diff --git a/libc/bionic/sysconf.cpp b/libc/bionic/sysconf.cpp
index 2442fd9..2b3200c 100644
--- a/libc/bionic/sysconf.cpp
+++ b/libc/bionic/sysconf.cpp
@@ -221,9 +221,7 @@
     case _SC_LEVEL4_CACHE_LINESIZE:   return 0;
 
     default:
-      // Posix says EINVAL is the only error that shall be returned,
-      // but glibc uses ENOSYS.
-      errno = ENOSYS;
+      errno = EINVAL;
       return -1;
   }
 }