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
35long tm_signal_self_context_load(pid_t pid, long *gprs, double *fps, vector int *vms, vector int *vss);
36
37static sig_atomic_t fail, broken;
38
39/* Test only non-volatile general purpose registers, i.e. r14-r31 */
40static 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
49static 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
76static 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	SKIP_IF(htm_is_synthetic());
85
86	act.sa_sigaction = signal_usr1;
87	sigemptyset(&act.sa_mask);
88	act.sa_flags = SA_SIGINFO;
89	if (sigaction(SIGUSR1, &act, NULL) < 0) {
90		perror("sigaction sigusr1");
91		exit(1);
92	}
93
94	i = 0;
95	while (i < MAX_ATTEMPT && !broken) {
96                /*
97                 * tm_signal_self_context_load will set both first and second
98                 * contexts accordingly to the values passed through non-NULL
99                 * array pointers to it, in that case 'gprs', and invoke the
100                 * signal handler installed for SIGUSR1.
101                 */
102		rc = tm_signal_self_context_load(pid, gprs, NULL, NULL, NULL);
103		FAIL_IF(rc != pid);
104		i++;
105	}
106
107	return broken;
108}
109
110int main(void)
111{
112	return test_harness(tm_signal_context_chk_gpr, "tm_signal_context_chk_gpr");
113}
114