Implement the mlock2 function

Fallback using mlock is provided if the flags argument is zero.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>

37 files changed, 194 insertions, 5 deletions

diff --git a/ChangeLog b/ChangeLog
index 389e39ea39..b7779c6b59 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,16 @@
+2017-11-27  Florian Weimer  <fweimer@redhat.com>
+
+	* sysdeps/unix/sysv/linux/mlock2.c: New file.
+	* sysdeps/unix/sysv/linux/tst-mlock2.c: Likewise.
+	* sysdeps/unix/sysv/linux/Makefile (routines): Add mlock2.
+	(tests): Add tst-mlock2.
+	* sysdeps/unix/sysv/linux/Versions (GLIBC_2.27): Export mlock2.
+	* sysdeps/unix/sysv/linux/kernel-features.h (__ASSUME_MLOCK2)
+	[__LINUX_KERNEL_VERSION >= 4.4]: Define.
+	* sysdeps/unix/sysv/linux/libc**.abilist: Update.
+	* manual/memory.texi (Page Lock Functions): Move @end deftypefun
+	for mlock.  Document mlock2.
+
 2017-11-27  Joseph Myers  <joseph@codesourcery.com>
 
 	* sysdeps/ia64/Makeconfig (float64x-alias-fcts): New variable.
diff --git a/NEWS b/NEWS
index 33c62abf2f..f3fdf9aec5 100644
--- a/NEWS
+++ b/NEWS
@@ -41,7 +41,7 @@ Major new features:
   18661-3:2015.  These are corresponding interfaces to those supported for
   _Float128.
 
-* glibc now implements the memfd_create function on Linux.
+* glibc now implements the memfd_create and mlock2 functions on Linux.
 
 Deprecated and removed features, and other changes affecting compatibility:
 
diff --git a/manual/memory.texi b/manual/memory.texi
index 3f5dd90260..1b431bf5da 100644
--- a/manual/memory.texi
+++ b/manual/memory.texi
@@ -3337,6 +3337,36 @@ The calling process is not superuser.
 The kernel does not provide @code{mlock} capability.
 
 @end table
+@end deftypefun
+
+@deftypefun int mlock2 (const void *@var{addr}, size_t @var{len}, unsigned int @var{flags})
+@standards{Linux, sys/mman.h}
+@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}}
+
+This function is similar to @code{mlock}.  If @var{flags} is zero, a
+call to @code{mlock2} behaves exactly as the equivalent call to @code{mlock}.
+
+The @var{flags} argument must be a combination of zero or more of the
+following flags:
+
+@vtable @code
+@item MLOCK_ONFAULT
+@standards{Linux, sys/mman.h}
+Only those pages in the specified address range which are already in
+memory are locked immediately.  Additional pages in the range are
+automatically locked in case of a page fault and allocation of memory.
+@end vtable
+
+Like @code{mlock}, @code{mlock2} returns zero on success and @code{-1}
+on failure, setting @code{errno} accordingly.  Additional @code{errno}
+values defined for @code{mlock2} are:
+
+@table @code
+@item EINVAL
+The specified (non-zero) @var{flags} argument is not supported by this
+system.
+@end table
+@end deftypefun
 
 You can lock @emph{all} a process' memory with @code{mlockall}.  You
 unlock memory with @code{munlock} or @code{munlockall}.
@@ -3346,8 +3376,6 @@ To avoid all page faults in a C program, you have to use
 from the C code, e.g. the stack and automatic variables, and you
 wouldn't know what address to tell @code{mlock}.
 
-@end deftypefun
-
 @deftypefun int munlock (const void *@var{addr}, size_t @var{len})
 @standards{POSIX.1b, sys/mman.h}
 @safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}}
diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
index 58ce07b526..478f7e3d4d 100644
--- a/sysdeps/unix/sysv/linux/Makefile
+++ b/sysdeps/unix/sysv/linux/Makefile
@@ -18,7 +18,7 @@ sysdep_routines += clone umount umount2 readahead \
 		   setfsuid setfsgid epoll_pwait signalfd \
 		   eventfd eventfd_read eventfd_write prlimit \
 		   personality epoll_wait tee vmsplice splice \
-		   open_by_handle_at
+		   open_by_handle_at mlock2
 
 CFLAGS-gethostid.c = -fexceptions
 CFLAGS-tee.c = -fexceptions -fasynchronous-unwind-tables
@@ -44,7 +44,7 @@ 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
+	 test-errno-linux tst-memfd_create tst-mlock2
 
 # Generate the list of SYS_* macros for the system calls (__NR_*
 # macros).  The file syscall-names.list contains all possible system
diff --git a/sysdeps/unix/sysv/linux/Versions b/sysdeps/unix/sysv/linux/Versions
index 6f2fe516d7..e799b62285 100644
--- a/sysdeps/unix/sysv/linux/Versions
+++ b/sysdeps/unix/sysv/linux/Versions
@@ -168,6 +168,7 @@ libc {
   }
   GLIBC_2.27 {
     memfd_create;
+    mlock2;
   }
   GLIBC_PRIVATE {
     # functions used in other libraries
diff --git a/sysdeps/unix/sysv/linux/aarch64/libc.abilist b/sysdeps/unix/sysv/linux/aarch64/libc.abilist
index af60b4f577..3448d62cee 100644
--- a/sysdeps/unix/sysv/linux/aarch64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/aarch64/libc.abilist
@@ -2107,6 +2107,7 @@ GLIBC_2.27 GLIBC_2.27 A
 GLIBC_2.27 glob F
 GLIBC_2.27 glob64 F
 GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
 GLIBC_2.27 strfromf128 F
 GLIBC_2.27 strfromf64x F
 GLIBC_2.27 strtof128 F
diff --git a/sysdeps/unix/sysv/linux/alpha/libc.abilist b/sysdeps/unix/sysv/linux/alpha/libc.abilist
index 98c6a17ae1..d064f5445e 100644
--- a/sysdeps/unix/sysv/linux/alpha/libc.abilist
+++ b/sysdeps/unix/sysv/linux/alpha/libc.abilist
@@ -2018,6 +2018,7 @@ GLIBC_2.27 GLIBC_2.27 A
 GLIBC_2.27 glob F
 GLIBC_2.27 glob64 F
 GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
 GLIBC_2.27 strfromf128 F
 GLIBC_2.27 strfromf64x F
 GLIBC_2.27 strtof128 F
diff --git a/sysdeps/unix/sysv/linux/arm/libc.abilist b/sysdeps/unix/sysv/linux/arm/libc.abilist
index 8a8af3e3e4..a5ce7964d0 100644
--- a/sysdeps/unix/sysv/linux/arm/libc.abilist
+++ b/sysdeps/unix/sysv/linux/arm/libc.abilist
@@ -108,6 +108,7 @@ GLIBC_2.27 GLIBC_2.27 A
 GLIBC_2.27 glob F
 GLIBC_2.27 glob64 F
 GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
 GLIBC_2.4 GLIBC_2.4 A
 GLIBC_2.4 _Exit F
 GLIBC_2.4 _IO_2_1_stderr_ D 0xa0
diff --git a/sysdeps/unix/sysv/linux/bits/mman-shared.h b/sysdeps/unix/sysv/linux/bits/mman-shared.h
index 5bbcbbc14a..bee99c2384 100644
--- a/sysdeps/unix/sysv/linux/bits/mman-shared.h
+++ b/sysdeps/unix/sysv/linux/bits/mman-shared.h
@@ -28,12 +28,21 @@
 #  define MFD_HUGETLB 4U
 # endif
 
+/* Flags for mlock2.  */
+# ifndef MLOCK_ONFAULT
+#  define MLOCK_ONFAULT 1U
+# endif
+
 __BEGIN_DECLS
 
 /* Create a new memory file descriptor.  NAME is a name for debugging.
    FLAGS is a combination of the MFD_* constants.  */
 int memfd_create (const char *__name, unsigned int __flags) __THROW;
 
+/* Lock pages from ADDR (inclusive) to ADDR + LENGTH (exclusive) into
+   memory.  FLAGS is a combination of the MLOCK_* flags above.  */
+int mlock2 (const void *__addr, size_t __length, unsigned int __flags) __THROW;
+
 __END_DECLS
 
 #endif /* __USE_GNU */
diff --git a/sysdeps/unix/sysv/linux/hppa/libc.abilist b/sysdeps/unix/sysv/linux/hppa/libc.abilist
index 5b81a6cd7d..69ddf15361 100644
--- a/sysdeps/unix/sysv/linux/hppa/libc.abilist
+++ b/sysdeps/unix/sysv/linux/hppa/libc.abilist
@@ -1872,6 +1872,7 @@ GLIBC_2.27 GLIBC_2.27 A
 GLIBC_2.27 glob F
 GLIBC_2.27 glob64 F
 GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
 GLIBC_2.3 GLIBC_2.3 A
 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 1526778ec2..a140edd4a3 100644
--- a/sysdeps/unix/sysv/linux/i386/libc.abilist
+++ b/sysdeps/unix/sysv/linux/i386/libc.abilist
@@ -2037,6 +2037,7 @@ GLIBC_2.27 GLIBC_2.27 A
 GLIBC_2.27 glob F
 GLIBC_2.27 glob64 F
 GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
 GLIBC_2.27 strfromf64x F
 GLIBC_2.27 strtof64x F
 GLIBC_2.27 strtof64x_l F
diff --git a/sysdeps/unix/sysv/linux/ia64/libc.abilist b/sysdeps/unix/sysv/linux/ia64/libc.abilist
index 132200f2bd..178c0a45ec 100644
--- a/sysdeps/unix/sysv/linux/ia64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/ia64/libc.abilist
@@ -1901,6 +1901,7 @@ GLIBC_2.27 GLIBC_2.27 A
 GLIBC_2.27 glob F
 GLIBC_2.27 glob64 F
 GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
 GLIBC_2.27 strfromf64x F
 GLIBC_2.27 strtof64x F
 GLIBC_2.27 strtof64x_l F
diff --git a/sysdeps/unix/sysv/linux/kernel-features.h b/sysdeps/unix/sysv/linux/kernel-features.h
index 2e1fe6597a..59b613377f 100644
--- a/sysdeps/unix/sysv/linux/kernel-features.h
+++ b/sysdeps/unix/sysv/linux/kernel-features.h
@@ -107,3 +107,7 @@
 #if __LINUX_KERNEL_VERSION >= 0x031300
 # define __ASSUME_EXECVEAT	1
 #endif
+
+#if __LINUX_KERNEL_VERSION >= 0x040400
+# define __ASSUME_MLOCK2 1
+#endif
diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
index d9c97779e4..01d10d907c 100644
--- a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
+++ b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
@@ -109,6 +109,7 @@ GLIBC_2.27 GLIBC_2.27 A
 GLIBC_2.27 glob F
 GLIBC_2.27 glob64 F
 GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
 GLIBC_2.4 GLIBC_2.4 A
 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 4acbf7eeed..3ad08c20bf 100644
--- a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
+++ b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
@@ -1986,6 +1986,7 @@ GLIBC_2.27 GLIBC_2.27 A
 GLIBC_2.27 glob F
 GLIBC_2.27 glob64 F
 GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
 GLIBC_2.3 GLIBC_2.3 A
 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 93f02f08ce..6bd7be1929 100644
--- a/sysdeps/unix/sysv/linux/microblaze/libc.abilist
+++ b/sysdeps/unix/sysv/linux/microblaze/libc.abilist
@@ -2107,3 +2107,4 @@ GLIBC_2.27 GLIBC_2.27 A
 GLIBC_2.27 glob F
 GLIBC_2.27 glob64 F
 GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
diff --git a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
index 795e85de70..9b1e890eda 100644
--- a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
@@ -1961,6 +1961,7 @@ GLIBC_2.27 GLIBC_2.27 A
 GLIBC_2.27 glob F
 GLIBC_2.27 glob64 F
 GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
 GLIBC_2.3 GLIBC_2.3 A
 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 dc714057b7..3eb5b66f8b 100644
--- a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
@@ -1959,6 +1959,7 @@ GLIBC_2.27 GLIBC_2.27 A
 GLIBC_2.27 glob F
 GLIBC_2.27 glob64 F
 GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
 GLIBC_2.3 GLIBC_2.3 A
 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 6ec940ee99..543a725114 100644
--- a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
@@ -1957,6 +1957,7 @@ GLIBC_2.27 GLIBC_2.27 A
 GLIBC_2.27 glob F
 GLIBC_2.27 glob64 F
 GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
 GLIBC_2.27 strfromf128 F
 GLIBC_2.27 strfromf64x F
 GLIBC_2.27 strtof128 F
diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
index 71062b0eed..a9198a3936 100644
--- a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
@@ -1952,6 +1952,7 @@ GLIBC_2.27 GLIBC_2.27 A
 GLIBC_2.27 glob F
 GLIBC_2.27 glob64 F
 GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
 GLIBC_2.27 strfromf128 F
 GLIBC_2.27 strfromf64x F
 GLIBC_2.27 strtof128 F
diff --git a/sysdeps/unix/sysv/linux/mlock2.c b/sysdeps/unix/sysv/linux/mlock2.c
new file mode 100644
index 0000000000..1686ab9b85
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/mlock2.c
@@ -0,0 +1,40 @@
+/* Wrapper for the mlock2 system call with fallback to mlock.
+   Copyright (C) 2017 Free Software Foundation, Inc.
+
+   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.
+
+