diff options
Diffstat (limited to 'kernel/gcov/clang.c')
| -rw-r--r-- | kernel/gcov/clang.c | 661 |
1 files changed, 661 insertions, 0 deletions
diff --git a/kernel/gcov/clang.c b/kernel/gcov/clang.c new file mode 100644 index 000000000..ea6b45d0f --- /dev/null +++ b/kernel/gcov/clang.c @@ -0,0 +1,661 @@ +// 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; +#if CONFIG_CLANG_VERSION < 110000 + u8 use_extra_checksum; +#endif + u32 cfg_checksum; + + u32 num_counters; + u64 *counters; +#if CONFIG_CLANG_VERSION < 110000 + const char *function_name; +#endif +}; + +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); + +#if CONFIG_CLANG_VERSION < 110000 +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); +#else +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); +#endif + +#if CONFIG_CLANG_VERSION < 110000 +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); +} +#else +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, ¤t_info->functions); +} +#endif +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 CONFIG_CLANG_VERSION < 110000 + 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; +#else + if (fn_ptr1->cfg_checksum != fn_ptr2->cfg_checksum) + return false; +#endif + 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); + } +} + +#if CONFIG_CLANG_VERSION < 110000 +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; +} +#else +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 = vmalloc(cv_size); + if (!fn_dup->counters) { + kfree(fn_dup); + return NULL; + } + + memcpy(fn_dup->counters, fn->counters, cv_size); + + return fn_dup; +} +#endif + +/** + * 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 + */ +#if CONFIG_CLANG_VERSION < 110000 +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); +} +#else +void gcov_info_free(struct gcov_info *info) +{ + struct gcov_fn_info *fn, *tmp; + + list_for_each_entry_safe(fn, tmp, &info->functions, head) { + vfree(fn->counters); + list_del(&fn->head); + kfree(fn); + } + kfree(info->filename); + kfree(info); +} +#endif + +#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; + + pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION); +#if CONFIG_CLANG_VERSION < 110000 + pos += store_gcov_u32(buffer, pos, + fi_ptr->use_extra_checksum ? 3 : 2); +#else + pos += store_gcov_u32(buffer, pos, 3); +#endif + pos += store_gcov_u32(buffer, pos, fi_ptr->ident); + pos += store_gcov_u32(buffer, pos, fi_ptr->checksum); +#if CONFIG_CLANG_VERSION < 110000 + if (fi_ptr->use_extra_checksum) + pos += store_gcov_u32(buffer, pos, fi_ptr->cfg_checksum); +#else + pos += store_gcov_u32(buffer, pos, fi_ptr->cfg_checksum); +#endif + + 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; +} |