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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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![Nick Desaulniers](/assets/img/avatar_default.png)
LLVM changed the expected function signatures for llvm_gcda_start_file() and llvm_gcda_emit_function() in the clang-11 release. Users of clang-11 or newer may have noticed their kernels failing to boot due to a panic when enabling CONFIG_GCOV_KERNEL=y +CONFIG_GCOV_PROFILE_ALL=y. Fix up the function signatures so calling these functions doesn't panic the kernel. Link: https://reviews.llvm.org/rGcdd683b516d147925212724b09ec6fb792a40041 Link: https://reviews.llvm.org/rG13a633b438b6500ecad9e4f936ebadf3411d0f44 Link: https://lkml.kernel.org/r/20210312224132.3413602-2-ndesaulniers@google.com Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Reported-by: Prasad Sodagudi <psodagud@quicinc.com> Suggested-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Fangrui Song <maskray@google.com> Tested-by: Nathan Chancellor <nathan@kernel.org> Acked-by: Peter Oberparleiter <oberpar@linux.ibm.com> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Cc: <stable@vger.kernel.org> [5.4+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
650 lines
16 KiB
C
650 lines
16 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2019 Google, Inc.
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* modified from kernel/gcov/gcc_4_7.c
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*
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* LLVM uses profiling data that's deliberately similar to GCC, but has a
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* very different way of exporting that data. LLVM calls llvm_gcov_init() once
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* per module, and provides a couple of callbacks that we can use to ask for
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* more data.
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*
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* We care about the "writeout" callback, which in turn calls back into
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* compiler-rt/this module to dump all the gathered coverage data to disk:
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*
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* llvm_gcda_start_file()
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* llvm_gcda_emit_function()
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* llvm_gcda_emit_arcs()
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* llvm_gcda_emit_function()
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* llvm_gcda_emit_arcs()
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* [... repeats for each function ...]
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* llvm_gcda_summary_info()
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* llvm_gcda_end_file()
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*
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* This design is much more stateless and unstructured than gcc's, and is
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* intended to run at process exit. This forces us to keep some local state
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* about which module we're dealing with at the moment. On the other hand, it
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* also means we don't depend as much on how LLVM represents profiling data
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* internally.
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*
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* See LLVM's lib/Transforms/Instrumentation/GCOVProfiling.cpp for more
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* details on how this works, particularly GCOVProfiler::emitProfileArcs(),
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* GCOVProfiler::insertCounterWriteout(), and
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* GCOVProfiler::insertFlush().
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*/
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#define pr_fmt(fmt) "gcov: " fmt
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#include <linux/kernel.h>
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#include <linux/list.h>
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#include <linux/printk.h>
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#include <linux/ratelimit.h>
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#include <linux/seq_file.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include "gcov.h"
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typedef void (*llvm_gcov_callback)(void);
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struct gcov_info {
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struct list_head head;
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const char *filename;
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unsigned int version;
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u32 checksum;
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struct list_head functions;
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};
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struct gcov_fn_info {
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struct list_head head;
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u32 ident;
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u32 checksum;
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u8 use_extra_checksum;
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u32 cfg_checksum;
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u32 num_counters;
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u64 *counters;
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#if CONFIG_CLANG_VERSION < 110000
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const char *function_name;
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#endif
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};
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static struct gcov_info *current_info;
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static LIST_HEAD(clang_gcov_list);
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void llvm_gcov_init(llvm_gcov_callback writeout, llvm_gcov_callback flush)
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{
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struct gcov_info *info = kzalloc(sizeof(*info), GFP_KERNEL);
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if (!info)
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return;
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INIT_LIST_HEAD(&info->head);
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INIT_LIST_HEAD(&info->functions);
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mutex_lock(&gcov_lock);
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list_add_tail(&info->head, &clang_gcov_list);
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current_info = info;
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writeout();
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current_info = NULL;
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if (gcov_events_enabled)
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gcov_event(GCOV_ADD, info);
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mutex_unlock(&gcov_lock);
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}
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EXPORT_SYMBOL(llvm_gcov_init);
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#if CONFIG_CLANG_VERSION < 110000
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void llvm_gcda_start_file(const char *orig_filename, const char version[4],
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u32 checksum)
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{
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current_info->filename = orig_filename;
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memcpy(¤t_info->version, version, sizeof(current_info->version));
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current_info->checksum = checksum;
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}
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EXPORT_SYMBOL(llvm_gcda_start_file);
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#else
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void llvm_gcda_start_file(const char *orig_filename, u32 version, u32 checksum)
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{
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current_info->filename = orig_filename;
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current_info->version = version;
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current_info->checksum = checksum;
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}
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EXPORT_SYMBOL(llvm_gcda_start_file);
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#endif
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#if CONFIG_CLANG_VERSION < 110000
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void llvm_gcda_emit_function(u32 ident, const char *function_name,
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u32 func_checksum, u8 use_extra_checksum, u32 cfg_checksum)
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{
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struct gcov_fn_info *info = kzalloc(sizeof(*info), GFP_KERNEL);
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if (!info)
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return;
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INIT_LIST_HEAD(&info->head);
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info->ident = ident;
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info->checksum = func_checksum;
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info->use_extra_checksum = use_extra_checksum;
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info->cfg_checksum = cfg_checksum;
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if (function_name)
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info->function_name = kstrdup(function_name, GFP_KERNEL);
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list_add_tail(&info->head, ¤t_info->functions);
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}
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EXPORT_SYMBOL(llvm_gcda_emit_function);
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#else
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void llvm_gcda_emit_function(u32 ident, u32 func_checksum,
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u8 use_extra_checksum, u32 cfg_checksum)
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{
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struct gcov_fn_info *info = kzalloc(sizeof(*info), GFP_KERNEL);
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if (!info)
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return;
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INIT_LIST_HEAD(&info->head);
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info->ident = ident;
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info->checksum = func_checksum;
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info->use_extra_checksum = use_extra_checksum;
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info->cfg_checksum = cfg_checksum;
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list_add_tail(&info->head, ¤t_info->functions);
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}
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EXPORT_SYMBOL(llvm_gcda_emit_function);
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#endif
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void llvm_gcda_emit_arcs(u32 num_counters, u64 *counters)
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{
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struct gcov_fn_info *info = list_last_entry(¤t_info->functions,
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struct gcov_fn_info, head);
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info->num_counters = num_counters;
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info->counters = counters;
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}
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EXPORT_SYMBOL(llvm_gcda_emit_arcs);
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void llvm_gcda_summary_info(void)
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{
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}
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EXPORT_SYMBOL(llvm_gcda_summary_info);
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void llvm_gcda_end_file(void)
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{
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}
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EXPORT_SYMBOL(llvm_gcda_end_file);
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/**
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* gcov_info_filename - return info filename
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* @info: profiling data set
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*/
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const char *gcov_info_filename(struct gcov_info *info)
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{
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return info->filename;
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}
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/**
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* gcov_info_version - return info version
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* @info: profiling data set
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*/
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unsigned int gcov_info_version(struct gcov_info *info)
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{
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return info->version;
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}
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/**
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* gcov_info_next - return next profiling data set
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* @info: profiling data set
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*
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* Returns next gcov_info following @info or first gcov_info in the chain if
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* @info is %NULL.
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*/
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struct gcov_info *gcov_info_next(struct gcov_info *info)
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{
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if (!info)
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return list_first_entry_or_null(&clang_gcov_list,
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struct gcov_info, head);
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if (list_is_last(&info->head, &clang_gcov_list))
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return NULL;
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return list_next_entry(info, head);
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}
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/**
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* gcov_info_link - link/add profiling data set to the list
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* @info: profiling data set
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*/
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void gcov_info_link(struct gcov_info *info)
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{
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list_add_tail(&info->head, &clang_gcov_list);
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}
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/**
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* gcov_info_unlink - unlink/remove profiling data set from the list
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* @prev: previous profiling data set
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* @info: profiling data set
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*/
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void gcov_info_unlink(struct gcov_info *prev, struct gcov_info *info)
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{
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/* Generic code unlinks while iterating. */
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__list_del_entry(&info->head);
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}
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/**
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* gcov_info_within_module - check if a profiling data set belongs to a module
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* @info: profiling data set
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* @mod: module
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*
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* Returns true if profiling data belongs module, false otherwise.
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*/
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bool gcov_info_within_module(struct gcov_info *info, struct module *mod)
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{
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return within_module((unsigned long)info->filename, mod);
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}
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/* Symbolic links to be created for each profiling data file. */
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const struct gcov_link gcov_link[] = {
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{ OBJ_TREE, "gcno" }, /* Link to .gcno file in $(objtree). */
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{ 0, NULL},
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};
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/**
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* gcov_info_reset - reset profiling data to zero
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* @info: profiling data set
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*/
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void gcov_info_reset(struct gcov_info *info)
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{
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struct gcov_fn_info *fn;
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list_for_each_entry(fn, &info->functions, head)
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memset(fn->counters, 0,
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sizeof(fn->counters[0]) * fn->num_counters);
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}
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/**
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* gcov_info_is_compatible - check if profiling data can be added
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* @info1: first profiling data set
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* @info2: second profiling data set
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*
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* Returns non-zero if profiling data can be added, zero otherwise.
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*/
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int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2)
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{
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struct gcov_fn_info *fn_ptr1 = list_first_entry_or_null(
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&info1->functions, struct gcov_fn_info, head);
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struct gcov_fn_info *fn_ptr2 = list_first_entry_or_null(
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&info2->functions, struct gcov_fn_info, head);
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if (info1->checksum != info2->checksum)
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return false;
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if (!fn_ptr1)
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return fn_ptr1 == fn_ptr2;
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while (!list_is_last(&fn_ptr1->head, &info1->functions) &&
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!list_is_last(&fn_ptr2->head, &info2->functions)) {
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if (fn_ptr1->checksum != fn_ptr2->checksum)
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return false;
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if (fn_ptr1->use_extra_checksum != fn_ptr2->use_extra_checksum)
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return false;
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if (fn_ptr1->use_extra_checksum &&
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fn_ptr1->cfg_checksum != fn_ptr2->cfg_checksum)
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return false;
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fn_ptr1 = list_next_entry(fn_ptr1, head);
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fn_ptr2 = list_next_entry(fn_ptr2, head);
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}
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return list_is_last(&fn_ptr1->head, &info1->functions) &&
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list_is_last(&fn_ptr2->head, &info2->functions);
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}
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/**
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* gcov_info_add - add up profiling data
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* @dest: profiling data set to which data is added
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* @source: profiling data set which is added
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*
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* Adds profiling counts of @source to @dest.
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*/
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void gcov_info_add(struct gcov_info *dst, struct gcov_info *src)
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{
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struct gcov_fn_info *dfn_ptr;
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struct gcov_fn_info *sfn_ptr = list_first_entry_or_null(&src->functions,
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struct gcov_fn_info, head);
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list_for_each_entry(dfn_ptr, &dst->functions, head) {
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u32 i;
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for (i = 0; i < sfn_ptr->num_counters; i++)
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dfn_ptr->counters[i] += sfn_ptr->counters[i];
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}
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}
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#if CONFIG_CLANG_VERSION < 110000
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static struct gcov_fn_info *gcov_fn_info_dup(struct gcov_fn_info *fn)
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{
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size_t cv_size; /* counter values size */
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struct gcov_fn_info *fn_dup = kmemdup(fn, sizeof(*fn),
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GFP_KERNEL);
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if (!fn_dup)
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return NULL;
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INIT_LIST_HEAD(&fn_dup->head);
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fn_dup->function_name = kstrdup(fn->function_name, GFP_KERNEL);
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if (!fn_dup->function_name)
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goto err_name;
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cv_size = fn->num_counters * sizeof(fn->counters[0]);
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fn_dup->counters = vmalloc(cv_size);
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if (!fn_dup->counters)
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goto err_counters;
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memcpy(fn_dup->counters, fn->counters, cv_size);
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return fn_dup;
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err_counters:
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kfree(fn_dup->function_name);
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err_name:
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kfree(fn_dup);
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return NULL;
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}
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#else
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static struct gcov_fn_info *gcov_fn_info_dup(struct gcov_fn_info *fn)
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{
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size_t cv_size; /* counter values size */
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struct gcov_fn_info *fn_dup = kmemdup(fn, sizeof(*fn),
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GFP_KERNEL);
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if (!fn_dup)
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return NULL;
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INIT_LIST_HEAD(&fn_dup->head);
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cv_size = fn->num_counters * sizeof(fn->counters[0]);
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fn_dup->counters = vmalloc(cv_size);
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if (!fn_dup->counters) {
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kfree(fn_dup);
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return NULL;
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}
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memcpy(fn_dup->counters, fn->counters, cv_size);
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return fn_dup;
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}
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#endif
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/**
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* gcov_info_dup - duplicate profiling data set
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* @info: profiling data set to duplicate
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*
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* Return newly allocated duplicate on success, %NULL on error.
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*/
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struct gcov_info *gcov_info_dup(struct gcov_info *info)
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{
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struct gcov_info *dup;
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struct gcov_fn_info *fn;
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dup = kmemdup(info, sizeof(*dup), GFP_KERNEL);
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if (!dup)
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return NULL;
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INIT_LIST_HEAD(&dup->head);
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INIT_LIST_HEAD(&dup->functions);
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dup->filename = kstrdup(info->filename, GFP_KERNEL);
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if (!dup->filename)
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goto err;
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list_for_each_entry(fn, &info->functions, head) {
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struct gcov_fn_info *fn_dup = gcov_fn_info_dup(fn);
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if (!fn_dup)
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goto err;
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list_add_tail(&fn_dup->head, &dup->functions);
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}
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return dup;
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err:
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gcov_info_free(dup);
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return NULL;
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}
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/**
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* gcov_info_free - release memory for profiling data set duplicate
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* @info: profiling data set duplicate to free
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*/
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#if CONFIG_CLANG_VERSION < 110000
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void gcov_info_free(struct gcov_info *info)
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{
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struct gcov_fn_info *fn, *tmp;
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list_for_each_entry_safe(fn, tmp, &info->functions, head) {
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kfree(fn->function_name);
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vfree(fn->counters);
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list_del(&fn->head);
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kfree(fn);
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}
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kfree(info->filename);
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kfree(info);
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}
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#else
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void gcov_info_free(struct gcov_info *info)
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{
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struct gcov_fn_info *fn, *tmp;
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list_for_each_entry_safe(fn, tmp, &info->functions, head) {
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vfree(fn->counters);
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list_del(&fn->head);
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kfree(fn);
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}
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kfree(info->filename);
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kfree(info);
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}
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#endif
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#define ITER_STRIDE PAGE_SIZE
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/**
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* struct gcov_iterator - specifies current file position in logical records
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* @info: associated profiling data
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* @buffer: buffer containing file data
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* @size: size of buffer
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* @pos: current position in file
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*/
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struct gcov_iterator {
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struct gcov_info *info;
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void *buffer;
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size_t size;
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loff_t pos;
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};
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/**
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* store_gcov_u32 - store 32 bit number in gcov format to buffer
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* @buffer: target buffer or NULL
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* @off: offset into the buffer
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* @v: value to be stored
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*
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* Number format defined by gcc: numbers are recorded in the 32 bit
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* unsigned binary form of the endianness of the machine generating the
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* file. Returns the number of bytes stored. If @buffer is %NULL, doesn't
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* store anything.
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*/
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static size_t store_gcov_u32(void *buffer, size_t off, u32 v)
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{
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u32 *data;
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if (buffer) {
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data = buffer + off;
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*data = v;
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}
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return sizeof(*data);
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}
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/**
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* store_gcov_u64 - store 64 bit number in gcov format to buffer
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* @buffer: target buffer or NULL
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* @off: offset into the buffer
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* @v: value to be stored
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*
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* Number format defined by gcc: numbers are recorded in the 32 bit
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* 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;
|
|
}
|