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 C79EEC001E0 for ; Mon, 31 Jul 2023 15:16:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231888AbjGaPQt (ORCPT ); Mon, 31 Jul 2023 11:16:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38712 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231202AbjGaPQr (ORCPT ); Mon, 31 Jul 2023 11:16:47 -0400 Received: from cstnet.cn (smtp84.cstnet.cn [159.226.251.84]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 406851707; Mon, 31 Jul 2023 08:16:45 -0700 (PDT) Received: from [192.168.0.107] (unknown [111.197.209.91]) by APP-05 (Coremail) with SMTP id zQCowACnLeo+0MdkHM9REA--.17667S2; Mon, 31 Jul 2023 23:16:14 +0800 (CST) Message-ID: <90d97914-9576-42e7-0d7d-c752b5bd6a68@iscas.ac.cn> Date: Mon, 31 Jul 2023 23:16:14 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: [PATCH v3] riscv: Handle zicsr/zifencei issue between gcc and binutils Content-Language: en-US To: Conor Dooley Cc: Conor Dooley , Paul Walmsley , Palmer Dabbelt , Albert Ou , Nathan Chancellor , Nick Desaulniers , Tom Rix , Bin Meng , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, stable@vger.kernel.org, Guo Ren References: <20230731095936.23397-1-xingmingzheng@iscas.ac.cn> <20230731-calzone-gratified-dbc51639beec@wendy> From: Mingzheng Xing Organization: ISCAS In-Reply-To: <20230731-calzone-gratified-dbc51639beec@wendy> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CM-TRANSID: zQCowACnLeo+0MdkHM9REA--.17667S2 X-Coremail-Antispam: 1UD129KBjvJXoW3JF4fCw1kZr4UCFW8uFWDCFg_yoW3JF1Dpr W3CFyDCrs5Xa18G3WfJw1UX3WFvrs3G3yrKry5KryUu3sxCFyxKr9Yka13ZFyDZFnagw4F vw1xuFZY9w1DAaDanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUvCb7Iv0xC_Kw4lb4IE77IF4wAFF20E14v26r4j6ryUM7CY07I2 0VC2zVCF04k26cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rw A2F7IY1VAKz4vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Jr0_JF4l84ACjcxK6xII jxv20xvEc7CjxVAFwI0_Gr0_Cr1l84ACjcxK6I8E87Iv67AKxVW8Jr0_Cr1UM28EF7xvwV C2z280aVCY1x0267AKxVWxJr0_GcWle2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xv F2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_JrI_JrylYx0Ex4A2jsIE14v26r1j6r 4UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvEwIxGrwACI402YVCY1x02628vn2kIc2xK xwCYjI0SjxkI62AI1cAE67vIY487MxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r 1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CE b7AF67AKxVWUtVW8ZwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0x vE2Ix0cI8IcVCY1x0267AKxVW8JVWxJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAI cVC2z280aVAFwI0_Jr0_Gr1lIxAIcVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2Kf nxnUUI43ZEXa7IU5IksPUUUUU== X-Originating-IP: [111.197.209.91] X-CM-SenderInfo: 50lqwzhlqj6xxhqjqxpvfd2hldfou0/1tbiCQYJCmTHvCUmcAABsh Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/31/23 22:01, Conor Dooley wrote: > Hey, > > On Mon, Jul 31, 2023 at 05:59:36PM +0800, Mingzheng Xing wrote: >> Binutils-2.38 and GCC-12.1.0 bumped[0][1] the default ISA spec to the newer >> 20191213 version which moves some instructions from the I extension to the >> Zicsr and Zifencei extensions. So if one of the binutils and GCC exceeds >> that version, we should explicitly specifying Zicsr and Zifencei via -march >> to cope with the new changes. but this only occurs when binutils >= 2.36 >> and GCC >= 11.1.0. It's a different story when binutils < 2.36. >> >> binutils-2.36 supports the Zifencei extension[2] and splits Zifencei and >> Zicsr from I[3]. GCC-11.1.0 is particular[4] because it add support Zicsr >> and Zifencei extension for -march. binutils-2.35 does not support the >> Zifencei extension, and does not need to specify Zicsr and Zifencei when >> working with GCC >= 12.1.0. >> >> To make our lives easier, let's relax the check to binutils >= 2.36 in >> CONFIG_TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI. For the other two cases, >> where clang < 17 or GCC < 11.1.0, we will deal with them in >> CONFIG_TOOLCHAIN_NEEDS_OLD_ISA_SPEC. >> >> For more information, please refer to: >> commit 6df2a016c0c8 ("riscv: fix build with binutils 2.38") >> commit e89c2e815e76 ("riscv: Handle zicsr/zifencei issues between clang and binutils") >> Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=aed44286efa8ae8717a77d94b51ac3614e2ca6dc [0] >> Link: https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=98416dbb0a62579d4a7a4a76bab51b5b52fec2cd [1] >> Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=5a1b31e1e1cee6e9f1c92abff59cdcfff0dddf30 [2] >> Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=729a53530e86972d1143553a415db34e6e01d5d2 [3] >> Link: https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=b03be74bad08c382da47e048007a78fa3fb4ef49 [4] >> Link: https://lore.kernel.org/all/20230308220842.1231003-1-conor@kernel.org >> Link: https://lore.kernel.org/all/20230223220546.52879-1-conor@kernel.org >> Signed-off-by: Mingzheng Xing > You need to actually put the CC: stable@vger.kernel.org into the commit > message for the stable folks to pick things up. Thanks. Fixed in next version. >> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig >> index 4c07b9189c86..2704bd91dfb5 100644 >> --- a/arch/riscv/Kconfig >> +++ b/arch/riscv/Kconfig >> @@ -570,24 +570,31 @@ config TOOLCHAIN_HAS_ZIHINTPAUSE >> config TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI >> def_bool y >> # https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=aed44286efa8ae8717a77d94b51ac3614e2ca6dc >> - depends on AS_IS_GNU && AS_VERSION >= 23800 >> - help >> - Newer binutils versions default to ISA spec version 20191213 which >> - moves some instructions from the I extension to the Zicsr and Zifencei >> - extensions. >> + # https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=98416dbb0a62579d4a7a4a76bab51b5b52fec2cd >> + depends on AS_IS_GNU && AS_VERSION >= 23600 >> + help >> + Binutils-2.38 and GCC-12.1.0 bumped the default ISA spec to the newer >> + 20191213 version, which moves some instructions from the I extension to >> + the Zicsr and Zifencei extensions. This requires explicitly specifying >> + zicsr and zifencei when binutils >= 2.38 or GCC >= 12.1.0, >> but this only >> + occurs when binutils >= 2.36 and GCC >= 11.1.0. >> + It's a different story when binutils < 2.36. > I would replace this with something like: > Binutils-2.38 and GCC-12.1.0 bumped the default ISA spec to the newer > 20191213 version, which moves some instructions from the I extension to > the Zicsr and Zifencei extensions. This requires explicitly specifying > zicsr and zifencei when binutils >= 2.38 or GCC >= 12.1.0. Zicsr > and Zifencei are supported in binutils from version 2.36 onwards. > To make life easier, and avoid forcing toolchains that default to a > newer ISA spec to version 2.2, relax the check to binutils >= 2.36. > For clang < 17 or GCC < 11.1.0, for which this is not possible, this is > dealt with in CONFIG_TOOLCHAIN_NEEDS_OLD_ISA_SPEC. > > I tried to take the personification out of it & hopefully made it a > little clearer what dropping the check to 2.36 does for us. > >> Also, we have to consider the case of clang paired with binutils. > I think this sentence can go, its covered in the other config text. > > I'm sorry for being a bit of a pedant about this, but this has been such > a can of worms that I would like things to remain explained well enough > that the text is sufficient next time a revisit is required. Thanks for your review, I've made the changes and submitted a new PATCH but there seems to be an email thread issue, hopefully it won't have an effect, sorry about that. :) Thanks, Mingzheng. > > Thanks, > Conor. > >> + To make our lives easier, we relax the check to binutils >= 2.36. > >> config TOOLCHAIN_NEEDS_OLD_ISA_SPEC >> def_bool y >> depends on TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI >> # https://github.com/llvm/llvm-project/commit/22e199e6afb1263c943c0c0d4498694e15bf8a16 >> - depends on CC_IS_CLANG && CLANG_VERSION < 170000 >> - help >> - Certain versions of clang do not support zicsr and zifencei via -march >> - but newer versions of binutils require it for the reasons noted in the >> - help text of CONFIG_TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI. This >> - option causes an older ISA spec compatible with these older versions >> - of clang to be passed to GAS, which has the same result as passing zicsr >> - and zifencei to -march. >> + # https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=b03be74bad08c382da47e048007a78fa3fb4ef49 >> + depends on (CC_IS_CLANG && CLANG_VERSION < 170000) || (CC_IS_GCC && GCC_VERSION < 110100) >> + help >> + Certain versions of clang and GCC do not support zicsr and zifencei via >> + -march. This option causes an older ISA spec compatible with these older >> + versions of clang and GCC to be passed to GAS, which has the same result >> + as passing zicsr and zifencei to -march. >> >> config FPU >> bool "FPU support" >> diff --git a/arch/riscv/kernel/compat_vdso/Makefile b/arch/riscv/kernel/compat_vdso/Makefile >> index 189345773e7e..b86e5e2c3aea 100644 >> --- a/arch/riscv/kernel/compat_vdso/Makefile >> +++ b/arch/riscv/kernel/compat_vdso/Makefile >> @@ -11,7 +11,13 @@ compat_vdso-syms += flush_icache >> COMPAT_CC := $(CC) >> COMPAT_LD := $(LD) >> >> -COMPAT_CC_FLAGS := -march=rv32g -mabi=ilp32 >> +# binutils 2.35 does not support the zifencei extension, but in the ISA >> +# spec 20191213, G stands for IMAFD_ZICSR_ZIFENCEI. >> +ifdef CONFIG_TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI >> + COMPAT_CC_FLAGS := -march=rv32g -mabi=ilp32 >> +else >> + COMPAT_CC_FLAGS := -march=rv32imafd -mabi=ilp32 >> +endif >> COMPAT_LD_FLAGS := -melf32lriscv >> >> # Disable attributes, as they're useless and break the build. >> -- >> 2.34.1 >> >> >> _______________________________________________ >> linux-riscv mailing list >> linux-riscv@lists.infradead.org >> http://lists.infradead.org/mailman/listinfo/linux-riscv