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From: Mark Rutland <mark.rutland@arm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Alexey Brodkin <Alexey.Brodkin@synopsys.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"linux-snps-arc@lists.infradead.org"
	<linux-snps-arc@lists.infradead.org>,
	"stable@vger.kernel.org" <stable@vger.kernel.org>,
	"greg@kroah.com" <greg@kroah.com>,
	"will.deacon@arm.com" <will.deacon@arm.com>,
	"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
	"David.Laight@ACULAB.COM" <David.Laight@ACULAB.COM>,
	"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
	"geert@linux-m68k.org" <geert@linux-m68k.org>
Subject: Re: [PATCH v3] devres: Explicitly align datai[] to 64-bit
Date: Mon, 9 Jul 2018 16:48:45 +0100	[thread overview]
Message-ID: <20180709154844.5p5yk34ezw2gbt3y@lakrids.cambridge.arm.com> (raw)
In-Reply-To: <20180709154521.GS2512@hirez.programming.kicks-ass.net>

On Mon, Jul 09, 2018 at 05:45:21PM +0200, Peter Zijlstra wrote:
> On Mon, Jul 09, 2018 at 05:34:27PM +0200, Peter Zijlstra wrote:
> > On Mon, Jul 09, 2018 at 04:29:58PM +0100, Mark Rutland wrote:
> > > Shouldn't that be 8? AFAICT, __alignof__(unsigned long long) is 8 on
> > > x86_32:
> > 
> > Curious, I wonder why we put that align in atomic64_32 then.
> 
> Shiny, look at this: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54188
> 

Ouch.

[mark@lakrids:~]% cat test.c
#include <stdio.h>

#define PRINT_TYPE_INFO(t) \
        printf("%10s %5d %5d\n", #t, sizeof(t), __alignof__(t))

struct ull {
        unsigned long long v;
};

int main(int argc, char *argv[])
{
        printf("%10s %5s %5s\n", "TYPE", "SIZE", "ALIGN");
        PRINT_TYPE_INFO(int);
        PRINT_TYPE_INFO(long);
        PRINT_TYPE_INFO(long long);
        PRINT_TYPE_INFO(struct ull);

        return 0;
}
[mark@lakrids:~]% gcc -m32 test.c -o test
[mark@lakrids:~]% ./test 
      TYPE  SIZE ALIGN
       int     4     4
      long     4     4
 long long     8     8
struct ull     8     4

Mark.

  parent reply	other threads:[~2018-07-09 15:48 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-09 13:45 [PATCH v3] devres: Explicitly align datai[] to 64-bit Alexey Brodkin
2018-07-09 13:45 ` Alexey Brodkin
2018-07-09 13:54 ` Peter Zijlstra
2018-07-09 13:54   ` Peter Zijlstra
2018-07-09 14:04   ` Mark Rutland
2018-07-09 14:04     ` Mark Rutland
2018-07-09 14:10     ` Geert Uytterhoeven
2018-07-09 14:10       ` Geert Uytterhoeven
2018-07-09 14:07   ` Alexey Brodkin
2018-07-09 14:07     ` Alexey Brodkin
2018-07-09 14:07 ` Peter Zijlstra
2018-07-09 14:07   ` Peter Zijlstra
2018-07-09 14:10   ` Peter Zijlstra
2018-07-09 14:10     ` Peter Zijlstra
2018-07-09 14:33     ` Alexey Brodkin
2018-07-09 14:33       ` Alexey Brodkin
2018-07-09 14:49       ` Peter Zijlstra
2018-07-09 14:49         ` Peter Zijlstra
2018-07-09 14:53         ` Alexey Brodkin
2018-07-09 14:53           ` Alexey Brodkin
2018-10-04 16:19           ` Alexey Brodkin
2018-10-04 16:19             ` Alexey Brodkin
2018-07-09 15:02         ` David Laight
2018-07-09 15:02           ` David Laight
2018-07-09 15:14           ` Peter Zijlstra
2018-07-09 15:14             ` Peter Zijlstra
2018-07-09 15:29         ` Mark Rutland
2018-07-09 15:29           ` Mark Rutland
2018-07-09 15:34           ` Peter Zijlstra
2018-07-09 15:34             ` Peter Zijlstra
2018-07-09 15:45             ` Peter Zijlstra
2018-07-09 15:45               ` Peter Zijlstra
2018-07-09 15:48               ` Mark Rutland [this message]
2018-07-09 15:48                 ` Mark Rutland
2018-07-09 16:10                 ` David Laight
2018-07-09 16:10                   ` David Laight
2018-07-09 20:28                   ` Vineet Gupta
2018-07-09 20:28                     ` Vineet Gupta

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