From nobody Thu Apr 2 21:50:50 2026 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 CC951C32771 for ; Wed, 21 Sep 2022 03:49:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230423AbiIUDtq (ORCPT ); Tue, 20 Sep 2022 23:49:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58446 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230146AbiIUDte (ORCPT ); Tue, 20 Sep 2022 23:49:34 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 073CFB21; Tue, 20 Sep 2022 20:49:30 -0700 (PDT) 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 98AA9627FB; Wed, 21 Sep 2022 03:49:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AE07BC43470; Wed, 21 Sep 2022 03:49:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1663732169; bh=XwVzwKWzSSnE5M8iQ5zKiH/uEZOA/qYNZrttzn2FPsQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=evMc6D5WdMFtNWHCWKTz6YKkVvfMfxzJr5PLOr8HVtcfVLSVGBMF+MZOilQrDAp/F QiEtDFUB4A10NFY/1eUChpXaNrY02KAuSHEkhfC5uJzyLQ5zIDgHMwJT3tRTXZHsxo oxCVrESLGPkfr+P55gY+71+ILubAtjpYbcgih0Srn3l8tJfz6W0gorxsxzdqUvNwZW mS208jHLqw3na33EBCEOnYAR904QYqH1QAzaJdJaygb2h05Lg/ZPHFLfR9uLpnZ/m7 PBYzptMQt1k3Ketlv9IgpPn6HuPpX+KCQ6Nj+L2D/0LCRY41piSM+0/8PcDzW9iy+c 8dMibz1MwLlng== From: guoren@kernel.org To: arnd@arndb.de, palmer@rivosinc.com, rostedt@goodmis.org, andy.chiu@sifive.com, greentime.hu@sifive.com, zong.li@sifive.com, jrtc27@jrtc27.com, mingo@redhat.com, palmer@dabbelt.com Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, guoren@kernel.org, Guo Ren Subject: [PATCH V2 2/3] riscv: ftrace: Remove wasted nops for !RISCV_ISA_C Date: Tue, 20 Sep 2022 23:49:09 -0400 Message-Id: <20220921034910.3142465-3-guoren@kernel.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220921034910.3142465-1-guoren@kernel.org> References: <20220921034910.3142465-1-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 3fa8ef336822..f32844f545d6 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