This is the mail archive of the libc-alpha@sourceware.org mailing list for the glibc project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

[PATCH v2] Add x86 32 bit vDSO time function support


Linux 3.15 adds support for clock_gettime, gettimeofday, and time vDSO
(commit id 37c975545ec63320789962bf307f000f08fabd48).  This patch adds
GLIBC supports to use such symbol when they are available.

Along with x86 vDSO support, this patch cleanup x86_64 code by moving
all common code to x86 common folder.  Only init-first.c is different
between implementations, since they differ substantially (x86_64 has
getcpu symbol where x86 does not).

This is a respin of https://sourceware.org/ml/libc-alpha/2014-04/msg00384.html

Checked on x86 and x86_64 with a 3.16-rc2 kernel.

--

2014-06-27  Adhemerval Zanella  <azanella@linux.vnet.ibm.com>
	    Stefani Seibold  <stefani@seibold.net>

	* sysdeps/unix/sysv/linux/i386/Makefile [sysdep_routines]: Add dl-vdso
	object.
	* sysdeps/unix/sysv/linux/i386/gettimeofday.c: New file: add support
	to vDSO.
	* sysdeps/unix/sysv/linux/i386/init-first.c: New file: likewise.
	* sysdeps/unix/sysv/linux/i386/time.c: New file: likewise.
	* sysdeps/unix/sysv/linux/x86_64/bits/libc-vdso.h: Moved to ...
	* sysdeps/unix/sysv/linux/x86/bits/libc-vdso.h: ... here.
	* sysdeps/unix/sysv/linux/x86_64/clock_gettime.c: Move to ...
	* sysdeps/unix/sysv/linux/x86/clock_gettime.c: ... here.
	* sysdeps/unix/sysv/linux/x86_64/gettimeofday.c: Move to ...
	* sysdeps/unix/sysv/linux/x86/gettimeofday.c: ... here. Also added
	fallback configurable symbol when vDSO is not available.
	* sysdeps/unix/sysv/linux/x86_64/time.c: Move to ...
	* sysdeps/unix/sysv/linux/x86/time.c: ... here. Also refactored to
	be able to redefine fallback symbol when vDSO is not available.
	* sysdeps/unix/sysv/linux/x86_64/timespec_get.c: Move to ...
	* sysdeps/unix/sysv/linux/x86/timespec_get.c: ... here.

---

diff --git a/sysdeps/unix/sysv/linux/i386/Makefile b/sysdeps/unix/sysv/linux/i386/Makefile
index acc3021..3222f46 100644
--- a/sysdeps/unix/sysv/linux/i386/Makefile
+++ b/sysdeps/unix/sysv/linux/i386/Makefile
@@ -21,3 +21,7 @@ endif
 ifeq ($(subdir),stdlib)
 gen-as-const-headers += ucontext_i.sym
 endif
+
+ifeq ($(subdir),elf)
+sysdep_routines += dl-vdso
+endif
diff --git a/sysdeps/unix/sysv/linux/i386/gettimeofday.c b/sysdeps/unix/sysv/linux/i386/gettimeofday.c
new file mode 100644
index 0000000..c45438c
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/i386/gettimeofday.c
@@ -0,0 +1,34 @@
+/* Copyright (C) 2014 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 <sys/time.h>
+
+#ifdef SHARED
+
+# include <dl-vdso.h>
+# include <errno.h>
+
+/* If the vDSO is not available we fall back on the syscall.  */
+static int
+__gettimeofday_syscall (struct timeval *tv, struct timezone *tz)
+{
+  return INLINE_SYSCALL (gettimeofday, 2, tv, tz);
+}
+# define GETTIMEOFAY_FALLBACK __gettimeofday_syscall
+#endif
+
+#include <sysdeps/unix/sysv/linux/x86/gettimeofday.c>
diff --git a/sysdeps/unix/sysv/linux/i386/init-first.c b/sysdeps/unix/sysv/linux/i386/init-first.c
new file mode 100644
index 0000000..10b0a97
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/i386/init-first.c
@@ -0,0 +1,53 @@
+/* Initialization code run first thing by the ELF startup code.  Linux/i386.
+   Copyright (C) 2014 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/>.  */
+
+#ifdef SHARED
+# include <time.h>
+# include <sysdep.h>
+# include <dl-vdso.h>
+# include <bits/libc-vdso.h>
+
+long int (*__vdso_clock_gettime) (clockid_t, struct timespec *)
+  __attribute__ ((nocommon));
+strong_alias (__vdso_clock_gettime, __GI___vdso_clock_gettime attribute_hidden)
+
+
+static long int
+clock_gettime_syscall (clockid_t id, struct timespec *tp)
+{
+  INTERNAL_SYSCALL_DECL (err);
+  return INTERNAL_SYSCALL (clock_gettime, err, 2, id, tp);
+}
+
+
+static inline void
+_libc_vdso_platform_setup (void)
+{
+  PREPARE_VERSION (linux26, "LINUX_2.6", 61765110);
+
+  void *p = _dl_vdso_vsym ("__vdso_clock_gettime", &linux26);
+  if (p == NULL)
+    p = clock_gettime_syscall;
+  PTR_MANGLE (p);
+  __GI___vdso_clock_gettime = p;
+}
+
+# define VDSO_SETUP _libc_vdso_platform_setup
+#endif
+
+#include <csu/init-first.c>
diff --git a/sysdeps/unix/sysv/linux/i386/time.c b/sysdeps/unix/sysv/linux/i386/time.c
new file mode 100644
index 0000000..616ec77
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/i386/time.c
@@ -0,0 +1,33 @@
+/* Copyright (C) 2014 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/>.  */
+
+#ifdef SHARED
+
+# include <dl-vdso.h>
+# include <errno.h>
+
+/* If the vDSO is not available we fall back on the old vsyscall.  */
+static time_t
+__time_syscall (time_t *t)
+{
+  INTERNAL_SYSCALL_DECL (err);
+  return INTERNAL_SYSCALL (time, err, 1, t);
+}
+# define TIME_FALLBACK  (void*)__time_syscall
+#endif
+
+#include <sysdeps/unix/sysv/linux/x86/time.c>
diff --git a/sysdeps/unix/sysv/linux/x86/bits/libc-vdso.h b/sysdeps/unix/sysv/linux/x86/bits/libc-vdso.h
new file mode 100644
index 0000000..f291924
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86/bits/libc-vdso.h
@@ -0,0 +1,31 @@
+/* Resolve function pointers to VDSO functions.
+   Copyright (C) 2005-2014 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 _LIBC_VDSO_H
+#define _LIBC_VDSO_H
+
+#include <time.h>
+#include <sys/time.h>
+
+#ifdef SHARED
+
+extern long int (*__vdso_clock_gettime) (clockid_t, struct timespec *);
+
+#endif
+
+#endif /* _LIBC_VDSO_H */
diff --git a/sysdeps/unix/sysv/linux/x86/clock_gettime.c b/sysdeps/unix/sysv/linux/x86/clock_gettime.c
new file mode 100644
index 0000000..f712110
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86/clock_gettime.c
@@ -0,0 +1,20 @@
+#include "bits/libc-vdso.h"
+
+#ifdef SHARED
+# define SYSCALL_GETTIME(id, tp) \
+  ({ long int (*f) (clockid_t, struct timespec *) = __vdso_clock_gettime; \
+  long int v_ret;							  \
+  PTR_DEMANGLE (f);							  \
+  v_ret = f (id, tp);							  \
+  if (INTERNAL_SYSCALL_ERROR_P (v_ret, )) {				  \
+    __set_errno (INTERNAL_SYSCALL_ERRNO (v_ret, ));			  \
+    v_ret = -1;								  \
+  }									  \
+  v_ret; })
+# define INTERNAL_GETTIME(id, tp) \
+  ({ long int (*f) (clockid_t, struct timespec *) = __vdso_clock_gettime; \
+  PTR_DEMANGLE (f);							  \
+  f (id, tp); })
+#endif
+
+#include "../clock_gettime.c"
diff --git a/sysdeps/unix/sysv/linux/x86/gettimeofday.c b/sysdeps/unix/sysv/linux/x86/gettimeofday.c
new file mode 100644
index 0000000..71f48bb
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86/gettimeofday.c
@@ -0,0 +1,57 @@
+/* Copyright (C) 2014 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 <sys/time.h>
+
+#ifdef SHARED
+
+# include <dl-vdso.h>
+
+void *gettimeofday_ifunc (void) __asm__ ("__gettimeofday");
+
+void *
+gettimeofday_ifunc (void)
+{
+  PREPARE_VERSION (linux26, "LINUX_2.6", 61765110);
+
+  /* If the vDSO is not available we fall back on the old vsyscall.  */
+  return (_dl_vdso_vsym ("__vdso_gettimeofday", &linux26)
+	  ?: (void *) GETTIMEOFAY_FALLBACK);
+}
+asm (".type __gettimeofday, %gnu_indirect_function");
+
+/* This is doing "libc_hidden_def (__gettimeofday)" but the compiler won't
+   let us do it in C because it doesn't know we're defining __gettimeofday
+   here in this file.  */
+asm (".globl __GI___gettimeofday\n"
+     "__GI___gettimeofday = __gettimeofday");
+
+#else
+
+# include <sysdep.h>
+# include <errno.h>
+
+int
+__gettimeofday (struct timeval *tv, struct timezone *tz)
+{
+  return INLINE_SYSCALL (gettimeofday, 2, tv, tz);
+}
+libc_hidden_def (__gettimeofday)
+
+#endif
+weak_alias (__gettimeofday, gettimeofday)
+libc_hidden_weak (gettimeofday)
diff --git a/sysdeps/unix/sysv/linux/x86/time.c b/sysdeps/unix/sysv/linux/x86/time.c
new file mode 100644
index 0000000..183754b
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86/time.c
@@ -0,0 +1,52 @@
+/* Copyright (C) 2014 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 <time.h>
+
+#ifdef SHARED
+
+#include <dl-vdso.h>
+
+void *time_ifunc (void) __asm__ ("time");
+
+void *
+time_ifunc (void)
+{
+  PREPARE_VERSION (linux26, "LINUX_2.6", 61765110);
+
+  return _dl_vdso_vsym ("__vdso_time", &linux26) ?: TIME_FALLBACK;
+}
+asm (".type time, %gnu_indirect_function");
+
+/* This is doing "libc_hidden_def (time)" but the compiler won't let us do
+   it in C because it doesn't know we're defining __gettimeofday here in
+    this file.  */
+asm (".globl __GI_time\n"
+     "__GI_time = time");
+
+#else
+
+# include <sysdep.h>
+
+time_t
+time (time_t *t)
+{
+  INTERNAL_SYSCALL_DECL (err);
+  return INTERNAL_SYSCALL (time, err, 1, t);
+}
+
+#endif
diff --git a/sysdeps/unix/sysv/linux/x86/timespec_get.c b/sysdeps/unix/sysv/linux/x86/timespec_get.c
new file mode 100644
index 0000000..cb26068
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86/timespec_get.c
@@ -0,0 +1,10 @@
+#include "bits/libc-vdso.h"
+
+#ifdef SHARED
+# define INTERNAL_GETTIME(id, tp) \
+  ({ long int (*f) (clockid_t, struct timespec *) = __vdso_clock_gettime; \
+  PTR_DEMANGLE (f);							  \
+  f (id, tp); })
+#endif
+
+#include "../timespec_get.c"
diff --git a/sysdeps/unix/sysv/linux/x86_64/bits/libc-vdso.h b/sysdeps/unix/sysv/linux/x86_64/bits/libc-vdso.h
deleted file mode 100644
index f291924..0000000
--- a/sysdeps/unix/sysv/linux/x86_64/bits/libc-vdso.h
+++ /dev/null
@@ -1,31 +0,0 @@
-/* Resolve function pointers to VDSO functions.
-   Copyright (C) 2005-2014 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 _LIBC_VDSO_H
-#define _LIBC_VDSO_H
-
-#include <time.h>
-#include <sys/time.h>
-
-#ifdef SHARED
-
-extern long int (*__vdso_clock_gettime) (clockid_t, struct timespec *);
-
-#endif
-
-#endif /* _LIBC_VDSO_H */
diff --git a/sysdeps/unix/sysv/linux/x86_64/clock_gettime.c b/sysdeps/unix/sysv/linux/x86_64/clock_gettime.c
deleted file mode 100644
index f712110..0000000
--- a/sysdeps/unix/sysv/linux/x86_64/clock_gettime.c
+++ /dev/null
@@ -1,20 +0,0 @@
-#include "bits/libc-vdso.h"
-
-#ifdef SHARED
-# define SYSCALL_GETTIME(id, tp) \
-  ({ long int (*f) (clockid_t, struct timespec *) = __vdso_clock_gettime; \
-  long int v_ret;							  \
-  PTR_DEMANGLE (f);							  \
-  v_ret = f (id, tp);							  \
-  if (INTERNAL_SYSCALL_ERROR_P (v_ret, )) {				  \
-    __set_errno (INTERNAL_SYSCALL_ERRNO (v_ret, ));			  \
-    v_ret = -1;								  \
-  }									  \
-  v_ret; })
-# define INTERNAL_GETTIME(id, tp) \
-  ({ long int (*f) (clockid_t, struct timespec *) = __vdso_clock_gettime; \
-  PTR_DEMANGLE (f);							  \
-  f (id, tp); })
-#endif
-
-#include "../clock_gettime.c"
diff --git a/sysdeps/unix/sysv/linux/x86_64/gettimeofday.c b/sysdeps/unix/sysv/linux/x86_64/gettimeofday.c
index 440ca7f..b0fa0e4 100644
--- a/sysdeps/unix/sysv/linux/x86_64/gettimeofday.c
+++ b/sysdeps/unix/sysv/linux/x86_64/gettimeofday.c
@@ -18,42 +18,9 @@
 #include <sys/time.h>
 
 #ifdef SHARED
-
-# include <dl-vdso.h>
-
+/* If the vDSO is not available we fall back on the old vsyscall.  */
 # define VSYSCALL_ADDR_vgettimeofday	0xffffffffff600000ul
-
-void *gettimeofday_ifunc (void) __asm__ ("__gettimeofday");
-
-void *
-gettimeofday_ifunc (void)
-{
-  PREPARE_VERSION (linux26, "LINUX_2.6", 61765110);
-
-  /* If the vDSO is not available we fall back on the old vsyscall.  */
-  return (_dl_vdso_vsym ("__vdso_gettimeofday", &linux26)
-	  ?: (void *) VSYSCALL_ADDR_vgettimeofday);
-}
-asm (".type __gettimeofday, %gnu_indirect_function");
-
-/* This is doing "libc_hidden_def (__gettimeofday)" but the compiler won't
-   let us do it in C because it doesn't know we're defining __gettimeofday
-   here in this file.  */
-asm (".globl __GI___gettimeofday\n"
-     "__GI___gettimeofday = __gettimeofday");
-
-#else
-
-# include <sysdep.h>
-# include <errno.h>
-
-int
-__gettimeofday (struct timeval *tv, struct timezone *tz)
-{
-  return INLINE_SYSCALL (gettimeofday, 2, tv, tz);
-}
-libc_hidden_def (__gettimeofday)
-
+# define GETTIMEOFAY_FALLBACK VSYSCALL_ADDR_vgettimeofday
 #endif
-weak_alias (__gettimeofday, gettimeofday)
-libc_hidden_weak (gettimeofday)
+
+#include <sysdeps/unix/sysv/linux/x86/gettimeofday.c>
diff --git a/sysdeps/unix/sysv/linux/x86_64/time.c b/sysdeps/unix/sysv/linux/x86_64/time.c
index 79f1fab..ec1393b 100644
--- a/sysdeps/unix/sysv/linux/x86_64/time.c
+++ b/sysdeps/unix/sysv/linux/x86_64/time.c
@@ -16,45 +16,9 @@
    <http://www.gnu.org/licenses/>.  */
 
 #ifdef SHARED
-/* Redefine time so that the compiler won't complain about the type
-   mismatch with the IFUNC selector in strong_alias, below.  */
-#undef time
-#define time __redirect_time
-#include <time.h>
-
-#include <dl-vdso.h>
-
+/* If the vDSO is not available we fall back on the old vsyscall.  */
 #define VSYSCALL_ADDR_vtime	0xffffffffff600400
-
-/* Avoid DWARF definition DIE on ifunc symbol so that GDB can handle
-   ifunc symbol properly.  */
-extern __typeof (__redirect_time) __libc_time;
-void *time_ifunc (void) __asm__ ("__libc_time");
-
-void *
-time_ifunc (void)
-{
-  PREPARE_VERSION (linux26, "LINUX_2.6", 61765110);
-
-  /* If the vDSO is not available we fall back on the old vsyscall.  */
-  return _dl_vdso_vsym ("__vdso_time", &linux26) ?: (void *) VSYSCALL_ADDR_vtime;
-}
-__asm (".type __libc_time, %gnu_indirect_function");
-
-#undef time
-strong_alias (__libc_time, time)
-libc_hidden_ver (__libc_time, time)
-
-#else
-
-# include <time.h>
-# include <sysdep.h>
-
-time_t
-time (time_t *t)
-{
-  INTERNAL_SYSCALL_DECL (err);
-  return INTERNAL_SYSCALL (time, err, 1, t);
-}
-
+#define TIME_FALLBACK           (void*)VSYSCALL_ADDR_vtime
 #endif
+
+#include <sysdeps/unix/sysv/linux/x86/time.c>
diff --git a/sysdeps/unix/sysv/linux/x86_64/timespec_get.c b/sysdeps/unix/sysv/linux/x86_64/timespec_get.c
deleted file mode 100644
index cb26068..0000000
--- a/sysdeps/unix/sysv/linux/x86_64/timespec_get.c
+++ /dev/null
@@ -1,10 +0,0 @@
-#include "bits/libc-vdso.h"
-
-#ifdef SHARED
-# define INTERNAL_GETTIME(id, tp) \
-  ({ long int (*f) (clockid_t, struct timespec *) = __vdso_clock_gettime; \
-  PTR_DEMANGLE (f);							  \
-  f (id, tp); })
-#endif
-
-#include "../timespec_get.c"


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]