kernel: OS uptime is now using RTC + getter for CPU freq

api/kernel/os.hpp

@@ -29,6 +29,7 @@
 #include <hw/cpu.hpp>
 #include <hertz>
 #include <vector>
+#include <kernel/rtc.hpp>
 
 namespace hw{ class Serial; }
 
@@ -55,11 +56,18 @@ class OS {
     return cycles_since_boot() / cpu_mhz_.count();
   }
 
-  /** Uptime in seconds. */
-  static double uptime() {
-    return cycles_since_boot() / Hz(cpu_mhz_).count();
+  /** Timestamp for when OS was booted */
+  static RTC::timestamp_t boot_timestamp()
+  { return booted_at_; }
+
+  /** Uptime in whole seconds. */
+  static RTC::timestamp_t uptime() {
+    return RTC::now() - booted_at_;
   }
 
+  static MHz cpu_freq()
+  { return cpu_mhz_; }
+
   /**
    * Shutdown operating system
    *
@@ -159,6 +167,8 @@ class OS {
 
   static hw::Serial& com1;
 
+  static RTC::timestamp_t booted_at_;
+
 
   struct Custom_init_struct {
     Custom_init_struct(Custom_init f, const char* n)

api/kernel/rtc.hpp

@@ -28,10 +28,7 @@ class RTC
   using timestamp_t = int64_t;
 
   /// returns a 64-bit unix timestamp of the current time
-  static timestamp_t get();
-
-  static timestamp_t now()
-  { return get(); }
+  static timestamp_t now();
 
   /// start an auto-calibration process
   static void init();

src/kernel/os.cpp

@@ -46,6 +46,7 @@ extern uintptr_t _MAX_MEM_MIB_;
 
 bool OS::power_   {true};
 MHz  OS::cpu_mhz_ {1000};
+RTC::timestamp_t OS::booted_at_ {0};
 uintptr_t OS::low_memory_size_ {0};
 uintptr_t OS::high_memory_size_ {0};
 uintptr_t OS::heap_max_ {0xfffffff};
@@ -215,6 +216,7 @@ void OS::start(uint32_t boot_magic, uint32_t boot_addr) {
 
   // Realtime/monotonic clock
   RTC::init();
+  booted_at_ = RTC::now();
 
   // Trying custom initialization functions
   MYINFO("Calling custom initialization functions");

src/kernel/rtc.cpp

@@ -28,10 +28,10 @@ void RTC::init()
   });
 }
 
-RTC::timestamp_t RTC::get()
+RTC::timestamp_t RTC::now()
 {
   auto ticks = hw::CPU::rdtsc() - current_ticks;
   auto diff  = ticks / Hz(MHz(_CPUFreq_)).count();
-  
+
   return current_time + diff;
 }

src/kernel/syscalls.cpp

@@ -149,7 +149,7 @@ int wait(int* UNUSED(status)) {
 }
 
 int gettimeofday(struct timeval* p, void*) {
-  p->tv_sec  = RTC::get();
+  p->tv_sec  = RTC::now();
   p->tv_usec = 0;
   return 0;
 }
@@ -212,7 +212,7 @@ void abort_ex(const char* why) {
 // Basic second-resolution implementation - using CMOS directly for now.
 int clock_gettime(clockid_t clk_id, struct timespec *tp){
   if (clk_id == CLOCK_REALTIME) {
-    tp->tv_sec = RTC::get();
+    tp->tv_sec = RTC::now();
     tp->tv_nsec = 0;
     return 0;
   }