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_FPU_REGS 18 /* Number of non-volatile FP registers */
33 #define FPR14 14 /* First non-volatile FP register to check in f14-31 subset */
34 
35 long tm_signal_self_context_load(pid_t pid, long *gprs, double *fps, vector int *vms, vector int *vss);
36 
37 /* Test only non-volatile registers, i.e. 18 fpr registers from f14 to f31 */
38 static double fps[] = {
39 	/* First context will be set with these values, i.e. non-speculative */
40 	 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
41 	/* Second context will be set with these values, i.e. speculative */
42 	-1,-2,-3,-4,-5,-6,-7,-8,-9,-10,-11,-12,-13,-14,-15,-16,-17,-18
43 };
44 
45 static sig_atomic_t fail, broken;
46 
signal_usr1(int signum,siginfo_t * info,void * uc)47 static void signal_usr1(int signum, siginfo_t *info, void *uc)
48 {
49 	int i;
50 	ucontext_t *ucp = uc;
51 	ucontext_t *tm_ucp = ucp->uc_link;
52 
53 	for (i = 0; i < NV_FPU_REGS; i++) {
54 		/* Check first context. Print all mismatches. */
55 		fail = (ucp->uc_mcontext.fp_regs[FPR14 + i] != fps[i]);
56 		if (fail) {
57 			broken = 1;
58 			printf("FPR%d (1st context) == %g instead of %g (expected)\n",
59 				FPR14 + i, ucp->uc_mcontext.fp_regs[FPR14 + i], fps[i]);
60 		}
61 	}
62 
63 	for (i = 0; i < NV_FPU_REGS; i++) {
64 		/* Check second context. Print all mismatches. */
65 		fail = (tm_ucp->uc_mcontext.fp_regs[FPR14 + i] != fps[NV_FPU_REGS + i]);
66 		if (fail) {
67 			broken = 1;
68 			printf("FPR%d (2nd context) == %g instead of %g (expected)\n",
69 				FPR14 + i, tm_ucp->uc_mcontext.fp_regs[FPR14 + i], fps[NV_FPU_REGS + i]);
70 		}
71 	}
72 }
73 
tm_signal_context_chk_fpu()74 static int tm_signal_context_chk_fpu()
75 {
76 	struct sigaction act;
77 	int i;
78 	long rc;
79 	pid_t pid = getpid();
80 
81 	SKIP_IF(!have_htm());
82 	SKIP_IF(htm_is_synthetic());
83 
84 	act.sa_sigaction = signal_usr1;
85 	sigemptyset(&act.sa_mask);
86 	act.sa_flags = SA_SIGINFO;
87 	if (sigaction(SIGUSR1, &act, NULL) < 0) {
88 		perror("sigaction sigusr1");
89 		exit(1);
90 	}
91 
92 	i = 0;
93 	while (i < MAX_ATTEMPT && !broken) {
94 		/*
95 		 * tm_signal_self_context_load will set both first and second
96 		 * contexts accordingly to the values passed through non-NULL
97 		 * array pointers to it, in that case 'fps', and invoke the
98 		 * signal handler installed for SIGUSR1.
99 		 */
100 		rc = tm_signal_self_context_load(pid, NULL, fps, NULL, NULL);
101 		FAIL_IF(rc != pid);
102 		i++;
103 	}
104 
105 	return (broken);
106 }
107 
main(void)108 int main(void)
109 {
110 	return test_harness(tm_signal_context_chk_fpu, "tm_signal_context_chk_fpu");
111 }
112