libvtv/vtv_malloc.h

   1 // Copyright (C) 2012-2018 Free Software Foundation, Inc.
   2 //
   3 // This file is part of GCC.
   4 //
   5 // GCC is free software; you can redistribute it and/or modify
   6 // it under the terms of the GNU General Public License as published by
   7 // the Free Software Foundation; either version 3, or (at your option)
   8 // any later version.
   9
  10 // GCC is distributed in the hope that it will be useful,
  11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 // GNU General Public License for more details.
  14
  15 // Under Section 7 of GPL version 3, you are granted additional
  16 // permissions described in the GCC Runtime Library Exception, version
  17 // 3.1, as published by the Free Software Foundation.
  18
  19 // You should have received a copy of the GNU General Public License and
  20 // a copy of the GCC Runtime Library Exception along with this program;
  21 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  22 // <http://www.gnu.org/licenses/>.
  23
  24 #ifndef _VTV_MALLOC_H
  25 #define _VTV_MALLOC_H 1
  26
  27 #include <stdlib.h>
  28
  29 /* Alignment mask for any object returned by the VTV memory pool */
  30 #ifdef __LP64__
  31 #define VTV_ALIGNMENT_MASK (0x7)
  32 #else
  33 #define VTV_ALIGNMENT_MASK (0x3)
  34 #endif
  35
  36 /* The following function is used to instrument the compiler and find
  37    out how many cycles are being spent in various vtable verification
  38    runtime library functions.  */
  39
  40 #ifdef __x86_64__
  41 static inline unsigned long
  42 rdtsc ()
  43 {
  44   unsigned long long hi, lo;
  45
  46   asm volatile ("rdtsc" : "=a" (lo), "=d" (hi));
  47   return hi << 32 | lo;
  48 }
  49 #elif defined (__i386__)
  50 static inline unsigned long long
  51 rdtsc ()
  52 {
  53   unsigned long long var;
  54
  55   asm volatile ("rdtsc" : "=A" (var));
  56
  57   return var;
  58 }
  59 #else
  60 static inline unsigned long long
  61 rdtsc ()
  62 {
  63   /* Create an empty function for unknown architectures, so that the
  64      calls to this function in vtv_malloc.cc and vtv_rts.cc do not cause
  65      compilation errors.  */
  66   return ((unsigned long long) 0);
  67 }
  68 #endif
  69
  70
  71 /* The following variables are used only for debugging and performance tuning
  72    purposes. Therefore they do not need to be "protected".  They cannot be used
  73    to attack the vtable verification system and if they become corrupted it will
  74    not affect the correctness or security of any of the rest of the vtable
  75    verification feature.  */
  76
  77 extern unsigned int num_calls_to_mprotect;
  78 extern unsigned int num_pages_protected;
  79 extern unsigned int num_calls_to_regset;
  80 extern unsigned int num_calls_to_regpair;
  81 extern unsigned long long mprotect_cycles;
  82 extern unsigned long long regset_cycles;
  83 extern unsigned long long regpair_cycles;
  84
  85
  86 /* Function declarations.  */
  87
  88 extern void __vtv_malloc_init (void);
  89 extern void *__vtv_malloc (size_t size) __attribute__ ((malloc));
  90 extern void __vtv_free (void * ptr);
  91 extern void __vtv_malloc_protect (void);
  92 extern void __vtv_malloc_unprotect (void);
  93 extern void __vtv_malloc_stats (void);
  94 extern void __vtv_malloc_dump_stats (void);
  95 extern int __vtv_count_mmapped_pages (void);
  96
  97 #if defined (__CYGWIN__) || defined (__MINGW32__)
  98 extern "C" int mprotect (void *addr, int len, int prot);
  99
 100   #define PROT_READ 0x1
 101   #define PROT_WRITE 0x2
 102 #endif
 103
 104 #endif /* vtv_malloc.h */