From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi1-f182.google.com (mail-oi1-f182.google.com [209.85.167.182]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 60BAC33CD for ; Fri, 15 Jul 2022 14:19:14 +0000 (UTC) Received: by mail-oi1-f182.google.com with SMTP id o133so6186644oig.13 for ; Fri, 15 Jul 2022 07:19:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=VM8umUUF8nWEq+3AaJAtV0L0dG1DVjrEYAJskHQ0LoQ=; b=oPyPC8JND1jmk0qt6wIXCgqcuLOOl8rGUp32GLJy5a41WTs+t/zQKDnMPfvvn9vQYG hVNBmIiqK0CZJ7KeXvsfaLz5vgoIdjp4xEo6HcryvOJ98g7OVrHRBi+33W44+bXjbIH5 YTxxqMTh3CAaGcgmPDUM6IDfsaSWOJEpSpSzax//VcMzEfSiDPKfKy5X9/uWPGIMq9/y OeaA8Q6pvUv8mQay4ZtyK/hv8ZgKNk7gzzL0D5IazIZCptUcaMBMEKuq1L6v3n/0eq4Y jp3xHaJTKOhHzVpoh4jgNGbZoiH7M3R8hbqK5sFOwtVyzVo8kMBlwqPLUiV42dTI7CkI X85w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=VM8umUUF8nWEq+3AaJAtV0L0dG1DVjrEYAJskHQ0LoQ=; b=LPig32G0GtNhtXzoB0TjQYqvja/PIuVpb6daONCofgvR6/yEthXLKdHh2HvcRNdzI3 3Ms9Q7QH6zUOvsarJdX5AYDtSWVOV05zYbfJ9j2v2s8JdjLUhLRgRcmA1ExuxghMMtUy 9xOiMib7fABSs7OUIy3CHihWASIY9ArJfD5Qq83yNpGqqAmVgLoip5eR6Pbd+AyYSHMT BApPaMCFgz4oQs9b+1GMQQBiSl4/TnCiwhAG85/2ObmjoXSxCu0UAcGLBINhx3spSqm5 EdtHjKzV64sIynslk9iBJ2qg8PZPYpNKU1xm/ucphJgPme0eM0RwH52OKO4HO/fmVBFY 80Cw== X-Gm-Message-State: AJIora/ZtFJVlIDjcDM83+J/akqj6M+CQz2anSHpvqy2l0gSzSwTj90U hU1TuHkQyo74xWC7TkENP9U= X-Google-Smtp-Source: AGRyM1uVWqa+GN8TzJ+A70cSXNJpr/BZo6b1/5X1mjoS3V5CWTYfwZgVL70qGC+R317T+9zJh7IRug== X-Received: by 2002:a05:6808:120a:b0:333:54f1:351 with SMTP id a10-20020a056808120a00b0033354f10351mr7215208oil.70.1657894753352; Fri, 15 Jul 2022 07:19:13 -0700 (PDT) Received: from localhost ([12.97.180.36]) by smtp.gmail.com with ESMTPSA id t3-20020a056870608300b00101c9597c6fsm2302385oae.28.2022.07.15.07.19.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 15 Jul 2022 07:19:13 -0700 (PDT) Date: Fri, 15 Jul 2022 07:19:12 -0700 From: Yury Norov To: Guenter Roeck Cc: Alexander Lobakin , Arnd Bergmann , Andy Shevchenko , Mark Rutland , Matt Turner , Brian Cain , Geert Uytterhoeven , Yoshinori Sato , Rich Felker , "David S. Miller" , Kees Cook , "Peter Zijlstra (Intel)" , Marco Elver , Borislav Petkov , Tony Luck , Maciej Fijalkowski , Jesse Brandeburg , Greg Kroah-Hartman , Nathan Chancellor , Nick Desaulniers , Tom Rix , kernel test robot , linux-alpha@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-arch@vger.kernel.org, llvm@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 6/9] bitops: let optimize out non-atomic bitops on compile-time constants Message-ID: References: <20220624121313.2382500-1-alexandr.lobakin@intel.com> <20220624121313.2382500-7-alexandr.lobakin@intel.com> <20220715000402.GA512558@roeck-us.net> <20220715132633.61480-1-alexandr.lobakin@intel.com> <8c949bd4-d25a-d5f5-49be-59d52e4b6c9d@roeck-us.net> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8c949bd4-d25a-d5f5-49be-59d52e4b6c9d@roeck-us.net> On Fri, Jul 15, 2022 at 06:49:46AM -0700, Guenter Roeck wrote: > On 7/15/22 06:26, Alexander Lobakin wrote: > > From: Guenter Roeck > > Date: Thu, 14 Jul 2022 17:04:02 -0700 > > > > > On Fri, Jun 24, 2022 at 02:13:10PM +0200, Alexander Lobakin wrote: > > > > Currently, many architecture-specific non-atomic bitop > > > > implementations use inline asm or other hacks which are faster or > > > > [...] > > > > > > Cc: Mark Rutland > > > > Signed-off-by: Alexander Lobakin > > > > Reviewed-by: Marco Elver > > > > > > Building i386:allyesconfig ... failed > > > -------------- > > > Error log: > > > arch/x86/platform/olpc/olpc-xo1-sci.c: In function 'send_ebook_state': > > > arch/x86/platform/olpc/olpc-xo1-sci.c:83:63: error: logical not is only applied to the left hand side of comparison > > > > Looks like a trigger, not a cause... Anyway, this construct: > > > > unsigned char state; > > > > [...] > > > > if (!!test_bit(SW_TABLET_MODE, ebook_switch_idev->sw) == state) > > > > doesn't look legit enough. > > That redundant double-negation [of boolean value], together with > > comparing boolean to char, provokes compilers to think the author > > made logical mistakes here, although it works as expected. > > Could you please try (if it's not automated build which you can't > > modify) the following: > > > > Agreed, the existing code seems wrong. The change below looks correct > and fixes the problem. Feel free to add > > Reviewed-and-tested-by: Guenter Roeck > > to the real patch. > > Thanks, > Guenter > > > --- a/arch/x86/platform/olpc/olpc-xo1-sci.c > > +++ b/arch/x86/platform/olpc/olpc-xo1-sci.c > > @@ -80,7 +80,7 @@ static void send_ebook_state(void) > > return; > > } > > - if (!!test_bit(SW_TABLET_MODE, ebook_switch_idev->sw) == state) > > + if (test_bit(SW_TABLET_MODE, ebook_switch_idev->sw) == !!state) > > return; /* Nothing new to report. */ > > input_report_switch(ebook_switch_idev, SW_TABLET_MODE, state); > > --- > > > > We'd take it into the bitmap tree then. The series revealed > > a fistful of existing code issues already :) Would you like me to add your signed-off-by and apply, or you prefer to send it out as a patch? Thanks, Yury From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yury Norov Date: Fri, 15 Jul 2022 14:19:12 +0000 Subject: Re: [PATCH v5 6/9] bitops: let optimize out non-atomic bitops on compile-time constants Message-Id: List-Id: References: <20220624121313.2382500-1-alexandr.lobakin@intel.com> <20220624121313.2382500-7-alexandr.lobakin@intel.com> <20220715000402.GA512558@roeck-us.net> <20220715132633.61480-1-alexandr.lobakin@intel.com> <8c949bd4-d25a-d5f5-49be-59d52e4b6c9d@roeck-us.net> In-Reply-To: <8c949bd4-d25a-d5f5-49be-59d52e4b6c9d@roeck-us.net> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Guenter Roeck Cc: Alexander Lobakin , Arnd Bergmann , Andy Shevchenko , Mark Rutland , Matt Turner , Brian Cain , Geert Uytterhoeven , Yoshinori Sato , Rich Felker , "David S. Miller" , Kees Cook , "Peter Zijlstra (Intel)" , Marco Elver , Borislav Petkov , Tony Luck , Maciej Fijalkowski , Jesse Brandeburg , Greg Kroah-Hartman , Nathan Chancellor , Nick Desaulniers , Tom Rix , kernel test robot , linux-alpha@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-arch@vger.kernel.org, llvm@lists.linux.dev, linux-kernel@vger.kernel.org On Fri, Jul 15, 2022 at 06:49:46AM -0700, Guenter Roeck wrote: > On 7/15/22 06:26, Alexander Lobakin wrote: > > From: Guenter Roeck > > Date: Thu, 14 Jul 2022 17:04:02 -0700 > > > > > On Fri, Jun 24, 2022 at 02:13:10PM +0200, Alexander Lobakin wrote: > > > > Currently, many architecture-specific non-atomic bitop > > > > implementations use inline asm or other hacks which are faster or > > > > [...] > > > > > > Cc: Mark Rutland > > > > Signed-off-by: Alexander Lobakin > > > > Reviewed-by: Marco Elver > > > > > > Building i386:allyesconfig ... failed > > > -------------- > > > Error log: > > > arch/x86/platform/olpc/olpc-xo1-sci.c: In function 'send_ebook_state': > > > arch/x86/platform/olpc/olpc-xo1-sci.c:83:63: error: logical not is only applied to the left hand side of comparison > > > > Looks like a trigger, not a cause... Anyway, this construct: > > > > unsigned char state; > > > > [...] > > > > if (!!test_bit(SW_TABLET_MODE, ebook_switch_idev->sw) = state) > > > > doesn't look legit enough. > > That redundant double-negation [of boolean value], together with > > comparing boolean to char, provokes compilers to think the author > > made logical mistakes here, although it works as expected. > > Could you please try (if it's not automated build which you can't > > modify) the following: > > > > Agreed, the existing code seems wrong. The change below looks correct > and fixes the problem. Feel free to add > > Reviewed-and-tested-by: Guenter Roeck > > to the real patch. > > Thanks, > Guenter > > > --- a/arch/x86/platform/olpc/olpc-xo1-sci.c > > +++ b/arch/x86/platform/olpc/olpc-xo1-sci.c > > @@ -80,7 +80,7 @@ static void send_ebook_state(void) > > return; > > } > > - if (!!test_bit(SW_TABLET_MODE, ebook_switch_idev->sw) = state) > > + if (test_bit(SW_TABLET_MODE, ebook_switch_idev->sw) = !!state) > > return; /* Nothing new to report. */ > > input_report_switch(ebook_switch_idev, SW_TABLET_MODE, state); > > --- > > > > We'd take it into the bitmap tree then. The series revealed > > a fistful of existing code issues already :) Would you like me to add your signed-off-by and apply, or you prefer to send it out as a patch? Thanks, Yury From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yury Norov Subject: Re: [PATCH v5 6/9] bitops: let optimize out non-atomic bitops on compile-time constants Date: Fri, 15 Jul 2022 07:19:12 -0700 Message-ID: References: <20220624121313.2382500-1-alexandr.lobakin@intel.com> <20220624121313.2382500-7-alexandr.lobakin@intel.com> <20220715000402.GA512558@roeck-us.net> <20220715132633.61480-1-alexandr.lobakin@intel.com> <8c949bd4-d25a-d5f5-49be-59d52e4b6c9d@roeck-us.net> Mime-Version: 1.0 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=VM8umUUF8nWEq+3AaJAtV0L0dG1DVjrEYAJskHQ0LoQ=; b=oPyPC8JND1jmk0qt6wIXCgqcuLOOl8rGUp32GLJy5a41WTs+t/zQKDnMPfvvn9vQYG hVNBmIiqK0CZJ7KeXvsfaLz5vgoIdjp4xEo6HcryvOJ98g7OVrHRBi+33W44+bXjbIH5 YTxxqMTh3CAaGcgmPDUM6IDfsaSWOJEpSpSzax//VcMzEfSiDPKfKy5X9/uWPGIMq9/y OeaA8Q6pvUv8mQay4ZtyK/hv8ZgKNk7gzzL0D5IazIZCptUcaMBMEKuq1L6v3n/0eq4Y jp3xHaJTKOhHzVpoh4jgNGbZoiH7M3R8hbqK5sFOwtVyzVo8kMBlwqPLUiV42dTI7CkI X85w== Content-Disposition: inline In-Reply-To: <8c949bd4-d25a-d5f5-49be-59d52e4b6c9d@roeck-us.net> List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Guenter Roeck Cc: Alexander Lobakin , Arnd Bergmann , Andy Shevchenko , Mark Rutland , Matt Turner , Brian Cain , Geert Uytterhoeven , Yoshinori Sato , Rich Felker , "David S. Miller" , Kees Cook , "Peter Zijlstra (Intel)" , Marco Elver , Borislav Petkov , Tony Luck , Maciej Fijalkowski , Jesse Brandeburg , Greg Kroah-Hartman , Nathan Chancellor On Fri, Jul 15, 2022 at 06:49:46AM -0700, Guenter Roeck wrote: > On 7/15/22 06:26, Alexander Lobakin wrote: > > From: Guenter Roeck > > Date: Thu, 14 Jul 2022 17:04:02 -0700 > > > > > On Fri, Jun 24, 2022 at 02:13:10PM +0200, Alexander Lobakin wrote: > > > > Currently, many architecture-specific non-atomic bitop > > > > implementations use inline asm or other hacks which are faster or > > > > [...] > > > > > > Cc: Mark Rutland > > > > Signed-off-by: Alexander Lobakin > > > > Reviewed-by: Marco Elver > > > > > > Building i386:allyesconfig ... failed > > > -------------- > > > Error log: > > > arch/x86/platform/olpc/olpc-xo1-sci.c: In function 'send_ebook_state': > > > arch/x86/platform/olpc/olpc-xo1-sci.c:83:63: error: logical not is only applied to the left hand side of comparison > > > > Looks like a trigger, not a cause... Anyway, this construct: > > > > unsigned char state; > > > > [...] > > > > if (!!test_bit(SW_TABLET_MODE, ebook_switch_idev->sw) == state) > > > > doesn't look legit enough. > > That redundant double-negation [of boolean value], together with > > comparing boolean to char, provokes compilers to think the author > > made logical mistakes here, although it works as expected. > > Could you please try (if it's not automated build which you can't > > modify) the following: > > > > Agreed, the existing code seems wrong. The change below looks correct > and fixes the problem. Feel free to add > > Reviewed-and-tested-by: Guenter Roeck > > to the real patch. > > Thanks, > Guenter > > > --- a/arch/x86/platform/olpc/olpc-xo1-sci.c > > +++ b/arch/x86/platform/olpc/olpc-xo1-sci.c > > @@ -80,7 +80,7 @@ static void send_ebook_state(void) > > return; > > } > > - if (!!test_bit(SW_TABLET_MODE, ebook_switch_idev->sw) == state) > > + if (test_bit(SW_TABLET_MODE, ebook_switch_idev->sw) == !!state) > > return; /* Nothing new to report. */ > > input_report_switch(ebook_switch_idev, SW_TABLET_MODE, state); > > --- > > > > We'd take it into the bitmap tree then. The series revealed > > a fistful of existing code issues already :) Would you like me to add your signed-off-by and apply, or you prefer to send it out as a patch? Thanks, Yury