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 #else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,6,0)) */
  68
  69 /*
  70  * Map vmalloc_sync_mappings to vmalloc_sync_all() on kernels before 5.7.
  71  */
  72 static inline
  73 void wrapper_vmalloc_sync_mappings(void)
  74 {
  75         void (*vmalloc_sync_all_sym)(void);
  76
  77         vmalloc_sync_all_sym = (void *) kallsyms_lookup_funcptr("vmalloc_sync_all");
  78         if (vmalloc_sync_all_sym) {
  79                 vmalloc_sync_all_sym();
  80         } else {
  81 #ifdef CONFIG_X86
  82                 /*
  83                  * Only x86 needs vmalloc_sync_all to make sure LTTng does not
  84                  * trigger recursive page faults.
  85                  */
  86                 printk_once(KERN_WARNING "LTTng: vmalloc_sync_all symbol lookup failed.\n");
  87                 printk_once(KERN_WARNING "Page fault handler and NMI tracing might trigger faults.\n");
  88 #endif
  89         }
  90 }
  91
  92 #endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,6,0)) */
  93
  94 #else
  95
  96 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,6,0) \
  97   || LTTNG_KERNEL_RANGE(5,5,12, 5,6,0)            \
  98   || LTTNG_KERNEL_RANGE(5,4,28, 5,5,0)            \
  99   || LTTNG_KERNEL_RANGE(5,2,37, 5,3,0)            \
 100   || LTTNG_KERNEL_RANGE(4,19,113, 4,20,0)         \
 101   || LTTNG_KERNEL_RANGE(4,14,175, 4,15,0)         \
 102   || LTTNG_KERNEL_RANGE(4,9,218, 4,10,0)          \
 103   || LTTNG_KERNEL_RANGE(4,4,218, 4,5,0))          \
 104   || LTTNG_UBUNTU_KERNEL_RANGE(4,15,18,97, 4,18,0,0) \
 105   || LTTNG_UBUNTU_KERNEL_RANGE(5,0,21,48, 5,1,0,0)   \
 106   || LTTNG_UBUNTU_KERNEL_RANGE(5,3,18,52, 5,4,0,0)
 107
 108 static inline
 109 void wrapper_vmalloc_sync_mappings(void)
 110 {
 111         return vmalloc_sync_mappings();
 112 }
 113
 114 #else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,6,0)) */
 115
 116 static inline
 117 void wrapper_vmalloc_sync_mappings(void)
 118 {
 119         return vmalloc_sync_all();
 120 }
 121
 122 #endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,6,0)) */
 123
 124 #endif
 125
 126 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,12,0))
 127 static inline
 128 void *lttng_kvmalloc_node(unsigned long size, gfp_t flags, int node)
 129 {
 130         void *ret;
 131
 132         ret = kvmalloc_node(size, flags, node);
 133         if (is_vmalloc_addr(ret)) {
 134                 /*
 135                  * Make sure we don't trigger recursive page faults in the
 136                  * tracing fast path.
 137                  */
 138                 wrapper_vmalloc_sync_mappings();
 139         }
 140         return ret;
 141 }
 142
 143 static inline
 144 void *lttng_kvzalloc_node(unsigned long size, gfp_t flags, int node)
 145 {
 146         return lttng_kvmalloc_node(size, flags | __GFP_ZERO, node);
 147 }
 148
 149 static inline
 150 void *lttng_kvmalloc(unsigned long size, gfp_t flags)
 151 {
 152         return lttng_kvmalloc_node(size, flags, NUMA_NO_NODE);
 153 }
 154
 155 static inline
 156 void *lttng_kvzalloc(unsigned long size, gfp_t flags)
 157 {
 158         return lttng_kvzalloc_node(size, flags, NUMA_NO_NODE);
 159 }
 160
 161 static inline
 162 void lttng_kvfree(const void *addr)
 163 {
 164         kvfree(addr);
 165 }
 166
 167 #else
 168
 169 #include <linux/slab.h>
 170
 171 static inline
 172 void print_vmalloc_node_range_warning(void)
 173 {
 174         printk_once(KERN_WARNING "LTTng: __vmalloc_node_range symbol lookup failed.\n");
 175         printk_once(KERN_WARNING "Tracer performance will be degraded on NUMA systems.\n");
 176         printk_once(KERN_WARNING "Please rebuild your kernel with CONFIG_KALLSYMS enabled.\n");
 177 }
 178
 179 /*
 180  * kallsyms wrapper of __vmalloc_node with a fallback to kmalloc_node.
 181  */
 182 static inline
 183 void *__lttng_vmalloc_node_range(unsigned long size, unsigned long align,
 184                         unsigned long start, unsigned long end, gfp_t gfp_mask,
 185                         pgprot_t prot, unsigned long vm_flags, int node,
 186                         const void *caller)
 187 {
 188 #ifdef CONFIG_KALLSYMS
 189         /*
 190          * If we have KALLSYMS, get * __vmalloc_node_range which is not exported.
 191          */
 192         void *(*lttng__vmalloc_node_range)(unsigned long size, unsigned long align,
 193                         unsigned long start, unsigned long end, gfp_t gfp_mask,
 194                         pgprot_t prot, unsigned long vm_flags, int node,
 195                         const void *caller);
 196
 197         lttng__vmalloc_node_range = (void *) kallsyms_lookup_funcptr("__vmalloc_node_range");
 198         if (lttng__vmalloc_node_range)
 199                 return lttng__vmalloc_node_range(size, align, start, end, gfp_mask, prot,
 200                                 vm_flags, node, caller);
 201 #endif
 202         if (node != NUMA_NO_NODE)
 203                 print_vmalloc_node_range_warning();
 204         return __vmalloc(size, gfp_mask, prot);
 205 }
 206
 207 /**
 208  * lttng_kvmalloc_node - attempt to allocate physically contiguous memory, but upon
 209  * failure, fall back to non-contiguous (vmalloc) allocation.
 210  * @size: size of the request.
 211  * @flags: gfp mask for the allocation - must be compatible with GFP_KERNEL.
 212  *
 213  * Uses kmalloc to get the memory but if the allocation fails then falls back
 214  * to the vmalloc allocator. Use lttng_kvfree to free the memory.
 215  *
 216  * Reclaim modifiers - __GFP_NORETRY, __GFP_REPEAT and __GFP_NOFAIL are not supported
 217  */
 218 static inline
 219 void *lttng_kvmalloc_node(unsigned long size, gfp_t flags, int node)
 220 {
 221         void *ret;
 222
 223         /*
 224          * vmalloc uses GFP_KERNEL for some internal allocations (e.g page tables)
 225          * so the given set of flags has to be compatible.
 226          */
 227         WARN_ON_ONCE((flags & GFP_KERNEL) != GFP_KERNEL);
 228
 229         /*
 230          * If the allocation fits in a single page, do not fallback.
 231          */
 232         if (size <= PAGE_SIZE) {
 233                 return kmalloc_node(size, flags, node);
 234         }
 235
 236         /*
 237          * Make sure that larger requests are not too disruptive - no OOM
 238          * killer and no allocation failure warnings as we have a fallback
 239          */
 240         ret = kmalloc_node(size, flags | __GFP_NOWARN | __GFP_NORETRY, node);
 241         if (!ret) {
 242                 ret = __lttng_vmalloc_node_range(size, 1,
 243                                 VMALLOC_START, VMALLOC_END,
 244                                 flags | __GFP_HIGHMEM, PAGE_KERNEL, 0,
 245                                 node, __builtin_return_address(0));
 246                 /*
 247                  * Make sure we don't trigger recursive page faults in the
 248                  * tracing fast path.
 249                  */
 250                 wrapper_vmalloc_sync_mappings();
 251         }
 252         return ret;
 253 }
 254
 255 static inline
 256 void *lttng_kvzalloc_node(unsigned long size, gfp_t flags, int node)
 257 {
 258         return lttng_kvmalloc_node(size, flags | __GFP_ZERO, node);
 259 }
 260
 261 static inline
 262 void *lttng_kvmalloc(unsigned long size, gfp_t flags)
 263 {
 264         return lttng_kvmalloc_node(size, flags, NUMA_NO_NODE);
 265 }
 266
 267 static inline
 268 void *lttng_kvzalloc(unsigned long size, gfp_t flags)
 269 {
 270         return lttng_kvzalloc_node(size, flags, NUMA_NO_NODE);
 271 }
 272
 273 static inline
 274 void lttng_kvfree(const void *addr)
 275 {
 276         if (is_vmalloc_addr(addr)) {
 277                 vfree(addr);
 278         } else {
 279                 kfree(addr);
 280         }
 281 }
 282 #endif
 283
 284 #endif /* _LTTNG_WRAPPER_VMALLOC_H */