Resguardo inicial

linux-7.2.3/kernel/gcov/Kconfig

@@ -0,0 +1,55 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menu "GCOV-based kernel profiling"
+
+config GCOV_KERNEL
+	bool "Enable gcov-based kernel profiling"
+	depends on DEBUG_FS
+	depends on !ARCH_WANTS_NO_INSTR || CC_HAS_NO_PROFILE_FN_ATTR
+	select CONSTRUCTORS
+	default n
+	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_PROFILE_main.o := y
+
+	For all files in one directory:
+	        GCOV_PROFILE := y
+
+	To exclude files from being profiled even when CONFIG_GCOV_PROFILE_ALL
+	is specified, use:
+
+	        GCOV_PROFILE_main.o := n
+	and:
+	        GCOV_PROFILE := n
+
+	Note that the debugfs filesystem has to be mounted to access
+	profiling data.
+
+config ARCH_HAS_GCOV_PROFILE_ALL
+	def_bool n
+
+config GCOV_PROFILE_ALL
+	bool "Profile entire Kernel"
+	depends on !COMPILE_TEST
+	depends on GCOV_KERNEL
+	depends on ARCH_HAS_GCOV_PROFILE_ALL
+	default n
+	help
+	This options activates profiling for the entire kernel.
+
+	If unsure, say N.
+
+	Note that a kernel compiled with profiling flags will be significantly
+	larger and run slower. Also be sure to exclude files from profiling
+	which are not linked to the kernel image to prevent linker errors.
+
+endmenu

linux-7.2.3/kernel/gcov/Makefile

@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: GPL-2.0
+ccflags-y := -DSRCTREE='"$(srctree)"' -DOBJTREE='"$(objtree)"'
+
+obj-y := base.o fs.o
+obj-$(CONFIG_CC_IS_GCC) += gcc_base.o gcc_4_7.o
+CFLAGS_gcc_base.o += -Wno-missing-prototypes -Wno-missing-declarations
+obj-$(CONFIG_CC_IS_CLANG) += clang.o
+CFLAGS_clang.o += -Wno-missing-prototypes -Wno-missing-declarations

linux-7.2.3/kernel/gcov/base.c

@@ -0,0 +1,138 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  This code maintains a list of active profiling data structures.
+ *
+ *    Copyright IBM Corp. 2009
+ *    Author(s): Peter Oberparleiter <oberpar@linux.vnet.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 <oberpar@linux.vnet.ibm.com>
+ *		 Paul Larson
+ */
+
+#define pr_fmt(fmt)	"gcov: " fmt
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include "gcov.h"
+
+int gcov_events_enabled;
+DEFINE_MUTEX(gcov_lock);
+
+/**
+ * gcov_enable_events - enable event reporting through gcov_event()
+ *
+ * Turn on reporting of profiling data load/unload-events through the
+ * gcov_event() callback. Also replay all previous events once. This function
+ * is needed because some events are potentially generated too early for the
+ * callback implementation to handle them initially.
+ */
+void gcov_enable_events(void)
+{
+	struct gcov_info *info = NULL;
+
+	mutex_lock(&gcov_lock);
+	gcov_events_enabled = 1;
+
+	/* Perform event callback for previously registered entries. */
+	while ((info = gcov_info_next(info))) {
+		gcov_event(GCOV_ADD, info);
+		cond_resched();
+	}
+
+	mutex_unlock(&gcov_lock);
+}
+
+/**
+ * store_gcov_u32 - store 32 bit number in gcov format to buffer
+ * @buffer: target buffer or NULL
+ * @off: offset into the buffer
+ * @v: value to be stored
+ *
+ * Number format defined by gcc: numbers are recorded in the 32 bit
+ * unsigned binary form of the endianness of the machine generating the
+ * file. Returns the number of bytes stored. If @buffer is %NULL, doesn't
+ * store anything.
+ */
+size_t store_gcov_u32(void *buffer, size_t off, u32 v)
+{
+	u32 *data;
+
+	if (buffer) {
+		data = buffer + off;
+		*data = v;
+	}
+
+	return sizeof(*data);
+}
+
+/**
+ * store_gcov_u64 - store 64 bit number in gcov format to buffer
+ * @buffer: target buffer or NULL
+ * @off: offset into the buffer
+ * @v: value to be stored
+ *
+ * Number format defined by gcc: numbers are recorded in the 32 bit
+ * unsigned binary form of the endianness of the machine generating the
+ * file. 64 bit numbers are stored as two 32 bit numbers, the low part
+ * first. Returns the number of bytes stored. If @buffer is %NULL, doesn't store
+ * anything.
+ */
+size_t store_gcov_u64(void *buffer, size_t off, u64 v)
+{
+	u32 *data;
+
+	if (buffer) {
+		data = buffer + off;
+
+		data[0] = (v & 0xffffffffUL);
+		data[1] = (v >> 32);
+	}
+
+	return sizeof(*data) * 2;
+}
+
+#ifdef CONFIG_MODULES
+/* Update list and generate events when modules are unloaded. */
+static int gcov_module_notifier(struct notifier_block *nb, unsigned long event,
+				void *data)
+{
+	struct module *mod = data;
+	struct gcov_info *info = NULL;
+	struct gcov_info *prev = NULL;
+
+	if (event != MODULE_STATE_GOING)
+		return NOTIFY_OK;
+	mutex_lock(&gcov_lock);
+
+	/* Remove entries located in module from linked list. */
+	while ((info = gcov_info_next(info))) {
+		if (gcov_info_within_module(info, mod)) {
+			gcov_info_unlink(prev, info);
+			if (gcov_events_enabled)
+				gcov_event(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);
+}
+device_initcall(gcov_init);
+#endif /* CONFIG_MODULES */

linux-7.2.3/kernel/gcov/clang.c

@@ -0,0 +1,393 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Google, Inc.
+ * modified from kernel/gcov/gcc_4_7.c
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ *
+ *
+ * LLVM uses profiling data that's deliberately similar to GCC, but has a
+ * very different way of exporting that data.  LLVM calls llvm_gcov_init() once
+ * per module, and provides a couple of callbacks that we can use to ask for
+ * more data.
+ *
+ * We care about the "writeout" callback, which in turn calls back into
+ * compiler-rt/this module to dump all the gathered coverage data to disk:
+ *
+ *    llvm_gcda_start_file()
+ *      llvm_gcda_emit_function()
+ *      llvm_gcda_emit_arcs()
+ *      llvm_gcda_emit_function()
+ *      llvm_gcda_emit_arcs()
+ *      [... repeats for each function ...]
+ *    llvm_gcda_summary_info()
+ *    llvm_gcda_end_file()
+ *
+ * This design is much more stateless and unstructured than gcc's, and is
+ * intended to run at process exit.  This forces us to keep some local state
+ * about which module we're dealing with at the moment.  On the other hand, it
+ * also means we don't depend as much on how LLVM represents profiling data
+ * internally.
+ *
+ * See LLVM's lib/Transforms/Instrumentation/GCOVProfiling.cpp for more
+ * details on how this works, particularly GCOVProfiler::emitProfileArcs(),
+ * GCOVProfiler::insertCounterWriteout(), and
+ * GCOVProfiler::insertFlush().
+ */
+
+#define pr_fmt(fmt)	"gcov: " fmt
+
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/printk.h>
+#include <linux/ratelimit.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include "gcov.h"
+
+typedef void (*llvm_gcov_callback)(void);
+
+struct gcov_info {
+	struct list_head head;
+
+	const char *filename;
+	unsigned int version;
+	u32 checksum;
+
+	struct list_head functions;
+};
+
+struct gcov_fn_info {
+	struct list_head head;
+
+	u32 ident;
+	u32 checksum;
+	u32 cfg_checksum;
+
+	u32 num_counters;
+	u64 *counters;
+};
+
+static struct gcov_info *current_info;
+
+static LIST_HEAD(clang_gcov_list);
+
+void llvm_gcov_init(llvm_gcov_callback writeout, llvm_gcov_callback flush)
+{
+	struct gcov_info *info = kzalloc_obj(*info);
+
+	if (!info)
+		return;
+
+	INIT_LIST_HEAD(&info->head);
+	INIT_LIST_HEAD(&info->functions);
+
+	mutex_lock(&gcov_lock);
+
+	list_add_tail(&info->head, &clang_gcov_list);
+	current_info = info;
+	writeout();
+	current_info = NULL;
+	if (gcov_events_enabled)
+		gcov_event(GCOV_ADD, info);
+
+	mutex_unlock(&gcov_lock);
+}
+EXPORT_SYMBOL(llvm_gcov_init);
+
+void llvm_gcda_start_file(const char *orig_filename, u32 version, u32 checksum)
+{
+	current_info->filename = orig_filename;
+	current_info->version = version;
+	current_info->checksum = checksum;
+}
+EXPORT_SYMBOL(llvm_gcda_start_file);
+
+void llvm_gcda_emit_function(u32 ident, u32 func_checksum, u32 cfg_checksum)
+{
+	struct gcov_fn_info *info = kzalloc_obj(*info);
+
+	if (!info)
+		return;
+
+	INIT_LIST_HEAD(&info->head);
+	info->ident = ident;
+	info->checksum = func_checksum;
+	info->cfg_checksum = cfg_checksum;
+	list_add_tail(&info->head, &current_info->functions);
+}
+EXPORT_SYMBOL(llvm_gcda_emit_function);
+
+void llvm_gcda_emit_arcs(u32 num_counters, u64 *counters)
+{
+	struct gcov_fn_info *info = list_last_entry(&current_info->functions,
+			struct gcov_fn_info, head);
+
+	info->num_counters = num_counters;
+	info->counters = counters;
+}
+EXPORT_SYMBOL(llvm_gcda_emit_arcs);
+
+void llvm_gcda_summary_info(void)
+{
+}
+EXPORT_SYMBOL(llvm_gcda_summary_info);
+
+void llvm_gcda_end_file(void)
+{
+}
+EXPORT_SYMBOL(llvm_gcda_end_file);
+
+/**
+ * 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 list_first_entry_or_null(&clang_gcov_list,
+				struct gcov_info, head);
+	if (list_is_last(&info->head, &clang_gcov_list))
+		return NULL;
+	return list_next_entry(info, head);
+}
+
+/**
+ * gcov_info_link - link/add profiling data set to the list
+ * @info: profiling data set
+ */
+void gcov_info_link(struct gcov_info *info)
+{
+	list_add_tail(&info->head, &clang_gcov_list);
+}
+
+/**
+ * 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)
+{
+	/* Generic code unlinks while iterating. */
+	__list_del_entry(&info->head);
+}
+
+/**
+ * gcov_info_within_module - check if a profiling data set belongs to a module
+ * @info: profiling data set
+ * @mod: module
+ *
+ * Returns true if profiling data belongs module, false otherwise.
+ */
+bool gcov_info_within_module(struct gcov_info *info, struct module *mod)
+{
+	return within_module((unsigned long)info->filename, mod);
+}
+
+/* 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). */
+	{ 0, NULL},
+};
+
+/**
+ * gcov_info_reset - reset profiling data to zero
+ * @info: profiling data set
+ */
+void gcov_info_reset(struct gcov_info *info)
+{
+	struct gcov_fn_info *fn;
+
+	list_for_each_entry(fn, &info->functions, head)
+		memset(fn->counters, 0,
+				sizeof(fn->counters[0]) * fn->num_counters);
+}
+
+/**
+ * gcov_info_is_compatible - check if profiling data can be added
+ * @info1: first profiling data set
+ * @info2: 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)
+{
+	struct gcov_fn_info *fn_ptr1 = list_first_entry_or_null(
+			&info1->functions, struct gcov_fn_info, head);
+	struct gcov_fn_info *fn_ptr2 = list_first_entry_or_null(
+			&info2->functions, struct gcov_fn_info, head);
+
+	if (info1->checksum != info2->checksum)
+		return false;
+	if (!fn_ptr1)
+		return fn_ptr1 == fn_ptr2;
+	while (!list_is_last(&fn_ptr1->head, &info1->functions) &&
+		!list_is_last(&fn_ptr2->head, &info2->functions)) {
+		if (fn_ptr1->checksum != fn_ptr2->checksum)
+			return false;
+		if (fn_ptr1->cfg_checksum != fn_ptr2->cfg_checksum)
+			return false;
+		fn_ptr1 = list_next_entry(fn_ptr1, head);
+		fn_ptr2 = list_next_entry(fn_ptr2, head);
+	}
+	return list_is_last(&fn_ptr1->head, &info1->functions) &&
+		list_is_last(&fn_ptr2->head, &info2->functions);
+}
+
+/**
+ * gcov_info_add - add up profiling data
+ * @dst: profiling data set to which data is added
+ * @src: profiling data set which is added
+ *
+ * Adds profiling counts of @src to @dst.
+ */
+void gcov_info_add(struct gcov_info *dst, struct gcov_info *src)
+{
+	struct gcov_fn_info *dfn_ptr;
+	struct gcov_fn_info *sfn_ptr = list_first_entry_or_null(&src->functions,
+			struct gcov_fn_info, head);
+
+	list_for_each_entry(dfn_ptr, &dst->functions, head) {
+		u32 i;
+
+		for (i = 0; i < sfn_ptr->num_counters; i++)
+			dfn_ptr->counters[i] += sfn_ptr->counters[i];
+
+		sfn_ptr = list_next_entry(sfn_ptr, head);
+	}
+}
+
+static struct gcov_fn_info *gcov_fn_info_dup(struct gcov_fn_info *fn)
+{
+	size_t cv_size; /* counter values size */
+	struct gcov_fn_info *fn_dup = kmemdup(fn, sizeof(*fn),
+			GFP_KERNEL);
+	if (!fn_dup)
+		return NULL;
+	INIT_LIST_HEAD(&fn_dup->head);
+
+	cv_size = fn->num_counters * sizeof(fn->counters[0]);
+	fn_dup->counters = kvmalloc(cv_size, GFP_KERNEL);
+	if (!fn_dup->counters) {
+		kfree(fn_dup);
+		return NULL;
+	}
+
+	memcpy(fn_dup->counters, fn->counters, cv_size);
+
+	return fn_dup;
+}
+
+/**
+ * gcov_info_dup - duplicate profiling data set
+ * @info: profiling data set to duplicate
+ *
+ * Return newly allocated duplicate on success, %NULL on error.
+ */
+struct gcov_info *gcov_info_dup(struct gcov_info *info)
+{
+	struct gcov_info *dup;
+	struct gcov_fn_info *fn;
+
+	dup = kmemdup(info, sizeof(*dup), GFP_KERNEL);
+	if (!dup)
+		return NULL;
+	INIT_LIST_HEAD(&dup->head);
+	INIT_LIST_HEAD(&dup->functions);
+	dup->filename = kstrdup(info->filename, GFP_KERNEL);
+	if (!dup->filename)
+		goto err;
+
+	list_for_each_entry(fn, &info->functions, head) {
+		struct gcov_fn_info *fn_dup = gcov_fn_info_dup(fn);
+
+		if (!fn_dup)
+			goto err;
+		list_add_tail(&fn_dup->head, &dup->functions);
+	}
+
+	return dup;
+
+err:
+	gcov_info_free(dup);
+	return NULL;
+}
+
+/**
+ * gcov_info_free - release memory for profiling data set duplicate
+ * @info: profiling data set duplicate to free
+ */
+void gcov_info_free(struct gcov_info *info)
+{
+	struct gcov_fn_info *fn, *tmp;
+
+	list_for_each_entry_safe(fn, tmp, &info->functions, head) {
+		kvfree(fn->counters);
+		list_del(&fn->head);
+		kfree(fn);
+	}
+	kfree(info->filename);
+	kfree(info);
+}
+
+/**
+ * convert_to_gcda - convert profiling data set to gcda file format
+ * @buffer: the buffer to store file data or %NULL if no data should be stored
+ * @info: profiling data set to be converted
+ *
+ * Returns the number of bytes that were/would have been stored into the buffer.
+ */
+size_t convert_to_gcda(char *buffer, struct gcov_info *info)
+{
+	struct gcov_fn_info *fi_ptr;
+	size_t pos = 0;
+
+	/* File header. */
+	pos += store_gcov_u32(buffer, pos, GCOV_DATA_MAGIC);
+	pos += store_gcov_u32(buffer, pos, info->version);
+	pos += store_gcov_u32(buffer, pos, info->checksum);
+
+	list_for_each_entry(fi_ptr, &info->functions, head) {
+		u32 i;
+
+		pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION);
+		pos += store_gcov_u32(buffer, pos, 3);
+		pos += store_gcov_u32(buffer, pos, fi_ptr->ident);
+		pos += store_gcov_u32(buffer, pos, fi_ptr->checksum);
+		pos += store_gcov_u32(buffer, pos, fi_ptr->cfg_checksum);
+		pos += store_gcov_u32(buffer, pos, GCOV_TAG_COUNTER_BASE);
+		pos += store_gcov_u32(buffer, pos, fi_ptr->num_counters * 2);
+		for (i = 0; i < fi_ptr->num_counters; i++)
+			pos += store_gcov_u64(buffer, pos, fi_ptr->counters[i]);
+	}
+
+	return pos;
+}

linux-7.2.3/kernel/gcov/fs.c

@@ -0,0 +1,881 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  This code exports profiling data as debugfs files to userspace.
+ *
+ *    Copyright IBM Corp. 2009
+ *    Author(s): Peter Oberparleiter <oberpar@linux.vnet.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 <oberpar@linux.vnet.ibm.com>
+ *		 Paul Larson
+ *		 Yi CDL Yang
+ */
+
+#define pr_fmt(fmt)	"gcov: " fmt
+
+#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 <linux/mm.h>
+#include "gcov.h"
+
+/**
+ * struct gcov_node - represents a debugfs entry
+ * @list: list head for child node list
+ * @children: child nodes
+ * @all: list head for list of all nodes
+ * @parent: parent node
+ * @loaded_info: array of pointers to profiling data sets for loaded object
+ *   files.
+ * @num_loaded: number of profiling data sets for loaded object files.
+ * @unloaded_info: accumulated copy of profiling data sets for unloaded
+ *   object files. Used only when gcov_persist=1.
+ * @dentry: main debugfs entry, either a directory or data file
+ * @links: associated symbolic links
+ * @name: data file basename
+ *
+ * struct gcov_node represents an entity within the gcov/ subdirectory
+ * of debugfs. There are directory and data file nodes. The latter represent
+ * the actual synthesized data file plus any associated symbolic links which
+ * are needed by the gcov tool to work correctly.
+ */
+struct gcov_node {
+	struct list_head list;
+	struct list_head children;
+	struct list_head all;
+	struct gcov_node *parent;
+	struct gcov_info **loaded_info;
+	struct gcov_info *unloaded_info;
+	struct dentry *dentry;
+	struct dentry **links;
+	int num_loaded;
+	char name[];
+};
+
+static const char objtree[] = OBJTREE;
+static const char srctree[] = SRCTREE;
+static struct gcov_node root_node;
+static LIST_HEAD(all_head);
+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)
+{
+	unsigned long val;
+
+	if (kstrtoul(str, 0, &val)) {
+		pr_warn("invalid gcov_persist parameter '%s'\n", str);
+		return 0;
+	}
+	gcov_persist = val;
+	pr_info("setting gcov_persist to %d\n", gcov_persist);
+
+	return 1;
+}
+__setup("gcov_persist=", gcov_persist_setup);
+
+#define ITER_STRIDE	PAGE_SIZE
+
+/**
+ * struct gcov_iterator - specifies current file position in logical records
+ * @info: associated profiling data
+ * @buffer: buffer containing file data
+ * @size: size of buffer
+ * @pos: current position in file
+ */
+struct gcov_iterator {
+	struct gcov_info *info;
+	size_t size;
+	loff_t pos;
+	char buffer[] __counted_by(size);
+};
+
+/**
+ * gcov_iter_new - allocate and initialize profiling data iterator
+ * @info: profiling data set to be iterated
+ *
+ * Return file iterator on success, %NULL otherwise.
+ */
+static struct gcov_iterator *gcov_iter_new(struct gcov_info *info)
+{
+	struct gcov_iterator *iter;
+	size_t size;
+
+	/* Dry-run to get the actual buffer size. */
+	size = convert_to_gcda(NULL, info);
+
+	iter = kvmalloc_flex(*iter, buffer, size);
+	if (!iter)
+		return NULL;
+
+	iter->info = info;
+	iter->size = size;
+	convert_to_gcda(iter->buffer, info);
+
+	return iter;
+}
+
+
+/**
+ * gcov_iter_free - free iterator data
+ * @iter: file iterator
+ */
+static void gcov_iter_free(struct gcov_iterator *iter)
+{
+	kvfree(iter);
+}
+
+/**
+ * gcov_iter_get_info - return profiling data set for given file iterator
+ * @iter: file iterator
+ */
+static struct gcov_info *gcov_iter_get_info(struct gcov_iterator *iter)
+{
+	return iter->info;
+}
+
+/**
+ * gcov_iter_start - reset file iterator to starting position
+ * @iter: file iterator
+ */
+static void gcov_iter_start(struct gcov_iterator *iter)
+{
+	iter->pos = 0;
+}
+
+/**
+ * gcov_iter_next - advance file iterator to next logical record
+ * @iter: file iterator
+ *
+ * Return zero if new position is valid, non-zero if iterator has reached end.
+ */
+static int gcov_iter_next(struct gcov_iterator *iter)
+{
+	if (iter->pos < iter->size)
+		iter->pos += ITER_STRIDE;
+
+	if (iter->pos >= iter->size)
+		return -EINVAL;
+
+	return 0;
+}
+
+/**
+ * gcov_iter_write - write data for current pos to seq_file
+ * @iter: file iterator
+ * @seq: seq_file handle
+ *
+ * Return zero on success, non-zero otherwise.
+ */
+static int gcov_iter_write(struct gcov_iterator *iter, struct seq_file *seq)
+{
+	size_t len;
+
+	if (iter->pos >= iter->size)
+		return -EINVAL;
+
+	len = ITER_STRIDE;
+	if (iter->pos + len > iter->size)
+		len = iter->size - iter->pos;
+
+	seq_write(seq, iter->buffer + iter->pos, len);
+
+	return 0;
+}
+
+/*
+ * seq_file.start() implementation for gcov data files. Note that the
+ * gcov_iterator interface is designed to be more restrictive than seq_file
+ * (no start from arbitrary position, etc.), to simplify the iterator
+ * implementation.
+ */
+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;
+}
+
+/* seq_file.next() implementation for gcov data files. */
+static void *gcov_seq_next(struct seq_file *seq, void *data, loff_t *pos)
+{
+	struct gcov_iterator *iter = data;
+
+	(*pos)++;
+	if (gcov_iter_next(iter))
+		return NULL;
+
+	return iter;
+}
+
+/* seq_file.show() implementation for gcov data files. */
+static int gcov_seq_show(struct seq_file *seq, void *data)
+{
+	struct gcov_iterator *iter = data;
+
+	if (gcov_iter_write(iter, seq))
+		return -EINVAL;
+	return 0;
+}
+
+static void gcov_seq_stop(struct seq_file *seq, void *data)
+{
+	/* Unused. */
+}
+
+static const struct seq_operations gcov_seq_ops = {
+	.start	= gcov_seq_start,
+	.next	= gcov_seq_next,
+	.show	= gcov_seq_show,
+	.stop	= gcov_seq_stop,
+};
+
+/*
+ * Return a profiling data set associated with the given node. This is
+ * either a data set for a loaded object file or a data set copy in case
+ * all associated object files have been unloaded.
+ */
+static struct gcov_info *get_node_info(struct gcov_node *node)
+{
+	if (node->num_loaded > 0)
+		return node->loaded_info[0];
+
+	return node->unloaded_info;
+}
+
+/*
+ * Return a newly allocated profiling data set which contains the sum of
+ * all profiling data associated with the given node.
+ */
+static struct gcov_info *get_accumulated_info(struct gcov_node *node)
+{
+	struct gcov_info *info;
+	int i = 0;
+
+	if (node->unloaded_info)
+		info = gcov_info_dup(node->unloaded_info);
+	else
+		info = gcov_info_dup(node->loaded_info[i++]);
+	if (!info)
+		return NULL;
+	for (; i < node->num_loaded; i++)
+		gcov_info_add(info, node->loaded_info[i]);
+
+	return info;
+}
+
+/*
+ * open() implementation for gcov data files. Create a copy of the profiling
+ * data set and initialize the iterator and seq_file interface.
+ */
+static int gcov_seq_open(struct inode *inode, struct file *file)
+{
+	struct gcov_node *node = inode->i_private;
+	struct gcov_iterator *iter;
+	struct seq_file *seq;
+	struct gcov_info *info;
+	int rc = -ENOMEM;
+
+	mutex_lock(&node_lock);
+	/*
+	 * Read from a profiling data copy to minimize reference tracking
+	 * complexity and concurrent access and to keep accumulating multiple
+	 * profiling data sets associated with one node simple.
+	 */
+	info = get_accumulated_info(node);
+	if (!info)
+		goto out_unlock;
+	iter = gcov_iter_new(info);
+	if (!iter)
+		goto err_free_info;
+	rc = seq_open(file, &gcov_seq_ops);
+	if (rc)
+		goto err_free_iter_info;
+	seq = file->private_data;
+	seq->private = iter;
+out_unlock:
+	mutex_unlock(&node_lock);
+	return rc;
+
+err_free_iter_info:
+	gcov_iter_free(iter);
+err_free_info:
+	gcov_info_free(info);
+	goto out_unlock;
+}
+
+/*
+ * release() implementation for gcov data files. Release resources allocated
+ * by open().
+ */
+static int gcov_seq_release(struct inode *inode, struct file *file)
+{
+	struct gcov_iterator *iter;
+	struct gcov_info *info;
+	struct seq_file *seq;
+
+	seq = file->private_data;
+	iter = seq->private;
+	info = gcov_iter_get_info(iter);
+	gcov_iter_free(iter);
+	gcov_info_free(info);
+	seq_release(inode, file);
+
+	return 0;
+}
+
+/*
+ * Find a node by the associated data file name. Needs to be called with
+ * node_lock held.
+ */
+static struct gcov_node *get_node_by_name(const char *name)
+{
+	struct gcov_node *node;
+	struct gcov_info *info;
+
+	list_for_each_entry(node, &all_head, all) {
+		info = get_node_info(node);
+		if (info && (strcmp(gcov_info_filename(info), name) == 0))
+			return node;
+	}
+
+	return NULL;
+}
+
+/*
+ * Reset all profiling data associated with the specified node.
+ */
+static void reset_node(struct gcov_node *node)
+{
+	int i;
+
+	if (node->unloaded_info)
+		gcov_info_reset(node->unloaded_info);
+	for (i = 0; i < node->num_loaded; i++)
+		gcov_info_reset(node->loaded_info[i]);
+}
+
+static void remove_node(struct gcov_node *node);
+
+/*
+ * write() implementation for gcov data files. Reset profiling data for the
+ * corresponding file. If all associated object files have been unloaded,
+ * remove the debug fs node as well.
+ */
+static ssize_t gcov_seq_write(struct file *file, const char __user *addr,
+			      size_t len, loff_t *pos)
+{
+	struct seq_file *seq;
+	struct gcov_info *info;
+	struct gcov_node *node;
+
+	seq = file->private_data;
+	info = gcov_iter_get_info(seq->private);
+	mutex_lock(&node_lock);
+	node = get_node_by_name(gcov_info_filename(info));
+	if (node) {
+		/* Reset counts or remove node for unloaded modules. */
+		if (node->num_loaded == 0)
+			remove_node(node);
+		else
+			reset_node(node);
+	}
+	/* Reset counts for open file. */
+	gcov_info_reset(info);
+	mutex_unlock(&node_lock);
+
+	return len;
+}
+
+/*
+ * Given a string <path> representing a file path of format:
+ *   path/to/file.gcda
+ * construct and return a new string:
+ *   <dir/>path/to/file.<ext>
+ */
+static char *link_target(const char *dir, const char *path, const char *ext)
+{
+	char *target;
+	char *old_ext;
+	char *copy;
+
+	copy = kstrdup(path, GFP_KERNEL);
+	if (!copy)
+		return NULL;
+	old_ext = strrchr(copy, '.');
+	if (old_ext)
+		*old_ext = '\0';
+	if (dir)
+		target = kasprintf(GFP_KERNEL, "%s/%s.%s", dir, copy, ext);
+	else
+		target = kasprintf(GFP_KERNEL, "%s.%s", copy, ext);
+	kfree(copy);
+
+	return target;
+}
+
+/*
+ * Construct a string representing the symbolic link target for the given
+ * gcov data file name and link type. Depending on the link type and the
+ * location of the data file, the link target can either point to a
+ * subdirectory of srctree, objtree or in an external location.
+ */
+static char *get_link_target(const char *filename, const struct gcov_link *ext)
+{
+	const char *rel;
+	char *result;
+
+	if (strncmp(filename, objtree, strlen(objtree)) == 0) {
+		rel = filename + strlen(objtree) + 1;
+		if (ext->dir == SRC_TREE)
+			result = link_target(srctree, rel, ext->ext);
+		else
+			result = link_target(objtree, rel, ext->ext);
+	} else {
+		/* External compilation. */
+		result = link_target(NULL, filename, ext->ext);
+	}
+
+	return result;
+}
+
+#define SKEW_PREFIX	".tmp_"
+
+/*
+ * For a filename .tmp_filename.ext return filename.ext. Needed to compensate
+ * for filename skewing caused by the mod-versioning mechanism.
+ */
+static const char *deskew(const char *basename)
+{
+	if (strncmp(basename, SKEW_PREFIX, sizeof(SKEW_PREFIX) - 1) == 0)
+		return basename + sizeof(SKEW_PREFIX) - 1;
+	return basename;
+}
+
+/*
+ * Create links to additional files (usually .c and .gcno files) which the
+ * gcov tool expects to find in the same directory as the gcov data file.
+ */
+static void add_links(struct gcov_node *node, struct dentry *parent)
+{
+	const char *basename;
+	char *target;
+	int num;
+	int i;
+
+	for (num = 0; gcov_link[num].ext; num++)
+		/* Nothing. */;
+	node->links = kzalloc_objs(struct dentry *, num);
+	if (!node->links)
+		return;
+	for (i = 0; i < num; i++) {
+		target = get_link_target(
+				gcov_info_filename(get_node_info(node)),
+				&gcov_link[i]);
+		if (!target)
+			goto out_err;
+		basename = kbasename(target);
+		if (basename == target)
+			goto out_err;
+		node->links[i] = debugfs_create_symlink(deskew(basename),
+							parent,	target);
+		kfree(target);
+	}
+
+	return;
+out_err:
+	kfree(target);
+	while (i-- > 0)
+		debugfs_remove(node->links[i]);
+	kfree(node->links);
+	node->links = NULL;
+}
+
+static const struct file_operations gcov_data_fops = {
+	.open		= gcov_seq_open,
+	.release	= gcov_seq_release,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.write		= gcov_seq_write,
+};
+
+/* Basic initialization of a new node. */
+static void init_node(struct gcov_node *node, struct gcov_info *info,
+		      const char *name, struct gcov_node *parent)
+{
+	INIT_LIST_HEAD(&node->list);
+	INIT_LIST_HEAD(&node->children);
+	INIT_LIST_HEAD(&node->all);
+	if (node->loaded_info) {
+		node->loaded_info[0] = info;
+		node->num_loaded = 1;
+	}
+	node->parent = parent;
+	if (name)
+		strcpy(node->name, name);
+}
+
+/*
+ * Create a new node and associated debugfs entry. Needs to be called with
+ * node_lock held.
+ */
+static struct gcov_node *new_node(struct gcov_node *parent,
+				  struct gcov_info *info, const char *name)
+{
+	struct gcov_node *node;
+
+	node = kzalloc(sizeof(struct gcov_node) + strlen(name) + 1, GFP_KERNEL);
+	if (!node)
+		goto err_nomem;
+	if (info) {
+		node->loaded_info = kzalloc_objs(struct gcov_info *, 1);
+		if (!node->loaded_info)
+			goto err_nomem;
+	}
+	init_node(node, info, name, parent);
+	/* Differentiate between gcov data file nodes and directory nodes. */
+	if (info) {
+		node->dentry = debugfs_create_file(deskew(node->name), 0600,
+					parent->dentry, node, &gcov_data_fops);
+	} else
+		node->dentry = debugfs_create_dir(node->name, parent->dentry);
+	if (info)
+		add_links(node, parent->dentry);
+	list_add(&node->list, &parent->children);
+	list_add(&node->all, &all_head);
+
+	return node;
+
+err_nomem:
+	kfree(node);
+	pr_warn("out of memory\n");
+	return NULL;
+}
+
+/* Remove symbolic links associated with node. */
+static void remove_links(struct gcov_node *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;
+}
+
+/*
+ * Remove node from all lists and debugfs and release associated resources.
+ * Needs to be called with node_lock held.
+ */
+static void release_node(struct gcov_node *node)
+{
+	list_del(&node->list);
+	list_del(&node->all);
+	debugfs_remove(node->dentry);
+	remove_links(node);
+	kfree(node->loaded_info);
+	if (node->unloaded_info)
+		gcov_info_free(node->unloaded_info);
+	kfree(node);
+}
+
+/* Release node and empty parents. Needs to be called with node_lock held. */
+static void remove_node(struct gcov_node *node)
+{
+	struct gcov_node *parent;
+
+	while ((node != &root_node) && list_empty(&node->children)) {
+		parent = node->parent;
+		release_node(node);
+		node = parent;
+	}
+}
+
+/*
+ * Find child node with given basename. Needs to be called with node_lock
+ * held.
+ */
+static struct gcov_node *get_child_by_name(struct gcov_node *parent,
+					   const char *name)
+{
+	struct gcov_node *node;
+
+	list_for_each_entry(node, &parent->children, list) {
+		if (strcmp(node->name, name) == 0)
+			return node;
+	}
+
+	return NULL;
+}
+
+/*
+ * write() implementation for reset file. Reset all profiling data to zero
+ * and remove nodes for which all associated object files are unloaded.
+ */
+static ssize_t reset_write(struct file *file, const char __user *addr,
+			   size_t len, loff_t *pos)
+{
+	struct gcov_node *node;
+
+	mutex_lock(&node_lock);
+restart:
+	list_for_each_entry(node, &all_head, all) {
+		if (node->num_loaded > 0)
+			reset_node(node);
+		else if (list_empty(&node->children)) {
+			remove_node(node);
+			/* Several nodes may have gone - restart loop. */
+			goto restart;
+		}
+	}
+	mutex_unlock(&node_lock);
+
+	return len;
+}
+
+/* read() implementation for reset file. Unused. */
+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 const struct file_operations gcov_reset_fops = {
+	.write	= reset_write,
+	.read	= reset_read,
+	.llseek = noop_llseek,
+};
+
+/*
+ * Create a node for a given profiling data set and add it to all lists and
+ * debugfs. Needs to be called with node_lock held.
+ */
+static void add_node(struct gcov_info *info)
+{
+	char *filename;
+	char *curr;
+	char *next;
+	struct gcov_node *parent;
+	struct gcov_node *node;
+
+	filename = kstrdup(gcov_info_filename(info), GFP_KERNEL);
+	if (!filename)
+		return;
+	parent = &root_node;
+	/* Create directory nodes along the path. */
+	for (curr = filename; (next = strchr(curr, '/')); curr = next + 1) {
+		if (curr == next)
+			continue;
+		*next = 0;
+		if (strcmp(curr, ".") == 0)
+			continue;
+		if (strcmp(curr, "..") == 0) {
+			if (!parent->parent)
+				goto err_remove;
+			parent = parent->parent;
+			continue;
+		}
+		node = get_child_by_name(parent, curr);
+		if (!node) {
+			node = new_node(parent, NULL, curr);
+			if (!node)
+				goto err_remove;
+		}
+		parent = node;
+	}
+	/* Create file node. */
+	node = new_node(parent, info, curr);
+	if (!node)
+		goto err_remove;
+out:
+	kfree(filename);
+	return;
+
+err_remove:
+	remove_node(parent);
+	goto out;
+}
+
+/*
+ * Associate a profiling data set with an existing node. Needs to be called
+ * with node_lock held.
+ */
+static void add_info(struct gcov_node *node, struct gcov_info *info)
+{
+	struct gcov_info **loaded_info;
+	int num = node->num_loaded;
+
+	/*
+	 * Prepare new array. This is done first to simplify cleanup in
+	 * case the new data set is incompatible, the node only contains
+	 * unloaded data sets and there's not enough memory for the array.
+	 */
+	loaded_info = kzalloc_objs(struct gcov_info *, num + 1);
+	if (!loaded_info) {
+		pr_warn("could not add '%s' (out of memory)\n",
+			gcov_info_filename(info));
+		return;
+	}
+	memcpy(loaded_info, node->loaded_info,
+	       num * sizeof(struct gcov_info *));
+	loaded_info[num] = info;
+	/* Check if the new data set is compatible. */
+	if (num == 0) {
+		/*
+		 * A module was unloaded, modified and reloaded. The new
+		 * data set replaces the copy of the last one.
+		 */
+		if (!gcov_info_is_compatible(node->unloaded_info, info)) {
+			pr_warn("discarding saved data for %s "
+				"(incompatible version)\n",
+				gcov_info_filename(info));
+			gcov_info_free(node->unloaded_info);
+			node->unloaded_info = NULL;
+		}
+	} else {
+		/*
+		 * Two different versions of the same object file are loaded.
+		 * The initial one takes precedence.
+		 */
+		if (!gcov_info_is_compatible(node->loaded_info[0], info)) {
+			pr_warn("could not add '%s' (incompatible "
+				"version)\n", gcov_info_filename(info));
+			kfree(loaded_info);
+			return;
+		}
+	}
+	/* Overwrite previous array. */
+	kfree(node->loaded_info);
+	node->loaded_info = loaded_info;
+	node->num_loaded = num + 1;
+}
+
+/*
+ * Return the index of a profiling data set associated with a node.
+ */
+static int get_info_index(struct gcov_node *node, struct gcov_info *info)
+{
+	int i;
+
+	for (i = 0; i < node->num_loaded; i++) {
+		if (node->loaded_info[i] == info)
+			return i;
+	}
+	return -ENOENT;
+}
+
+/*
+ * Save the data of a profiling data set which is being unloaded.
+ */
+static void save_info(struct gcov_node *node, struct gcov_info *info)
+{
+	if (node->unloaded_info)
+		gcov_info_add(node->unloaded_info, info);
+	else {
+		node->unloaded_info = gcov_info_dup(info);
+		if (!node->unloaded_info) {
+			pr_warn("could not save data for '%s' "
+				"(out of memory)\n",
+				gcov_info_filename(info));
+		}
+	}
+}
+
+/*
+ * Disassociate a profiling data set from a node. Needs to be called with
+ * node_lock held.
+ */
+static void remove_info(struct gcov_node *node, struct gcov_info *info)
+{
+	int i;
+
+	i = get_info_index(node, info);
+	if (i < 0) {
+		pr_warn("could not remove '%s' (not found)\n",
+			gcov_info_filename(info));
+		return;
+	}
+	if (gcov_persist)
+		save_info(node, info);
+	/* Shrink array. */
+	node->loaded_info[i] = node->loaded_info[node->num_loaded - 1];
+	node->num_loaded--;
+	if (node->num_loaded > 0)
+		return;
+	/* Last loaded data set was removed. */
+	kfree(node->loaded_info);
+	node->loaded_info = NULL;
+	node->num_loaded = 0;
+	if (!node->unloaded_info)
+		remove_node(node);
+}
+
+/*
+ * Callback to create/remove profiling files when code compiled with
+ * -fprofile-arcs is loaded/unloaded.
+ */
+void gcov_event(enum gcov_action action, struct gcov_info *info)
+{
+	struct gcov_node *node;
+
+	mutex_lock(&node_lock);
+	node = get_node_by_name(gcov_info_filename(info));
+	switch (action) {
+	case GCOV_ADD:
+		if (node)
+			add_info(node, info);
+		else
+			add_node(info);
+		break;
+	case GCOV_REMOVE:
+		if (node)
+			remove_info(node, info);
+		else {
+			pr_warn("could not remove '%s' (not found)\n",
+				gcov_info_filename(info));
+		}
+		break;
+	}
+	mutex_unlock(&node_lock);
+}
+
+/* Create debugfs entries. */
+static __init int gcov_fs_init(void)
+{
+	init_node(&root_node, NULL, NULL, NULL);
+	/*
+	 * /sys/kernel/debug/gcov will be parent for the reset control file
+	 * and all profiling files.
+	 */
+	root_node.dentry = debugfs_create_dir("gcov", NULL);
+	/*
+	 * Create reset file which resets all profiling counts when written
+	 * to.
+	 */
+	debugfs_create_file("reset", 0600, root_node.dentry, NULL,
+			    &gcov_reset_fops);
+	/* Replay previous events to get our fs hierarchy up-to-date. */
+	gcov_enable_events();
+	return 0;
+}
+device_initcall(gcov_fs_init);

linux-7.2.3/kernel/gcov/gcc_4_7.c

@@ -0,0 +1,435 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  This code provides functions to handle gcc's profiling data format
+ *  introduced with gcc 4.7.
+ *
+ *  This file is based heavily on gcc_3_4.c file.
+ *
+ *  For a better understanding, refer to gcc source:
+ *  gcc/gcov-io.h
+ *  libgcc/libgcov.c
+ *
+ *  Uses gcc-internal data definitions.
+ */
+
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include "gcov.h"
+
+#if (__GNUC__ >= 15)
+#define GCOV_COUNTERS			10
+#elif (__GNUC__ >= 14)
+#define GCOV_COUNTERS			9
+#elif (__GNUC__ >= 10)
+#define GCOV_COUNTERS			8
+#else
+#define GCOV_COUNTERS			9
+#endif
+
+#define GCOV_TAG_FUNCTION_LENGTH	3
+
+/* Since GCC 12.1 sizes are in BYTES and not in WORDS (4B). */
+#if (__GNUC__ >= 12)
+#define GCOV_UNIT_SIZE				4
+#else
+#define GCOV_UNIT_SIZE				1
+#endif
+
+static struct gcov_info *gcov_info_head;
+
+/**
+ * struct gcov_ctr_info - information about counters for a single function
+ * @num: number of counter values for this type
+ * @values: array of counter values for this type
+ *
+ * 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;
+};
+
+/**
+ * struct gcov_fn_info - profiling meta data per function
+ * @key: comdat key
+ * @ident: unique ident of function
+ * @lineno_checksum: function lineo_checksum
+ * @cfg_checksum: function cfg checksum
+ * @ctrs: instrumented counters
+ *
+ * This data is generated by gcc during compilation and doesn't change
+ * at run-time.
+ *
+ * Information about a single function.  This uses the trailing array
+ * idiom. The number of counters is determined from the merge pointer
+ * array in gcov_info.  The key is used to detect which of a set of
+ * comdat functions was selected -- it points to the gcov_info object
+ * of the object file containing the selected comdat function.
+ */
+struct gcov_fn_info {
+	const struct gcov_info *key;
+	unsigned int ident;
+	unsigned int lineno_checksum;
+	unsigned int cfg_checksum;
+	struct gcov_ctr_info ctrs[];
+};
+
+/**
+ * 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: uniquifying time stamp
+ * @checksum: unique object checksum
+ * @filename: name of the associated gcov data file
+ * @merge: merge functions (null for unused counter type)
+ * @n_functions: number of instrumented functions
+ * @functions: pointer to pointers to function information
+ *
+ * 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;
+ /* Since GCC 12.1 a checksum field is added. */
+#if (__GNUC__ >= 12)
+	unsigned int checksum;
+#endif
+	const char *filename;
+	void (*merge[GCOV_COUNTERS])(gcov_type *, unsigned int);
+	unsigned int n_functions;
+	struct gcov_fn_info **functions;
+};
+
+/**
+ * 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;
+}
+
+/**
+ * gcov_info_within_module - check if a profiling data set belongs to a module
+ * @info: profiling data set
+ * @mod: module
+ *
+ * Returns true if profiling data belongs module, false otherwise.
+ */
+bool gcov_info_within_module(struct gcov_info *info, struct module *mod)
+{
+	return within_module((unsigned long)info, mod);
+}
+
+/* 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). */
+	{ 0, NULL},
+};
+
+/*
+ * Determine whether a counter is active. Doesn't change at run-time.
+ */
+static int counter_active(struct gcov_info *info, unsigned int type)
+{
+	return info->merge[type] ? 1 : 0;
+}
+
+/* Determine number of active counters. Based on gcc magic. */
+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 to zero
+ * @info: profiling data set
+ */
+void gcov_info_reset(struct gcov_info *info)
+{
+	struct gcov_ctr_info *ci_ptr;
+	unsigned int fi_idx;
+	unsigned int ct_idx;
+
+	for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
+		ci_ptr = info->functions[fi_idx]->ctrs;
+
+		for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
+			if (!counter_active(info, ct_idx))
+				continue;
+
+			memset(ci_ptr->values, 0,
+					sizeof(gcov_type) * ci_ptr->num);
+			ci_ptr++;
+		}
+	}
+}
+
+/**
+ * gcov_info_is_compatible - check if profiling data can be added
+ * @info1: first profiling data set
+ * @info2: 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
+ * @dst: profiling data set to which data is added
+ * @src: profiling data set which is added
+ *
+ * Adds profiling counts of @src to @dst.
+ */
+void gcov_info_add(struct gcov_info *dst, struct gcov_info *src)
+{
+	struct gcov_ctr_info *dci_ptr;
+	struct gcov_ctr_info *sci_ptr;
+	unsigned int fi_idx;
+	unsigned int ct_idx;
+	unsigned int val_idx;
+
+	for (fi_idx = 0; fi_idx < src->n_functions; fi_idx++) {
+		dci_ptr = dst->functions[fi_idx]->ctrs;
+		sci_ptr = src->functions[fi_idx]->ctrs;
+
+		for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
+			if (!counter_active(src, ct_idx))
+				continue;
+
+			for (val_idx = 0; val_idx < sci_ptr->num; val_idx++)
+				dci_ptr->values[val_idx] +=
+					sci_ptr->values[val_idx];
+
+			dci_ptr++;
+			sci_ptr++;
+		}
+	}
+}
+
+/**
+ * gcov_info_dup - duplicate profiling data set
+ * @info: profiling data set to duplicate
+ *
+ * Return newly allocated duplicate on success, %NULL on error.
+ */
+struct gcov_info *gcov_info_dup(struct gcov_info *info)
+{
+	struct gcov_info *dup;
+	struct gcov_ctr_info *dci_ptr; /* dst counter info */
+	struct gcov_ctr_info *sci_ptr; /* src counter info */
+	unsigned int active;
+	unsigned int fi_idx; /* function info idx */
+	unsigned int ct_idx; /* counter type idx */
+	size_t fi_size; /* function info size */
+	size_t cv_size; /* counter values size */
+
+	dup = kmemdup(info, sizeof(*dup), GFP_KERNEL);
+	if (!dup)
+		return NULL;
+
+	dup->next = NULL;
+	dup->filename = NULL;
+	dup->functions = NULL;
+
+	dup->filename = kstrdup(info->filename, GFP_KERNEL);
+	if (!dup->filename)
+		goto err_free;
+
+	dup->functions = kzalloc_objs(struct gcov_fn_info *, info->n_functions);
+	if (!dup->functions)
+		goto err_free;
+
+	active = num_counter_active(info);
+	fi_size = sizeof(struct gcov_fn_info);
+	fi_size += sizeof(struct gcov_ctr_info) * active;
+
+	for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
+		dup->functions[fi_idx] = kzalloc(fi_size, GFP_KERNEL);
+		if (!dup->functions[fi_idx])
+			goto err_free;
+
+		*(dup->functions[fi_idx]) = *(info->functions[fi_idx]);
+
+		sci_ptr = info->functions[fi_idx]->ctrs;
+		dci_ptr = dup->functions[fi_idx]->ctrs;
+
+		for (ct_idx = 0; ct_idx < active; ct_idx++) {
+
+			cv_size = sizeof(gcov_type) * sci_ptr->num;
+
+			dci_ptr->values = kvmalloc(cv_size, GFP_KERNEL);
+
+			if (!dci_ptr->values)
+				goto err_free;
+
+			dci_ptr->num = sci_ptr->num;
+			memcpy(dci_ptr->values, sci_ptr->values, cv_size);
+
+			sci_ptr++;
+			dci_ptr++;
+		}
+	}
+
+	return dup;
+err_free:
+	gcov_info_free(dup);
+	return NULL;
+}
+
+/**
+ * gcov_info_free - release memory for profiling data set duplicate
+ * @info: profiling data set duplicate to free
+ */
+void gcov_info_free(struct gcov_info *info)
+{
+	unsigned int active;
+	unsigned int fi_idx;
+	unsigned int ct_idx;
+	struct gcov_ctr_info *ci_ptr;
+
+	if (!info->functions)
+		goto free_info;
+
+	active = num_counter_active(info);
+
+	for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
+		if (!info->functions[fi_idx])
+			continue;
+
+		ci_ptr = info->functions[fi_idx]->ctrs;
+
+		for (ct_idx = 0; ct_idx < active; ct_idx++, ci_ptr++)
+			kvfree(ci_ptr->values);
+
+		kfree(info->functions[fi_idx]);
+	}
+
+free_info:
+	kfree(info->functions);
+	kfree(info->filename);
+	kfree(info);
+}
+
+/**
+ * convert_to_gcda - convert profiling data set to gcda file format
+ * @buffer: the buffer to store file data or %NULL if no data should be stored
+ * @info: profiling data set to be converted
+ *
+ * Returns the number of bytes that were/would have been stored into the buffer.
+ */
+size_t convert_to_gcda(char *buffer, struct gcov_info *info)
+{
+	struct gcov_fn_info *fi_ptr;
+	struct gcov_ctr_info *ci_ptr;
+	unsigned int fi_idx;
+	unsigned int ct_idx;
+	unsigned int cv_idx;
+	size_t pos = 0;
+
+	/* File header. */
+	pos += store_gcov_u32(buffer, pos, GCOV_DATA_MAGIC);
+	pos += store_gcov_u32(buffer, pos, info->version);
+	pos += store_gcov_u32(buffer, pos, info->stamp);
+
+#if (__GNUC__ >= 12)
+	/* Use zero as checksum of the compilation unit. */
+	pos += store_gcov_u32(buffer, pos, 0);
+#endif
+
+	for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
+		fi_ptr = info->functions[fi_idx];
+
+		/* Function record. */
+		pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION);
+		pos += store_gcov_u32(buffer, pos,
+			GCOV_TAG_FUNCTION_LENGTH * GCOV_UNIT_SIZE);
+		pos += store_gcov_u32(buffer, pos, fi_ptr->ident);
+		pos += store_gcov_u32(buffer, pos, fi_ptr->lineno_checksum);
+		pos += store_gcov_u32(buffer, pos, fi_ptr->cfg_checksum);
+
+		ci_ptr = fi_ptr->ctrs;
+
+		for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
+			if (!counter_active(info, ct_idx))
+				continue;
+
+			/* Counter record. */
+			pos += store_gcov_u32(buffer, pos,
+					      GCOV_TAG_FOR_COUNTER(ct_idx));
+			pos += store_gcov_u32(buffer, pos,
+				ci_ptr->num * 2 * GCOV_UNIT_SIZE);
+
+			for (cv_idx = 0; cv_idx < ci_ptr->num; cv_idx++) {
+				pos += store_gcov_u64(buffer, pos,
+						      ci_ptr->values[cv_idx]);
+			}
+
+			ci_ptr++;
+		}
+	}
+
+	return pos;
+}

linux-7.2.3/kernel/gcov/gcc_base.c

@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/mutex.h>
+#include "gcov.h"
+
+/*
+ * __gcov_init is called by gcc-generated constructor code for each object
+ * file compiled with -fprofile-arcs.
+ */
+void __gcov_init(struct gcov_info *info)
+{
+	static unsigned int gcov_version;
+
+	mutex_lock(&gcov_lock);
+	if (gcov_version == 0) {
+		gcov_version = gcov_info_version(info);
+		/*
+		 * Printing gcc's version magic may prove useful for debugging
+		 * incompatibility reports.
+		 */
+		pr_info("version magic: 0x%x\n", gcov_version);
+	}
+	/*
+	 * Add new profiling data structure to list and inform event
+	 * listener.
+	 */
+	gcov_info_link(info);
+	if (gcov_events_enabled)
+		gcov_event(GCOV_ADD, info);
+	mutex_unlock(&gcov_lock);
+}
+EXPORT_SYMBOL(__gcov_init);
+
+/*
+ * These functions may be referenced by gcc-generated 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);
+
+void __gcov_merge_ior(gcov_type *counters, unsigned int n_counters)
+{
+	/* Unused. */
+}
+EXPORT_SYMBOL(__gcov_merge_ior);
+
+void __gcov_merge_time_profile(gcov_type *counters, unsigned int n_counters)
+{
+	/* Unused. */
+}
+EXPORT_SYMBOL(__gcov_merge_time_profile);
+
+void __gcov_merge_icall_topn(gcov_type *counters, unsigned int n_counters)
+{
+	/* Unused. */
+}
+EXPORT_SYMBOL(__gcov_merge_icall_topn);
+
+void __gcov_exit(void)
+{
+	/* Unused. */
+}
+EXPORT_SYMBOL(__gcov_exit);

linux-7.2.3/kernel/gcov/gcov.h

@@ -0,0 +1,85 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ *  Profiling infrastructure declarations.
+ *
+ *  This file is based on gcc-internal definitions. Data structures are
+ *  defined to be compatible with gcc counterparts. For a better
+ *  understanding, refer to gcc source: gcc/gcov-io.h.
+ *
+ *    Copyright IBM Corp. 2009
+ *    Author(s): Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
+ *
+ *    Uses gcc-internal data definitions.
+ */
+
+#ifndef GCOV_H
+#define GCOV_H GCOV_H
+
+#include <linux/module.h>
+#include <linux/types.h>
+
+/*
+ * Profiling data types used for gcc 3.4 and above - these are defined by
+ * gcc and need to be kept as close to the original definition as possible to
+ * remain compatible.
+ */
+#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
+
+/* 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;
+
+/* 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);
+bool gcov_info_within_module(struct gcov_info *info, struct module *mod);
+size_t convert_to_gcda(char *buffer, struct gcov_info *info);
+
+/* Base interface. */
+enum gcov_action {
+	GCOV_ADD,
+	GCOV_REMOVE,
+};
+
+void gcov_event(enum gcov_action action, struct gcov_info *info);
+void gcov_enable_events(void);
+
+/* writing helpers */
+size_t store_gcov_u32(void *buffer, size_t off, u32 v);
+size_t store_gcov_u64(void *buffer, size_t off, u64 v);
+
+/* gcov_info control. */
+void gcov_info_reset(struct gcov_info *info);
+int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2);
+void gcov_info_add(struct gcov_info *dest, struct gcov_info *source);
+struct gcov_info *gcov_info_dup(struct gcov_info *info);
+void gcov_info_free(struct gcov_info *info);
+
+struct gcov_link {
+	enum {
+		OBJ_TREE,
+		SRC_TREE,
+	} dir;
+	const char *ext;
+};
+extern const struct gcov_link gcov_link[];
+
+extern int gcov_events_enabled;
+extern struct mutex gcov_lock;
+
+#endif /* GCOV_H */