From: Stefan Agner <stefan@agner.ch> To: Nick Desaulniers <ndesaulniers@google.com> Cc: Robin Murphy <robin.murphy@arm.com>, Russell King <linux@armlinux.org.uk>, Nicolas Pitre <nicolas.pitre@linaro.org>, Mark Rutland <mark.rutland@arm.com>, Arnd Bergmann <arnd@arndb.de>, Ard Biesheuvel <ard.biesheuvel@linaro.org>, Will Deacon <will.deacon@arm.com>, julien.thierry@arm.com, LKML <linux-kernel@vger.kernel.org>, Thierry Reding <thierry.reding@gmail.com>, Nathan Chancellor <natechancellor@gmail.com>, Linux ARM <linux-arm-kernel@lists.infradead.org>, Kristof Beyls <Kristof.Beyls@arm.com>, Peter Smith <Peter.Smith@arm.com> Subject: Re: [PATCH 1/2] ARM: drop unnecessary WASM Date: Sun, 17 Mar 2019 16:44:44 +0100 [thread overview] Message-ID: <e78bcb6154a5bf5f791fe29b40188ba0@agner.ch> (raw) In-Reply-To: <CAKwvOdnb58nGXdweWTobGjqry7=9ZmfnMWnjTn8uHKt=Z5iabQ@mail.gmail.com> On 06.03.2019 01:47, Nick Desaulniers wrote: > On Tue, Mar 5, 2019 at 3:39 PM Robin Murphy <robin.murphy@arm.com> wrote: >> >> Hi Stefan, >> >> On 2019-03-05 10:18 pm, Stefan Agner wrote: >> > The W macro for generating wide instructions when targeting Thumb-2 >> > is not required for the preload data instructions (pld, pldw) since >> > they are only available as wide instructions. The GNU assembler seems >> > to work with or without the .w appended when compiling an Thumb-2 >> > kernel. However, Clang's integrated assembler does not consider the >> > .w variants as valid instructions: >> > >> > ./arch/arm/include/asm/processor.h:133:5: error: invalid instruction >> > "pldw.w\t%a0 \n" >> > ^ >> > <inline asm>:2:1: note: instantiated into assembly here >> > pldw.w [r0] >> > ^ >> > 1 error generated. >> >> Have you filed a bug against Clang for that? Something like "pldwal.w" > > Yes; please. For each deficiency you find, please file a bug. We're > working on identifying what's missing from Clang's integrated > assembler support. Given the list of issues, it's easier to estimate > how much effort is needed, which helps us allocate resources towards > fixing those issues better. > > It would be good to know if pldw.w is valid under UAL or not. As far as I understand the Arm ARM it is valid under UAL. Reported a bug in LLVM's bug tracker: https://bugs.llvm.org/show_bug.cgi?id=40972 Will send a v2 patch mentioning this is really a work around for LLVM and link to the bug report. > > Hopefully, the ARM kernel team can stress the importance of assembler > support for their ISA to their LLVM team. -- Stefan
WARNING: multiple messages have this Message-ID (diff)
From: Stefan Agner <stefan@agner.ch> To: Nick Desaulniers <ndesaulniers@google.com> Cc: Nicolas Pitre <nicolas.pitre@linaro.org>, Mark Rutland <mark.rutland@arm.com>, Arnd Bergmann <arnd@arndb.de>, Ard Biesheuvel <ard.biesheuvel@linaro.org>, julien.thierry@arm.com, Will Deacon <will.deacon@arm.com>, Russell King <linux@armlinux.org.uk>, LKML <linux-kernel@vger.kernel.org>, Thierry Reding <thierry.reding@gmail.com>, Peter Smith <Peter.Smith@arm.com>, Kristof Beyls <Kristof.Beyls@arm.com>, Nathan Chancellor <natechancellor@gmail.com>, Robin Murphy <robin.murphy@arm.com>, Linux ARM <linux-arm-kernel@lists.infradead.org> Subject: Re: [PATCH 1/2] ARM: drop unnecessary WASM Date: Sun, 17 Mar 2019 16:44:44 +0100 [thread overview] Message-ID: <e78bcb6154a5bf5f791fe29b40188ba0@agner.ch> (raw) In-Reply-To: <CAKwvOdnb58nGXdweWTobGjqry7=9ZmfnMWnjTn8uHKt=Z5iabQ@mail.gmail.com> On 06.03.2019 01:47, Nick Desaulniers wrote: > On Tue, Mar 5, 2019 at 3:39 PM Robin Murphy <robin.murphy@arm.com> wrote: >> >> Hi Stefan, >> >> On 2019-03-05 10:18 pm, Stefan Agner wrote: >> > The W macro for generating wide instructions when targeting Thumb-2 >> > is not required for the preload data instructions (pld, pldw) since >> > they are only available as wide instructions. The GNU assembler seems >> > to work with or without the .w appended when compiling an Thumb-2 >> > kernel. However, Clang's integrated assembler does not consider the >> > .w variants as valid instructions: >> > >> > ./arch/arm/include/asm/processor.h:133:5: error: invalid instruction >> > "pldw.w\t%a0 \n" >> > ^ >> > <inline asm>:2:1: note: instantiated into assembly here >> > pldw.w [r0] >> > ^ >> > 1 error generated. >> >> Have you filed a bug against Clang for that? Something like "pldwal.w" > > Yes; please. For each deficiency you find, please file a bug. We're > working on identifying what's missing from Clang's integrated > assembler support. Given the list of issues, it's easier to estimate > how much effort is needed, which helps us allocate resources towards > fixing those issues better. > > It would be good to know if pldw.w is valid under UAL or not. As far as I understand the Arm ARM it is valid under UAL. Reported a bug in LLVM's bug tracker: https://bugs.llvm.org/show_bug.cgi?id=40972 Will send a v2 patch mentioning this is really a work around for LLVM and link to the bug report. > > Hopefully, the ARM kernel team can stress the importance of assembler > support for their ISA to their LLVM team. -- Stefan _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2019-03-17 15:44 UTC|newest] Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-03-05 22:18 [PATCH 1/2] ARM: drop unnecessary WASM Stefan Agner 2019-03-05 22:18 ` Stefan Agner 2019-03-05 22:18 ` [PATCH 2/2] ARM: drop -mauto-it Stefan Agner 2019-03-05 22:18 ` Stefan Agner 2019-03-05 22:21 ` Nick Desaulniers 2019-03-05 22:21 ` Nick Desaulniers 2019-03-05 22:40 ` Stefan Agner 2019-03-05 22:40 ` Stefan Agner 2019-03-05 23:20 ` Nick Desaulniers 2019-03-05 23:20 ` Nick Desaulniers 2019-03-05 23:39 ` [PATCH 1/2] ARM: drop unnecessary WASM Robin Murphy 2019-03-05 23:39 ` Robin Murphy 2019-03-06 0:47 ` Nick Desaulniers 2019-03-06 0:47 ` Nick Desaulniers 2019-03-17 15:44 ` Stefan Agner [this message] 2019-03-17 15:44 ` Stefan Agner 2019-03-06 7:58 ` Stefan Agner 2019-03-06 7:58 ` Stefan Agner
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