1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2021 ARM Limited
4 *
5 * Attempt to change the SVE vector length in a signal hander, this is not
6 * supported and is expected to segfault.
7 */
8
9#include <kselftest.h>
10#include <signal.h>
11#include <ucontext.h>
12#include <sys/prctl.h>
13
14#include "test_signals_utils.h"
15#include "testcases.h"
16
17struct fake_sigframe sf;
18static unsigned int vls[SVE_VQ_MAX];
19unsigned int nvls = 0;
20
21static bool sve_get_vls(struct tdescr *td)
22{
23	int vq, vl;
24
25	/*
26	 * Enumerate up to SVE_VQ_MAX vector lengths
27	 */
28	for (vq = SVE_VQ_MAX; vq > 0; --vq) {
29		vl = prctl(PR_SVE_SET_VL, vq * 16);
30		if (vl == -1)
31			return false;
32
33		vl &= PR_SVE_VL_LEN_MASK;
34
35		/* Skip missing VLs */
36		vq = sve_vq_from_vl(vl);
37
38		vls[nvls++] = vl;
39	}
40
41	/* We need at least two VLs */
42	if (nvls < 2) {
43		fprintf(stderr, "Only %d VL supported\n", nvls);
44		td->result = KSFT_SKIP;
45		return false;
46	}
47
48	return true;
49}
50
51static int fake_sigreturn_sve_change_vl(struct tdescr *td,
52					siginfo_t *si, ucontext_t *uc)
53{
54	size_t resv_sz, offset;
55	struct _aarch64_ctx *head = GET_SF_RESV_HEAD(sf);
56	struct sve_context *sve;
57
58	/* Get a signal context with a SVE frame in it */
59	if (!get_current_context(td, &sf.uc, sizeof(sf.uc)))
60		return 1;
61
62	resv_sz = GET_SF_RESV_SIZE(sf);
63	head = get_header(head, SVE_MAGIC, resv_sz, &offset);
64	if (!head) {
65		fprintf(stderr, "No SVE context\n");
66		return 1;
67	}
68
69	if (head->size != sizeof(struct sve_context)) {
70		fprintf(stderr, "SVE register state active, skipping\n");
71		return 1;
72	}
73
74	sve = (struct sve_context *)head;
75
76	/* No changes are supported; init left us at minimum VL so go to max */
77	fprintf(stderr, "Attempting to change VL from %d to %d\n",
78		sve->vl, vls[0]);
79	sve->vl = vls[0];
80
81	fake_sigreturn(&sf, sizeof(sf), 0);
82
83	return 1;
84}
85
86struct tdescr tde = {
87	.name = "FAKE_SIGRETURN_SVE_CHANGE",
88	.descr = "Attempt to change SVE VL",
89	.feats_required = FEAT_SVE,
90	.sig_ok = SIGSEGV,
91	.timeout = 3,
92	.init = sve_get_vls,
93	.run = fake_sigreturn_sve_change_vl,
94};
95