Rework bootstrapping

Start application processors once the kernel is completely initialized,
right before starting the scheduler. This simplifies the procedure with
regard to inter-processor pmap updates.

3 files changed, 21 insertions, 33 deletions

diff --git a/kern/kernel.c b/kern/kernel.c
index d636d54a..ea11bf2b 100644
--- a/kern/kernel.c
+++ b/kern/kernel.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2011, 2012, 2013 Richard Braun.
+ * Copyright (c) 2011-2014 Richard Braun.
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -31,10 +31,6 @@ kernel_main(void)
 {
     assert(!cpu_intr_enabled());
 
-    /* Enable interrupts to allow inter-processor pmap updates */
-    cpu_intr_enable();
-
-    /* Initialize the kernel */
     rdxtree_setup();
     cpumap_setup();
     task_setup();
@@ -42,11 +38,13 @@ kernel_main(void)
     work_setup();
     llsync_setup();
 
-    /* Rendezvous with APs */
-    cpu_mp_sync();
+    /*
+     * Enabling application processors must be the last step before starting
+     * the scheduler.
+     */
+    cpu_mp_setup();
 
-    /* Run the scheduler */
-    thread_run();
+    thread_run_scheduler();
 
     /* Never reached */
 }
@@ -56,17 +54,7 @@ kernel_ap_main(void)
 {
     assert(!cpu_intr_enabled());
 
-    /*
-     * Enable interrupts to allow inter-processor pmap updates while the BSP
-     * is initializing the kernel.
-     */
-    cpu_intr_enable();
-
-    /* Wait for the BSP to complete kernel initialization */
-    cpu_ap_sync();
-
-    /* Run the scheduler */
-    thread_run();
+    thread_run_scheduler();
 
     /* Never reached */
 }
diff --git a/kern/thread.c b/kern/thread.c
index 1d679bb6..3606279d 100644
--- a/kern/thread.c
+++ b/kern/thread.c
@@ -1324,17 +1324,14 @@ thread_bootstrap_common(unsigned int cpu)
 
     cpumap_set(&thread_active_runqs, cpu);
 
-    booter = &thread_booters[cpu];
-
     /* Initialize only what's needed during bootstrap */
+    booter = &thread_booters[cpu];
     booter->flags = 0;
     booter->preempt = 1;
     booter->sched_class = THREAD_SCHED_CLASS_IDLE;
     cpumap_fill(&booter->cpumap);
     booter->task = kernel_task;
-
     thread_runq_init(&thread_runqs[cpu], booter);
-    tcb_set_current(&booter->tcb);
 }
 
 void __init
@@ -1380,12 +1377,13 @@ thread_bootstrap(void)
     thread_ts_highest_round = THREAD_TS_INITIAL_ROUND;
 
     thread_bootstrap_common(0);
+    tcb_set_current(&thread_booters[0].tcb);
 }
 
 void __init
 thread_ap_bootstrap(void)
 {
-    thread_bootstrap_common(cpu_id());
+    tcb_set_current(&thread_booters[cpu_id()].tcb);
 }
 
 static void
@@ -1706,7 +1704,10 @@ thread_setup_runq(struct thread_runq *runq)
 void __init
 thread_setup(void)
 {
-    int i;
+    int cpu;
+
+    for (cpu = 1; (unsigned int)cpu < cpu_count(); cpu++)
+        thread_bootstrap_common(cpu);
 
     kmem_cache_init(&thread_cache, "thread", sizeof(struct thread),
                     CPU_L1_SIZE, NULL, NULL, NULL, 0);
@@ -1715,8 +1716,8 @@ thread_setup(void)
 
     thread_setup_reaper();
 
-    cpumap_for_each(&thread_active_runqs, i)
-        thread_setup_runq(&thread_runqs[i]);
+    cpumap_for_each(&thread_active_runqs, cpu)
+        thread_setup_runq(&thread_runqs[cpu]);
 }
 
 int
@@ -1878,12 +1879,12 @@ thread_wakeup(struct thread *thread)
 }
 
 void __init
-thread_run(void)
+thread_run_scheduler(void)
 {
     struct thread_runq *runq;
     struct thread *thread;
 
-    assert(cpu_intr_enabled());
+    assert(!cpu_intr_enabled());
 
     runq = thread_runq_local();
     llsync_register_cpu(thread_runq_id(runq));
@@ -1891,7 +1892,6 @@ thread_run(void)
     assert(thread == runq->current);
     assert(thread->preempt == 1);
 
-    cpu_intr_disable();
     spinlock_lock(&runq->lock);
     thread = thread_runq_get_next(thread_runq_local());
 
diff --git a/kern/thread.h b/kern/thread.h
index ea6c82e4..0efb8268 100644
--- a/kern/thread.h
+++ b/kern/thread.h
@@ -239,9 +239,9 @@ void thread_wakeup(struct thread *thread);
 /*
  * Start running threads on the local processor.
  *
- * Interrupts must be enabled when calling this function.
+ * Interrupts must be disabled when calling this function.
  */
-void __noreturn thread_run(void);
+void __noreturn thread_run_scheduler(void);
 
 /*
  * Make the calling thread release the processor.