/* * Userspace test harness for load_unaligned_zeropad. Creates two * pages and uses mprotect to prevent access to the second page and * a SEGV handler that walks the exception tables and runs the fixup * routine. * * The results are compared against a normal load that is that is * performed while access to the second page is enabled via mprotect. * * Copyright (C) 2014 Anton Blanchard <anton@au.ibm.com>, IBM * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #include <stdlib.h> #include <string.h> #include <stdio.h> #include <stdbool.h> #include <signal.h> #include <unistd.h> #include <sys/mman.h> #define FIXUP_SECTION ".ex_fixup" #include "word-at-a-time.h" #include "utils.h" static int page_size; static char *mem_region; static int protect_region(void) { if (mprotect(mem_region + page_size, page_size, PROT_NONE)) { perror("mprotect"); return 1; } return 0; } static int unprotect_region(void) { if (mprotect(mem_region + page_size, page_size, PROT_READ|PROT_WRITE)) { perror("mprotect"); return 1; } return 0; } extern char __start___ex_table[]; extern char __stop___ex_table[]; #if defined(__powerpc64__) #define UCONTEXT_NIA(UC) (UC)->uc_mcontext.gp_regs[PT_NIP] #elif defined(__powerpc__) #define UCONTEXT_NIA(UC) (UC)->uc_mcontext.uc_regs->gregs[PT_NIP] #else #error implement UCONTEXT_NIA #endif static int segv_error; static void segv_handler(int signr, siginfo_t *info, void *ptr) { ucontext_t *uc = (ucontext_t *)ptr; unsigned long addr = (unsigned long)info->si_addr; unsigned long *ip = &UCONTEXT_NIA(uc); unsigned long *ex_p = (unsigned long *)__start___ex_table; while (ex_p < (unsigned long *)__stop___ex_table) { unsigned long insn, fixup; insn = *ex_p++; fixup = *ex_p++; if (insn == *ip) { *ip = fixup; return; } } printf("No exception table match for NIA %lx ADDR %lx\n", *ip, addr); segv_error++; } static void setup_segv_handler(void) { struct sigaction action; memset(&action, 0, sizeof(action)); action.sa_sigaction = segv_handler; action.sa_flags = SA_SIGINFO; sigaction(SIGSEGV, &action, NULL); } static int do_one_test(char *p, int page_offset) { unsigned long should; unsigned long got; FAIL_IF(unprotect_region()); should = *(unsigned long *)p; FAIL_IF(protect_region()); got = load_unaligned_zeropad(p); if (should != got) printf("offset %u load_unaligned_zeropad returned 0x%lx, should be 0x%lx\n", page_offset, got, should); return 0; } static int test_body(void) { unsigned long i; page_size = getpagesize(); mem_region = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); FAIL_IF(mem_region == MAP_FAILED); for (i = 0; i < page_size; i++) mem_region[i] = i; memset(mem_region+page_size, 0, page_size); setup_segv_handler(); for (i = 0; i < page_size; i++) FAIL_IF(do_one_test(mem_region+i, i)); FAIL_IF(segv_error); return 0; } int main(void) { return test_harness(test_body, "load_unaligned_zeropad"); }