1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright 2016, Cyril Bur, IBM Corp.
4  *
5  * Test the kernel's signal frame code.
6  *
7  * The kernel sets up two sets of ucontexts if the signal was to be
8  * delivered while the thread was in a transaction (referred too as
9  * first and second contexts).
10  * Expected behaviour is that the checkpointed state is in the user
11  * context passed to the signal handler (first context). The speculated
12  * state can be accessed with the uc_link pointer (second context).
13  *
14  * The rationale for this is that if TM unaware code (which linked
15  * against TM libs) installs a signal handler it will not know of the
16  * speculative nature of the 'live' registers and may infer the wrong
17  * thing.
18  */
19 
20 #include <stdlib.h>
21 #include <stdio.h>
22 #include <signal.h>
23 #include <unistd.h>
24 
25 #include <altivec.h>
26 
27 #include "utils.h"
28 #include "tm.h"
29 
30 #define MAX_ATTEMPT 500000
31 
32 #define NV_GPR_REGS 18 /* Number of non-volatile GPR registers */
33 #define R14 14 /* First non-volatile register to check in r14-r31 subset */
34 
35 long tm_signal_self_context_load(pid_t pid, long *gprs, double *fps, vector int *vms, vector int *vss);
36 
37 static sig_atomic_t fail, broken;
38 
39 /* Test only non-volatile general purpose registers, i.e. r14-r31 */
40 static long gprs[] = {
41 	/* First context will be set with these values, i.e. non-speculative */
42 	/* R14, R15, ... */
43 	 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
44 	/* Second context will be set with these values, i.e. speculative */
45 	/* R14, R15, ... */
46 	-1,-2,-3,-4,-5,-6,-7,-8,-9,-10,-11,-12,-13,-14,-15,-16,-17,-18
47 };
48 
49 static void signal_usr1(int signum, siginfo_t *info, void *uc)
50 {
51 	int i;
52 	ucontext_t *ucp = uc;
53 	ucontext_t *tm_ucp = ucp->uc_link;
54 
55 	/* Check first context. Print all mismatches. */
56 	for (i = 0; i < NV_GPR_REGS; i++) {
57 		fail = (ucp->uc_mcontext.gp_regs[R14 + i] != gprs[i]);
58 		if (fail) {
59 			broken = 1;
60 			printf("GPR%d (1st context) == %lu instead of %lu (expected)\n",
61 				R14 + i, ucp->uc_mcontext.gp_regs[R14 + i], gprs[i]);
62 		}
63 	}
64 
65 	/* Check second context. Print all mismatches. */
66 	for (i = 0; i < NV_GPR_REGS; i++) {
67 		fail = (tm_ucp->uc_mcontext.gp_regs[R14 + i] != gprs[NV_GPR_REGS + i]);
68 		if (fail) {
69 			broken = 1;
70 			printf("GPR%d (2nd context) == %lu instead of %lu (expected)\n",
71 				R14 + i, tm_ucp->uc_mcontext.gp_regs[R14 + i], gprs[NV_GPR_REGS + i]);
72 		}
73 	}
74 }
75 
76 static int tm_signal_context_chk_gpr()
77 {
78 	struct sigaction act;
79 	int i;
80 	long rc;
81 	pid_t pid = getpid();
82 
83 	SKIP_IF(!have_htm());
84 
85 	act.sa_sigaction = signal_usr1;
86 	sigemptyset(&act.sa_mask);
87 	act.sa_flags = SA_SIGINFO;
88 	if (sigaction(SIGUSR1, &act, NULL) < 0) {
89 		perror("sigaction sigusr1");
90 		exit(1);
91 	}
92 
93 	i = 0;
94 	while (i < MAX_ATTEMPT && !broken) {
95                 /*
96                  * tm_signal_self_context_load will set both first and second
97                  * contexts accordingly to the values passed through non-NULL
98                  * array pointers to it, in that case 'gprs', and invoke the
99                  * signal handler installed for SIGUSR1.
100                  */
101 		rc = tm_signal_self_context_load(pid, gprs, NULL, NULL, NULL);
102 		FAIL_IF(rc != pid);
103 		i++;
104 	}
105 
106 	return broken;
107 }
108 
109 int main(void)
110 {
111 	return test_harness(tm_signal_context_chk_gpr, "tm_signal_context_chk_gpr");
112 }
113