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From: "H. Peter Anvin" <hpa@zytor.com>
To: Peter Zijlstra <peterz@infradead.org>, Michael Davidson <md@google.com>
Cc: Michal Marek <mmarek@suse.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	"David S. Miller" <davem@davemloft.net>,
	Shaohua Li <shli@kernel.org>,
	Alexander Potapenko <glider@google.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	Matthias Kaehlcke <mka@chromium.org>,
	x86@kernel.org, linux-kbuild@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org,
	linux-raid@vger.kernel.org
Subject: Re: [PATCH 5/7] x86, boot, LLVM: Use regparm=0 for memcpy and memset
Date: Thu, 22 Jun 2017 15:38:19 -0700	[thread overview]
Message-ID: <c6f5b08c-1de8-15a7-81c2-b41aad7d1c8b@zytor.com> (raw)
In-Reply-To: <20170317120855.zwqame63yvy5afhg@hirez.programming.kicks-ass.net>

On 03/17/17 05:08, Peter Zijlstra wrote:
> On Thu, Mar 16, 2017 at 05:15:18PM -0700, Michael Davidson wrote:
>> Use the standard regparm=0 calling convention for memcpy and
>> memset when building with clang.
>>
>> This is a work around for a long standing clang bug
>> (see https://llvm.org/bugs/show_bug.cgi?id=3997) where
>> clang always uses the standard regparm=0 calling convention
>> for any implcit calls to memcpy and memset that it generates
>> (eg for structure assignments and initialization) even if an
>> alternate calling convention such as regparm=3 has been specified.
> 
> Seriously, fix LLVM already.
> 

Yes, this is a real stinker, in no small part because once clang is
fixed to DTRT then this is actually broken...

	-hpa


  reply	other threads:[~2017-06-22 22:38 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-17  0:15 [PATCH 0/7] LLVM: make x86_64 kernel build with clang Michael Davidson
2017-03-17  0:15 ` [PATCH 1/7] Makefile, LLVM: add -no-integrated-as to KBUILD_[AC]FLAGS Michael Davidson
2017-04-03 22:49   ` Matthias Kaehlcke
2017-04-21  7:49   ` Masahiro Yamada
2017-04-21  7:49     ` Masahiro Yamada
2017-03-17  0:15 ` [PATCH 2/7] Makefile, x86, LLVM: disable unsupported optimization flags Michael Davidson
2017-03-17 21:32   ` H. Peter Anvin
2017-03-17 21:34     ` H. Peter Anvin
2017-04-05 18:08   ` Masahiro Yamada
2017-04-05 19:01     ` Matthias Kaehlcke
2017-04-05 19:11       ` Michael Davidson
2017-04-10 14:54         ` Masahiro Yamada
2017-03-17  0:15 ` [PATCH 3/7] x86, LLVM: suppress clang warnings about unaligned accesses Michael Davidson
2017-03-17 23:50   ` hpa
2017-04-03 23:01     ` Matthias Kaehlcke
2017-04-13 23:14       ` Matthias Kaehlcke
2017-04-13 23:55         ` H. Peter Anvin
2017-04-14  0:23           ` Matthias Kaehlcke
2017-04-14  5:30             ` hpa
2017-03-17  0:15 ` [PATCH 4/7] x86, boot, LLVM: #undef memcpy etc in string.c Michael Davidson
2017-06-22 22:31   ` Matthias Kaehlcke
2017-06-22 22:37     ` H. Peter Anvin
2017-06-30 18:32       ` Matthias Kaehlcke
2017-03-17  0:15 ` [PATCH 5/7] x86, boot, LLVM: Use regparm=0 for memcpy and memset Michael Davidson
2017-03-17 12:08   ` Peter Zijlstra
2017-06-22 22:38     ` H. Peter Anvin [this message]
2017-03-17  0:15 ` [PATCH 6/7] md/raid10, LLVM: get rid of variable length array Michael Davidson
2017-03-17 12:08   ` Peter Zijlstra
2017-03-17 12:31     ` Alexander Potapenko
2017-03-17 12:32       ` Alexander Potapenko
2017-03-17 18:03         ` Borislav Petkov
2017-03-17 18:47           ` Dmitry Vyukov
2017-03-17 18:57             ` Borislav Petkov
2017-03-17 19:05               ` Dmitry Vyukov
2017-03-17 19:26                 ` Peter Zijlstra
2017-03-17 19:26                   ` Peter Zijlstra
2017-03-17 19:29                   ` Peter Zijlstra
2017-03-24 13:50                     ` Dmitry Vyukov
2017-03-24 14:10                       ` Peter Zijlstra
2017-03-24 14:22                         ` Dmitry Vyukov
2017-03-18  0:41                 ` Fengguang Wu
2017-03-17 12:44       ` Peter Zijlstra
2017-03-17 18:52         ` Michael Davidson
2017-03-17 19:27           ` Peter Zijlstra
2017-03-17 20:04             ` hpa
2017-03-24 13:47               ` Dmitry Vyukov
2017-03-24 14:09                 ` Peter Zijlstra
2017-03-17  0:15 ` [PATCH 7/7] crypto, x86, LLVM: aesni - fix token pasting Michael Davidson
2017-04-03 23:14   ` Matthias Kaehlcke
2017-03-17  8:17 ` [PATCH 0/7] LLVM: make x86_64 kernel build with clang Dmitry Vyukov

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