1 /*
2  * Copyright 2015, Michael Neuling, IBM Corp.
3  * Licensed under GPLv2.
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 
24 int segv_expected = 0;
25 
26 void signal_segv(int signum)
27 {
28 	if (segv_expected && (signum == SIGSEGV))
29 		_exit(0);
30 	_exit(1);
31 }
32 
33 void 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 
49 int 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 
71 int main(void)
72 {
73 	return test_harness(tm_signal_msr_resv, "tm_signal_msr_resv");
74 }
75