1 /* 2 * Userspace test harness for load_unaligned_zeropad. Creates two 3 * pages and uses mprotect to prevent access to the second page and 4 * a SEGV handler that walks the exception tables and runs the fixup 5 * routine. 6 * 7 * The results are compared against a normal load that is that is 8 * performed while access to the second page is enabled via mprotect. 9 * 10 * Copyright (C) 2014 Anton Blanchard <anton@au.ibm.com>, IBM 11 * 12 * This program is free software; you can redistribute it and/or 13 * modify it under the terms of the GNU General Public License 14 * as published by the Free Software Foundation; either version 15 * 2 of the License, or (at your option) any later version. 16 */ 17 18 #include <stdlib.h> 19 #include <string.h> 20 #include <stdio.h> 21 #include <stdbool.h> 22 #include <signal.h> 23 #include <unistd.h> 24 #include <sys/mman.h> 25 26 #define FIXUP_SECTION ".ex_fixup" 27 28 #include "word-at-a-time.h" 29 30 #include "utils.h" 31 32 33 static int page_size; 34 static char *mem_region; 35 36 static int protect_region(void) 37 { 38 if (mprotect(mem_region + page_size, page_size, PROT_NONE)) { 39 perror("mprotect"); 40 return 1; 41 } 42 43 return 0; 44 } 45 46 static int unprotect_region(void) 47 { 48 if (mprotect(mem_region + page_size, page_size, PROT_READ|PROT_WRITE)) { 49 perror("mprotect"); 50 return 1; 51 } 52 53 return 0; 54 } 55 56 extern char __start___ex_table[]; 57 extern char __stop___ex_table[]; 58 59 #if defined(__powerpc64__) 60 #define UCONTEXT_NIA(UC) (UC)->uc_mcontext.gp_regs[PT_NIP] 61 #elif defined(__powerpc__) 62 #define UCONTEXT_NIA(UC) (UC)->uc_mcontext.uc_regs->gregs[PT_NIP] 63 #else 64 #error implement UCONTEXT_NIA 65 #endif 66 67 static int segv_error; 68 69 static void segv_handler(int signr, siginfo_t *info, void *ptr) 70 { 71 ucontext_t *uc = (ucontext_t *)ptr; 72 unsigned long addr = (unsigned long)info->si_addr; 73 unsigned long *ip = &UCONTEXT_NIA(uc); 74 unsigned long *ex_p = (unsigned long *)__start___ex_table; 75 76 while (ex_p < (unsigned long *)__stop___ex_table) { 77 unsigned long insn, fixup; 78 79 insn = *ex_p++; 80 fixup = *ex_p++; 81 82 if (insn == *ip) { 83 *ip = fixup; 84 return; 85 } 86 } 87 88 printf("No exception table match for NIA %lx ADDR %lx\n", *ip, addr); 89 segv_error++; 90 } 91 92 static void setup_segv_handler(void) 93 { 94 struct sigaction action; 95 96 memset(&action, 0, sizeof(action)); 97 action.sa_sigaction = segv_handler; 98 action.sa_flags = SA_SIGINFO; 99 sigaction(SIGSEGV, &action, NULL); 100 } 101 102 static int do_one_test(char *p, int page_offset) 103 { 104 unsigned long should; 105 unsigned long got; 106 107 FAIL_IF(unprotect_region()); 108 should = *(unsigned long *)p; 109 FAIL_IF(protect_region()); 110 111 got = load_unaligned_zeropad(p); 112 113 if (should != got) 114 printf("offset %u load_unaligned_zeropad returned 0x%lx, should be 0x%lx\n", page_offset, got, should); 115 116 return 0; 117 } 118 119 static int test_body(void) 120 { 121 unsigned long i; 122 123 page_size = getpagesize(); 124 mem_region = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE, 125 MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 126 127 FAIL_IF(mem_region == MAP_FAILED); 128 129 for (i = 0; i < page_size; i++) 130 mem_region[i] = i; 131 132 memset(mem_region+page_size, 0, page_size); 133 134 setup_segv_handler(); 135 136 for (i = 0; i < page_size; i++) 137 FAIL_IF(do_one_test(mem_region+i, i)); 138 139 FAIL_IF(segv_error); 140 141 return 0; 142 } 143 144 int main(void) 145 { 146 return test_harness(test_body, "load_unaligned_zeropad"); 147 } 148