gcov: move gcov structs definitions to a gcc version specific file

Since also the gcov structures(gcov_info, gcov_fn_info, gcov_ctr_info) can
change between gcc releases, as shown in gcc 4.7, they cannot be defined
in a common header and need to be moved to a specific gcc implemention
file.  This also requires to make the gcov_info structure opaque for the
common code and to introduce simple helpers for accessing data inside
gcov_info.

Signed-off-by: Frantisek Hrbata <fhrbata@redhat.com>
Cc: Jan Stancek <jstancek@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Acked-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Andy Gospodarek <agospoda@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 153 insertions, 80 deletions

diff --git a/kernel/gcov/base.c b/kernel/gcov/base.c
index 9b22d03cc581..912576a671d8 100644
--- a/kernel/gcov/base.c
+++ b/kernel/gcov/base.c
@@ -20,7 +20,6 @@
 #include <linux/mutex.h>
 #include "gcov.h"
 
-static struct gcov_info *gcov_info_head;
 static int gcov_events_enabled;
 static DEFINE_MUTEX(gcov_lock);
 
@@ -34,7 +33,7 @@ void __gcov_init(struct gcov_info *info)
 
         mutex_lock(&gcov_lock);
         if (gcov_version == 0) {
-                gcov_version = info->version;
+                gcov_version = gcov_info_version(info);
                 /*
                  * Printing gcc's version magic may prove useful for debugging
                  * incompatibility reports.
@@ -45,8 +44,7 @@ void __gcov_init(struct gcov_info *info)
          * Add new profiling data structure to list and inform event
          * listener.
          */
-        info->next = gcov_info_head;
-        gcov_info_head = info;
+        gcov_info_link(info);
         if (gcov_events_enabled)
                 gcov_event(GCOV_ADD, info);
         mutex_unlock(&gcov_lock);
@@ -91,13 +89,15 @@ EXPORT_SYMBOL(__gcov_merge_delta);
  */
 void gcov_enable_events(void)
 {
-        struct gcov_info *info;
+        struct gcov_info *info = NULL;
 
         mutex_lock(&gcov_lock);
         gcov_events_enabled = 1;
+
         /* Perform event callback for previously registered entries. */
-        for (info = gcov_info_head; info; info = info->next)
+        while ((info = gcov_info_next(info)))
                 gcov_event(GCOV_ADD, info);
+
         mutex_unlock(&gcov_lock);
 }
 
@@ -112,25 +112,23 @@ static int gcov_module_notifier(struct notifier_block *nb, unsigned long event,
                                 void *data)
 {
         struct module *mod = data;
-        struct gcov_info *info;
-        struct gcov_info *prev;
+        struct gcov_info *info = NULL;
+        struct gcov_info *prev = NULL;
 
         if (event != MODULE_STATE_GOING)
                 return NOTIFY_OK;
         mutex_lock(&gcov_lock);
-        prev = NULL;
+
         /* Remove entries located in module from linked list. */
-        for (info = gcov_info_head; info; info = info->next) {
+        while ((info = gcov_info_next(info))) {
                 if (within(info, mod->module_core, mod->core_size)) {
-                        if (prev)
-                                prev->next = info->next;
-                        else
-                                gcov_info_head = info->next;
+                        gcov_info_unlink(prev, info);
                         if (gcov_events_enabled)
                                 gcov_event(GCOV_REMOVE, info);
                 } else
                         prev = info;
         }
+
         mutex_unlock(&gcov_lock);
 
         return NOTIFY_OK;
diff --git a/kernel/gcov/fs.c b/kernel/gcov/fs.c
index 7a7d2ee96d42..b49dfce8e8a1 100644
--- a/kernel/gcov/fs.c
+++ b/kernel/gcov/fs.c
@@ -242,7 +242,7 @@ static struct gcov_node *get_node_by_name(const char *name)
 
         list_for_each_entry(node, &all_head, all) {
                 info = get_node_info(node);
-                if (info && (strcmp(info->filename, name) == 0))
+                if (info && (strcmp(gcov_info_filename(info), name) == 0))
                         return node;
         }
 
@@ -279,7 +279,7 @@ static ssize_t gcov_seq_write(struct file *file, const char __user *addr,
         seq = file->private_data;
         info = gcov_iter_get_info(seq->private);
         mutex_lock(&node_lock);
-        node = get_node_by_name(info->filename);
+        node = get_node_by_name(gcov_info_filename(info));
         if (node) {
                 /* Reset counts or remove node for unloaded modules. */
                 if (node->num_loaded == 0)
@@ -376,8 +376,9 @@ static void add_links(struct gcov_node *node, struct dentry *parent)
         if (!node->links)
                 return;
         for (i = 0; i < num; i++) {
-                target = get_link_target(get_node_info(node)->filename,
-                                         &gcov_link[i]);
+                target = get_link_target(
+                                gcov_info_filename(get_node_info(node)),
+                                &gcov_link[i]);
                 if (!target)
                         goto out_err;
                 basename = strrchr(target, '/');
@@ -576,7 +577,7 @@ static void add_node(struct gcov_info *info)
         struct gcov_node *parent;
         struct gcov_node *node;
 
-        filename = kstrdup(info->filename, GFP_KERNEL);
+        filename = kstrdup(gcov_info_filename(info), GFP_KERNEL);
         if (!filename)
                 return;
         parent = &root_node;
@@ -631,7 +632,7 @@ static void add_info(struct gcov_node *node, struct gcov_info *info)
         loaded_info = kcalloc(num + 1, sizeof(struct gcov_info *), GFP_KERNEL);
         if (!loaded_info) {
                 pr_warning("could not add '%s' (out of memory)\n",
-                           info->filename);
+                           gcov_info_filename(info));
                 return;
         }
         memcpy(loaded_info, node->loaded_info,
@@ -645,7 +646,8 @@ static void add_info(struct gcov_node *node, struct gcov_info *info)
                  */
                 if (!gcov_info_is_compatible(node->unloaded_info, info)) {
                         pr_warning("discarding saved data for %s "
-                                   "(incompatible version)\n", info->filename);
+                                   "(incompatible version)\n",
+                                   gcov_info_filename(info));
                         gcov_info_free(node->unloaded_info);
                         node->unloaded_info = NULL;
                 }
@@ -656,7 +658,7 @@ static void add_info(struct gcov_node *node, struct gcov_info *info)
                  */
                 if (!gcov_info_is_compatible(node->loaded_info[0], info)) {
                         pr_warning("could not add '%s' (incompatible "
-                                   "version)\n", info->filename);
+                                   "version)\n", gcov_info_filename(info));
                         kfree(loaded_info);
                         return;
                 }
@@ -692,7 +694,8 @@ static void save_info(struct gcov_node *node, struct gcov_info *info)
                 node->unloaded_info = gcov_info_dup(info);
                 if (!node->unloaded_info) {
                         pr_warning("could not save data for '%s' "
-                                   "(out of memory)\n", info->filename);
+                                   "(out of memory)\n",
+                                   gcov_info_filename(info));
                 }
         }
 }
@@ -708,7 +711,7 @@ static void remove_info(struct gcov_node *node, struct gcov_info *info)
         i = get_info_index(node, info);
         if (i < 0) {
                 pr_warning("could not remove '%s' (not found)\n",
-                           info->filename);
+                           gcov_info_filename(info));
                 return;
         }
         if (gcov_persist)
@@ -735,7 +738,7 @@ void gcov_event(enum gcov_action action, struct gcov_info *info)
         struct gcov_node *node;
 
         mutex_lock(&node_lock);
-        node = get_node_by_name(info->filename);
+        node = get_node_by_name(gcov_info_filename(info));
         switch (action) {
         case GCOV_ADD:
                 if (node)
@@ -748,7 +751,7 @@ void gcov_event(enum gcov_action action, struct gcov_info *info)
                         remove_info(node, info);
                 else {
                         pr_warning("could not remove '%s' (not found)\n",
-                                   info->filename);
+                                   gcov_info_filename(info));
                 }
                 break;
         }
diff --git a/kernel/gcov/gcc_3_4.c b/kernel/gcov/gcc_3_4.c
index ae5bb4260033..27bc88a35013 100644
--- a/kernel/gcov/gcc_3_4.c
+++ b/kernel/gcov/gcc_3_4.c
@@ -21,6 +21,121 @@
 #include <linux/vmalloc.h>
 #include "gcov.h"
 
+#define GCOV_COUNTERS           5
+
+static struct gcov_info *gcov_info_head;
+
+/**
+ * struct gcov_fn_info - profiling meta data per function
+ * @ident: object file-unique function identifier
+ * @checksum: function checksum
+ * @n_ctrs: number of values per counter type belonging to this function
+ *
+ * This data is generated by gcc during compilation and doesn't change
+ * at run-time.
+ */
+struct gcov_fn_info {
+        unsigned int ident;
+        unsigned int checksum;
+        unsigned int n_ctrs[0];
+};
+
+/**
+ * struct gcov_ctr_info - profiling data per counter type
+ * @num: number of counter values for this type
+ * @values: array of counter values for this type
+ * @merge: merge function for counter values of this type (unused)
+ *
+ * This data is generated by gcc during compilation and doesn't change
+ * at run-time with the exception of the values array.
+ */
+struct gcov_ctr_info {
+        unsigned int    num;
+        gcov_type       *values;
+        void            (*merge)(gcov_type *, unsigned int);
+};
+
+/**
+ * struct gcov_info - profiling data per object file
+ * @version: gcov version magic indicating the gcc version used for compilation
+ * @next: list head for a singly-linked list
+ * @stamp: time stamp
+ * @filename: name of the associated gcov data file
+ * @n_functions: number of instrumented functions
+ * @functions: function data
+ * @ctr_mask: mask specifying which counter types are active
+ * @counts: counter data per counter type
+ *
+ * This data is generated by gcc during compilation and doesn't change
+ * at run-time with the exception of the next pointer.
+ */
+struct gcov_info {
+        unsigned int                    version;
+        struct gcov_info                *next;
+        unsigned int                    stamp;
+        const char                      *filename;
+        unsigned int                    n_functions;
+        const struct gcov_fn_info       *functions;
+        unsigned int                    ctr_mask;
+        struct gcov_ctr_info            counts[0];
+};
+
+/**
+ * gcov_info_filename - return info filename
+ * @info: profiling data set
+ */
+const char *gcov_info_filename(struct gcov_info *info)
+{
+        return info->filename;
+}
+
+/**
+ * gcov_info_version - return info version
+ * @info: profiling data set
+ */
+unsigned int gcov_info_version(struct gcov_info *info)
+{
+        return info->version;
+}
+
+/**
+ * gcov_info_next - return next profiling data set
+ * @info: profiling data set
+ *
+ * Returns next gcov_info following @info or first gcov_info in the chain if
+ * @info is %NULL.
+ */
+struct gcov_info *gcov_info_next(struct gcov_info *info)
+{
+        if (!info)
+                return gcov_info_head;
+
+        return info->next;
+}
+
+/**
+ * gcov_info_link - link/add profiling data set to the list
+ * @info: profiling data set
+ */
+void gcov_info_link(struct gcov_info *info)
+{
+        info->next = gcov_info_head;
+        gcov_info_head = info;
+}
+
+/**
+ * gcov_info_unlink - unlink/remove profiling data set from the list
+ * @prev: previous profiling data set
+ * @info: profiling data set
+ */
+void gcov_info_unlink(struct gcov_info *prev, struct gcov_info *info)
+{
+        if (prev)
+                prev->next = info->next;
+        else
+                gcov_info_head = info->next;
+}
+
 /* Symbolic links to be created for each profiling data file. */
 const struct gcov_link gcov_link[] = {
         { OBJ_TREE, "gcno" },   /* Link to .gcno file in $(objtree). */
diff --git a/kernel/gcov/gcov.h b/kernel/gcov/gcov.h
index 060073ebf7a6..92c8e22a29ed 100644
--- a/kernel/gcov/gcov.h
+++ b/kernel/gcov/gcov.h
@@ -21,7 +21,6 @@
  * gcc and need to be kept as close to the original definition as possible to
  * remain compatible.
  */
-#define GCOV_COUNTERS           5
 #define GCOV_DATA_MAGIC         ((unsigned int) 0x67636461)
 #define GCOV_TAG_FUNCTION       ((unsigned int) 0x01000000)
 #define GCOV_TAG_COUNTER_BASE   ((unsigned int) 0x01a10000)
@@ -34,60 +33,18 @@ typedef long gcov_type;
 typedef long long gcov_type;
 #endif
 
-/**
- * struct gcov_fn_info - profiling meta data per function
- * @ident: object file-unique function identifier
- * @checksum: function checksum
- * @n_ctrs: number of values per counter type belonging to this function
- *
- * This data is generated by gcc during compilation and doesn't change
- * at run-time.
- */
-struct gcov_fn_info {
-        unsigned int ident;
-        unsigned int checksum;
-        unsigned int n_ctrs[0];
-};
-
-/**
- * struct gcov_ctr_info - profiling data per counter type
- * @num: number of counter values for this type
- * @values: array of counter values for this type
- * @merge: merge function for counter values of this type (unused)
- *
- * This data is generated by gcc during compilation and doesn't change
- * at run-time with the exception of the values array.
- */
-struct gcov_ctr_info {
-        unsigned int    num;
-        gcov_type       *values;
-        void            (*merge)(gcov_type *, unsigned int);
-};
+/* Opaque gcov_info. The gcov structures can change as for example in gcc 4.7 so
+ * we cannot use full definition here and they need to be placed in gcc specific
+ * implementation of gcov. This also means no direct access to the members in
+ * generic code and usage of the interface below.*/
+struct gcov_info;
 
-/**
- * struct gcov_info - profiling data per object file
- * @version: gcov version magic indicating the gcc version used for compilation
- * @next: list head for a singly-linked list
- * @stamp: time stamp
- * @filename: name of the associated gcov data file
- * @n_functions: number of instrumented functions
- * @functions: function data
- * @ctr_mask: mask specifying which counter types are active
- * @counts: counter data per counter type
- *
- * This data is generated by gcc during compilation and doesn't change
- * at run-time with the exception of the next pointer.
- */
-struct gcov_info {
-        unsigned int                    version;
-        struct gcov_info                *next;
-        unsigned int                    stamp;
-        const char                      *filename;
-        unsigned int                    n_functions;
-        const struct gcov_fn_info       *functions;
-        unsigned int                    ctr_mask;
-        struct gcov_ctr_info            counts[0];
-};
+/* Interface to access gcov_info data  */
+const char *gcov_info_filename(struct gcov_info *info);
+unsigned int gcov_info_version(struct gcov_info *info);
+struct gcov_info *gcov_info_next(struct gcov_info *info);
+void gcov_info_link(struct gcov_info *info);
+void gcov_info_unlink(struct gcov_info *prev, struct gcov_info *info);
 
 /* Base interface. */
 enum gcov_action {