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=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,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 21DC8C43331 for ; Fri, 27 Mar 2020 02:28:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F2723208E0 for ; Fri, 27 Mar 2020 02:28:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727806AbgC0C2l (ORCPT ); Thu, 26 Mar 2020 22:28:41 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:47830 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727666AbgC0C2k (ORCPT ); Thu, 26 Mar 2020 22:28:40 -0400 Received: from viro by ZenIV.linux.org.uk with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jHejd-003hFx-Qu; Fri, 27 Mar 2020 02:28:37 +0000 From: Al Viro To: Linus Torvalds Cc: Thomas Gleixner , x86@kernel.org, linux-kernel@vger.kernel.org Subject: [RFC][PATCH v2 5/8] x86: convert arch_futex_atomic_op_inuser() to user_access_begin/user_access_end() Date: Fri, 27 Mar 2020 02:28:33 +0000 Message-Id: <20200327022836.881203-5-viro@ZenIV.linux.org.uk> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200327022836.881203-1-viro@ZenIV.linux.org.uk> References: <20200327022836.881203-1-viro@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Al Viro Lift stac/clac pairs from __futex_atomic_op{1,2} into arch_futex_atomic_op_inuser(), fold them with access_ok() in there. The switch in arch_futex_atomic_op_inuser() is what has required the previous (objtool) commit... Signed-off-by: Al Viro --- arch/x86/include/asm/futex.h | 62 +++++++++++++++++++++++++------------------- 1 file changed, 36 insertions(+), 26 deletions(-) diff --git a/arch/x86/include/asm/futex.h b/arch/x86/include/asm/futex.h index 6bcd1c1486d9..53c07ab63762 100644 --- a/arch/x86/include/asm/futex.h +++ b/arch/x86/include/asm/futex.h @@ -12,26 +12,33 @@ #include #include -#define __futex_atomic_op1(insn, ret, oldval, uaddr, oparg) \ - asm volatile("\t" ASM_STAC "\n" \ - "1:\t" insn "\n" \ - "2:\t" ASM_CLAC "\n" \ +#define unsafe_atomic_op1(insn, oval, uaddr, oparg, label) \ +do { \ + int oldval = 0, ret; \ + asm volatile("1:\t" insn "\n" \ + "2:\n" \ "\t.section .fixup,\"ax\"\n" \ "3:\tmov\t%3, %1\n" \ "\tjmp\t2b\n" \ "\t.previous\n" \ _ASM_EXTABLE_UA(1b, 3b) \ : "=r" (oldval), "=r" (ret), "+m" (*uaddr) \ - : "i" (-EFAULT), "0" (oparg), "1" (0)) + : "i" (-EFAULT), "0" (oparg), "1" (0)); \ + if (ret) \ + goto label; \ + *oval = oldval; \ +} while(0) -#define __futex_atomic_op2(insn, ret, oldval, uaddr, oparg) \ - asm volatile("\t" ASM_STAC "\n" \ - "1:\tmovl %2, %0\n" \ + +#define unsafe_atomic_op2(insn, oval, uaddr, oparg, label) \ +do { \ + int oldval = 0, ret, tem; \ + asm volatile("1:\tmovl %2, %0\n" \ "\tmovl\t%0, %3\n" \ "\t" insn "\n" \ "2:\t" LOCK_PREFIX "cmpxchgl %3, %2\n" \ "\tjnz\t1b\n" \ - "3:\t" ASM_CLAC "\n" \ + "3:\n" \ "\t.section .fixup,\"ax\"\n" \ "4:\tmov\t%5, %1\n" \ "\tjmp\t3b\n" \ @@ -40,41 +47,44 @@ _ASM_EXTABLE_UA(2b, 4b) \ : "=&a" (oldval), "=&r" (ret), \ "+m" (*uaddr), "=&r" (tem) \ - : "r" (oparg), "i" (-EFAULT), "1" (0)) + : "r" (oparg), "i" (-EFAULT), "1" (0)); \ + if (ret) \ + goto label; \ + *oval = oldval; \ +} while(0) -static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval, +static __always_inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr) { - int oldval = 0, ret, tem; - - if (!access_ok(uaddr, sizeof(u32))) + if (!user_access_begin(uaddr, sizeof(u32))) return -EFAULT; switch (op) { case FUTEX_OP_SET: - __futex_atomic_op1("xchgl %0, %2", ret, oldval, uaddr, oparg); + unsafe_atomic_op1("xchgl %0, %2", oval, uaddr, oparg, Efault); break; case FUTEX_OP_ADD: - __futex_atomic_op1(LOCK_PREFIX "xaddl %0, %2", ret, oldval, - uaddr, oparg); + unsafe_atomic_op1(LOCK_PREFIX "xaddl %0, %2", oval, + uaddr, oparg, Efault); break; case FUTEX_OP_OR: - __futex_atomic_op2("orl %4, %3", ret, oldval, uaddr, oparg); + unsafe_atomic_op2("orl %4, %3", oval, uaddr, oparg, Efault); break; case FUTEX_OP_ANDN: - __futex_atomic_op2("andl %4, %3", ret, oldval, uaddr, ~oparg); + unsafe_atomic_op2("andl %4, %3", oval, uaddr, ~oparg, Efault); break; case FUTEX_OP_XOR: - __futex_atomic_op2("xorl %4, %3", ret, oldval, uaddr, oparg); + unsafe_atomic_op2("xorl %4, %3", oval, uaddr, oparg, Efault); break; default: - ret = -ENOSYS; + user_access_end(); + return -ENOSYS; } - - if (!ret) - *oval = oldval; - - return ret; + user_access_end(); + return 0; +Efault: + user_access_end(); + return -EFAULT; } static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, -- 2.11.0