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From: James Hogan <james.hogan@imgtec.com>
To: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>,
	James Hogan <james.hogan@imgtec.com>,
	Balbir Singh <bsingharora@gmail.com>,
	Ingo Molnar <mingo@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Eric Paris <eparis@redhat.com>, Will Drewry <wad@chromium.org>,
	James Morris <james.l.morris@oracle.com>
Subject: [PATCH v2 03/44] Add CONFIG_HAVE_64BIT_ALIGNED_STRUCT for taskstats
Date: Wed, 5 Dec 2012 16:08:21 +0000	[thread overview]
Message-ID: <1354723742-6195-4-git-send-email-james.hogan@imgtec.com> (raw)
Message-ID: <20121205160821.MVeqizFkfqJ-yTyej-mNbXOmcIzzjLlyxNoP0stb4ME@z> (raw)
In-Reply-To: <1354723742-6195-1-git-send-email-james.hogan@imgtec.com>

On 64 bit architectures with no efficient unaligned access, taskstats
has to add some padding to a reply to prevent unaligned access warnings.
However this also needs to apply to 32 bit architectures with 64 bit
struct alignment such as metag (which has 64 bit memory accesses).

This is solved by adding a new Kconfig symbol
CONFIG_HAVE_64BIT_ALIGNED_STRUCT which defaults to CONFIG_64BIT, and can
be explicitly selected by CONFIG_METAG. Taskstats then uses this symbol
instead of CONFIG_64BIT to determine whether to add the padding.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: Will Drewry <wad@chromium.org>
Cc: James Morris <james.l.morris@oracle.com>
---
 arch/Kconfig       |   16 ++++++++++++++++
 kernel/taskstats.c |    3 ++-
 2 files changed, 18 insertions(+), 1 deletions(-)

diff --git a/arch/Kconfig b/arch/Kconfig
index 366ec06..dc7ffb1 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -93,6 +93,22 @@ config UPROBES
 
 	  If in doubt, say "N".
 
+config HAVE_64BIT_ALIGNED_STRUCT
+	bool
+	default 64BIT
+	help
+	  Some architectures have 64bit struct alignment (64 bit
+	  architectures and some 32 bit architectures which can do
+	  64 bit accesses).
+
+	  This symbol should be selected by an architecture if it has
+	  a 64 bit struct alignment requirement even though it isn't
+	  a 64 bit architecture (64 bit architectures have this on by
+	  default).
+
+	  See Documentation/unaligned-memory-access.txt for more
+	  information on the topic of unaligned memory accesses.
+
 config HAVE_EFFICIENT_UNALIGNED_ACCESS
 	bool
 	help
diff --git a/kernel/taskstats.c b/kernel/taskstats.c
index 145bb4d..afaa4c2 100644
--- a/kernel/taskstats.c
+++ b/kernel/taskstats.c
@@ -364,7 +364,8 @@ static int parse(struct nlattr *na, struct cpumask *mask)
 	return ret;
 }
 
-#if defined(CONFIG_64BIT) && !defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
+#if defined(CONFIG_HAVE_64BIT_ALIGNED_STRUCT) && \
+	!defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
 #define TASKSTATS_NEEDS_PADDING 1
 #endif
 
-- 
1.7.7.6



  parent reply	other threads:[~2012-12-05 16:09 UTC|newest]

Thread overview: 125+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-12-05 16:08 [PATCH v2 00/44] Meta Linux Kernel Port James Hogan
2012-12-05 16:08 ` [PATCH v2 01/44] asm-generic/io.h: remove asm/cacheflush.h include James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` [PATCH v2 02/44] asm-generic/unistd.h: handle symbol prefixes in cond_syscall James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` James Hogan [this message]
2012-12-05 16:08   ` [PATCH v2 03/44] Add CONFIG_HAVE_64BIT_ALIGNED_STRUCT for taskstats James Hogan
2012-12-08  3:43   ` H. Peter Anvin
2012-12-10 10:22     ` James Hogan
2012-12-10 12:55       ` Geert Uytterhoeven
2012-12-10 12:55         ` Geert Uytterhoeven
2012-12-17  9:51         ` James Hogan
2012-12-17 19:11           ` David Miller
2012-12-05 16:08 ` [PATCH v2 04/44] trace/ring_buffer: handle 64bit aligned structs James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-08  1:24   ` Steven Rostedt
2012-12-10 10:27     ` James Hogan
2012-12-10 10:27       ` James Hogan
2012-12-05 16:08 ` [PATCH v2 05/44] Revert some of "binfmt_elf: cleanups" James Hogan
2012-12-05 16:08   ` James Hogan
     [not found] ` <1354723742-6195-1-git-send-email-james.hogan-1AXoQHu6uovQT0dZR+AlfA@public.gmane.org>
2012-12-05 16:08   ` [PATCH v2 06/44] of/vendor-prefixes: add Imagination Technologies James Hogan
2012-12-05 16:08     ` James Hogan
2012-12-05 22:28     ` Grant Likely
2012-12-05 22:28       ` Grant Likely
2012-12-06  9:24       ` James Hogan
2012-12-05 16:08 ` [PATCH v2 07/44] metag: Add MAINTAINERS entry James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` [PATCH v2 08/44] metag: Headers for core arch constants James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` [PATCH v2 09/44] metag: Header for core memory mapped registers James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` [PATCH v2 10/44] metag: Boot James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` [PATCH v2 11/44] metag; TBX header James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` [PATCH v2 12/44] metag: TBX source James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 18:53   ` Joe Perches
2012-12-05 18:53     ` Joe Perches
2012-12-06  9:35     ` James Hogan
2012-12-06 12:59       ` Joe Perches
2012-12-06 15:03         ` James Hogan
2012-12-05 16:08 ` [PATCH v2 13/44] metag: Cache/TLB handling James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` [PATCH v2 14/44] metag: Memory management James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` [PATCH v2 15/44] metag: Memory handling James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` [PATCH v2 16/44] metag: Huge TLB James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` [PATCH v2 17/44] metag: Highmem support James Hogan
2012-12-05 16:08 ` [PATCH v2 18/44] metag: TCM support James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` [PATCH v2 19/44] metag: Signal handling James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 17:16   ` Al Viro
2012-12-06 11:17     ` James Hogan
2012-12-06 22:09       ` [braindump][RFC] signals and syscall restarts (Re: [PATCH v2 19/44] metag: Signal handling) Al Viro
2012-12-08  7:44         ` Al Viro
2012-12-15 16:26           ` Jonas Bonn
2012-12-15 17:07             ` Al Viro
2012-12-08 18:14         ` Al Viro
2012-12-08 18:14           ` Al Viro
2012-12-12  9:44           ` James Hogan
2012-12-10 10:40         ` James Hogan
2012-12-05 16:08 ` [PATCH v2 20/44] metag: Device tree James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` [PATCH v2 21/44] metag: ptrace James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` [PATCH v2 22/44] metag: Time keeping James Hogan
2013-01-04 10:05   ` Vineet Gupta
2013-01-04 12:21     ` James Hogan
2013-01-04 12:48       ` Vineet Gupta
2013-01-04 13:11         ` James Hogan
2012-12-05 16:08 ` [PATCH v2 23/44] metag: Traps James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 17:40   ` Al Viro
2012-12-06 11:43     ` James Hogan
2012-12-05 16:08 ` [PATCH v2 24/44] metag: IRQ handling James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` [PATCH v2 25/44] metag: System Calls James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` [PATCH v2 26/44] metag: Scheduling/Process management James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` [PATCH v2 27/44] metag: Module support James Hogan
2012-12-05 16:08 ` [PATCH v2 28/44] metag: Atomics, locks and bitops James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` [PATCH v2 29/44] metag: Basic documentation James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` [PATCH v2 30/44] metag: SMP support James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` [PATCH v2 31/44] metag: DMA James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` [PATCH v2 32/44] metag: Optimised library functions James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` [PATCH v2 33/44] metag: Stack unwinding James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` [PATCH v2 34/44] metag: Various other headers James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` [PATCH v2 35/44] mm: define VM_GROWSUP for CONFIG_METAG James Hogan
2012-12-05 16:08 ` [PATCH v2 36/44] Add metag to various Kconfig dependency lists James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` [PATCH v2 37/44] metag: Build infrastructure James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` [PATCH v2 38/44] metag: Perf James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` [PATCH v2 39/44] metag: ftrace support James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` [PATCH v2 40/44] scripts/checkstack.pl: Add metag support James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:08 ` [PATCH v2 41/44] metag: OProfile James Hogan
2012-12-05 16:08   ` James Hogan
2012-12-05 16:09 ` [PATCH v2 42/44] metag: Add JTAG Debug Adapter (DA) support James Hogan
2012-12-05 16:09 ` [PATCH v2 43/44] tty/metag_da: Add metag DA TTY driver James Hogan
2012-12-05 16:09   ` James Hogan
2012-12-05 17:24   ` Alan Cox
2013-01-04 14:11     ` James Hogan
2013-01-04 17:00       ` Alan Cox
2013-01-07 11:30         ` James Hogan
2013-01-07 11:54           ` Alan Cox
2012-12-05 16:09 ` [PATCH v2 44/44] fs: imgdafs: Add IMG DAFS filesystem for metag James Hogan
2012-12-05 17:11 ` [PATCH v2 00/44] Meta Linux Kernel Port Al Viro
2012-12-05 18:39   ` Al Viro
2012-12-18 16:09     ` James Hogan
2012-12-06  9:19   ` James Hogan

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