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f81ef4a9 WD |
1 | /* |
2 | * This program is free software; you can redistribute it and/or modify | |
3 | * it under the terms of the GNU General Public License version 2 as | |
4 | * published by the Free Software Foundation. | |
5 | * | |
6 | * This program is distributed in the hope that it will be useful, | |
7 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
8 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
9 | * GNU General Public License for more details. | |
10 | * | |
11 | * You should have received a copy of the GNU General Public License | |
12 | * along with this program; if not, write to the Free Software | |
13 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
14 | * | |
15 | * Copyright (C) 2009, 2010 ARM Limited | |
16 | * | |
17 | * Author: Will Deacon <will.deacon@arm.com> | |
18 | */ | |
19 | ||
20 | /* | |
21 | * HW_breakpoint: a unified kernel/user-space hardware breakpoint facility, | |
22 | * using the CPU's debug registers. | |
23 | */ | |
24 | #define pr_fmt(fmt) "hw-breakpoint: " fmt | |
25 | ||
26 | #include <linux/errno.h> | |
7e202696 | 27 | #include <linux/hardirq.h> |
f81ef4a9 WD |
28 | #include <linux/perf_event.h> |
29 | #include <linux/hw_breakpoint.h> | |
30 | #include <linux/smp.h> | |
9a6eb310 | 31 | #include <linux/cpu_pm.h> |
f81ef4a9 WD |
32 | |
33 | #include <asm/cacheflush.h> | |
34 | #include <asm/cputype.h> | |
35 | #include <asm/current.h> | |
36 | #include <asm/hw_breakpoint.h> | |
37 | #include <asm/kdebug.h> | |
f81ef4a9 | 38 | #include <asm/traps.h> |
02051ead | 39 | #include <asm/hardware/coresight.h> |
f81ef4a9 WD |
40 | |
41 | /* Breakpoint currently in use for each BRP. */ | |
42 | static DEFINE_PER_CPU(struct perf_event *, bp_on_reg[ARM_MAX_BRP]); | |
43 | ||
44 | /* Watchpoint currently in use for each WRP. */ | |
45 | static DEFINE_PER_CPU(struct perf_event *, wp_on_reg[ARM_MAX_WRP]); | |
46 | ||
47 | /* Number of BRP/WRP registers on this CPU. */ | |
48 | static int core_num_brps; | |
49 | static int core_num_wrps; | |
50 | ||
51 | /* Debug architecture version. */ | |
52 | static u8 debug_arch; | |
53 | ||
57ba8997 DE |
54 | /* Does debug architecture support OS Save and Restore? */ |
55 | static bool has_ossr; | |
56 | ||
f81ef4a9 WD |
57 | /* Maximum supported watchpoint length. */ |
58 | static u8 max_watchpoint_len; | |
59 | ||
9e962f76 DE |
60 | #define READ_WB_REG_CASE(OP2, M, VAL) \ |
61 | case ((OP2 << 4) + M): \ | |
62 | ARM_DBG_READ(c0, c ## M, OP2, VAL); \ | |
f81ef4a9 WD |
63 | break |
64 | ||
9e962f76 DE |
65 | #define WRITE_WB_REG_CASE(OP2, M, VAL) \ |
66 | case ((OP2 << 4) + M): \ | |
67 | ARM_DBG_WRITE(c0, c ## M, OP2, VAL); \ | |
f81ef4a9 WD |
68 | break |
69 | ||
70 | #define GEN_READ_WB_REG_CASES(OP2, VAL) \ | |
71 | READ_WB_REG_CASE(OP2, 0, VAL); \ | |
72 | READ_WB_REG_CASE(OP2, 1, VAL); \ | |
73 | READ_WB_REG_CASE(OP2, 2, VAL); \ | |
74 | READ_WB_REG_CASE(OP2, 3, VAL); \ | |
75 | READ_WB_REG_CASE(OP2, 4, VAL); \ | |
76 | READ_WB_REG_CASE(OP2, 5, VAL); \ | |
77 | READ_WB_REG_CASE(OP2, 6, VAL); \ | |
78 | READ_WB_REG_CASE(OP2, 7, VAL); \ | |
79 | READ_WB_REG_CASE(OP2, 8, VAL); \ | |
80 | READ_WB_REG_CASE(OP2, 9, VAL); \ | |
81 | READ_WB_REG_CASE(OP2, 10, VAL); \ | |
82 | READ_WB_REG_CASE(OP2, 11, VAL); \ | |
83 | READ_WB_REG_CASE(OP2, 12, VAL); \ | |
84 | READ_WB_REG_CASE(OP2, 13, VAL); \ | |
85 | READ_WB_REG_CASE(OP2, 14, VAL); \ | |
86 | READ_WB_REG_CASE(OP2, 15, VAL) | |
87 | ||
88 | #define GEN_WRITE_WB_REG_CASES(OP2, VAL) \ | |
89 | WRITE_WB_REG_CASE(OP2, 0, VAL); \ | |
90 | WRITE_WB_REG_CASE(OP2, 1, VAL); \ | |
91 | WRITE_WB_REG_CASE(OP2, 2, VAL); \ | |
92 | WRITE_WB_REG_CASE(OP2, 3, VAL); \ | |
93 | WRITE_WB_REG_CASE(OP2, 4, VAL); \ | |
94 | WRITE_WB_REG_CASE(OP2, 5, VAL); \ | |
95 | WRITE_WB_REG_CASE(OP2, 6, VAL); \ | |
96 | WRITE_WB_REG_CASE(OP2, 7, VAL); \ | |
97 | WRITE_WB_REG_CASE(OP2, 8, VAL); \ | |
98 | WRITE_WB_REG_CASE(OP2, 9, VAL); \ | |
99 | WRITE_WB_REG_CASE(OP2, 10, VAL); \ | |
100 | WRITE_WB_REG_CASE(OP2, 11, VAL); \ | |
101 | WRITE_WB_REG_CASE(OP2, 12, VAL); \ | |
102 | WRITE_WB_REG_CASE(OP2, 13, VAL); \ | |
103 | WRITE_WB_REG_CASE(OP2, 14, VAL); \ | |
104 | WRITE_WB_REG_CASE(OP2, 15, VAL) | |
105 | ||
106 | static u32 read_wb_reg(int n) | |
107 | { | |
108 | u32 val = 0; | |
109 | ||
110 | switch (n) { | |
111 | GEN_READ_WB_REG_CASES(ARM_OP2_BVR, val); | |
112 | GEN_READ_WB_REG_CASES(ARM_OP2_BCR, val); | |
113 | GEN_READ_WB_REG_CASES(ARM_OP2_WVR, val); | |
114 | GEN_READ_WB_REG_CASES(ARM_OP2_WCR, val); | |
115 | default: | |
116 | pr_warning("attempt to read from unknown breakpoint " | |
117 | "register %d\n", n); | |
118 | } | |
119 | ||
120 | return val; | |
121 | } | |
122 | ||
123 | static void write_wb_reg(int n, u32 val) | |
124 | { | |
125 | switch (n) { | |
126 | GEN_WRITE_WB_REG_CASES(ARM_OP2_BVR, val); | |
127 | GEN_WRITE_WB_REG_CASES(ARM_OP2_BCR, val); | |
128 | GEN_WRITE_WB_REG_CASES(ARM_OP2_WVR, val); | |
129 | GEN_WRITE_WB_REG_CASES(ARM_OP2_WCR, val); | |
130 | default: | |
131 | pr_warning("attempt to write to unknown breakpoint " | |
132 | "register %d\n", n); | |
133 | } | |
134 | isb(); | |
135 | } | |
136 | ||
0017ff42 WD |
137 | /* Determine debug architecture. */ |
138 | static u8 get_debug_arch(void) | |
139 | { | |
140 | u32 didr; | |
141 | ||
142 | /* Do we implement the extended CPUID interface? */ | |
d1244336 | 143 | if (((read_cpuid_id() >> 16) & 0xf) != 0xf) { |
5ad29ea2 WD |
144 | pr_warn_once("CPUID feature registers not supported. " |
145 | "Assuming v6 debug is present.\n"); | |
0017ff42 | 146 | return ARM_DEBUG_ARCH_V6; |
d1244336 | 147 | } |
0017ff42 | 148 | |
9e962f76 | 149 | ARM_DBG_READ(c0, c0, 0, didr); |
0017ff42 WD |
150 | return (didr >> 16) & 0xf; |
151 | } | |
152 | ||
153 | u8 arch_get_debug_arch(void) | |
154 | { | |
155 | return debug_arch; | |
156 | } | |
157 | ||
66e1cfe6 WD |
158 | static int debug_arch_supported(void) |
159 | { | |
160 | u8 arch = get_debug_arch(); | |
b5d5b8f9 WD |
161 | |
162 | /* We don't support the memory-mapped interface. */ | |
163 | return (arch >= ARM_DEBUG_ARCH_V6 && arch <= ARM_DEBUG_ARCH_V7_ECP14) || | |
164 | arch >= ARM_DEBUG_ARCH_V7_1; | |
66e1cfe6 WD |
165 | } |
166 | ||
bf880114 WD |
167 | /* Can we determine the watchpoint access type from the fsr? */ |
168 | static int debug_exception_updates_fsr(void) | |
169 | { | |
170 | return 0; | |
171 | } | |
172 | ||
c512de95 WD |
173 | /* Determine number of WRP registers available. */ |
174 | static int get_num_wrp_resources(void) | |
175 | { | |
176 | u32 didr; | |
9e962f76 | 177 | ARM_DBG_READ(c0, c0, 0, didr); |
c512de95 WD |
178 | return ((didr >> 28) & 0xf) + 1; |
179 | } | |
180 | ||
181 | /* Determine number of BRP registers available. */ | |
0017ff42 WD |
182 | static int get_num_brp_resources(void) |
183 | { | |
184 | u32 didr; | |
9e962f76 | 185 | ARM_DBG_READ(c0, c0, 0, didr); |
0017ff42 WD |
186 | return ((didr >> 24) & 0xf) + 1; |
187 | } | |
188 | ||
189 | /* Does this core support mismatch breakpoints? */ | |
190 | static int core_has_mismatch_brps(void) | |
191 | { | |
192 | return (get_debug_arch() >= ARM_DEBUG_ARCH_V7_ECP14 && | |
193 | get_num_brp_resources() > 1); | |
194 | } | |
195 | ||
196 | /* Determine number of usable WRPs available. */ | |
197 | static int get_num_wrps(void) | |
198 | { | |
199 | /* | |
c512de95 WD |
200 | * On debug architectures prior to 7.1, when a watchpoint fires, the |
201 | * only way to work out which watchpoint it was is by disassembling | |
202 | * the faulting instruction and working out the address of the memory | |
203 | * access. | |
0017ff42 WD |
204 | * |
205 | * Furthermore, we can only do this if the watchpoint was precise | |
206 | * since imprecise watchpoints prevent us from calculating register | |
207 | * based addresses. | |
208 | * | |
209 | * Providing we have more than 1 breakpoint register, we only report | |
210 | * a single watchpoint register for the time being. This way, we always | |
211 | * know which watchpoint fired. In the future we can either add a | |
212 | * disassembler and address generation emulator, or we can insert a | |
213 | * check to see if the DFAR is set on watchpoint exception entry | |
214 | * [the ARM ARM states that the DFAR is UNKNOWN, but experience shows | |
215 | * that it is set on some implementations]. | |
216 | */ | |
c512de95 WD |
217 | if (get_debug_arch() < ARM_DEBUG_ARCH_V7_1) |
218 | return 1; | |
0017ff42 | 219 | |
c512de95 | 220 | return get_num_wrp_resources(); |
0017ff42 WD |
221 | } |
222 | ||
223 | /* Determine number of usable BRPs available. */ | |
224 | static int get_num_brps(void) | |
225 | { | |
226 | int brps = get_num_brp_resources(); | |
c512de95 | 227 | return core_has_mismatch_brps() ? brps - 1 : brps; |
0017ff42 WD |
228 | } |
229 | ||
f81ef4a9 WD |
230 | /* |
231 | * In order to access the breakpoint/watchpoint control registers, | |
232 | * we must be running in debug monitor mode. Unfortunately, we can | |
233 | * be put into halting debug mode at any time by an external debugger | |
234 | * but there is nothing we can do to prevent that. | |
235 | */ | |
0daa034e WD |
236 | static int monitor_mode_enabled(void) |
237 | { | |
238 | u32 dscr; | |
9e962f76 | 239 | ARM_DBG_READ(c0, c1, 0, dscr); |
0daa034e WD |
240 | return !!(dscr & ARM_DSCR_MDBGEN); |
241 | } | |
242 | ||
f81ef4a9 WD |
243 | static int enable_monitor_mode(void) |
244 | { | |
245 | u32 dscr; | |
9e962f76 | 246 | ARM_DBG_READ(c0, c1, 0, dscr); |
f81ef4a9 | 247 | |
8fbf397c WD |
248 | /* If monitor mode is already enabled, just return. */ |
249 | if (dscr & ARM_DSCR_MDBGEN) | |
250 | goto out; | |
251 | ||
f81ef4a9 | 252 | /* Write to the corresponding DSCR. */ |
8fbf397c | 253 | switch (get_debug_arch()) { |
f81ef4a9 WD |
254 | case ARM_DEBUG_ARCH_V6: |
255 | case ARM_DEBUG_ARCH_V6_1: | |
9e962f76 | 256 | ARM_DBG_WRITE(c0, c1, 0, (dscr | ARM_DSCR_MDBGEN)); |
f81ef4a9 WD |
257 | break; |
258 | case ARM_DEBUG_ARCH_V7_ECP14: | |
b5d5b8f9 | 259 | case ARM_DEBUG_ARCH_V7_1: |
9e962f76 | 260 | ARM_DBG_WRITE(c0, c2, 2, (dscr | ARM_DSCR_MDBGEN)); |
b59a540c | 261 | isb(); |
f81ef4a9 WD |
262 | break; |
263 | default: | |
614bea50 | 264 | return -ENODEV; |
f81ef4a9 WD |
265 | } |
266 | ||
267 | /* Check that the write made it through. */ | |
9e962f76 | 268 | ARM_DBG_READ(c0, c1, 0, dscr); |
f435ab79 WD |
269 | if (!(dscr & ARM_DSCR_MDBGEN)) { |
270 | pr_warn_once("Failed to enable monitor mode on CPU %d.\n", | |
271 | smp_processor_id()); | |
614bea50 | 272 | return -EPERM; |
f435ab79 | 273 | } |
f81ef4a9 WD |
274 | |
275 | out: | |
614bea50 | 276 | return 0; |
f81ef4a9 WD |
277 | } |
278 | ||
8fbf397c WD |
279 | int hw_breakpoint_slots(int type) |
280 | { | |
66e1cfe6 WD |
281 | if (!debug_arch_supported()) |
282 | return 0; | |
283 | ||
8fbf397c WD |
284 | /* |
285 | * We can be called early, so don't rely on | |
286 | * our static variables being initialised. | |
287 | */ | |
288 | switch (type) { | |
289 | case TYPE_INST: | |
290 | return get_num_brps(); | |
291 | case TYPE_DATA: | |
292 | return get_num_wrps(); | |
293 | default: | |
294 | pr_warning("unknown slot type: %d\n", type); | |
295 | return 0; | |
296 | } | |
297 | } | |
298 | ||
f81ef4a9 WD |
299 | /* |
300 | * Check if 8-bit byte-address select is available. | |
301 | * This clobbers WRP 0. | |
302 | */ | |
303 | static u8 get_max_wp_len(void) | |
304 | { | |
305 | u32 ctrl_reg; | |
306 | struct arch_hw_breakpoint_ctrl ctrl; | |
307 | u8 size = 4; | |
308 | ||
309 | if (debug_arch < ARM_DEBUG_ARCH_V7_ECP14) | |
310 | goto out; | |
311 | ||
f81ef4a9 WD |
312 | memset(&ctrl, 0, sizeof(ctrl)); |
313 | ctrl.len = ARM_BREAKPOINT_LEN_8; | |
314 | ctrl_reg = encode_ctrl_reg(ctrl); | |
315 | ||
316 | write_wb_reg(ARM_BASE_WVR, 0); | |
317 | write_wb_reg(ARM_BASE_WCR, ctrl_reg); | |
318 | if ((read_wb_reg(ARM_BASE_WCR) & ctrl_reg) == ctrl_reg) | |
319 | size = 8; | |
320 | ||
321 | out: | |
322 | return size; | |
323 | } | |
324 | ||
325 | u8 arch_get_max_wp_len(void) | |
326 | { | |
327 | return max_watchpoint_len; | |
328 | } | |
329 | ||
f81ef4a9 WD |
330 | /* |
331 | * Install a perf counter breakpoint. | |
332 | */ | |
333 | int arch_install_hw_breakpoint(struct perf_event *bp) | |
334 | { | |
335 | struct arch_hw_breakpoint *info = counter_arch_bp(bp); | |
336 | struct perf_event **slot, **slots; | |
0daa034e | 337 | int i, max_slots, ctrl_base, val_base; |
93a04a34 | 338 | u32 addr, ctrl; |
f81ef4a9 | 339 | |
93a04a34 WD |
340 | addr = info->address; |
341 | ctrl = encode_ctrl_reg(info->ctrl) | 0x1; | |
342 | ||
f81ef4a9 WD |
343 | if (info->ctrl.type == ARM_BREAKPOINT_EXECUTE) { |
344 | /* Breakpoint */ | |
345 | ctrl_base = ARM_BASE_BCR; | |
346 | val_base = ARM_BASE_BVR; | |
4a55c18e | 347 | slots = (struct perf_event **)__get_cpu_var(bp_on_reg); |
0017ff42 | 348 | max_slots = core_num_brps; |
f81ef4a9 WD |
349 | } else { |
350 | /* Watchpoint */ | |
6f26aa05 WD |
351 | ctrl_base = ARM_BASE_WCR; |
352 | val_base = ARM_BASE_WVR; | |
4a55c18e | 353 | slots = (struct perf_event **)__get_cpu_var(wp_on_reg); |
f81ef4a9 WD |
354 | max_slots = core_num_wrps; |
355 | } | |
356 | ||
357 | for (i = 0; i < max_slots; ++i) { | |
358 | slot = &slots[i]; | |
359 | ||
360 | if (!*slot) { | |
361 | *slot = bp; | |
362 | break; | |
363 | } | |
364 | } | |
365 | ||
f435ab79 WD |
366 | if (i == max_slots) { |
367 | pr_warning("Can't find any breakpoint slot\n"); | |
0daa034e | 368 | return -EBUSY; |
f435ab79 | 369 | } |
f81ef4a9 | 370 | |
6f26aa05 WD |
371 | /* Override the breakpoint data with the step data. */ |
372 | if (info->step_ctrl.enabled) { | |
373 | addr = info->trigger & ~0x3; | |
374 | ctrl = encode_ctrl_reg(info->step_ctrl); | |
375 | if (info->ctrl.type != ARM_BREAKPOINT_EXECUTE) { | |
376 | i = 0; | |
377 | ctrl_base = ARM_BASE_BCR + core_num_brps; | |
378 | val_base = ARM_BASE_BVR + core_num_brps; | |
379 | } | |
380 | } | |
381 | ||
f81ef4a9 | 382 | /* Setup the address register. */ |
93a04a34 | 383 | write_wb_reg(val_base + i, addr); |
f81ef4a9 WD |
384 | |
385 | /* Setup the control register. */ | |
93a04a34 | 386 | write_wb_reg(ctrl_base + i, ctrl); |
0daa034e | 387 | return 0; |
f81ef4a9 WD |
388 | } |
389 | ||
390 | void arch_uninstall_hw_breakpoint(struct perf_event *bp) | |
391 | { | |
392 | struct arch_hw_breakpoint *info = counter_arch_bp(bp); | |
393 | struct perf_event **slot, **slots; | |
394 | int i, max_slots, base; | |
395 | ||
396 | if (info->ctrl.type == ARM_BREAKPOINT_EXECUTE) { | |
397 | /* Breakpoint */ | |
398 | base = ARM_BASE_BCR; | |
4a55c18e | 399 | slots = (struct perf_event **)__get_cpu_var(bp_on_reg); |
0017ff42 | 400 | max_slots = core_num_brps; |
f81ef4a9 WD |
401 | } else { |
402 | /* Watchpoint */ | |
6f26aa05 | 403 | base = ARM_BASE_WCR; |
4a55c18e | 404 | slots = (struct perf_event **)__get_cpu_var(wp_on_reg); |
f81ef4a9 WD |
405 | max_slots = core_num_wrps; |
406 | } | |
407 | ||
408 | /* Remove the breakpoint. */ | |
409 | for (i = 0; i < max_slots; ++i) { | |
410 | slot = &slots[i]; | |
411 | ||
412 | if (*slot == bp) { | |
413 | *slot = NULL; | |
414 | break; | |
415 | } | |
416 | } | |
417 | ||
f435ab79 WD |
418 | if (i == max_slots) { |
419 | pr_warning("Can't find any breakpoint slot\n"); | |
f81ef4a9 | 420 | return; |
f435ab79 | 421 | } |
f81ef4a9 | 422 | |
6f26aa05 WD |
423 | /* Ensure that we disable the mismatch breakpoint. */ |
424 | if (info->ctrl.type != ARM_BREAKPOINT_EXECUTE && | |
425 | info->step_ctrl.enabled) { | |
426 | i = 0; | |
427 | base = ARM_BASE_BCR + core_num_brps; | |
428 | } | |
429 | ||
f81ef4a9 WD |
430 | /* Reset the control register. */ |
431 | write_wb_reg(base + i, 0); | |
432 | } | |
433 | ||
434 | static int get_hbp_len(u8 hbp_len) | |
435 | { | |
436 | unsigned int len_in_bytes = 0; | |
437 | ||
438 | switch (hbp_len) { | |
439 | case ARM_BREAKPOINT_LEN_1: | |
440 | len_in_bytes = 1; | |
441 | break; | |
442 | case ARM_BREAKPOINT_LEN_2: | |
443 | len_in_bytes = 2; | |
444 | break; | |
445 | case ARM_BREAKPOINT_LEN_4: | |
446 | len_in_bytes = 4; | |
447 | break; | |
448 | case ARM_BREAKPOINT_LEN_8: | |
449 | len_in_bytes = 8; | |
450 | break; | |
451 | } | |
452 | ||
453 | return len_in_bytes; | |
454 | } | |
455 | ||
456 | /* | |
457 | * Check whether bp virtual address is in kernel space. | |
458 | */ | |
459 | int arch_check_bp_in_kernelspace(struct perf_event *bp) | |
460 | { | |
461 | unsigned int len; | |
462 | unsigned long va; | |
463 | struct arch_hw_breakpoint *info = counter_arch_bp(bp); | |
464 | ||
465 | va = info->address; | |
466 | len = get_hbp_len(info->ctrl.len); | |
467 | ||
468 | return (va >= TASK_SIZE) && ((va + len - 1) >= TASK_SIZE); | |
469 | } | |
470 | ||
471 | /* | |
472 | * Extract generic type and length encodings from an arch_hw_breakpoint_ctrl. | |
473 | * Hopefully this will disappear when ptrace can bypass the conversion | |
474 | * to generic breakpoint descriptions. | |
475 | */ | |
476 | int arch_bp_generic_fields(struct arch_hw_breakpoint_ctrl ctrl, | |
477 | int *gen_len, int *gen_type) | |
478 | { | |
479 | /* Type */ | |
480 | switch (ctrl.type) { | |
481 | case ARM_BREAKPOINT_EXECUTE: | |
482 | *gen_type = HW_BREAKPOINT_X; | |
483 | break; | |
484 | case ARM_BREAKPOINT_LOAD: | |
485 | *gen_type = HW_BREAKPOINT_R; | |
486 | break; | |
487 | case ARM_BREAKPOINT_STORE: | |
488 | *gen_type = HW_BREAKPOINT_W; | |
489 | break; | |
490 | case ARM_BREAKPOINT_LOAD | ARM_BREAKPOINT_STORE: | |
491 | *gen_type = HW_BREAKPOINT_RW; | |
492 | break; | |
493 | default: | |
494 | return -EINVAL; | |
495 | } | |
496 | ||
497 | /* Len */ | |
498 | switch (ctrl.len) { | |
499 | case ARM_BREAKPOINT_LEN_1: | |
500 | *gen_len = HW_BREAKPOINT_LEN_1; | |
501 | break; | |
502 | case ARM_BREAKPOINT_LEN_2: | |
503 | *gen_len = HW_BREAKPOINT_LEN_2; | |
504 | break; | |
505 | case ARM_BREAKPOINT_LEN_4: | |
506 | *gen_len = HW_BREAKPOINT_LEN_4; | |
507 | break; | |
508 | case ARM_BREAKPOINT_LEN_8: | |
509 | *gen_len = HW_BREAKPOINT_LEN_8; | |
510 | break; | |
511 | default: | |
512 | return -EINVAL; | |
513 | } | |
514 | ||
515 | return 0; | |
516 | } | |
517 | ||
518 | /* | |
519 | * Construct an arch_hw_breakpoint from a perf_event. | |
520 | */ | |
521 | static int arch_build_bp_info(struct perf_event *bp) | |
522 | { | |
523 | struct arch_hw_breakpoint *info = counter_arch_bp(bp); | |
524 | ||
525 | /* Type */ | |
526 | switch (bp->attr.bp_type) { | |
527 | case HW_BREAKPOINT_X: | |
528 | info->ctrl.type = ARM_BREAKPOINT_EXECUTE; | |
529 | break; | |
530 | case HW_BREAKPOINT_R: | |
531 | info->ctrl.type = ARM_BREAKPOINT_LOAD; | |
532 | break; | |
533 | case HW_BREAKPOINT_W: | |
534 | info->ctrl.type = ARM_BREAKPOINT_STORE; | |
535 | break; | |
536 | case HW_BREAKPOINT_RW: | |
537 | info->ctrl.type = ARM_BREAKPOINT_LOAD | ARM_BREAKPOINT_STORE; | |
538 | break; | |
539 | default: | |
540 | return -EINVAL; | |
541 | } | |
542 | ||
543 | /* Len */ | |
544 | switch (bp->attr.bp_len) { | |
545 | case HW_BREAKPOINT_LEN_1: | |
546 | info->ctrl.len = ARM_BREAKPOINT_LEN_1; | |
547 | break; | |
548 | case HW_BREAKPOINT_LEN_2: | |
549 | info->ctrl.len = ARM_BREAKPOINT_LEN_2; | |
550 | break; | |
551 | case HW_BREAKPOINT_LEN_4: | |
552 | info->ctrl.len = ARM_BREAKPOINT_LEN_4; | |
553 | break; | |
554 | case HW_BREAKPOINT_LEN_8: | |
555 | info->ctrl.len = ARM_BREAKPOINT_LEN_8; | |
556 | if ((info->ctrl.type != ARM_BREAKPOINT_EXECUTE) | |
557 | && max_watchpoint_len >= 8) | |
558 | break; | |
559 | default: | |
560 | return -EINVAL; | |
561 | } | |
562 | ||
6ee33c27 WD |
563 | /* |
564 | * Breakpoints must be of length 2 (thumb) or 4 (ARM) bytes. | |
565 | * Watchpoints can be of length 1, 2, 4 or 8 bytes if supported | |
566 | * by the hardware and must be aligned to the appropriate number of | |
567 | * bytes. | |
568 | */ | |
569 | if (info->ctrl.type == ARM_BREAKPOINT_EXECUTE && | |
570 | info->ctrl.len != ARM_BREAKPOINT_LEN_2 && | |
571 | info->ctrl.len != ARM_BREAKPOINT_LEN_4) | |
572 | return -EINVAL; | |
573 | ||
f81ef4a9 WD |
574 | /* Address */ |
575 | info->address = bp->attr.bp_addr; | |
576 | ||
577 | /* Privilege */ | |
578 | info->ctrl.privilege = ARM_BREAKPOINT_USER; | |
93a04a34 | 579 | if (arch_check_bp_in_kernelspace(bp)) |
f81ef4a9 WD |
580 | info->ctrl.privilege |= ARM_BREAKPOINT_PRIV; |
581 | ||
582 | /* Enabled? */ | |
583 | info->ctrl.enabled = !bp->attr.disabled; | |
584 | ||
585 | /* Mismatch */ | |
586 | info->ctrl.mismatch = 0; | |
587 | ||
588 | return 0; | |
589 | } | |
590 | ||
591 | /* | |
592 | * Validate the arch-specific HW Breakpoint register settings. | |
593 | */ | |
594 | int arch_validate_hwbkpt_settings(struct perf_event *bp) | |
595 | { | |
596 | struct arch_hw_breakpoint *info = counter_arch_bp(bp); | |
597 | int ret = 0; | |
6ee33c27 | 598 | u32 offset, alignment_mask = 0x3; |
f81ef4a9 | 599 | |
0daa034e WD |
600 | /* Ensure that we are in monitor debug mode. */ |
601 | if (!monitor_mode_enabled()) | |
602 | return -ENODEV; | |
603 | ||
f81ef4a9 WD |
604 | /* Build the arch_hw_breakpoint. */ |
605 | ret = arch_build_bp_info(bp); | |
606 | if (ret) | |
607 | goto out; | |
608 | ||
609 | /* Check address alignment. */ | |
610 | if (info->ctrl.len == ARM_BREAKPOINT_LEN_8) | |
611 | alignment_mask = 0x7; | |
6ee33c27 WD |
612 | offset = info->address & alignment_mask; |
613 | switch (offset) { | |
614 | case 0: | |
615 | /* Aligned */ | |
616 | break; | |
617 | case 1: | |
6ee33c27 WD |
618 | case 2: |
619 | /* Allow halfword watchpoints and breakpoints. */ | |
620 | if (info->ctrl.len == ARM_BREAKPOINT_LEN_2) | |
621 | break; | |
d968d2b8 WD |
622 | case 3: |
623 | /* Allow single byte watchpoint. */ | |
624 | if (info->ctrl.len == ARM_BREAKPOINT_LEN_1) | |
625 | break; | |
6ee33c27 WD |
626 | default: |
627 | ret = -EINVAL; | |
628 | goto out; | |
f81ef4a9 WD |
629 | } |
630 | ||
6ee33c27 WD |
631 | info->address &= ~alignment_mask; |
632 | info->ctrl.len <<= offset; | |
633 | ||
bf880114 WD |
634 | if (!bp->overflow_handler) { |
635 | /* | |
636 | * Mismatch breakpoints are required for single-stepping | |
637 | * breakpoints. | |
638 | */ | |
639 | if (!core_has_mismatch_brps()) | |
640 | return -EINVAL; | |
641 | ||
642 | /* We don't allow mismatch breakpoints in kernel space. */ | |
643 | if (arch_check_bp_in_kernelspace(bp)) | |
644 | return -EPERM; | |
645 | ||
646 | /* | |
647 | * Per-cpu breakpoints are not supported by our stepping | |
648 | * mechanism. | |
649 | */ | |
650 | if (!bp->hw.bp_target) | |
651 | return -EINVAL; | |
652 | ||
653 | /* | |
654 | * We only support specific access types if the fsr | |
655 | * reports them. | |
656 | */ | |
657 | if (!debug_exception_updates_fsr() && | |
658 | (info->ctrl.type == ARM_BREAKPOINT_LOAD || | |
659 | info->ctrl.type == ARM_BREAKPOINT_STORE)) | |
660 | return -EINVAL; | |
f81ef4a9 | 661 | } |
bf880114 | 662 | |
f81ef4a9 WD |
663 | out: |
664 | return ret; | |
665 | } | |
666 | ||
9ebb3cbc WD |
667 | /* |
668 | * Enable/disable single-stepping over the breakpoint bp at address addr. | |
669 | */ | |
670 | static void enable_single_step(struct perf_event *bp, u32 addr) | |
f81ef4a9 | 671 | { |
9ebb3cbc | 672 | struct arch_hw_breakpoint *info = counter_arch_bp(bp); |
f81ef4a9 | 673 | |
9ebb3cbc WD |
674 | arch_uninstall_hw_breakpoint(bp); |
675 | info->step_ctrl.mismatch = 1; | |
676 | info->step_ctrl.len = ARM_BREAKPOINT_LEN_4; | |
677 | info->step_ctrl.type = ARM_BREAKPOINT_EXECUTE; | |
678 | info->step_ctrl.privilege = info->ctrl.privilege; | |
679 | info->step_ctrl.enabled = 1; | |
680 | info->trigger = addr; | |
681 | arch_install_hw_breakpoint(bp); | |
682 | } | |
f81ef4a9 | 683 | |
9ebb3cbc WD |
684 | static void disable_single_step(struct perf_event *bp) |
685 | { | |
686 | arch_uninstall_hw_breakpoint(bp); | |
687 | counter_arch_bp(bp)->step_ctrl.enabled = 0; | |
688 | arch_install_hw_breakpoint(bp); | |
f81ef4a9 WD |
689 | } |
690 | ||
6f26aa05 WD |
691 | static void watchpoint_handler(unsigned long addr, unsigned int fsr, |
692 | struct pt_regs *regs) | |
f81ef4a9 | 693 | { |
6f26aa05 WD |
694 | int i, access; |
695 | u32 val, ctrl_reg, alignment_mask; | |
4a55c18e | 696 | struct perf_event *wp, **slots; |
f81ef4a9 | 697 | struct arch_hw_breakpoint *info; |
6f26aa05 | 698 | struct arch_hw_breakpoint_ctrl ctrl; |
f81ef4a9 | 699 | |
4a55c18e WD |
700 | slots = (struct perf_event **)__get_cpu_var(wp_on_reg); |
701 | ||
f81ef4a9 WD |
702 | for (i = 0; i < core_num_wrps; ++i) { |
703 | rcu_read_lock(); | |
704 | ||
93a04a34 WD |
705 | wp = slots[i]; |
706 | ||
6f26aa05 WD |
707 | if (wp == NULL) |
708 | goto unlock; | |
f81ef4a9 | 709 | |
6f26aa05 | 710 | info = counter_arch_bp(wp); |
f81ef4a9 | 711 | /* |
6f26aa05 WD |
712 | * The DFAR is an unknown value on debug architectures prior |
713 | * to 7.1. Since we only allow a single watchpoint on these | |
714 | * older CPUs, we can set the trigger to the lowest possible | |
715 | * faulting address. | |
f81ef4a9 | 716 | */ |
6f26aa05 WD |
717 | if (debug_arch < ARM_DEBUG_ARCH_V7_1) { |
718 | BUG_ON(i > 0); | |
719 | info->trigger = wp->attr.bp_addr; | |
720 | } else { | |
721 | if (info->ctrl.len == ARM_BREAKPOINT_LEN_8) | |
722 | alignment_mask = 0x7; | |
723 | else | |
724 | alignment_mask = 0x3; | |
725 | ||
726 | /* Check if the watchpoint value matches. */ | |
727 | val = read_wb_reg(ARM_BASE_WVR + i); | |
728 | if (val != (addr & ~alignment_mask)) | |
729 | goto unlock; | |
730 | ||
731 | /* Possible match, check the byte address select. */ | |
732 | ctrl_reg = read_wb_reg(ARM_BASE_WCR + i); | |
733 | decode_ctrl_reg(ctrl_reg, &ctrl); | |
734 | if (!((1 << (addr & alignment_mask)) & ctrl.len)) | |
735 | goto unlock; | |
736 | ||
737 | /* Check that the access type matches. */ | |
bf880114 WD |
738 | if (debug_exception_updates_fsr()) { |
739 | access = (fsr & ARM_FSR_ACCESS_MASK) ? | |
740 | HW_BREAKPOINT_W : HW_BREAKPOINT_R; | |
741 | if (!(access & hw_breakpoint_type(wp))) | |
742 | goto unlock; | |
743 | } | |
6f26aa05 WD |
744 | |
745 | /* We have a winner. */ | |
746 | info->trigger = addr; | |
747 | } | |
748 | ||
f81ef4a9 | 749 | pr_debug("watchpoint fired: address = 0x%x\n", info->trigger); |
93a04a34 | 750 | perf_bp_event(wp, regs); |
f81ef4a9 WD |
751 | |
752 | /* | |
753 | * If no overflow handler is present, insert a temporary | |
754 | * mismatch breakpoint so we can single-step over the | |
755 | * watchpoint trigger. | |
756 | */ | |
9ebb3cbc WD |
757 | if (!wp->overflow_handler) |
758 | enable_single_step(wp, instruction_pointer(regs)); | |
f81ef4a9 | 759 | |
6f26aa05 | 760 | unlock: |
f81ef4a9 WD |
761 | rcu_read_unlock(); |
762 | } | |
763 | } | |
764 | ||
93a04a34 WD |
765 | static void watchpoint_single_step_handler(unsigned long pc) |
766 | { | |
767 | int i; | |
4a55c18e | 768 | struct perf_event *wp, **slots; |
93a04a34 WD |
769 | struct arch_hw_breakpoint *info; |
770 | ||
4a55c18e WD |
771 | slots = (struct perf_event **)__get_cpu_var(wp_on_reg); |
772 | ||
c512de95 | 773 | for (i = 0; i < core_num_wrps; ++i) { |
93a04a34 WD |
774 | rcu_read_lock(); |
775 | ||
776 | wp = slots[i]; | |
777 | ||
778 | if (wp == NULL) | |
779 | goto unlock; | |
780 | ||
781 | info = counter_arch_bp(wp); | |
782 | if (!info->step_ctrl.enabled) | |
783 | goto unlock; | |
784 | ||
785 | /* | |
786 | * Restore the original watchpoint if we've completed the | |
787 | * single-step. | |
788 | */ | |
9ebb3cbc WD |
789 | if (info->trigger != pc) |
790 | disable_single_step(wp); | |
93a04a34 WD |
791 | |
792 | unlock: | |
793 | rcu_read_unlock(); | |
794 | } | |
795 | } | |
796 | ||
f81ef4a9 WD |
797 | static void breakpoint_handler(unsigned long unknown, struct pt_regs *regs) |
798 | { | |
799 | int i; | |
f81ef4a9 | 800 | u32 ctrl_reg, val, addr; |
4a55c18e | 801 | struct perf_event *bp, **slots; |
f81ef4a9 WD |
802 | struct arch_hw_breakpoint *info; |
803 | struct arch_hw_breakpoint_ctrl ctrl; | |
804 | ||
4a55c18e WD |
805 | slots = (struct perf_event **)__get_cpu_var(bp_on_reg); |
806 | ||
f81ef4a9 WD |
807 | /* The exception entry code places the amended lr in the PC. */ |
808 | addr = regs->ARM_pc; | |
809 | ||
93a04a34 WD |
810 | /* Check the currently installed breakpoints first. */ |
811 | for (i = 0; i < core_num_brps; ++i) { | |
f81ef4a9 WD |
812 | rcu_read_lock(); |
813 | ||
814 | bp = slots[i]; | |
815 | ||
9ebb3cbc WD |
816 | if (bp == NULL) |
817 | goto unlock; | |
f81ef4a9 | 818 | |
9ebb3cbc | 819 | info = counter_arch_bp(bp); |
f81ef4a9 WD |
820 | |
821 | /* Check if the breakpoint value matches. */ | |
822 | val = read_wb_reg(ARM_BASE_BVR + i); | |
823 | if (val != (addr & ~0x3)) | |
9ebb3cbc | 824 | goto mismatch; |
f81ef4a9 WD |
825 | |
826 | /* Possible match, check the byte address select to confirm. */ | |
827 | ctrl_reg = read_wb_reg(ARM_BASE_BCR + i); | |
828 | decode_ctrl_reg(ctrl_reg, &ctrl); | |
829 | if ((1 << (addr & 0x3)) & ctrl.len) { | |
f81ef4a9 | 830 | info->trigger = addr; |
f81ef4a9 WD |
831 | pr_debug("breakpoint fired: address = 0x%x\n", addr); |
832 | perf_bp_event(bp, regs); | |
9ebb3cbc WD |
833 | if (!bp->overflow_handler) |
834 | enable_single_step(bp, addr); | |
835 | goto unlock; | |
f81ef4a9 WD |
836 | } |
837 | ||
9ebb3cbc WD |
838 | mismatch: |
839 | /* If we're stepping a breakpoint, it can now be restored. */ | |
840 | if (info->step_ctrl.enabled) | |
841 | disable_single_step(bp); | |
842 | unlock: | |
f81ef4a9 WD |
843 | rcu_read_unlock(); |
844 | } | |
93a04a34 WD |
845 | |
846 | /* Handle any pending watchpoint single-step breakpoints. */ | |
847 | watchpoint_single_step_handler(addr); | |
f81ef4a9 WD |
848 | } |
849 | ||
850 | /* | |
851 | * Called from either the Data Abort Handler [watchpoint] or the | |
02fe2845 | 852 | * Prefetch Abort Handler [breakpoint] with interrupts disabled. |
f81ef4a9 WD |
853 | */ |
854 | static int hw_breakpoint_pending(unsigned long addr, unsigned int fsr, | |
855 | struct pt_regs *regs) | |
856 | { | |
7e202696 | 857 | int ret = 0; |
f81ef4a9 WD |
858 | u32 dscr; |
859 | ||
02fe2845 RK |
860 | preempt_disable(); |
861 | ||
862 | if (interrupts_enabled(regs)) | |
863 | local_irq_enable(); | |
7e202696 | 864 | |
f81ef4a9 | 865 | /* We only handle watchpoints and hardware breakpoints. */ |
9e962f76 | 866 | ARM_DBG_READ(c0, c1, 0, dscr); |
f81ef4a9 WD |
867 | |
868 | /* Perform perf callbacks. */ | |
869 | switch (ARM_DSCR_MOE(dscr)) { | |
870 | case ARM_ENTRY_BREAKPOINT: | |
871 | breakpoint_handler(addr, regs); | |
872 | break; | |
873 | case ARM_ENTRY_ASYNC_WATCHPOINT: | |
235584b6 | 874 | WARN(1, "Asynchronous watchpoint exception taken. Debugging results may be unreliable\n"); |
f81ef4a9 | 875 | case ARM_ENTRY_SYNC_WATCHPOINT: |
6f26aa05 | 876 | watchpoint_handler(addr, fsr, regs); |
f81ef4a9 WD |
877 | break; |
878 | default: | |
7e202696 | 879 | ret = 1; /* Unhandled fault. */ |
f81ef4a9 WD |
880 | } |
881 | ||
7e202696 WD |
882 | preempt_enable(); |
883 | ||
f81ef4a9 WD |
884 | return ret; |
885 | } | |
886 | ||
887 | /* | |
888 | * One-time initialisation. | |
889 | */ | |
0d352e3d WD |
890 | static cpumask_t debug_err_mask; |
891 | ||
892 | static int debug_reg_trap(struct pt_regs *regs, unsigned int instr) | |
893 | { | |
894 | int cpu = smp_processor_id(); | |
895 | ||
896 | pr_warning("Debug register access (0x%x) caused undefined instruction on CPU %d\n", | |
897 | instr, cpu); | |
898 | ||
899 | /* Set the error flag for this CPU and skip the faulting instruction. */ | |
900 | cpumask_set_cpu(cpu, &debug_err_mask); | |
901 | instruction_pointer(regs) += 4; | |
902 | return 0; | |
903 | } | |
904 | ||
905 | static struct undef_hook debug_reg_hook = { | |
906 | .instr_mask = 0x0fe80f10, | |
907 | .instr_val = 0x0e000e10, | |
908 | .fn = debug_reg_trap, | |
909 | }; | |
910 | ||
57ba8997 DE |
911 | /* Does this core support OS Save and Restore? */ |
912 | static bool core_has_os_save_restore(void) | |
913 | { | |
914 | u32 oslsr; | |
915 | ||
916 | switch (get_debug_arch()) { | |
917 | case ARM_DEBUG_ARCH_V7_1: | |
918 | return true; | |
919 | case ARM_DEBUG_ARCH_V7_ECP14: | |
920 | ARM_DBG_READ(c1, c1, 4, oslsr); | |
921 | if (oslsr & ARM_OSLSR_OSLM0) | |
922 | return true; | |
923 | default: | |
924 | return false; | |
925 | } | |
926 | } | |
927 | ||
0d352e3d | 928 | static void reset_ctrl_regs(void *unused) |
f81ef4a9 | 929 | { |
c512de95 | 930 | int i, raw_num_brps, err = 0, cpu = smp_processor_id(); |
e64877dc | 931 | u32 val; |
f81ef4a9 | 932 | |
ac88e071 WD |
933 | /* |
934 | * v7 debug contains save and restore registers so that debug state | |
ed19b739 WD |
935 | * can be maintained across low-power modes without leaving the debug |
936 | * logic powered up. It is IMPLEMENTATION DEFINED whether we can access | |
937 | * the debug registers out of reset, so we must unlock the OS Lock | |
938 | * Access Register to avoid taking undefined instruction exceptions | |
939 | * later on. | |
ac88e071 | 940 | */ |
b5d5b8f9 | 941 | switch (debug_arch) { |
a26bce12 WD |
942 | case ARM_DEBUG_ARCH_V6: |
943 | case ARM_DEBUG_ARCH_V6_1: | |
7f4050a0 WD |
944 | /* ARMv6 cores clear the registers out of reset. */ |
945 | goto out_mdbgen; | |
b5d5b8f9 | 946 | case ARM_DEBUG_ARCH_V7_ECP14: |
c09bae70 WD |
947 | /* |
948 | * Ensure sticky power-down is clear (i.e. debug logic is | |
949 | * powered up). | |
950 | */ | |
9e962f76 | 951 | ARM_DBG_READ(c1, c5, 4, val); |
e64877dc | 952 | if ((val & 0x1) == 0) |
b5d5b8f9 | 953 | err = -EPERM; |
e64877dc | 954 | |
57ba8997 | 955 | if (!has_ossr) |
e64877dc | 956 | goto clear_vcr; |
b5d5b8f9 WD |
957 | break; |
958 | case ARM_DEBUG_ARCH_V7_1: | |
ac88e071 | 959 | /* |
b5d5b8f9 | 960 | * Ensure the OS double lock is clear. |
ac88e071 | 961 | */ |
9e962f76 | 962 | ARM_DBG_READ(c1, c3, 4, val); |
e64877dc | 963 | if ((val & 0x1) == 1) |
b5d5b8f9 WD |
964 | err = -EPERM; |
965 | break; | |
966 | } | |
e89c0d70 | 967 | |
b5d5b8f9 | 968 | if (err) { |
68a154fc | 969 | pr_warn_once("CPU %d debug is powered down!\n", cpu); |
0d352e3d | 970 | cpumask_or(&debug_err_mask, &debug_err_mask, cpumask_of(cpu)); |
b5d5b8f9 | 971 | return; |
ac88e071 WD |
972 | } |
973 | ||
b5d5b8f9 | 974 | /* |
e64877dc | 975 | * Unconditionally clear the OS lock by writing a value |
02051ead | 976 | * other than CS_LAR_KEY to the access register. |
b5d5b8f9 | 977 | */ |
02051ead | 978 | ARM_DBG_WRITE(c1, c0, 4, ~CS_LAR_KEY); |
b5d5b8f9 WD |
979 | isb(); |
980 | ||
981 | /* | |
982 | * Clear any configured vector-catch events before | |
983 | * enabling monitor mode. | |
984 | */ | |
e64877dc | 985 | clear_vcr: |
9e962f76 | 986 | ARM_DBG_WRITE(c0, c7, 0, 0); |
b5d5b8f9 WD |
987 | isb(); |
988 | ||
614bea50 | 989 | if (cpumask_intersects(&debug_err_mask, cpumask_of(cpu))) { |
68a154fc | 990 | pr_warn_once("CPU %d failed to disable vector catch\n", cpu); |
f81ef4a9 | 991 | return; |
614bea50 | 992 | } |
f81ef4a9 | 993 | |
614bea50 WD |
994 | /* |
995 | * The control/value register pairs are UNKNOWN out of reset so | |
996 | * clear them to avoid spurious debug events. | |
997 | */ | |
c512de95 WD |
998 | raw_num_brps = get_num_brp_resources(); |
999 | for (i = 0; i < raw_num_brps; ++i) { | |
f81ef4a9 WD |
1000 | write_wb_reg(ARM_BASE_BCR + i, 0UL); |
1001 | write_wb_reg(ARM_BASE_BVR + i, 0UL); | |
1002 | } | |
1003 | ||
1004 | for (i = 0; i < core_num_wrps; ++i) { | |
1005 | write_wb_reg(ARM_BASE_WCR + i, 0UL); | |
1006 | write_wb_reg(ARM_BASE_WVR + i, 0UL); | |
1007 | } | |
614bea50 WD |
1008 | |
1009 | if (cpumask_intersects(&debug_err_mask, cpumask_of(cpu))) { | |
68a154fc | 1010 | pr_warn_once("CPU %d failed to clear debug register pairs\n", cpu); |
614bea50 WD |
1011 | return; |
1012 | } | |
1013 | ||
1014 | /* | |
1015 | * Have a crack at enabling monitor mode. We don't actually need | |
1016 | * it yet, but reporting an error early is useful if it fails. | |
1017 | */ | |
7f4050a0 | 1018 | out_mdbgen: |
614bea50 WD |
1019 | if (enable_monitor_mode()) |
1020 | cpumask_or(&debug_err_mask, &debug_err_mask, cpumask_of(cpu)); | |
f81ef4a9 WD |
1021 | } |
1022 | ||
8bd26e3a | 1023 | static int dbg_reset_notify(struct notifier_block *self, |
7d99331e WD |
1024 | unsigned long action, void *cpu) |
1025 | { | |
1a8e6118 | 1026 | if ((action & ~CPU_TASKS_FROZEN) == CPU_ONLINE) |
7d99331e | 1027 | smp_call_function_single((int)cpu, reset_ctrl_regs, NULL, 1); |
0d352e3d | 1028 | |
7d99331e WD |
1029 | return NOTIFY_OK; |
1030 | } | |
1031 | ||
8bd26e3a | 1032 | static struct notifier_block dbg_reset_nb = { |
7d99331e WD |
1033 | .notifier_call = dbg_reset_notify, |
1034 | }; | |
1035 | ||
9a6eb310 DE |
1036 | #ifdef CONFIG_CPU_PM |
1037 | static int dbg_cpu_pm_notify(struct notifier_block *self, unsigned long action, | |
1038 | void *v) | |
1039 | { | |
1040 | if (action == CPU_PM_EXIT) | |
1041 | reset_ctrl_regs(NULL); | |
1042 | ||
1043 | return NOTIFY_OK; | |
1044 | } | |
1045 | ||
50acff3c | 1046 | static struct notifier_block dbg_cpu_pm_nb = { |
9a6eb310 DE |
1047 | .notifier_call = dbg_cpu_pm_notify, |
1048 | }; | |
1049 | ||
1050 | static void __init pm_init(void) | |
1051 | { | |
1052 | cpu_pm_register_notifier(&dbg_cpu_pm_nb); | |
1053 | } | |
1054 | #else | |
1055 | static inline void pm_init(void) | |
1056 | { | |
1057 | } | |
1058 | #endif | |
1059 | ||
f81ef4a9 WD |
1060 | static int __init arch_hw_breakpoint_init(void) |
1061 | { | |
f81ef4a9 WD |
1062 | debug_arch = get_debug_arch(); |
1063 | ||
66e1cfe6 | 1064 | if (!debug_arch_supported()) { |
f81ef4a9 | 1065 | pr_info("debug architecture 0x%x unsupported.\n", debug_arch); |
8fbf397c | 1066 | return 0; |
f81ef4a9 WD |
1067 | } |
1068 | ||
57ba8997 DE |
1069 | has_ossr = core_has_os_save_restore(); |
1070 | ||
f81ef4a9 WD |
1071 | /* Determine how many BRPs/WRPs are available. */ |
1072 | core_num_brps = get_num_brps(); | |
1073 | core_num_wrps = get_num_wrps(); | |
1074 | ||
0d352e3d WD |
1075 | /* |
1076 | * We need to tread carefully here because DBGSWENABLE may be | |
1077 | * driven low on this core and there isn't an architected way to | |
1078 | * determine that. | |
1079 | */ | |
1080 | register_undef_hook(&debug_reg_hook); | |
f81ef4a9 | 1081 | |
ed19b739 WD |
1082 | /* |
1083 | * Reset the breakpoint resources. We assume that a halting | |
1084 | * debugger will leave the world in a nice state for us. | |
1085 | */ | |
0d352e3d WD |
1086 | on_each_cpu(reset_ctrl_regs, NULL, 1); |
1087 | unregister_undef_hook(&debug_reg_hook); | |
1088 | if (!cpumask_empty(&debug_err_mask)) { | |
c09bae70 | 1089 | core_num_brps = 0; |
c09bae70 WD |
1090 | core_num_wrps = 0; |
1091 | return 0; | |
1092 | } | |
ed19b739 | 1093 | |
0d352e3d WD |
1094 | pr_info("found %d " "%s" "breakpoint and %d watchpoint registers.\n", |
1095 | core_num_brps, core_has_mismatch_brps() ? "(+1 reserved) " : | |
1096 | "", core_num_wrps); | |
1097 | ||
b59a540c WD |
1098 | /* Work out the maximum supported watchpoint length. */ |
1099 | max_watchpoint_len = get_max_wp_len(); | |
1100 | pr_info("maximum watchpoint size is %u bytes.\n", | |
1101 | max_watchpoint_len); | |
f81ef4a9 WD |
1102 | |
1103 | /* Register debug fault handler. */ | |
f7b8156d CM |
1104 | hook_fault_code(FAULT_CODE_DEBUG, hw_breakpoint_pending, SIGTRAP, |
1105 | TRAP_HWBKPT, "watchpoint debug exception"); | |
1106 | hook_ifault_code(FAULT_CODE_DEBUG, hw_breakpoint_pending, SIGTRAP, | |
1107 | TRAP_HWBKPT, "breakpoint debug exception"); | |
f81ef4a9 | 1108 | |
9a6eb310 | 1109 | /* Register hotplug and PM notifiers. */ |
7d99331e | 1110 | register_cpu_notifier(&dbg_reset_nb); |
9a6eb310 | 1111 | pm_init(); |
8fbf397c | 1112 | return 0; |
f81ef4a9 WD |
1113 | } |
1114 | arch_initcall(arch_hw_breakpoint_init); | |
1115 | ||
1116 | void hw_breakpoint_pmu_read(struct perf_event *bp) | |
1117 | { | |
1118 | } | |
1119 | ||
1120 | /* | |
1121 | * Dummy function to register with die_notifier. | |
1122 | */ | |
1123 | int hw_breakpoint_exceptions_notify(struct notifier_block *unused, | |
1124 | unsigned long val, void *data) | |
1125 | { | |
1126 | return NOTIFY_DONE; | |
1127 | } |