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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EEFA6ECAAD8 for ; Fri, 16 Sep 2022 10:54:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229863AbiIPKyu (ORCPT ); Fri, 16 Sep 2022 06:54:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53876 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231823AbiIPKyG (ORCPT ); Fri, 16 Sep 2022 06:54:06 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 517A9B0888; Fri, 16 Sep 2022 03:38:47 -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 ams.source.kernel.org (Postfix) with ESMTPS id CC7FDB825ED; Fri, 16 Sep 2022 10:38:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6FF95C433D7; Fri, 16 Sep 2022 10:38:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1663324724; bh=XwVzwKWzSSnE5M8iQ5zKiH/uEZOA/qYNZrttzn2FPsQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aTADtsZQRqUgZ8Fu8jhyGQlwDX+YFuhK7dKHvbytFm1kbh7Bz5o0AYIRQ1CKHpLaD dL+k/Zc4OXvMjhj3lrcRpHsA8JgicJFnT+sr/Z23qpp+sQgb9hbS3zcVk/AoFIT1RA scCeGOk6tHEeRUmM72HNnP7IZJscZ7b2CQyBxXGZsffoIHv/EOZExfNHRJFOcp0pVs EFr61FAgMYwXPS4pfEwiZoK8yuUpunq3JbepWzlKJi0RIDBWDIW4R1NLqO28p3vff2 x0/jz9yfNRaW6gOQd60rLeUXWGqFPbnrDUJ7DGGwJNfL/8iglchb7FccXYNG07aox9 FTAtQQ/lhxQBg== From: guoren@kernel.org To: arnd@arndb.de, guoren@kernel.org, palmer@rivosinc.com, rostedt@goodmis.org, andy.chiu@sifive.com, greentime.hu@sifive.com, zong.li@sifive.com, jrtc27@jrtc27.com, mingo@redhat.com Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, Guo Ren Subject: [PATCH 2/3] riscv: ftrace: Remove wasted nops for !RISCV_ISA_C Date: Fri, 16 Sep 2022 06:38:16 -0400 Message-Id: <20220916103817.9490-3-guoren@kernel.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220916103817.9490-1-guoren@kernel.org> References: <20220916103817.9490-1-guoren@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org From: Guo Ren When CONFIG_RISCV_ISA_C=n, -fpatchable-function-entry=8 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 := ifeq ($(CONFIG_DYNAMIC_FTRACE),y) LDFLAGS_vmlinux := --no-relax KBUILD_CPPFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY +ifeq ($(CONFIG_RISCV_ISA_C),y) CC_FLAGS_FTRACE := -fpatchable-function-entry=8 +else + CC_FLAGS_FTRACE := -fpatchable-function-entry=4 +endif endif ifeq ($(CONFIG_CMODEL_MEDLOW),y) -- 2.36.1