diff --git a/posix/Makefile b/posix/Makefile
index a8fb1e1839..49d7a91b77 100644
--- a/posix/Makefile
+++ b/posix/Makefile
@@ -31,7 +31,8 @@ headers	:= sys/utsname.h sys/times.h sys/wait.h sys/types.h unistd.h	      \
 	   bits/local_lim.h tar.h bits/utsname.h bits/confname.h	      \
 	   bits/waitflags.h bits/waitstatus.h sys/unistd.h sched.h	      \
 	   bits/sched.h bits/cpu-set.h re_comp.h wait.h bits/environments.h   \
-	   cpio.h spawn.h bits/unistd.h bits/types/struct_sched_param.h
+	   cpio.h spawn.h bits/unistd.h bits/types/struct_sched_param.h	      \
+	   bits/unistd_ext.h
 
 routines :=								      \
 	uname								      \
diff --git a/posix/bits/unistd_ext.h b/posix/bits/unistd_ext.h
new file mode 100644
index 0000000000..8019cfa758
--- /dev/null
+++ b/posix/bits/unistd_ext.h
@@ -0,0 +1,21 @@
+/* System-specific extensions of <unistd.h>, generic version.
+   Copyright (C) 2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _UNISTD_H
+# error "Never include <bits/unistd_ext.h> directly; use <unistd.h> instead."
+#endif
diff --git a/posix/unistd.h b/posix/unistd.h
index a8cf28b5e7..127ed494ce 100644
--- a/posix/unistd.h
+++ b/posix/unistd.h
@@ -1166,6 +1166,9 @@ int getentropy (void *__buffer, size_t __length) __wur;
 # include <bits/unistd.h>
 #endif
 
+/* System-specific extensions.  */
+#include <bits/unistd_ext.h>
+
 __END_DECLS
 
 #endif /* unistd.h  */
diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
index 362cf3b950..99884799e6 100644
--- a/sysdeps/unix/sysv/linux/Makefile
+++ b/sysdeps/unix/sysv/linux/Makefile
@@ -48,7 +48,7 @@ sysdep_headers += sys/mount.h sys/acct.h sys/sysctl.h \
 tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \
 	 tst-quota tst-sync_file_range tst-sysconf-iov_max tst-ttyname \
 	 test-errno-linux tst-memfd_create tst-mlock2 tst-pkey \
-	 tst-rlimit-infinity tst-ofdlocks
+	 tst-rlimit-infinity tst-ofdlocks tst-gettid
 tests-internal += tst-ofdlocks-compat
 
 
@@ -100,6 +100,8 @@ $(objpfx)tst-sysconf-iov_max: $(objpfx)tst-sysconf-iov_max-uapi.o
 
 $(objpfx)tst-pkey: $(shared-thread-library)
 
+$(objpfx)tst-gettid: $(shared-thread-library)
+
 endif # $(subdir) == misc
 
 ifeq ($(subdir),time)
diff --git a/sysdeps/unix/sysv/linux/Versions b/sysdeps/unix/sysv/linux/Versions
index 336c13b57d..6b5cd99b51 100644
--- a/sysdeps/unix/sysv/linux/Versions
+++ b/sysdeps/unix/sysv/linux/Versions
@@ -171,6 +171,9 @@ libc {
     mlock2;
     pkey_alloc; pkey_free; pkey_set; pkey_get; pkey_mprotect;
   }
+  GLIBC_2.29 {
+    gettid;
+  }
   GLIBC_PRIVATE {
     # functions used in other libraries
     __syscall_rt_sigqueueinfo;
diff --git a/sysdeps/unix/sysv/linux/aarch64/libc.abilist b/sysdeps/unix/sysv/linux/aarch64/libc.abilist
index e66c741d04..a9851a9450 100644
--- a/sysdeps/unix/sysv/linux/aarch64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/aarch64/libc.abilist
@@ -2138,4 +2138,5 @@ GLIBC_2.28 thrd_current F
 GLIBC_2.28 thrd_equal F
 GLIBC_2.28 thrd_sleep F
 GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
diff --git a/sysdeps/unix/sysv/linux/alpha/libc.abilist b/sysdeps/unix/sysv/linux/alpha/libc.abilist
index 8df162fe99..b9cdd685e4 100644
--- a/sysdeps/unix/sysv/linux/alpha/libc.abilist
+++ b/sysdeps/unix/sysv/linux/alpha/libc.abilist
@@ -2033,6 +2033,7 @@ GLIBC_2.28 thrd_current F
 GLIBC_2.28 thrd_equal F
 GLIBC_2.28 thrd_sleep F
 GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.3 __ctype_b_loc F
 GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/arm/libc.abilist b/sysdeps/unix/sysv/linux/arm/libc.abilist
index 43c804f9dc..958d9d4f2b 100644
--- a/sysdeps/unix/sysv/linux/arm/libc.abilist
+++ b/sysdeps/unix/sysv/linux/arm/libc.abilist
@@ -123,6 +123,7 @@ GLIBC_2.28 thrd_current F
 GLIBC_2.28 thrd_equal F
 GLIBC_2.28 thrd_sleep F
 GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.4 _Exit F
 GLIBC_2.4 _IO_2_1_stderr_ D 0xa0
diff --git a/sysdeps/unix/sysv/linux/bits/unistd_ext.h b/sysdeps/unix/sysv/linux/bits/unistd_ext.h
new file mode 100644
index 0000000000..5f964bca94
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/bits/unistd_ext.h
@@ -0,0 +1,32 @@
+/* System-specific extensions of <unistd.h>, Linux version.
+   Copyright (C) 2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _UNISTD_H
+# error "Never include <bits/unistd_ext.h> directly; use <unistd.h> instead."
+#endif
+
+#ifdef __USE_GNU
+
+/* Return the kernel thread ID (TID) of the current thread.  The
+   returned value is not subject to caching.  Note that a TID uniquely
+   identifies a thread only while this thread is running; a TID can be
+   reused once a thread has exited, even if the thread is not detached
+   and has not been joined.  */
+extern __pid_t gettid (void) __THROW;
+
+#endif
diff --git a/sysdeps/unix/sysv/linux/hppa/libc.abilist b/sysdeps/unix/sysv/linux/hppa/libc.abilist
index 88b01c2e75..ff3656d3bb 100644
--- a/sysdeps/unix/sysv/linux/hppa/libc.abilist
+++ b/sysdeps/unix/sysv/linux/hppa/libc.abilist
@@ -1880,6 +1880,7 @@ GLIBC_2.28 thrd_current F
 GLIBC_2.28 thrd_equal F
 GLIBC_2.28 thrd_sleep F
 GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.3 __ctype_b_loc F
 GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/i386/libc.abilist b/sysdeps/unix/sysv/linux/i386/libc.abilist
index 6d02f31612..9abad3352d 100644
--- a/sysdeps/unix/sysv/linux/i386/libc.abilist
+++ b/sysdeps/unix/sysv/linux/i386/libc.abilist
@@ -2045,6 +2045,7 @@ GLIBC_2.28 thrd_current F
 GLIBC_2.28 thrd_equal F
 GLIBC_2.28 thrd_sleep F
 GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.3 __ctype_b_loc F
 GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/ia64/libc.abilist b/sysdeps/unix/sysv/linux/ia64/libc.abilist
index 4249712611..1c1018e84e 100644
--- a/sysdeps/unix/sysv/linux/ia64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/ia64/libc.abilist
@@ -1914,6 +1914,7 @@ GLIBC_2.28 thrd_current F
 GLIBC_2.28 thrd_equal F
 GLIBC_2.28 thrd_sleep F
 GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.3 __ctype_b_loc F
 GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
index d47b808862..f8f6c42be4 100644
--- a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
+++ b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
@@ -124,6 +124,7 @@ GLIBC_2.28 thrd_current F
 GLIBC_2.28 thrd_equal F
 GLIBC_2.28 thrd_sleep F
 GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.4 _Exit F
 GLIBC_2.4 _IO_2_1_stderr_ D 0x98
diff --git a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
index d5e38308be..8d73f730b7 100644
--- a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
+++ b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
@@ -1989,6 +1989,7 @@ GLIBC_2.28 thrd_current F
 GLIBC_2.28 thrd_equal F
 GLIBC_2.28 thrd_sleep F
 GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.3 __ctype_b_loc F
 GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/microblaze/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/libc.abilist
index 8596b84399..21daf81c03 100644
--- a/sysdeps/unix/sysv/linux/microblaze/libc.abilist
+++ b/sysdeps/unix/sysv/linux/microblaze/libc.abilist
@@ -2130,4 +2130,5 @@ GLIBC_2.28 thrd_current F
 GLIBC_2.28 thrd_equal F
 GLIBC_2.28 thrd_sleep F
 GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
diff --git a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
index 88e0f896d5..0e519f164b 100644
--- a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
@@ -1967,6 +1967,7 @@ GLIBC_2.28 thrd_current F
 GLIBC_2.28 thrd_equal F
 GLIBC_2.28 thrd_sleep F
 GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.3 __ctype_b_loc F
 GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
index aff7462c34..da97eae834 100644
--- a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
@@ -1965,6 +1965,7 @@ GLIBC_2.28 thrd_current F
 GLIBC_2.28 thrd_equal F
 GLIBC_2.28 thrd_sleep F
 GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.3 __ctype_b_loc F
 GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
index 71d82444aa..d522182d71 100644
--- a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
@@ -1973,6 +1973,7 @@ GLIBC_2.28 thrd_current F
 GLIBC_2.28 thrd_equal F
 GLIBC_2.28 thrd_sleep F
 GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.3 __ctype_b_loc F
 GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
index de6c53d293..b284b21f78 100644
--- a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
@@ -1968,6 +1968,7 @@ GLIBC_2.28 thrd_current F
 GLIBC_2.28 thrd_equal F
 GLIBC_2.28 thrd_sleep F
 GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.3 __ctype_b_loc F
 GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/nios2/libc.abilist b/sysdeps/unix/sysv/linux/nios2/libc.abilist
index e724bab9fb..dbbe729e18 100644
--- a/sysdeps/unix/sysv/linux/nios2/libc.abilist
+++ b/sysdeps/unix/sysv/linux/nios2/libc.abilist
@@ -2171,4 +2171,5 @@ GLIBC_2.28 thrd_current F
 GLIBC_2.28 thrd_equal F
 GLIBC_2.28 thrd_sleep F
 GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
index e9ecbccb71..35231739ea 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
@@ -1993,6 +1993,7 @@ GLIBC_2.28 thrd_current F
 GLIBC_2.28 thrd_equal F
 GLIBC_2.28 thrd_sleep F
 GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.3 __ctype_b_loc F
 GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
index da83ea6028..cea0accf60 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
@@ -1997,6 +1997,7 @@ GLIBC_2.28 thrd_current F
 GLIBC_2.28 thrd_equal F
 GLIBC_2.28 thrd_sleep F
 GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.3 __ctype_b_loc F
 GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist
index 4535b40d15..55d2d0c621 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist
@@ -2228,4 +2228,5 @@ GLIBC_2.28 thrd_current F
 GLIBC_2.28 thrd_equal F
 GLIBC_2.28 thrd_sleep F
 GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist
index 65725de4f0..a4962c13a8 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist
@@ -123,6 +123,7 @@ GLIBC_2.28 thrd_current F
 GLIBC_2.28 thrd_equal F
 GLIBC_2.28 thrd_sleep F
 GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.3 _Exit F
 GLIBC_2.3 _IO_2_1_stderr_ D 0xe0
diff --git a/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist b/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
index bbb3c4a8e7..06372f7b97 100644
--- a/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
@@ -2100,4 +2100,5 @@ GLIBC_2.28 thrd_current F
 GLIBC_2.28 thrd_equal F
 GLIBC_2.28 thrd_sleep F
 GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
index e85ac2a178..403f30aa3e 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
@@ -2002,6 +2002,7 @@ GLIBC_2.28 thrd_current F
 GLIBC_2.28 thrd_equal F
 GLIBC_2.28 thrd_sleep F
 GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.3 __ctype_b_loc F
 GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
index d56931022c..c5095fad6f 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
@@ -1908,6 +1908,7 @@ GLIBC_2.28 thrd_equal F
 GLIBC_2.28 thrd_sleep F
 GLIBC_2.28 thrd_yield F
 GLIBC_2.29 __fentry__ F
+GLIBC_2.29 gettid F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.3 __ctype_b_loc F
 GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/sh/libc.abilist b/sysdeps/unix/sysv/linux/sh/libc.abilist
index ff939a15c4..9b4b9328d3 100644
--- a/sysdeps/unix/sysv/linux/sh/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sh/libc.abilist
@@ -1884,6 +1884,7 @@ GLIBC_2.28 thrd_current F
 GLIBC_2.28 thrd_equal F
 GLIBC_2.28 thrd_sleep F
 GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.3 __ctype_b_loc F
 GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
index 64fa9e10a5..5c3480af84 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
@@ -1996,6 +1996,7 @@ GLIBC_2.28 thrd_current F
 GLIBC_2.28 thrd_equal F
 GLIBC_2.28 thrd_sleep F
 GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.3 __ctype_b_loc F
 GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
index db909d1506..2928506213 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
@@ -1937,6 +1937,7 @@ GLIBC_2.28 thrd_current F
 GLIBC_2.28 thrd_equal F
 GLIBC_2.28 thrd_sleep F
 GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.3 __ctype_b_loc F
 GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/syscalls.list b/sysdeps/unix/sysv/linux/syscalls.list
index e24ea29e35..544ab5d54a 100644
--- a/sysdeps/unix/sysv/linux/syscalls.list
+++ b/sysdeps/unix/sysv/linux/syscalls.list
@@ -112,3 +112,4 @@ process_vm_writev EXTRA	process_vm_writev i:ipipii process_vm_writev
 memfd_create    EXTRA	memfd_create	i:si    memfd_create
 pkey_alloc	EXTRA	pkey_alloc	i:ii	pkey_alloc
 pkey_free	EXTRA	pkey_free	i:i	pkey_free
+gettid          EXTRA   gettid          Ei:     __gettid	gettid
diff --git a/sysdeps/unix/sysv/linux/tst-gettid.c b/sysdeps/unix/sysv/linux/tst-gettid.c
new file mode 100644
index 0000000000..78bbaee4f3
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/tst-gettid.c
@@ -0,0 +1,79 @@
+/* Smoke test for the gettid system call.
+   Copyright (C) 2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <support/check.h>
+#include <support/namespace.h>
+#include <support/xthread.h>
+#include <support/xunistd.h>
+
+/* TID of the initial (main) thread.  */
+static pid_t initial_tid;
+
+/* Check that PID and TID are the same in a subprocess.  */
+static void
+subprocess (void *closure)
+{
+  TEST_COMPARE (getpid (), gettid ());
+  TEST_VERIFY (gettid () != initial_tid);
+}
+
+/* Check that the TID changes in a new thread.  */
+static void *
+threadfunc (void *closure)
+{
+  TEST_VERIFY (getpid () != gettid ());
+  TEST_VERIFY (gettid () != initial_tid);
+  return NULL;
+}
+
+/* Check for interactions with vfork.  */
+static void
+test_vfork (void)
+{
+  pid_t proc = vfork ();
+  if (proc == 0)
+    {
+      if (getpid () != gettid ())
+        _exit (1);
+      if (gettid () == initial_tid)
+        _exit (2);
+      _exit (0);
+    }
+  int status;
+  xwaitpid (proc, &status, 0);
+  TEST_COMPARE (status, 0);
+}
+
+static int
+do_test (void)
+{
+  initial_tid = gettid ();
+
+  /* The main thread has the same TID as the PID.  */
+  TEST_COMPARE (getpid (), gettid ());
+
+  test_vfork ();
+
+  support_isolate_in_subprocess (subprocess, NULL);
+
+  xpthread_join (xpthread_create (NULL, threadfunc, NULL));
+
+  return 0;
+}
+
+#include <support/test-driver.c>
diff --git a/sysdeps/unix/sysv/linux/tst-setgetname.c b/sysdeps/unix/sysv/linux/tst-setgetname.c
index b80ff59074..95d8bb9ba4 100644
--- a/sysdeps/unix/sysv/linux/tst-setgetname.c
+++ b/sysdeps/unix/sysv/linux/tst-setgetname.c
@@ -43,12 +43,6 @@
    terminator.  */
 #define TASK_COMM_LEN 16
 
-long
-gettid (void)
-{
-    return syscall(__NR_gettid);
-}
-
 /* On Linux we can read this task's name from /proc.  */
 int
 get_self_comm (long tid, char *buf, size_t len)
diff --git a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
index 3b175f104b..ae93b8719b 100644
--- a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
@@ -1895,6 +1895,7 @@ GLIBC_2.28 thrd_current F
 GLIBC_2.28 thrd_equal F
 GLIBC_2.28 thrd_sleep F
 GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.3 __ctype_b_loc F
 GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
index 1b57710477..02110bac19 100644
--- a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
@@ -2146,4 +2146,5 @@ GLIBC_2.28 thrd_current F
 GLIBC_2.28 thrd_equal F
 GLIBC_2.28 thrd_sleep F
 GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
