1 // REQUIRES: native-run
2 // UNSUPPORTED: arm, aarch64
3 // RUN: %clang_builtins %s %librt -o %t && %run %t
4 // REQUIRES: librt_has_clear_cache
5 //===-- clear_cache_test.c - Test clear_cache -----------------------------===//
6 //
7 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
8 // See https://llvm.org/LICENSE.txt for license information.
9 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
10 //
11 //===----------------------------------------------------------------------===//
12 
13 
14 #include <stdio.h>
15 #include <string.h>
16 #include <stdint.h>
17 
18 #if defined(_WIN32)
19 #include <windows.h>
20 #else
21 #include <unistd.h>
22 #include <sys/mman.h>
23 #endif
24 
25 extern void __clear_cache(void* start, void* end);
26 
27 typedef int (*pfunc)(void);
28 
29 // Make these static to avoid ILT jumps for incremental linking on Windows.
30 static int func1() { return 1; }
31 static int func2() { return 2; }
32 
33 void *__attribute__((noinline))
34 memcpy_f(void *dst, const void *src, size_t n) {
35 // ARM and MIPS nartually align functions, but use the LSB for ISA selection
36 // (THUMB, MIPS16/uMIPS respectively).  Ensure that the ISA bit is ignored in
37 // the memcpy
38 #if defined(__arm__) || defined(__mips__)
39   return (void *)((uintptr_t)memcpy(dst, (void *)((uintptr_t)src & ~1), n) |
40                   ((uintptr_t)src & 1));
41 #else
42   return memcpy(dst, (void *)((uintptr_t)src), n);
43 #endif
44 }
45 
46 int main()
47 {
48     const int kSize = 128;
49 #if !defined(_WIN32)
50     uint8_t *execution_buffer = mmap(0, kSize,
51                                      PROT_READ | PROT_WRITE | PROT_EXEC,
52                                      MAP_ANON | MAP_PRIVATE, -1, 0);
53     if (execution_buffer == MAP_FAILED)
54       return 1;
55 #else
56     HANDLE mapping = CreateFileMapping(INVALID_HANDLE_VALUE, NULL,
57                                        PAGE_EXECUTE_READWRITE, 0, kSize, NULL);
58     if (mapping == NULL)
59         return 1;
60 
61     uint8_t* execution_buffer = MapViewOfFile(
62         mapping, FILE_MAP_ALL_ACCESS | FILE_MAP_EXECUTE, 0, 0, 0);
63     if (execution_buffer == NULL)
64         return 1;
65 #endif
66 
67     // verify you can copy and execute a function
68     pfunc f1 = (pfunc)memcpy_f(execution_buffer, func1, kSize);
69     __clear_cache(execution_buffer, execution_buffer + kSize);
70     if ((*f1)() != 1)
71         return 1;
72 
73     // verify you can overwrite a function with another
74     pfunc f2 = (pfunc)memcpy_f(execution_buffer, func2, kSize);
75     __clear_cache(execution_buffer, execution_buffer + kSize);
76     if ((*f2)() != 2)
77         return 1;
78 
79     return 0;
80 }
81