From: hpa@zytor.com
To: David Laight <David.Laight@ACULAB.COM>,
"'Brian Gerst'" <brgerst@gmail.com>,
Nick Desaulniers <ndesaulniers@google.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>,
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@googlegroups.com"
<clang-built-linux@googlegroups.com>
Subject: RE: [PATCH] x86: bitops: fix build regression
Date: Thu, 07 May 2020 00:59:03 -0700 [thread overview]
Message-ID: <7C32CF96-0519-4C32-B66B-23AD9C1F1F52@zytor.com> (raw)
In-Reply-To: <60b16c05ca9e4954a7e4fcdd3075e23d@AcuMS.aculab.com>
On May 7, 2020 12:44:44 AM PDT, David Laight <David.Laight@ACULAB.COM> wrote:
>From: Brian Gerst
>> Sent: 07 May 2020 07:18
>...
>> > --- a/arch/x86/include/asm/bitops.h
>> > +++ b/arch/x86/include/asm/bitops.h
>> > @@ -54,7 +54,7 @@ arch_set_bit(long nr, volatile unsigned long
>*addr)
>> > if (__builtin_constant_p(nr)) {
>> > asm volatile(LOCK_PREFIX "orb %1,%0"
>> > : CONST_MASK_ADDR(nr, addr)
>> > - : "iq" (CONST_MASK(nr) & 0xff)
>> > + : "iq" ((u8)(CONST_MASK(nr) & 0xff))
>>
>> I think a better fix would be to make CONST_MASK() return a u8 value
>> rather than have to cast on every use.
>
>Or assign to a local variable - then it doesn't matter how
>the value is actually calculated. So:
> u8 mask = CONST_MASK(nr);
> asm volatile(LOCK_PREFIX "orb %1,%0"
> : CONST_MASK_ADDR(nr, addr)
> : "iq" mask
>
> David
>
>-
>Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes,
>MK1 1PT, UK
>Registration No: 1397386 (Wales)
"const u8" please...
--
Sent from my Android device with K-9 Mail. Please excuse my brevity.
next prev parent reply other threads:[~2020-05-07 7:59 UTC|newest]
Thread overview: 30+ 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
2020-05-10 11:59 ` 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
2020-05-07 6:18 ` 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 [this message]
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
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