| 1 | /* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only) |
| 2 | * |
| 3 | * wrapper/genhd.h |
| 4 | * |
| 5 | * wrapper around block layer functions and data structures. Using |
| 6 | * KALLSYMS to get its address when available, else we need to have a |
| 7 | * kernel that exports this function to GPL modules. |
| 8 | * |
| 9 | * Copyright (C) 2011-2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 10 | */ |
| 11 | |
| 12 | #ifndef _LTTNG_WRAPPER_GENHD_H |
| 13 | #define _LTTNG_WRAPPER_GENHD_H |
| 14 | |
| 15 | #include <linux/genhd.h> |
| 16 | #include <lttng/kernel-version.h> |
| 17 | |
| 18 | #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,11,0)) |
| 19 | #define LTTNG_DISK_PART_TYPE struct block_device |
| 20 | #else |
| 21 | #define LTTNG_DISK_PART_TYPE struct hd_struct |
| 22 | #endif |
| 23 | |
| 24 | #ifdef CONFIG_KALLSYMS_ALL |
| 25 | |
| 26 | #include <linux/kallsyms.h> |
| 27 | #include <wrapper/kallsyms.h> |
| 28 | |
| 29 | static inline |
| 30 | struct class *wrapper_get_block_class(void) |
| 31 | { |
| 32 | struct class *ptr_block_class; |
| 33 | |
| 34 | ptr_block_class = (struct class *) kallsyms_lookup_dataptr("block_class"); |
| 35 | if (!ptr_block_class) { |
| 36 | printk_once(KERN_WARNING "LTTng: block_class symbol lookup failed.\n"); |
| 37 | return NULL; |
| 38 | } |
| 39 | return ptr_block_class; |
| 40 | } |
| 41 | |
| 42 | /* |
| 43 | * Canary function to check for 'block_class' at compile time. |
| 44 | * |
| 45 | * From 'include/linux/genhd.h': |
| 46 | * |
| 47 | * extern struct class block_class; |
| 48 | */ |
| 49 | static inline |
| 50 | struct class *__canary__get_block_class(void) |
| 51 | { |
| 52 | return &block_class; |
| 53 | } |
| 54 | |
| 55 | static inline |
| 56 | struct device_type *wrapper_get_disk_type(void) |
| 57 | { |
| 58 | struct device_type *ptr_disk_type; |
| 59 | |
| 60 | ptr_disk_type = (struct device_type *) kallsyms_lookup_dataptr("disk_type"); |
| 61 | if (!ptr_disk_type) { |
| 62 | printk_once(KERN_WARNING "LTTng: disk_type symbol lookup failed.\n"); |
| 63 | return NULL; |
| 64 | } |
| 65 | return ptr_disk_type; |
| 66 | } |
| 67 | |
| 68 | /* |
| 69 | * No canary for 'disk_type', it's only defined in 'block/genhd.c'. |
| 70 | * |
| 71 | * static inline |
| 72 | * struct device_type *__canary__get_disk_type(void) |
| 73 | * { |
| 74 | * return &disk_type; |
| 75 | * } |
| 76 | */ |
| 77 | |
| 78 | #else |
| 79 | |
| 80 | static inline |
| 81 | struct class *wrapper_get_block_class(void) |
| 82 | { |
| 83 | /* |
| 84 | * Symbol block_class is not exported. |
| 85 | * TODO: return &block_class; |
| 86 | */ |
| 87 | /* Feature currently unavailable without KALLSYMS_ALL */ |
| 88 | return NULL; |
| 89 | } |
| 90 | |
| 91 | static inline |
| 92 | struct device_type *wrapper_get_disk_type(void) |
| 93 | { |
| 94 | /* |
| 95 | * Symbol disk_type is not exported. |
| 96 | * TODO: return &disk_type; |
| 97 | */ |
| 98 | /* Feature currently unavailable without KALLSYMS_ALL */ |
| 99 | return NULL; |
| 100 | } |
| 101 | |
| 102 | #endif |
| 103 | |
| 104 | /* |
| 105 | * This wrapper has an 'int' return type instead of the original 'void', to be |
| 106 | * able to report the symbol lookup failure to the caller. |
| 107 | * |
| 108 | * Return 0 on success, -1 on error. |
| 109 | */ |
| 110 | int wrapper_disk_part_iter_init(struct disk_part_iter *piter, struct gendisk *disk, |
| 111 | unsigned int flags); |
| 112 | LTTNG_DISK_PART_TYPE *wrapper_disk_part_iter_next(struct disk_part_iter *piter); |
| 113 | void wrapper_disk_part_iter_exit(struct disk_part_iter *piter); |
| 114 | |
| 115 | /* |
| 116 | * Canary function to check for 'disk_part_iter_init()' at compile time. |
| 117 | * |
| 118 | * From 'include/linux/genhd.h': |
| 119 | * |
| 120 | * extern void disk_part_iter_init(struct disk_part_iter *piter, |
| 121 | * struct gendisk *disk, unsigned int flags); |
| 122 | * |
| 123 | */ |
| 124 | static inline |
| 125 | void __canary__disk_part_iter_init(struct disk_part_iter *piter, struct gendisk *disk, |
| 126 | unsigned int flags) |
| 127 | { |
| 128 | disk_part_iter_init(piter, disk, flags); |
| 129 | } |
| 130 | |
| 131 | /* |
| 132 | * Canary function to check for 'disk_part_iter_next()' at compile time. |
| 133 | * |
| 134 | * From 'include/linux/genhd.h': |
| 135 | * |
| 136 | * struct block_device *disk_part_iter_next(struct disk_part_iter *piter); |
| 137 | * |
| 138 | */ |
| 139 | static inline |
| 140 | LTTNG_DISK_PART_TYPE *__canary__disk_part_iter_next(struct disk_part_iter *piter) |
| 141 | { |
| 142 | return disk_part_iter_next(piter); |
| 143 | } |
| 144 | |
| 145 | /* |
| 146 | * Canary function to check for 'disk_part_iter_exit()' at compile time. |
| 147 | * |
| 148 | * From 'include/linux/genhd.h': |
| 149 | * |
| 150 | * extern void disk_part_iter_exit(struct disk_part_iter *piter); |
| 151 | * |
| 152 | */ |
| 153 | static inline |
| 154 | void __canary__disk_part_iter_exit(struct disk_part_iter *piter) |
| 155 | { |
| 156 | return disk_part_iter_exit(piter); |
| 157 | } |
| 158 | |
| 159 | #endif /* _LTTNG_WRAPPER_GENHD_H */ |