include/wrapper/vmalloc.h

   1 /* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
   2  *
   3  * wrapper/vmalloc.h
   4  *
   5  * wrapper around vmalloc_sync_all. Using KALLSYMS to get its address when
   6  * available, else we need to have a kernel that exports this function to GPL
   7  * modules.
   8  *
   9  * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  10  */
  11
  12 #ifndef _LTTNG_WRAPPER_VMALLOC_H
  13 #define _LTTNG_WRAPPER_VMALLOC_H
  14
  15 #include <lttng/kernel-version.h>
  16 #include <linux/vmalloc.h>
  17 #include <linux/slab.h>
  18 #include <linux/mm.h>
  19
  20 #ifdef CONFIG_KALLSYMS
  21
  22 #include <linux/kallsyms.h>
  23 #include <wrapper/kallsyms.h>
  24 #include <lttng/kernel-version.h>
  25
  26 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,8,0))
  27
  28 /*
  29  * wrapper_vmalloc_sync_mappings was removed in v5.8, the vmalloc mappings
  30  * are now synchronized when they are created or torn down.
  31  */
  32 static inline
  33 void wrapper_vmalloc_sync_mappings(void)
  34 {}
  35
  36 #elif (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,6,0) \
  37   || LTTNG_KERNEL_RANGE(5,5,12, 5,6,0)            \
  38   || LTTNG_KERNEL_RANGE(5,4,28, 5,5,0)            \
  39   || LTTNG_KERNEL_RANGE(5,2,37, 5,3,0)            \
  40   || LTTNG_KERNEL_RANGE(4,19,113, 4,20,0)         \
  41   || LTTNG_KERNEL_RANGE(4,14,175, 4,15,0)         \
  42   || LTTNG_KERNEL_RANGE(4,9,218, 4,10,0)          \
  43   || LTTNG_KERNEL_RANGE(4,4,218, 4,5,0)           \
  44   || LTTNG_UBUNTU_KERNEL_RANGE(4,15,18,97, 4,16,0,0) \
  45   || LTTNG_UBUNTU_KERNEL_RANGE(5,0,21,48, 5,1,0,0)   \
  46   || LTTNG_UBUNTU_KERNEL_RANGE(5,3,18,52, 5,4,0,0)   \
  47   || LTTNG_RHEL_KERNEL_RANGE(4,18,0,240,0,0, 4,19,0,0,0,0))
  48
  49 static inline
  50 void wrapper_vmalloc_sync_mappings(void)
  51 {
  52         void (*vmalloc_sync_mappings_sym)(void);
  53
  54         vmalloc_sync_mappings_sym = (void *) kallsyms_lookup_funcptr("vmalloc_sync_mappings");
  55         if (vmalloc_sync_mappings_sym) {
  56                 vmalloc_sync_mappings_sym();
  57         } else {
  58 #ifdef CONFIG_X86
  59                 /*
  60                  * Only x86 needs vmalloc_sync_mappings to make sure LTTng does not
  61                  * trigger recursive page faults.
  62                  */
  63                 printk_once(KERN_WARNING "LTTng: vmalloc_sync_mappings symbol lookup failed.\n");
  64                 printk_once(KERN_WARNING "LTTng: Page fault handler and NMI tracing might trigger faults.\n");
  65 #endif
  66         }
  67 }
  68
  69 /*
  70  * Canary function to check for 'vmalloc_sync_mappings()' at compile time.
  71  *
  72  * From 'include/linux/vmalloc.h':
  73  *
  74  *   void vmalloc_sync_mappings(void);
  75  */
  76 static inline
  77 void __canary__vmalloc_sync_mappings(void)
  78 {
  79         vmalloc_sync_mappings();
  80 }
  81
  82 #else /* #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,6,0)) */
  83
  84 /*
  85  * Map vmalloc_sync_mappings to vmalloc_sync_all() on kernels before 5.6.
  86  */
  87 static inline
  88 void wrapper_vmalloc_sync_mappings(void)
  89 {
  90         void (*vmalloc_sync_all_sym)(void);
  91
  92         vmalloc_sync_all_sym = (void *) kallsyms_lookup_funcptr("vmalloc_sync_all");
  93         if (vmalloc_sync_all_sym) {
  94                 vmalloc_sync_all_sym();
  95         } else {
  96 #ifdef CONFIG_X86
  97                 /*
  98                  * Only x86 needs vmalloc_sync_all to make sure LTTng does not
  99                  * trigger recursive page faults.
 100                  */
 101                 printk_once(KERN_WARNING "LTTng: vmalloc_sync_all symbol lookup failed.\n");
 102                 printk_once(KERN_WARNING "LTTng: Page fault handler and NMI tracing might trigger faults.\n");
 103 #endif
 104         }
 105 }
 106
 107 /*
 108  * Canary function to check for 'vmalloc_sync_all()' at compile time.
 109  *
 110  * From 'include/linux/vmalloc.h':
 111  *
 112  *   void vmalloc_sync_all(void);
 113  */
 114 static inline
 115 void __canary__vmalloc_sync_all(void)
 116 {
 117         vmalloc_sync_all();
 118 }
 119
 120 #endif /* #else #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,6,0)) */
 121
 122 #else /* CONFIG_KALLSYMS */
 123
 124 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,8,0))
 125
 126 /*
 127  * wrapper_vmalloc_sync_mappings was removed in v5.8, the vmalloc mappings
 128  * are now synchronized when they are created or torn down.
 129  */
 130 static inline
 131 void wrapper_vmalloc_sync_mappings(void)
 132 {}
 133
 134 #elif (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,6,0) \
 135   || LTTNG_KERNEL_RANGE(5,5,12, 5,6,0)            \
 136   || LTTNG_KERNEL_RANGE(5,4,28, 5,5,0)            \
 137   || LTTNG_KERNEL_RANGE(5,2,37, 5,3,0)            \
 138   || LTTNG_KERNEL_RANGE(4,19,113, 4,20,0)         \
 139   || LTTNG_KERNEL_RANGE(4,14,175, 4,15,0)         \
 140   || LTTNG_KERNEL_RANGE(4,9,218, 4,10,0)          \
 141   || LTTNG_KERNEL_RANGE(4,4,218, 4,5,0))          \
 142   || LTTNG_UBUNTU_KERNEL_RANGE(4,15,18,97, 4,18,0,0) \
 143   || LTTNG_UBUNTU_KERNEL_RANGE(5,0,21,48, 5,1,0,0)   \
 144   || LTTNG_UBUNTU_KERNEL_RANGE(5,3,18,52, 5,4,0,0)
 145
 146 static inline
 147 void wrapper_vmalloc_sync_mappings(void)
 148 {
 149         return vmalloc_sync_mappings();
 150 }
 151
 152 #else /* #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,6,0)) */
 153
 154 static inline
 155 void wrapper_vmalloc_sync_mappings(void)
 156 {
 157         return vmalloc_sync_all();
 158 }
 159
 160 #endif /* #else #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,6,0)) */
 161
 162 #endif /* CONFIG_KALLSYMS */
 163
 164 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,12,0))
 165 static inline
 166 void *lttng_kvmalloc_node(unsigned long size, gfp_t flags, int node)
 167 {
 168         void *ret;
 169
 170         ret = kvmalloc_node(size, flags, node);
 171         if (is_vmalloc_addr(ret)) {
 172                 /*
 173                  * Make sure we don't trigger recursive page faults in the
 174                  * tracing fast path.
 175                  */
 176                 wrapper_vmalloc_sync_mappings();
 177         }
 178         return ret;
 179 }
 180
 181 static inline
 182 void *lttng_kvzalloc_node(unsigned long size, gfp_t flags, int node)
 183 {
 184         return lttng_kvmalloc_node(size, flags | __GFP_ZERO, node);
 185 }
 186
 187 static inline
 188 void *lttng_kvmalloc(unsigned long size, gfp_t flags)
 189 {
 190         return lttng_kvmalloc_node(size, flags, NUMA_NO_NODE);
 191 }
 192
 193 static inline
 194 void *lttng_kvzalloc(unsigned long size, gfp_t flags)
 195 {
 196         return lttng_kvzalloc_node(size, flags, NUMA_NO_NODE);
 197 }
 198
 199 static inline
 200 void lttng_kvfree(const void *addr)
 201 {
 202         kvfree(addr);
 203 }
 204
 205 #else /* >= LTTNG_KERNEL_VERSION(4,12,0) */
 206
 207 #include <linux/slab.h>
 208
 209 static inline
 210 void print_vmalloc_node_range_warning(void)
 211 {
 212         printk_once(KERN_WARNING "LTTng: __vmalloc_node_range symbol lookup failed.\n");
 213         printk_once(KERN_WARNING "LTTng: Tracer performance will be degraded on NUMA systems.\n");
 214         printk_once(KERN_WARNING "LTTng: Please rebuild your kernel with CONFIG_KALLSYMS enabled.\n");
 215 }
 216
 217 /*
 218  * kallsyms wrapper of __vmalloc_node with a fallback to kmalloc_node.
 219  */
 220 static inline
 221 void *__lttng_vmalloc_node_range(unsigned long size, unsigned long align,
 222                         unsigned long start, unsigned long end, gfp_t gfp_mask,
 223                         pgprot_t prot, unsigned long vm_flags, int node,
 224                         const void *caller)
 225 {
 226 #ifdef CONFIG_KALLSYMS
 227         /*
 228          * If we have KALLSYMS, get * __vmalloc_node_range which is not exported.
 229          */
 230         void *(*lttng__vmalloc_node_range)(unsigned long size, unsigned long align,
 231                         unsigned long start, unsigned long end, gfp_t gfp_mask,
 232                         pgprot_t prot, unsigned long vm_flags, int node,
 233                         const void *caller);
 234
 235         lttng__vmalloc_node_range = (void *) kallsyms_lookup_funcptr("__vmalloc_node_range");
 236         if (lttng__vmalloc_node_range)
 237                 return lttng__vmalloc_node_range(size, align, start, end, gfp_mask, prot,
 238                                 vm_flags, node, caller);
 239 #endif
 240         if (node != NUMA_NO_NODE)
 241                 print_vmalloc_node_range_warning();
 242         return __vmalloc(size, gfp_mask, prot);
 243 }
 244
 245 /*
 246  * Canary function to check for '__vmalloc_node_range()' at compile time.
 247  *
 248  * From 'include/linux/vmalloc.h':
 249  *
 250  *   extern void *__vmalloc_node_range(unsigned long size, unsigned long align,
 251  *                           unsigned long start, unsigned long end, gfp_t gfp_mask,
 252  *                           pgprot_t prot, unsigned long vm_flags, int node,
 253  *                           const void *caller);
 254  */
 255 static inline
 256 void *__canary____lttng_vmalloc_node_range(unsigned long size, unsigned long align,
 257                         unsigned long start, unsigned long end, gfp_t gfp_mask,
 258                         pgprot_t prot, unsigned long vm_flags, int node,
 259                         const void *caller)
 260 {
 261         return __vmalloc_node_range(size, align, start, end, gfp_mask, prot,
 262                         vm_flags, node, caller);
 263 }
 264
 265 /**
 266  * lttng_kvmalloc_node - attempt to allocate physically contiguous memory, but upon
 267  * failure, fall back to non-contiguous (vmalloc) allocation.
 268  * @size: size of the request.
 269  * @flags: gfp mask for the allocation - must be compatible with GFP_KERNEL.
 270  *
 271  * Uses kmalloc to get the memory but if the allocation fails then falls back
 272  * to the vmalloc allocator. Use lttng_kvfree to free the memory.
 273  *
 274  * Reclaim modifiers - __GFP_NORETRY, __GFP_REPEAT and __GFP_NOFAIL are not supported
 275  */
 276 static inline
 277 void *lttng_kvmalloc_node(unsigned long size, gfp_t flags, int node)
 278 {
 279         void *ret;
 280
 281         /*
 282          * vmalloc uses GFP_KERNEL for some internal allocations (e.g page tables)
 283          * so the given set of flags has to be compatible.
 284          */
 285         WARN_ON_ONCE((flags & GFP_KERNEL) != GFP_KERNEL);
 286
 287         /*
 288          * If the allocation fits in a single page, do not fallback.
 289          */
 290         if (size <= PAGE_SIZE) {
 291                 return kmalloc_node(size, flags, node);
 292         }
 293
 294         /*
 295          * Make sure that larger requests are not too disruptive - no OOM
 296          * killer and no allocation failure warnings as we have a fallback
 297          */
 298         ret = kmalloc_node(size, flags | __GFP_NOWARN | __GFP_NORETRY, node);
 299         if (!ret) {
 300                 ret = __lttng_vmalloc_node_range(size, 1,
 301                                 VMALLOC_START, VMALLOC_END,
 302                                 flags | __GFP_HIGHMEM, PAGE_KERNEL, 0,
 303                                 node, __builtin_return_address(0));
 304                 /*
 305                  * Make sure we don't trigger recursive page faults in the
 306                  * tracing fast path.
 307                  */
 308                 wrapper_vmalloc_sync_mappings();
 309         }
 310         return ret;
 311 }
 312
 313 static inline
 314 void *lttng_kvzalloc_node(unsigned long size, gfp_t flags, int node)
 315 {
 316         return lttng_kvmalloc_node(size, flags | __GFP_ZERO, node);
 317 }
 318
 319 static inline
 320 void *lttng_kvmalloc(unsigned long size, gfp_t flags)
 321 {
 322         return lttng_kvmalloc_node(size, flags, NUMA_NO_NODE);
 323 }
 324
 325 static inline
 326 void *lttng_kvzalloc(unsigned long size, gfp_t flags)
 327 {
 328         return lttng_kvzalloc_node(size, flags, NUMA_NO_NODE);
 329 }
 330
 331 static inline
 332 void lttng_kvfree(const void *addr)
 333 {
 334         if (is_vmalloc_addr(addr)) {
 335                 vfree(addr);
 336         } else {
 337                 kfree(addr);
 338         }
 339 }
 340 #endif /* >= LTTNG_KERNEL_VERSION(4,12,0) */
 341
 342 #endif /* _LTTNG_WRAPPER_VMALLOC_H */