osfmk/mach/vm_param.h

   1 /*
   2  * Copyright (c) 2000-2006 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
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   6  * This file contains Original Code and/or Modifications of Original Code
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   8  * Version 2.0 (the 'License'). You may not use this file except in
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  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
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  23  * Please see the License for the specific language governing rights and
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  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*
  29  * @OSF_COPYRIGHT@
  30  */
  31 /*
  32  * Mach Operating System
  33  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
  34  * All Rights Reserved.
  35  *
  36  * Permission to use, copy, modify and distribute this software and its
  37  * documentation is hereby granted, provided that both the copyright
  38  * notice and this permission notice appear in all copies of the
  39  * software, derivative works or modified versions, and any portions
  40  * thereof, and that both notices appear in supporting documentation.
  41  *
  42  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  43  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  44  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  45  *
  46  * Carnegie Mellon requests users of this software to return to
  47  *
  48  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  49  *  School of Computer Science
  50  *  Carnegie Mellon University
  51  *  Pittsburgh PA 15213-3890
  52  *
  53  * any improvements or extensions that they make and grant Carnegie Mellon
  54  * the rights to redistribute these changes.
  55  */
  56 /*
  57  */
  58 /*
  59  *      File:   mach/vm_param.h
  60  *      Author: Avadis Tevanian, Jr., Michael Wayne Young
  61  *      Date:   1985
  62  *
  63  *      Machine independent virtual memory parameters.
  64  *
  65  */
  66
  67 #ifndef _MACH_VM_PARAM_H_
  68 #define _MACH_VM_PARAM_H_
  69
  70 #include <mach/machine/vm_param.h>
  71
  72 #ifdef  KERNEL
  73
  74 #ifndef ASSEMBLER
  75 #include <mach/vm_types.h>
  76 #endif  /* ASSEMBLER */
  77
  78 #include <os/base.h>
  79 #include <os/overflow.h>
  80
  81 /*
  82  *      The machine independent pages are refered to as PAGES.  A page
  83  *      is some number of hardware pages, depending on the target machine.
  84  */
  85
  86 #ifndef ASSEMBLER
  87
  88 #define PAGE_SIZE_64 (unsigned long long)PAGE_SIZE              /* pagesize in addr units */
  89 #define PAGE_MASK_64 (unsigned long long)PAGE_MASK              /* mask for off in page */
  90
  91 /*
  92  *      Convert addresses to pages and vice versa.  No rounding is used.
  93  *      The atop_32 and ptoa_32 macros should not be use on 64 bit types.
  94  *      The round_page_64 and trunc_page_64 macros should be used instead.
  95  */
  96
  97 #define atop_32(x) ((uint32_t)(x) >> PAGE_SHIFT)
  98 #define ptoa_32(x) ((uint32_t)(x) << PAGE_SHIFT)
  99 #define atop_64(x) ((uint64_t)(x) >> PAGE_SHIFT)
 100 #define ptoa_64(x) ((uint64_t)(x) << PAGE_SHIFT)
 101
 102 #define atop_kernel(x) ((vm_address_t)(x) >> PAGE_SHIFT)
 103 #define ptoa_kernel(x) ((vm_address_t)(x) << PAGE_SHIFT)
 104
 105 /*
 106  *      While the following block is enabled, the legacy atop and ptoa
 107  *      macros will behave correctly.  If not, they will generate
 108  *      invalid lvalue errors.
 109  */
 110
 111 #if 1
 112 #define atop(x) ((vm_address_t)(x) >> PAGE_SHIFT)
 113 #define ptoa(x) ((vm_address_t)(x) << PAGE_SHIFT)
 114 #else
 115 #define atop(x) (0UL = 0)
 116 #define ptoa(x) (0UL = 0)
 117 #endif
 118
 119 /*
 120  *      Page-size rounding macros for the Public fixed-width VM types.
 121  */
 122 #define mach_vm_round_page(x) (((mach_vm_offset_t)(x) + PAGE_MASK) & ~((signed)PAGE_MASK))
 123 #define mach_vm_trunc_page(x) ((mach_vm_offset_t)(x) & ~((signed)PAGE_MASK))
 124
 125 #define round_page_overflow(in, out) __os_warn_unused(({ \
 126                 bool __ovr = os_add_overflow(in, (__typeof__(*out))PAGE_MASK, out); \
 127                 *out &= ~((__typeof__(*out))PAGE_MASK); \
 128                 __ovr; \
 129         }))
 130
 131 static inline int OS_WARN_RESULT
 132 mach_vm_round_page_overflow(mach_vm_offset_t in, mach_vm_offset_t *out)
 133 {
 134         return round_page_overflow(in, out);
 135 }
 136
 137 #define memory_object_round_page(x) (((memory_object_offset_t)(x) + PAGE_MASK) & ~((signed)PAGE_MASK))
 138 #define memory_object_trunc_page(x) ((memory_object_offset_t)(x) & ~((signed)PAGE_MASK))
 139
 140 /*
 141  *      Rounding macros for the legacy (scalable with the current task's
 142  *      address space size) VM types.
 143  */
 144
 145 #define round_page(x) (((vm_offset_t)(x) + PAGE_MASK) & ~((vm_offset_t)PAGE_MASK))
 146 #define trunc_page(x) ((vm_offset_t)(x) & ~((vm_offset_t)PAGE_MASK))
 147
 148 /*
 149  *      Round off or truncate to the nearest page.  These will work
 150  *      for either addresses or counts.  (i.e. 1 byte rounds to 1 page
 151  *      bytes.  The round_page_32 and trunc_page_32 macros should not be
 152  *      use on 64 bit types.  The round_page_64 and trunc_page_64 macros
 153  *      should be used instead.
 154  *
 155  *      These should only be used in the rare case the size of the address
 156  *      or length is hard-coded as 32 or 64 bit.  Otherwise, the macros
 157  *      associated with the specific VM type should be used.
 158  */
 159
 160 #define round_page_32(x) (((uint32_t)(x) + PAGE_MASK) & ~((uint32_t)PAGE_MASK))
 161 #define trunc_page_32(x) ((uint32_t)(x) & ~((uint32_t)PAGE_MASK))
 162 #define round_page_64(x) (((uint64_t)(x) + PAGE_MASK_64) & ~((uint64_t)PAGE_MASK_64))
 163 #define trunc_page_64(x) ((uint64_t)(x) & ~((uint64_t)PAGE_MASK_64))
 164
 165 /*
 166  *      Enable the following block to find uses of xxx_32 macros that should
 167  *      be xxx_64.  These macros only work in C code, not C++.  The resulting
 168  *      binaries are not functional.  Look for invalid lvalue errors in
 169  *      the compiler output.
 170  *
 171  *      Enabling the following block will also find use of the xxx_64 macros
 172  *      that have been passed pointers.  The parameters should be case to an
 173  *      unsigned long type first.  Look for invalid operands to binary + error
 174  *      in the compiler output.
 175  */
 176
 177 #if 0
 178 #undef atop_32
 179 #undef ptoa_32
 180 #undef round_page_32
 181 #undef trunc_page_32
 182 #undef atop_64
 183 #undef ptoa_64
 184 #undef round_page_64
 185 #undef trunc_page_64
 186
 187 #ifndef __cplusplus
 188
 189 #define atop_32(x) \
 190     (__builtin_choose_expr (sizeof(x) != sizeof(uint64_t), \
 191         (*(long *)0), \
 192         (0UL)) = 0)
 193
 194 #define ptoa_32(x) \
 195     (__builtin_choose_expr (sizeof(x) != sizeof(uint64_t), \
 196         (*(long *)0), \
 197         (0UL)) = 0)
 198
 199 #define round_page_32(x) \
 200     (__builtin_choose_expr (sizeof(x) != sizeof(uint64_t), \
 201         (*(long *)0), \
 202         (0UL)) = 0)
 203
 204 #define trunc_page_32(x) \
 205     (__builtin_choose_expr (sizeof(x) != sizeof(uint64_t), \
 206         (*(long *)0), \
 207         (0UL)) = 0)
 208 #else
 209
 210 #define atop_32(x) (0)
 211 #define ptoa_32(x) (0)
 212 #define round_page_32(x) (0)
 213 #define trunc_page_32(x) (0)
 214
 215 #endif /* ! __cplusplus */
 216
 217 #define atop_64(x) ((uint64_t)((x) + (uint8_t *)0))
 218 #define ptoa_64(x) ((uint64_t)((x) + (uint8_t *)0))
 219 #define round_page_64(x) ((uint64_t)((x) + (uint8_t *)0))
 220 #define trunc_page_64(x) ((uint64_t)((x) + (uint8_t *)0))
 221
 222 #endif
 223
 224 /*
 225  *      Determine whether an address is page-aligned, or a count is
 226  *      an exact page multiple.
 227  */
 228
 229 #define page_aligned(x) (((x) & PAGE_MASK) == 0)
 230
 231 extern vm_size_t        mem_size;               /* 32-bit size of memory - limited by maxmem - deprecated */
 232 extern uint64_t         max_mem;                /* 64-bit size of memory - limited by maxmem */
 233
 234 /*
 235  * The default pager does not handle 64-bit offsets inside its objects,
 236  * so this limits the size of anonymous memory objects to 4GB minus 1 page.
 237  * When we need to allocate a chunk of anonymous memory over that size,
 238  * we have to allocate more than one chunk.
 239  */
 240 #define ANON_MAX_SIZE   0xFFFFF000ULL
 241 /*
 242  * Work-around for <rdar://problem/6626493>
 243  * Break large anonymous memory areas into 128MB chunks to alleviate
 244  * the cost of copying when copy-on-write is not possible because a small
 245  * portion of it being wired.
 246  */
 247 #define ANON_CHUNK_SIZE (128ULL * 1024 * 1024) /* 128MB */
 248
 249 #ifdef  XNU_KERNEL_PRIVATE
 250
 251 extern uint64_t         mem_actual;             /* 64-bit size of memory - not limited by maxmem */
 252 extern uint64_t         sane_size;              /* Memory size to use for defaults calculations */
 253 extern addr64_t         vm_last_addr;   /* Highest kernel virtual address known to the VM system */
 254
 255 extern const vm_offset_t        vm_min_kernel_address;
 256 extern const vm_offset_t        vm_max_kernel_address;
 257
 258 extern vm_offset_t              vm_kernel_stext;
 259 extern vm_offset_t              vm_kernel_etext;
 260 extern vm_offset_t              vm_kernel_slid_base;
 261 extern vm_offset_t              vm_kernel_slid_top;
 262 extern vm_offset_t              vm_kernel_slide;
 263 extern vm_offset_t              vm_kernel_addrperm;
 264 extern vm_offset_t              vm_kext_base;
 265 extern vm_offset_t              vm_kext_top;
 266 extern vm_offset_t              vm_kernel_base;
 267 extern vm_offset_t              vm_kernel_top;
 268 extern vm_offset_t              vm_hib_base;
 269
 270 #define VM_KERNEL_IS_SLID(_o)                                                  \
 271                 (((vm_offset_t)(_o) >= vm_kernel_slid_base) &&                 \
 272                  ((vm_offset_t)(_o) <  vm_kernel_slid_top))
 273
 274 #define VM_KERNEL_SLIDE(_u)                                                    \
 275                 ((vm_offset_t)(_u) + vm_kernel_slide)
 276
 277 /*
 278  * The following macros are to be used when exposing kernel addresses to
 279  * userspace via any of the various debug or info facilities that might exist
 280  * (e.g. stackshot, proc_info syscall, etc.). It is important to understand
 281  * the goal of each macro and choose the right one depending on what you are
 282  * trying to do. Misuse of these macros can result in critical data leaks
 283  * which in turn lead to all sorts of system vulnerabilities.
 284  *
 285  * Note that in general the ideal goal is to protect addresses from userspace
 286  * in a way that is reversible assuming you know the permutation and/or slide.
 287  *
 288  * The macros are as follows:
 289  *
 290  * VM_KERNEL_UNSLIDE:
 291  *     Use this macro when you are exposing an address to userspace which is
 292  *     a "static" kernel or kext address (i.e. coming from text or data
 293  *     sections). These are the addresses which get "slid" via ASLR on kernel
 294  *     or kext load, and it's precisely the slide value we are trying to
 295  *     protect from userspace.
 296  *
 297  * VM_KERNEL_ADDRPERM:
 298  *     Use this macro when you are exposing an address to userspace which is
 299  *     coming from the kernel's "heap". Since these adresses are not "loaded"
 300  *     from anywhere, there is no slide applied and we instead apply the
 301  *     permutation value to obscure the address.
 302  *
 303  * VM_KERNEL_UNSLIDE_OR_ADDRPERM:
 304  *     Use this macro when you are exposing an address to userspace that could
 305  *     come from either kernel text/data *or* the heap. This is a rare case,
 306  *     but one that does come up and must be handled correctly. If the argument
 307  *     is known to be lower than any potential heap address, no transformation
 308  *     is applied, to avoid revealing the operation on a constant.
 309  *
 310  * Nesting of these macros should be considered invalid.
 311  */
 312 #define VM_KERNEL_UNSLIDE(_v)                                                  \
 313                 ((VM_KERNEL_IS_SLID(_v)) ?                                     \
 314                         (vm_offset_t)(_v) - vm_kernel_slide :                   \
 315                         (vm_offset_t)(_v))
 316
 317 #define VM_KERNEL_ADDRPERM(_v)                                                 \
 318                 (((vm_offset_t)(_v) == 0) ?                                    \
 319                         (vm_offset_t)(0) :                                     \
 320                         (vm_offset_t)(_v) + vm_kernel_addrperm)
 321
 322 #define VM_KERNEL_UNSLIDE_OR_PERM(_v)                                          \
 323                 ((VM_KERNEL_IS_SLID(_v)) ?                                     \
 324                         (vm_offset_t)(_v) - vm_kernel_slide :    \
 325                  ((vm_offset_t)(_v) >= VM_MIN_KERNEL_AND_KEXT_ADDRESS ? VM_KERNEL_ADDRPERM(_v) : (vm_offset_t)(_v)))
 326
 327
 328 #endif  /* XNU_KERNEL_PRIVATE */
 329
 330 extern vm_size_t        page_size;
 331 extern vm_size_t        page_mask;
 332 extern int              page_shift;
 333
 334 /* We need a way to get rid of compiler warnings when we cast from   */
 335 /* a 64 bit value to an address (which may be 32 bits or 64-bits).   */
 336 /* An intptr_t is used convert the value to the right precision, and */
 337 /* then to an address. This macro is also used to convert addresses  */
 338 /* to 32-bit integers, which is a hard failure for a 64-bit kernel   */
 339 #include <stdint.h>
 340 #ifndef __CAST_DOWN_CHECK
 341 #define __CAST_DOWN_CHECK
 342
 343 #define CAST_DOWN( type, addr ) \
 344     ( ((type)((uintptr_t) (addr)/(sizeof(type) < sizeof(uintptr_t) ? 0 : 1))) )
 345
 346 #define CAST_DOWN_EXPLICIT( type, addr )  ( ((type)((uintptr_t) (addr))) )
 347
 348 #endif /* __CAST_DOWN_CHECK */
 349
 350 #endif  /* ASSEMBLER */
 351
 352 #endif  /* KERNEL */
 353
 354 #endif  /* _MACH_VM_PARAM_H_ */