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