| 1 |
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| 2 | |
| 3 | * A generic stack depot implementation
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| 4 | *
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| 5 | * Author: Alexander Potapenko <[email protected]>
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| 6 | * Copyright (C) 2016 Google, Inc.
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| 7 | *
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| 8 | * Based on code by Dmitry Chernenkov.
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| 9 |
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| 10 |
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| 11 | #ifndef _LINUX_STACKDEPOT_H
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| 12 | #define _LINUX_STACKDEPOT_H
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| 13 |
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| 14 | #include <linux/gfp.h>
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| 15 |
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| 16 | typedef u32 depot_stack_handle_t;
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| 17 | |
| 18 | * Number of bits in the handle that stack depot doesn't use. Users may store
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| 19 | * information in them.
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| 20 |
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| 21 | #define STACK_DEPOT_EXTRA_BITS 5
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| 22 |
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| 23 | depot_stack_handle_t __stack_depot_save(unsigned long *entries,
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| 24 | unsigned int nr_entries,
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| 25 | unsigned int extra_bits,
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| 26 | gfp_t gfp_flags, bool can_alloc);
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| 27 |
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| 28 | |
| 29 | * Every user of stack depot has to call stack_depot_init() during its own init
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| 30 | * when it's decided that it will be calling stack_depot_save() later. This is
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| 31 | * recommended for e.g. modules initialized later in the boot process, when
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| 32 | * slab_is_available() is true.
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| 33 | *
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| 34 | * The alternative is to select STACKDEPOT_ALWAYS_INIT to have stack depot
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| 35 | * enabled as part of mm_init(), for subsystems where it's known at compile time
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| 36 | * that stack depot will be used.
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| 37 | *
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| 38 | * Another alternative is to call stack_depot_want_early_init(), when the
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| 39 | * decision to use stack depot is taken e.g. when evaluating kernel boot
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| 40 | * parameters, which precedes the enablement point in mm_init().
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| 41 | *
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| 42 | * stack_depot_init() and stack_depot_want_early_init() can be called regardless
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| 43 | * of CONFIG_STACKDEPOT and are no-op when disabled. The actual save/fetch/print
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| 44 | * functions should only be called from code that makes sure CONFIG_STACKDEPOT
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| 45 | * is enabled.
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| 46 |
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| 47 | #ifdef CONFIG_STACKDEPOT
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| 48 | int stack_depot_init(void);
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| 49 |
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| 50 | void __init stack_depot_want_early_init(void);
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| 51 |
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| 52 |
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| 53 | int __init stack_depot_early_init(void);
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| 54 | #else
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| 55 | static inline int stack_depot_init(void) { return 0; }
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| 56 |
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| 57 | static inline void stack_depot_want_early_init(void) { }
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| 58 |
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| 59 | static inline int stack_depot_early_init(void) { return 0; }
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| 60 | #endif
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| 61 |
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| 62 | depot_stack_handle_t stack_depot_save(unsigned long *entries,
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| 63 | unsigned int nr_entries, gfp_t gfp_flags);
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| 64 |
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| 65 | unsigned int stack_depot_fetch(depot_stack_handle_t handle,
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| 66 | unsigned long **entries);
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| 67 |
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| 68 | unsigned int stack_depot_get_extra_bits(depot_stack_handle_t handle);
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| 69 |
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| 70 | int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size,
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| 71 | int spaces);
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| 72 |
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| 73 | void stack_depot_print(depot_stack_handle_t stack);
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| 74 |
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| 75 | #endif
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