| 1 | #ifndef _LTTNG_WRAPPER_VMALLOC_H |
| 2 | #define _LTTNG_WRAPPER_VMALLOC_H |
| 3 | |
| 4 | /* |
| 5 | * wrapper/vmalloc.h |
| 6 | * |
| 7 | * wrapper around vmalloc_sync_all. Using KALLSYMS to get its address when |
| 8 | * available, else we need to have a kernel that exports this function to GPL |
| 9 | * modules. |
| 10 | * |
| 11 | * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 12 | * |
| 13 | * This library is free software; you can redistribute it and/or |
| 14 | * modify it under the terms of the GNU Lesser General Public |
| 15 | * License as published by the Free Software Foundation; only |
| 16 | * version 2.1 of the License. |
| 17 | * |
| 18 | * This library is distributed in the hope that it will be useful, |
| 19 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 20 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 21 | * Lesser General Public License for more details. |
| 22 | * |
| 23 | * You should have received a copy of the GNU Lesser General Public |
| 24 | * License along with this library; if not, write to the Free Software |
| 25 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 26 | */ |
| 27 | |
| 28 | #include <linux/version.h> |
| 29 | #include <linux/vmalloc.h> |
| 30 | #include <linux/mm.h> |
| 31 | |
| 32 | #ifdef CONFIG_KALLSYMS |
| 33 | |
| 34 | #include <linux/kallsyms.h> |
| 35 | #include <wrapper/kallsyms.h> |
| 36 | |
| 37 | static inline |
| 38 | void wrapper_vmalloc_sync_all(void) |
| 39 | { |
| 40 | void (*vmalloc_sync_all_sym)(void); |
| 41 | |
| 42 | vmalloc_sync_all_sym = (void *) kallsyms_lookup_funcptr("vmalloc_sync_all"); |
| 43 | if (vmalloc_sync_all_sym) { |
| 44 | vmalloc_sync_all_sym(); |
| 45 | } else { |
| 46 | #ifdef CONFIG_X86 |
| 47 | /* |
| 48 | * Only x86 needs vmalloc_sync_all to make sure LTTng does not |
| 49 | * trigger recursive page faults. |
| 50 | */ |
| 51 | printk_once(KERN_WARNING "LTTng: vmalloc_sync_all symbol lookup failed.\n"); |
| 52 | printk_once(KERN_WARNING "Page fault handler and NMI tracing might trigger faults.\n"); |
| 53 | #endif |
| 54 | } |
| 55 | } |
| 56 | #else |
| 57 | |
| 58 | static inline |
| 59 | void wrapper_vmalloc_sync_all(void) |
| 60 | { |
| 61 | return vmalloc_sync_all(); |
| 62 | } |
| 63 | #endif |
| 64 | |
| 65 | #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,12,0)) |
| 66 | static inline |
| 67 | void *lttng_kvmalloc_node(unsigned long size, gfp_t flags, int node) |
| 68 | { |
| 69 | void *ret; |
| 70 | |
| 71 | ret = kvmalloc_node(size, flags, node); |
| 72 | if (is_vmalloc_addr(ret)) { |
| 73 | /* |
| 74 | * Make sure we don't trigger recursive page faults in the |
| 75 | * tracing fast path. |
| 76 | */ |
| 77 | wrapper_vmalloc_sync_all(); |
| 78 | } |
| 79 | return ret; |
| 80 | } |
| 81 | |
| 82 | static inline |
| 83 | void *lttng_kvzalloc_node(unsigned long size, gfp_t flags, int node) |
| 84 | { |
| 85 | return lttng_kvmalloc_node(size, flags | __GFP_ZERO, node); |
| 86 | } |
| 87 | |
| 88 | static inline |
| 89 | void *lttng_kvmalloc(unsigned long size, gfp_t flags) |
| 90 | { |
| 91 | return lttng_kvmalloc_node(size, flags, NUMA_NO_NODE); |
| 92 | } |
| 93 | |
| 94 | static inline |
| 95 | void *lttng_kvzalloc(unsigned long size, gfp_t flags) |
| 96 | { |
| 97 | return lttng_kvzalloc_node(size, flags, NUMA_NO_NODE); |
| 98 | } |
| 99 | |
| 100 | static inline |
| 101 | void lttng_kvfree(const void *addr) |
| 102 | { |
| 103 | kvfree(addr); |
| 104 | } |
| 105 | |
| 106 | #else |
| 107 | |
| 108 | #include <linux/slab.h> |
| 109 | |
| 110 | /* |
| 111 | * kallsyms wrapper of __vmalloc_node with a fallback to kmalloc_node. |
| 112 | */ |
| 113 | static inline |
| 114 | void *__lttng_vmalloc_node_fallback(unsigned long size, unsigned long align, |
| 115 | gfp_t gfp_mask, pgprot_t prot, int node, void *caller) |
| 116 | { |
| 117 | void *ret; |
| 118 | |
| 119 | #ifdef CONFIG_KALLSYMS |
| 120 | /* |
| 121 | * If we have KALLSYMS, get * __vmalloc_node which is not exported. |
| 122 | */ |
| 123 | void *(*lttng__vmalloc_node)(unsigned long size, unsigned long align, |
| 124 | gfp_t gfp_mask, pgprot_t prot, int node, void *caller); |
| 125 | |
| 126 | lttng__vmalloc_node = (void *) kallsyms_lookup_funcptr("__vmalloc_node"); |
| 127 | ret = lttng__vmalloc_node(size, align, gfp_mask, prot, node, caller); |
| 128 | #else |
| 129 | /* |
| 130 | * If we don't have KALLSYMS, fallback to kmalloc_node. |
| 131 | */ |
| 132 | ret = kmalloc_node(size, flags, node); |
| 133 | #endif |
| 134 | |
| 135 | return ret; |
| 136 | } |
| 137 | |
| 138 | /** |
| 139 | * lttng_kvmalloc_node - attempt to allocate physically contiguous memory, but upon |
| 140 | * failure, fall back to non-contiguous (vmalloc) allocation. |
| 141 | * @size: size of the request. |
| 142 | * @flags: gfp mask for the allocation - must be compatible with GFP_KERNEL. |
| 143 | * |
| 144 | * Uses kmalloc to get the memory but if the allocation fails then falls back |
| 145 | * to the vmalloc allocator. Use lttng_kvfree to free the memory. |
| 146 | * |
| 147 | * Reclaim modifiers - __GFP_NORETRY, __GFP_REPEAT and __GFP_NOFAIL are not supported |
| 148 | */ |
| 149 | static inline |
| 150 | void *lttng_kvmalloc_node(unsigned long size, gfp_t flags, int node) |
| 151 | { |
| 152 | void *ret; |
| 153 | |
| 154 | /* |
| 155 | * vmalloc uses GFP_KERNEL for some internal allocations (e.g page tables) |
| 156 | * so the given set of flags has to be compatible. |
| 157 | */ |
| 158 | WARN_ON_ONCE((flags & GFP_KERNEL) != GFP_KERNEL); |
| 159 | |
| 160 | /* |
| 161 | * If the allocation fits in a single page, do not fallback. |
| 162 | */ |
| 163 | if (size <= PAGE_SIZE) { |
| 164 | return kmalloc_node(size, flags, node); |
| 165 | } |
| 166 | |
| 167 | /* |
| 168 | * Make sure that larger requests are not too disruptive - no OOM |
| 169 | * killer and no allocation failure warnings as we have a fallback |
| 170 | */ |
| 171 | ret = kmalloc_node(size, flags | __GFP_NOWARN | __GFP_NORETRY, node); |
| 172 | if (!ret) { |
| 173 | if (node == NUMA_NO_NODE) { |
| 174 | /* |
| 175 | * If no node was specified, use __vmalloc which is |
| 176 | * always exported. |
| 177 | */ |
| 178 | ret = __vmalloc(size, flags | __GFP_HIGHMEM, PAGE_KERNEL); |
| 179 | } else { |
| 180 | /* |
| 181 | * Otherwise, we need to select a node but __vmalloc_node |
| 182 | * is not exported, use this fallback wrapper which uses |
| 183 | * kallsyms if available or falls back to kmalloc_node. |
| 184 | */ |
| 185 | ret = __lttng_vmalloc_node_fallback(size, 1, |
| 186 | flags | __GFP_HIGHMEM, PAGE_KERNEL, node, |
| 187 | __builtin_return_address(0)); |
| 188 | } |
| 189 | |
| 190 | /* |
| 191 | * Make sure we don't trigger recursive page faults in the |
| 192 | * tracing fast path. |
| 193 | */ |
| 194 | wrapper_vmalloc_sync_all(); |
| 195 | } |
| 196 | return ret; |
| 197 | } |
| 198 | |
| 199 | static inline |
| 200 | void *lttng_kvzalloc_node(unsigned long size, gfp_t flags, int node) |
| 201 | { |
| 202 | return lttng_kvmalloc_node(size, flags | __GFP_ZERO, node); |
| 203 | } |
| 204 | |
| 205 | static inline |
| 206 | void *lttng_kvmalloc(unsigned long size, gfp_t flags) |
| 207 | { |
| 208 | return lttng_kvmalloc_node(size, flags, NUMA_NO_NODE); |
| 209 | } |
| 210 | |
| 211 | static inline |
| 212 | void *lttng_kvzalloc(unsigned long size, gfp_t flags) |
| 213 | { |
| 214 | return lttng_kvzalloc_node(size, flags, NUMA_NO_NODE); |
| 215 | } |
| 216 | |
| 217 | static inline |
| 218 | void lttng_kvfree(const void *addr) |
| 219 | { |
| 220 | if (is_vmalloc_addr(addr)) { |
| 221 | vfree(addr); |
| 222 | } else { |
| 223 | kfree(addr); |
| 224 | } |
| 225 | } |
| 226 | #endif |
| 227 | |
| 228 | #endif /* _LTTNG_WRAPPER_VMALLOC_H */ |