- unsigned long long ret;
- unsigned eax, edx;
-
- /*
- * Use RDTSCP if possible; it is guaranteed to be synchronous
- * and doesn't cause a VMEXIT on Hypervisors
- */
- alternative_io(ASM_NOP3, ".byte 0x0f,0x01,0xf9", X86_FEATURE_RDTSCP,
- ASM_OUTPUT2("=a" (eax), "=d" (edx)),
- "a" (0U), "d" (0U) : "ecx", "memory");
- ret = (((unsigned long long)edx) << 32) | ((unsigned long long)eax);
- if (ret)
- return ret;
-