Re: [PATCH 4/4] rseq/selftests: Implement MIPS support

[Mathieu Desnoyers]

----- On Jun 15, 2018, at 6:58 AM, James Hogan jhogan@xxxxxxxxxx wrote:

> On Thu, Jun 14, 2018 at 04:52:10PM -0700, Paul Burton wrote:
>> +#define __RSEQ_ASM_DEFINE_TABLE(version, flags,	start_ip,			\
> 
> Nit: technically all these \'s are on 81st column...
> 
>> +#define __RSEQ_ASM_DEFINE_ABORT(table_label, label, teardown,			\
>> +				abort_label, version, flags,			\
>> +				start_ip, post_commit_offset, abort_ip)		\
>> +		".balign 32\n\t"						\
> 
> ARM doesn't do this for DEFINE_ABORT. Is it intentional that we do for
> MIPS?

Given that include/uapi/linux/rseq.h declares struct rseq_cs as
__attribute__((aligned(4 * sizeof(__u64)))), and considering this
comment:

/*
 * struct rseq_cs is aligned on 4 * 8 bytes to ensure it is always
 * contained within a single cache-line. It is usually declared as
 * link-time constant data.
 */

The .balign 32 is the right thing to do here. I will add a .balign 32
to ARM selftests code as well.

Thanks,

Mathieu

> 
> Thanks
> James

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com