1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2021 ARM Limited
4  *
5  * Verify that the ZA register context in signal frames is set up as
6  * expected.
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 
16 struct fake_sigframe sf;
17 static unsigned int vls[SVE_VQ_MAX];
18 unsigned int nvls = 0;
19 
20 static 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 one VL */
41 	if (nvls < 1) {
42 		fprintf(stderr, "Only %d VL supported\n", nvls);
43 		return false;
44 	}
45 
46 	return true;
47 }
48 
49 static void setup_za_regs(void)
50 {
51 	/* smstart za; real data is TODO */
52 	asm volatile(".inst 0xd503457f" : : : );
53 }
54 
55 static int do_one_sme_vl(struct tdescr *td, siginfo_t *si, ucontext_t *uc,
56 			 unsigned int vl)
57 {
58 	size_t resv_sz, offset;
59 	struct _aarch64_ctx *head = GET_SF_RESV_HEAD(sf);
60 	struct za_context *za;
61 
62 	fprintf(stderr, "Testing VL %d\n", vl);
63 
64 	if (prctl(PR_SME_SET_VL, vl) != vl) {
65 		fprintf(stderr, "Failed to set VL\n");
66 		return 1;
67 	}
68 
69 	/*
70 	 * Get a signal context which should have a SVE frame and registers
71 	 * in it.
72 	 */
73 	setup_za_regs();
74 	if (!get_current_context(td, &sf.uc))
75 		return 1;
76 
77 	resv_sz = GET_SF_RESV_SIZE(sf);
78 	head = get_header(head, ZA_MAGIC, resv_sz, &offset);
79 	if (!head) {
80 		fprintf(stderr, "No ZA context\n");
81 		return 1;
82 	}
83 
84 	za = (struct za_context *)head;
85 	if (za->vl != vl) {
86 		fprintf(stderr, "Got VL %d, expected %d\n", za->vl, vl);
87 		return 1;
88 	}
89 
90 	/* The actual size validation is done in get_current_context() */
91 	fprintf(stderr, "Got expected size %u and VL %d\n",
92 		head->size, za->vl);
93 
94 	return 0;
95 }
96 
97 static int sme_regs(struct tdescr *td, siginfo_t *si, ucontext_t *uc)
98 {
99 	int i;
100 
101 	for (i = 0; i < nvls; i++) {
102 		/*
103 		 * TODO: the signal test helpers can't currently cope
104 		 * with signal frames bigger than struct sigcontext,
105 		 * skip VLs that will trigger that.
106 		 */
107 		if (vls[i] > 32) {
108 			printf("Skipping VL %u due to stack size\n", vls[i]);
109 			continue;
110 		}
111 
112 		if (do_one_sme_vl(td, si, uc, vls[i]))
113 			return 1;
114 	}
115 
116 	td->pass = 1;
117 
118 	return 0;
119 }
120 
121 struct tdescr tde = {
122 	.name = "ZA register",
123 	.descr = "Check that we get the right ZA registers reported",
124 	.feats_required = FEAT_SME,
125 	.timeout = 3,
126 	.init = sme_get_vls,
127 	.run = sme_regs,
128 };
129