compiler-rt/test/builtins/Unit/clear_cache_test.c

   1 // REQUIRES: native-run
   2 // UNSUPPORTED: target={{(arm|aarch64).*}}
   3 // RUN: %clang_builtins %s %librt -o %t && %run %t
   4 // REQUIRES: librt_has_clear_cache
   5
   6 #include <stdio.h>
   7 #include <string.h>
   8 #include <stdint.h>
   9
  10 #if defined(_WIN32)
  11 #include <windows.h>
  12 #else
  13 #include <unistd.h>
  14 #include <sys/mman.h>
  15 #endif
  16
  17 extern void __clear_cache(void* start, void* end);
  18
  19 typedef int (*pfunc)(void);
  20
  21 // Make these static to avoid ILT jumps for incremental linking on Windows.
  22 static int func1() { return 1; }
  23 static int func2() { return 2; }
  24
  25 void __attribute__((noinline))
  26 memcpy_f(void *dst, const void *src, size_t n) {
  27 // ARM and MIPS naturally align functions, but use the LSB for ISA selection
  28 // (THUMB, MIPS16/uMIPS respectively).  Ensure that the ISA bit is ignored in
  29 // the memcpy
  30 #if defined(__arm__) || defined(__mips__)
  31   memcpy(dst, (void *)((uintptr_t)src & ~1), n);
  32 #else
  33   memcpy(dst, (void *)((uintptr_t)src), n);
  34 #endif
  35 }
  36
  37 // Realign the 'dst' pointer as if it has been returned by memcpy() above.
  38 // We need to split it because we're using two mappings for the same area.
  39 void *__attribute__((noinline))
  40 realign_f(void *dst, const void *src, size_t n) {
  41 #if defined(__arm__) || defined(__mips__)
  42   return (void *)((uintptr_t)dst | ((uintptr_t)src & 1));
  43 #else
  44   return dst;
  45 #endif
  46 }
  47
  48 int main()
  49 {
  50     const int kSize = 128;
  51 #if defined(__NetBSD__)
  52     // we need to create separate RW and RX mappings to satisfy MPROTECT
  53     uint8_t *write_buffer = mmap(0, kSize,
  54                                  PROT_MPROTECT(PROT_READ | PROT_WRITE |
  55                                                PROT_EXEC),
  56                                  MAP_ANON | MAP_PRIVATE, -1, 0);
  57     if (write_buffer == MAP_FAILED)
  58       return 1;
  59     uint8_t *execution_buffer = mremap(write_buffer, kSize, NULL, kSize,
  60                                        MAP_REMAPDUP);
  61     if (execution_buffer == MAP_FAILED)
  62       return 1;
  63
  64     if (mprotect(write_buffer, kSize, PROT_READ | PROT_WRITE) == -1)
  65       return 1;
  66     if (mprotect(execution_buffer, kSize, PROT_READ | PROT_EXEC) == -1)
  67       return 1;
  68 #elif !defined(_WIN32)
  69     uint8_t *execution_buffer = mmap(0, kSize,
  70                                      PROT_READ | PROT_WRITE | PROT_EXEC,
  71                                      MAP_ANON | MAP_PRIVATE, -1, 0);
  72     if (execution_buffer == MAP_FAILED)
  73       return 1;
  74     uint8_t *write_buffer = execution_buffer;
  75 #else
  76     HANDLE mapping = CreateFileMapping(INVALID_HANDLE_VALUE, NULL,
  77                                        PAGE_EXECUTE_READWRITE, 0, kSize, NULL);
  78     if (mapping == NULL)
  79         return 1;
  80
  81     uint8_t* execution_buffer = MapViewOfFile(
  82         mapping, FILE_MAP_ALL_ACCESS | FILE_MAP_EXECUTE, 0, 0, 0);
  83     if (execution_buffer == NULL)
  84         return 1;
  85     uint8_t *write_buffer = execution_buffer;
  86 #endif
  87
  88     // verify you can copy and execute a function
  89     memcpy_f(write_buffer, func1, kSize);
  90     pfunc f1 = (pfunc)realign_f(execution_buffer, func1, kSize);
  91     __clear_cache(execution_buffer, execution_buffer + kSize);
  92     if ((*f1)() != 1)
  93         return 1;
  94
  95     // verify you can overwrite a function with another
  96     memcpy_f(write_buffer, func2, kSize);
  97     pfunc f2 = (pfunc)realign_f(execution_buffer, func2, kSize);
  98     __clear_cache(execution_buffer, execution_buffer + kSize);
  99     if ((*f2)() != 2)
 100         return 1;
 101
 102     return 0;
 103 }