x86: Wait for curthread to be set up as an indicator that the boot stack

is no longer used.

pc_curthread is set by cpu_switch after it stopped using the old
thread (or boot) stack.  This makes the smp_after_idle_runnable()
function not dependent on the internals of the scheduler operations.

Reviewed by:	markj
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D23276

This commit is contained in:

Konstantin Belousov

2020-01-20 17:23:03 +00:00

parent 6e4cafd1be

commit 65e5f2cdd4

1 changed files with 3 additions and 4 deletions

									
										sys/x86/x86/mp_x86.c
									
		+3
		-4
	
												View File
												
				@@ -1092,13 +1092,12 @@ init_secondary_tail(void)

				static void

				smp_after_idle_runnable(void *arg __unused)

				{

					struct thread *idle_td;

					struct pcpu *pc;

					int cpu;

					for (cpu = 1; cpu < mp_ncpus; cpu++) {

						idle_td = pcpu_find(cpu)->pc_idlethread;

						while (atomic_load_int(&idle_td->td_lastcpu) == NOCPU &&

						    atomic_load_int(&idle_td->td_oncpu) == NOCPU)

						pc = pcpu_find(cpu);

						while (atomic_load_ptr(&pc->pc_curthread) == (uintptr_t)NULL)

							cpu_spinwait();

						kmem_free((vm_offset_t)bootstacks[cpu], kstack_pages *

						    PAGE_SIZE);