fe2a1bb1db
It is a rarely exercised case, so we want to have a test to ensure it works as required. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
147 lines
3.1 KiB
C
147 lines
3.1 KiB
C
/*
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* Userspace test harness for load_unaligned_zeropad. Creates two
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* pages and uses mprotect to prevent access to the second page and
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* a SEGV handler that walks the exception tables and runs the fixup
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* routine.
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*
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* The results are compared against a normal load that is that is
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* performed while access to the second page is enabled via mprotect.
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*
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* Copyright (C) 2014 Anton Blanchard <anton@au.ibm.com>, IBM
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <stdlib.h>
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#include <string.h>
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#include <stdio.h>
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#include <stdbool.h>
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#include <signal.h>
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#include <unistd.h>
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#include <sys/mman.h>
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#define FIXUP_SECTION ".ex_fixup"
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#include "word-at-a-time.h"
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#include "utils.h"
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static int page_size;
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static char *mem_region;
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static int protect_region(void)
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{
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if (mprotect(mem_region + page_size, page_size, PROT_NONE)) {
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perror("mprotect");
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return 1;
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}
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return 0;
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}
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static int unprotect_region(void)
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{
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if (mprotect(mem_region + page_size, page_size, PROT_READ|PROT_WRITE)) {
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perror("mprotect");
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return 1;
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}
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return 0;
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}
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extern char __start___ex_table[];
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extern char __stop___ex_table[];
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#if defined(__powerpc64__)
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#define UCONTEXT_NIA(UC) (UC)->uc_mcontext.gp_regs[PT_NIP]
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#elif defined(__powerpc__)
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#define UCONTEXT_NIA(UC) (UC)->uc_mcontext.uc_regs->gregs[PT_NIP]
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#else
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#error implement UCONTEXT_NIA
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#endif
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static int segv_error;
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static void segv_handler(int signr, siginfo_t *info, void *ptr)
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{
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ucontext_t *uc = (ucontext_t *)ptr;
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unsigned long addr = (unsigned long)info->si_addr;
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unsigned long *ip = &UCONTEXT_NIA(uc);
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unsigned long *ex_p = (unsigned long *)__start___ex_table;
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while (ex_p < (unsigned long *)__stop___ex_table) {
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unsigned long insn, fixup;
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insn = *ex_p++;
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fixup = *ex_p++;
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if (insn == *ip) {
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*ip = fixup;
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return;
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}
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}
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printf("No exception table match for NIA %lx ADDR %lx\n", *ip, addr);
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segv_error++;
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}
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static void setup_segv_handler(void)
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{
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struct sigaction action;
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memset(&action, 0, sizeof(action));
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action.sa_sigaction = segv_handler;
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action.sa_flags = SA_SIGINFO;
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sigaction(SIGSEGV, &action, NULL);
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}
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static int do_one_test(char *p, int page_offset)
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{
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unsigned long should;
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unsigned long got;
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FAIL_IF(unprotect_region());
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should = *(unsigned long *)p;
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FAIL_IF(protect_region());
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got = load_unaligned_zeropad(p);
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if (should != got)
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printf("offset %u load_unaligned_zeropad returned 0x%lx, should be 0x%lx\n", page_offset, got, should);
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return 0;
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}
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static int test_body(void)
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{
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unsigned long i;
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page_size = getpagesize();
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mem_region = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE,
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MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
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FAIL_IF(mem_region == MAP_FAILED);
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for (i = 0; i < page_size; i++)
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mem_region[i] = i;
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memset(mem_region+page_size, 0, page_size);
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setup_segv_handler();
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for (i = 0; i < page_size; i++)
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FAIL_IF(do_one_test(mem_region+i, i));
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FAIL_IF(segv_error);
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return 0;
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}
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int main(void)
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{
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return test_harness(test_body, "load_unaligned_zeropad");
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}
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