1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2021 ARM Limited
4 *
5 * Attempt to change the streaming SVE vector length in a signal
6 * handler, this is not supported and is expected to segfault.
7 */
8
9#include <signal.h>
10#include <ucontext.h>
11#include <sys/prctl.h>
12
13#include "test_signals_utils.h"
14#include "testcases.h"
15
16struct fake_sigframe sf;
17static unsigned int vls[SVE_VQ_MAX];
18unsigned int nvls = 0;
19
20static bool sme_get_vls(struct tdescr *td)
21{
22	int vq, vl;
23
24	/*
25	 * Enumerate up to SVE_VQ_MAX vector lengths
26	 */
27	for (vq = SVE_VQ_MAX; vq > 0; --vq) {
28		vl = prctl(PR_SVE_SET_VL, vq * 16);
29		if (vl == -1)
30			return false;
31
32		vl &= PR_SME_VL_LEN_MASK;
33
34		/* Skip missing VLs */
35		vq = sve_vq_from_vl(vl);
36
37		vls[nvls++] = vl;
38	}
39
40	/* We need at least two VLs */
41	if (nvls < 2) {
42		fprintf(stderr, "Only %d VL supported\n", nvls);
43		return false;
44	}
45
46	return true;
47}
48
49static int fake_sigreturn_ssve_change_vl(struct tdescr *td,
50					 siginfo_t *si, ucontext_t *uc)
51{
52	size_t resv_sz, offset;
53	struct _aarch64_ctx *head = GET_SF_RESV_HEAD(sf);
54	struct sve_context *sve;
55
56	/* Get a signal context with a SME ZA frame in it */
57	if (!get_current_context(td, &sf.uc, sizeof(sf.uc)))
58		return 1;
59
60	resv_sz = GET_SF_RESV_SIZE(sf);
61	head = get_header(head, SVE_MAGIC, resv_sz, &offset);
62	if (!head) {
63		fprintf(stderr, "No SVE context\n");
64		return 1;
65	}
66
67	if (head->size != sizeof(struct sve_context)) {
68		fprintf(stderr, "Register data present, aborting\n");
69		return 1;
70	}
71
72	sve = (struct sve_context *)head;
73
74	/* No changes are supported; init left us at minimum VL so go to max */
75	fprintf(stderr, "Attempting to change VL from %d to %d\n",
76		sve->vl, vls[0]);
77	sve->vl = vls[0];
78
79	fake_sigreturn(&sf, sizeof(sf), 0);
80
81	return 1;
82}
83
84struct tdescr tde = {
85	.name = "FAKE_SIGRETURN_SSVE_CHANGE",
86	.descr = "Attempt to change Streaming SVE VL",
87	.feats_required = FEAT_SME,
88	.sig_ok = SIGSEGV,
89	.timeout = 3,
90	.init = sme_get_vls,
91	.run = fake_sigreturn_ssve_change_vl,
92};
93