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