From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Subject: Re: [PATCH v2 04/44] trace/ring_buffer: handle 64bit aligned structs Date: Fri, 07 Dec 2012 20:24:11 -0500 Message-ID: <1354929851.17101.105.camel@gandalf.local.home> References: <1354723742-6195-1-git-send-email-james.hogan@imgtec.com> <1354723742-6195-5-git-send-email-james.hogan@imgtec.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-15" Content-Transfer-Encoding: 7bit Return-path: Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:3351 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757465Ab2LHBYO (ORCPT ); Fri, 7 Dec 2012 20:24:14 -0500 In-Reply-To: <1354723742-6195-5-git-send-email-james.hogan@imgtec.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: James Hogan Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, Arnd Bergmann , Frederic Weisbecker , Ingo Molnar On Wed, 2012-12-05 at 16:08 +0000, James Hogan wrote: > Some 32 bit architectures have 64 bit struct alignment (for example > Meta which has 64 bit read/write instructions). These require 8 byte > alignment of event data too, so use CONFIG_HAVE_64BIT_ALIGNED_STRUCT > instead of CONFIG_64BIT to decide alignment, and align > buffer_data_page::data accordingly. > > Signed-off-by: James Hogan Acked-by: Steven Rostedt -- Steve > Cc: Frederic Weisbecker > Cc: Ingo Molnar > --- > kernel/trace/ring_buffer.c | 7 +++++-- > 1 files changed, 5 insertions(+), 2 deletions(-) > > diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c > index b979426..c4dc029 100644 > --- a/kernel/trace/ring_buffer.c > +++ b/kernel/trace/ring_buffer.c > @@ -177,7 +177,8 @@ void tracing_off_permanent(void) > #define RB_MAX_SMALL_DATA (RB_ALIGNMENT * RINGBUF_TYPE_DATA_TYPE_LEN_MAX) > #define RB_EVNT_MIN_SIZE 8U /* two 32bit words */ > > -#if !defined(CONFIG_64BIT) || defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) > +#if !defined(CONFIG_HAVE_64BIT_ALIGNED_STRUCT) || \ > + defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) > # define RB_FORCE_8BYTE_ALIGNMENT 0 > # define RB_ARCH_ALIGNMENT RB_ALIGNMENT > #else > @@ -185,6 +186,8 @@ void tracing_off_permanent(void) > # define RB_ARCH_ALIGNMENT 8U > #endif > > +#define RB_ALIGN_DATA __aligned(RB_ARCH_ALIGNMENT) > + > /* define RINGBUF_TYPE_DATA for 'case RINGBUF_TYPE_DATA:' */ > #define RINGBUF_TYPE_DATA 0 ... RINGBUF_TYPE_DATA_TYPE_LEN_MAX > > @@ -333,7 +336,7 @@ EXPORT_SYMBOL_GPL(ring_buffer_event_data); > struct buffer_data_page { > u64 time_stamp; /* page time stamp */ > local_t commit; /* write committed index */ > - unsigned char data[]; /* data of buffer page */ > + unsigned char data[] RB_ALIGN_DATA; /* data of buffer page */ > }; > > /*