[init][smp] have secondary init run in arch code up to threading, and complete in secondary thread

-move the per-cpu initialization of the gic and cortex-a9 timer into an init hook.
  This removes the hard coded call in arm/arch.c
-make sure the timer initialization happens in the pre-threading callback, in case
  a secondary init hook needs the timer.

dev/timer/arm_cortex_a9/arm_cortex_a9_timer.c

@@ -34,6 +34,7 @@
 #include <platform.h>
 #include <platform/interrupts.h>
 #include <platform/timer.h>
+#include <lk/init.h>
 
 /* driver for cortex-a9's private timer */
 #define LOCAL_TRACE 0
@@ -79,6 +80,8 @@ static struct fp_32_64 timer_freq_msec_conversion;
 static struct fp_32_64 timer_freq_usec_conversion_inverse;
 static struct fp_32_64 timer_freq_msec_conversion_inverse;
 
+static void arm_cortex_a9_timer_init_percpu(uint level);
+
 uint64_t get_global_val(void)
 {
     uint32_t lo, hi;
@@ -189,7 +192,7 @@ void arm_cortex_a9_timer_init(addr_t _scu_control_base, uint32_t freq)
 {
     scu_control_base = _scu_control_base;
 
-    arm_cortex_a9_timer_init_percpu();
+    arm_cortex_a9_timer_init_percpu(0);
 
     /* save the timer frequency for later calculations */
     timer_freq = freq;
@@ -200,7 +203,7 @@ void arm_cortex_a9_timer_init(addr_t _scu_control_base, uint32_t freq)
     fp_32_64_div_32_32(&timer_freq_msec_conversion_inverse, 1000, timer_freq);
 }
 
-void arm_cortex_a9_timer_init_percpu(void)
+static void arm_cortex_a9_timer_init_percpu(uint level)
 {
     /* disable timer */
     TIMREG(TIMER_CONTROL) = 0;
@@ -216,4 +219,9 @@ void arm_cortex_a9_timer_init_percpu(void)
     unmask_interrupt(CPU_PRIV_TIMER_INT);
 }
 
+/* secondary cpu initialize the timer just before the kernel starts with interrupts enabled */
+LK_INIT_HOOK_FLAGS(arm_cortex_a9_timer_init_percpu,
+       arm_cortex_a9_timer_init_percpu,
+       LK_INIT_LEVEL_THREADING - 1, LK_INIT_FLAG_SECONDARY_CPUS);
+
 /* vim: set ts=4 sw=4 expandtab: */

dev/timer/arm_cortex_a9/include/dev/timer/arm_cortex_a9.h

@@ -25,4 +25,3 @@
 #include <sys/types.h>
 
 void arm_cortex_a9_timer_init(addr_t scu_control_base, uint32_t freq);
-void arm_cortex_a9_timer_init_percpu(void);

dev/timer/arm_generic/arm_generic_timer.c

@@ -362,9 +362,10 @@ static void arm_generic_timer_init_secondary_cpu(uint level)
 	unmask_interrupt(timer_irq);
 }
 
+/* secondary cpu initialize the timer just before the kernel starts with interrupts enabled */
 LK_INIT_HOOK_FLAGS(arm_generic_timer_init_secondary_cpu,
 		   arm_generic_timer_init_secondary_cpu,
-		   LK_INIT_LEVEL_PLATFORM, LK_INIT_FLAG_SECONDARY_CPUS);
+		   LK_INIT_LEVEL_THREADING - 1, LK_INIT_FLAG_SECONDARY_CPUS);
 
 static void arm_generic_timer_resume_cpu(uint level)
 {