From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AB15DBA45 for ; Tue, 7 Mar 2023 17:56:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 31B32C4339C; Tue, 7 Mar 2023 17:56:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1678211780; bh=voI6a9986FzORnmDyWvB195TsofQKYj/+HwWrXED/yY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TEUGEMzCLCxcFIcE1ZoIFbtvu/YpkWNDAFgxCECX2XBiuALaLxMlVKiP9jRe06bqO Su/2SNDzDyelqkp+oe+Nwft2imByb7urjP+mnv6FGp/KWemqspE+tB+WWb8WQf6Uaj F5Pag9fp5gViOAjVB0KKWHgN92SvCbBCwhJD9Pmk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Guo Ren , Guo Ren , Palmer Dabbelt Subject: [PATCH 6.2 0975/1001] riscv: ftrace: Remove wasted nops for !RISCV_ISA_C Date: Tue, 7 Mar 2023 18:02:27 +0100 Message-Id: <20230307170104.526654292@linuxfoundation.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230307170022.094103862@linuxfoundation.org> References: <20230307170022.094103862@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Guo Ren commit 409c8fb20c66df7150e592747412438c04aeb11f upstream. 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 Link: https://lore.kernel.org/r/20230112090603.1295340-3-guoren@kernel.org Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt Signed-off-by: Greg Kroah-Hartman --- arch/riscv/Makefile | 4 ++++ 1 file changed, 4 insertions(+) --- 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)