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