MAJOR=13 MINOR=65 DEVNAME=input/event1 *l4( (  fB- tL_I|+E/* SPDX-License-Identifier: GPL-2.0-or-later */ /* * Stack depot - a stack trace storage that avoids duplication. * * Stack depot is intended to be used by subsystems that need to store and * later retrieve many potentially duplicated stack traces without wasting * memory. * * For example, KASAN needs to save allocation and free stack traces for each * object. Storing two stack traces per object requires a lot of memory (e.g. * SLUB_DEBUG needs 256 bytes per object for that). Since allocation and free * stack traces often repeat, using stack depot allows to save about 100x space. * * Author: Alexander Potapenko * Copyright (C) 2016 Google, Inc. * * Based on the code by Dmitry Chernenkov. */ #ifndef _LINUX_STACKDEPOT_H #define _LINUX_STACKDEPOT_H #include typedef u32 depot_stack_handle_t; /* * Number of bits in the handle that stack depot doesn't use. Users may store * information in them via stack_depot_set/get_extra_bits. */ #define STACK_DEPOT_EXTRA_BITS 5 typedef u32 depot_flags_t; /* * Flags that can be passed to stack_depot_save_flags(); see the comment next * to its declaration for more details. */ #define STACK_DEPOT_FLAG_CAN_ALLOC ((depot_flags_t)0x0001) #define STACK_DEPOT_FLAG_GET ((depot_flags_t)0x0002) #define STACK_DEPOT_FLAGS_NUM 2 #define STACK_DEPOT_FLAGS_MASK ((depot_flags_t)((1 << STACK_DEPOT_FLAGS_NUM) - 1)) /* * Using stack depot requires its initialization, which can be done in 3 ways: * * 1. Selecting CONFIG_STACKDEPOT_ALWAYS_INIT. This option is suitable in * scenarios where it's known at compile time that stack depot will be used. * Enabling this config makes the kernel initialize stack depot in mm_init(). * * 2. Calling stack_depot_request_early_init() during early boot, before * stack_depot_early_init() in mm_init() completes. For example, this can * be done when evaluating kernel boot parameters. * * 3. Calling stack_depot_init(). Possible after boot is complete. This option * is recommended for modules initialized later in the boot process, after * mm_init() completes. * * stack_depot_init() and stack_depot_request_early_init() can be called * regardless of whether CONFIG_STACKDEPOT is enabled and are no-op when this * config is disabled. The save/fetch/print stack depot functions can only be * called from the code that makes sure CONFIG_STACKDEPOT is enabled _and_ * initializes stack depot via one of the ways listed above. */ #ifdef CONFIG_STACKDEPOT int stack_depot_init(void); void __init stack_depot_request_early_init(void); /* Must be only called from mm_init(). */ int __init stack_depot_early_init(void); #else static inline int stack_depot_init(void) { return 0; } static inline void stack_depot_request_early_init(void) { } static inline int stack_depot_early_init(void) { return 0; } #endif /** * stack_depot_save_flags - Save a stack trace to stack depot * * @entries: Pointer to the stack trace * @nr_entries: Number of frames in the stack * @alloc_flags: Allocation GFP flags * @depot_flags: Stack depot flags * * Saves a stack trace from @entries array of size @nr_entries. * * If STACK_DEPOT_FLAG_CAN_ALLOC is set in @depot_flags, stack depot can * replenish the stack pools in case no space is left (allocates using GFP * flags of @alloc_flags). Otherwise, stack depot avoids any allocations and * fails if no space is left to store the stack trace. * * If STACK_DEPOT_FLAG_GET is set in @depot_flags, stack depot will increment * the refcount on the saved stack trace if it already exists in stack depot. * Users of this flag must also call stack_depot_put() when keeping the stack * trace is no longer required to avoid overflowing the refcount. * * If the provided stack trace comes from the interrupt context, only the part * up to the interrupt entry is saved. * * Context: Any context, but setting STACK_DEPOT_FLAG_CAN_ALLOC is required if * alloc_pages() canno