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[PATCH v2] Add x86 32 bit vDSO time function support
- From: Adhemerval Zanella <azanella at linux dot vnet dot ibm dot com>
- To: "GNU C. Library" <libc-alpha at sourceware dot org>
- Cc: Stefani Seibold <stefani at seibold dot net>
- Date: Fri, 27 Jun 2014 18:21:01 -0300
- Subject: [PATCH v2] Add x86 32 bit vDSO time function support
- Authentication-results: sourceware.org; auth=none
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"