tools/testing/selftests/powerpc/primitives/load_unaligned_zeropad.c

   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 }