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 98DC07E for ; Sat, 8 Oct 2022 14:04:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2E921C433D6; Sat, 8 Oct 2022 14:04:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1665237885; bh=GOGHwqAqL5S8D2cBZguxt8zHGahgZPhATTi6qcess1M=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pTTSZv1OF1epBnqirqFQfeU9NrnMEBbu7bvRWQpc6mLkbEnOl7AErepvl2sxZPpF8 Sl+MYeiLKnYntW1woVs0BnVZrDI/NMx4+qmaGjM0b/rV6xZsTKJ/VzWDCyn97qGyqh cNpEeNIEVYbLmQ5ChCZaZOLnLn1XiE1QmjKNS70rXkDw82VXX0veD9gsjc8dw1ofws 6y3jsHRy0izLxlwAL0wNNx7AiNjvMUal40NdXIQROD4fjtNXSemF/tvJzPP2VKqX0F 17dJwDWzayPMDlkwIiCa4+BmrhmDozjVoCkXcueLbMdeL1Z3eNryrTEhnCjeyD+QUg LW4hlt3ZM4pYA== Date: Sat, 8 Oct 2022 21:55:07 +0800 From: Jisheng Zhang To: Conor.Dooley@microchip.com Cc: peterz@infradead.org, jpoimboe@kernel.org, jbaron@akamai.com, rostedt@goodmis.org, ajones@ventanamicro.com, ardb@kernel.org, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, nathan@kernel.org, ndesaulniers@google.com, trix@redhat.com, samuel@sholland.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev Subject: Re: [PATCH] riscv: jump_label: mark arguments as const to satisfy asm constraints Message-ID: References: <20221006064028.548-1-jszhang@kernel.org> <20221006124144.abaz74g7nxrb5hxj@kamzik> <4c8fa16a-8463-ee32-7307-0383fa94403c@microchip.com> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <4c8fa16a-8463-ee32-7307-0383fa94403c@microchip.com> On Thu, Oct 06, 2022 at 12:44:32PM +0000, Conor.Dooley@microchip.com wrote: > On 06/10/2022 13:41, Andrew Jones wrote: > > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > > > > On Thu, Oct 06, 2022 at 02:40:28PM +0800, Jisheng Zhang wrote: > >> Samuel reported that the static branch usage in cpu_relax() breaks > >> building with CONFIG_CC_OPTIMIZE_FOR_SIZE[1]: > >> > >> In file included from : > >> ./arch/riscv/include/asm/jump_label.h: In function 'cpu_relax': > >> ././include/linux/compiler_types.h:285:33: warning: 'asm' operand 0 > >> probably does not match constraints > >> 285 | #define asm_volatile_goto(x...) asm goto(x) > >> | ^~~ > >> ./arch/riscv/include/asm/jump_label.h:41:9: note: in expansion of macro > >> 'asm_volatile_goto' > >> 41 | asm_volatile_goto( > >> | ^~~~~~~~~~~~~~~~~ > >> ././include/linux/compiler_types.h:285:33: error: impossible constraint > >> in 'asm' > >> 285 | #define asm_volatile_goto(x...) asm goto(x) > >> | ^~~ > >> ./arch/riscv/include/asm/jump_label.h:41:9: note: in expansion of macro > >> 'asm_volatile_goto' > >> 41 | asm_volatile_goto( > >> | ^~~~~~~~~~~~~~~~~ > >> make[1]: *** [scripts/Makefile.build:249: > >> arch/riscv/kernel/vdso/vgettimeofday.o] Error 1 > >> make: *** [arch/riscv/Makefile:128: vdso_prepare] Error 2 > >> > >> Maybe "-Os" prevents GCC from detecting that the key/branch arguments > >> can be treated as constants and used as immediate operands. Inspired > >> by x86's commit 864b435514b2("x86/jump_label: Mark arguments as const to > >> satisfy asm constraints"), and as pointed out by Steven in [2] "The "i" > >> constraint needs to be a constant.", let's do similar modifications to > >> riscv. > >> > >> Tested by CC_OPTIMIZE_FOR_SIZE + gcc and CC_OPTIMIZE_FOR_SIZE + clang. > >> > >> [1]https://lore.kernel.org/linux-riscv/20220922060958.44203-1-samuel@sholland.org/ > >> [2]https://lore.kernel.org/all/20210212094059.5f8d05e8@gandalf.local.home/ > > Hey Jisheng, Hi, > > Could you please make these normal link tags.? How to make these link tags? I just used the permalink in lore.kernel.org > Also could you please add the reported-by from samuel & a fixes tag? I will add Reported-by tag, but I'm not sure whether fixes tag is suitable, and which commit I could use? commit 8eb060e1018 ("arch/riscv: add Zihintpause support")? > > Thanks, > Conor. > > >> Signed-off-by: Jisheng Zhang > >> --- > >> arch/riscv/include/asm/jump_label.h | 8 ++++---- > >> 1 file changed, 4 insertions(+), 4 deletions(-) > >> > >> diff --git a/arch/riscv/include/asm/jump_label.h b/arch/riscv/include/asm/jump_label.h > >> index 38af2ec7b9bf..6d58bbb5da46 100644 > >> --- a/arch/riscv/include/asm/jump_label.h > >> +++ b/arch/riscv/include/asm/jump_label.h > >> @@ -14,8 +14,8 @@ > >> > >> #define JUMP_LABEL_NOP_SIZE 4 > >> > >> -static __always_inline bool arch_static_branch(struct static_key *key, > >> - bool branch) > >> +static __always_inline bool arch_static_branch(struct static_key * const key, > >> + const bool branch) > >> { > >> asm_volatile_goto( > >> " .option push \n\t" > >> @@ -35,8 +35,8 @@ static __always_inline bool arch_static_branch(struct static_key *key, > >> return true; > >> } > >> > >> -static __always_inline bool arch_static_branch_jump(struct static_key *key, > >> - bool branch) > >> +static __always_inline bool arch_static_branch_jump(struct static_key * const key, > >> + const bool branch) > >> { > >> asm_volatile_goto( > >> " .option push \n\t" > >> -- > >> 2.37.2 > >> > > > > Reviewed-by: Andrew Jones > > > > _______________________________________________ > > linux-riscv mailing list > > linux-riscv@lists.infradead.org > > http://lists.infradead.org/mailman/listinfo/linux-riscv >