x86: add inline CPUID instruction

arch/x86/include/arch/cpufunc.h

@@ -74,6 +74,22 @@ static __always_inline void halt(void)
 	__asm__ volatile("hlt");
 }
 
+struct x86_cpuid_ret {
+	u32 eax;
+	u32 ebx;
+	u32 ecx;
+	u32 edx;
+};
+
+static inline void x86_cpuid(struct x86_cpuid_ret *ret, u32 eax, u32 ecx)
+{
+	__asm__ volatile(
+	"cpuid"
+	: "=a"(ret->eax), "=b"(ret->ebx), "=c"(ret->ecx), "=d"(ret->edx)
+	: "0"(eax), "c"(ecx)
+	);
+}
+
 static __always_inline void x86_pause(void)
 {
 	__asm__ volatile("pause");