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?
WARNING: multiple messages have this Message-ID (diff)
From: Nathan Lynch <Nathan_Lynch@mentor.com>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: "H. Nikolaus Schaller" <hns@goldelico.com>,
Szabolcs Nagy <szabolcs.nagy@arm.com>,
Russell King <rmk+kernel@arm.linux.org.uk>,
Will Deacon <will.deacon@arm.com>,
Marek Belisko <marek@goldelico.com>,
LKML <linux-kernel@vger.kernel.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: Re: [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?
next prev parent reply other threads:[~2015-09-30 17:37 UTC|newest]
Thread overview: 38+ 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 15:56 ` H. Nikolaus Schaller
2015-09-30 16:02 ` Ard Biesheuvel
2015-09-30 16:02 ` Ard Biesheuvel
2015-09-30 16:13 ` H. Nikolaus Schaller
2015-09-30 16:13 ` H. Nikolaus Schaller
2015-09-30 16:17 ` Ard Biesheuvel
2015-09-30 16:17 ` Ard Biesheuvel
2015-09-30 17:25 ` H. Nikolaus Schaller
2015-09-30 17:25 ` H. Nikolaus Schaller
2015-09-30 17:37 ` Nathan Lynch [this message]
2015-09-30 17:37 ` Nathan Lynch
2015-09-30 17:47 ` H. Nikolaus Schaller
2015-09-30 17:47 ` H. Nikolaus Schaller
2015-09-30 18:17 ` Nathan Lynch
2015-09-30 18:17 ` Nathan Lynch
2015-09-30 19:08 ` H. Nikolaus Schaller
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
2015-10-03 20:46 ` H. Nikolaus Schaller
2015-10-14 12:47 ` H. Nikolaus Schaller
2015-10-14 12:47 ` H. Nikolaus Schaller
2015-10-14 14:16 ` Nathan Lynch
2015-10-14 14:16 ` Nathan Lynch
2015-10-15 5:52 ` H. Nikolaus Schaller
2015-10-15 5:52 ` H. Nikolaus Schaller
2015-10-15 16:37 ` Russell King - ARM Linux
2015-10-15 16:37 ` Russell King - ARM Linux
2015-10-15 16:52 ` H. Nikolaus Schaller
2015-10-15 16:52 ` H. Nikolaus Schaller
2015-10-15 17:07 ` Nathan Lynch
2015-10-15 17:07 ` Nathan Lynch
2015-10-15 17:16 ` H. Nikolaus Schaller
2015-10-15 17:16 ` H. Nikolaus Schaller
2015-10-15 17:23 ` Nathan Lynch
2015-10-15 17:23 ` Nathan Lynch
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