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-rw-r--r--kernel/gcov/clang.c393
1 files changed, 393 insertions, 0 deletions
diff --git a/kernel/gcov/clang.c b/kernel/gcov/clang.c
new file mode 100644
index 000000000..7670a811a
--- /dev/null
+++ b/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(sizeof(*info), GFP_KERNEL);
+
+ 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(sizeof(*info), GFP_KERNEL);
+
+ 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
+ * @dest: profiling data set to which data is added
+ * @source: profiling data set which is added
+ *
+ * Adds profiling counts of @source to @dest.
+ */
+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;
+}