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