __pu_val, (ptr), \ + __put_user_asm("str", "sttr", "%w", (x), (ptr), \ (err), ARM64_HAS_UAO); \ break; \ case 8: \ - __put_user_asm("str", "sttr", "%x", __pu_val, (ptr), \ + __put_user_asm("str", "sttr", "%x", (x), (ptr), \ (err), ARM64_HAS_UAO); \ break; \ default: \ BUILD_BUG(); \ } \ +} while (0) + +#define __put_user_err_check(x, ptr, err) \ +do { \ + __typeof__(*(ptr)) __pu_val = (x); \ + __chk_user_ptr(ptr); \ + uaccess_enable_not_uao(); \ + __put_user_err_unsafe(__pu_val, (ptr), (err)); \ uaccess_disable_not_uao(); \ } while (0) -#define __put_user_check(x, ptr, err) \ +#define __put_user_err(x, ptr, err, accessor) \ ({ \ __typeof__(*(ptr)) __user *__p = (ptr); \ might_fault(); \ if (access_ok(VERIFY_WRITE, __p, sizeof(*__p))) { \ __p = uaccess_mask_ptr(__p); \ - __put_user_err((x), __p, (err)); \ + accessor((x), __p, (err)); \ } else { \ (err) = -EFAULT; \ } \ @@ -388,19 +417,39 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr) #define __put_user_error(x, ptr, err) \ ({ \ - __put_user_check((x), (ptr), (err)); \ + __put_user_err((x), (ptr), (err), __put_user_err_check); \ (void)0; \ }) #define __put_user(x, ptr) \ ({ \ int __pu_err = 0; \ - __put_user_check((x), (ptr), __pu_err); \ + __put_user_err((x), (ptr), __pu_err, __put_user_err_check); \ __pu_err; \ }) #define put_user __put_user + +#define user_access_begin() uaccess_enable_not_uao() +#define user_access_end() uaccess_disable_not_uao() + +#define unsafe_get_user(x, ptr, err) \ +do { \ + int __gu_err = 0; \ + __get_user_err((x), (ptr), __gu_err, __get_user_err_unsafe); \ + if (__gu_err != 0) \ + goto err; \ +} while (0) + +#define unsafe_put_user(x, ptr, err) \ +do { \ + int __pu_err = 0; \ + __put_user_err((x), (ptr), __pu_err, __put_user_err_unsafe); \ + if (__pu_err != 0) \ + goto err; \ +} while (0) + extern unsigned long __must_check __arch_copy_from_user(void *to, const void __user *from, unsigned long n); #define raw_copy_from_user(to, from, n) \ ({ \ -- 1.9.1