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.
func1()22 static int func1() { return 1; }
func2()23 static int func2() { return 2; }
24
25 void __attribute__((noinline))
memcpy_f(void * dst,const void * src,size_t n)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))
realign_f(void * dst,const void * src,size_t n)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
main()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 }
104