diff --git a/security/sandbox/common/test/SandboxTestingChild.cpp b/security/sandbox/common/test/SandboxTestingChild.cpp
index 68d5f8356944..be68b2ba4635 100644
--- a/security/sandbox/common/test/SandboxTestingChild.cpp
+++ b/security/sandbox/common/test/SandboxTestingChild.cpp
@@ -13,6 +13,7 @@
 #  include <fcntl.h>
 #  include <sys/stat.h>
 #  include <sys/types.h>
+#  include <time.h>
 #  include <unistd.h>
 #endif
 
@@ -70,16 +71,25 @@ void SandboxTestingChild::Bind(Endpoint<PSandboxTestingChild>&& aEndpoint) {
     ErrnoTest("fstatat_as_lstat"_ns, true, [&] {
       return fstatat(AT_FDCWD, kAllowedPath, &st, AT_SYMLINK_NOFOLLOW);
     });
+
 #  ifdef XP_LINUX
     ErrnoTest("fstatat_as_fstat"_ns, true,
               [&] { return fstatat(0, "", &st, AT_EMPTY_PATH); });
 #  endif  // XP_LINUX
-#else     // XP_UNIX
+
+    const struct timespec usec = {0, 1000};
+    ErrnoTest("nanosleep"_ns, true, [&] { return nanosleep(&usec, nullptr); });
+
+    struct timespec res = {0, 0};
+    ErrnoTest("clock_getres"_ns, true,
+              [&] { return clock_getres(CLOCK_REALTIME, &res); });
+
+#else   // XP_UNIX
     SendReportTestResults("dummy_test"_ns,
                           /* shouldSucceed */ true,
                           /* didSucceed */ true,
                           "The test framework fails if there are no cases."_ns);
-#endif    // XP_UNIX
+#endif  // XP_UNIX
   }
 
   // Tell SandboxTest that this process is done with all tests.
diff --git a/security/sandbox/linux/SandboxFilter.cpp b/security/sandbox/linux/SandboxFilter.cpp
index b25e6eaa243a..9fddcf0e6d16 100644
--- a/security/sandbox/linux/SandboxFilter.cpp
+++ b/security/sandbox/linux/SandboxFilter.cpp
@@ -619,12 +619,19 @@ class SandboxPolicyCommon : public SandboxPolicyBase {
 
     switch (sysno) {
         // Timekeeping
-      case __NR_clock_nanosleep:
-      case __NR_clock_getres:
-#ifdef __NR_clock_gettime64
-      case __NR_clock_gettime64:
+        //
+        // (Note: the switch needs to start with a literal case, not a
+        // macro; otherwise clang-format gets confused.)
+      case __NR_gettimeofday:
+#ifdef __NR_time
+      case __NR_time:
 #endif
-      case __NR_clock_gettime: {
+      case __NR_nanosleep:
+        return Allow();
+
+      CASES_FOR_clock_gettime:
+      CASES_FOR_clock_getres:
+      CASES_FOR_clock_nanosleep : {
         // clockid_t can encode a pid or tid to monitor another
         // process or thread's CPU usage (see CPUCLOCK_PID and related
         // definitions in include/linux/posix-timers.h in the kernel
@@ -645,15 +652,8 @@ class SandboxPolicyCommon : public SandboxPolicyBase {
             .Else(InvalidSyscall());
       }
 
-      case __NR_gettimeofday:
-#ifdef __NR_time
-      case __NR_time:
-#endif
-      case __NR_nanosleep:
-        return Allow();
-
         // Thread synchronization
-      case __NR_futex:
+      CASES_FOR_futex:
         // FIXME(bug 1441993): This could be more restrictive.
         return Allow();
 
diff --git a/security/sandbox/linux/SandboxFilterUtil.h b/security/sandbox/linux/SandboxFilterUtil.h
index 526dce07dfc6..367a0964bdfc 100644
--- a/security/sandbox/linux/SandboxFilterUtil.h
+++ b/security/sandbox/linux/SandboxFilterUtil.h
@@ -156,24 +156,52 @@ class SandboxPolicyBase : public sandbox::bpf_dsl::Policy {
 #  define CASES_FOR_sigreturn case __NR_rt_sigreturn
 #endif
 
+#ifdef __NR_clock_gettime64
+#  define CASES_FOR_clock_gettime \
+    case __NR_clock_gettime:      \
+    case __NR_clock_gettime64
+#  define CASES_FOR_clock_getres \
+    case __NR_clock_getres:      \
+    case __NR_clock_getres_time64
+#  define CASES_FOR_clock_nanosleep \
+    case __NR_clock_nanosleep:      \
+    case __NR_clock_nanosleep_time64
+#  define CASES_FOR_pselect6 \
+    case __NR_pselect6:      \
+    case __NR_pselect6_time64
+#  define CASES_FOR_ppoll \
+    case __NR_ppoll:      \
+    case __NR_ppoll_time64
+#  define CASES_FOR_futex \
+    case __NR_futex:      \
+    case __NR_futex_time64
+#else
+#  define CASES_FOR_clock_gettime case __NR_clock_gettime
+#  define CASES_FOR_clock_getres case __NR_clock_getres
+#  define CASES_FOR_clock_nanosleep case __NR_clock_nanosleep
+#  define CASES_FOR_pselect6 case __NR_pselect6
+#  define CASES_FOR_ppoll case __NR_ppoll
+#  define CASES_FOR_futex case __NR_futex
+#endif
+
 #if defined(__NR__newselect)
 #  define CASES_FOR_select \
     case __NR__newselect:  \
-    case __NR_pselect6
+      CASES_FOR_pselect6
 #elif defined(__NR_select)
 #  define CASES_FOR_select \
     case __NR_select:      \
-    case __NR_pselect6
+      CASES_FOR_pselect6
 #else
-#  define CASES_FOR_select case __NR_pselect6
+#  define CASES_FOR_select CASES_FOR_pselect6
 #endif
 
 #ifdef __NR_poll
 #  define CASES_FOR_poll \
     case __NR_poll:      \
-    case __NR_ppoll
+      CASES_FOR_ppoll
 #else
-#  define CASES_FOR_poll case __NR_ppoll
+#  define CASES_FOR_poll CASES_FOR_ppoll
 #endif
 
 #ifdef __NR_epoll_create