| //===-- clear_cache_test.c - Test clear_cache -----------------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is dual licensed under the MIT and the University of Illinois Open |
| // Source Licenses. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| |
| #include <stdio.h> |
| #include <string.h> |
| #include <stdint.h> |
| #include <sys/mman.h> |
| |
| |
| |
| extern void __clear_cache(void* start, void* end); |
| |
| typedef int (*pfunc)(void); |
| |
| int func1() |
| { |
| return 1; |
| } |
| |
| int func2() |
| { |
| return 2; |
| } |
| |
| |
| |
| unsigned char execution_buffer[128]; |
| |
| int main() |
| { |
| // make executable the page containing execution_buffer |
| char* start = (char*)((uintptr_t)execution_buffer & (-4095)); |
| char* end = (char*)((uintptr_t)(&execution_buffer[128+4096]) & (-4095)); |
| if ( mprotect(start, end-start, PROT_READ|PROT_WRITE|PROT_EXEC) != 0 ) |
| return 1; |
| |
| // verify you can copy and execute a function |
| memcpy(execution_buffer, (void *)(uintptr_t)&func1, 128); |
| __clear_cache(execution_buffer, &execution_buffer[128]); |
| pfunc f1 = (pfunc)(uintptr_t)execution_buffer; |
| if ( (*f1)() != 1 ) |
| return 1; |
| |
| // verify you can overwrite a function with another |
| memcpy(execution_buffer, (void *)(uintptr_t)&func2, 128); |
| __clear_cache(execution_buffer, &execution_buffer[128]); |
| pfunc f2 = (pfunc)(uintptr_t)execution_buffer; |
| if ( (*f2)() != 2 ) |
| return 1; |
| |
| return 0; |
| } |