From: Arnd Bergmann <arnd@kernel.org>
To: linux-arch@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>, Vineet Gupta <vgupta@synopsys.com>,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
Paul Mackerras <paulus@samba.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: [PATCH v2 05/13] powerpc: use linux/unaligned/le_struct.h on LE power7
Date: Fri, 14 May 2021 12:00:53 +0200 [thread overview]
Message-ID: <20210514100106.3404011-6-arnd@kernel.org> (raw)
In-Reply-To: <20210514100106.3404011-1-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:[~2021-05-14 10:04 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-14 10:00 [PATCH v2 00/13] Unify asm/unaligned.h around struct helper Arnd Bergmann
2021-05-14 10:00 ` Arnd Bergmann [this message]
2021-05-14 11:48 ` [PATCH v2 05/13] powerpc: use linux/unaligned/le_struct.h on LE power7 Segher Boessenkool
2021-05-14 13:02 ` Arnd Bergmann
2021-05-14 17:32 ` [PATCH v2 00/13] Unify asm/unaligned.h around struct helper Linus Torvalds
2021-05-14 18:51 ` Vineet Gupta
2021-05-14 19:22 ` Linus Torvalds
2021-05-14 19:45 ` Vineet Gupta
2021-05-14 20:19 ` Linus Torvalds
2021-05-14 19:31 ` Arnd Bergmann
2021-12-16 17:29 ` Ard Biesheuvel
2021-12-16 17:42 ` Linus Torvalds
2021-12-16 17:49 ` David Laight
2021-12-16 18:56 ` Segher Boessenkool
2021-12-17 12:34 ` David Laight
2021-12-17 13:35 ` Segher Boessenkool
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