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

   1 // REQUIRES: native-run
   2 // RUN: %clang_builtins %s %librt -o %t && %run_nomprotect %t
   3 // REQUIRES: librt_has_enable_execute_stack
   4
   5 #include <stdio.h>
   6 #include <string.h>
   7 #include <stdint.h>
   8 extern void __clear_cache(void* start, void* end);
   9 extern void __enable_execute_stack(void* addr);
  10
  11 typedef int (*pfunc)(void);
  12
  13 // Make these static to avoid ILT jumps for incremental linking on Windows.
  14 static int func1() { return 1; }
  15 static int func2() { return 2; }
  16
  17 void *__attribute__((noinline))
  18 memcpy_f(void *dst, const void *src, size_t n) {
  19 // ARM and MIPS naturally align functions, but use the LSB for ISA selection
  20 // (THUMB, MIPS16/uMIPS respectively).  Ensure that the ISA bit is ignored in
  21 // the memcpy
  22 #if defined(__arm__) || defined(__mips__)
  23   return (void *)((uintptr_t)memcpy(dst, (void *)((uintptr_t)src & ~1), n) |
  24                   ((uintptr_t)src & 1));
  25 #else
  26   return memcpy(dst, (void *)((uintptr_t)src), n);
  27 #endif
  28 }
  29
  30 int main()
  31 {
  32 #if defined(__ve__)
  33     unsigned char execution_buffer[128] __attribute__((__aligned__(8)));
  34 #else
  35     unsigned char execution_buffer[128];
  36 #endif
  37     // mark stack page containing execution_buffer to be executable
  38     __enable_execute_stack(execution_buffer);
  39
  40     // verify you can copy and execute a function
  41     pfunc f1 = (pfunc)memcpy_f(execution_buffer, func1, 128);
  42     __clear_cache(execution_buffer, &execution_buffer[128]);
  43     printf("f1: %p\n", f1);
  44     if ((*f1)() != 1)
  45         return 1;
  46
  47     // verify you can overwrite a function with another
  48     pfunc f2 = (pfunc)memcpy_f(execution_buffer, func2, 128);
  49     __clear_cache(execution_buffer, &execution_buffer[128]);
  50     if ((*f2)() != 2)
  51         return 1;
  52
  53     return 0;
  54 }