LXR linux/tools/testing/selftests/powerpc/primitives/load_unaligned

   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
  33static int page_size;
  34static char *mem_region;
  35
  36static 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
  46static 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
  56extern char __start___ex_table[];
  57extern 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
  67static int segv_error;
  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        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
  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
 116        return 0;
 117}
 118
 119static 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
 144int main(void)
 145{
 146        return test_harness(test_body, "load_unaligned_zeropad");
 147}
 148