[PATCHv2] MIPS: Add VDSO support
diff mbox

Message ID 1460386073-14198-1-git-send-email-Zubair.Kakakhel@imgtec.com
State New
Headers show

Commit Message

Zubair Lutfullah Kakakhel April 11, 2016, 2:47 p.m. UTC
From: Alex Smith <alex.smith@imgtec.com>

This patch adds support for using the implementations of gettimeofday()
and clock_gettime() provided by the kernel in the VDSO. The VDSO will
always provide clock_gettime() as CLOCK_{REALTIME,MONOTONIC}_COARSE can
be implemented regardless of platform. CLOCK_{REALTIME,MONOTONIC}, along
with gettimeofday(), are only implemented on platforms which make use of
either the CP0 count or GIC as their clocksource. On other platforms,
the VDSO does not provide the __vdso_gettimeofday symbol, as it is
never useful.

The VDSO functions return ENOSYS when they encounter an unsupported
request, in which case glibc should fall back to the standard syscall.

	* sysdeps/unix/sysv/linux/mips/Makefile (sysdep_routines):
	Include dl-vdso.
	* sysdeps/unix/sysv/linux/mips/Versions: Add
	__vdso_clock_gettime.
	* sysdeps/unix/sysv/linux/mips/init-first.c: New file.
	* sysdeps/unix/sysv/linux/mips/libc-vdso.h: New file.
	* sysdeps/unix/sysv/linux/mips/mips32/sysdep.h:
	(INTERNAL_VSYSCALL_CALL): Define to be compatible with MIPS
	definitions of INTERNAL_SYSCALL_{ERROR_P,ERRNO}.
	(HAVE_CLOCK_GETTIME_VSYSCALL): Define.
	(HAVE_GETTIMEOFDAY_VSYSCALL): Define.
	* sysdeps/unix/sysv/linux/mips/mips64/n32/sysdep.h: Likewise.
	* sysdeps/unix/sysv/linux/mips/mips64/n64/sysdep.h: Likewise.

---
V1 -> V2

Update copyright notice year from 2015 to 2016.

V1
Hi,

The kernel patches for vdso support are already upstream.

I'm picking up this patch to upstream vdso support for MIPS in glibc.

Rebased this patch on glibc-2.23

Tested with upstream kernel 4.5 and QEMU emulating Malta.

 ./vdsotest gettimeofday bench
gettimeofday: syscall: 1021 nsec/call
gettimeofday:    libc: 262 nsec/call
gettimeofday:    vdso: 174 nsec/call

Regards,
ZubairLK
---
 sysdeps/unix/sysv/linux/mips/Makefile            |  2 ++
 sysdeps/unix/sysv/linux/mips/Versions            |  4 +++
 sysdeps/unix/sysv/linux/mips/init-first.c        | 44 ++++++++++++++++++++++++
 sysdeps/unix/sysv/linux/mips/libc-vdso.h         | 33 ++++++++++++++++++
 sysdeps/unix/sysv/linux/mips/mips32/sysdep.h     | 16 +++++++++
 sysdeps/unix/sysv/linux/mips/mips64/n32/sysdep.h | 17 +++++++++
 sysdeps/unix/sysv/linux/mips/mips64/n64/sysdep.h | 17 +++++++++
 7 files changed, 133 insertions(+)
 create mode 100644 sysdeps/unix/sysv/linux/mips/init-first.c
 create mode 100644 sysdeps/unix/sysv/linux/mips/libc-vdso.h

Comments

Matthew Fortune April 11, 2016, 2:53 p.m. UTC | #1
Zubair Kakakhel <Zubair.Kakakhel@imgtec.com> writes:
> From: Alex Smith <alex.smith@imgtec.com>
> ---
> V1 -> V2
> 
> Update copyright notice year from 2015 to 2016.

Do you have commit rights to glibc or do you need this
committing? Is the code written by Alex Smith and
yourself (for the changelog)?

Thanks,
Matthew
Zubair Lutfullah Kakakhel April 12, 2016, 7:15 a.m. UTC | #2
Hi,

On 11/04/16 15:53, Matthew Fortune wrote:
> Zubair Kakakhel <Zubair.Kakakhel@imgtec.com> writes:
>> From: Alex Smith <alex.smith@imgtec.com>
>> ---
>> V1 -> V2
>>
>> Update copyright notice year from 2015 to 2016.
>
> Do you have commit rights to glibc or do you need this
> committing? Is the code written by Alex Smith and
> yourself (for the changelog)?

I don't have commit rights to glibc.

I'd like this committing please.

The code is by Alex. I rebased, tested again on upstream and added the changelog.

Regards,
ZubairLK

>
> Thanks,
> Matthew
>
Matthew Fortune April 12, 2016, 10:08 a.m. UTC | #3
Zubair Kakakhel <Zubair.Kakakhel@imgtec.com> writes:
> I'd like this committing please.
> 
> The code is by Alex. I rebased, tested again on upstream and added the
> changelog.

Committed with Alex as author in the changelog.

Matthew
Joseph Myers April 21, 2016, 5:08 p.m. UTC | #4
On Tue, 12 Apr 2016, Matthew Fortune wrote:

> Zubair Kakakhel <Zubair.Kakakhel@imgtec.com> writes:
> > I'd like this committing please.
> > 
> > The code is by Alex. I rebased, tested again on upstream and added the
> > changelog.
> 
> Committed with Alex as author in the changelog.

For future reference, please use --author when committing a patch for 
someone else.
Maciej W. Rozycki April 21, 2016, 8:57 p.m. UTC | #5
On Thu, 21 Apr 2016, Joseph Myers wrote:

> > > I'd like this committing please.
> > > 
> > > The code is by Alex. I rebased, tested again on upstream and added the
> > > changelog.
> > 
> > Committed with Alex as author in the changelog.
> 
> For future reference, please use --author when committing a patch for 
> someone else.

 Or `git am' would have handled this correctly as well, automagically as 
the e-mail was correctly formatted (with a `From' tag on the first body 
line in particular) for importing directly into GIT.

  Maciej
Matthew Fortune April 21, 2016, 10:14 p.m. UTC | #6
Maciej Rozycki <Maciej.Rozycki@imgtec.com> writes:
> On Thu, 21 Apr 2016, Joseph Myers wrote:
> 
> > > > I'd like this committing please.
> > > >
> > > > The code is by Alex. I rebased, tested again on upstream and added the
> > > > changelog.
> > >
> > > Committed with Alex as author in the changelog.
> >
> > For future reference, please use --author when committing a patch for
> > someone else.
> 
>  Or `git am' would have handled this correctly as well, automagically as
> the e-mail was correctly formatted (with a `From' tag on the first body
> line in particular) for importing directly into GIT.

Yes, sorry about that. I'm not used to committing for someone else via
git. Will make sure it is in place next time.

Matthew

Patch
diff mbox

diff --git a/sysdeps/unix/sysv/linux/mips/Makefile b/sysdeps/unix/sysv/linux/mips/Makefile
index 8127025..c6729c1 100644
--- a/sysdeps/unix/sysv/linux/mips/Makefile
+++ b/sysdeps/unix/sysv/linux/mips/Makefile
@@ -96,6 +96,8 @@  ifeq ($(subdir),elf)
 ifeq ($(build-shared),yes)
 # This is needed for DSO loading from static binaries.
 sysdep-dl-routines += dl-static
+
+sysdep_routines += dl-vdso
 endif
 endif
 
diff --git a/sysdeps/unix/sysv/linux/mips/Versions b/sysdeps/unix/sysv/linux/mips/Versions
index a56322a..453f276 100644
--- a/sysdeps/unix/sysv/linux/mips/Versions
+++ b/sysdeps/unix/sysv/linux/mips/Versions
@@ -37,4 +37,8 @@  libc {
   GLIBC_2.11 {
     fallocate64;
   }
+  GLIBC_PRIVATE {
+    # nptl/pthread_cond_timedwait.c uses INTERNAL_VSYSCALL(clock_gettime).
+    __vdso_clock_gettime;
+  }
 }
diff --git a/sysdeps/unix/sysv/linux/mips/init-first.c b/sysdeps/unix/sysv/linux/mips/init-first.c
new file mode 100644
index 0000000..1b50f16
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/mips/init-first.c
@@ -0,0 +1,44 @@ 
+/* Initialization code run first thing by the ELF startup code.
+   Copyright (C) 2016 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 <libc-vdso.h>
+
+int (*VDSO_SYMBOL(gettimeofday)) (struct timeval *, void *) attribute_hidden;
+int (*VDSO_SYMBOL(clock_gettime)) (clockid_t, struct timespec *);
+
+static inline void
+_libc_vdso_platform_setup (void)
+{
+  PREPARE_VERSION_KNOWN (linux26, LINUX_2_6);
+
+  void *p = _dl_vdso_vsym ("__vdso_gettimeofday", &linux26);
+  PTR_MANGLE (p);
+  VDSO_SYMBOL (gettimeofday) = p;
+
+  p = _dl_vdso_vsym ("__vdso_clock_gettime", &linux26);
+  PTR_MANGLE (p);
+  VDSO_SYMBOL (clock_gettime) = p;
+}
+
+# define VDSO_SETUP _libc_vdso_platform_setup
+#endif
+
+#include <csu/init-first.c>
diff --git a/sysdeps/unix/sysv/linux/mips/libc-vdso.h b/sysdeps/unix/sysv/linux/mips/libc-vdso.h
new file mode 100644
index 0000000..66e5da6
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/mips/libc-vdso.h
@@ -0,0 +1,33 @@ 
+/* VDSO function pointer declarations.
+   Copyright (C) 2016 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
+
+#ifdef SHARED
+
+# include <sysdep-vdso.h>
+
+extern int (*VDSO_SYMBOL(gettimeofday)) (struct timeval *, void *)
+   attribute_hidden;
+extern int (*VDSO_SYMBOL(clock_gettime)) (clockid_t, struct timespec *);
+
+#endif
+
+#endif /* _LIBC_VDSO_H */
diff --git a/sysdeps/unix/sysv/linux/mips/mips32/sysdep.h b/sysdeps/unix/sysv/linux/mips/mips32/sysdep.h
index 2160df7..2335409 100644
--- a/sysdeps/unix/sysv/linux/mips/mips32/sysdep.h
+++ b/sysdeps/unix/sysv/linux/mips/mips32/sysdep.h
@@ -371,6 +371,22 @@ 
 #define __SYSCALL_CLOBBERS "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13", \
 	"$14", "$15", "$24", "$25", "hi", "lo", "memory"
 
+/* Standard MIPS syscalls have an error flag, and return a positive errno
+   when the error flag is set. Emulate this behaviour for vsyscalls so that
+   the INTERNAL_SYSCALL_{ERROR_P,ERRNO} macros work correctly.  */
+#define INTERNAL_VSYSCALL_CALL(funcptr, err, nr, args...)		\
+  ({									\
+    long _ret = funcptr (args);						\
+    err = ((unsigned long) (_ret) >= (unsigned long) -4095L);		\
+    if (err)								\
+      _ret = -_ret;							\
+    _ret;								\
+  })
+
+/* List of system calls which are supported as vsyscalls.  */
+#define HAVE_CLOCK_GETTIME_VSYSCALL	1
+#define HAVE_GETTIMEOFDAY_VSYSCALL	1
+
 #endif /* __ASSEMBLER__ */
 
 /* Pointer mangling is not yet supported for MIPS.  */
diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n32/sysdep.h b/sysdeps/unix/sysv/linux/mips/mips64/n32/sysdep.h
index 466dcde..661b3dc 100644
--- a/sysdeps/unix/sysv/linux/mips/mips64/n32/sysdep.h
+++ b/sysdeps/unix/sysv/linux/mips/mips64/n32/sysdep.h
@@ -295,6 +295,23 @@ 
 
 #define __SYSCALL_CLOBBERS "$1", "$3", "$10", "$11", "$12", "$13", \
 	"$14", "$15", "$24", "$25", "hi", "lo", "memory"
+
+/* Standard MIPS syscalls have an error flag, and return a positive errno
+   when the error flag is set. Emulate this behaviour for vsyscalls so that
+   the INTERNAL_SYSCALL_{ERROR_P,ERRNO} macros work correctly.  */
+#define INTERNAL_VSYSCALL_CALL(funcptr, err, nr, args...)		\
+  ({									\
+    long _ret = funcptr (args);						\
+    err = ((unsigned long) (_ret) >= (unsigned long) -4095L);		\
+    if (err)								\
+      _ret = -_ret;							\
+    _ret;								\
+  })
+
+/* List of system calls which are supported as vsyscalls.  */
+#define HAVE_CLOCK_GETTIME_VSYSCALL	1
+#define HAVE_GETTIMEOFDAY_VSYSCALL	1
+
 #endif /* __ASSEMBLER__ */
 
 /* Pointer mangling is not yet supported for MIPS.  */
diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n64/sysdep.h b/sysdeps/unix/sysv/linux/mips/mips64/n64/sysdep.h
index db8b237..476eca3 100644
--- a/sysdeps/unix/sysv/linux/mips/mips64/n64/sysdep.h
+++ b/sysdeps/unix/sysv/linux/mips/mips64/n64/sysdep.h
@@ -291,6 +291,23 @@ 
 
 #define __SYSCALL_CLOBBERS "$1", "$3", "$10", "$11", "$12", "$13", \
 	"$14", "$15", "$24", "$25", "hi", "lo", "memory"
+
+/* Standard MIPS syscalls have an error flag, and return a positive errno
+   when the error flag is set. Emulate this behaviour for vsyscalls so that
+   the INTERNAL_SYSCALL_{ERROR_P,ERRNO} macros work correctly.  */
+#define INTERNAL_VSYSCALL_CALL(funcptr, err, nr, args...)		\
+  ({									\
+    long _ret = funcptr (args);						\
+    err = ((unsigned long) (_ret) >= (unsigned long) -4095L);		\
+    if (err)								\
+      _ret = -_ret;							\
+    _ret;								\
+  })
+
+/* List of system calls which are supported as vsyscalls.  */
+#define HAVE_CLOCK_GETTIME_VSYSCALL	1
+#define HAVE_GETTIMEOFDAY_VSYSCALL	1
+
 #endif /* __ASSEMBLER__ */
 
 /* Pointer mangling is not yet supported for MIPS.  */