clear_cache_test.c revision 77ed6142daed1e068fbda64405d0de9845e40e1a
1//===-- clear_cache_test.c - Test clear_cache -----------------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9 10 11#include <stdio.h> 12#include <string.h> 13#include <stdint.h> 14#include <sys/mman.h> 15 16 17 18extern void __clear_cache(void* start, void* end); 19 20typedef int (*pfunc)(void); 21 22int func1() 23{ 24 return 1; 25} 26 27int func2() 28{ 29 return 2; 30} 31 32 33 34unsigned char execution_buffer[128]; 35 36int main() 37{ 38 // make executable the page containing execution_buffer 39 char* start = (char*)((uintptr_t)execution_buffer & (-4095)); 40 char* end = (char*)((uintptr_t)(&execution_buffer[128+4096]) & (-4095)); 41 if ( mprotect(start, end-start, PROT_READ|PROT_WRITE|PROT_EXEC) != 0 ) 42 return 1; 43 44 // verify you can copy and execute a function 45 memcpy(execution_buffer, (void *)(uintptr_t)&func1, 128); 46 __clear_cache(execution_buffer, &execution_buffer[128]); 47 pfunc f1 = (pfunc)(uintptr_t)execution_buffer; 48 if ( (*f1)() != 1 ) 49 return 1; 50 51 // verify you can overwrite a function with another 52 memcpy(execution_buffer, (void *)(uintptr_t)&func2, 128); 53 __clear_cache(execution_buffer, &execution_buffer[128]); 54 pfunc f2 = (pfunc)(uintptr_t)execution_buffer; 55 if ( (*f2)() != 2 ) 56 return 1; 57 58 return 0; 59} 60