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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 D78BDC433E9 for ; Wed, 10 Mar 2021 17:48:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AEDA764F45 for ; Wed, 10 Mar 2021 17:48:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233689AbhCJRrh (ORCPT ); Wed, 10 Mar 2021 12:47:37 -0500 Received: from pegase1.c-s.fr ([93.17.236.30]:47673 "EHLO pegase1.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233570AbhCJRq4 (ORCPT ); Wed, 10 Mar 2021 12:46:56 -0500 Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 4Dwff54wDWz9tyv8; Wed, 10 Mar 2021 18:46:53 +0100 (CET) X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id 6YwoWykoiIDO; Wed, 10 Mar 2021 18:46:53 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 4Dwff53dhsz9tytH; Wed, 10 Mar 2021 18:46:53 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 4FBF78B78D; Wed, 10 Mar 2021 18:46:55 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id wiBXs09fYcDI; Wed, 10 Mar 2021 18:46:55 +0100 (CET) Received: from po16121vm.idsi0.si.c-s.fr (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 16F398B77E; Wed, 10 Mar 2021 18:46:55 +0100 (CET) Received: by po16121vm.idsi0.si.c-s.fr (Postfix, from userid 0) id E804E67568; Wed, 10 Mar 2021 17:46:54 +0000 (UTC) Message-Id: <403745b5aaa1b315bb4e8e46c1ba949e77eecec0.1615398265.git.christophe.leroy@csgroup.eu> In-Reply-To: References: From: Christophe Leroy Subject: [PATCH v2 15/15] powerpc/uaccess: Use asm goto for get_user when compiler supports it To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Date: Wed, 10 Mar 2021 17:46:54 +0000 (UTC) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org clang 11 and future GCC are supporting asm goto with outputs. Use it to implement get_user in order to get better generated code. Note that clang requires to set x in the default branch of __get_user_size_goto() otherwise is compliant about x not being initialised :puzzled: Signed-off-by: Christophe Leroy --- arch/powerpc/include/asm/uaccess.h | 55 ++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h index e3e53e88cb26..960ab5c04b11 100644 --- a/arch/powerpc/include/asm/uaccess.h +++ b/arch/powerpc/include/asm/uaccess.h @@ -136,6 +136,59 @@ do { \ : "=r" (err) \ : "b" (uaddr), "b" (kaddr), "i" (-EFAULT), "0" (err)) +#ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT + +#define __get_user_asm_goto(x, addr, label, op) \ + asm_volatile_goto( \ + "1: "op"%U1%X1 %0, %1 # get_user\n" \ + EX_TABLE(1b, %l2) \ + : "=r" (x) \ + : "m"UPD_CONSTR (*addr) \ + : \ + : label) + +#ifdef __powerpc64__ +#define __get_user_asm2_goto(x, addr, label) \ + __get_user_asm_goto(x, addr, label, "ld") +#else /* __powerpc64__ */ +#define __get_user_asm2_goto(x, addr, label) \ + asm_volatile_goto( \ + "1: lwz%X1 %0, %1\n" \ + "2: lwz%X1 %L0, %L1\n" \ + EX_TABLE(1b, %l2) \ + EX_TABLE(2b, %l2) \ + : "=r" (x) \ + : "m" (*addr) \ + : \ + : label) +#endif /* __powerpc64__ */ + +#define __get_user_size_goto(x, ptr, size, label) \ +do { \ + BUILD_BUG_ON(size > sizeof(x)); \ + switch (size) { \ + case 1: __get_user_asm_goto(x, (u8 __user *)ptr, label, "lbz"); break; \ + case 2: __get_user_asm_goto(x, (u16 __user *)ptr, label, "lhz"); break; \ + case 4: __get_user_asm_goto(x, (u32 __user *)ptr, label, "lwz"); break; \ + case 8: __get_user_asm2_goto(x, (u64 __user *)ptr, label); break; \ + default: x = 0; BUILD_BUG(); \ + } \ +} while (0) + +#define __get_user_size_allowed(x, ptr, size, retval) \ +do { \ + __label__ __gus_failed; \ + \ + __get_user_size_goto(x, ptr, size, __gus_failed); \ + retval = 0; \ + break; \ +__gus_failed: \ + x = 0; \ + retval = -EFAULT; \ +} while (0) + +#else /* CONFIG_CC_HAS_ASM_GOTO_OUTPUT */ + #define __get_user_asm(x, addr, err, op) \ __asm__ __volatile__( \ "1: "op"%U2%X2 %1, %2 # get_user\n" \ @@ -192,6 +245,8 @@ do { \ goto label; \ } while (0) +#endif /* CONFIG_CC_HAS_ASM_GOTO_OUTPUT */ + /* * This is a type: either unsigned long, if the argument fits into * that type, or otherwise unsigned long long. -- 2.25.0