riscv: Implement CPU counter

Update #3433.

1 files changed, 16 insertions, 1 deletions

diff --git a/cpukit/score/cpu/riscv/include/rtems/score/cpu.h b/cpukit/score/cpu/riscv/include/rtems/score/cpu.h
index e79ce25510..f84395c638 100644
--- a/cpukit/score/cpu/riscv/include/rtems/score/cpu.h
+++ b/cpukit/score/cpu/riscv/include/rtems/score/cpu.h
@@ -370,7 +370,22 @@ typedef uint32_t CPU_Counter_ticks;
 
 uint32_t _CPU_Counter_frequency( void );
 
-CPU_Counter_ticks _CPU_Counter_read( void );
+static inline CPU_Counter_ticks _CPU_Counter_read( void )
+{
+  unsigned long ticks;
+
+  __asm__ volatile ( "rdtime %0" : "=&r" ( ticks ) );
+
+  return (uint32_t) ticks;
+}
+
+static inline CPU_Counter_ticks _CPU_Counter_difference(
+  CPU_Counter_ticks second,
+  CPU_Counter_ticks first
+)
+{
+  return second - first;
+}
 
 #ifdef RTEMS_SMP