root/tools/testing/selftests/powerpc/alignment/copy_first_unaligned.c

DEFINITIONS

1. signal_action_handler
2. setup_signal_handler
3. test_copy_first_unaligned
4. main

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright 2016, Chris Smart, IBM Corporation.
   4  *
   5  * Calls to copy_first which are not 128-byte aligned should be
   6  * caught and sent a SIGBUS.
   7  */
   8 
   9 #include <signal.h>
  10 #include <string.h>
  11 #include <unistd.h>
  12 #include "utils.h"
  13 #include "instructions.h"
  14 
  15 unsigned int expected_instruction = PPC_INST_COPY_FIRST;
  16 unsigned int instruction_mask = 0xfc2007fe;
  17 
  18 void signal_action_handler(int signal_num, siginfo_t *info, void *ptr)
  19 {
  20         ucontext_t *ctx = ptr;
  21 #ifdef __powerpc64__
  22         unsigned int *pc = (unsigned int *)ctx->uc_mcontext.gp_regs[PT_NIP];
  23 #else
  24         unsigned int *pc = (unsigned int *)ctx->uc_mcontext.uc_regs->gregs[PT_NIP];
  25 #endif
  26 
  27         /*
  28          * Check that the signal was on the correct instruction, using a
  29          * mask because the compiler assigns the register at RB.
  30          */
  31         if ((*pc & instruction_mask) == expected_instruction)
  32                 _exit(0); /* We hit the right instruction */
  33 
  34         _exit(1);
  35 }
  36 
  37 void setup_signal_handler(void)
  38 {
  39         struct sigaction signal_action;
  40 
  41         memset(&signal_action, 0, sizeof(signal_action));
  42         signal_action.sa_sigaction = signal_action_handler;
  43         signal_action.sa_flags = SA_SIGINFO;
  44         sigaction(SIGBUS, &signal_action, NULL);
  45 }
  46 
  47 char cacheline_buf[128] __cacheline_aligned;
  48 
  49 int test_copy_first_unaligned(void)
  50 {
  51         /* Only run this test on a P9 or later */
  52         SKIP_IF(!have_hwcap2(PPC_FEATURE2_ARCH_3_00));
  53 
  54         /* Register our signal handler with SIGBUS */
  55         setup_signal_handler();
  56 
  57         /* +1 makes buf unaligned */
  58         copy_first(cacheline_buf+1);
  59 
  60         /* We should not get here */
  61         return 1;
  62 }
  63 
  64 int main(int argc, char *argv[])
  65 {
  66         return test_harness(test_copy_first_unaligned, "test_copy_first_unaligned");
  67 }