On 31/10/12 17:59, Steven Rostedt wrote:
> On Wed, 2012-10-31 at 16:13 +0000, James Hogan wrote:
>> Some 32 bit architectures have 64 bit struct alignment (for example
>> metag 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.
>
> Can you test if trace-cmd still reads this correctly.
>
> git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/trace-cmd.git
>
> Run a simple:
>
> trace-cmd record -e all sleep 2
> trace-cmd report
>
> and make sure that the events report correctly your arch (metag). I just
> want to make sure that it still reads the binary data correctly. I
> should as the /sys/kernel/debug/tracing/events/header_page should
> express the difference in the offset of data.
Hi Steven,
Will do, thanks for the suggestion.
>
> Also, I wish you Cc'd LKML, as there's some changes I would have liked
> to look at, but I'm not subscribed to the linux-arch mailing list.
Sorry. I'll cc LKML for V2.
Thanks
James
>
> -- Steve
>
>>
>> Signed-off-by: James Hogan <james.hogan@xxxxxxxxxx>
>> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
>> Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
>> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
>> ---
>> 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 49491fa..15a63d8 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 */
>> };
>>
>> /*
>
>
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