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 <string.h>
23 #include <signal.h>
24 #include <unistd.h>
25 
26 #include <altivec.h>
27 
28 #include "utils.h"
29 #include "tm.h"
30 
31 #define MAX_ATTEMPT 500000
32 
33 #define NV_VMX_REGS 12 /* Number of non-volatile VMX registers */
34 #define VMX20 20 /* First non-volatile register to check in vr20-31 subset */
35 
36 long tm_signal_self_context_load(pid_t pid, long *gprs, double *fps, vector int *vms, vector int *vss);
37 
38 static sig_atomic_t fail, broken;
39 
40 /* Test only non-volatile registers, i.e. 12 vmx registers from vr20 to vr31 */
41 vector int vms[] = {
42 	/* First context will be set with these values, i.e. non-speculative */
43 	/* VMX20     ,  VMX21      , ... */
44 	{ 1, 2, 3, 4},{ 5, 6, 7, 8},{ 9,10,11,12},
45 	{13,14,15,16},{17,18,19,20},{21,22,23,24},
46 	{25,26,27,28},{29,30,31,32},{33,34,35,36},
47 	{37,38,39,40},{41,42,43,44},{45,46,47,48},
48 	/* Second context will be set with these values, i.e. speculative */
49 	/* VMX20        , VMX21            , ... */
50 	{ -1, -2, -3, -4},{ -5, -6, -7, -8},{ -9,-10,-11,-12},
51 	{-13,-14,-15,-16},{-17,-18,-19,-20},{-21,-22,-23,-24},
52 	{-25,-26,-27,-28},{-29,-30,-31,-32},{-33,-34,-35,-36},
53 	{-37,-38,-39,-40},{-41,-42,-43,-44},{-45,-46,-47,-48}
54 };
55 
signal_usr1(int signum,siginfo_t * info,void * uc)56 static void signal_usr1(int signum, siginfo_t *info, void *uc)
57 {
58 	int i, j;
59 	ucontext_t *ucp = uc;
60 	ucontext_t *tm_ucp = ucp->uc_link;
61 
62 	for (i = 0; i < NV_VMX_REGS; i++) {
63 		/* Check first context. Print all mismatches. */
64 		fail = memcmp(ucp->uc_mcontext.v_regs->vrregs[VMX20 + i],
65 				&vms[i], sizeof(vector int));
66 		if (fail) {
67 			broken = 1;
68 			printf("VMX%d (1st context) == 0x", VMX20 + i);
69 			/* Print actual value in first context. */
70 			for (j = 0; j < 4; j++)
71 				printf("%08x", ucp->uc_mcontext.v_regs->vrregs[VMX20 + i][j]);
72 			printf(" instead of 0x");
73 			/* Print expected value. */
74 			for (j = 0; j < 4; j++)
75 				printf("%08x", vms[i][j]);
76 			printf(" (expected)\n");
77 		}
78 	}
79 
80 	for (i = 0; i < NV_VMX_REGS; i++)  {
81 		/* Check second context. Print all mismatches. */
82 		fail = memcmp(tm_ucp->uc_mcontext.v_regs->vrregs[VMX20 + i],
83 				&vms[NV_VMX_REGS + i], sizeof (vector int));
84 		if (fail) {
85 			broken = 1;
86 			printf("VMX%d (2nd context) == 0x", NV_VMX_REGS + i);
87 			/* Print actual value in second context. */
88 			for (j = 0; j < 4; j++)
89 				printf("%08x", tm_ucp->uc_mcontext.v_regs->vrregs[VMX20 + i][j]);
90 			printf(" instead of 0x");
91 			/* Print expected value. */
92 			for (j = 0; j < 4; j++)
93 				printf("%08x", vms[NV_VMX_REGS + i][j]);
94 			printf(" (expected)\n");
95 		}
96 	}
97 }
98 
tm_signal_context_chk()99 static int tm_signal_context_chk()
100 {
101 	struct sigaction act;
102 	int i;
103 	long rc;
104 	pid_t pid = getpid();
105 
106 	SKIP_IF(!have_htm());
107 	SKIP_IF(htm_is_synthetic());
108 
109 	act.sa_sigaction = signal_usr1;
110 	sigemptyset(&act.sa_mask);
111 	act.sa_flags = SA_SIGINFO;
112 	if (sigaction(SIGUSR1, &act, NULL) < 0) {
113 		perror("sigaction sigusr1");
114 		exit(1);
115 	}
116 
117 	i = 0;
118 	while (i < MAX_ATTEMPT && !broken) {
119 		/*
120 		 * tm_signal_self_context_load will set both first and second
121 		 * contexts accordingly to the values passed through non-NULL
122 		 * array pointers to it, in that case 'vms', and invoke the
123 		 * signal handler installed for SIGUSR1.
124 		 */
125 		rc = tm_signal_self_context_load(pid, NULL, NULL, vms, NULL);
126 		FAIL_IF(rc != pid);
127 		i++;
128 	}
129 
130 	return (broken);
131 }
132 
main(void)133 int main(void)
134 {
135 	return test_harness(tm_signal_context_chk, "tm_signal_context_chk_vmx");
136 }
137