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