1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2022 ARM Limited
4  *
5  * Verify that the TPIDR2 register context in signal frames is set up as
6  * expected.
7  */
8 
9 #include <signal.h>
10 #include <ucontext.h>
11 #include <sys/auxv.h>
12 #include <sys/prctl.h>
13 #include <unistd.h>
14 #include <asm/sigcontext.h>
15 
16 #include "test_signals_utils.h"
17 #include "testcases.h"
18 
19 static union {
20 	ucontext_t uc;
21 	char buf[1024 * 128];
22 } context;
23 
24 #define SYS_TPIDR2 "S3_3_C13_C0_5"
25 
26 static uint64_t get_tpidr2(void)
27 {
28 	uint64_t val;
29 
30 	asm volatile (
31 		"mrs	%0, " SYS_TPIDR2 "\n"
32 		: "=r"(val)
33 		:
34 		: "cc");
35 
36 	return val;
37 }
38 
39 int tpidr2_present(struct tdescr *td, siginfo_t *si, ucontext_t *uc)
40 {
41 	struct _aarch64_ctx *head = GET_BUF_RESV_HEAD(context);
42 	struct tpidr2_context *tpidr2_ctx;
43 	size_t offset;
44 	bool in_sigframe;
45 	bool have_sme;
46 	__u64 orig_tpidr2;
47 
48 	have_sme = getauxval(AT_HWCAP2) & HWCAP2_SME;
49 	if (have_sme)
50 		orig_tpidr2 = get_tpidr2();
51 
52 	if (!get_current_context(td, &context.uc, sizeof(context)))
53 		return 1;
54 
55 	tpidr2_ctx = (struct tpidr2_context *)
56 		get_header(head, TPIDR2_MAGIC, td->live_sz, &offset);
57 
58 	in_sigframe = tpidr2_ctx != NULL;
59 
60 	fprintf(stderr, "TPIDR2 sigframe %s on system %s SME\n",
61 		in_sigframe ? "present" : "absent",
62 		have_sme ? "with" : "without");
63 
64 	td->pass = (in_sigframe == have_sme);
65 
66 	/*
67 	 * Check that the value we read back was the one present at
68 	 * the time that the signal was triggered.  TPIDR2 is owned by
69 	 * libc so we can't safely choose the value and it is possible
70 	 * that we may need to revisit this in future if something
71 	 * starts deciding to set a new TPIDR2 between us reading and
72 	 * the signal.
73 	 */
74 	if (have_sme && tpidr2_ctx) {
75 		if (tpidr2_ctx->tpidr2 != orig_tpidr2) {
76 			fprintf(stderr, "TPIDR2 in frame is %llx, was %llx\n",
77 				tpidr2_ctx->tpidr2, orig_tpidr2);
78 			td->pass = false;
79 		}
80 	}
81 
82 	return 0;
83 }
84 
85 struct tdescr tde = {
86 	.name = "TPIDR2",
87 	.descr = "Validate that TPIDR2 is present as expected",
88 	.timeout = 3,
89 	.run = tpidr2_present,
90 };
91