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
37long tm_signal_self_context_load(pid_t pid, long *gprs, double *fps, vector int *vms, vector int *vss);
38
39static sig_atomic_t fail, broken;
40
41/* Test only 12 vsx registers from vsr20 to vsr31 */
42vector 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
57static 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
148static 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	SKIP_IF(htm_is_synthetic());
157
158	act.sa_sigaction = signal_usr1;
159	sigemptyset(&act.sa_mask);
160	act.sa_flags = SA_SIGINFO;
161	if (sigaction(SIGUSR1, &act, NULL) < 0) {
162		perror("sigaction sigusr1");
163		exit(1);
164	}
165
166	i = 0;
167	while (i < MAX_ATTEMPT && !broken) {
168               /*
169                * tm_signal_self_context_load will set both first and second
170                * contexts accordingly to the values passed through non-NULL
171                * array pointers to it, in that case 'vsxs', and invoke the
172                * signal handler installed for SIGUSR1.
173                */
174		rc = tm_signal_self_context_load(pid, NULL, NULL, NULL, vsxs);
175		FAIL_IF(rc != pid);
176		i++;
177	}
178
179	return (broken);
180}
181
182int main(void)
183{
184	return test_harness(tm_signal_context_chk, "tm_signal_context_chk_vsx");
185}
186