Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=8256e47cdc8923e9959eb1d7f95d80da538add80
Commit:     8256e47cdc8923e9959eb1d7f95d80da538add80
Parent:     09cadedbdc01f1a4bea1f427d4fb4642eaa19da9
Author:     Mathieu Desnoyers <[EMAIL PROTECTED]>
AuthorDate: Thu Oct 18 23:41:06 2007 -0700
Committer:  Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Fri Oct 19 11:53:54 2007 -0700

    Linux Kernel Markers
    
    The marker activation functions sits in kernel/marker.c.  A hash table is 
used
    to keep track of the registered probes and armed markers, so the markers
    within a newly loaded module that should be active can be activated at 
module
    load time.
    
    marker_query has been removed. marker_get_first, marker_get_next and
    marker_release should be used as iterators on the markers.
    
    [EMAIL PROTECTED]: coding-style fixes]
    Signed-off-by: Mathieu Desnoyers <[EMAIL PROTECTED]>
    Acked-by: "Frank Ch. Eigler" <[EMAIL PROTECTED]>
    Cc: Christoph Hellwig <[EMAIL PROTECTED]>
    Cc: Rusty Russell <[EMAIL PROTECTED]>
    Cc: Mike Mason <[EMAIL PROTECTED]>
    Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
    Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
 include/asm-generic/vmlinux.lds.h |    7 +-
 include/linux/marker.h            |  130 +++++++++
 include/linux/module.h            |   12 +
 kernel/Kconfig.instrumentation    |    6 +
 kernel/Makefile                   |    1 +
 kernel/marker.c                   |  525 +++++++++++++++++++++++++++++++++++++
 kernel/module.c                   |   30 ++
 7 files changed, 710 insertions(+), 1 deletions(-)

diff --git a/include/asm-generic/vmlinux.lds.h 
b/include/asm-generic/vmlinux.lds.h
index 5615440..9f584cc 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -12,7 +12,11 @@
 /* .data section */
 #define DATA_DATA                                                      \
        *(.data)                                                        \
-       *(.data.init.refok)
+       *(.data.init.refok)                                             \
+       . = ALIGN(8);                                                   \
+       VMLINUX_SYMBOL(__start___markers) = .;                          \
+       *(__markers)                                                    \
+       VMLINUX_SYMBOL(__stop___markers) = .;
 
 #define RO_DATA(align)                                                 \
        . = ALIGN((align));                                             \
@@ -20,6 +24,7 @@
                VMLINUX_SYMBOL(__start_rodata) = .;                     \
                *(.rodata) *(.rodata.*)                                 \
                *(__vermagic)           /* Kernel version magic */      \
+               *(__markers_strings)    /* Markers: strings */          \
        }                                                               \
                                                                        \
        .rodata1          : AT(ADDR(.rodata1) - LOAD_OFFSET) {          \
diff --git a/include/linux/marker.h b/include/linux/marker.h
new file mode 100644
index 0000000..8038d89
--- /dev/null
+++ b/include/linux/marker.h
@@ -0,0 +1,130 @@
+#ifndef _LINUX_MARKER_H
+#define _LINUX_MARKER_H
+
+/*
+ * Code markup for dynamic and static tracing.
+ *
+ * See Documentation/marker.txt.
+ *
+ * (C) Copyright 2006 Mathieu Desnoyers <[EMAIL PROTECTED]>
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <linux/types.h>
+
+struct module;
+struct marker;
+
+/**
+ * marker_probe_func - Type of a marker probe function
+ * @mdata: pointer of type struct marker
+ * @private_data: caller site private data
+ * @fmt: format string
+ * @...: variable argument list
+ *
+ * Type of marker probe functions. They receive the mdata and need to parse the
+ * format string to recover the variable argument list.
+ */
+typedef void marker_probe_func(const struct marker *mdata,
+       void *private_data, const char *fmt, ...);
+
+struct marker {
+       const char *name;       /* Marker name */
+       const char *format;     /* Marker format string, describing the
+                                * variable argument list.
+                                */
+       char state;             /* Marker state. */
+       marker_probe_func *call;/* Probe handler function pointer */
+       void *private;          /* Private probe data */
+} __attribute__((aligned(8)));
+
+#ifdef CONFIG_MARKERS
+
+/*
+ * Note : the empty asm volatile with read constraint is used here instead of a
+ * "used" attribute to fix a gcc 4.1.x bug.
+ * Make sure the alignment of the structure in the __markers section will
+ * not add unwanted padding between the beginning of the section and the
+ * structure. Force alignment to the same alignment as the section start.
+ */
+#define __trace_mark(name, call_data, format, args...)                 \
+       do {                                                            \
+               static const char __mstrtab_name_##name[]               \
+               __attribute__((section("__markers_strings")))           \
+               = #name;                                                \
+               static const char __mstrtab_format_##name[]             \
+               __attribute__((section("__markers_strings")))           \
+               = format;                                               \
+               static struct marker __mark_##name                      \
+               __attribute__((section("__markers"), aligned(8))) =     \
+               { __mstrtab_name_##name, __mstrtab_format_##name,       \
+               0, __mark_empty_function, NULL };                       \
+               asm volatile("" : : "i" (&__mark_##name));              \
+               __mark_check_format(format, ## args);                   \
+               if (unlikely(__mark_##name.state)) {                    \
+                       preempt_disable();                              \
+                       (*__mark_##name.call)                           \
+                               (&__mark_##name, call_data,             \
+                               format, ## args);                       \
+                       preempt_enable();                               \
+               }                                                       \
+       } while (0)
+
+extern void marker_update_probe_range(struct marker *begin,
+       struct marker *end, struct module *probe_module, int *refcount);
+#else /* !CONFIG_MARKERS */
+#define __trace_mark(name, call_data, format, args...) \
+               __mark_check_format(format, ## args)
+static inline void marker_update_probe_range(struct marker *begin,
+       struct marker *end, struct module *probe_module, int *refcount)
+{ }
+#endif /* CONFIG_MARKERS */
+
+/**
+ * trace_mark - Marker
+ * @name: marker name, not quoted.
+ * @format: format string
+ * @args...: variable argument list
+ *
+ * Places a marker.
+ */
+#define trace_mark(name, format, args...) \
+       __trace_mark(name, NULL, format, ## args)
+
+#define MARK_MAX_FORMAT_LEN    1024
+
+/**
+ * MARK_NOARGS - Format string for a marker with no argument.
+ */
+#define MARK_NOARGS " "
+
+/* To be used for string format validity checking with gcc */
+static inline void __printf(1, 2) __mark_check_format(const char *fmt, ...)
+{
+}
+
+extern marker_probe_func __mark_empty_function;
+
+/*
+ * Connect a probe to a marker.
+ * private data pointer must be a valid allocated memory address, or NULL.
+ */
+extern int marker_probe_register(const char *name, const char *format,
+                               marker_probe_func *probe, void *private);
+
+/*
+ * Returns the private data given to marker_probe_register.
+ */
+extern void *marker_probe_unregister(const char *name);
+/*
+ * Unregister a marker by providing the registered private data.
+ */
+extern void *marker_probe_unregister_private_data(void *private);
+
+extern int marker_arm(const char *name);
+extern int marker_disarm(const char *name);
+extern void *marker_get_private_data(const char *name);
+
+#endif
diff --git a/include/linux/module.h b/include/linux/module.h
index 642f325..2cbc0b8 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -15,6 +15,7 @@
 #include <linux/stringify.h>
 #include <linux/kobject.h>
 #include <linux/moduleparam.h>
+#include <linux/marker.h>
 #include <asm/local.h>
 
 #include <asm/module.h>
@@ -354,6 +355,10 @@ struct module
        /* The command line arguments (may be mangled).  People like
           keeping pointers to this stuff */
        char *args;
+#ifdef CONFIG_MARKERS
+       struct marker *markers;
+       unsigned int num_markers;
+#endif
 };
 #ifndef MODULE_ARCH_INIT
 #define MODULE_ARCH_INIT {}
@@ -457,6 +462,8 @@ int unregister_module_notifier(struct notifier_block * nb);
 
 extern void print_modules(void);
 
+extern void module_update_markers(struct module *probe_module, int *refcount);
+
 #else /* !CONFIG_MODULES... */
 #define EXPORT_SYMBOL(sym)
 #define EXPORT_SYMBOL_GPL(sym)
@@ -556,6 +563,11 @@ static inline void print_modules(void)
 {
 }
 
+static inline void module_update_markers(struct module *probe_module,
+               int *refcount)
+{
+}
+
 #endif /* CONFIG_MODULES */
 
 struct device_driver;
diff --git a/kernel/Kconfig.instrumentation b/kernel/Kconfig.instrumentation
index ba5c05c..f5f2c76 100644
--- a/kernel/Kconfig.instrumentation
+++ b/kernel/Kconfig.instrumentation
@@ -40,4 +40,10 @@ config KPROBES
          for kernel debugging, non-intrusive instrumentation and testing.
          If in doubt, say "N".
 
+config MARKERS
+       bool "Activate markers"
+       help
+         Place an empty function call at each marker site. Can be
+         dynamically changed for a probe function.
+
 endif # INSTRUMENTATION
diff --git a/kernel/Makefile b/kernel/Makefile
index 32b2d8b..05c3e6d 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -55,6 +55,7 @@ obj-$(CONFIG_RELAY) += relay.o
 obj-$(CONFIG_SYSCTL) += utsname_sysctl.o
 obj-$(CONFIG_TASK_DELAY_ACCT) += delayacct.o
 obj-$(CONFIG_TASKSTATS) += taskstats.o tsacct.o
+obj-$(CONFIG_MARKERS) += marker.o
 
 ifneq ($(CONFIG_SCHED_NO_NO_OMIT_FRAME_POINTER),y)
 # According to Alan Modra <[EMAIL PROTECTED]>, the -fno-omit-frame-pointer is
diff --git a/kernel/marker.c b/kernel/marker.c
new file mode 100644
index 0000000..ccb48d9
--- /dev/null
+++ b/kernel/marker.c
@@ -0,0 +1,525 @@
+/*
+ * Copyright (C) 2007 Mathieu Desnoyers
+ *
+ * This program 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.
+ *
+ * This program 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 this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/types.h>
+#include <linux/jhash.h>
+#include <linux/list.h>
+#include <linux/rcupdate.h>
+#include <linux/marker.h>
+#include <linux/err.h>
+
+extern struct marker __start___markers[];
+extern struct marker __stop___markers[];
+
+/*
+ * module_mutex nests inside markers_mutex. Markers mutex protects the builtin
+ * and module markers, the hash table and deferred_sync.
+ */
+static DEFINE_MUTEX(markers_mutex);
+
+/*
+ * Marker deferred synchronization.
+ * Upon marker probe_unregister, we delay call to synchronize_sched() to
+ * accelerate mass unregistration (only when there is no more reference to a
+ * given module do we call synchronize_sched()). However, we need to make sure
+ * every critical region has ended before we re-arm a marker that has been
+ * unregistered and then registered back with a different probe data.
+ */
+static int deferred_sync;
+
+/*
+ * Marker hash table, containing the active markers.
+ * Protected by module_mutex.
+ */
+#define MARKER_HASH_BITS 6
+#define MARKER_TABLE_SIZE (1 << MARKER_HASH_BITS)
+
+struct marker_entry {
+       struct hlist_node hlist;
+       char *format;
+       marker_probe_func *probe;
+       void *private;
+       int refcount;   /* Number of times armed. 0 if disarmed. */
+       char name[0];   /* Contains name'\0'format'\0' */
+};
+
+static struct hlist_head marker_table[MARKER_TABLE_SIZE];
+
+/**
+ * __mark_empty_function - Empty probe callback
+ * @mdata: pointer of type const struct marker
+ * @fmt: format string
+ * @...: variable argument list
+ *
+ * Empty callback provided as a probe to the markers. By providing this to a
+ * disabled marker, we make sure the  execution flow is always valid even
+ * though the function pointer change and the marker enabling are two distinct
+ * operations that modifies the execution flow of preemptible code.
+ */
+void __mark_empty_function(const struct marker *mdata, void *private,
+       const char *fmt, ...)
+{
+}
+EXPORT_SYMBOL_GPL(__mark_empty_function);
+
+/*
+ * Get marker if the marker is present in the marker hash table.
+ * Must be called with markers_mutex held.
+ * Returns NULL if not present.
+ */
+static struct marker_entry *get_marker(const char *name)
+{
+       struct hlist_head *head;
+       struct hlist_node *node;
+       struct marker_entry *e;
+       u32 hash = jhash(name, strlen(name), 0);
+
+       head = &marker_table[hash & ((1 << MARKER_HASH_BITS)-1)];
+       hlist_for_each_entry(e, node, head, hlist) {
+               if (!strcmp(name, e->name))
+                       return e;
+       }
+       return NULL;
+}
+
+/*
+ * Add the marker to the marker hash table. Must be called with markers_mutex
+ * held.
+ */
+static int add_marker(const char *name, const char *format,
+       marker_probe_func *probe, void *private)
+{
+       struct hlist_head *head;
+       struct hlist_node *node;
+       struct marker_entry *e;
+       size_t name_len = strlen(name) + 1;
+       size_t format_len = 0;
+       u32 hash = jhash(name, name_len-1, 0);
+
+       if (format)
+               format_len = strlen(format) + 1;
+       head = &marker_table[hash & ((1 << MARKER_HASH_BITS)-1)];
+       hlist_for_each_entry(e, node, head, hlist) {
+               if (!strcmp(name, e->name)) {
+                       printk(KERN_NOTICE
+                               "Marker %s busy, probe %p already installed\n",
+                               name, e->probe);
+                       return -EBUSY;  /* Already there */
+               }
+       }
+       /*
+        * Using kmalloc here to allocate a variable length element. Could
+        * cause some memory fragmentation if overused.
+        */
+       e = kmalloc(sizeof(struct marker_entry) + name_len + format_len,
+                       GFP_KERNEL);
+       if (!e)
+               return -ENOMEM;
+       memcpy(&e->name[0], name, name_len);
+       if (format) {
+               e->format = &e->name[name_len];
+               memcpy(e->format, format, format_len);
+               trace_mark(core_marker_format, "name %s format %s",
+                               e->name, e->format);
+       } else
+               e->format = NULL;
+       e->probe = probe;
+       e->private = private;
+       e->refcount = 0;
+       hlist_add_head(&e->hlist, head);
+       return 0;
+}
+
+/*
+ * Remove the marker from the marker hash table. Must be called with mutex_lock
+ * held.
+ */
+static void *remove_marker(const char *name)
+{
+       struct hlist_head *head;
+       struct hlist_node *node;
+       struct marker_entry *e;
+       int found = 0;
+       size_t len = strlen(name) + 1;
+       void *private = NULL;
+       u32 hash = jhash(name, len-1, 0);
+
+       head = &marker_table[hash & ((1 << MARKER_HASH_BITS)-1)];
+       hlist_for_each_entry(e, node, head, hlist) {
+               if (!strcmp(name, e->name)) {
+                       found = 1;
+                       break;
+               }
+       }
+       if (found) {
+               private = e->private;
+               hlist_del(&e->hlist);
+               kfree(e);
+       }
+       return private;
+}
+
+/*
+ * Set the mark_entry format to the format found in the element.
+ */
+static int marker_set_format(struct marker_entry **entry, const char *format)
+{
+       struct marker_entry *e;
+       size_t name_len = strlen((*entry)->name) + 1;
+       size_t format_len = strlen(format) + 1;
+
+       e = kmalloc(sizeof(struct marker_entry) + name_len + format_len,
+                       GFP_KERNEL);
+       if (!e)
+               return -ENOMEM;
+       memcpy(&e->name[0], (*entry)->name, name_len);
+       e->format = &e->name[name_len];
+       memcpy(e->format, format, format_len);
+       e->probe = (*entry)->probe;
+       e->private = (*entry)->private;
+       e->refcount = (*entry)->refcount;
+       hlist_add_before(&e->hlist, &(*entry)->hlist);
+       hlist_del(&(*entry)->hlist);
+       kfree(*entry);
+       *entry = e;
+       trace_mark(core_marker_format, "name %s format %s",
+                       e->name, e->format);
+       return 0;
+}
+
+/*
+ * Sets the probe callback corresponding to one marker.
+ */
+static int set_marker(struct marker_entry **entry, struct marker *elem)
+{
+       int ret;
+       WARN_ON(strcmp((*entry)->name, elem->name) != 0);
+
+       if ((*entry)->format) {
+               if (strcmp((*entry)->format, elem->format) != 0) {
+                       printk(KERN_NOTICE
+                               "Format mismatch for probe %s "
+                               "(%s), marker (%s)\n",
+                               (*entry)->name,
+                               (*entry)->format,
+                               elem->format);
+                       return -EPERM;
+               }
+       } else {
+               ret = marker_set_format(entry, elem->format);
+               if (ret)
+                       return ret;
+       }
+       elem->call = (*entry)->probe;
+       elem->private = (*entry)->private;
+       elem->state = 1;
+       return 0;
+}
+
+/*
+ * Disable a marker and its probe callback.
+ * Note: only after a synchronize_sched() issued after setting elem->call to 
the
+ * empty function insures that the original callback is not used anymore. This
+ * insured by preemption disabling around the call site.
+ */
+static void disable_marker(struct marker *elem)
+{
+       elem->state = 0;
+       elem->call = __mark_empty_function;
+       /*
+        * Leave the private data and id there, because removal is racy and
+        * should be done only after a synchronize_sched(). These are never used
+        * until the next initialization anyway.
+        */
+}
+
+/**
+ * marker_update_probe_range - Update a probe range
+ * @begin: beginning of the range
+ * @end: end of the range
+ * @probe_module: module address of the probe being updated
+ * @refcount: number of references left to the given probe_module (out)
+ *
+ * Updates the probe callback corresponding to a range of markers.
+ * Must be called with markers_mutex held.
+ */
+void marker_update_probe_range(struct marker *begin,
+       struct marker *end, struct module *probe_module,
+       int *refcount)
+{
+       struct marker *iter;
+       struct marker_entry *mark_entry;
+
+       for (iter = begin; iter < end; iter++) {
+               mark_entry = get_marker(iter->name);
+               if (mark_entry && mark_entry->refcount) {
+                       set_marker(&mark_entry, iter);
+                       /*
+                        * ignore error, continue
+                        */
+                       if (probe_module)
+                               if (probe_module ==
+                       __module_text_address((unsigned long)mark_entry->probe))
+                                       (*refcount)++;
+               } else {
+                       disable_marker(iter);
+               }
+       }
+}
+
+/*
+ * Update probes, removing the faulty probes.
+ * Issues a synchronize_sched() when no reference to the module passed
+ * as parameter is found in the probes so the probe module can be
+ * safely unloaded from now on.
+ */
+static void marker_update_probes(struct module *probe_module)
+{
+       int refcount = 0;
+
+       mutex_lock(&markers_mutex);
+       /* Core kernel markers */
+       marker_update_probe_range(__start___markers,
+                       __stop___markers, probe_module, &refcount);
+       /* Markers in modules. */
+       module_update_markers(probe_module, &refcount);
+       if (probe_module && refcount == 0) {
+               synchronize_sched();
+               deferred_sync = 0;
+       }
+       mutex_unlock(&markers_mutex);
+}
+
+/**
+ * marker_probe_register -  Connect a probe to a marker
+ * @name: marker name
+ * @format: format string
+ * @probe: probe handler
+ * @private: probe private data
+ *
+ * private data must be a valid allocated memory address, or NULL.
+ * Returns 0 if ok, error value on error.
+ */
+int marker_probe_register(const char *name, const char *format,
+                       marker_probe_func *probe, void *private)
+{
+       struct marker_entry *entry;
+       int ret = 0, need_update = 0;
+
+       mutex_lock(&markers_mutex);
+       entry = get_marker(name);
+       if (entry && entry->refcount) {
+               ret = -EBUSY;
+               goto end;
+       }
+       if (deferred_sync) {
+               synchronize_sched();
+               deferred_sync = 0;
+       }
+       ret = add_marker(name, format, probe, private);
+       if (ret)
+               goto end;
+       need_update = 1;
+end:
+       mutex_unlock(&markers_mutex);
+       if (need_update)
+               marker_update_probes(NULL);
+       return ret;
+}
+EXPORT_SYMBOL_GPL(marker_probe_register);
+
+/**
+ * marker_probe_unregister -  Disconnect a probe from a marker
+ * @name: marker name
+ *
+ * Returns the private data given to marker_probe_register, or an ERR_PTR().
+ */
+void *marker_probe_unregister(const char *name)
+{
+       struct module *probe_module;
+       struct marker_entry *entry;
+       void *private;
+       int need_update = 0;
+
+       mutex_lock(&markers_mutex);
+       entry = get_marker(name);
+       if (!entry) {
+               private = ERR_PTR(-ENOENT);
+               goto end;
+       }
+       entry->refcount = 0;
+       /* In what module is the probe handler ? */
+       probe_module = __module_text_address((unsigned long)entry->probe);
+       private = remove_marker(name);
+       deferred_sync = 1;
+       need_update = 1;
+end:
+       mutex_unlock(&markers_mutex);
+       if (need_update)
+               marker_update_probes(probe_module);
+       return private;
+}
+EXPORT_SYMBOL_GPL(marker_probe_unregister);
+
+/**
+ * marker_probe_unregister_private_data -  Disconnect a probe from a marker
+ * @private: probe private data
+ *
+ * Unregister a marker by providing the registered private data.
+ * Returns the private data given to marker_probe_register, or an ERR_PTR().
+ */
+void *marker_probe_unregister_private_data(void *private)
+{
+       struct module *probe_module;
+       struct hlist_head *head;
+       struct hlist_node *node;
+       struct marker_entry *entry;
+       int found = 0;
+       unsigned int i;
+       int need_update = 0;
+
+       mutex_lock(&markers_mutex);
+       for (i = 0; i < MARKER_TABLE_SIZE; i++) {
+               head = &marker_table[i];
+               hlist_for_each_entry(entry, node, head, hlist) {
+                       if (entry->private == private) {
+                               found = 1;
+                               goto iter_end;
+                       }
+               }
+       }
+iter_end:
+       if (!found) {
+               private = ERR_PTR(-ENOENT);
+               goto end;
+       }
+       entry->refcount = 0;
+       /* In what module is the probe handler ? */
+       probe_module = __module_text_address((unsigned long)entry->probe);
+       private = remove_marker(entry->name);
+       deferred_sync = 1;
+       need_update = 1;
+end:
+       mutex_unlock(&markers_mutex);
+       if (need_update)
+               marker_update_probes(probe_module);
+       return private;
+}
+EXPORT_SYMBOL_GPL(marker_probe_unregister_private_data);
+
+/**
+ * marker_arm - Arm a marker
+ * @name: marker name
+ *
+ * Activate a marker. It keeps a reference count of the number of
+ * arming/disarming done.
+ * Returns 0 if ok, error value on error.
+ */
+int marker_arm(const char *name)
+{
+       struct marker_entry *entry;
+       int ret = 0, need_update = 0;
+
+       mutex_lock(&markers_mutex);
+       entry = get_marker(name);
+       if (!entry) {
+               ret = -ENOENT;
+               goto end;
+       }
+       /*
+        * Only need to update probes when refcount passes from 0 to 1.
+        */
+       if (entry->refcount++)
+               goto end;
+       need_update = 1;
+end:
+       mutex_unlock(&markers_mutex);
+       if (need_update)
+               marker_update_probes(NULL);
+       return ret;
+}
+EXPORT_SYMBOL_GPL(marker_arm);
+
+/**
+ * marker_disarm - Disarm a marker
+ * @name: marker name
+ *
+ * Disarm a marker. It keeps a reference count of the number of 
arming/disarming
+ * done.
+ * Returns 0 if ok, error value on error.
+ */
+int marker_disarm(const char *name)
+{
+       struct marker_entry *entry;
+       int ret = 0, need_update = 0;
+
+       mutex_lock(&markers_mutex);
+       entry = get_marker(name);
+       if (!entry) {
+               ret = -ENOENT;
+               goto end;
+       }
+       /*
+        * Only permit decrement refcount if higher than 0.
+        * Do probe update only on 1 -> 0 transition.
+        */
+       if (entry->refcount) {
+               if (--entry->refcount)
+                       goto end;
+       } else {
+               ret = -EPERM;
+               goto end;
+       }
+       need_update = 1;
+end:
+       mutex_unlock(&markers_mutex);
+       if (need_update)
+               marker_update_probes(NULL);
+       return ret;
+}
+EXPORT_SYMBOL_GPL(marker_disarm);
+
+/**
+ * marker_get_private_data - Get a marker's probe private data
+ * @name: marker name
+ *
+ * Returns the private data pointer, or an ERR_PTR.
+ * The private data pointer should _only_ be dereferenced if the caller is the
+ * owner of the data, or its content could vanish. This is mostly used to
+ * confirm that a caller is the owner of a registered probe.
+ */
+void *marker_get_private_data(const char *name)
+{
+       struct hlist_head *head;
+       struct hlist_node *node;
+       struct marker_entry *e;
+       size_t name_len = strlen(name) + 1;
+       u32 hash = jhash(name, name_len-1, 0);
+       int found = 0;
+
+       head = &marker_table[hash & ((1 << MARKER_HASH_BITS)-1)];
+       hlist_for_each_entry(e, node, head, hlist) {
+               if (!strcmp(name, e->name)) {
+                       found = 1;
+                       return e->private;
+               }
+       }
+       return ERR_PTR(-ENOENT);
+}
+EXPORT_SYMBOL_GPL(marker_get_private_data);
diff --git a/kernel/module.c b/kernel/module.c
index 7734595..3202c99 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1673,6 +1673,8 @@ static struct module *load_module(void __user *umod,
        unsigned int unusedcrcindex;
        unsigned int unusedgplindex;
        unsigned int unusedgplcrcindex;
+       unsigned int markersindex;
+       unsigned int markersstringsindex;
        struct module *mod;
        long err = 0;
        void *percpu = NULL, *ptr = NULL; /* Stops spurious gcc warning */
@@ -1939,6 +1941,9 @@ static struct module *load_module(void __user *umod,
                add_taint_module(mod, TAINT_FORCED_MODULE);
        }
 #endif
+       markersindex = find_sec(hdr, sechdrs, secstrings, "__markers");
+       markersstringsindex = find_sec(hdr, sechdrs, secstrings,
+                                       "__markers_strings");
 
        /* Now do relocations. */
        for (i = 1; i < hdr->e_shnum; i++) {
@@ -1961,6 +1966,11 @@ static struct module *load_module(void __user *umod,
                if (err < 0)
                        goto cleanup;
        }
+#ifdef CONFIG_MARKERS
+       mod->markers = (void *)sechdrs[markersindex].sh_addr;
+       mod->num_markers =
+               sechdrs[markersindex].sh_size / sizeof(*mod->markers);
+#endif
 
         /* Find duplicate symbols */
        err = verify_export_symbols(mod);
@@ -1979,6 +1989,11 @@ static struct module *load_module(void __user *umod,
 
        add_kallsyms(mod, sechdrs, symindex, strindex, secstrings);
 
+#ifdef CONFIG_MARKERS
+       if (!mod->taints)
+               marker_update_probe_range(mod->markers,
+                       mod->markers + mod->num_markers, NULL, NULL);
+#endif
        err = module_finalize(hdr, sechdrs, mod);
        if (err < 0)
                goto cleanup;
@@ -2570,3 +2585,18 @@ EXPORT_SYMBOL(module_remove_driver);
 void struct_module(struct module *mod) { return; }
 EXPORT_SYMBOL(struct_module);
 #endif
+
+#ifdef CONFIG_MARKERS
+void module_update_markers(struct module *probe_module, int *refcount)
+{
+       struct module *mod;
+
+       mutex_lock(&module_mutex);
+       list_for_each_entry(mod, &modules, list)
+               if (!mod->taints)
+                       marker_update_probe_range(mod->markers,
+                               mod->markers + mod->num_markers,
+                               probe_module, refcount);
+       mutex_unlock(&module_mutex);
+}
+#endif
-
To unsubscribe from this list: send the line "unsubscribe git-commits-head" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to