Commit | Line | Data |
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8b7d89d0 PP |
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 as published by | |
4 | * the Free Software Foundation; either version 2 of the License, or | |
5 | * (at your option) any later version. | |
6 | * | |
7 | * This program is distributed in the hope that it will be useful, | |
8 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
9 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
10 | * GNU General Public License for more details. | |
11 | * | |
12 | * You should have received a copy of the GNU General Public License | |
13 | * along with this program; if not, write to the Free Software | |
14 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
15 | * | |
16 | * Copyright (C) IBM Corporation, 2005 | |
17 | * Jeff Muizelaar, 2006, 2007 | |
18 | * Pekka Paalanen, 2008 <pq@iki.fi> | |
19 | * | |
20 | * Derived from the read-mod example from relay-examples by Tom Zanussi. | |
21 | */ | |
3a0340be | 22 | |
eba11d6d | 23 | #define pr_fmt(fmt) "mmiotrace: " fmt |
3a0340be | 24 | |
d61fc448 PP |
25 | #define DEBUG 1 |
26 | ||
8b7d89d0 | 27 | #include <linux/module.h> |
8b7d89d0 | 28 | #include <linux/debugfs.h> |
5a0e3ad6 | 29 | #include <linux/slab.h> |
f984b51e | 30 | #include <linux/uaccess.h> |
970e6fa0 | 31 | #include <linux/io.h> |
8b7d89d0 PP |
32 | #include <linux/version.h> |
33 | #include <linux/kallsyms.h> | |
34 | #include <asm/pgtable.h> | |
35 | #include <linux/mmiotrace.h> | |
36 | #include <asm/e820.h> /* for ISA_START_ADDRESS */ | |
fe1ffafa | 37 | #include <asm/atomic.h> |
f5136380 | 38 | #include <linux/percpu.h> |
7423d111 | 39 | #include <linux/cpu.h> |
8b7d89d0 | 40 | |
8b7d89d0 PP |
41 | #include "pf_in.h" |
42 | ||
8b7d89d0 PP |
43 | struct trap_reason { |
44 | unsigned long addr; | |
45 | unsigned long ip; | |
46 | enum reason_type type; | |
47 | int active_traces; | |
48 | }; | |
49 | ||
d61fc448 PP |
50 | struct remap_trace { |
51 | struct list_head list; | |
52 | struct kmmio_probe probe; | |
dee310d0 | 53 | resource_size_t phys; |
d61fc448 PP |
54 | unsigned long id; |
55 | }; | |
56 | ||
fe1ffafa | 57 | /* Accessed per-cpu. */ |
f5136380 | 58 | static DEFINE_PER_CPU(struct trap_reason, pf_reason); |
bd8ac686 | 59 | static DEFINE_PER_CPU(struct mmiotrace_rw, cpu_trace); |
8b7d89d0 | 60 | |
d61fc448 PP |
61 | static DEFINE_MUTEX(mmiotrace_mutex); |
62 | static DEFINE_SPINLOCK(trace_lock); | |
63 | static atomic_t mmiotrace_enabled; | |
64 | static LIST_HEAD(trace_list); /* struct remap_trace */ | |
d61fc448 PP |
65 | |
66 | /* | |
67 | * Locking in this file: | |
68 | * - mmiotrace_mutex enforces enable/disable_mmiotrace() critical sections. | |
69 | * - mmiotrace_enabled may be modified only when holding mmiotrace_mutex | |
70 | * and trace_lock. | |
71 | * - Routines depending on is_enabled() must take trace_lock. | |
72 | * - trace_list users must hold trace_lock. | |
9e57fb35 | 73 | * - is_enabled() guarantees that mmio_trace_{rw,mapping} are allowed. |
d61fc448 PP |
74 | * - pre/post callbacks assume the effect of is_enabled() being true. |
75 | */ | |
8b7d89d0 PP |
76 | |
77 | /* module parameters */ | |
d61fc448 PP |
78 | static unsigned long filter_offset; |
79 | static int nommiotrace; | |
d61fc448 | 80 | static int trace_pc; |
8b7d89d0 | 81 | |
8b7d89d0 PP |
82 | module_param(filter_offset, ulong, 0); |
83 | module_param(nommiotrace, bool, 0); | |
8b7d89d0 PP |
84 | module_param(trace_pc, bool, 0); |
85 | ||
8b7d89d0 PP |
86 | MODULE_PARM_DESC(filter_offset, "Start address of traced mappings."); |
87 | MODULE_PARM_DESC(nommiotrace, "Disable actual MMIO tracing."); | |
8b7d89d0 | 88 | MODULE_PARM_DESC(trace_pc, "Record address of faulting instructions."); |
d61fc448 PP |
89 | |
90 | static bool is_enabled(void) | |
91 | { | |
92 | return atomic_read(&mmiotrace_enabled); | |
93 | } | |
8b7d89d0 | 94 | |
8b7d89d0 PP |
95 | static void print_pte(unsigned long address) |
96 | { | |
790e2a29 | 97 | unsigned int level; |
75bb8835 PP |
98 | pte_t *pte = lookup_address(address, &level); |
99 | ||
100 | if (!pte) { | |
3a0340be JP |
101 | pr_err("Error in %s: no pte for page 0x%08lx\n", |
102 | __func__, address); | |
75bb8835 PP |
103 | return; |
104 | } | |
105 | ||
106 | if (level == PG_LEVEL_2M) { | |
3a0340be JP |
107 | pr_emerg("4MB pages are not currently supported: 0x%08lx\n", |
108 | address); | |
8b7d89d0 PP |
109 | BUG(); |
110 | } | |
3a0340be JP |
111 | pr_info("pte for 0x%lx: 0x%llx 0x%llx\n", |
112 | address, | |
0663bb6c RD |
113 | (unsigned long long)pte_val(*pte), |
114 | (unsigned long long)pte_val(*pte) & _PAGE_PRESENT); | |
8b7d89d0 PP |
115 | } |
116 | ||
117 | /* | |
118 | * For some reason the pre/post pairs have been called in an | |
119 | * unmatched order. Report and die. | |
120 | */ | |
121 | static void die_kmmio_nesting_error(struct pt_regs *regs, unsigned long addr) | |
122 | { | |
f5136380 | 123 | const struct trap_reason *my_reason = &get_cpu_var(pf_reason); |
3a0340be JP |
124 | pr_emerg("unexpected fault for address: 0x%08lx, last fault for address: 0x%08lx\n", |
125 | addr, my_reason->addr); | |
8b7d89d0 | 126 | print_pte(addr); |
d61fc448 PP |
127 | print_symbol(KERN_EMERG "faulting IP is at %s\n", regs->ip); |
128 | print_symbol(KERN_EMERG "last faulting IP was at %s\n", my_reason->ip); | |
8b7d89d0 | 129 | #ifdef __i386__ |
0fd0e3da | 130 | pr_emerg("eax: %08lx ebx: %08lx ecx: %08lx edx: %08lx\n", |
3a0340be | 131 | regs->ax, regs->bx, regs->cx, regs->dx); |
0fd0e3da | 132 | pr_emerg("esi: %08lx edi: %08lx ebp: %08lx esp: %08lx\n", |
3a0340be | 133 | regs->si, regs->di, regs->bp, regs->sp); |
8b7d89d0 | 134 | #else |
0fd0e3da | 135 | pr_emerg("rax: %016lx rcx: %016lx rdx: %016lx\n", |
3a0340be | 136 | regs->ax, regs->cx, regs->dx); |
0fd0e3da | 137 | pr_emerg("rsi: %016lx rdi: %016lx rbp: %016lx rsp: %016lx\n", |
3a0340be | 138 | regs->si, regs->di, regs->bp, regs->sp); |
8b7d89d0 | 139 | #endif |
f5136380 | 140 | put_cpu_var(pf_reason); |
8b7d89d0 PP |
141 | BUG(); |
142 | } | |
143 | ||
144 | static void pre(struct kmmio_probe *p, struct pt_regs *regs, | |
145 | unsigned long addr) | |
146 | { | |
f5136380 | 147 | struct trap_reason *my_reason = &get_cpu_var(pf_reason); |
bd8ac686 | 148 | struct mmiotrace_rw *my_trace = &get_cpu_var(cpu_trace); |
8b7d89d0 PP |
149 | const unsigned long instptr = instruction_pointer(regs); |
150 | const enum reason_type type = get_ins_type(instptr); | |
a50445d7 | 151 | struct remap_trace *trace = p->private; |
8b7d89d0 PP |
152 | |
153 | /* it doesn't make sense to have more than one active trace per cpu */ | |
f5136380 | 154 | if (my_reason->active_traces) |
8b7d89d0 PP |
155 | die_kmmio_nesting_error(regs, addr); |
156 | else | |
f5136380 | 157 | my_reason->active_traces++; |
8b7d89d0 | 158 | |
f5136380 PP |
159 | my_reason->type = type; |
160 | my_reason->addr = addr; | |
161 | my_reason->ip = instptr; | |
8b7d89d0 | 162 | |
bd8ac686 PP |
163 | my_trace->phys = addr - trace->probe.addr + trace->phys; |
164 | my_trace->map_id = trace->id; | |
8b7d89d0 PP |
165 | |
166 | /* | |
167 | * Only record the program counter when requested. | |
168 | * It may taint clean-room reverse engineering. | |
169 | */ | |
170 | if (trace_pc) | |
bd8ac686 | 171 | my_trace->pc = instptr; |
8b7d89d0 | 172 | else |
bd8ac686 | 173 | my_trace->pc = 0; |
8b7d89d0 | 174 | |
f984b51e PP |
175 | /* |
176 | * XXX: the timestamp recorded will be *after* the tracing has been | |
177 | * done, not at the time we hit the instruction. SMP implications | |
178 | * on event ordering? | |
179 | */ | |
8b7d89d0 PP |
180 | |
181 | switch (type) { | |
182 | case REG_READ: | |
bd8ac686 PP |
183 | my_trace->opcode = MMIO_READ; |
184 | my_trace->width = get_ins_mem_width(instptr); | |
8b7d89d0 PP |
185 | break; |
186 | case REG_WRITE: | |
bd8ac686 PP |
187 | my_trace->opcode = MMIO_WRITE; |
188 | my_trace->width = get_ins_mem_width(instptr); | |
189 | my_trace->value = get_ins_reg_val(instptr, regs); | |
8b7d89d0 PP |
190 | break; |
191 | case IMM_WRITE: | |
bd8ac686 PP |
192 | my_trace->opcode = MMIO_WRITE; |
193 | my_trace->width = get_ins_mem_width(instptr); | |
194 | my_trace->value = get_ins_imm_val(instptr); | |
8b7d89d0 PP |
195 | break; |
196 | default: | |
197 | { | |
198 | unsigned char *ip = (unsigned char *)instptr; | |
bd8ac686 PP |
199 | my_trace->opcode = MMIO_UNKNOWN_OP; |
200 | my_trace->width = 0; | |
201 | my_trace->value = (*ip) << 16 | *(ip + 1) << 8 | | |
f5136380 | 202 | *(ip + 2); |
8b7d89d0 PP |
203 | } |
204 | } | |
f5136380 PP |
205 | put_cpu_var(cpu_trace); |
206 | put_cpu_var(pf_reason); | |
8b7d89d0 PP |
207 | } |
208 | ||
209 | static void post(struct kmmio_probe *p, unsigned long condition, | |
210 | struct pt_regs *regs) | |
211 | { | |
f5136380 | 212 | struct trap_reason *my_reason = &get_cpu_var(pf_reason); |
bd8ac686 | 213 | struct mmiotrace_rw *my_trace = &get_cpu_var(cpu_trace); |
8b7d89d0 PP |
214 | |
215 | /* this should always return the active_trace count to 0 */ | |
f5136380 PP |
216 | my_reason->active_traces--; |
217 | if (my_reason->active_traces) { | |
3a0340be | 218 | pr_emerg("unexpected post handler"); |
8b7d89d0 PP |
219 | BUG(); |
220 | } | |
221 | ||
f5136380 | 222 | switch (my_reason->type) { |
8b7d89d0 | 223 | case REG_READ: |
bd8ac686 | 224 | my_trace->value = get_ins_reg_val(my_reason->ip, regs); |
8b7d89d0 PP |
225 | break; |
226 | default: | |
227 | break; | |
228 | } | |
f984b51e | 229 | |
bd8ac686 | 230 | mmio_trace_rw(my_trace); |
f5136380 PP |
231 | put_cpu_var(cpu_trace); |
232 | put_cpu_var(pf_reason); | |
8b7d89d0 PP |
233 | } |
234 | ||
dee310d0 | 235 | static void ioremap_trace_core(resource_size_t offset, unsigned long size, |
8b7d89d0 PP |
236 | void __iomem *addr) |
237 | { | |
d61fc448 | 238 | static atomic_t next_id; |
8b7d89d0 | 239 | struct remap_trace *trace = kmalloc(sizeof(*trace), GFP_KERNEL); |
87e547fe | 240 | /* These are page-unaligned. */ |
bd8ac686 PP |
241 | struct mmiotrace_map map = { |
242 | .phys = offset, | |
243 | .virt = (unsigned long)addr, | |
244 | .len = size, | |
245 | .opcode = MMIO_PROBE | |
8b7d89d0 | 246 | }; |
8b7d89d0 | 247 | |
d61fc448 | 248 | if (!trace) { |
3a0340be | 249 | pr_err("kmalloc failed in ioremap\n"); |
d61fc448 PP |
250 | return; |
251 | } | |
252 | ||
8b7d89d0 PP |
253 | *trace = (struct remap_trace) { |
254 | .probe = { | |
255 | .addr = (unsigned long)addr, | |
256 | .len = size, | |
257 | .pre_handler = pre, | |
258 | .post_handler = post, | |
a50445d7 | 259 | .private = trace |
d61fc448 PP |
260 | }, |
261 | .phys = offset, | |
262 | .id = atomic_inc_return(&next_id) | |
8b7d89d0 | 263 | }; |
bd8ac686 | 264 | map.map_id = trace->id; |
8b7d89d0 | 265 | |
d61fc448 | 266 | spin_lock_irq(&trace_lock); |
bbe5c783 PP |
267 | if (!is_enabled()) { |
268 | kfree(trace); | |
d61fc448 | 269 | goto not_enabled; |
bbe5c783 | 270 | } |
d61fc448 | 271 | |
bd8ac686 | 272 | mmio_trace_mapping(&map); |
8b7d89d0 | 273 | list_add_tail(&trace->list, &trace_list); |
8b7d89d0 PP |
274 | if (!nommiotrace) |
275 | register_kmmio_probe(&trace->probe); | |
d61fc448 PP |
276 | |
277 | not_enabled: | |
278 | spin_unlock_irq(&trace_lock); | |
8b7d89d0 PP |
279 | } |
280 | ||
dee310d0 PP |
281 | void mmiotrace_ioremap(resource_size_t offset, unsigned long size, |
282 | void __iomem *addr) | |
8b7d89d0 | 283 | { |
d61fc448 | 284 | if (!is_enabled()) /* recheck and proper locking in *_core() */ |
8b7d89d0 PP |
285 | return; |
286 | ||
3a0340be JP |
287 | pr_debug("ioremap_*(0x%llx, 0x%lx) = %p\n", |
288 | (unsigned long long)offset, size, addr); | |
d61fc448 | 289 | if ((filter_offset) && (offset != filter_offset)) |
8b7d89d0 | 290 | return; |
d61fc448 | 291 | ioremap_trace_core(offset, size, addr); |
8b7d89d0 | 292 | } |
8b7d89d0 | 293 | |
d61fc448 | 294 | static void iounmap_trace_core(volatile void __iomem *addr) |
8b7d89d0 | 295 | { |
bd8ac686 PP |
296 | struct mmiotrace_map map = { |
297 | .phys = 0, | |
298 | .virt = (unsigned long)addr, | |
299 | .len = 0, | |
300 | .opcode = MMIO_UNPROBE | |
8b7d89d0 PP |
301 | }; |
302 | struct remap_trace *trace; | |
303 | struct remap_trace *tmp; | |
d61fc448 PP |
304 | struct remap_trace *found_trace = NULL; |
305 | ||
3a0340be | 306 | pr_debug("Unmapping %p.\n", addr); |
8b7d89d0 | 307 | |
d61fc448 PP |
308 | spin_lock_irq(&trace_lock); |
309 | if (!is_enabled()) | |
310 | goto not_enabled; | |
311 | ||
8b7d89d0 PP |
312 | list_for_each_entry_safe(trace, tmp, &trace_list, list) { |
313 | if ((unsigned long)addr == trace->probe.addr) { | |
314 | if (!nommiotrace) | |
315 | unregister_kmmio_probe(&trace->probe); | |
316 | list_del(&trace->list); | |
d61fc448 | 317 | found_trace = trace; |
8b7d89d0 PP |
318 | break; |
319 | } | |
320 | } | |
bd8ac686 PP |
321 | map.map_id = (found_trace) ? found_trace->id : -1; |
322 | mmio_trace_mapping(&map); | |
d61fc448 PP |
323 | |
324 | not_enabled: | |
325 | spin_unlock_irq(&trace_lock); | |
326 | if (found_trace) { | |
327 | synchronize_rcu(); /* unregister_kmmio_probe() requirement */ | |
328 | kfree(found_trace); | |
329 | } | |
330 | } | |
331 | ||
332 | void mmiotrace_iounmap(volatile void __iomem *addr) | |
333 | { | |
334 | might_sleep(); | |
335 | if (is_enabled()) /* recheck and proper locking in *_core() */ | |
336 | iounmap_trace_core(addr); | |
8b7d89d0 | 337 | } |
8b7d89d0 | 338 | |
9e57fb35 PP |
339 | int mmiotrace_printk(const char *fmt, ...) |
340 | { | |
341 | int ret = 0; | |
342 | va_list args; | |
343 | unsigned long flags; | |
344 | va_start(args, fmt); | |
345 | ||
346 | spin_lock_irqsave(&trace_lock, flags); | |
347 | if (is_enabled()) | |
348 | ret = mmio_trace_printk(fmt, args); | |
349 | spin_unlock_irqrestore(&trace_lock, flags); | |
350 | ||
351 | va_end(args); | |
352 | return ret; | |
353 | } | |
354 | EXPORT_SYMBOL(mmiotrace_printk); | |
355 | ||
8b7d89d0 PP |
356 | static void clear_trace_list(void) |
357 | { | |
358 | struct remap_trace *trace; | |
359 | struct remap_trace *tmp; | |
360 | ||
d61fc448 PP |
361 | /* |
362 | * No locking required, because the caller ensures we are in a | |
363 | * critical section via mutex, and is_enabled() is false, | |
364 | * i.e. nothing can traverse or modify this list. | |
365 | * Caller also ensures is_enabled() cannot change. | |
366 | */ | |
367 | list_for_each_entry(trace, &trace_list, list) { | |
3a0340be JP |
368 | pr_notice("purging non-iounmapped trace @0x%08lx, size 0x%lx.\n", |
369 | trace->probe.addr, trace->probe.len); | |
8b7d89d0 PP |
370 | if (!nommiotrace) |
371 | unregister_kmmio_probe(&trace->probe); | |
d61fc448 PP |
372 | } |
373 | synchronize_rcu(); /* unregister_kmmio_probe() requirement */ | |
374 | ||
375 | list_for_each_entry_safe(trace, tmp, &trace_list, list) { | |
8b7d89d0 PP |
376 | list_del(&trace->list); |
377 | kfree(trace); | |
d61fc448 PP |
378 | } |
379 | } | |
380 | ||
7423d111 | 381 | #ifdef CONFIG_HOTPLUG_CPU |
c38da569 | 382 | static cpumask_var_t downed_cpus; |
7423d111 PP |
383 | |
384 | static void enter_uniprocessor(void) | |
385 | { | |
386 | int cpu; | |
387 | int err; | |
388 | ||
c38da569 RR |
389 | if (downed_cpus == NULL && |
390 | !alloc_cpumask_var(&downed_cpus, GFP_KERNEL)) { | |
3a0340be | 391 | pr_notice("Failed to allocate mask\n"); |
c38da569 RR |
392 | goto out; |
393 | } | |
394 | ||
7423d111 | 395 | get_online_cpus(); |
c38da569 RR |
396 | cpumask_copy(downed_cpus, cpu_online_mask); |
397 | cpumask_clear_cpu(cpumask_first(cpu_online_mask), downed_cpus); | |
7423d111 | 398 | if (num_online_cpus() > 1) |
3a0340be | 399 | pr_notice("Disabling non-boot CPUs...\n"); |
7423d111 PP |
400 | put_online_cpus(); |
401 | ||
c38da569 | 402 | for_each_cpu(cpu, downed_cpus) { |
7423d111 | 403 | err = cpu_down(cpu); |
970e6fa0 | 404 | if (!err) |
3a0340be | 405 | pr_info("CPU%d is down.\n", cpu); |
970e6fa0 | 406 | else |
3a0340be | 407 | pr_err("Error taking CPU%d down: %d\n", cpu, err); |
7423d111 | 408 | } |
c38da569 | 409 | out: |
7423d111 | 410 | if (num_online_cpus() > 1) |
3a0340be | 411 | pr_warning("multiple CPUs still online, may miss events.\n"); |
7423d111 PP |
412 | } |
413 | ||
7701e8c5 MS |
414 | /* __ref because leave_uniprocessor calls cpu_up which is __cpuinit, |
415 | but this whole function is ifdefed CONFIG_HOTPLUG_CPU */ | |
416 | static void __ref leave_uniprocessor(void) | |
7423d111 PP |
417 | { |
418 | int cpu; | |
419 | int err; | |
420 | ||
c38da569 | 421 | if (downed_cpus == NULL || cpumask_weight(downed_cpus) == 0) |
7423d111 | 422 | return; |
3a0340be | 423 | pr_notice("Re-enabling CPUs...\n"); |
c38da569 | 424 | for_each_cpu(cpu, downed_cpus) { |
7423d111 PP |
425 | err = cpu_up(cpu); |
426 | if (!err) | |
3a0340be | 427 | pr_info("enabled CPU%d.\n", cpu); |
7423d111 | 428 | else |
3a0340be | 429 | pr_err("cannot re-enable CPU%d: %d\n", cpu, err); |
7423d111 PP |
430 | } |
431 | } | |
432 | ||
433 | #else /* !CONFIG_HOTPLUG_CPU */ | |
434 | static void enter_uniprocessor(void) | |
435 | { | |
436 | if (num_online_cpus() > 1) | |
3a0340be JP |
437 | pr_warning("multiple CPUs are online, may miss events. " |
438 | "Suggest booting with maxcpus=1 kernel argument.\n"); | |
7423d111 PP |
439 | } |
440 | ||
441 | static void leave_uniprocessor(void) | |
442 | { | |
443 | } | |
444 | #endif | |
445 | ||
f984b51e | 446 | void enable_mmiotrace(void) |
d61fc448 PP |
447 | { |
448 | mutex_lock(&mmiotrace_mutex); | |
449 | if (is_enabled()) | |
450 | goto out; | |
451 | ||
d61fc448 | 452 | if (nommiotrace) |
3a0340be | 453 | pr_info("MMIO tracing disabled.\n"); |
0f9a623d | 454 | kmmio_init(); |
7423d111 | 455 | enter_uniprocessor(); |
d61fc448 PP |
456 | spin_lock_irq(&trace_lock); |
457 | atomic_inc(&mmiotrace_enabled); | |
458 | spin_unlock_irq(&trace_lock); | |
3a0340be | 459 | pr_info("enabled.\n"); |
d61fc448 PP |
460 | out: |
461 | mutex_unlock(&mmiotrace_mutex); | |
462 | } | |
463 | ||
f984b51e | 464 | void disable_mmiotrace(void) |
d61fc448 PP |
465 | { |
466 | mutex_lock(&mmiotrace_mutex); | |
467 | if (!is_enabled()) | |
468 | goto out; | |
469 | ||
470 | spin_lock_irq(&trace_lock); | |
471 | atomic_dec(&mmiotrace_enabled); | |
472 | BUG_ON(is_enabled()); | |
473 | spin_unlock_irq(&trace_lock); | |
474 | ||
475 | clear_trace_list(); /* guarantees: no more kmmio callbacks */ | |
7423d111 | 476 | leave_uniprocessor(); |
0f9a623d | 477 | kmmio_cleanup(); |
3a0340be | 478 | pr_info("disabled.\n"); |
d61fc448 PP |
479 | out: |
480 | mutex_unlock(&mmiotrace_mutex); | |
8b7d89d0 | 481 | } |