From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=pass header.oldest-pass=0 smtp.remote-ip=85.215.255.23 ARC-Seal: i=2; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=pass; t=1793348982; b=mXfFCTZ9rV42fKlhedutGhMIQ/W9SPAVt2jb3kfCB0egt/RvNGHUVdDbZ2hIaeJwkn/t rsgyC1oep4vNMqZCXcqfLrGXqrdcGVzrdducY18dYigDWyJRUFtT9g6w8uluy3vQisw0V /BNJqi/P2Aygy9J88r4akeGW8VzMo3c5Z3GCfkC5P0AaCVJ7BYGt928IrQT99T5B/6uy4 hiS3iNIXf5XOsxvtviitasv8lciiIU+vSSKAEQDUbx4ta12pFNyS+1R7T3T6c6hk7gcqA 7rJCASGV4i3BWO0RlKrveMOpTWIOlOKipTl0R2oaqDaZLls57x5sjZwKTHe0z89pUjQ== ARC-Message-Signature: i=2; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793348982; h=DMARC-Filter:X-RZG-CLASS-ID:DKIM-Signature:DKIM-Signature:X-RZG-AUTH: Received:From:To:Cc:Subject:Date:Message-ID:X-Mailer:MIME-Version: Content-Transfer-Encoding:Content-Type; bh=+UfxfAj5AhCtq4HcXmGAqALsIonnT5XRHjEbBTgxzUU=; b=dxaxe/KykvKv7Twcnfm86MRti6WYG9UWrFc/zCD63hJJsgLQFxwZXNuF/aepCFy4OXb/ TzNq7qz7t6fBSZr1mfl4AS1AvUQFXsrH4BI2oaURILaOztgJ9eQPMy/pEM7+qWI2THBPS /hRBo/1mA9H9YWTFhRd8meD4fgrUGMtBAopbwxgFufiws+VYXMgXFutUZOo9//oFvZ+1P 2bmGUR47ZO7lufImIM0ufWPWx/RT+QFV+YP/oEjA6xvEn10rOrzVWLMZ01PG0bNaJG6OG OgIQ2GkNaw1XN2PRXKE6sCXA2LPd4PIT0GW5hVqfhLC8gWSYippeW9v+dtU9yG1uRhg== ARC-Authentication-Results: i=2; smtp.subspace.kernel.org; dmarc=pass header.from=outer-limits.org; spf=pass smtp.mailfrom=outer-limits.org; dkim=pass header.d=outer-limits.org header.i=@outer-limits.org header.a=rsa-sha256 header.s=strato-dkim-0002 header.b="snhkS/ic"; dkim=pass header.d=outer-limits.org header.i=@outer-limits.org header.a=ed25519-sha256 header.s=strato-dkim-0003 header.b=4dIw4kaO; arc=pass header.oldest-pass=0 smtp.remote-ip=85.215.255.23 Received: from mo4-p00-ob.smtp.rzone.de (mo4-p00-ob.smtp.rzone.de [85.215.255.23]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4CCED606A31C for ; Fri, 30 Oct 2026 08:29:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 4CCED606A31C Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=outer-limits.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=outer-limits.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=outer-limits.org header.i=@outer-limits.org header.a=rsa-sha256 header.s=strato-dkim-0002 header.b=snhkS/ic; dkim=pass header.d=outer-limits.org header.i=@outer-limits.org header.a=ed25519-sha256 header.s=strato-dkim-0003 header.b=4dIw4kaO ARC-Seal: i=1; a=rsa-sha256; t=1793348978; cv=none; d=strato.com; s=strato-dkim-0002; b=rYx4kIkoFq76G5Y7UPv8ncfw0x6N0vseRIn3fDGX3I7hcDbeJbu5mx+jITfEdBJ0BY yfgfn6JgqP3UElK2LuBUov8/nX9MhPZ6gmPJP0/u+BCsX9Dcbr3QUxAwuhETua6IEbJW WVCWMWXBbf5JPNq2FxEtHHq1NzULfOBJZD4tHYN7bjzx5eAdDHiqwEm1Vckw8CAfTrPi rWgxozOgIQCm+xznUf3G8nkdKvI64U9q2oK5rPOUprmp3PdRRIdTzOfLfJ5sWz/r1gjw Y4SDD0RrZeYWZe5psETCieWUmoLnJ+HyplDNIsppNXEP/zgD4dUV1MV3UUUr6g8hRuiB tmCg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; t=1793348978; s=strato-dkim-0002; d=strato.com; h=Message-ID:Date:Subject:Cc:To:From:Cc:Date:From:Subject:Sender; bh=+UfxfAj5AhCtq4HcXmGAqALsIonnT5XRHjEbBTgxzUU=; b=fwFdBT/49AoSDBIatiyr5WKrbA9VoSbwG/qTcilmbueX/NAXNTMB5gpVo53/FxKXB2 4Wevw/QzgiMna6dvhnRusJs4wZ31Vjuc+it/C4CYki++57YYfngtyQWUtDokudd8Wv37 hM0E0B0cbEzHYzIHs2MquQwIfrU/VF1luVicnSrPJTrZfLpUhdIX3FqkuKYOorbFBzN5 YkitmeJje0wgrsdBhiZfoktZvnCctcW90Sd2bZcQy+243pRTu6Ify1OfrxSSI5kmt5as 9bQXmVb7Rhs8ZSIwxN+HuQ+3FwZlFovzb+HWWfr2C6KVukgtBkHD2VftSjZvWesiK90B khDQ== ARC-Authentication-Results: i=1; strato.com; arc=none; dkim=none X-RZG-CLASS-ID: mo00 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1793348978; s=strato-dkim-0002; d=outer-limits.org; h=Message-ID:Date:Subject:Cc:To:From:Cc:Date:From:Subject:Sender; bh=+UfxfAj5AhCtq4HcXmGAqALsIonnT5XRHjEbBTgxzUU=; b=snhkS/icHI6iE4y++VpYmUuzfD20bb8PR47FXYzEbE19SU+RQ2h6zpY0DVkpUrvVYP cOazogWSGAFqOThiNYlugCjIOuWdfRWlWZNywoJ+13toAwtdVknk7pnHtBUPcQXohZ5V eAMWGZ2CcFNVcHcMUpQsWHKNxt2GYXSxzgVAGTKFANngNUnsjJHM2E8ZFNdJH0zcLn44 pVmWYZY3dLRdScz0CXnaQzT/U6jMuEO5Zdzqjrog5bvpYaW4uT9fqXhabloADEnFQ8cj fK43Y89mBqKnVthYhAUop/dXUbX/rpVuVFikGhh8BRtpvGctDchrBIuVAiZ4yf73Tdra ogYQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; t=1793348978; s=strato-dkim-0003; d=outer-limits.org; h=Message-ID:Date:Subject:Cc:To:From:Cc:Date:From:Subject:Sender; bh=+UfxfAj5AhCtq4HcXmGAqALsIonnT5XRHjEbBTgxzUU=; b=4dIw4kaOx+qCcDHlUUPhJHLnZ9RmWtMKksk2TnilTUx0KmRBOuu0UdfrosBowZXTtJ VIC1xN5V7mx1KRoCHeBw== X-RZG-AUTH: ":JnkIfEGmW/AMJS6HttH4FbRVwc4dHlPLCp4e/IoHo8zEMMHAgwTfqBFXdk1Z5IDmIqDY7xpnOs6mGD64frXxHtrE3e66udIGwZnWwLgga9o=" Received: from julian.home by smtp.strato.de (RZmta 55.6.3 AUTH) with ESMTPSA id J82cde29U8Tc7Ek (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Fri, 30 Oct 2026 09:29:38 +0100 (CET) From: Julian Vetter To: Russell King Cc: Linus Walleij , Arnd Bergmann , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Julian Vetter Subject: [PATCH] ARM: fix big-endian check for IO memcpy and memset Date: Fri, 30 Oct 2026 09:29:32 +0100 Message-ID: <20261030082932.193164-1-julian@outer-limits.org> X-Mailer: git-send-email 2.53.0 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="us-ascii" The commit 7ddfe625cbc1 ("ARM: optimize memset_io()/memcpy_fromio()/memcpy_toio()") switched little-endian builds to mmioset()/mmiocpy() and intended to keep the byte-wise _memset_io()/_memcpy_fromio()/_memcpy_toio() for big-endian builds. However, the check uses __ARMBE__, which is not defined by GCC. The define used throughout the kernel is __ARMEB__ for big-endian ARM. So, big-endian builds have been using mmioset() and mmiocpy() ever since. This is a problem on ARMv5 BE32 platforms like IXP4xx, where word accesses to IO memory can end up on different byte lanes than byte accesses. Fix the typo, so big-endian builds use the correct byte-wise implementations again, as originally intended. Switching big-endian builds to the generic implementation from lib/iomem_copy.c instead is not an option either, because it also uses word accesses for the aligned parts of a buffer and thus has the same byte lane problem on BE32. ARMv6/v7 BE8 mode would work with both, but it is marked as broken and is expected to be removed, so it is not worth treating it differently from BE32. Signed-off-by: Julian Vetter --- This replaces my earlier patch that removed the byte-wise helpers: https://lore.kernel.org/all/20241203083838.3260036-1-jvetter@outer-limits.org/ I have done a compilation test with ixp4xx_defconfig and see that drivers/pci/pci-sysfs.o and drivers/mtd/maps/map_funcs.o now call _memcpy_fromio()/_memcpy_toio() instead of mmiocpy(). This is however untested on hardware. I think the problem didn't show up on Linus' hw test, because platform doesn't use those drivers. --- arch/arm/include/asm/io.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h index e6bd9e79737c..50e142f817f5 100644 --- a/arch/arm/include/asm/io.h +++ b/arch/arm/include/asm/io.h @@ -308,7 +308,7 @@ extern void _memset_io(volatile void __iomem *, int, size_t); #define writesw(p,d,l) __raw_writesw(p,d,l) #define writesl(p,d,l) __raw_writesl(p,d,l) -#ifndef __ARMBE__ +#ifndef __ARMEB__ static inline void memset_io(volatile void __iomem *dst, unsigned c, size_t count) { -- 2.53.0