diff --git a/libc/include/bits/posix_limits.h b/libc/include/bits/posix_limits.h
index 1bd87f4..c498c69 100644
--- a/libc/include/bits/posix_limits.h
+++ b/libc/include/bits/posix_limits.h
@@ -32,13 +32,13 @@
 #include <sys/cdefs.h>
 
 /* Any constant values here other than -1 or 200809L are explicitly specified by POSIX.1-2008. */
-/* Keep it sorted. */
+/* Keep this list sorted by name. */
 #define _POSIX_ADVISORY_INFO        200809L
 #define _POSIX_AIO_LISTIO_MAX       2
 #define _POSIX_AIO_MAX              1
 #define _POSIX_ARG_MAX              4096
 #define _POSIX_ASYNCHRONOUS_IO      -1  /* not implemented */
-#define _POSIX_BARRIERS             -1  /* not implemented */
+#define _POSIX_BARRIERS             200809L
 #define _POSIX_CHILD_MAX            25
 #define _POSIX_CHOWN_RESTRICTED     1  /* yes, chown requires appropriate privileges */
 #define _POSIX_CLOCK_SELECTION      200809L
@@ -81,7 +81,7 @@
 #define _POSIX_SHELL                1   /* system() supported */
 #define _POSIX_SIGQUEUE_MAX         32
 #define _POSIX_SPAWN                -1  /* not implemented */
-#define _POSIX_SPIN_LOCKS           -1  /* not implemented */
+#define _POSIX_SPIN_LOCKS           200809L
 #define _POSIX_SPORADIC_SERVER      -1  /* not implemented */
 #define _POSIX_SSIZE_MAX            32767
 #define _POSIX_STREAM_MAX           8
diff --git a/tests/unistd_test.cpp b/tests/unistd_test.cpp
index 6299469..80ebf6b 100644
--- a/tests/unistd_test.cpp
+++ b/tests/unistd_test.cpp
@@ -559,6 +559,8 @@
   EXPECT_GT(_POSIX_AIO_LISTIO_MAX, 0);
   EXPECT_GT(_POSIX_AIO_MAX, 0);
   EXPECT_GT(_POSIX_ARG_MAX, 0);
+  EXPECT_GT(_POSIX_BARRIERS, 0);
+  EXPECT_GT(_POSIX_SPIN_LOCKS, 0);
   EXPECT_GT(_POSIX_CHILD_MAX, 0);
   EXPECT_NE(_POSIX_CHOWN_RESTRICTED, -1);
   EXPECT_EQ(_POSIX_VERSION, _POSIX_CLOCK_SELECTION);
@@ -647,12 +649,10 @@
   // These tests only pass on bionic, as bionic and glibc has different support on these macros.
   // Macros like _POSIX_ASYNCHRONOUS_IO are not supported on bionic yet.
   EXPECT_EQ(-1, _POSIX_ASYNCHRONOUS_IO);
-  EXPECT_EQ(-1, _POSIX_BARRIERS);
   EXPECT_EQ(-1, _POSIX_MESSAGE_PASSING);
   EXPECT_EQ(-1, _POSIX_PRIORITIZED_IO);
   EXPECT_EQ(-1, _POSIX_SHARED_MEMORY_OBJECTS);
   EXPECT_EQ(-1, _POSIX_SPAWN);
-  EXPECT_EQ(-1, _POSIX_SPIN_LOCKS);
   EXPECT_EQ(-1, _POSIX_THREAD_PROCESS_SHARED);
   EXPECT_EQ(-1, _POSIX_THREAD_ROBUST_PRIO_INHERIT);
 
@@ -692,6 +692,7 @@
 TEST(UNISTD_TEST, sysconf) {
   VERIFY_SYSCONF_POSIX_VERSION(_SC_ADVISORY_INFO);
   VERIFY_SYSCONF_POSITIVE(_SC_ARG_MAX);
+  VERIFY_SYSCONF_POSIX_VERSION(_SC_BARRIERS);
   VERIFY_SYSCONF_POSITIVE(_SC_BC_BASE_MAX);
   VERIFY_SYSCONF_POSITIVE(_SC_BC_DIM_MAX);
   VERIFY_SYSCONF_POSITIVE(_SC_BC_SCALE_MAX);
@@ -731,6 +732,7 @@
   VERIFY_SYSCONF_POSITIVE(_SC_RTSIG_MAX);
   VERIFY_SYSCONF_POSITIVE(_SC_SEM_NSEMS_MAX);
   VERIFY_SYSCONF_POSITIVE(_SC_SEM_VALUE_MAX);
+  VERIFY_SYSCONF_POSIX_VERSION(_SC_SPIN_LOCKS);
   VERIFY_SYSCONF_POSITIVE(_SC_TIMER_MAX);
   VERIFY_SYSCONF_POSIX_VERSION(_SC_FSYNC);
   VERIFY_SYSCONF_POSIX_VERSION(_SC_MAPPED_FILES);
@@ -810,12 +812,10 @@
   // Tests can only run on bionic, as bionic and glibc have different support for these options.
   // Below options are not supported on bionic yet.
   VERIFY_SYSCONF_UNSUPPORTED(_SC_ASYNCHRONOUS_IO);
-  VERIFY_SYSCONF_UNSUPPORTED(_SC_BARRIERS);
   VERIFY_SYSCONF_UNSUPPORTED(_SC_MESSAGE_PASSING);
   VERIFY_SYSCONF_UNSUPPORTED(_SC_PRIORITIZED_IO);
   VERIFY_SYSCONF_UNSUPPORTED(_SC_SHARED_MEMORY_OBJECTS);
   VERIFY_SYSCONF_UNSUPPORTED(_SC_SPAWN);
-  VERIFY_SYSCONF_UNSUPPORTED(_SC_SPIN_LOCKS);
   VERIFY_SYSCONF_UNSUPPORTED(_SC_THREAD_PROCESS_SHARED);
   VERIFY_SYSCONF_UNSUPPORTED(_SC_THREAD_ROBUST_PRIO_INHERIT);
   VERIFY_SYSCONF_UNSUPPORTED(_SC_THREAD_ROBUST_PRIO_PROTECT);