linux/tools/testing/selftests/powerpc/tm/tm-signal-msr-resv.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright 2015, Michael Neuling, IBM Corp.
   4 *
   5 * Test the kernel's signal return code to ensure that it doesn't
   6 * crash when both the transactional and suspend MSR bits are set in
   7 * the signal context.
   8 *
   9 * For this test, we send ourselves a SIGUSR1.  In the SIGUSR1 handler
  10 * we modify the signal context to set both MSR TM S and T bits (which
  11 * is "reserved" by the PowerISA). When we return from the signal
  12 * handler (implicit sigreturn), the kernel should detect reserved MSR
  13 * value and send us with a SIGSEGV.
  14 */
  15
  16#include <stdlib.h>
  17#include <stdio.h>
  18#include <signal.h>
  19#include <unistd.h>
  20
  21#include "utils.h"
  22#include "tm.h"
  23
  24int segv_expected = 0;
  25
  26void signal_segv(int signum)
  27{
  28        if (segv_expected && (signum == SIGSEGV))
  29                _exit(0);
  30        _exit(1);
  31}
  32
  33void signal_usr1(int signum, siginfo_t *info, void *uc)
  34{
  35        ucontext_t *ucp = uc;
  36
  37        /* Link tm checkpointed context to normal context */
  38        ucp->uc_link = ucp;
  39        /* Set all TM bits so that the context is now invalid */
  40#ifdef __powerpc64__
  41        ucp->uc_mcontext.gp_regs[PT_MSR] |= (7ULL << 32);
  42#else
  43        ucp->uc_mcontext.uc_regs->gregs[PT_MSR] |= (7ULL);
  44#endif
  45        /* Should segv on return becuase of invalid context */
  46        segv_expected = 1;
  47}
  48
  49int tm_signal_msr_resv()
  50{
  51        struct sigaction act;
  52
  53        SKIP_IF(!have_htm());
  54
  55        act.sa_sigaction = signal_usr1;
  56        sigemptyset(&act.sa_mask);
  57        act.sa_flags = SA_SIGINFO;
  58        if (sigaction(SIGUSR1, &act, NULL) < 0) {
  59                perror("sigaction sigusr1");
  60                exit(1);
  61        }
  62        if (signal(SIGSEGV, signal_segv) == SIG_ERR)
  63                exit(1);
  64
  65        raise(SIGUSR1);
  66
  67        /* We shouldn't get here as we exit in the segv handler */
  68        return 1;
  69}
  70
  71int main(void)
  72{
  73        return test_harness(tm_signal_msr_resv, "tm_signal_msr_resv");
  74}
  75