projects / lttng-modules.git / blame
| Commit | Line | Data |
|---|---|---|
| 9f36eaed MJ |
1 | /* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1) |
| 2 | * | |
| 42d9070d AG |
3 | * wrapper/writeback.h |
| 4 | * | |
| 5 | * wrapper around global_dirty_limit read. Using KALLSYMS with KALLSYMS_ALL | |
| 6 | * to get its address when available, else we need to have a kernel that | |
| 7 | * exports this variable to GPL modules. | |
| 8 | * | |
| 9 | * Copyright (C) 2013 Mentor Graphics Corp. | |
| 42d9070d AG |
10 | */ |
| 11 | ||
| 9f36eaed MJ |
12 | #ifndef _LTTNG_WRAPPER_WRITEBACK_H |
| 13 | #define _LTTNG_WRAPPER_WRITEBACK_H | |
| 14 | ||
| 6284ae7c | 15 | #include <lttng-kernel-version.h> |
| 42d9070d | 16 | |
| 6284ae7c | 17 | #ifdef CONFIG_KALLSYMS_ALL |
| 42d9070d | 18 | #include <linux/kallsyms.h> |
| 5a2f5e92 | 19 | #include <wrapper/kallsyms.h> |
| 42d9070d | 20 | |
| 6284ae7c MJ |
21 | |
| 22 | ||
| 23 | #if LINUX_VERSION_CODE >= KERNEL_VERSION(4,2,0) | |
| 24 | ||
| 25 | static struct wb_domain *global_wb_domain_sym; | |
| 26 | ||
| 27 | static inline | |
| 28 | unsigned long wrapper_global_dirty_limit(void) | |
| 29 | { | |
| 30 | if (!global_wb_domain_sym) | |
| 31 | global_wb_domain_sym = | |
| 32 | (void *) kallsyms_lookup_dataptr("global_wb_domain"); | |
| 33 | if (global_wb_domain_sym) { | |
| 34 | return global_wb_domain_sym->dirty_limit; | |
| 35 | } else { | |
| 36 | printk_once(KERN_WARNING "LTTng: global_wb_domain symbol lookup failed.\n"); | |
| 37 | return 0; | |
| 38 | } | |
| 39 | } | |
| 60c64030 MJ |
40 | |
| 41 | /* | |
| 42 | * Canary function to check for 'global_wb_domain' at compile time. | |
| 43 | * | |
| 44 | * From 'include/linux/writeback.h': | |
| 45 | * | |
| 46 | * extern struct wb_domain global_wb_domain; | |
| 47 | */ | |
| 48 | static inline | |
| 49 | unsigned long __canary__global_wb_domain(void) | |
| 50 | { | |
| 51 | return global_wb_domain.dirty_limit; | |
| 52 | } | |
| 53 | ||
| 6284ae7c MJ |
54 | #else |
| 55 | ||
| 42d9070d AG |
56 | static unsigned long *global_dirty_limit_sym; |
| 57 | ||
| 58 | static inline | |
| 59 | unsigned long wrapper_global_dirty_limit(void) | |
| 60 | { | |
| 61 | if (!global_dirty_limit_sym) | |
| 62 | global_dirty_limit_sym = | |
| 63 | (void *) kallsyms_lookup_dataptr("global_dirty_limit"); | |
| 64 | if (global_dirty_limit_sym) { | |
| 65 | return *global_dirty_limit_sym; | |
| 66 | } else { | |
| e36de50d | 67 | printk_once(KERN_WARNING "LTTng: global_dirty_limit symbol lookup failed.\n"); |
| 42d9070d AG |
68 | return 0; |
| 69 | } | |
| 70 | } | |
| 60c64030 MJ |
71 | |
| 72 | /* | |
| 73 | * Canary function to check for 'global_dirty_limit' at compile time. | |
| 74 | * | |
| 75 | * From 'include/linux/writeback.h': | |
| 76 | * | |
| 77 | * extern unsigned long global_dirty_limit; | |
| 78 | */ | |
| 79 | static inline | |
| 80 | unsigned long __canary__global_dirty_limit(void) | |
| 81 | { | |
| 82 | return global_dirty_limit; | |
| 83 | } | |
| 84 | ||
| 6284ae7c | 85 | #endif |
| 42d9070d | 86 | |
| 6284ae7c | 87 | #else /* CONFIG_KALLSYMS_ALL */ |
| 42d9070d AG |
88 | |
| 89 | #include <linux/writeback.h> | |
| 90 | ||
| 91 | static inline | |
| 92 | unsigned long wrapper_global_dirty_limit(void) | |
| 93 | { | |
| 94 | return global_dirty_limit; | |
| 95 | } | |
| 96 | ||
| 97 | #endif | |
| 98 | ||
| 99 | #endif /* _LTTNG_WRAPPER_WRITEBACK_H */ |