Module: xenomai-gch
Branch: for-head
Commit: 76444be87d0e602a14a79b949eb841df15a3cff2
URL:    
http://git.xenomai.org/?p=xenomai-gch.git;a=commit;h=76444be87d0e602a14a79b949eb841df15a3cff2

Author: Wolfgang Mauerer <wolfgang.maue...@siemens.com>
Date:   Wed Dec 23 10:25:51 2009 +0100

nucleus: Add support for sharing data between Xenomai kernel and userland

A new structure (struct xnshared) is introduced. It allows us to share
generic data between user and kernel of Xenomai; a bitmap of feature
flags located at the beginning of the structure identifies which data
are shared. The structure is allocated in the global semaphore heap,
and xnsysinfo.xnshared_offset identifies the offset of the structure
within the heap.

Currently, no shared features are yet supported - the patch only
introduces the necessary ABI changes. When the need arises
to share data between said entities, the structure must
be accordingly extended, and a new feature bit must be added
to the flags.

Signed-off-by: Wolfgang Mauerer <wolfgang.maue...@siemens.com>
Signed-off-by: Jan Kiszka <jan.kis...@siemens.com>

---

 include/asm-generic/syscall.h |    1 +
 include/nucleus/Makefile.am   |    3 +-
 include/nucleus/xnvdso.h      |   61 +++++++++++++++++++++++++++++++++++++++++
 ksrc/nucleus/module.c         |    7 +++++
 ksrc/nucleus/shadow.c         |   22 +++++++++++++++
 5 files changed, 93 insertions(+), 1 deletions(-)

diff --git a/include/asm-generic/syscall.h b/include/asm-generic/syscall.h
index 483b99f..8f1ddc6 100644
--- a/include/asm-generic/syscall.h
+++ b/include/asm-generic/syscall.h
@@ -53,6 +53,7 @@
 typedef struct xnsysinfo {
        unsigned long long cpufreq;     /* CPU frequency */
        unsigned long tickval;          /* Tick duration (ns) */
+       unsigned long xnvdso_off;       /* Offset of xnvdso in the sem heap */
 } xnsysinfo_t;
 
 #define SIGSHADOW  SIGWINCH
diff --git a/include/nucleus/Makefile.am b/include/nucleus/Makefile.am
index 4be05f8..26d3fa2 100644
--- a/include/nucleus/Makefile.am
+++ b/include/nucleus/Makefile.am
@@ -34,4 +34,5 @@ includesub_HEADERS = \
        trace.h \
        types.h \
        version.h \
-       xenomai.h
+       xenomai.h \
+       xnvdso.h
diff --git a/include/nucleus/xnvdso.h b/include/nucleus/xnvdso.h
new file mode 100644
index 0000000..fbff8fa
--- /dev/null
+++ b/include/nucleus/xnvdso.h
@@ -0,0 +1,61 @@
+#ifndef _XENO_NUCLEUS_XNVDSO_H
+#define _XENO_NUCLEUS_XNVDSO_H
+
+/*!\file xnvdso.h
+ * \brief Definitions for global semaphore heap shared objects
+ * \author Wolfgang Mauerer
+ *
+ * Copyright (C) 2009 Wolfgang Mauerer <wolfgang.maue...@siemens.com>.
+ *
+ * Xenomai is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published
+ * by the Free Software Foundation; either version 2 of the License,
+ * or (at your option) any later version.
+ *
+ * Xenomai 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
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Xenomai; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ */
+
+#include <nucleus/types.h>
+
+/*
+ * Data shared between Xenomai kernel/userland and the Linux kernel/userland
+ * on the global semaphore heap. The features element indicates which data are
+ * shared. Notice that struct xnvdso may only grow, but never shrink.
+ */
+struct xnvdso {
+       unsigned long long features;
+
+       /* Embed domain specific structures that describe the
+        * shared data here */
+};
+
+/*
+ * For each shared feature, add a flag below. For now, the set is still
+ * empty.
+ */
+/*
+#define XNVDSO_FEAT_A  0x0000000000000001
+#define XNVDSO_FEAT_B  0x0000000000000002
+#define XNVDSO_FEAT_C  0x0000000000000004
+#define XNVDSO_FEATURES        (XNVDSO_FEAT_A | XNVDSO_FEAT_B | XVDSO_FEAT_C)
+*/
+
+#define XNVDSO_FEATURES 0x0000000000000000
+
+extern struct xnvdso *xnvdso;
+
+static inline int xnvdso_test_feature(unsigned long long feature)
+{
+       return testbits(xnvdso->features, feature);
+}
+
+extern void xnheap_init_vdso(void);
+#endif /* _XENO_NUCLEUS_XNVDSO_H */
diff --git a/ksrc/nucleus/module.c b/ksrc/nucleus/module.c
index 5404182..0a17661 100644
--- a/ksrc/nucleus/module.c
+++ b/ksrc/nucleus/module.c
@@ -35,6 +35,11 @@
 #endif /* CONFIG_XENO_OPT_PIPE */
 #include <nucleus/select.h>
 #include <asm/xenomai/bits/init.h>
+#ifdef CONFIG_XENO_OPT_PERVASIVE
+#include <nucleus/xnvdso.h>
+#else
+static inline void xnheap_init_vdso(void) { }
+#endif /* CONFIG_XENO_OPT_PERVASIVE */
 
 MODULE_DESCRIPTION("Xenomai nucleus");
 MODULE_AUTHOR("r...@xenomai.org");
@@ -106,6 +111,8 @@ int __init __xeno_sys_init(void)
                goto cleanup_arch;
 
        xnheap_set_label(&__xnsys_global_ppd.sem_heap, "global sem heap");
+
+       xnheap_init_vdso();
 #endif
        
 #ifdef __KERNEL__
diff --git a/ksrc/nucleus/shadow.c b/ksrc/nucleus/shadow.c
index d0cb416..bff7dc5 100644
--- a/ksrc/nucleus/shadow.c
+++ b/ksrc/nucleus/shadow.c
@@ -50,6 +50,7 @@
 #include <nucleus/trace.h>
 #include <nucleus/stat.h>
 #include <nucleus/sys_ppd.h>
+#include <nucleus/xnvdso.h>
 #include <asm/xenomai/features.h>
 #include <asm/xenomai/syscall.h>
 #include <asm/xenomai/bits/shadow.h>
@@ -693,6 +694,24 @@ void xnshadow_clear_sig(xnthread_t *thread, unsigned muxid)
 }
 EXPORT_SYMBOL_GPL(xnshadow_clear_sig);
 
+struct xnvdso *xnvdso;
+EXPORT_SYMBOL_GPL(xnvdso);
+
+/*
+ * We re-use the global semaphore heap to provide a multi-purpose shared
+ * memory area between Xenomai and Linux - for both kernel and userland
+ */
+void __init xnheap_init_vdso(void)
+{
+       xnvdso = (struct xnvdso *)xnheap_alloc(&__xnsys_global_ppd.sem_heap,
+                                                 sizeof(*xnvdso));
+
+       if (!xnvdso)
+               xnpod_fatal("Xenomai: cannot allocate memory for xnvdso!\n");
+
+       xnvdso->features = XNVDSO_FEATURES;
+}
+
 static inline void handle_rt_signals(xnthread_t *thread,
                                     struct pt_regs *regs,
                                     int sysflags)
@@ -1746,6 +1765,9 @@ static int xnshadow_sys_info(struct pt_regs *regs)
 
        info.cpufreq = xnarch_get_cpu_freq();
 
+       info.xnvdso_off =
+         xnheap_mapped_offset(&xnsys_ppd_get(1)->sem_heap, xnvdso);
+
        return __xn_safe_copy_to_user((void __user *)infarg, &info, 
sizeof(info));
 }
 


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