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authorChristian Cunningham <cc@localhost>2022-01-06 23:20:04 -0800
committerChristian Cunningham <cc@localhost>2022-01-06 23:20:04 -0800
commitaa8d179b2df2ce031a84172a70be88697dfda7c4 (patch)
tree3130a3c0e2bb43759fbfd219e7d71031a94b43fe /src/sys/schedule.c
parent159ba190d626f049512c3ebda70772c03e6737a7 (diff)
Rewrote scheduler in Assembly
Diffstat (limited to 'src/sys/schedule.c')
-rw-r--r--src/sys/schedule.c120
1 files changed, 80 insertions, 40 deletions
diff --git a/src/sys/schedule.c b/src/sys/schedule.c
index 1bb02c2..4b071c3 100644
--- a/src/sys/schedule.c
+++ b/src/sys/schedule.c
@@ -1,3 +1,4 @@
+#include <cpu/irq.h>
#include <drivers/uart.h>
#include <sys/core.h>
#include <sys/schedule.h>
@@ -15,6 +16,12 @@ struct Scheduler scheduler = {
},
.rthread_ll = 0,
};
+unsigned long syssp = 0;
+struct cpu_context syscpu = {
+ .r4 = 0, .r5 = 0, .r6 = 0, .r7 = 0,
+ .r8 = 0, .r9 = 0, .r10 = 0, .r11 = 0,
+ .r12 = 0, .lr = 0,
+};
void init_scheduler(void)
{
@@ -24,6 +31,7 @@ void init_scheduler(void)
scheduler.tlist[i].data = 0;
}
scheduler.rthread_ll = 0;
+ scheduler.ctx = &syscpu;
}
unsigned char stacks_table[MAX_THREADS] = {0, };
@@ -42,12 +50,12 @@ void* get_stack(void)
static unsigned long nextpid = 3;
void add_thread(void (*thread_fxn)(void), unsigned char priority)
{
- struct Thread* thread = (struct Thread*)malloc(sizeof(struct Thread));
+ struct Thread* thread = (struct Thread*)malloca(sizeof(struct Thread), 4);
// Set the program counter to the entry
thread->thread = thread_fxn;
// Get a stack frame
- thread->stack = get_stack();
- thread->stack_base = thread->stack;
+ thread->stack_base = get_stack();
+ thread->stack = thread->stack_base;
// Put in error state for no stack
if(thread->stack == 0)
thread->data.status = THREAD_STACK_ERROR;
@@ -57,6 +65,8 @@ void add_thread(void (*thread_fxn)(void), unsigned char priority)
thread->data.mutex_waiting = 0;
// Set PID
thread->data.pid = nextpid++;
+ thread->data.preempt_count = 0;
+ thread->data.cpu_context.lr = (unsigned long)cleanup;
unsigned char p = priority;
if (p >= PRIORITIES) {
p = PRIORITIES - 1;
@@ -81,70 +91,100 @@ struct LL* get_next_thread(void)
return 0;
}
-unsigned long syssp = 0;
-void schedule(void)
+void schedule_c(void)
{
- // Preserve current process's registers
- // in the current stack
- asm volatile ("push {r0, r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12, lr}");
+ // Preserve registers in current context
+ preserve_ctx(scheduler.ctx);
+
// Get current thread
struct LL* current_thread_ll = scheduler.rthread_ll;
// Get next thread
struct LL* next_thread_ll = get_next_thread();
// If there is a current thread
- if (current_thread_ll) {
+ if (current_thread_ll != 0) {
// If we are switching the thread
if (current_thread_ll != next_thread_ll) {
// Context switch
struct Thread* current_thread = current_thread_ll->data;
struct Thread* next_thread = next_thread_ll->data;
- preservestack(current_thread);
- preservepc(current_thread);
- restorestack(next_thread);
- //restoreregs(next_thread);
+ preserve_stack(current_thread);
+ //preserve_pc(current_thread);
+ current_thread->thread = (void*)current_thread->data.cpu_context.lr;
+ restore_stack(next_thread);
scheduler.rthread_ll = next_thread_ll;
+ scheduler.ctx = &next_thread->data.cpu_context;
}
}
- else if (next_thread_ll) {
+ else if (next_thread_ll != 0) {
struct Thread* next_thread = next_thread_ll->data;
- preservesysstack(&syssp);
- //preservesysregs(&regloc)
- restorestack(next_thread);
- //restoreregs(next_thread);
+ preserve_sys_stack(&syssp);
+ restore_stack(next_thread);
scheduler.rthread_ll = next_thread_ll;
+ scheduler.ctx = &next_thread->data.cpu_context;
}
if (scheduler.rthread_ll) {
struct Thread* rthread = scheduler.rthread_ll->data;
- // Restore process's registers
- asm volatile ("pop {r0, r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12, lr}");
- // Run the thread - i.e. jump to the pc
- asm volatile ("blx lr");
- //rthread->thread();
- // Remove the currently running thread after completion
- remove_running_thread();
- // Schedule the next thread
- schedule();
+ restore_ctx(scheduler.ctx);
+ asm volatile ("bx %0" :: "r"(rthread->thread));
} else {
- //restoresysregs(&regloc);
- restoresysstack(&syssp);
+ scheduler.ctx = &syscpu;
+ restore_sys_stack(&syssp);
+ restore_ctx(scheduler.ctx);
}
}
-void remove_running_thread(void)
+void cleanup(void)
{
if (scheduler.rthread_ll != 0) {
+ // Mark the thread as finished
+ struct Thread* t = scheduler.rthread_ll->data;
+ uart_string("Cleaning up thread ");
+ uart_10(t->data.pid);
+ uart_char('\n');
+ t->data.status = THREAD_FINISHED;
+ // Mark the stack space as free
+ unsigned long sidx = (unsigned long)(heap_end() - t->stack_base)/STACK_SIZE;
+ stacks_table[sidx] = 0;
+ // Remove the thread
struct LL* ll = scheduler.rthread_ll;
- if ((ll->next == ll->prev) && (ll->next == ll)) {
- ll->data = 0;
- }
- else {
- struct LL* prev = ll->prev;
- struct LL* next = ll->next;
- prev->next = ll->next;
- next->prev = ll->prev;
- free(ll);
- }
+ struct LL* prev = ll->prev;
+ struct LL* next = ll->next;
+ prev->next = ll->next;
+ next->prev = ll->prev;
+ free(ll);
scheduler.rthread_ll = 0;
}
+ // Schedule next thread
+ //uart_string("Scheduling from cleanup!\n");
+ //sched_info();
+ //schedule();
+ schedule();
+}
+
+void sched_info(void)
+{
+ disableirq();
+ uart_string("Scheduler Information\n");
+ for(unsigned long i = 0; i < PRIORITIES; i++) {
+ struct LL* ll = scheduler.tlist[i].next;
+ uart_string("Queue ");
+ uart_10(i);
+ while (ll != &scheduler.tlist[i]) {
+ uart_string("\nThread ");
+ struct Thread* t = ll->data;
+ uart_hex((unsigned long)t->thread);uart_char(' ');
+ uart_hex((unsigned long)t->stack);uart_char(' ');
+ uart_hex((unsigned long)t->stack_base);uart_char(' ');
+ uart_10(t->data.priority);uart_char(' ');
+ uart_10(t->data.preempt_count);uart_char(' ');
+ uart_10(t->data.status);uart_char(' ');
+ uart_hex((unsigned long)t->data.mutex_waiting);uart_char(' ');
+ uart_10(t->data.pid);uart_char('\n');
+ memshow32((unsigned long*)&t->data.cpu_context, 10);
+ ll = ll->next;
+ }
+ uart_char('\n');
+ }
+ enableirq();
}