Re: [RFC PATCH v3 5/7] powerpc: 'current_set' is now a table of task_struct pointers

Le 03/10/2018 à 07:41, Nicholas Piggin a écrit :

On Mon,  1 Oct 2018 12:30:27 +0000 (UTC)
Christophe Leroy [off-list ref] wrote:

quoted

The table of pointers 'current_set' has been used for retrieving
the stack and current. They used to be thread_info pointers as
they were pointing to the stack and current was taken from the
'task' field of the thread_info.

Now, the pointers of 'current_set' table are now both pointers
to task_struct and pointers to thread_info.

As they are used to get current, and the stack pointer is
retrieved from current's stack field, this patch changes
their type to task_struct, and renames secondary_ti to
secondary_current.

I'm not sure if current_set is actually needed is it? Because
64-bit already initializes paca->ksave / PACAKSAVE. That might
be a cleanup to do after your series.

head_64.S contains:

__secondary_start:
	/* Set thread priority to MEDIUM */
	HMT_MEDIUM

	/* Initialize the kernel stack */
	LOAD_REG_ADDR(r3, current_set)
	sldi	r28,r24,3		/* get current_set[cpu#]	 */
	ldx	r14,r3,r28
	addi	r14,r14,THREAD_SIZE-STACK_FRAME_OVERHEAD
	std	r14,PACAKSAVE(r13)


32-bit doesn't seem to use it, it only uses secondary_ti it seems.

Reviewed-by: Nicholas Piggin <npiggin@gmail.com>

Christophe