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Track current task directly instead of computing from stack pointer

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This is a precursor to supporting task-specific task sizes.  I've
benchmarked this vs. the current stack pointer method; no measurable
performance difference.

BUG=chrome-os-partner:13814
TEST=boot EC; taskinfo; if it boots and doesn't print garbage, it worked
BRANCH=all

Change-Id: Ia326c3ab499ac03cce78dbacaa52f735601a171e
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/32603
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
This commit is contained in:
Randall Spangler
2012-09-07 11:10:27 -07:00
committed by Gerrit
parent b35ad52db3
commit d66ef1213d
3 changed files with 15 additions and 53 deletions
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57
core/cortex-m/task.c
View File

@@ -19,8 +19,7 @@
* Global memory size for a task : 512 bytes
* including its contexts and its stack
*/
#define TASK_SIZE_LOG2 9
#define TASK_SIZE (1<<TASK_SIZE_LOG2)
#define TASK_SIZE 512
typedef union {
struct {
@@ -124,6 +123,8 @@ static task_ tasks[TASK_ID_COUNT] __attribute__((section(".bss.tasks")))
* in its own section which immediately follows .bss.tasks in ec.lds.S. */
uint32_t scratchpad[17] __attribute__((section(".bss.task_scratchpad")));
static task_ *current_task = (task_ *)scratchpad;
/* Should IRQs chain to svc_handler()? This should be set if either of the
* following is true:
*
@@ -144,30 +145,6 @@ static uint32_t tasks_ready = (1<<TASK_ID_COUNT) - 1;
static int start_called; /* Has task swapping started */
static task_ *__get_current(void)
{
unsigned sp;
asm("mov %0, sp":"=r"(sp));
return (task_ *)((sp - 4) & ~(TASK_SIZE-1));
}
/**
* Return a pointer to the task preempted by the current exception
*
* designed to be called from interrupt context.
*/
static task_ *__get_task_scheduled(void)
{
unsigned sp;
asm("mrs %0, psp":"=r"(sp));
return (task_ *)((sp - 16) & ~(TASK_SIZE-1));
}
static inline task_ *__task_id_to_ptr(task_id_t id)
{
return tasks + id;
@@ -202,23 +179,11 @@ inline int get_interrupt_context(void)
return ret & 0x1ff; /* exception bits are the 9 LSB */
}
task_id_t task_from_addr(uint32_t addr)
{
task_id_t id = (addr - (uint32_t)tasks) >> TASK_SIZE_LOG2;
if (id >= TASK_ID_COUNT)
id = TASK_ID_INVALID;
return id;
}
task_id_t task_get_current(void)
{
return task_from_addr((uint32_t)__get_current());
return current_task - tasks;
}
uint32_t *task_get_event_bitmap(task_id_t tskid)
{
task_ *tsk = __task_id_to_ptr(tskid);
@@ -255,14 +220,17 @@ void svc_handler(int desched, task_id_t resched)
}
#endif
current = __get_task_scheduled();
current = current_task;
#ifdef CONFIG_OVERFLOW_DETECT
ASSERT(current->guard == GUARD_VALUE);
#endif
if (desched && !current->events) {
/* Remove our own ready bit */
tasks_ready &= ~(1 << (current-tasks));
/*
* Remove our own ready bit (current - tasks is same as
* task_get_current())
*/
tasks_ready &= ~(1 << (current - tasks));
}
tasks_ready |= 1 << resched;
@@ -292,6 +260,7 @@ void svc_handler(int desched, task_id_t resched)
#ifdef CONFIG_TASK_PROFILING
task_switches++;
#endif
current_task = next;
__switchto(current, next);
}
@@ -343,7 +312,7 @@ void task_resched_if_needed(void *excep_return)
static uint32_t __wait_evt(int timeout_us, task_id_t resched)
{
task_ *tsk = __get_current();
task_ *tsk = current_task;
task_id_t me = tsk - tasks;
uint32_t evt;
int ret;
@@ -488,7 +457,7 @@ void mutex_lock(struct mutex *mtx)
void mutex_unlock(struct mutex *mtx)
{
uint32_t waiters;
task_ *tsk = __get_current();
task_ *tsk = current_task;
__asm__ __volatile__(" ldr %0, [%2]\n"
" str %3, [%1]\n"

2
core/cortex-m/watchdog.c
View File

@@ -34,7 +34,7 @@ void watchdog_trace(uint32_t excep_lr, uint32_t excep_sp)
if ((excep_lr & 0xf) == 1)
uart_puts("(exc) ###\n");
else
uart_printf("(task %d) ###\n", task_from_addr(psp));
uart_printf("(task %d) ###\n", task_get_current());
/* Ensure this debug message is always flushed to the UART */
uart_emergency_flush();

9
include/task.h
View File

@@ -50,16 +50,9 @@ static inline void task_wake(task_id_t tskid)
task_set_event(tskid, TASK_EVENT_WAKE, 0);
}
/* Return the identifier of the task currently running.
*
* When called in interrupt context, returns TASK_ID_INVALID. */
/* Return the identifier of the task currently running. */
task_id_t task_get_current(void);
/* Convert an address to the corresponding task ID. The address may be a stack
* pointer or the task data for a task. Returns TASK_ID_INVALID if the address
* does not correspond to a task. */
task_id_t task_from_addr(uint32_t addr);
/* Return a pointer to the bitmap of events of the task. */
uint32_t *task_get_event_bitmap(task_id_t tsk);