arch/x86_64: Fix wrong RDTSCP implementation

RDTSCP instruction reads the current value of the processor’s
time-stamp counter (a 64-bit MSR) into the EDX:EAX registers, and it
also reads the value of the IA32_TSC_AUX MSR (address C0000103H) into
the ECX register. However, the current RDTSCP implementation does not
provide a hint for the compiler that ECX has been changed, resulting in
register corrupted and subtle errors.

Signed-off-by: ouyangxiangzhen <[email protected]>

Author: Fix-Point

arch/x86_64/include/intel64/irq.h

@@ -535,7 +535,7 @@ static inline uint64_t rdtscp(void)
   uint32_t lo;
   uint32_t hi;
 
-  asm volatile("rdtscp" : "=a" (lo), "=d" (hi)::"memory");
+  asm volatile("rdtscp" : "=a" (lo), "=d" (hi)::"ecx", "memory");
   return (uint64_t)lo | (((uint64_t)hi) << 32);
 }