From: Nick Desaulniers <ndesaulniers@google.com>
To: Brian Gerst <brgerst@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Sedat Dilek <sedat.dilek@gmail.com>,
stable <stable@vger.kernel.org>,
Jesse Brandeburg <jesse.brandeburg@intel.com>,
"kernelci . org bot" <bot@kernelci.org>,
Andy Shevchenko <andriy.shevchenko@intel.com>,
Ilie Halip <ilie.halip@gmail.com>,
"the arch/x86 maintainers" <x86@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>, Marco Elver <elver@google.com>,
"Paul E. McKenney" <paulmck@kernel.org>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Daniel Axtens <dja@axtens.net>,
Masahiro Yamada <yamada.masahiro@socionext.com>,
Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
clang-built-linux <clang-built-linux@googlegroups.com>
Subject: Re: [PATCH] x86: bitops: fix build regression
Date: Thu, 7 May 2020 12:22:30 -0700 [thread overview]
Message-ID: <CAKwvOdkBaxyOiO8+_cdBenkOj5cqcn9OhThOLmbt1uMyTW1P6g@mail.gmail.com> (raw)
In-Reply-To: <CAMzpN2idWF2_4wtPebM2B2HVyksknr9hAqK8HJi_vjQ06bgu2g@mail.gmail.com>
On Wed, May 6, 2020 at 11:18 PM Brian Gerst <brgerst@gmail.com> wrote:
>
> I think a better fix would be to make CONST_MASK() return a u8 value
> rather than have to cast on every use.
>
> Also I question the need for the "q" constraint. It was added in
> commit 437a0a54 as a workaround for GCC 3.4.4. Now that the minimum
> GCC version is 4.6, is this still necessary?
TL;DR yes
ah, thanks for the git archeology, it's useful. I don't think this is
a compiler bug however, just the compiler being more strict that the
`b` suffix on `orb` requires a 8b register operand. For 32b x86, `q`
asm constraint is required, because not all GPR's had lower 8b
register aliases, as Arnd found and HPA noted as well.
I like your suggested change to CONST_MASK, and will send that in a bit.
--
Thanks,
~Nick Desaulniers
prev parent reply other threads:[~2020-05-07 19:22 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-05 17:44 [PATCH] x86: bitops: fix build regression Nick Desaulniers
2020-05-05 18:07 ` hpa
2020-05-05 18:22 ` Nick Desaulniers
2020-05-07 11:34 ` Peter Zijlstra
2020-05-07 14:00 ` Brian Gerst
2020-05-07 19:19 ` Nick Desaulniers
2020-05-07 22:29 ` Nick Desaulniers
2020-05-08 1:57 ` Brian Gerst
2020-05-08 17:21 ` Nick Desaulniers
2020-05-08 17:31 ` H. Peter Anvin
2020-05-08 18:05 ` [PATCH v3] " Nick Desaulniers
2020-05-08 18:08 ` Nick Desaulniers
2020-05-08 18:22 ` Brian Gerst
2020-05-08 18:28 ` [PATCH v4] " Nick Desaulniers
2020-05-08 18:32 ` [PATCH v5] " Nick Desaulniers
2020-05-08 20:28 ` Nathan Chancellor
2020-05-08 23:47 ` Jesse Brandeburg
2020-05-09 4:44 ` Sedat Dilek
2020-05-09 12:20 ` Andy Shevchenko
2020-05-09 15:43 ` Brian Gerst
2020-05-11 17:22 ` Nick Desaulniers
2020-05-10 13:54 ` David Laight
2020-05-11 18:52 ` Brian Gerst
2020-05-14 23:47 ` Nick Desaulniers
2020-05-10 11:59 ` [PATCH] " David Laight
2020-05-10 12:33 ` hpa
2020-05-07 19:29 ` hpa
2020-05-06 4:30 ` Nathan Chancellor
2020-05-06 9:22 ` Sedat Dilek
2020-05-06 15:41 ` Nathan Chancellor
2020-05-06 16:37 ` Nick Desaulniers
2020-05-06 16:55 ` Ilie Halip
2020-05-06 17:05 ` [PATCH v2] " Nick Desaulniers
2020-05-07 6:18 ` [PATCH] " Brian Gerst
2020-05-07 7:02 ` hpa
2020-05-07 13:32 ` Brian Gerst
2020-05-07 15:09 ` David Laight
2020-05-07 19:31 ` hpa
2020-05-07 19:29 ` hpa
2020-05-07 7:44 ` David Laight
2020-05-07 7:59 ` hpa
2020-05-07 8:35 ` David Laight
2020-05-07 8:38 ` hpa
2020-05-07 9:17 ` Andy Shevchenko
2020-05-07 19:22 ` Nick Desaulniers [this message]
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