task: Wait for HOOK_INIT completion before scheduling tasks

Until HOOK_INIT has completed, do not allow any tasks other than HOOKS
or IDLE to be scheduled. Programmers often make the assumption that
a HOOK_INIT function is guaranteed to be run before task code that depends
on it, so let's make it so.

BUG=chromium:649398
BRANCH=None
TEST=Manual on kevin, compare boot without patch:

...
[0.004 power state 0 = G3, in 0x0008] <-- from chipset task
RTC: 0x00000000 (0.00 s)
[0.004 power state 4 = G3->S5, in 0x0008]
RTC: 0x00000000 (0.00 s)
[0.005 clear MKBP fifo]
[0.006 clear MKBP fifo]
[0.006 KB init state: ... <-- from keyscan task
[0.012 SW 0x05]
[0.155 hash start 0x00020000 0x00019a38]
[0.158 HOOK_INIT DONE!]

... to boot with patch:

...
RTC: 0x58cc614c (1489789260.00 s)
[0.004 clear MKBP fifo]
[0.005 clear MKBP fifo]
[0.010 SW 0x05]
[0.155 hash start 0x00020000 0x000198e0]
[0.157 HOOK_INIT DONE!]
...

Also, verify kevin boots to OS and is generally functional through
sysjump and basic tasks, and verify elm (stm32f0 / cortex-m0) boots.

Change-Id: If56fab05ce9b9650feb93c5cfc2d084aa281e622
Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/456628
Commit-Ready: Shawn N <shawnn@chromium.org>
Tested-by: Shawn N <shawnn@chromium.org>
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>

7 files changed, 43 insertions, 24 deletions

diff --git a/common/console.c b/common/console.c
index 402befc622..bb4195d584 100644
--- a/common/console.c
+++ b/common/console.c
@@ -647,8 +647,7 @@ void console_has_input(void)
 #endif
 
 	/* Wake up the console task */
-	if (task_start_called())
-		task_wake(TASK_ID_CONSOLE);
+	task_wake(TASK_ID_CONSOLE);
 }
 
 void console_task(void)
diff --git a/core/cortex-m/task.c b/core/cortex-m/task.c
index f23b8142ff..6b978c9d33 100644
--- a/core/cortex-m/task.c
+++ b/core/cortex-m/task.c
@@ -167,6 +167,12 @@ static int need_resched_or_profiling;
  * make a call to enable all tasks.
  */
 static uint32_t tasks_ready = (1 << TASK_ID_HOOKS);
+/*
+ * Initially allow only the HOOKS and IDLE task to run, regardless of ready
+ * status, in order for HOOK_INIT to complete before other tasks.
+ * task_enable_all_tasks() will open the flood gates.
+ */
+static uint32_t tasks_enabled = (1 << TASK_ID_HOOKS) | (1 << TASK_ID_IDLE);
 
 static int start_called;  /* Has task swapping started */
 
@@ -271,8 +277,8 @@ void svc_handler(int desched, task_id_t resched)
 	ASSERT(resched <= TASK_ID_COUNT);
 	tasks_ready |= 1 << resched;
 
-	ASSERT(tasks_ready);
-	next = __task_id_to_ptr(__fls(tasks_ready));
+	ASSERT(tasks_ready & tasks_enabled);
+	next = __task_id_to_ptr(__fls(tasks_ready & tasks_enabled));
 
 #ifdef CONFIG_TASK_PROFILING
 	/* Track time in interrupts */
@@ -443,8 +449,8 @@ uint32_t task_wait_event_mask(uint32_t event_mask, int timeout_us)
 
 void task_enable_all_tasks(void)
 {
-	/* Mark all tasks as ready to run. */
-	tasks_ready = (1 << TASK_ID_COUNT) - 1;
+	/* Mark all tasks as ready and able to run. */
+	tasks_ready = tasks_enabled = (1 << TASK_ID_COUNT) - 1;
 	/* Reschedule the highest priority task. */
 	__schedule(0, 0);
 }
diff --git a/core/cortex-m0/switch.S b/core/cortex-m0/switch.S
index 95ea29e765..4b5ae23838 100644
--- a/core/cortex-m0/switch.S
+++ b/core/cortex-m0/switch.S
@@ -67,7 +67,7 @@ __task_start:
   adds r2, #17*4          @ put the pointer at the top of the stack
   movs r1, #0             @ __Schedule parameter : re-schedule nothing
   msr  psp, r2            @ setup a thread stack up to the first context switch
-  movs r2, #1
+  movs r2, #1             @ r2 = TASK_SCHEDULER_INIT
   isb                     @ ensure the write is done
   msr control, r3
   movs r3, r0
diff --git a/core/cortex-m0/task.c b/core/cortex-m0/task.c
index 8796983127..32f67e0d62 100644
--- a/core/cortex-m0/task.c
+++ b/core/cortex-m0/task.c
@@ -134,6 +134,12 @@ static task_ *current_task = (task_ *)scratchpad;
  * make a call to enable all tasks.
  */
 static uint32_t tasks_ready = (1 << TASK_ID_HOOKS);
+/*
+ * Initially allow only the HOOKS and IDLE task to run, regardless of ready
+ * status, in order for HOOK_INIT to complete before other tasks.
+ * task_enable_all_tasks() will open the flood gates.
+ */
+static uint32_t tasks_enabled = (1 << TASK_ID_HOOKS) | (1 << TASK_ID_IDLE);
 
 static int start_called;  /* Has task swapping started */
 
@@ -234,8 +240,8 @@ task_  __attribute__((noinline)) *__svc_handler(int desched, task_id_t resched)
 	}
 	tasks_ready |= 1 << resched;
 
-	ASSERT(tasks_ready);
-	next = __task_id_to_ptr(__fls(tasks_ready));
+	ASSERT(tasks_ready & tasks_enabled);
+	next = __task_id_to_ptr(__fls(tasks_ready & tasks_enabled));
 
 #ifdef CONFIG_TASK_PROFILING
 	/* Track additional time in re-sched exception context */
@@ -442,8 +448,8 @@ uint32_t task_wait_event_mask(uint32_t event_mask, int timeout_us)
 
 void task_enable_all_tasks(void)
 {
-	/* Mark all tasks as ready to run. */
-	tasks_ready = (1 << TASK_ID_COUNT) - 1;
+	/* Mark all tasks as ready and able to run. */
+	tasks_ready = tasks_enabled = (1 << TASK_ID_COUNT) - 1;
 	/* Reschedule the highest priority task. */
 	__schedule(0, 0);
 }
diff --git a/core/minute-ia/task.c b/core/minute-ia/task.c
index 0d131ae318..e3676e292c 100644
--- a/core/minute-ia/task.c
+++ b/core/minute-ia/task.c
@@ -145,6 +145,12 @@ static int need_resched_or_profiling;
  * make a call to enable all tasks.
  */
 static uint32_t tasks_ready = (1 << TASK_ID_HOOKS);
+/*
+ * Initially allow only the HOOKS and IDLE task to run, regardless of ready
+ * status, in order for HOOK_INIT to complete before other tasks.
+ * task_enable_all_tasks() will open the flood gates.
+ */
+static uint32_t tasks_enabled = (1 << TASK_ID_HOOKS) | (1 << TASK_ID_IDLE);
 
 static int start_called;  /* Has task swapping started */
 
@@ -217,10 +223,6 @@ uint32_t switch_handler(int desched, task_id_t resched)
 	}
 #endif
 
-	/* Stay in hook till task_enable_all_tasks() */
-	if (!task_start_called() && tasks_ready > 3)
-		tasks_ready = 3;
-
 	current = current_task;
 
 #ifdef CONFIG_DEBUG_STACK_OVERFLOW
@@ -242,8 +244,8 @@ uint32_t switch_handler(int desched, task_id_t resched)
 	}
 	tasks_ready |= 1 << resched;
 
-	ASSERT(tasks_ready);
-	next = __task_id_to_ptr(__fls(tasks_ready));
+	ASSERT(tasks_ready & tasks_enabled);
+	next = __task_id_to_ptr(__fls(tasks_ready & tasks_enabled));
 
 #ifdef CONFIG_TASK_PROFILING
 	/* Track time in interrupts */
@@ -430,9 +432,10 @@ uint32_t task_wait_event_mask(uint32_t event_mask, int timeout_us)
 
 void task_enable_all_tasks(void)
 {
-	/* Mark all tasks as ready to run. */
-	tasks_ready = (1 << TASK_ID_COUNT) - 1;
+	/* Mark all tasks as ready and table to run. */
+	tasks_ready = tasks_enabled = (1 << TASK_ID_COUNT) - 1;
 
+	/* BUG: task_start() was likely already called */
 	start_called = 1;
 
 	/* The host OS driver should wait till the FW completes all hook inits.
diff --git a/core/nds32/task.c b/core/nds32/task.c
index 9310223989..8fab6d1ef8 100644
--- a/core/nds32/task.c
+++ b/core/nds32/task.c
@@ -159,6 +159,12 @@ int need_resched;
  * make a call to enable all tasks.
  */
 static uint32_t tasks_ready = (1 << TASK_ID_HOOKS);
+/*
+ * Initially allow only the HOOKS and IDLE task to run, regardless of ready
+ * status, in order for HOOK_INIT to complete before other tasks.
+ * task_enable_all_tasks() will open the flood gates.
+ */
+static uint32_t tasks_enabled = (1 << TASK_ID_HOOKS) | (1 << TASK_ID_IDLE);
 
 static int start_called;  /* Has task swapping started */
 
@@ -285,7 +291,7 @@ void __ram_code syscall_handler(int desched, task_id_t resched, int swirq)
 
 task_ *next_sched_task(void)
 {
-	task_ *new_task = __task_id_to_ptr(__fls(tasks_ready));
+	task_ *new_task = __task_id_to_ptr(__fls(tasks_ready & tasks_enabled));
 
 #ifdef CONFIG_TASK_PROFILING
 	if (current_task != new_task) {
@@ -526,8 +532,8 @@ void set_int_ctrl(uint32_t val)
 
 void task_enable_all_tasks(void)
 {
-	/* Mark all tasks are ready to run. */
-	tasks_ready = (1 << TASK_ID_COUNT) - 1;
+	/* Mark all tasks as ready and able to run. */
+	tasks_ready = tasks_enabled = (1 << TASK_ID_COUNT) - 1;
 	/* Reschedule the highest priority task. */
 	__schedule(0, 0, 0);
 }
diff --git a/power/common.c b/power/common.c
index c9f58e92db..acca62c6df 100644
--- a/power/common.c
+++ b/power/common.c
@@ -359,8 +359,7 @@ void chipset_exit_hard_off(void)
 	 * pressed. For other states here, to wake the chipset task to trigger
 	 * the event for leaving G3 is necessary.
 	 */
-	if (task_start_called())
-		task_wake(TASK_ID_CHIPSET);
+	task_wake(TASK_ID_CHIPSET);
 }
 
 /*****************************************************************************/