xref: /linux/tools/testing/selftests/kvm/aarch64/debug-exceptions.c (revision dec1c62e91ba268ab2a6e339d4d7a59287d5eba1)
1 // SPDX-License-Identifier: GPL-2.0
2 #include <test_util.h>
3 #include <kvm_util.h>
4 #include <processor.h>
5 
6 #define VCPU_ID 0
7 
8 #define MDSCR_KDE	(1 << 13)
9 #define MDSCR_MDE	(1 << 15)
10 #define MDSCR_SS	(1 << 0)
11 
12 #define DBGBCR_LEN8	(0xff << 5)
13 #define DBGBCR_EXEC	(0x0 << 3)
14 #define DBGBCR_EL1	(0x1 << 1)
15 #define DBGBCR_E	(0x1 << 0)
16 
17 #define DBGWCR_LEN8	(0xff << 5)
18 #define DBGWCR_RD	(0x1 << 3)
19 #define DBGWCR_WR	(0x2 << 3)
20 #define DBGWCR_EL1	(0x1 << 1)
21 #define DBGWCR_E	(0x1 << 0)
22 
23 #define SPSR_D		(1 << 9)
24 #define SPSR_SS		(1 << 21)
25 
26 extern unsigned char sw_bp, sw_bp2, hw_bp, hw_bp2, bp_svc, bp_brk, hw_wp, ss_start;
27 static volatile uint64_t sw_bp_addr, hw_bp_addr;
28 static volatile uint64_t wp_addr, wp_data_addr;
29 static volatile uint64_t svc_addr;
30 static volatile uint64_t ss_addr[4], ss_idx;
31 #define  PC(v)  ((uint64_t)&(v))
32 
33 static void reset_debug_state(void)
34 {
35 	asm volatile("msr daifset, #8");
36 
37 	write_sysreg(0, osdlr_el1);
38 	write_sysreg(0, oslar_el1);
39 	isb();
40 
41 	write_sysreg(0, mdscr_el1);
42 	/* This test only uses the first bp and wp slot. */
43 	write_sysreg(0, dbgbvr0_el1);
44 	write_sysreg(0, dbgbcr0_el1);
45 	write_sysreg(0, dbgwcr0_el1);
46 	write_sysreg(0, dbgwvr0_el1);
47 	isb();
48 }
49 
50 static void enable_os_lock(void)
51 {
52 	write_sysreg(1, oslar_el1);
53 	isb();
54 
55 	GUEST_ASSERT(read_sysreg(oslsr_el1) & 2);
56 }
57 
58 static void install_wp(uint64_t addr)
59 {
60 	uint32_t wcr;
61 	uint32_t mdscr;
62 
63 	wcr = DBGWCR_LEN8 | DBGWCR_RD | DBGWCR_WR | DBGWCR_EL1 | DBGWCR_E;
64 	write_sysreg(wcr, dbgwcr0_el1);
65 	write_sysreg(addr, dbgwvr0_el1);
66 	isb();
67 
68 	asm volatile("msr daifclr, #8");
69 
70 	mdscr = read_sysreg(mdscr_el1) | MDSCR_KDE | MDSCR_MDE;
71 	write_sysreg(mdscr, mdscr_el1);
72 	isb();
73 }
74 
75 static void install_hw_bp(uint64_t addr)
76 {
77 	uint32_t bcr;
78 	uint32_t mdscr;
79 
80 	bcr = DBGBCR_LEN8 | DBGBCR_EXEC | DBGBCR_EL1 | DBGBCR_E;
81 	write_sysreg(bcr, dbgbcr0_el1);
82 	write_sysreg(addr, dbgbvr0_el1);
83 	isb();
84 
85 	asm volatile("msr daifclr, #8");
86 
87 	mdscr = read_sysreg(mdscr_el1) | MDSCR_KDE | MDSCR_MDE;
88 	write_sysreg(mdscr, mdscr_el1);
89 	isb();
90 }
91 
92 static void install_ss(void)
93 {
94 	uint32_t mdscr;
95 
96 	asm volatile("msr daifclr, #8");
97 
98 	mdscr = read_sysreg(mdscr_el1) | MDSCR_KDE | MDSCR_SS;
99 	write_sysreg(mdscr, mdscr_el1);
100 	isb();
101 }
102 
103 static volatile char write_data;
104 
105 static void guest_code(void)
106 {
107 	GUEST_SYNC(0);
108 
109 	/* Software-breakpoint */
110 	reset_debug_state();
111 	asm volatile("sw_bp: brk #0");
112 	GUEST_ASSERT_EQ(sw_bp_addr, PC(sw_bp));
113 
114 	GUEST_SYNC(1);
115 
116 	/* Hardware-breakpoint */
117 	reset_debug_state();
118 	install_hw_bp(PC(hw_bp));
119 	asm volatile("hw_bp: nop");
120 	GUEST_ASSERT_EQ(hw_bp_addr, PC(hw_bp));
121 
122 	GUEST_SYNC(2);
123 
124 	/* Hardware-breakpoint + svc */
125 	reset_debug_state();
126 	install_hw_bp(PC(bp_svc));
127 	asm volatile("bp_svc: svc #0");
128 	GUEST_ASSERT_EQ(hw_bp_addr, PC(bp_svc));
129 	GUEST_ASSERT_EQ(svc_addr, PC(bp_svc) + 4);
130 
131 	GUEST_SYNC(3);
132 
133 	/* Hardware-breakpoint + software-breakpoint */
134 	reset_debug_state();
135 	install_hw_bp(PC(bp_brk));
136 	asm volatile("bp_brk: brk #0");
137 	GUEST_ASSERT_EQ(sw_bp_addr, PC(bp_brk));
138 	GUEST_ASSERT_EQ(hw_bp_addr, PC(bp_brk));
139 
140 	GUEST_SYNC(4);
141 
142 	/* Watchpoint */
143 	reset_debug_state();
144 	install_wp(PC(write_data));
145 	write_data = 'x';
146 	GUEST_ASSERT_EQ(write_data, 'x');
147 	GUEST_ASSERT_EQ(wp_data_addr, PC(write_data));
148 
149 	GUEST_SYNC(5);
150 
151 	/* Single-step */
152 	reset_debug_state();
153 	install_ss();
154 	ss_idx = 0;
155 	asm volatile("ss_start:\n"
156 		     "mrs x0, esr_el1\n"
157 		     "add x0, x0, #1\n"
158 		     "msr daifset, #8\n"
159 		     : : : "x0");
160 	GUEST_ASSERT_EQ(ss_addr[0], PC(ss_start));
161 	GUEST_ASSERT_EQ(ss_addr[1], PC(ss_start) + 4);
162 	GUEST_ASSERT_EQ(ss_addr[2], PC(ss_start) + 8);
163 
164 	GUEST_SYNC(6);
165 
166 	/* OS Lock does not block software-breakpoint */
167 	reset_debug_state();
168 	enable_os_lock();
169 	sw_bp_addr = 0;
170 	asm volatile("sw_bp2: brk #0");
171 	GUEST_ASSERT_EQ(sw_bp_addr, PC(sw_bp2));
172 
173 	GUEST_SYNC(7);
174 
175 	/* OS Lock blocking hardware-breakpoint */
176 	reset_debug_state();
177 	enable_os_lock();
178 	install_hw_bp(PC(hw_bp2));
179 	hw_bp_addr = 0;
180 	asm volatile("hw_bp2: nop");
181 	GUEST_ASSERT_EQ(hw_bp_addr, 0);
182 
183 	GUEST_SYNC(8);
184 
185 	/* OS Lock blocking watchpoint */
186 	reset_debug_state();
187 	enable_os_lock();
188 	write_data = '\0';
189 	wp_data_addr = 0;
190 	install_wp(PC(write_data));
191 	write_data = 'x';
192 	GUEST_ASSERT_EQ(write_data, 'x');
193 	GUEST_ASSERT_EQ(wp_data_addr, 0);
194 
195 	GUEST_SYNC(9);
196 
197 	/* OS Lock blocking single-step */
198 	reset_debug_state();
199 	enable_os_lock();
200 	ss_addr[0] = 0;
201 	install_ss();
202 	ss_idx = 0;
203 	asm volatile("mrs x0, esr_el1\n\t"
204 		     "add x0, x0, #1\n\t"
205 		     "msr daifset, #8\n\t"
206 		     : : : "x0");
207 	GUEST_ASSERT_EQ(ss_addr[0], 0);
208 
209 	GUEST_DONE();
210 }
211 
212 static void guest_sw_bp_handler(struct ex_regs *regs)
213 {
214 	sw_bp_addr = regs->pc;
215 	regs->pc += 4;
216 }
217 
218 static void guest_hw_bp_handler(struct ex_regs *regs)
219 {
220 	hw_bp_addr = regs->pc;
221 	regs->pstate |= SPSR_D;
222 }
223 
224 static void guest_wp_handler(struct ex_regs *regs)
225 {
226 	wp_data_addr = read_sysreg(far_el1);
227 	wp_addr = regs->pc;
228 	regs->pstate |= SPSR_D;
229 }
230 
231 static void guest_ss_handler(struct ex_regs *regs)
232 {
233 	GUEST_ASSERT_1(ss_idx < 4, ss_idx);
234 	ss_addr[ss_idx++] = regs->pc;
235 	regs->pstate |= SPSR_SS;
236 }
237 
238 static void guest_svc_handler(struct ex_regs *regs)
239 {
240 	svc_addr = regs->pc;
241 }
242 
243 static int debug_version(struct kvm_vm *vm)
244 {
245 	uint64_t id_aa64dfr0;
246 
247 	get_reg(vm, VCPU_ID, KVM_ARM64_SYS_REG(SYS_ID_AA64DFR0_EL1), &id_aa64dfr0);
248 	return id_aa64dfr0 & 0xf;
249 }
250 
251 int main(int argc, char *argv[])
252 {
253 	struct kvm_vm *vm;
254 	struct ucall uc;
255 	int stage;
256 
257 	vm = vm_create_default(VCPU_ID, 0, guest_code);
258 	ucall_init(vm, NULL);
259 
260 	vm_init_descriptor_tables(vm);
261 	vcpu_init_descriptor_tables(vm, VCPU_ID);
262 
263 	if (debug_version(vm) < 6) {
264 		print_skip("Armv8 debug architecture not supported.");
265 		kvm_vm_free(vm);
266 		exit(KSFT_SKIP);
267 	}
268 
269 	vm_install_sync_handler(vm, VECTOR_SYNC_CURRENT,
270 				ESR_EC_BRK_INS, guest_sw_bp_handler);
271 	vm_install_sync_handler(vm, VECTOR_SYNC_CURRENT,
272 				ESR_EC_HW_BP_CURRENT, guest_hw_bp_handler);
273 	vm_install_sync_handler(vm, VECTOR_SYNC_CURRENT,
274 				ESR_EC_WP_CURRENT, guest_wp_handler);
275 	vm_install_sync_handler(vm, VECTOR_SYNC_CURRENT,
276 				ESR_EC_SSTEP_CURRENT, guest_ss_handler);
277 	vm_install_sync_handler(vm, VECTOR_SYNC_CURRENT,
278 				ESR_EC_SVC64, guest_svc_handler);
279 
280 	for (stage = 0; stage < 11; stage++) {
281 		vcpu_run(vm, VCPU_ID);
282 
283 		switch (get_ucall(vm, VCPU_ID, &uc)) {
284 		case UCALL_SYNC:
285 			TEST_ASSERT(uc.args[1] == stage,
286 				"Stage %d: Unexpected sync ucall, got %lx",
287 				stage, (ulong)uc.args[1]);
288 			break;
289 		case UCALL_ABORT:
290 			TEST_FAIL("%s at %s:%ld\n\tvalues: %#lx, %#lx",
291 				(const char *)uc.args[0],
292 				__FILE__, uc.args[1], uc.args[2], uc.args[3]);
293 			break;
294 		case UCALL_DONE:
295 			goto done;
296 		default:
297 			TEST_FAIL("Unknown ucall %lu", uc.cmd);
298 		}
299 	}
300 
301 done:
302 	kvm_vm_free(vm);
303 	return 0;
304 }
305