diff options
Diffstat (limited to 'sys/pc98/pc98/machdep.c')
| -rw-r--r-- | sys/pc98/pc98/machdep.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/sys/pc98/pc98/machdep.c b/sys/pc98/pc98/machdep.c index ed253cb..ddd958c 100644 --- a/sys/pc98/pc98/machdep.c +++ b/sys/pc98/pc98/machdep.c @@ -815,9 +815,14 @@ cpu_idle(void) #ifndef SMP if (cpu_idle_hlt) { disable_intr(); - if (procrunnable()) { + if (procrunnable()) { enable_intr(); } else { + /* + * we must absolutely guarentee that hlt is the + * absolute next instruction after sti or we + * introduce a timing window. + */ __asm __volatile("sti; hlt"); } } @@ -1758,9 +1763,9 @@ init386(first) * Initialize mutexes. * * icu_lock: in order to allow an interrupt to occur in a critical - * section, to set pcpu->ipending (etc...) properly, we - * must be able to get the icu lock, so it can't be under - * witness. + * section, to set pcpu->ipending (etc...) properly, we + * must be able to get the icu lock, so it can't be + * under witness. */ mtx_init(&Giant, "Giant", MTX_DEF | MTX_RECURSE); mtx_init(&sched_lock, "sched lock", MTX_SPIN | MTX_RECURSE); |
