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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 11B52C433F5 for ; Wed, 10 Nov 2021 10:17:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F147F60F9E for ; Wed, 10 Nov 2021 10:17:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231620AbhKJKT5 (ORCPT ); Wed, 10 Nov 2021 05:19:57 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40026 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231180AbhKJKTL (ORCPT ); Wed, 10 Nov 2021 05:19:11 -0500 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8A05DC061764 for ; Wed, 10 Nov 2021 02:16:23 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-ID:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=qxKK0eBcYTw0q3e0tzRJAm1lwOhw2KDVSjdm9BlgWhM=; b=rKZuQVheJQcVQPXl+L8x7Yvntg X63vwFh7UuxHXYm0nq4VCQwXB5EgT9/BGEOAlbqqbarNagcf9ihaB85rJ0NcL8DYfdmRwj4QFRWB8 cKnKcZDa8d0pdLNCWw0ixbSbOTyLbm/AyGk/SvWVSMMwZ0isV9/5BfdrOEuA2a2cOwVGZCy7tONIM SmC0Wjs65oGSh96sGvCSJtttpeOdjmp1ho6wKw7q1CVgn3CfrToe+4gDkqOFhE1aDObYQ39aD57J/ B9+Nz0AKrN+spuKz2b1dVvjtJq1KkeOa9UeySKmpiHe+41HAS2dD/3LT/khoj54l42uM8wilugOIk UbLZ6/qQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1mkkeH-00FFpn-7t; Wed, 10 Nov 2021 10:16:09 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id AFEAE301995; Wed, 10 Nov 2021 11:16:06 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 82439203E5607; Wed, 10 Nov 2021 11:16:06 +0100 (CET) Message-ID: <20211110101325.485154848@infradead.org> User-Agent: quilt/0.66 Date: Wed, 10 Nov 2021 11:01:12 +0100 From: Peter Zijlstra To: x86@kernel.org Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, jpoimboe@redhat.com, mark.rutland@arm.com, dvyukov@google.com, seanjc@google.com, pbonzini@redhat.com, mbenes@suse.cz Subject: [PATCH v2 10/23] x86,uaccess: Remove .fixup usage References: <20211110100102.250793167@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org For the !CC_AS_ASM_GOTO_OUTPUT (aka. the legacy codepath), remove the .fixup usage by employing both EX_TYPE_EFAULT_REG and EX_FLAG_CLEAR. Like was already done for X86_32's version of __get_user_asm_u64() use the "a" register for output, specifically so we can use CLEAR_AX. Signed-off-by: Peter Zijlstra (Intel) --- arch/x86/include/asm/uaccess.h | 39 +++++++++++++++++---------------------- 1 file changed, 17 insertions(+), 22 deletions(-) --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -351,24 +351,22 @@ do { \ "1: movl %[lowbits],%%eax\n" \ "2: movl %[highbits],%%edx\n" \ "3:\n" \ - ".section .fixup,\"ax\"\n" \ - "4: mov %[efault],%[errout]\n" \ - " xorl %%eax,%%eax\n" \ - " xorl %%edx,%%edx\n" \ - " jmp 3b\n" \ - ".previous\n" \ - _ASM_EXTABLE_UA(1b, 4b) \ - _ASM_EXTABLE_UA(2b, 4b) \ + _ASM_EXTABLE_TYPE_REG(1b, 3b, EX_TYPE_EFAULT_REG | \ + EX_FLAG_CLEAR_AX_DX, \ + %[errout]) \ + _ASM_EXTABLE_TYPE_REG(2b, 3b, EX_TYPE_EFAULT_REG | \ + EX_FLAG_CLEAR_AX_DX, \ + %[errout]) \ : [errout] "=r" (retval), \ [output] "=&A"(x) \ : [lowbits] "m" (__m(__ptr)), \ [highbits] "m" __m(((u32 __user *)(__ptr)) + 1), \ - [efault] "i" (-EFAULT), "0" (retval)); \ + "0" (retval)); \ }) #else #define __get_user_asm_u64(x, ptr, retval) \ - __get_user_asm(x, ptr, retval, "q", "=r") + __get_user_asm(x, ptr, retval, "q") #endif #define __get_user_size(x, ptr, size, retval) \ @@ -379,14 +377,14 @@ do { \ __chk_user_ptr(ptr); \ switch (size) { \ case 1: \ - __get_user_asm(x_u8__, ptr, retval, "b", "=q"); \ + __get_user_asm(x_u8__, ptr, retval, "b"); \ (x) = x_u8__; \ break; \ case 2: \ - __get_user_asm(x, ptr, retval, "w", "=r"); \ + __get_user_asm(x, ptr, retval, "w"); \ break; \ case 4: \ - __get_user_asm(x, ptr, retval, "l", "=r"); \ + __get_user_asm(x, ptr, retval, "l"); \ break; \ case 8: \ __get_user_asm_u64(x, ptr, retval); \ @@ -396,20 +394,17 @@ do { \ } \ } while (0) -#define __get_user_asm(x, addr, err, itype, ltype) \ +#define __get_user_asm(x, addr, err, itype) \ asm volatile("\n" \ "1: mov"itype" %[umem],%[output]\n" \ "2:\n" \ - ".section .fixup,\"ax\"\n" \ - "3: mov %[efault],%[errout]\n" \ - " xorl %k[output],%k[output]\n" \ - " jmp 2b\n" \ - ".previous\n" \ - _ASM_EXTABLE_UA(1b, 3b) \ + _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG | \ + EX_FLAG_CLEAR_AX, \ + %[errout]) \ : [errout] "=r" (err), \ - [output] ltype(x) \ + [output] "=a" (x) \ : [umem] "m" (__m(addr)), \ - [efault] "i" (-EFAULT), "0" (err)) + "0" (err)) #endif // CONFIG_CC_HAS_ASM_GOTO_OUTPUT