derp. raw-syscalls

core/sys/unix/syscalls_linux.odin

@@ -1537,7 +1537,6 @@ MAP_SHARED          :: 0x1
 MAP_PRIVATE         :: 0x2
 MAP_SHARED_VALIDATE :: 0x3
 MAP_ANONYMOUS       :: 0x20
-MAP_FAILED          :: -1
 
 // mremap flags
 MREMAP_MAYMOVE   :: 1

core/time/tsc_linux.odin

@@ -25,7 +25,7 @@ _get_tsc_frequency :: proc "contextless" () -> u64 {
 
 	page_size : uint = 4096
 	ret := unix.sys_mmap(nil, page_size, unix.PROT_READ, unix.MAP_SHARED, fd, 0)
-	if ret == unix.MAP_FAILED {
+	if ret < 0 && > -4096 {
 		frequency = 1
 		return 0
 	}