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(5,6,0) \
  26   || LTTNG_KERNEL_RANGE(5,5,12, 5,6,0)            \
  27   || LTTNG_KERNEL_RANGE(5,4,28, 5,5,0)            \
  28   || LTTNG_KERNEL_RANGE(5,2,37, 5,3,0)            \
  29   || LTTNG_KERNEL_RANGE(4,19,113, 4,20,0)         \
  30   || LTTNG_KERNEL_RANGE(4,14,175, 4,15,0)         \
  31   || LTTNG_KERNEL_RANGE(4,9,218, 4,10,0)          \
  32   || LTTNG_KERNEL_RANGE(4,4,218, 4,5,0))          \
  33   || LTTNG_UBUNTU_KERNEL_RANGE(4,15,18,97, 4,16,0,0) \
  34   || LTTNG_UBUNTU_KERNEL_RANGE(5,0,21,48, 5,1,0,0)   \
  35   || LTTNG_UBUNTU_KERNEL_RANGE(5,3,18,52, 5,4,0,0)
  36
  37 static inline
  38 void wrapper_vmalloc_sync_mappings(void)
  39 {
  40         void (*vmalloc_sync_mappings_sym)(void);
  41
  42         vmalloc_sync_mappings_sym = (void *) kallsyms_lookup_funcptr("vmalloc_sync_mappings");
  43         if (vmalloc_sync_mappings_sym) {
  44                 vmalloc_sync_mappings_sym();
  45         } else {
  46 #ifdef CONFIG_X86
  47                 /*
  48                  * Only x86 needs vmalloc_sync_mappings to make sure LTTng does not
  49                  * trigger recursive page faults.
  50                  */
  51                 printk_once(KERN_WARNING "LTTng: vmalloc_sync_mappings symbol lookup failed.\n");
  52                 printk_once(KERN_WARNING "Page fault handler and NMI tracing might trigger faults.\n");
  53 #endif
  54         }
  55 }
  56
  57 #else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,6,0)) */
  58
  59 /*
  60  * Map vmalloc_sync_mappings to vmalloc_sync_all() on kernels before 5.7.
  61  */
  62 static inline
  63 void wrapper_vmalloc_sync_mappings(void)
  64 {
  65         void (*vmalloc_sync_all_sym)(void);
  66
  67         vmalloc_sync_all_sym = (void *) kallsyms_lookup_funcptr("vmalloc_sync_all");
  68         if (vmalloc_sync_all_sym) {
  69                 vmalloc_sync_all_sym();
  70         } else {
  71 #ifdef CONFIG_X86
  72                 /*
  73                  * Only x86 needs vmalloc_sync_all to make sure LTTng does not
  74                  * trigger recursive page faults.
  75                  */
  76                 printk_once(KERN_WARNING "LTTng: vmalloc_sync_all symbol lookup failed.\n");
  77                 printk_once(KERN_WARNING "Page fault handler and NMI tracing might trigger faults.\n");
  78 #endif
  79         }
  80 }
  81
  82 #endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,6,0)) */
  83
  84 #else
  85
  86 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,6,0) \
  87   || LTTNG_KERNEL_RANGE(5,5,12, 5,6,0)            \
  88   || LTTNG_KERNEL_RANGE(5,4,28, 5,5,0)            \
  89   || LTTNG_KERNEL_RANGE(5,2,37, 5,3,0)            \
  90   || LTTNG_KERNEL_RANGE(4,19,113, 4,20,0)         \
  91   || LTTNG_KERNEL_RANGE(4,14,175, 4,15,0)         \
  92   || LTTNG_KERNEL_RANGE(4,9,218, 4,10,0)          \
  93   || LTTNG_KERNEL_RANGE(4,4,218, 4,5,0))          \
  94   || LTTNG_UBUNTU_KERNEL_RANGE(4,15,18,97, 4,18,0,0) \
  95   || LTTNG_UBUNTU_KERNEL_RANGE(5,0,21,48, 5,1,0,0)   \
  96   || LTTNG_UBUNTU_KERNEL_RANGE(5,3,18,52, 5,4,0,0)
  97
  98 static inline
  99 void wrapper_vmalloc_sync_mappings(void)
 100 {
 101         return vmalloc_sync_mappings();
 102 }
 103
 104 #else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,6,0)) */
 105
 106 static inline
 107 void wrapper_vmalloc_sync_mappings(void)
 108 {
 109         return vmalloc_sync_all();
 110 }
 111
 112 #endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,6,0)) */
 113
 114 #endif
 115
 116 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,12,0))
 117 static inline
 118 void *lttng_kvmalloc_node(unsigned long size, gfp_t flags, int node)
 119 {
 120         void *ret;
 121
 122         ret = kvmalloc_node(size, flags, node);
 123         if (is_vmalloc_addr(ret)) {
 124                 /*
 125                  * Make sure we don't trigger recursive page faults in the
 126                  * tracing fast path.
 127                  */
 128                 wrapper_vmalloc_sync_mappings();
 129         }
 130         return ret;
 131 }
 132
 133 static inline
 134 void *lttng_kvzalloc_node(unsigned long size, gfp_t flags, int node)
 135 {
 136         return lttng_kvmalloc_node(size, flags | __GFP_ZERO, node);
 137 }
 138
 139 static inline
 140 void *lttng_kvmalloc(unsigned long size, gfp_t flags)
 141 {
 142         return lttng_kvmalloc_node(size, flags, NUMA_NO_NODE);
 143 }
 144
 145 static inline
 146 void *lttng_kvzalloc(unsigned long size, gfp_t flags)
 147 {
 148         return lttng_kvzalloc_node(size, flags, NUMA_NO_NODE);
 149 }
 150
 151 static inline
 152 void lttng_kvfree(const void *addr)
 153 {
 154         kvfree(addr);
 155 }
 156
 157 #else
 158
 159 #include <linux/slab.h>
 160
 161 static inline
 162 void print_vmalloc_node_range_warning(void)
 163 {
 164         printk_once(KERN_WARNING "LTTng: __vmalloc_node_range symbol lookup failed.\n");
 165         printk_once(KERN_WARNING "Tracer performance will be degraded on NUMA systems.\n");
 166         printk_once(KERN_WARNING "Please rebuild your kernel with CONFIG_KALLSYMS enabled.\n");
 167 }
 168
 169 /*
 170  * kallsyms wrapper of __vmalloc_node with a fallback to kmalloc_node.
 171  */
 172 static inline
 173 void *__lttng_vmalloc_node_range(unsigned long size, unsigned long align,
 174                         unsigned long start, unsigned long end, gfp_t gfp_mask,
 175                         pgprot_t prot, unsigned long vm_flags, int node,
 176                         const void *caller)
 177 {
 178 #ifdef CONFIG_KALLSYMS
 179         /*
 180          * If we have KALLSYMS, get * __vmalloc_node_range which is not exported.
 181          */
 182         void *(*lttng__vmalloc_node_range)(unsigned long size, unsigned long align,
 183                         unsigned long start, unsigned long end, gfp_t gfp_mask,
 184                         pgprot_t prot, unsigned long vm_flags, int node,
 185                         const void *caller);
 186
 187         lttng__vmalloc_node_range = (void *) kallsyms_lookup_funcptr("__vmalloc_node_range");
 188         if (lttng__vmalloc_node_range)
 189                 return lttng__vmalloc_node_range(size, align, start, end, gfp_mask, prot,
 190                                 vm_flags, node, caller);
 191 #endif
 192         if (node != NUMA_NO_NODE)
 193                 print_vmalloc_node_range_warning();
 194         return __vmalloc(size, gfp_mask, prot);
 195 }
 196
 197 /**
 198  * lttng_kvmalloc_node - attempt to allocate physically contiguous memory, but upon
 199  * failure, fall back to non-contiguous (vmalloc) allocation.
 200  * @size: size of the request.
 201  * @flags: gfp mask for the allocation - must be compatible with GFP_KERNEL.
 202  *
 203  * Uses kmalloc to get the memory but if the allocation fails then falls back
 204  * to the vmalloc allocator. Use lttng_kvfree to free the memory.
 205  *
 206  * Reclaim modifiers - __GFP_NORETRY, __GFP_REPEAT and __GFP_NOFAIL are not supported
 207  */
 208 static inline
 209 void *lttng_kvmalloc_node(unsigned long size, gfp_t flags, int node)
 210 {
 211         void *ret;
 212
 213         /*
 214          * vmalloc uses GFP_KERNEL for some internal allocations (e.g page tables)
 215          * so the given set of flags has to be compatible.
 216          */
 217         WARN_ON_ONCE((flags & GFP_KERNEL) != GFP_KERNEL);
 218
 219         /*
 220          * If the allocation fits in a single page, do not fallback.
 221          */
 222         if (size <= PAGE_SIZE) {
 223                 return kmalloc_node(size, flags, node);
 224         }
 225
 226         /*
 227          * Make sure that larger requests are not too disruptive - no OOM
 228          * killer and no allocation failure warnings as we have a fallback
 229          */
 230         ret = kmalloc_node(size, flags | __GFP_NOWARN | __GFP_NORETRY, node);
 231         if (!ret) {
 232                 ret = __lttng_vmalloc_node_range(size, 1,
 233                                 VMALLOC_START, VMALLOC_END,
 234                                 flags | __GFP_HIGHMEM, PAGE_KERNEL, 0,
 235                                 node, __builtin_return_address(0));
 236                 /*
 237                  * Make sure we don't trigger recursive page faults in the
 238                  * tracing fast path.
 239                  */
 240                 wrapper_vmalloc_sync_mappings();
 241         }
 242         return ret;
 243 }
 244
 245 static inline
 246 void *lttng_kvzalloc_node(unsigned long size, gfp_t flags, int node)
 247 {
 248         return lttng_kvmalloc_node(size, flags | __GFP_ZERO, node);
 249 }
 250
 251 static inline
 252 void *lttng_kvmalloc(unsigned long size, gfp_t flags)
 253 {
 254         return lttng_kvmalloc_node(size, flags, NUMA_NO_NODE);
 255 }
 256
 257 static inline
 258 void *lttng_kvzalloc(unsigned long size, gfp_t flags)
 259 {
 260         return lttng_kvzalloc_node(size, flags, NUMA_NO_NODE);
 261 }
 262
 263 static inline
 264 void lttng_kvfree(const void *addr)
 265 {
 266         if (is_vmalloc_addr(addr)) {
 267                 vfree(addr);
 268         } else {
 269                 kfree(addr);
 270         }
 271 }
 272 #endif
 273
 274 #endif /* _LTTNG_WRAPPER_VMALLOC_H */