diff options
author | Randall Spangler <rspangler@chromium.org> | 2012-09-07 11:10:27 -0700 |
---|---|---|
committer | Gerrit <chrome-bot@google.com> | 2012-09-09 10:33:49 -0700 |
commit | d66ef1213dc1fa015ffc7458ab9d67a669a326bc (patch) | |
tree | f7f701062d6fcb993b2dcc4215f1bf56d9276d4d /core/cortex-m | |
parent | b35ad52db3dcc5441b948499e06f9ad773aff0c5 (diff) | |
download | chrome-ec-d66ef1213dc1fa015ffc7458ab9d67a669a326bc.tar.gz |
Track current task directly instead of computing from stack pointer
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>
Diffstat (limited to 'core/cortex-m')
-rw-r--r-- | core/cortex-m/task.c | 57 | ||||
-rw-r--r-- | core/cortex-m/watchdog.c | 2 |
2 files changed, 14 insertions, 45 deletions
diff --git a/core/cortex-m/task.c b/core/cortex-m/task.c index 76e6275ec4..e498301362 100644 --- a/core/cortex-m/task.c +++ b/core/cortex-m/task.c @@ -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" diff --git a/core/cortex-m/watchdog.c b/core/cortex-m/watchdog.c index 3ad89e94ab..d21bb4f1ec 100644 --- a/core/cortex-m/watchdog.c +++ b/core/cortex-m/watchdog.c @@ -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(); |