Re: [patch V2 09/37] rseq: Introduce struct rseq_event

[Thomas Gleixner <tglx@linutronix.de>]

On Mon, Aug 25 2025 at 14:11, Mathieu Desnoyers wrote:
>> + * @sched_switch:	True if the task was scheduled out
>> + * @has_rseq:		True if the task has a rseq pointer installed
>> + */
>> +struct rseq_event {
>> +	union {
>> +		u32				all;
>> +		struct {
>> +			union {
>> +				u16		events;
>> +				struct {
>> +					u8	sched_switch;
>> +				};
>
> Is alpha still supported, or can we assume bytewise loads/stores ?

Alpha is on life support, but that does not mean we have to cater for it
in new features.

> Are those events meant to each consume 1 byte (which limits us to 2
> events for a 2-byte "events"/4-byte "all"), or is the plan to update
> them with bitwise or/~ and ?

No. Bitwise or/and is creating horrible ASM code and needs serialization
in the worst case.

There is a no need for tons of events. See changes further down the
series.

Thanks,

        tglx