From: Arnd Bergmann <arnd@kernel.org>
To: linux-arch@vger.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Vineet Gupta <vgupta@synopsys.com>, Arnd Bergmann <arnd@arndb.de>,
Michael Ellerman <mpe@ellerman.id.au>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: [RFC 05/12] powerpc: use linux/unaligned/le_struct.h on LE power7
Date: Sat, 8 May 2021 00:07:50 +0200 [thread overview]
Message-ID: <20210507220813.365382-6-arnd@kernel.org> (raw)
In-Reply-To: <20210507220813.365382-1-arnd@kernel.org>
From: Arnd Bergmann <arnd@arndb.de>
Little-endian POWER7 kernels disable
CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS because that is not supported on
the hardware, but the kernel still uses direct load/store for explicti
get_unaligned()/put_unaligned().
I assume this is a mistake that leads to power7 having to trap and fix
up all these unaligned accesses at a noticeable performance cost.
The fix is completely trivial, just remove the file and use the
generic version that gets it right.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
arch/powerpc/include/asm/unaligned.h | 22 ----------------------
1 file changed, 22 deletions(-)
delete mode 100644 arch/powerpc/include/asm/unaligned.h
diff --git a/arch/powerpc/include/asm/unaligned.h b/arch/powerpc/include/asm/unaligned.h
deleted file mode 100644
index ce69c5eff95e..000000000000
--- a/arch/powerpc/include/asm/unaligned.h
+++ /dev/null
@@ -1,22 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _ASM_POWERPC_UNALIGNED_H
-#define _ASM_POWERPC_UNALIGNED_H
-
-#ifdef __KERNEL__
-
-/*
- * The PowerPC can do unaligned accesses itself based on its endian mode.
- */
-#include <linux/unaligned/access_ok.h>
-#include <linux/unaligned/generic.h>
-
-#ifdef __LITTLE_ENDIAN__
-#define get_unaligned __get_unaligned_le
-#define put_unaligned __put_unaligned_le
-#else
-#define get_unaligned __get_unaligned_be
-#define put_unaligned __put_unaligned_be
-#endif
-
-#endif /* __KERNEL__ */
-#endif /* _ASM_POWERPC_UNALIGNED_H */
--
2.29.2
next prev parent reply other threads:[~2021-05-07 22:10 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-07 22:07 [RFC 0/12] Unify asm/unaligned.h around struct helper Arnd Bergmann
2021-05-07 22:07 ` [RFC 01/12] asm-generic: use asm-generic/unaligned.h for most architectures Arnd Bergmann
2021-05-07 23:02 ` Thomas Gleixner
2021-05-10 10:16 ` Geert Uytterhoeven
2021-05-10 13:12 ` Arnd Bergmann
2021-05-07 22:07 ` [RFC 02/12] openrisc: always use unaligned-struct header Arnd Bergmann
2021-05-07 23:02 ` Stafford Horne
2021-05-08 11:42 ` David Laight
2021-05-07 22:07 ` [RFC 03/12] sh: remove unaligned access for sh4a Arnd Bergmann
2021-05-10 21:11 ` Rob Landley
2021-05-07 22:07 ` [RFC 04/12] m68k: select CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS Arnd Bergmann
2021-05-10 10:18 ` Geert Uytterhoeven
2021-05-07 22:07 ` Arnd Bergmann [this message]
2021-05-07 22:07 ` [RFC 06/12] asm-generic: unaligned: remove byteshift helpers Arnd Bergmann
2021-05-08 11:38 ` Arnd Bergmann
2021-05-07 22:07 ` [RFC 07/12] asm-generic: unaligned always use struct helpers Arnd Bergmann
2021-05-07 22:07 ` [RFC 08/12] partitions: msdos: fix one-byte get_unaligned() Arnd Bergmann
2021-05-07 22:07 ` [RFC 09/12] apparmor: use get_unaligned() only for multi-byte words Arnd Bergmann
2021-05-10 8:17 ` John Johansen
2021-05-07 22:07 ` [RFC 10/12] mwifiex: re-fix for unaligned accesses Arnd Bergmann
2021-05-07 22:07 ` [RFC 11/12] netpoll: avoid put_unaligned() on single character Arnd Bergmann
2021-05-07 22:07 ` [RFC 12/12] asm-generic: simplify asm/unaligned.h Arnd Bergmann
2021-05-07 23:54 ` Linus Torvalds
2021-05-08 9:28 ` Arnd Bergmann
2021-05-08 15:23 ` Linus Torvalds
2021-05-08 11:03 ` David Laight
2021-05-08 14:18 ` David Laight
2021-05-10 6:39 ` Geert Uytterhoeven
2021-05-07 22:07 ` [RFC 0/12] Unify asm/unaligned.h around struct helper Arnd Bergmann
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