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>
__clear_cache(void * start,void * end)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
func1()31 int func1()
32 {
33 return 1;
34 }
35
func2()36 int func2()
37 {
38 return 2;
39 }
40
41
42
43 unsigned char execution_buffer[128];
44
main()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 }
77