sys/external/bsd/compiler_rt/dist/test/Unit/clear_cache_test.c

   1 //===-- clear_cache_test.c - Test clear_cache -----------------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is dual licensed under the MIT and the University of Illinois Open
   6 // Source Licenses. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10
  11 #include <stdio.h>
  12 #include <string.h>
  13 #include <stdint.h>
  14 #if defined(_WIN32)
  15 #include <windows.h>
  16 void __clear_cache(void* start, void* end)
  17 {
  18     if (!FlushInstructionCache(GetCurrentProcess(), start, end-start))
  19         exit(1);
  20 }
  21 #else
  22 #include <sys/mman.h>
  23 extern void __clear_cache(void* start, void* end);
  24 #endif
  25
  26
  27
  28
  29 typedef int (*pfunc)(void);
  30
  31 int func1()
  32 {
  33     return 1;
  34 }
  35
  36 int func2()
  37 {
  38     return 2;
  39 }
  40
  41
  42
  43 unsigned char execution_buffer[128];
  44
  45 int main()
  46 {
  47     // make executable the page containing execution_buffer
  48     char* start = (char*)((uintptr_t)execution_buffer & (-4095));
  49     char* end = (char*)((uintptr_t)(&execution_buffer[128+4096]) & (-4095));
  50 #if defined(_WIN32)
  51     DWORD dummy_oldProt;
  52     MEMORY_BASIC_INFORMATION b;
  53     if (!VirtualQuery(start, &b, sizeof(b)))
  54         return 1;
  55     if (!VirtualProtect(b.BaseAddress, b.RegionSize, PAGE_EXECUTE_READWRITE, &b.Protect))
  56 #else
  57     if (mprotect(start, end-start, PROT_READ|PROT_WRITE|PROT_EXEC) != 0)
  58 #endif
  59         return 1;
  60
  61     // verify you can copy and execute a function
  62     memcpy(execution_buffer, (void *)(uintptr_t)&func1, 128);
  63     __clear_cache(execution_buffer, &execution_buffer[128]);
  64     pfunc f1 = (pfunc)(uintptr_t)execution_buffer;
  65     if ((*f1)() != 1)
  66         return 1;
  67
  68     // verify you can overwrite a function with another
  69     memcpy(execution_buffer, (void *)(uintptr_t)&func2, 128);
  70     __clear_cache(execution_buffer, &execution_buffer[128]);
  71     pfunc f2 = (pfunc)(uintptr_t)execution_buffer;
  72     if ((*f2)() != 2)
  73         return 1;
  74
  75     return 0;
  76 }