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 static union {
17 	ucontext_t uc;
18 	char buf[1024 * 128];
19 } context;
20 static unsigned int vls[SVE_VQ_MAX];
21 unsigned int nvls = 0;
22 
23 static bool sme_get_vls(struct tdescr *td)
24 {
25 	int vq, vl;
26 
27 	/*
28 	 * Enumerate up to SME_VQ_MAX vector lengths
29 	 */
30 	for (vq = SVE_VQ_MAX; vq > 0; --vq) {
31 		vl = prctl(PR_SME_SET_VL, vq * 16);
32 		if (vl == -1)
33 			return false;
34 
35 		vl &= PR_SME_VL_LEN_MASK;
36 
37 		/* Skip missing VLs */
38 		vq = sve_vq_from_vl(vl);
39 
40 		vls[nvls++] = vl;
41 	}
42 
43 	/* We need at least one VL */
44 	if (nvls < 1) {
45 		fprintf(stderr, "Only %d VL supported\n", nvls);
46 		return false;
47 	}
48 
49 	return true;
50 }
51 
52 static void setup_za_regs(void)
53 {
54 	/* smstart za; real data is TODO */
55 	asm volatile(".inst 0xd503457f" : : : );
56 }
57 
58 static char zeros[ZA_SIG_REGS_SIZE(SVE_VQ_MAX)];
59 
60 static int do_one_sme_vl(struct tdescr *td, siginfo_t *si, ucontext_t *uc,
61 			 unsigned int vl)
62 {
63 	size_t offset;
64 	struct _aarch64_ctx *head = GET_BUF_RESV_HEAD(context);
65 	struct za_context *za;
66 
67 	fprintf(stderr, "Testing VL %d\n", vl);
68 
69 	if (prctl(PR_SME_SET_VL, vl) != vl) {
70 		fprintf(stderr, "Failed to set VL\n");
71 		return 1;
72 	}
73 
74 	/*
75 	 * Get a signal context which should have a SVE frame and registers
76 	 * in it.
77 	 */
78 	setup_za_regs();
79 	if (!get_current_context(td, &context.uc, sizeof(context)))
80 		return 1;
81 
82 	head = get_header(head, ZA_MAGIC, GET_BUF_RESV_SIZE(context), &offset);
83 	if (!head) {
84 		fprintf(stderr, "No ZA context\n");
85 		return 1;
86 	}
87 
88 	za = (struct za_context *)head;
89 	if (za->vl != vl) {
90 		fprintf(stderr, "Got VL %d, expected %d\n", za->vl, vl);
91 		return 1;
92 	}
93 
94 	if (head->size != ZA_SIG_CONTEXT_SIZE(sve_vq_from_vl(vl))) {
95 		fprintf(stderr, "ZA context size %u, expected %lu\n",
96 			head->size, ZA_SIG_CONTEXT_SIZE(sve_vq_from_vl(vl)));
97 		return 1;
98 	}
99 
100 	fprintf(stderr, "Got expected size %u and VL %d\n",
101 		head->size, za->vl);
102 
103 	/* We didn't load any data into ZA so it should be all zeros */
104 	if (memcmp(zeros, (char *)za + ZA_SIG_REGS_OFFSET,
105 		   ZA_SIG_REGS_SIZE(sve_vq_from_vl(za->vl))) != 0) {
106 		fprintf(stderr, "ZA data invalid\n");
107 		return 1;
108 	}
109 
110 	return 0;
111 }
112 
113 static int sme_regs(struct tdescr *td, siginfo_t *si, ucontext_t *uc)
114 {
115 	int i;
116 
117 	for (i = 0; i < nvls; i++) {
118 		if (do_one_sme_vl(td, si, uc, vls[i]))
119 			return 1;
120 	}
121 
122 	td->pass = 1;
123 
124 	return 0;
125 }
126 
127 struct tdescr tde = {
128 	.name = "ZA register",
129 	.descr = "Check that we get the right ZA registers reported",
130 	.feats_required = FEAT_SME,
131 	.timeout = 3,
132 	.init = sme_get_vls,
133 	.run = sme_regs,
134 };
135