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 32902C43219 for ; Mon, 14 Nov 2022 12:51:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237323AbiKNMve (ORCPT ); Mon, 14 Nov 2022 07:51:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44218 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237395AbiKNMvd (ORCPT ); Mon, 14 Nov 2022 07:51:33 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DC96A24BCF for ; Mon, 14 Nov 2022 04:51:32 -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 7A05161154 for ; Mon, 14 Nov 2022 12:51:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 83D8AC433C1; Mon, 14 Nov 2022 12:51:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1668430291; bh=5INxvdkrZdnoPpZuTkuR+uGXSLOmk4YkqYJqDnOu7/c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=J8sqkv/l1/n0DbdHsbuhqZBPHoFuL/2k8nZAee4pRK/r3SaJeeWH7CV/m7C/Te8Ad f9gSXHmFUcPgnEOqhlsvUJOimS3Ch9i2KzLJV9qUvQPuR0yg+lJOOW/MUeCaNabD4m RkZSbmBdyDKWIj5RWKCP+klzZNF2SXsvfuz4lKZc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jisheng Zhang , Conor Dooley , Palmer Dabbelt , Sasha Levin Subject: [PATCH 5.10 51/95] riscv: vdso: fix build with llvm Date: Mon, 14 Nov 2022 13:45:45 +0100 Message-Id: <20221114124444.653333184@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221114124442.530286937@linuxfoundation.org> References: <20221114124442.530286937@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jisheng Zhang [ Upstream commit 50f4dd657a0fcf90aa8da8dc2794a8100ff4c37c ] Even after commit 89fd4a1df829 ("riscv: jump_label: mark arguments as const to satisfy asm constraints"), building with CC_OPTIMIZE_FOR_SIZE + LLVM=1 can reproduce below build error: CC arch/riscv/kernel/vdso/vgettimeofday.o In file included from :4: In file included from lib/vdso/gettimeofday.c:5: In file included from include/vdso/datapage.h:17: In file included from include/vdso/processor.h:10: In file included from arch/riscv/include/asm/vdso/processor.h:7: In file included from include/linux/jump_label.h:112: arch/riscv/include/asm/jump_label.h:42:3: error: invalid operand for inline asm constraint 'i' " .option push \n\t" ^ 1 error generated. I think the problem is when "-Os" is passed as CFLAGS, it's removed by "CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os" which is introduced in commit e05d57dcb8c7 ("riscv: Fixup __vdso_gettimeofday broke dynamic ftrace"), thus no optimization at all for vgettimeofday.c arm64 does remove "-Os" as well, but it forces "-O2" after removing "-Os". I compared the generated vgettimeofday.o with "-O2" and "-Os", I think no big performance difference. So let's tell the kbuild not to remove "-Os" rather than follow arm64 style. vdso related performance can be improved a lot when building kernel with CC_OPTIMIZE_FOR_SIZE after this commit, ("-Os" VS no optimization) Fixes: e05d57dcb8c7 ("riscv: Fixup __vdso_gettimeofday broke dynamic ftrace") Signed-off-by: Jisheng Zhang Tested-by: Conor Dooley Link: https://lore.kernel.org/r/20221031182943.2453-1-jszhang@kernel.org Signed-off-by: Palmer Dabbelt Signed-off-by: Sasha Levin --- arch/riscv/kernel/vdso/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile index 24d936c147cd..926ab3960f9e 100644 --- a/arch/riscv/kernel/vdso/Makefile +++ b/arch/riscv/kernel/vdso/Makefile @@ -30,7 +30,7 @@ obj-y += vdso.o vdso-syms.o CPPFLAGS_vdso.lds += -P -C -U$(ARCH) # Disable -pg to prevent insert call site -CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os +CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) # Disable profiling and instrumentation for VDSO code GCOV_PROFILE := n -- 2.35.1