From nobody Fri Dec 19 06:34:59 2025 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6BBA8C001DC for ; Wed, 26 Jul 2023 07:55:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232285AbjGZHzd (ORCPT ); Wed, 26 Jul 2023 03:55:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44786 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232166AbjGZHzB (ORCPT ); Wed, 26 Jul 2023 03:55:01 -0400 Received: from m12.mail.163.com (m12.mail.163.com [220.181.12.197]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 0445A2716 for ; Wed, 26 Jul 2023 00:48:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id:MIME-Version; bh=XBOiX PX2QzyY0i5nmgALbzYaYDYC6Y2vfucDHylj3v8=; b=nSlpnmCXTfGja3eME4Ebv v56CrtjXNrup3/HNyFGn/pH38jYW6wWyb4WstVvuBkX+aMNi/wE0F22ml5X5vQfi QZ89cTzLazNVHnQoXDt3DPTTapDoA1MAMoMMs8NCnApOOs5LPo7QgN6ORhR1h+XR dRlIXVMj4hsgX8gjiENBKM= Received: from yw-virtual-machine.localdomain (unknown [180.110.115.47]) by zwqz-smtp-mta-g2-4 (Coremail) with SMTP id _____wA33FiWz8BkpmpnBQ--.9036S2; Wed, 26 Jul 2023 15:47:35 +0800 (CST) From: wang_yang To: palmer@dabbelt.com Cc: aou@eecs.berkeley.edu, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, wang_yang , Wang Yang Subject: [PATCH] RISC-V: Use GCC __builtin_prefetch() to implement prefetch() Date: Wed, 26 Jul 2023 15:47:32 +0800 Message-Id: <20230726074732.32981-1-wang_yang6662023@163.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: _____wA33FiWz8BkpmpnBQ--.9036S2 X-Coremail-Antispam: 1Uf129KBjvJXoW7Kr4xXryfJw1rGF18ury8Zrb_yoW8GFWxpF Z5Crn3WrWrWF1xu3yfJF4kWa1rKrnYgr4avrWxKwn7XFsxAr97tr9akrs8Jrn8JFWrZ34S yFW2qryrXa15AaDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0zRIeHkUUUUU= X-Originating-IP: [180.110.115.47] X-CM-SenderInfo: 5zdqwsp1dqwlawwsijqt6rljoofrz/1S2mbAG49WNftPdKWwABsP Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" GCC's __builtin_prefetch() was introduced a long time ago, all supported G= CC versions have it.So this patch is to use it for implementing the prefetch. RISC-V Cache Management Operation instructions has been supported by GCC l= ast year.you can refer to https://github.com/gcc-mirror/gcc/commit/3df3ca9014f94fe4af07444fea19b4ab2= 9ba8e73 It is worth noting that CPU based on RISC-V should support Zicbop extensio= n. This has been already done on other architectures (see the commit: https://github.com/torvalds/linux/commit/0453fb3c528c5eb3483441a466b24a4cb= 409eec5). Signed-off-by: Wang Yang --- arch/riscv/include/asm/processor.h | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/pr= ocessor.h index c950a8d9edef..f16d4c85ca5b 100644 --- a/arch/riscv/include/asm/processor.h +++ b/arch/riscv/include/asm/processor.h @@ -70,6 +70,17 @@ extern void start_thread(struct pt_regs *regs, =20 extern unsigned long __get_wchan(struct task_struct *p); =20 +#define ARCH_HAS_PREFETCH +static inline void prefetch(const void *ptr) +{ + __builtin_prefetch(ptr, 0, 3); +} + +#define ARCH_HAS_PREFETCHW +static inline void prefetchw(const void *ptr) +{ + __builtin_prefetch(ptr, 1, 3); +} =20 static inline void wait_for_interrupt(void) { --=20 2.34.1