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_VSX_REGS 12 /* Number of VSX registers to check. */
34 #define VSX20 20 /* First VSX register to check in vsr20-vsr31 subset */
35 #define FPR20 20 /* FPR20 overlaps VSX20 most significant doubleword */
36
37 long tm_signal_self_context_load(pid_t pid, long *gprs, double *fps, vector int *vms, vector int *vss);
38
39 static sig_atomic_t fail, broken;
40
41 /* Test only 12 vsx registers from vsr20 to vsr31 */
42 vector int vsxs[] = {
43 /* First context will be set with these values, i.e. non-speculative */
44 /* VSX20 , VSX21 , ... */
45 { 1, 2, 3, 4},{ 5, 6, 7, 8},{ 9,10,11,12},
46 {13,14,15,16},{17,18,19,20},{21,22,23,24},
47 {25,26,27,28},{29,30,31,32},{33,34,35,36},
48 {37,38,39,40},{41,42,43,44},{45,46,47,48},
49 /* Second context will be set with these values, i.e. speculative */
50 /* VSX20 , VSX21 , ... */
51 {-1, -2, -3, -4 },{-5, -6, -7, -8 },{-9, -10,-11,-12},
52 {-13,-14,-15,-16},{-17,-18,-19,-20},{-21,-22,-23,-24},
53 {-25,-26,-27,-28},{-29,-30,-31,-32},{-33,-34,-35,-36},
54 {-37,-38,-39,-40},{-41,-42,-43,-44},{-45,-46,-47,-48}
55 };
56
57 static void signal_usr1(int signum, siginfo_t *info, void *uc)
58 {
59 int i, j;
60 uint8_t vsx[sizeof(vector int)];
61 uint8_t vsx_tm[sizeof(vector int)];
62 ucontext_t *ucp = uc;
63 ucontext_t *tm_ucp = ucp->uc_link;
64
65 /*
66 * FP registers and VMX registers overlap the VSX registers.
67 *
68 * FP registers (f0-31) overlap the most significant 64 bits of VSX
69 * registers vsr0-31, whilst VMX registers vr0-31, being 128-bit like
70 * the VSX registers, overlap fully the other half of VSX registers,
71 * i.e. vr0-31 overlaps fully vsr32-63.
72 *
73 * Due to compatibility and historical reasons (VMX/Altivec support
74 * appeared first on the architecture), VMX registers vr0-31 (so VSX
75 * half vsr32-63 too) are stored right after the v_regs pointer, in an
76 * area allocated for 'vmx_reverse' array (please see
77 * arch/powerpc/include/uapi/asm/sigcontext.h for details about the
78 * mcontext_t structure on Power).
79 *
80 * The other VSX half (vsr0-31) is hence stored below vr0-31/vsr32-63
81 * registers, but only the least significant 64 bits of vsr0-31. The
82 * most significant 64 bits of vsr0-31 (f0-31), as it overlaps the FP
83 * registers, is kept in fp_regs.
84 *
85 * v_regs is a 16 byte aligned pointer at the start of vmx_reserve
86 * (vmx_reserve may or may not be 16 aligned) where the v_regs structure
87 * exists, so v_regs points to where vr0-31 / vsr32-63 registers are
88 * fully stored. Since v_regs type is elf_vrregset_t, v_regs + 1
89 * skips all the slots used to store vr0-31 / vsr32-64 and points to
90 * part of one VSX half, i.e. v_regs + 1 points to the least significant
91 * 64 bits of vsr0-31. The other part of this half (the most significant
92 * part of vsr0-31) is stored in fp_regs.
93 *
94 */
95 /* Get pointer to least significant doubleword of vsr0-31 */
96 long *vsx_ptr = (long *)(ucp->uc_mcontext.v_regs + 1);
97 long *tm_vsx_ptr = (long *)(tm_ucp->uc_mcontext.v_regs + 1);
98
99 /* Check first context. Print all mismatches. */
100 for (i = 0; i < NV_VSX_REGS; i++) {
101 /*
102 * Copy VSX most significant doubleword from fp_regs and
103 * copy VSX least significant one from 64-bit slots below
104 * saved VMX registers.
105 */
106 memcpy(vsx, &ucp->uc_mcontext.fp_regs[FPR20 + i], 8);
107 memcpy(vsx + 8, &vsx_ptr[VSX20 + i], 8);
108
109 fail = memcmp(vsx, &vsxs[i], sizeof(vector int));
110
111 if (fail) {
112 broken = 1;
113 printf("VSX%d (1st context) == 0x", VSX20 + i);
114 for (j = 0; j < 16; j++)
115 printf("%02x", vsx[j]);
116 printf(" instead of 0x");
117 for (j = 0; j < 4; j++)
118 printf("%08x", vsxs[i][j]);
119 printf(" (expected)\n");
120 }
121 }
122
123 /* Check second context. Print all mismatches. */
124 for (i = 0; i < NV_VSX_REGS; i++) {
125 /*
126 * Copy VSX most significant doubleword from fp_regs and
127 * copy VSX least significant one from 64-bit slots below
128 * saved VMX registers.
129 */
130 memcpy(vsx_tm, &tm_ucp->uc_mcontext.fp_regs[FPR20 + i], 8);
131 memcpy(vsx_tm + 8, &tm_vsx_ptr[VSX20 + i], 8);
132
133 fail = memcmp(vsx_tm, &vsxs[NV_VSX_REGS + i], sizeof(vector int));
134
135 if (fail) {
136 broken = 1;
137 printf("VSX%d (2nd context) == 0x", VSX20 + i);
138 for (j = 0; j < 16; j++)
139 printf("%02x", vsx_tm[j]);
140 printf(" instead of 0x");
141 for (j = 0; j < 4; j++)
142 printf("%08x", vsxs[NV_VSX_REGS + i][j]);
143 printf("(expected)\n");
144 }
145 }
146 }
147
148 static int tm_signal_context_chk()
149 {
150 struct sigaction act;
151 int i;
152 long rc;
153 pid_t pid = getpid();
154
155 SKIP_IF(!have_htm());
156
157 act.sa_sigaction = signal_usr1;
158 sigemptyset(&act.sa_mask);
159 act.sa_flags = SA_SIGINFO;
160 if (sigaction(SIGUSR1, &act, NULL) < 0) {
161 perror("sigaction sigusr1");
162 exit(1);
163 }
164
165 i = 0;
166 while (i < MAX_ATTEMPT && !broken) {
167 /*
168 * tm_signal_self_context_load will set both first and second
169 * contexts accordingly to the values passed through non-NULL
170 * array pointers to it, in that case 'vsxs', and invoke the
171 * signal handler installed for SIGUSR1.
172 */
173 rc = tm_signal_self_context_load(pid, NULL, NULL, NULL, vsxs);
174 FAIL_IF(rc != pid);
175 i++;
176 }
177
178 return (broken);
179 }
180
181 int main(void)
182 {
183 return test_harness(tm_signal_context_chk, "tm_signal_context_chk_vsx");
184 }