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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Userspace test harness for load_unaligned_zeropad. Creates two4 * pages and uses mprotect to prevent access to the second page and5 * a SEGV handler that walks the exception tables and runs the fixup6 * routine.7 *8 * The results are compared against a normal load that is that is9 * performed while access to the second page is enabled via mprotect.10 *11 * Copyright (C) 2014 Anton Blanchard <anton@au.ibm.com>, IBM12 */13 14#include <stdlib.h>15#include <string.h>16#include <stdio.h>17#include <stdbool.h>18#include <signal.h>19#include <unistd.h>20#include <sys/mman.h>21 22#define FIXUP_SECTION ".ex_fixup"23 24static inline unsigned long __fls(unsigned long x);25 26#include "word-at-a-time.h"27 28#include "utils.h"29 30static inline unsigned long __fls(unsigned long x)31{32 int lz;33 34 asm (PPC_CNTLZL "%0,%1" : "=r" (lz) : "r" (x));35 return sizeof(unsigned long) - 1 - lz;36}37 38static int page_size;39static char *mem_region;40 41static int protect_region(void)42{43 if (mprotect(mem_region + page_size, page_size, PROT_NONE)) {44 perror("mprotect");45 return 1;46 }47 48 return 0;49}50 51static int unprotect_region(void)52{53 if (mprotect(mem_region + page_size, page_size, PROT_READ|PROT_WRITE)) {54 perror("mprotect");55 return 1;56 }57 58 return 0;59}60 61extern char __start___ex_table[];62extern char __stop___ex_table[];63 64struct extbl_entry {65 int insn;66 int fixup;67};68 69static 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 struct extbl_entry *entry = (struct extbl_entry *)__start___ex_table;75 76 while (entry < (struct extbl_entry *)__stop___ex_table) {77 unsigned long insn, fixup;78 79 insn = (unsigned long)&entry->insn + entry->insn;80 fixup = (unsigned long)&entry->fixup + entry->fixup;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 abort();90}91 92static 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 102static 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 return 1;116 }117 118 return 0;119}120 121static int test_body(void)122{123 unsigned long i;124 125 page_size = getpagesize();126 mem_region = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE,127 MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);128 129 FAIL_IF(mem_region == MAP_FAILED);130 131 for (i = 0; i < page_size; i++)132 mem_region[i] = i;133 134 memset(mem_region+page_size, 0, page_size);135 136 setup_segv_handler();137 138 for (i = 0; i < page_size; i++)139 FAIL_IF(do_one_test(mem_region+i, i));140 141 return 0;142}143 144int main(void)145{146 return test_harness(test_body, "load_unaligned_zeropad");147}148