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 static inline unsigned long __fls(unsigned long x); 29 30 #include "word-at-a-time.h" 31 32 #include "utils.h" 33 34 static inline unsigned long __fls(unsigned long x) 35 { 36 int lz; 37 38 asm (PPC_CNTLZL "%0,%1" : "=r" (lz) : "r" (x)); 39 return sizeof(unsigned long) - 1 - lz; 40 } 41 42 static int page_size; 43 static char *mem_region; 44 45 static int protect_region(void) 46 { 47 if (mprotect(mem_region + page_size, page_size, PROT_NONE)) { 48 perror("mprotect"); 49 return 1; 50 } 51 52 return 0; 53 } 54 55 static int unprotect_region(void) 56 { 57 if (mprotect(mem_region + page_size, page_size, PROT_READ|PROT_WRITE)) { 58 perror("mprotect"); 59 return 1; 60 } 61 62 return 0; 63 } 64 65 extern char __start___ex_table[]; 66 extern char __stop___ex_table[]; 67 68 #if defined(__powerpc64__) 69 #define UCONTEXT_NIA(UC) (UC)->uc_mcontext.gp_regs[PT_NIP] 70 #elif defined(__powerpc__) 71 #define UCONTEXT_NIA(UC) (UC)->uc_mcontext.uc_regs->gregs[PT_NIP] 72 #else 73 #error implement UCONTEXT_NIA 74 #endif 75 76 static int segv_error; 77 78 static void segv_handler(int signr, siginfo_t *info, void *ptr) 79 { 80 ucontext_t *uc = (ucontext_t *)ptr; 81 unsigned long addr = (unsigned long)info->si_addr; 82 unsigned long *ip = &UCONTEXT_NIA(uc); 83 unsigned long *ex_p = (unsigned long *)__start___ex_table; 84 85 while (ex_p < (unsigned long *)__stop___ex_table) { 86 unsigned long insn, fixup; 87 88 insn = *ex_p++; 89 fixup = *ex_p++; 90 91 if (insn == *ip) { 92 *ip = fixup; 93 return; 94 } 95 } 96 97 printf("No exception table match for NIA %lx ADDR %lx\n", *ip, addr); 98 segv_error++; 99 } 100 101 static void setup_segv_handler(void) 102 { 103 struct sigaction action; 104 105 memset(&action, 0, sizeof(action)); 106 action.sa_sigaction = segv_handler; 107 action.sa_flags = SA_SIGINFO; 108 sigaction(SIGSEGV, &action, NULL); 109 } 110 111 static int do_one_test(char *p, int page_offset) 112 { 113 unsigned long should; 114 unsigned long got; 115 116 FAIL_IF(unprotect_region()); 117 should = *(unsigned long *)p; 118 FAIL_IF(protect_region()); 119 120 got = load_unaligned_zeropad(p); 121 122 if (should != got) 123 printf("offset %u load_unaligned_zeropad returned 0x%lx, should be 0x%lx\n", page_offset, got, should); 124 125 return 0; 126 } 127 128 static int test_body(void) 129 { 130 unsigned long i; 131 132 page_size = getpagesize(); 133 mem_region = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE, 134 MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 135 136 FAIL_IF(mem_region == MAP_FAILED); 137 138 for (i = 0; i < page_size; i++) 139 mem_region[i] = i; 140 141 memset(mem_region+page_size, 0, page_size); 142 143 setup_segv_handler(); 144 145 for (i = 0; i < page_size; i++) 146 FAIL_IF(do_one_test(mem_region+i, i)); 147 148 FAIL_IF(segv_error); 149 150 return 0; 151 } 152 153 int main(void) 154 { 155 return test_harness(test_body, "load_unaligned_zeropad"); 156 } 157