From: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
To: David Laight <david.laight.linux@gmail.com>,
Mingcong Bai <jeffbai@aosc.io>
Cc: linux-kernel@vger.kernel.org, Xi Ruoyao <xry111@xry111.site>,
Kexy Biscuit <kexybiscuit@aosc.io>,
stable@vger.kernel.org, kernel test robot <lkp@intel.com>,
Madhavan Srinivasan <maddy@linux.ibm.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Nicholas Piggin <npiggin@gmail.com>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] powerpc: define __LITTLE_ENDIAN and __BIG_ENDIAN for math-emu
Date: Wed, 20 May 2026 15:14:40 +0200 [thread overview]
Message-ID: <eb93d563-7042-458e-a5c0-b5389343d41b@kernel.org> (raw)
In-Reply-To: <20260517145421.2d1ac77c@pumpkin>
Le 17/05/2026 à 15:54, David Laight a écrit :
> On Sun, 17 May 2026 12:14:21 +0800
> Mingcong Bai <jeffbai@aosc.io> wrote:
>
>> Similar to commit b929926f01f2 ("sh: define __BIG_ENDIAN for math-emu"),
>> define __LITTLE_ENDIAN and __BIG_ENDIAN as 0 to mitigate build-time
>> warnings:
>>
>> ./include/math-emu/double.h:59:21: error: ‘__BIG_ENDIAN’ is not defined, evaluates to ‘0’ [-Werror=undef]
>> 59 | #if __BYTE_ORDER == __BIG_ENDIAN
>> |
>>
>> Cc: stable@vger.kernel.org
>> Fixes: 13da9e200fe4 ("Revert "endian: #define __BYTE_ORDER"")
>> Reported-by: kernel test robot <lkp@intel.com>
>> Closes: https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Foe-kbuild-all%2F202507301656.7FEX6J5W-lkp%40intel.com%2F&data=05%7C02%7Cchristophe.leroy%40csgroup.eu%7C08977974fb1c495e9bd508deb41bd275%7C8b87af7d86474dc78df45f69a2011bb5%7C0%7C0%7C639146228768693730%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=4qGulR%2BL7i7inksEbEH9jNGZS8HG80uvm3I9IyYzZww%3D&reserved=0
>> Signed-off-by: Mingcong Bai <jeffbai@aosc.io>
>> ---
>> arch/powerpc/include/asm/sfp-machine.h | 4 +++-
>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/powerpc/include/asm/sfp-machine.h b/arch/powerpc/include/asm/sfp-machine.h
>> index 8b957aabb826d..db8525605c026 100644
>> --- a/arch/powerpc/include/asm/sfp-machine.h
>> +++ b/arch/powerpc/include/asm/sfp-machine.h
>> @@ -319,10 +319,12 @@
>> #define abort() \
>> return 0
>>
>> -#ifdef __BIG_ENDIAN
>> +#ifdef __BIG_ENDIAN__
>> #define __BYTE_ORDER __BIG_ENDIAN
>> +#define __LITTLE_ENDIAN 0
>> #else
>> #define __BYTE_ORDER __LITTLE_ENDIAN
>> +#define __BIG_ENDIAN 0
>> #endif
>
> I thought the expected/correct value for __BYTE_ORDER__ was either 1234 or 4321.
> (apart from pdp11's 2143).
That's the case, in include/linux/kconfig.h we have:
#ifdef CONFIG_CPU_BIG_ENDIAN
#define __BIG_ENDIAN 4321
#else
#define __LITTLE_ENDIAN 1234
#endif
But as far as I understand the problem is that math-emu expects
__BIG_ENDIAN to be defined at all time as it has tests like:
#if __BYTE_ORDER == __BIG_ENDIAN
Christophe
next prev parent reply other threads:[~2026-05-20 13:14 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-17 4:14 [PATCH] powerpc: define __LITTLE_ENDIAN and __BIG_ENDIAN for math-emu Mingcong Bai
2026-05-17 13:54 ` David Laight
2026-05-17 15:40 ` Xi Ruoyao
2026-05-20 13:14 ` Christophe Leroy (CS GROUP) [this message]
2026-05-20 18:43 ` David Laight
2026-05-20 22:05 ` Christophe Leroy (CS GROUP)
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