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 memcpy(dst, (void *)((uintptr_t)src & ~1), n); 40 #else 41 memcpy(dst, (void *)((uintptr_t)src), n); 42 #endif 43 } 44 45 // Realign the 'dst' pointer as if it has been returned by memcpy() above. 46 // We need to split it because we're using two mappings for the same area. 47 void *__attribute__((noinline)) 48 realign_f(void *dst, const void *src, size_t n) { 49 #if defined(__arm__) || defined(__mips__) 50 return (void *)((uintptr_t)dst | ((uintptr_t)src & 1)); 51 #else 52 return dst; 53 #endif 54 } 55 56 int main() 57 { 58 const int kSize = 128; 59 #if defined(__NetBSD__) 60 // we need to create separate RW and RX mappings to satisfy MPROTECT 61 uint8_t *write_buffer = mmap(0, kSize, 62 PROT_MPROTECT(PROT_READ | PROT_WRITE | 63 PROT_EXEC), 64 MAP_ANON | MAP_PRIVATE, -1, 0); 65 if (write_buffer == MAP_FAILED) 66 return 1; 67 uint8_t *execution_buffer = mremap(write_buffer, kSize, NULL, kSize, 68 MAP_REMAPDUP); 69 if (execution_buffer == MAP_FAILED) 70 return 1; 71 72 if (mprotect(write_buffer, kSize, PROT_READ | PROT_WRITE) == -1) 73 return 1; 74 if (mprotect(execution_buffer, kSize, PROT_READ | PROT_EXEC) == -1) 75 return 1; 76 #elif !defined(_WIN32) 77 uint8_t *execution_buffer = mmap(0, kSize, 78 PROT_READ | PROT_WRITE | PROT_EXEC, 79 MAP_ANON | MAP_PRIVATE, -1, 0); 80 if (execution_buffer == MAP_FAILED) 81 return 1; 82 uint8_t *write_buffer = execution_buffer; 83 #else 84 HANDLE mapping = CreateFileMapping(INVALID_HANDLE_VALUE, NULL, 85 PAGE_EXECUTE_READWRITE, 0, kSize, NULL); 86 if (mapping == NULL) 87 return 1; 88 89 uint8_t* execution_buffer = MapViewOfFile( 90 mapping, FILE_MAP_ALL_ACCESS | FILE_MAP_EXECUTE, 0, 0, 0); 91 if (execution_buffer == NULL) 92 return 1; 93 uint8_t *write_buffer = execution_buffer; 94 #endif 95 96 // verify you can copy and execute a function 97 memcpy_f(write_buffer, func1, kSize); 98 pfunc f1 = (pfunc)realign_f(execution_buffer, func1, kSize); 99 __clear_cache(execution_buffer, execution_buffer + kSize); 100 if ((*f1)() != 1) 101 return 1; 102 103 // verify you can overwrite a function with another 104 memcpy_f(write_buffer, func2, kSize); 105 pfunc f2 = (pfunc)realign_f(execution_buffer, func2, kSize); 106 __clear_cache(execution_buffer, execution_buffer + kSize); 107 if ((*f2)() != 2) 108 return 1; 109 110 return 0; 111 } 112