timekeeper: redo timekeeping

kernel-src/include/kernel/timekeeper.h

@@ -2,9 +2,40 @@
 #define _TIMEKEEPER_H
 
 #include <time.h>
+#include <stdbool.h>
 
-void timekeeper_init(time_t (*tick)(), time_t ticksperus);
-timespec_t timekeeper_timefromboot();
-timespec_t timekeeper_time();
+#define TIMEKEEPER_SOURCE_FLAGS_EARLY 1 // can be used as an early timer
+
+typedef struct {
+	time_t ticks_per_us;
+	void *private;
+} timekeeper_source_info_t;
+
+typedef struct {
+	const char *name;
+	int priority;
+	bool (*probe)(void); // returns true if the timer can currently be used
+	timekeeper_source_info_t *(*init)(void); // initializes the timer, returning the info structure
+	time_t (*ticks)(timekeeper_source_info_t *private); // returns a monotonic number of ticks
+	int flags;
+} timekeeper_source_t;
+
+// initializes the highest priority source that can be used as an early timer and switches the cpu to use it
+void timekeeper_early_init(time_t us_offset);
+
+// initializes the highest priority source and switches the cpu to use it. uses the early timer for calibration if nescessary
+void timekeeper_init(void);
+
+// spins waiting for us to pass
+void timekeeper_wait_us(time_t us);
+
+timespec_t timekeeper_timefromboot(void);
+timespec_t timekeeper_time(void);
+
+#define TIMEKEEPER_SOURCE(x, ...) \
+	static timekeeper_source_t x = { \
+		__VA_ARGS__ \
+	}; \
+	__attribute__((section(".timekeeper_sources"), used)) static timekeeper_source_t *timekeeper_source_##x = &x;
 
 #endif

kernel-src/include/mutex.h

@@ -20,4 +20,6 @@ typedef semaphore_t mutex_t;
 #define MUTEX_TRY(m) \
 	semaphore_test(m)
 
+#define MUTEX_DEFINE(x) SEMAPHORE_DEFINE(x, 1)
+
 #endif

kernel-src/include/semaphore.h

@@ -23,6 +23,11 @@ typedef struct semaphore_t{
 		(x)->head = NULL; \
 	}
 
+#define SEMAPHORE_DEFINE(x, v) semaphore_t x = { \
+	.i = v, \
+	.lock = SPINLOCK_INIT_VALUE \
+	}
+
 
 int semaphore_wait(semaphore_t *sem, bool interruptible);
 int semaphore_timedwait(semaphore_t *sem, time_t timeoutusec, bool interruptible);

kernel-src/include/spinlock.h

@@ -7,6 +7,7 @@
 typedef int spinlock_t;
 
 #define SPINLOCK_INIT(x) x = 0;
+#define SPINLOCK_INIT_VALUE 0
 
 static inline void spinlock_acquire(spinlock_t *lock){
 	while(!__sync_bool_compare_and_swap(lock, 0, 1)) asm("pause");

kernel-src/include/time.h

@@ -2,6 +2,7 @@
 #define _TIME_H
 
 #include <util.h>
+#include <stdbool.h>
 
 typedef long time_t;
 typedef long suseconds_t;
@@ -39,4 +40,21 @@ static inline time_t timespec_ns(timespec_t a) {
 	return a.ns + a.s * 1000000000;
 }
 
+static inline time_t timespec_us(timespec_t a) {
+	return a.ns / 1000 + a.s * 1000000;
+}
+
+static inline timespec_t timespec_from_us(time_t us) {
+	timespec_t ts = {
+		.s = us / 1000000,
+		.ns = (us % 1000000) * 100
+	};
+
+	return ts;
+}
+
+static inline bool timespec_bigger(timespec_t t1, timespec_t t2) {
+	return t1.s > t2.s || (t1.s == t2.s && t1.ns > t2.ns);
+}
+
 #endif

kernel-src/include/x86-64/arch/cpu.h

@@ -12,6 +12,7 @@
 #include <kernel/scheduler.h>
 #include <kernel/dpc.h>
 #include <arch/apic.h>
+#include <kernel/timekeeper.h>
 
 #define ARCH_EOI arch_apic_eoi
 
@@ -23,7 +24,12 @@ typedef struct cpu_t {
 
 	vmmcontext_t *vmmctx; // expected to be here by other code
 
-	long id;
+	long id; // expected to be here by other code
+
+	timekeeper_source_t *timekeeper_source;
+	timekeeper_source_info_t *timekeeper_source_info;
+	time_t timekeeper_source_base_ticks;
+	time_t timekeeper_source_tick_offset;
 
 	isr_t isr[MAX_ISR_COUNT];
 	bool intstatus;