// 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__ >= 10)
#define GCOV_COUNTERS 8
#elif (__GNUC__ >= 7)
#define GCOV_COUNTERS 9
#elif (__GNUC__ > 5) || (__GNUC__ == 5 && __GNUC_MINOR__ >= 1)
#define GCOV_COUNTERS 10
#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 = kcalloc(info->n_functions,
sizeof(struct gcov_fn_info *), GFP_KERNEL);
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;
}
