| 1 | /* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1) |
| 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 | |
| 17 | #ifdef CONFIG_KALLSYMS_ALL |
| 18 | |
| 19 | #include <linux/kallsyms.h> |
| 20 | #include <wrapper/kallsyms.h> |
| 21 | |
| 22 | static inline |
| 23 | struct class *wrapper_get_block_class(void) |
| 24 | { |
| 25 | struct class *ptr_block_class; |
| 26 | |
| 27 | ptr_block_class = (struct class *) kallsyms_lookup_dataptr("block_class"); |
| 28 | if (!ptr_block_class) { |
| 29 | printk_once(KERN_WARNING "LTTng: block_class symbol lookup failed.\n"); |
| 30 | return NULL; |
| 31 | } |
| 32 | return ptr_block_class; |
| 33 | } |
| 34 | |
| 35 | /* |
| 36 | * Canary function to check for 'block_class' at compile time. |
| 37 | * |
| 38 | * From 'include/linux/genhd.h': |
| 39 | * |
| 40 | * extern struct class block_class; |
| 41 | */ |
| 42 | static inline |
| 43 | struct class *__canary__get_block_class(void) |
| 44 | { |
| 45 | return &block_class; |
| 46 | } |
| 47 | |
| 48 | static inline |
| 49 | struct device_type *wrapper_get_disk_type(void) |
| 50 | { |
| 51 | struct device_type *ptr_disk_type; |
| 52 | |
| 53 | ptr_disk_type = (struct device_type *) kallsyms_lookup_dataptr("disk_type"); |
| 54 | if (!ptr_disk_type) { |
| 55 | printk_once(KERN_WARNING "LTTng: disk_type symbol lookup failed.\n"); |
| 56 | return NULL; |
| 57 | } |
| 58 | return ptr_disk_type; |
| 59 | } |
| 60 | |
| 61 | /* |
| 62 | * No canary for 'disk_type', it's only defined in 'block/genhd.c'. |
| 63 | * |
| 64 | * static inline |
| 65 | * struct device_type *__canary__get_disk_type(void) |
| 66 | * { |
| 67 | * return &disk_type; |
| 68 | * } |
| 69 | */ |
| 70 | |
| 71 | #else |
| 72 | |
| 73 | static inline |
| 74 | struct class *wrapper_get_block_class(void) |
| 75 | { |
| 76 | /* |
| 77 | * Symbol block_class is not exported. |
| 78 | * TODO: return &block_class; |
| 79 | */ |
| 80 | /* Feature currently unavailable without KALLSYMS_ALL */ |
| 81 | return NULL; |
| 82 | } |
| 83 | |
| 84 | static inline |
| 85 | struct device_type *wrapper_get_disk_type(void) |
| 86 | { |
| 87 | /* |
| 88 | * Symbol disk_type is not exported. |
| 89 | * TODO: return &disk_type; |
| 90 | */ |
| 91 | /* Feature currently unavailable without KALLSYMS_ALL */ |
| 92 | return NULL; |
| 93 | } |
| 94 | |
| 95 | #endif |
| 96 | |
| 97 | #endif /* _LTTNG_WRAPPER_GENHD_H */ |