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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/kallsyms.h> |
33 | #include <asm/pgtable.h> | |
34 | #include <linux/mmiotrace.h> | |
35 | #include <asm/e820.h> /* for ISA_START_ADDRESS */ | |
60063497 | 36 | #include <linux/atomic.h> |
f5136380 | 37 | #include <linux/percpu.h> |
7423d111 | 38 | #include <linux/cpu.h> |
8b7d89d0 | 39 | |
8b7d89d0 PP |
40 | #include "pf_in.h" |
41 | ||
8b7d89d0 PP |
42 | struct trap_reason { |
43 | unsigned long addr; | |
44 | unsigned long ip; | |
45 | enum reason_type type; | |
46 | int active_traces; | |
47 | }; | |
48 | ||
d61fc448 PP |
49 | struct remap_trace { |
50 | struct list_head list; | |
51 | struct kmmio_probe probe; | |
dee310d0 | 52 | resource_size_t phys; |
d61fc448 PP |
53 | unsigned long id; |
54 | }; | |
55 | ||
fe1ffafa | 56 | /* Accessed per-cpu. */ |
f5136380 | 57 | static DEFINE_PER_CPU(struct trap_reason, pf_reason); |
bd8ac686 | 58 | static DEFINE_PER_CPU(struct mmiotrace_rw, cpu_trace); |
8b7d89d0 | 59 | |
d61fc448 PP |
60 | static DEFINE_MUTEX(mmiotrace_mutex); |
61 | static DEFINE_SPINLOCK(trace_lock); | |
62 | static atomic_t mmiotrace_enabled; | |
63 | static LIST_HEAD(trace_list); /* struct remap_trace */ | |
d61fc448 PP |
64 | |
65 | /* | |
66 | * Locking in this file: | |
67 | * - mmiotrace_mutex enforces enable/disable_mmiotrace() critical sections. | |
68 | * - mmiotrace_enabled may be modified only when holding mmiotrace_mutex | |
69 | * and trace_lock. | |
70 | * - Routines depending on is_enabled() must take trace_lock. | |
71 | * - trace_list users must hold trace_lock. | |
9e57fb35 | 72 | * - is_enabled() guarantees that mmio_trace_{rw,mapping} are allowed. |
d61fc448 PP |
73 | * - pre/post callbacks assume the effect of is_enabled() being true. |
74 | */ | |
8b7d89d0 PP |
75 | |
76 | /* module parameters */ | |
d61fc448 | 77 | static unsigned long filter_offset; |
476bc001 RR |
78 | static bool nommiotrace; |
79 | static bool trace_pc; | |
8b7d89d0 | 80 | |
8b7d89d0 PP |
81 | module_param(filter_offset, ulong, 0); |
82 | module_param(nommiotrace, bool, 0); | |
8b7d89d0 PP |
83 | module_param(trace_pc, bool, 0); |
84 | ||
8b7d89d0 PP |
85 | MODULE_PARM_DESC(filter_offset, "Start address of traced mappings."); |
86 | MODULE_PARM_DESC(nommiotrace, "Disable actual MMIO tracing."); | |
8b7d89d0 | 87 | MODULE_PARM_DESC(trace_pc, "Record address of faulting instructions."); |
d61fc448 PP |
88 | |
89 | static bool is_enabled(void) | |
90 | { | |
91 | return atomic_read(&mmiotrace_enabled); | |
92 | } | |
8b7d89d0 | 93 | |
8b7d89d0 PP |
94 | static void print_pte(unsigned long address) |
95 | { | |
790e2a29 | 96 | unsigned int level; |
75bb8835 PP |
97 | pte_t *pte = lookup_address(address, &level); |
98 | ||
99 | if (!pte) { | |
3a0340be JP |
100 | pr_err("Error in %s: no pte for page 0x%08lx\n", |
101 | __func__, address); | |
75bb8835 PP |
102 | return; |
103 | } | |
104 | ||
105 | if (level == PG_LEVEL_2M) { | |
3a0340be JP |
106 | pr_emerg("4MB pages are not currently supported: 0x%08lx\n", |
107 | address); | |
8b7d89d0 PP |
108 | BUG(); |
109 | } | |
3a0340be JP |
110 | pr_info("pte for 0x%lx: 0x%llx 0x%llx\n", |
111 | address, | |
0663bb6c RD |
112 | (unsigned long long)pte_val(*pte), |
113 | (unsigned long long)pte_val(*pte) & _PAGE_PRESENT); | |
8b7d89d0 PP |
114 | } |
115 | ||
116 | /* | |
117 | * For some reason the pre/post pairs have been called in an | |
118 | * unmatched order. Report and die. | |
119 | */ | |
120 | static void die_kmmio_nesting_error(struct pt_regs *regs, unsigned long addr) | |
121 | { | |
f5136380 | 122 | const struct trap_reason *my_reason = &get_cpu_var(pf_reason); |
3a0340be JP |
123 | pr_emerg("unexpected fault for address: 0x%08lx, last fault for address: 0x%08lx\n", |
124 | addr, my_reason->addr); | |
8b7d89d0 | 125 | print_pte(addr); |
d61fc448 PP |
126 | print_symbol(KERN_EMERG "faulting IP is at %s\n", regs->ip); |
127 | print_symbol(KERN_EMERG "last faulting IP was at %s\n", my_reason->ip); | |
8b7d89d0 | 128 | #ifdef __i386__ |
0fd0e3da | 129 | pr_emerg("eax: %08lx ebx: %08lx ecx: %08lx edx: %08lx\n", |
3a0340be | 130 | regs->ax, regs->bx, regs->cx, regs->dx); |
0fd0e3da | 131 | pr_emerg("esi: %08lx edi: %08lx ebp: %08lx esp: %08lx\n", |
3a0340be | 132 | regs->si, regs->di, regs->bp, regs->sp); |
8b7d89d0 | 133 | #else |
0fd0e3da | 134 | pr_emerg("rax: %016lx rcx: %016lx rdx: %016lx\n", |
3a0340be | 135 | regs->ax, regs->cx, regs->dx); |
0fd0e3da | 136 | pr_emerg("rsi: %016lx rdi: %016lx rbp: %016lx rsp: %016lx\n", |
3a0340be | 137 | regs->si, regs->di, regs->bp, regs->sp); |
8b7d89d0 | 138 | #endif |
f5136380 | 139 | put_cpu_var(pf_reason); |
8b7d89d0 PP |
140 | BUG(); |
141 | } | |
142 | ||
143 | static void pre(struct kmmio_probe *p, struct pt_regs *regs, | |
144 | unsigned long addr) | |
145 | { | |
f5136380 | 146 | struct trap_reason *my_reason = &get_cpu_var(pf_reason); |
bd8ac686 | 147 | struct mmiotrace_rw *my_trace = &get_cpu_var(cpu_trace); |
8b7d89d0 PP |
148 | const unsigned long instptr = instruction_pointer(regs); |
149 | const enum reason_type type = get_ins_type(instptr); | |
a50445d7 | 150 | struct remap_trace *trace = p->private; |
8b7d89d0 PP |
151 | |
152 | /* it doesn't make sense to have more than one active trace per cpu */ | |
f5136380 | 153 | if (my_reason->active_traces) |
8b7d89d0 PP |
154 | die_kmmio_nesting_error(regs, addr); |
155 | else | |
f5136380 | 156 | my_reason->active_traces++; |
8b7d89d0 | 157 | |
f5136380 PP |
158 | my_reason->type = type; |
159 | my_reason->addr = addr; | |
160 | my_reason->ip = instptr; | |
8b7d89d0 | 161 | |
bd8ac686 PP |
162 | my_trace->phys = addr - trace->probe.addr + trace->phys; |
163 | my_trace->map_id = trace->id; | |
8b7d89d0 PP |
164 | |
165 | /* | |
166 | * Only record the program counter when requested. | |
167 | * It may taint clean-room reverse engineering. | |
168 | */ | |
169 | if (trace_pc) | |
bd8ac686 | 170 | my_trace->pc = instptr; |
8b7d89d0 | 171 | else |
bd8ac686 | 172 | my_trace->pc = 0; |
8b7d89d0 | 173 | |
f984b51e PP |
174 | /* |
175 | * XXX: the timestamp recorded will be *after* the tracing has been | |
176 | * done, not at the time we hit the instruction. SMP implications | |
177 | * on event ordering? | |
178 | */ | |
8b7d89d0 PP |
179 | |
180 | switch (type) { | |
181 | case REG_READ: | |
bd8ac686 PP |
182 | my_trace->opcode = MMIO_READ; |
183 | my_trace->width = get_ins_mem_width(instptr); | |
8b7d89d0 PP |
184 | break; |
185 | case REG_WRITE: | |
bd8ac686 PP |
186 | my_trace->opcode = MMIO_WRITE; |
187 | my_trace->width = get_ins_mem_width(instptr); | |
188 | my_trace->value = get_ins_reg_val(instptr, regs); | |
8b7d89d0 PP |
189 | break; |
190 | case IMM_WRITE: | |
bd8ac686 PP |
191 | my_trace->opcode = MMIO_WRITE; |
192 | my_trace->width = get_ins_mem_width(instptr); | |
193 | my_trace->value = get_ins_imm_val(instptr); | |
8b7d89d0 PP |
194 | break; |
195 | default: | |
196 | { | |
197 | unsigned char *ip = (unsigned char *)instptr; | |
bd8ac686 PP |
198 | my_trace->opcode = MMIO_UNKNOWN_OP; |
199 | my_trace->width = 0; | |
200 | my_trace->value = (*ip) << 16 | *(ip + 1) << 8 | | |
f5136380 | 201 | *(ip + 2); |
8b7d89d0 PP |
202 | } |
203 | } | |
f5136380 PP |
204 | put_cpu_var(cpu_trace); |
205 | put_cpu_var(pf_reason); | |
8b7d89d0 PP |
206 | } |
207 | ||
208 | static void post(struct kmmio_probe *p, unsigned long condition, | |
209 | struct pt_regs *regs) | |
210 | { | |
f5136380 | 211 | struct trap_reason *my_reason = &get_cpu_var(pf_reason); |
bd8ac686 | 212 | struct mmiotrace_rw *my_trace = &get_cpu_var(cpu_trace); |
8b7d89d0 PP |
213 | |
214 | /* this should always return the active_trace count to 0 */ | |
f5136380 PP |
215 | my_reason->active_traces--; |
216 | if (my_reason->active_traces) { | |
3a0340be | 217 | pr_emerg("unexpected post handler"); |
8b7d89d0 PP |
218 | BUG(); |
219 | } | |
220 | ||
f5136380 | 221 | switch (my_reason->type) { |
8b7d89d0 | 222 | case REG_READ: |
bd8ac686 | 223 | my_trace->value = get_ins_reg_val(my_reason->ip, regs); |
8b7d89d0 PP |
224 | break; |
225 | default: | |
226 | break; | |
227 | } | |
f984b51e | 228 | |
bd8ac686 | 229 | mmio_trace_rw(my_trace); |
f5136380 PP |
230 | put_cpu_var(cpu_trace); |
231 | put_cpu_var(pf_reason); | |
8b7d89d0 PP |
232 | } |
233 | ||
dee310d0 | 234 | static void ioremap_trace_core(resource_size_t offset, unsigned long size, |
8b7d89d0 PP |
235 | void __iomem *addr) |
236 | { | |
d61fc448 | 237 | static atomic_t next_id; |
8b7d89d0 | 238 | struct remap_trace *trace = kmalloc(sizeof(*trace), GFP_KERNEL); |
87e547fe | 239 | /* These are page-unaligned. */ |
bd8ac686 PP |
240 | struct mmiotrace_map map = { |
241 | .phys = offset, | |
242 | .virt = (unsigned long)addr, | |
243 | .len = size, | |
244 | .opcode = MMIO_PROBE | |
8b7d89d0 | 245 | }; |
8b7d89d0 | 246 | |
d61fc448 | 247 | if (!trace) { |
3a0340be | 248 | pr_err("kmalloc failed in ioremap\n"); |
d61fc448 PP |
249 | return; |
250 | } | |
251 | ||
8b7d89d0 PP |
252 | *trace = (struct remap_trace) { |
253 | .probe = { | |
254 | .addr = (unsigned long)addr, | |
255 | .len = size, | |
256 | .pre_handler = pre, | |
257 | .post_handler = post, | |
a50445d7 | 258 | .private = trace |
d61fc448 PP |
259 | }, |
260 | .phys = offset, | |
261 | .id = atomic_inc_return(&next_id) | |
8b7d89d0 | 262 | }; |
bd8ac686 | 263 | map.map_id = trace->id; |
8b7d89d0 | 264 | |
d61fc448 | 265 | spin_lock_irq(&trace_lock); |
bbe5c783 PP |
266 | if (!is_enabled()) { |
267 | kfree(trace); | |
d61fc448 | 268 | goto not_enabled; |
bbe5c783 | 269 | } |
d61fc448 | 270 | |
bd8ac686 | 271 | mmio_trace_mapping(&map); |
8b7d89d0 | 272 | list_add_tail(&trace->list, &trace_list); |
8b7d89d0 PP |
273 | if (!nommiotrace) |
274 | register_kmmio_probe(&trace->probe); | |
d61fc448 PP |
275 | |
276 | not_enabled: | |
277 | spin_unlock_irq(&trace_lock); | |
8b7d89d0 PP |
278 | } |
279 | ||
dee310d0 PP |
280 | void mmiotrace_ioremap(resource_size_t offset, unsigned long size, |
281 | void __iomem *addr) | |
8b7d89d0 | 282 | { |
d61fc448 | 283 | if (!is_enabled()) /* recheck and proper locking in *_core() */ |
8b7d89d0 PP |
284 | return; |
285 | ||
3a0340be JP |
286 | pr_debug("ioremap_*(0x%llx, 0x%lx) = %p\n", |
287 | (unsigned long long)offset, size, addr); | |
d61fc448 | 288 | if ((filter_offset) && (offset != filter_offset)) |
8b7d89d0 | 289 | return; |
d61fc448 | 290 | ioremap_trace_core(offset, size, addr); |
8b7d89d0 | 291 | } |
8b7d89d0 | 292 | |
d61fc448 | 293 | static void iounmap_trace_core(volatile void __iomem *addr) |
8b7d89d0 | 294 | { |
bd8ac686 PP |
295 | struct mmiotrace_map map = { |
296 | .phys = 0, | |
297 | .virt = (unsigned long)addr, | |
298 | .len = 0, | |
299 | .opcode = MMIO_UNPROBE | |
8b7d89d0 PP |
300 | }; |
301 | struct remap_trace *trace; | |
302 | struct remap_trace *tmp; | |
d61fc448 PP |
303 | struct remap_trace *found_trace = NULL; |
304 | ||
3a0340be | 305 | pr_debug("Unmapping %p.\n", addr); |
8b7d89d0 | 306 | |
d61fc448 PP |
307 | spin_lock_irq(&trace_lock); |
308 | if (!is_enabled()) | |
309 | goto not_enabled; | |
310 | ||
8b7d89d0 PP |
311 | list_for_each_entry_safe(trace, tmp, &trace_list, list) { |
312 | if ((unsigned long)addr == trace->probe.addr) { | |
313 | if (!nommiotrace) | |
314 | unregister_kmmio_probe(&trace->probe); | |
315 | list_del(&trace->list); | |
d61fc448 | 316 | found_trace = trace; |
8b7d89d0 PP |
317 | break; |
318 | } | |
319 | } | |
bd8ac686 PP |
320 | map.map_id = (found_trace) ? found_trace->id : -1; |
321 | mmio_trace_mapping(&map); | |
d61fc448 PP |
322 | |
323 | not_enabled: | |
324 | spin_unlock_irq(&trace_lock); | |
325 | if (found_trace) { | |
326 | synchronize_rcu(); /* unregister_kmmio_probe() requirement */ | |
327 | kfree(found_trace); | |
328 | } | |
329 | } | |
330 | ||
331 | void mmiotrace_iounmap(volatile void __iomem *addr) | |
332 | { | |
333 | might_sleep(); | |
334 | if (is_enabled()) /* recheck and proper locking in *_core() */ | |
335 | iounmap_trace_core(addr); | |
8b7d89d0 | 336 | } |
8b7d89d0 | 337 | |
9e57fb35 PP |
338 | int mmiotrace_printk(const char *fmt, ...) |
339 | { | |
340 | int ret = 0; | |
341 | va_list args; | |
342 | unsigned long flags; | |
343 | va_start(args, fmt); | |
344 | ||
345 | spin_lock_irqsave(&trace_lock, flags); | |
346 | if (is_enabled()) | |
347 | ret = mmio_trace_printk(fmt, args); | |
348 | spin_unlock_irqrestore(&trace_lock, flags); | |
349 | ||
350 | va_end(args); | |
351 | return ret; | |
352 | } | |
353 | EXPORT_SYMBOL(mmiotrace_printk); | |
354 | ||
8b7d89d0 PP |
355 | static void clear_trace_list(void) |
356 | { | |
357 | struct remap_trace *trace; | |
358 | struct remap_trace *tmp; | |
359 | ||
d61fc448 PP |
360 | /* |
361 | * No locking required, because the caller ensures we are in a | |
362 | * critical section via mutex, and is_enabled() is false, | |
363 | * i.e. nothing can traverse or modify this list. | |
364 | * Caller also ensures is_enabled() cannot change. | |
365 | */ | |
366 | list_for_each_entry(trace, &trace_list, list) { | |
3a0340be JP |
367 | pr_notice("purging non-iounmapped trace @0x%08lx, size 0x%lx.\n", |
368 | trace->probe.addr, trace->probe.len); | |
8b7d89d0 PP |
369 | if (!nommiotrace) |
370 | unregister_kmmio_probe(&trace->probe); | |
d61fc448 PP |
371 | } |
372 | synchronize_rcu(); /* unregister_kmmio_probe() requirement */ | |
373 | ||
374 | list_for_each_entry_safe(trace, tmp, &trace_list, list) { | |
8b7d89d0 PP |
375 | list_del(&trace->list); |
376 | kfree(trace); | |
d61fc448 PP |
377 | } |
378 | } | |
379 | ||
7423d111 | 380 | #ifdef CONFIG_HOTPLUG_CPU |
c38da569 | 381 | static cpumask_var_t downed_cpus; |
7423d111 PP |
382 | |
383 | static void enter_uniprocessor(void) | |
384 | { | |
385 | int cpu; | |
386 | int err; | |
387 | ||
c38da569 RR |
388 | if (downed_cpus == NULL && |
389 | !alloc_cpumask_var(&downed_cpus, GFP_KERNEL)) { | |
3a0340be | 390 | pr_notice("Failed to allocate mask\n"); |
c38da569 RR |
391 | goto out; |
392 | } | |
393 | ||
7423d111 | 394 | get_online_cpus(); |
c38da569 RR |
395 | cpumask_copy(downed_cpus, cpu_online_mask); |
396 | cpumask_clear_cpu(cpumask_first(cpu_online_mask), downed_cpus); | |
7423d111 | 397 | if (num_online_cpus() > 1) |
3a0340be | 398 | pr_notice("Disabling non-boot CPUs...\n"); |
7423d111 PP |
399 | put_online_cpus(); |
400 | ||
c38da569 | 401 | for_each_cpu(cpu, downed_cpus) { |
7423d111 | 402 | err = cpu_down(cpu); |
970e6fa0 | 403 | if (!err) |
3a0340be | 404 | pr_info("CPU%d is down.\n", cpu); |
970e6fa0 | 405 | else |
3a0340be | 406 | pr_err("Error taking CPU%d down: %d\n", cpu, err); |
7423d111 | 407 | } |
c38da569 | 408 | out: |
7423d111 | 409 | if (num_online_cpus() > 1) |
3a0340be | 410 | pr_warning("multiple CPUs still online, may miss events.\n"); |
7423d111 PP |
411 | } |
412 | ||
148f9bb8 | 413 | static void leave_uniprocessor(void) |
7423d111 PP |
414 | { |
415 | int cpu; | |
416 | int err; | |
417 | ||
c38da569 | 418 | if (downed_cpus == NULL || cpumask_weight(downed_cpus) == 0) |
7423d111 | 419 | return; |
3a0340be | 420 | pr_notice("Re-enabling CPUs...\n"); |
c38da569 | 421 | for_each_cpu(cpu, downed_cpus) { |
7423d111 PP |
422 | err = cpu_up(cpu); |
423 | if (!err) | |
3a0340be | 424 | pr_info("enabled CPU%d.\n", cpu); |
7423d111 | 425 | else |
3a0340be | 426 | pr_err("cannot re-enable CPU%d: %d\n", cpu, err); |
7423d111 PP |
427 | } |
428 | } | |
429 | ||
430 | #else /* !CONFIG_HOTPLUG_CPU */ | |
431 | static void enter_uniprocessor(void) | |
432 | { | |
433 | if (num_online_cpus() > 1) | |
3a0340be JP |
434 | pr_warning("multiple CPUs are online, may miss events. " |
435 | "Suggest booting with maxcpus=1 kernel argument.\n"); | |
7423d111 PP |
436 | } |
437 | ||
438 | static void leave_uniprocessor(void) | |
439 | { | |
440 | } | |
441 | #endif | |
442 | ||
f984b51e | 443 | void enable_mmiotrace(void) |
d61fc448 PP |
444 | { |
445 | mutex_lock(&mmiotrace_mutex); | |
446 | if (is_enabled()) | |
447 | goto out; | |
448 | ||
d61fc448 | 449 | if (nommiotrace) |
3a0340be | 450 | pr_info("MMIO tracing disabled.\n"); |
0f9a623d | 451 | kmmio_init(); |
7423d111 | 452 | enter_uniprocessor(); |
d61fc448 PP |
453 | spin_lock_irq(&trace_lock); |
454 | atomic_inc(&mmiotrace_enabled); | |
455 | spin_unlock_irq(&trace_lock); | |
3a0340be | 456 | pr_info("enabled.\n"); |
d61fc448 PP |
457 | out: |
458 | mutex_unlock(&mmiotrace_mutex); | |
459 | } | |
460 | ||
f984b51e | 461 | void disable_mmiotrace(void) |
d61fc448 PP |
462 | { |
463 | mutex_lock(&mmiotrace_mutex); | |
464 | if (!is_enabled()) | |
465 | goto out; | |
466 | ||
467 | spin_lock_irq(&trace_lock); | |
468 | atomic_dec(&mmiotrace_enabled); | |
469 | BUG_ON(is_enabled()); | |
470 | spin_unlock_irq(&trace_lock); | |
471 | ||
472 | clear_trace_list(); /* guarantees: no more kmmio callbacks */ | |
7423d111 | 473 | leave_uniprocessor(); |
0f9a623d | 474 | kmmio_cleanup(); |
3a0340be | 475 | pr_info("disabled.\n"); |
d61fc448 PP |
476 | out: |
477 | mutex_unlock(&mmiotrace_mutex); | |
8b7d89d0 | 478 | } |