Kernel/riscv64: Implement Processor::read_cpu_counter

This simply reads the current cycle count from the cycle CSR.
x86-64 uses the similar rdtsc instruction here, which also may or may
not tick at a constant rate.
This commit is contained in:
Sönke Holz 2024-04-21 12:55:36 +02:00 committed by Andrew Kaster
parent c57e39d52b
commit 511e411def
Notes: sideshowbarker 2024-07-16 23:59:28 +09:00
2 changed files with 2 additions and 1 deletions

View file

@ -30,6 +30,7 @@ enum class Address : u16 {
SATP = 0x180,
// Unprivileged Counters/Timers
CYCLE = 0xc00,
TIME = 0xc01,
};

View file

@ -211,7 +211,7 @@ ALWAYS_INLINE void ProcessorBase<T>::wait_check()
template<typename T>
ALWAYS_INLINE u64 ProcessorBase<T>::read_cpu_counter()
{
TODO_RISCV64();
return RISCV64::CSR::read(RISCV64::CSR::Address::CYCLE);
}
}