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From: Nathan_Lynch@mentor.com (Nathan Lynch)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: fix vdsomunge depends on glibc specific byteswap.h
Date: Wed, 30 Sep 2015 12:37:20 -0500	[thread overview]
Message-ID: <560C1DD0.1000907@mentor.com> (raw)
In-Reply-To: <CAKv+Gu_6DibhUUPGrACCZE3S_k50rcO8A5ZcHh5c4UiDQUNApA@mail.gmail.com>

On 09/30/2015 11:17 AM, Ard Biesheuvel wrote:
> On 30 September 2015 at 18:13, H. Nikolaus Schaller <hns@goldelico.com> wrote:
>>
>> Am 30.09.2015 um 18:02 schrieb Ard Biesheuvel <ard.biesheuvel@linaro.org>:
>>>
>>> Have you tried this?
>>>
>>> #define bswap_16 __builtin_bswap16
>>> #define bswap_32 __builtin_bswap32
>>> #define bswap_64 __builtin_bswap64
>>>
>>> https://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html
>>
>> OS X host uses llvm and I am not sure if these builtins are
>> always available.
>>
> 
> I am pretty sure recent clang supports these as well. Could you please try it?

Well, I think GCC did not provide __builtin_bswap16 consistently until
the 4.8 release:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52624

That seems too recent to me.

vdsomunge makes only three or four potentially byteswapped accesses to
the ELF header.  It's not worth a lot of effort to try to use the most
optimal implementation available.  Why not just use a generic
implementation like is found in mips' elf2ecoff?

  parent reply	other threads:[~2015-09-30 17:37 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <cover.1443628457.git.hns@goldelico.com>
2015-09-30 15:56 ` [PATCH] ARM: fix vdsomunge depends on glibc specific byteswap.h H. Nikolaus Schaller
2015-09-30 16:02   ` Ard Biesheuvel
2015-09-30 16:13     ` H. Nikolaus Schaller
2015-09-30 16:17       ` Ard Biesheuvel
2015-09-30 17:25         ` H. Nikolaus Schaller
2015-09-30 17:37         ` Nathan Lynch [this message]
2015-09-30 17:47           ` H. Nikolaus Schaller
2015-09-30 18:17             ` Nathan Lynch
2015-09-30 19:08               ` H. Nikolaus Schaller
     [not found]                 ` <cover.1443791320.git.hns@goldelico.com>
2015-10-02 13:10                   ` [PATCH] ARM: fix vdsomunge not to depend " H. Nikolaus Schaller
2015-10-03  8:20                   ` H. Nikolaus Schaller
2015-10-03 20:46   ` [PATCH v2] " H. Nikolaus Schaller
2015-10-14 12:47     ` H. Nikolaus Schaller
2015-10-14 14:16       ` Nathan Lynch
2015-10-15  5:52         ` H. Nikolaus Schaller
2015-10-15 16:37           ` Russell King - ARM Linux
2015-10-15 16:52             ` H. Nikolaus Schaller
2015-10-15 17:07           ` Nathan Lynch
2015-10-15 17:16             ` H. Nikolaus Schaller
2015-10-15 17:23               ` Nathan Lynch

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