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Subject[RFC PATCH 7/8] gcov: add gcov profiling infrastructure
From: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>

gcov profiling infrastructure:

* change kbuild to include profiling flags
* provide functions needed by profiling code
* present profiling data as files in debugfs

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
---
Makefile | 10
kernel/Makefile | 1
kernel/gcov/Kconfig | 44 +++
kernel/gcov/Makefile | 11
kernel/gcov/base.c | 152 +++++++++++
kernel/gcov/fs.c | 540 ++++++++++++++++++++++++++++++++++++++++
kernel/gcov/gcc_3_4.c | 374 +++++++++++++++++++++++++++
kernel/gcov/gcov.h | 101 +++++++
lib/Kconfig.debug | 1
scripts/Makefile.lib | 10
10 files changed, 1239 insertions(+), 5 deletions(-)

Index: linux-2.6.25/Makefile
===================================================================
--- linux-2.6.25.orig/Makefile
+++ linux-2.6.25/Makefile
@@ -320,6 +320,7 @@ AFLAGS_MODULE = $(MODFLAGS)
LDFLAGS_MODULE =
CFLAGS_KERNEL =
AFLAGS_KERNEL =
+CFLAGS_GCOV = -fprofile-arcs -ftest-coverage


# Use LINUXINCLUDE when you must reference the include/ directory.
@@ -345,7 +346,7 @@ export CPP AR NM STRIP OBJCOPY OBJDUMP M
export HOSTCXX HOSTCXXFLAGS LDFLAGS_MODULE CHECK CHECKFLAGS

export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS LDFLAGS
-export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE
+export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE CFLAGS_GCOV
export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE

# When compiling out-of-tree modules, put MODVERDIR in the module
@@ -1126,7 +1127,8 @@ clean: archclean $(clean-dirs)
@find . $(RCS_FIND_IGNORE) \
\( -name '*.[oas]' -o -name '*.ko' -o -name '.*.cmd' \
-o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \
- -o -name '*.symtypes' -o -name 'modules.order' \) \
+ -o -name '*.symtypes' -o -name 'modules.order' \
+ -o -name '*.gcno' \) \
-type f -print | xargs rm -f

# mrproper - Delete all generated files, including .config
@@ -1309,8 +1311,8 @@ clean: $(clean-dirs)
$(call cmd,rmfiles)
@find $(KBUILD_EXTMOD) $(RCS_FIND_IGNORE) \
\( -name '*.[oas]' -o -name '*.ko' -o -name '.*.cmd' \
- -o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \) \
- -type f -print | xargs rm -f
+ -o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \
+ -o -name '*.gcno' \) -type f -print | xargs rm -f

help:
@echo ' Building external modules.'
Index: linux-2.6.25/scripts/Makefile.lib
===================================================================
--- linux-2.6.25.orig/scripts/Makefile.lib
+++ linux-2.6.25/scripts/Makefile.lib
@@ -100,10 +100,18 @@ _c_flags = $(KBUILD_CFLAGS) $(ccfl
_a_flags = $(KBUILD_AFLAGS) $(asflags-y) $(AFLAGS_$(basetarget).o)
_cpp_flags = $(KBUILD_CPPFLAGS) $(cppflags-y) $(CPPFLAGS_$(@F))

+# Enable profiling flags for a file, directory or for all files depending on
+# variables GCOV_obj.o, GCOV and CONFIG_GCOV_PROFILE_ALL (in this order)
+ifeq ($(CONFIG_GCOV_PROFILE),y)
+_c_flags += $(if $(patsubst n%,, \
+ $(GCOV_$(basetarget).o)$(GCOV)$(CONFIG_GCOV_PROFILE_ALL)), \
+ $(CFLAGS_GCOV))
+endif
+
# If building the kernel in a separate objtree expand all occurrences
# of -Idir to -I$(srctree)/dir except for absolute paths (starting with '/').

-ifeq ($(KBUILD_SRC),)
+ifeq ($(KBUILD_SRC)$(CONFIG_GCOV_PROFILE),)
__c_flags = $(_c_flags)
__a_flags = $(_a_flags)
__cpp_flags = $(_cpp_flags)
Index: linux-2.6.25/kernel/gcov/Kconfig
===================================================================
--- /dev/null
+++ linux-2.6.25/kernel/gcov/Kconfig
@@ -0,0 +1,45 @@
+menu "GCOV profiling"
+
+config GCOV_PROFILE
+ bool "Activate gcov-based profiling"
+ depends on DEBUG_FS
+ ---help---
+ This option enables gcov-based code profiling (e.g. for code coverage
+ measurements).
+
+ If unsure, say N.
+
+ Additionally specify CONFIG_GCOV_PROFILE_ALL=y to get profiling data
+ for the entire kernel. To enable profiling for specific files or
+ directories, add a line similar to the following to the respective
+ Makefile:
+
+ For a single file (e.g. main.o):
+ GCOV_main.o := y
+
+ For all files in one directory:
+ GCOV := y
+
+ To exclude files from being profiled even when CONFIG_GCOV_PROFILE_ALL
+ is specified, use:
+
+ GCOV_main.o := n
+ and:
+ GCOV := n
+
+ Note that the debugfs filesystem has to be mounted to access
+ profiling data.
+
+config GCOV_PROFILE_ALL
+ bool "Profile entire Kernel"
+ depends on GCOV_PROFILE
+ ---help---
+ This options activates profiling for the entire kernel.
+
+ If unsure, say Y.
+
+ Note that a kernel compiled with profiling flags will be larger and
+ slower. Also be sure to exclude files from profiling which are not
+ linked to the kernel image to prevent linker errors.
+
+endmenu
Index: linux-2.6.25/kernel/gcov/base.c
===================================================================
--- /dev/null
+++ linux-2.6.25/kernel/gcov/base.c
@@ -0,0 +1,152 @@
+/*
+ * Base functions for profiling.
+ *
+ * Copyright IBM Corp. 2008
+ * Author(s): Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
+ *
+ * Uses gcc-internal data definitions.
+ * Based on the gcov-kernel patch by:
+ * Hubertus Franke <frankeh@us.ibm.com>
+ * Nigel Hinds <nhinds@us.ibm.com>
+ * Rajan Ravindran <rajancr@us.ibm.com>
+ * Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
+ * Paul Larson
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/syscalls.h>
+#include "gcov.h"
+
+static gcov_callback_t gcov_callback;
+static struct gcov_info *gcov_info_head;
+static DEFINE_MUTEX(gcov_lock);
+
+static void gcov_register_info(struct gcov_info *info)
+{
+ info->next = gcov_info_head;
+ gcov_info_head = info;
+ if (gcov_callback)
+ gcov_callback(gcov_add, info);
+}
+
+#if GCC_VERSION_LOWER(3, 4)
+
+#error "GCOV profiling support for gcc versions below 3.4 not included"
+
+#else
+/* Functions needed by profiling code for gcc 3.4 and above. */
+
+unsigned int gcov_version;
+
+void __gcov_init(struct gcov_info *info)
+{
+ mutex_lock(&gcov_lock);
+ /* Check for compatible gcc version. */
+ if (gcov_version == 0) {
+ gcov_version = info->version;
+ printk(KERN_INFO TAG "gcc version %x\n", gcov_version);
+ } else if (info->version != gcov_version) {
+ printk(KERN_WARNING TAG "version mismatch in %s\n",
+ info->filename);
+ goto out;
+ }
+ gcov_register_info(info);
+out:
+ mutex_unlock(&gcov_lock);
+}
+EXPORT_SYMBOL(__gcov_init);
+
+/* These functions may be referenced by profiling code but serve no function
+ * for kernel profiling. */
+void __gcov_flush(void)
+{
+ /* Unused. */
+}
+EXPORT_SYMBOL(__gcov_flush);
+
+void __gcov_merge_add(gcov_type *counters, unsigned int n_counters)
+{
+ /* Unused. */
+}
+EXPORT_SYMBOL(__gcov_merge_add);
+
+void __gcov_merge_single(gcov_type *counters, unsigned int n_counters)
+{
+ /* Unused. */
+}
+EXPORT_SYMBOL(__gcov_merge_single);
+
+void __gcov_merge_delta(gcov_type *counters, unsigned int n_counters)
+{
+ /* Unused. */
+}
+EXPORT_SYMBOL(__gcov_merge_delta);
+
+int __gcov_execve(const char *path, char *const argv[], char *const envp[])
+{
+ return kernel_execve(path, argv, envp);
+}
+EXPORT_SYMBOL(__gcov_execve);
+
+#endif /* GCC_VERSION */
+
+int gcov_register_callback(gcov_callback_t callback)
+{
+ struct gcov_info *info;
+ int rc;
+
+ mutex_lock(&gcov_lock);
+ if (gcov_callback) {
+ rc = -EBUSY;
+ goto out;
+ }
+ rc = 0;
+ gcov_callback = callback;
+ /* Perform callback for previously registered entries. */
+ for (info = gcov_info_head; info; info = info->next)
+ gcov_callback(gcov_add, info);
+out:
+ mutex_unlock(&gcov_lock);
+
+ return rc;
+}
+
+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;
+
+ 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) {
+ if (mod == module_address((unsigned long) info)) {
+ if (prev)
+ prev->next = info->next;
+ else
+ gcov_info_head = info->next;
+ if (gcov_callback)
+ gcov_callback(gcov_remove, info);
+ } else
+ prev = info;
+ }
+ mutex_unlock(&gcov_lock);
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block gcov_nb = {
+ .notifier_call = gcov_module_notifier,
+};
+
+static int __init gcov_init(void)
+{
+ return register_module_notifier(&gcov_nb);
+}
+__initcall(gcov_init);
Index: linux-2.6.25/kernel/gcov/gcov.h
===================================================================
--- /dev/null
+++ linux-2.6.25/kernel/gcov/gcov.h
@@ -0,0 +1,101 @@
+/*
+ * Profiling infrastructure declarations.
+ *
+ * Copyright IBM Corp. 2008
+ * Author(s): Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
+ *
+ * Uses gcc-internal data definitions.
+ */
+
+#ifndef GCOV_H
+#define GCOV_H GCOV_H
+
+#include <linux/types.h>
+
+#define TAG "gcov: "
+#define GCC_VERSION_LOWER(major, minor) ((__GNUC__ < major) || \
+ (__GNUC__ == major) && \
+ (__GNUC_MINOR__ < minor))
+#if GCC_VERSION_LOWER(3, 4)
+
+#error "GCOV profiling support for gcc versions below 3.4 not included"
+
+#else
+/* Profiling data types used for gcc 3.4 and above. */
+
+#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)
+#define GCOV_TAG_FOR_COUNTER(count) \
+ (GCOV_TAG_COUNTER_BASE + ((unsigned int) (count) << 17))
+
+#if BITS_PER_LONG >= 64
+typedef long gcov_type;
+#else
+typedef long long gcov_type;
+#endif
+
+struct gcov_fn_info {
+ unsigned int ident;
+ unsigned int checksum;
+ unsigned int n_ctrs[0];
+};
+
+struct gcov_ctr_info {
+ unsigned int num;
+ gcov_type *values;
+ void (*merge)(gcov_type *, unsigned int);
+};
+
+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];
+};
+
+extern unsigned int gcov_version;
+
+#endif /* GCC_VERSION_LOWER */
+
+/* Base interface. */
+enum gcov_action {
+ gcov_add,
+ gcov_remove,
+};
+
+typedef void (*gcov_callback_t)(enum gcov_action, struct gcov_info *);
+
+int gcov_register_callback(gcov_callback_t);
+
+/* Iterator control. */
+struct seq_file;
+
+void *gcov_iter_new(struct gcov_info *);
+void gcov_iter_start(void *);
+int gcov_iter_next(void *);
+int gcov_iter_write(void *, struct seq_file *);
+struct gcov_info *gcov_iter_get_info(void *);
+
+/* gcov_info control. */
+void gcov_info_reset(struct gcov_info *);
+int gcov_info_is_compatible(struct gcov_info *, struct gcov_info *);
+void gcov_info_add(struct gcov_info *, struct gcov_info *);
+struct gcov_info *gcov_info_dup(struct gcov_info *);
+void gcov_info_free(struct gcov_info *);
+
+struct gcov_link_t {
+ enum {
+ obj_tree,
+ src_tree,
+ } dir;
+ const char *ext;
+};
+extern const struct gcov_link_t gcov_link[];
+
+#endif /* GCOV_H */
Index: linux-2.6.25/lib/Kconfig.debug
===================================================================
--- linux-2.6.25.orig/lib/Kconfig.debug
+++ linux-2.6.25/lib/Kconfig.debug
@@ -622,3 +622,4 @@ config PROVIDE_OHCI1394_DMA_INIT
See Documentation/debugging-via-ohci1394.txt for more information.

source "samples/Kconfig"
+source "kernel/gcov/Kconfig"
Index: linux-2.6.25/kernel/Makefile
===================================================================
--- linux-2.6.25.orig/kernel/Makefile
+++ linux-2.6.25/kernel/Makefile
@@ -68,6 +68,7 @@ obj-$(CONFIG_TASK_DELAY_ACCT) += delayac
obj-$(CONFIG_TASKSTATS) += taskstats.o tsacct.o
obj-$(CONFIG_MARKERS) += marker.o
obj-$(CONFIG_LATENCYTOP) += latencytop.o
+obj-$(CONFIG_GCOV_PROFILE) += gcov/

ifneq ($(CONFIG_SCHED_NO_NO_OMIT_FRAME_POINTER),y)
# According to Alan Modra <alan@linuxcare.com.au>, the -fno-omit-frame-pointer is
Index: linux-2.6.25/kernel/gcov/Makefile
===================================================================
--- /dev/null
+++ linux-2.6.25/kernel/gcov/Makefile
@@ -0,0 +1,11 @@
+EXTRA_CFLAGS := -DSRCTREE='"$(srctree)"' -DOBJTREE='"$(objtree)"'
+
+gcc-ver-lower-3.4 := $(call cc-ifversion, -lt, 0304, y)
+
+obj-$(CONFIG_GCOV_PROFILE) := base.o fs.o
+
+ifeq ($(gcc-ver-lower-3.4),y)
+$(error GCOV profiling support for gcc versions below 3.4 not included)
+else
+obj-$(CONFIG_GCOV_PROFILE) += gcc_3_4.o
+endif
Index: linux-2.6.25/kernel/gcov/fs.c
===================================================================
--- /dev/null
+++ linux-2.6.25/kernel/gcov/fs.c
@@ -0,0 +1,542 @@
+/*
+ * Filesystem for exporting profiling data to userspace.
+ *
+ * Copyright IBM Corp. 2008
+ * Author(s): Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
+ *
+ * Uses gcc-internal data definitions.
+ * Based on the gcov-kernel patch by:
+ * Hubertus Franke <frankeh@us.ibm.com>
+ * Nigel Hinds <nhinds@us.ibm.com>
+ * Rajan Ravindran <rajancr@us.ibm.com>
+ * Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
+ * Paul Larson
+ * Yi CDL Yang
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/debugfs.h>
+#include <linux/fs.h>
+#include <linux/list.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/mutex.h>
+#include <linux/seq_file.h>
+#include "gcov.h"
+
+struct node_t {
+ struct list_head list;
+ struct list_head children;
+ struct list_head all;
+ struct node_t *parent;
+ struct gcov_info *info;
+ struct gcov_info *ghost;
+ struct dentry *dentry;
+ struct dentry **links;
+ char name[0];
+};
+
+static const char objtree[] = OBJTREE;
+static const char srctree[] = SRCTREE;
+static struct node_t root_node;
+static struct list_head all_head;
+static struct dentry *reset_dentry;
+static DEFINE_MUTEX(node_lock);
+
+/* If non-zero, keep copies of profiling data for unloaded modules. */
+static int gcov_persist = 1;
+
+static int __init gcov_persist_setup(char *str)
+{
+ int val;
+ char delim;
+
+ if (sscanf(str, "%d %c", &val, &delim) != 1) {
+ printk(KERN_WARNING TAG "invalid gcov_persist parameter '%s'\n",
+ str);
+ return 0;
+ }
+ printk(KERN_INFO TAG "setting gcov_persist to %d\n", val);
+ gcov_persist = val;
+
+ return 1;
+}
+__setup("gcov_persist=", gcov_persist_setup);
+
+static void *gcov_seq_start(struct seq_file *seq, loff_t *pos)
+{
+ loff_t i;
+
+ gcov_iter_start(seq->private);
+ for (i = 0; i < *pos; i++)
+ if (gcov_iter_next(seq->private))
+ return NULL;
+
+ return seq->private;
+}
+
+static void *gcov_seq_next(struct seq_file *seq, void *data, loff_t *pos)
+{
+ struct iterator_t *iter = data;
+
+ if (gcov_iter_next(iter))
+ return NULL;
+ (*pos)++;
+
+ return iter;
+}
+
+static int gcov_seq_show(struct seq_file *seq, void *data)
+{
+ struct iterator_t *iter = data;
+
+ return gcov_iter_write(iter, seq);
+}
+
+static void gcov_seq_stop(struct seq_file *seq, void *data)
+{
+ /* Unused. */
+}
+
+static struct seq_operations seq_ops = {
+ .start = gcov_seq_start,
+ .next = gcov_seq_next,
+ .show = gcov_seq_show,
+ .stop = gcov_seq_stop,
+};
+
+struct gcov_info *get_node_info(struct node_t *node)
+{
+ if (node->info)
+ return node->info;
+
+ return node->ghost;
+}
+
+static int gcov_seq_open(struct inode *inode, struct file *file)
+{
+ struct node_t *node = inode->i_private;
+ struct iterator_t *iter;
+ struct seq_file *seq;
+ struct gcov_info *info;
+ int rc;
+
+ mutex_lock(&node_lock);
+ /* Read from a profiling data copy to minimize reference tracking
+ * complexity and concurrent access. */
+ info = gcov_info_dup(get_node_info(node));
+ if (!info) {
+ rc = -ENOMEM;
+ goto out_unlock;
+ }
+ iter = gcov_iter_new(info);
+ if (!iter) {
+ rc = -ENOMEM;
+ goto out_free;
+ }
+ rc = seq_open(file, &seq_ops);
+ if (rc)
+ goto out_free2;
+ seq = file->private_data;
+ seq->private = iter;
+ goto out_unlock;
+
+out_free2:
+ kfree(iter);
+out_free:
+ kfree(info);
+out_unlock:
+ mutex_unlock(&node_lock);
+
+ return rc;
+}
+
+static int gcov_seq_release(struct inode *inode, struct file *file)
+{
+ struct gcov_info *info;
+ struct seq_file *seq = file->private_data;
+
+ info = gcov_iter_get_info(seq->private);
+ kfree(info);
+ kfree(seq->private);
+ seq_release(inode, file);
+
+ return 0;
+}
+
+static struct node_t *get_node_by_name(const char *name)
+{
+ struct node_t *node;
+ struct gcov_info *info;
+
+ list_for_each_entry(node, &all_head, all) {
+ info = get_node_info(node);
+ if (info && (strcmp(info->filename, name) == 0))
+ return node;
+ }
+
+ return NULL;
+}
+
+static void remove_node(struct node_t *node);
+
+static ssize_t gcov_seq_write(struct file *file, const char __user *addr,
+ size_t len, loff_t *pos)
+{
+ struct seq_file *seq = file->private_data;
+ struct gcov_info *info = gcov_iter_get_info(seq->private);
+ struct node_t *node;
+
+ mutex_lock(&node_lock);
+ node = get_node_by_name(info->filename);
+ if (node) {
+ /* Reset counts or remove node for unloaded modules. */
+ if (node->ghost)
+ remove_node(node);
+ else
+ gcov_info_reset(node->info);
+ }
+ /* Reset counts for open file. */
+ gcov_info_reset(info);
+ mutex_unlock(&node_lock);
+
+ return len;
+}
+
+static char *build_target(const char *dir, const char *rel, const char *ext)
+{
+ char *target;
+ char *old_ext;
+
+ if (dir) {
+ /* DIR + '/' + REL + '.' + EXT + '\0' */
+ target = kmalloc(strlen(dir) + strlen(rel) + strlen(ext) + 3,
+ GFP_KERNEL);
+ if (!target)
+ return NULL;
+ sprintf(target, "%s/%s", dir, rel);
+ } else {
+ /* REL + '.' + EXT + '\0' */
+ target = kmalloc(strlen(rel) + strlen(ext) + 2, GFP_KERNEL);
+ if (!target)
+ return NULL;
+ sprintf(target, "%s", rel);
+ }
+ old_ext = strrchr(target, '.');
+ if (!old_ext)
+ old_ext = target + strlen(target);
+ sprintf(old_ext, ".%s", ext);
+
+ return target;
+}
+
+char *get_link_target(const char *filename, const struct gcov_link_t *ext)
+{
+ const char *rel;
+ char *result;
+
+ if (strncmp(filename, objtree, strlen(objtree)) == 0) {
+ rel = filename + strlen(objtree) + 1;
+ if (ext->dir == src_tree)
+ result = build_target(srctree, rel, ext->ext);
+ else
+ result = build_target(objtree, rel, ext->ext);
+ } else {
+ /* External compilation. */
+ result = build_target(NULL, filename, ext->ext);
+ }
+ return result;
+}
+
+static void add_links(struct node_t *node, struct dentry *parent)
+{
+ char *basename;
+ char *target;
+ int num;
+ int i;
+
+ for (num = 0; gcov_link[num].ext; num++)
+ /* Nothing. */;
+ node->links = kcalloc(num, sizeof(struct dentry *), GFP_KERNEL);
+ if (!node->links)
+ return;
+ for (i = 0; i < num; i++) {
+ target = get_link_target(get_node_info(node)->filename,
+ &gcov_link[i]);
+ if (!target)
+ goto out_err;
+ basename = strrchr(target, '/');
+ if (!basename)
+ goto out_err;
+ basename++;
+ node->links[i] = debugfs_create_symlink(basename, parent,
+ target);
+ if (!node->links[i])
+ goto out_err;
+ kfree(target);
+ }
+
+ return;
+out_err:
+ kfree(target);
+ while (i-- > 0)
+ debugfs_remove(node->links[i]);
+ kfree(node->links);
+ node->links = NULL;
+}
+
+static struct file_operations data_fops = {
+ .open = gcov_seq_open,
+ .release = gcov_seq_release,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .write = gcov_seq_write,
+};
+
+static void init_node(struct node_t *node, struct gcov_info *info,
+ const char *name)
+{
+ INIT_LIST_HEAD(&node->list);
+ INIT_LIST_HEAD(&node->children);
+ INIT_LIST_HEAD(&node->all);
+ node->info = info;
+ if (name)
+ strcpy(node->name, name);
+}
+
+static struct node_t *new_node(struct node_t *parent, struct gcov_info *info,
+ const char *name)
+{
+ struct node_t *node;
+
+ node = kzalloc(sizeof(struct node_t) + strlen(name) + 1, GFP_KERNEL);
+ if (!node) {
+ printk(KERN_WARNING TAG "out of memory\n");
+ return NULL;
+ }
+ init_node(node, info, name);
+ if (info) {
+ node->dentry = debugfs_create_file(node->name, 0600,
+ parent->dentry, node, &data_fops);
+ } else
+ node->dentry = debugfs_create_dir(node->name, parent->dentry);
+ if (!node->dentry) {
+ printk(KERN_WARNING TAG "could not create file\n");
+ kfree(node);
+ return NULL;
+ }
+ if (info)
+ add_links(node, parent->dentry);
+ list_add(&node->list, &parent->children);
+ list_add(&node->all, &all_head);
+
+ return node;
+}
+
+static void remove_links(struct node_t *node)
+{
+ int i;
+
+ if (!node->links)
+ return;
+ for (i = 0; gcov_link[i].ext; i++)
+ debugfs_remove(node->links[i]);
+ kfree(node->links);
+ node->links = NULL;
+}
+
+static void release_node(struct node_t *node)
+{
+ list_del(&node->list);
+ list_del(&node->all);
+ debugfs_remove(node->dentry);
+ remove_links(node);
+ kfree(node->ghost);
+ kfree(node);
+}
+
+static void remove_node(struct node_t *node)
+{
+ struct node_t *parent;
+
+ while ((node != &root_node) && list_empty(&node->children)) {
+ parent = node->parent;
+ release_node(node);
+ node = parent;
+ }
+}
+
+static struct node_t *get_child_by_name(struct node_t *parent, const char *name)
+{
+ struct node_t *node;
+
+ list_for_each_entry(node, &parent->children, list) {
+ if (strcmp(node->name, name) == 0)
+ return node;
+ }
+
+ return NULL;
+}
+
+static ssize_t reset_write(struct file *file, const char __user *addr,
+ size_t len, loff_t *pos)
+{
+ struct node_t *node;
+ struct node_t *r;
+
+ mutex_lock(&node_lock);
+ list_for_each_entry_safe(node, r, &all_head, all) {
+ if (node->info)
+ gcov_info_reset(node->info);
+ else
+ remove_node(node);
+ }
+ mutex_unlock(&node_lock);
+
+ return len;
+}
+
+static ssize_t reset_read(struct file *file, char __user *addr, size_t len,
+ loff_t *pos)
+{
+ /* Allow read operation so that a recursive copy won't fail. */
+ return 0;
+}
+
+static struct file_operations reset_fops = {
+ .write = reset_write,
+ .read = reset_read,
+};
+
+static void add_node(struct gcov_info *info)
+{
+ char *filename;
+ char *curr;
+ char *next;
+ struct node_t *parent;
+ struct node_t *node;
+
+ filename = kstrdup(info->filename, GFP_KERNEL);
+ if (!filename)
+ return;
+ parent = &root_node;
+ /* Create path nodes. */
+ for (curr = filename; (next = strchr(curr, '/')); curr = next + 1) {
+ if (curr == next)
+ continue;
+ *next = 0;
+ node = get_child_by_name(parent, curr);
+ if (!node) {
+ node = new_node(parent, NULL, curr);
+ if (!node)
+ goto out_err;
+ }
+ parent = node;
+ }
+ /* Create file node. */
+ node = new_node(parent, info, curr);
+ if (node)
+ goto out;
+out_err:
+ remove_node(parent);
+out:
+ kfree(filename);
+}
+
+static int ghost_node(struct node_t *node)
+{
+ node->ghost = gcov_info_dup(node->info);
+ if (!node->ghost) {
+ printk(KERN_WARNING TAG "could not save data for '%s' (out of "
+ "memory)\n", node->info->filename);
+ return -ENOMEM;
+ }
+ node->info = NULL;
+
+ return 0;
+}
+
+static void revive_node(struct node_t *node, struct gcov_info *info)
+{
+ if (gcov_info_is_compatible(node->ghost, info))
+ gcov_info_add(info, node->ghost);
+ else {
+ printk(KERN_WARNING TAG "could not add data for '%s' "
+ "(incompatible data)\n", info->filename);
+ }
+ kfree(node->ghost);
+ node->ghost = NULL;
+ node->info = info;
+}
+
+static void gcov_cb(enum gcov_action action, struct gcov_info *info)
+{
+ struct node_t *node;
+
+ mutex_lock(&node_lock);
+ node = get_node_by_name(info->filename);
+ switch (action) {
+ case gcov_add:
+ if (!node) {
+ add_node(info);
+ break;
+ }
+ if (gcov_persist)
+ revive_node(node, info);
+ else
+ printk(KERN_WARNING TAG "could not add '%s' "
+ "(already exists)\n", info->filename);
+ break;
+ case gcov_remove:
+ if (!node) {
+ printk(KERN_WARNING TAG "could not remove '%s' (not "
+ "found)\n", info->filename);
+ break;
+ }
+ if (gcov_persist) {
+ if (!ghost_node(node))
+ break;
+ }
+ remove_node(node);
+ break;
+ }
+ mutex_unlock(&node_lock);
+}
+
+static __init int gcov_fs_init(void)
+{
+ int rc;
+
+ INIT_LIST_HEAD(&all_head);
+ init_node(&root_node, NULL, NULL);
+ root_node.dentry = debugfs_create_dir("gcov", NULL);
+ if (!root_node.dentry) {
+ printk(KERN_WARNING TAG "could not create root dir\n");
+ rc = -EIO;
+ goto out_remove;
+ }
+ reset_dentry = debugfs_create_file("reset", 0600, root_node.dentry,
+ NULL, &reset_fops);
+ if (!reset_dentry) {
+ printk(KERN_WARNING TAG "could not create reset file\n");
+ rc = -EIO;
+ goto out_remove;
+ }
+ rc = gcov_register_callback(gcov_cb);
+ if (rc) {
+ printk(KERN_WARNING TAG "could not register callback (rc=%d)\n",
+ rc);
+ goto out_remove;
+ }
+
+ return 0;
+out_remove:
+ if (reset_dentry)
+ debugfs_remove(reset_dentry);
+ if (root_node.dentry)
+ debugfs_remove(root_node.dentry);
+
+ return rc;
+}
+__initcall(gcov_fs_init);
Index: linux-2.6.25/kernel/gcov/gcc_3_4.c
===================================================================
--- /dev/null
+++ linux-2.6.25/kernel/gcov/gcc_3_4.c
@@ -0,0 +1,374 @@
+/*
+ * Handling of profiling data.
+ *
+ * Copyright IBM Corp. 2008
+ * Author(s): Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
+ *
+ * Uses gcc-internal data definitions.
+ */
+
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/seq_file.h>
+#include "gcov.h"
+
+const struct gcov_link_t gcov_link[] = {
+ { src_tree, "c" },
+ { obj_tree, "gcno" },
+ { 0, NULL},
+};
+
+/* Determine whether counter type is active in info. */
+static int counter_active(struct gcov_info *info, unsigned int type)
+{
+ return (1 << type) & info->ctr_mask;
+}
+
+/* Return the number of active counter types for info. */
+static unsigned int num_counter_active(struct gcov_info *info)
+{
+ unsigned int i;
+ unsigned int result = 0;
+
+ for (i = 0; i < GCOV_COUNTERS; i++)
+ if (counter_active(info, i))
+ result++;
+ return result;
+}
+
+/**
+ * gcov_info_reset - reset profiling data
+ * @info: profiling data address
+ */
+void gcov_info_reset(struct gcov_info *info)
+{
+ struct gcov_ctr_info *ctr = info->counts;
+ unsigned int i;
+
+ for (i = 0; i < GCOV_COUNTERS; i++) {
+ if (counter_active(info, i)) {
+ memset(ctr->values, 0, ctr->num * sizeof(gcov_type));
+ ctr++;
+ }
+ }
+}
+
+/**
+ * gcov_info_is_compatible - return whether profiling data can be added
+ * @info1: address of first profiling data set
+ * @info2: address of second profiling data set
+ *
+ * Returns non-zero if profiling data can be added, zero otherwise.
+ */
+int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2)
+{
+ return (info1->stamp == info2->stamp);
+}
+
+/**
+ * gcov_info_add - add up profiling data
+ * @dest: address of profiling data to which data is added
+ * @source: address of profiling data which is added
+ *
+ * Adds profiling counts of @source to @dest.
+ */
+void gcov_info_add(struct gcov_info *dest, struct gcov_info *source)
+{
+ unsigned int i;
+ unsigned int j;
+
+ for (i = 0; i < num_counter_active(dest); i++)
+ for (j = 0; j < dest->counts[i].num; j++)
+ dest->counts[i].values[j] +=
+ source->counts[i].values[j];
+}
+
+/* Get size of function info entry. */
+static size_t get_fn_size(struct gcov_info *info)
+{
+ size_t size;
+
+ size = sizeof(struct gcov_fn_info) + num_counter_active(info) *
+ sizeof(unsigned int);
+ if (__alignof__(struct gcov_fn_info) > sizeof(unsigned int))
+ size = ALIGN(size, __alignof__(struct gcov_fn_info));
+ return size;
+}
+
+/* Get address of function info entry. */
+static struct gcov_fn_info *get_fn_info(struct gcov_info *info, unsigned int fn)
+{
+ return (struct gcov_fn_info *)
+ ((char *) info->functions + fn * get_fn_size(info));
+}
+
+/**
+ * gcov_info_dup - duplicate profiling data
+ * @info: address of profiling data to duplicate
+ *
+ * Return the address of the newly allocated duplicate on success, %NULL on
+ * error.
+ */
+struct gcov_info *gcov_info_dup(struct gcov_info *info)
+{
+ struct gcov_info *result;
+ size_t len;
+ unsigned int active;
+ unsigned int i;
+ char *name;
+ struct gcov_fn_info *func;
+ gcov_type *values;
+
+ /* Allocate memory for struct gcov_info */
+ active = num_counter_active(info);
+ len = sizeof(struct gcov_info) + sizeof(struct gcov_ctr_info) * active +
+ strlen(info->filename) + 1;
+ for (i = 0; i < active; i++)
+ len += sizeof(gcov_type) * info->counts[i].num;
+ result = kzalloc(len, GFP_KERNEL);
+ if (!result)
+ return NULL;
+ /* Allocate memory for array of struct gcov_fn_info */
+ len = info->n_functions * get_fn_size(info);
+ func = kmalloc(len, GFP_KERNEL);
+ if (!func) {
+ kfree(result);
+ return NULL;
+ }
+ /* Copy function data */
+ memcpy(func, info->functions, len);
+ result->functions = func;
+ /* Copy counts */
+ values = (gcov_type *) &result->counts[active];
+ for (i = 0; i < active; i++) {
+ result->counts[i].num = info->counts[i].num;
+ result->counts[i].merge = info->counts[i].merge;
+ result->counts[i].values = values;
+ memcpy(values, info->counts[i].values,
+ sizeof(gcov_type) * info->counts[i].num);
+ values += info->counts[i].num;
+ }
+ /* Copy rest */
+ result->stamp = info->stamp;
+ name = (char *) values;
+ strcpy(name, info->filename);
+ result->filename = name;
+ result->n_functions = info->n_functions;
+ result->ctr_mask = info->ctr_mask;
+
+ return result;
+}
+
+/**
+ * gcov_info_free - release memory for profiling data duplicate
+ * @info: address of profiling data to free
+ */
+void gcov_info_free(struct gcov_info *info)
+{
+ kfree(info->functions);
+ kfree(info);
+}
+
+struct type_info {
+ int num;
+ unsigned int offset;
+};
+
+struct iterator_t {
+ struct gcov_info *info;
+
+ int record;
+ unsigned int function;
+ unsigned int type;
+ unsigned int count;
+
+ int num_types;
+ struct type_info type_info[0];
+};
+
+static struct gcov_fn_info *get_func(struct iterator_t *iter)
+{
+ return get_fn_info(iter->info, iter->function);
+}
+
+static struct type_info *get_type(struct iterator_t *iter)
+{
+ return &iter->type_info[iter->type];
+}
+
+/**
+ * gcov_iter_new - allocate and initialize profiling data iterator
+ * @info: address of profiling data to be iterated
+ *
+ * Return address of iterator on success, %NULL otherwise.
+ */
+void *gcov_iter_new(struct gcov_info *info)
+{
+ struct iterator_t *iter;
+
+ iter = kzalloc(sizeof(struct iterator_t) +
+ num_counter_active(info) * sizeof(struct type_info),
+ GFP_KERNEL);
+ if (iter)
+ iter->info = info;
+
+ return iter;
+}
+
+/**
+ * gcov_iter_get_info - return address of profiling data for iterator
+ * @data: iterator address
+ */
+struct gcov_info *gcov_iter_get_info(void *data)
+{
+ struct iterator_t *iter = data;
+
+ return iter->info;
+}
+
+/**
+ * gcov_iter_start - reset iterator to starting position
+ * @data: iterator address
+ */
+void gcov_iter_start(void *data)
+{
+ struct iterator_t *iter = data;
+ int i;
+
+ iter->record = 0;
+ iter->function = 0;
+ iter->type = 0;
+ iter->count = 0;
+ iter->num_types = 0;
+ for (i = 0; i < GCOV_COUNTERS; i++) {
+ if (counter_active(iter->info, i)) {
+ iter->type_info[iter->num_types].num = i;
+ iter->type_info[iter->num_types++].offset = 0;
+ }
+ }
+}
+
+/**
+ * gcov_iter_next - advance iterator to next pos
+ * @data: iterator address
+ *
+ * Return zero if new position is valid, non-zero if iterator has reached end.
+ */
+int gcov_iter_next(void *data)
+{
+ struct iterator_t *iter = data;
+
+ switch (iter->record) {
+ case 0:
+ case 1:
+ case 3:
+ case 4:
+ case 5:
+ case 7:
+ /* Advance to next record */
+ iter->record++;
+ break;
+ case 9:
+ /* Advance to next count */
+ iter->count++;
+ /* fall through */
+ case 8:
+ if (iter->count < get_func(iter)->n_ctrs[iter->type]) {
+ iter->record = 9;
+ break;
+ }
+ /* Advance to next counter type */
+ get_type(iter)->offset += iter->count;
+ iter->count = 0;
+ iter->type++;
+ /* fall through */
+ case 6:
+ if (iter->type < iter->num_types) {
+ iter->record = 7;
+ break;
+ }
+ /* Advance to next function */
+ iter->type = 0;
+ iter->function++;
+ /* fall through */
+ case 2:
+ if (iter->function < iter->info->n_functions)
+ iter->record = 3;
+ else
+ iter->record = -1;
+ break;
+ }
+ /* Check for EOF. */
+ if (iter->record == -1)
+ return -EINVAL;
+ else
+ return 0;
+}
+
+static int seq_write_gcov_int(struct seq_file *seq, size_t size, u64 v)
+{
+ u32 data[2];
+
+ switch (size) {
+ case 8:
+ data[1] = (u32) (v >> 32);
+ /* fall through */
+ case 4:
+ data[0] = (u32) (v & 0xffffffffUL);
+ return seq_write(seq, data, size);
+ }
+ return -EINVAL;
+}
+
+/**
+ * gcov_iter_write - write data for current pos to seq_file
+ * @data: iterator address
+ * @seq: seq_file address
+ *
+ * Return zero on success, non-zero otherwise.
+ */
+int gcov_iter_write(void *data, struct seq_file *seq)
+{
+ struct iterator_t *iter = data;
+ int rc;
+
+ rc = -EINVAL;
+ switch (iter->record) {
+ case 0: /* file magic */
+ rc = seq_write_gcov_int(seq, 4, GCOV_DATA_MAGIC);
+ break;
+ case 1: /* gcov_version */
+ rc = seq_write_gcov_int(seq, 4, gcov_version);
+ break;
+ case 2: /* time stamp */
+ rc = seq_write_gcov_int(seq, 4, iter->info->stamp);
+ break;
+ case 3: /* function tag */
+ rc = seq_write_gcov_int(seq, 4, GCOV_TAG_FUNCTION);
+ break;
+ case 4: /* function tag length */
+ rc = seq_write_gcov_int(seq, 4, 2);
+ break;
+ case 5: /* function ident*/
+ rc = seq_write_gcov_int(seq, 4, get_func(iter)->ident);
+ break;
+ case 6: /* function checksum */
+ rc = seq_write_gcov_int(seq, 4, get_func(iter)->checksum);
+ break;
+ case 7: /* count tag */
+ rc = seq_write_gcov_int(seq, 4,
+ GCOV_TAG_FOR_COUNTER(get_type(iter)->num));
+ break;
+ case 8: /* count length */
+ rc = seq_write_gcov_int(seq, 4,
+ get_func(iter)->n_ctrs[iter->type] * 2);
+ break;
+ case 9: /* count */
+ rc = seq_write_gcov_int(seq, 8,
+ iter->info->counts[iter->type].
+ values[iter->count + get_type(iter)->offset]);
+ break;
+ }
+ return rc;
+}





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