From nobody Mon Sep 15 12:59:21 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 9DB17C61DB3 for ; Thu, 12 Jan 2023 09:12:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240074AbjALJMg (ORCPT ); Thu, 12 Jan 2023 04:12:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57290 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239939AbjALJKc (ORCPT ); Thu, 12 Jan 2023 04:10:32 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 37105517DE for ; Thu, 12 Jan 2023 01:06:26 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id C855961F9D for ; Thu, 12 Jan 2023 09:06:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1C022C43396; Thu, 12 Jan 2023 09:06:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1673514385; bh=903dKK56VBWA9nReoduRM1k/JbBxJj/M+VNo1IXCs18=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dkzjIZCYRCK6N2+ZVzl8WiNt48g3Hu2fgwRlh3Hbc4oMwg/noSl6WUDGeObO6ziYk k5ovFfyhTPYCSwMcUXEZqqY80xL49Jd//7LFlnPMoTCU/jdjE8jrbj5FUv/UDBz2qR I0SJiveKzzY/R0+MQB2iUzOyGEiCm32/UVLrOVqznPpcCkWM2WIGnEsjDqPBfIrnP5 cDq/bJeuuIFiiKR9InwSLXJW+w5HCfVlxg4ViTKbCXHbgaSB1hzKeEVP0i1riQ8Bap 4XibqqcbcZueSFAKpIS4MUrxJu3EgBE9uz5mo/M45fbq27LqtQZxQXElJLP34mzNou Ae/gY6/X2C3Sg== From: guoren@kernel.org To: anup@brainfault.org, paul.walmsley@sifive.com, palmer@dabbelt.com, conor.dooley@microchip.com, heiko@sntech.de, rostedt@goodmis.org, mhiramat@kernel.org, jolsa@redhat.com, bp@suse.de, jpoimboe@kernel.org, suagrfillet@gmail.com, andy.chiu@sifive.com, e.shatokhin@yadro.com, guoren@kernel.org Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Guo Ren Subject: [PATCH -next V7 2/7] riscv: ftrace: Remove wasted nops for !RISCV_ISA_C Date: Thu, 12 Jan 2023 04:05:58 -0500 Message-Id: <20230112090603.1295340-3-guoren@kernel.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20230112090603.1295340-1-guoren@kernel.org> References: <20230112090603.1295340-1-guoren@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Guo Ren When CONFIG_RISCV_ISA_C=3Dn, -fpatchable-function-entry=3D8 would generate more nops than we expect. Because it treat nop opcode as 0x00000013 instead of 0x0001. Dump of assembler code for function dw_pcie_free_msi: 0xffffffff806fce94 <+0>: sd ra,-8(sp) 0xffffffff806fce98 <+4>: auipc ra,0xff90f 0xffffffff806fce9c <+8>: jalr -684(ra) # 0xffffffff8000bbec 0xffffffff806fcea0 <+12>: ld ra,-8(sp) 0xffffffff806fcea4 <+16>: nop /* wasted */ 0xffffffff806fcea8 <+20>: nop /* wasted */ 0xffffffff806fceac <+24>: nop /* wasted */ 0xffffffff806fceb0 <+28>: nop /* wasted */ 0xffffffff806fceb4 <+0>: addi sp,sp,-48 0xffffffff806fceb8 <+4>: sd s0,32(sp) 0xffffffff806fcebc <+8>: sd s1,24(sp) 0xffffffff806fcec0 <+12>: sd s2,16(sp) 0xffffffff806fcec4 <+16>: sd s3,8(sp) 0xffffffff806fcec8 <+20>: sd ra,40(sp) 0xffffffff806fcecc <+24>: addi s0,sp,48 Signed-off-by: Guo Ren Signed-off-by: Guo Ren --- arch/riscv/Makefile | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile index 12d91b0a73d8..ea5a91da6897 100644 --- a/arch/riscv/Makefile +++ b/arch/riscv/Makefile @@ -11,7 +11,11 @@ LDFLAGS_vmlinux :=3D ifeq ($(CONFIG_DYNAMIC_FTRACE),y) LDFLAGS_vmlinux :=3D --no-relax KBUILD_CPPFLAGS +=3D -DCC_USING_PATCHABLE_FUNCTION_ENTRY +ifeq ($(CONFIG_RISCV_ISA_C),y) CC_FLAGS_FTRACE :=3D -fpatchable-function-entry=3D8 +else + CC_FLAGS_FTRACE :=3D -fpatchable-function-entry=3D4 +endif endif =20 ifeq ($(CONFIG_CMODEL_MEDLOW),y) --=20 2.36.1