// 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/seq_file.h>
#include <linux/slab.h>
#include <linux/vmalloc.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;
u8 use_extra_checksum;
u32 cfg_checksum;
u32 num_counters;
u64 *counters;
const char *function_name;
};
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, const char version[4],
u32 checksum)
{
current_info->filename = orig_filename;
memcpy(¤t_info->version, version, sizeof(current_info->version));
current_info->checksum = checksum;
}
EXPORT_SYMBOL(llvm_gcda_start_file);
void llvm_gcda_emit_function(u32 ident, const char *function_name,
u32 func_checksum, u8 use_extra_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->use_extra_checksum = use_extra_checksum;
info->cfg_checksum = cfg_checksum;
if (function_name)
info->function_name = kstrdup(function_name, GFP_KERNEL);
list_add_tail(&info->head, ¤t_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(¤t_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->use_extra_checksum != fn_ptr2->use_extra_checksum)
return false;
if (fn_ptr1->use_extra_checksum &&
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];
}
}
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);
fn_dup->function_name = kstrdup(fn->function_name, GFP_KERNEL);
if (!fn_dup->function_name)
goto err_name;
cv_size = fn->num_counters * sizeof(fn->counters[0]);
fn_dup->counters = vmalloc(cv_size);
if (!fn_dup->counters)
goto err_counters;
memcpy(fn_dup->counters, fn->counters, cv_size);
return fn_dup;
err_counters:
kfree(fn_dup->function_name);
err_name:
kfree(fn_dup);
return NULL;
}
/**
* 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) {
kfree(fn->function_name);
vfree(fn->counters);
list_del(&fn->head);
kfree(fn);
}
kfree(info->filename);
kfree(info);
}
#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;
void *buffer;
size_t size;
loff_t pos;
};
/**
* 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.
*/
static 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.
*/
static 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;
}
/**
* 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.
*/
static 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;
u32 len = 2;
if (fi_ptr->use_extra_checksum)
len++;
pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION);
pos += store_gcov_u32(buffer, pos, len);
pos += store_gcov_u32(buffer, pos, fi_ptr->ident);
pos += store_gcov_u32(buffer, pos, fi_ptr->checksum);
if (fi_ptr->use_extra_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;
}
/**
* gcov_iter_new - allocate and initialize profiling data iterator
* @info: profiling data set to be iterated
*
* Return file iterator on success, %NULL otherwise.
*/
struct gcov_iterator *gcov_iter_new(struct gcov_info *info)
{
struct gcov_iterator *iter;
iter = kzalloc(sizeof(struct gcov_iterator), GFP_KERNEL);
if (!iter)
goto err_free;
iter->info = info;
/* Dry-run to get the actual buffer size. */
iter->size = convert_to_gcda(NULL, info);
iter->buffer = vmalloc(iter->size);
if (!iter->buffer)
goto err_free;
convert_to_gcda(iter->buffer, info);
return iter;
err_free:
kfree(iter);
return NULL;
}
/**
* gcov_iter_get_info - return profiling data set for given file iterator
* @iter: file iterator
*/
void gcov_iter_free(struct gcov_iterator *iter)
{
vfree(iter->buffer);
kfree(iter);
}
/**
* gcov_iter_get_info - return profiling data set for given file iterator
* @iter: file iterator
*/
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
*/
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.
*/
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.
*/
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;
}
