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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *
4 * Copyright (C) IBM Corporation, 2005
5 * Jeff Muizelaar, 2006, 2007
6 * Pekka Paalanen, 2008 <pq@iki.fi>
7 *
8 * Derived from the read-mod example from relay-examples by Tom Zanussi.
9 */
10
11#define pr_fmt(fmt) "mmiotrace: " fmt
12
13#include <linux/moduleparam.h>
14#include <linux/debugfs.h>
15#include <linux/slab.h>
16#include <linux/uaccess.h>
17#include <linux/io.h>
18#include <linux/mmiotrace.h>
19#include <linux/pgtable.h>
20#include <asm/e820/api.h> /* for ISA_START_ADDRESS */
21#include <linux/atomic.h>
22#include <linux/percpu.h>
23#include <linux/cpu.h>
24
25#include "pf_in.h"
26
27struct trap_reason {
28 unsigned long addr;
29 unsigned long ip;
30 enum reason_type type;
31 int active_traces;
32};
33
34struct remap_trace {
35 struct list_head list;
36 struct kmmio_probe probe;
37 resource_size_t phys;
38 unsigned long id;
39};
40
41/* Accessed per-cpu. */
42static DEFINE_PER_CPU(struct trap_reason, pf_reason);
43static DEFINE_PER_CPU(struct mmiotrace_rw, cpu_trace);
44
45static DEFINE_MUTEX(mmiotrace_mutex);
46static DEFINE_SPINLOCK(trace_lock);
47static atomic_t mmiotrace_enabled;
48static LIST_HEAD(trace_list); /* struct remap_trace */
49
50/*
51 * Locking in this file:
52 * - mmiotrace_mutex enforces enable/disable_mmiotrace() critical sections.
53 * - mmiotrace_enabled may be modified only when holding mmiotrace_mutex
54 * and trace_lock.
55 * - Routines depending on is_enabled() must take trace_lock.
56 * - trace_list users must hold trace_lock.
57 * - is_enabled() guarantees that mmio_trace_{rw,mapping} are allowed.
58 * - pre/post callbacks assume the effect of is_enabled() being true.
59 */
60
61/* module parameters */
62static unsigned long filter_offset;
63static bool nommiotrace;
64static bool trace_pc;
65
66module_param(filter_offset, ulong, 0);
67module_param(nommiotrace, bool, 0);
68module_param(trace_pc, bool, 0);
69
70MODULE_PARM_DESC(filter_offset, "Start address of traced mappings.");
71MODULE_PARM_DESC(nommiotrace, "Disable actual MMIO tracing.");
72MODULE_PARM_DESC(trace_pc, "Record address of faulting instructions.");
73
74static bool is_enabled(void)
75{
76 return atomic_read(&mmiotrace_enabled);
77}
78
79static void print_pte(unsigned long address)
80{
81 unsigned int level;
82 pte_t *pte = lookup_address(address, &level);
83
84 if (!pte) {
85 pr_err("Error in %s: no pte for page 0x%08lx\n",
86 __func__, address);
87 return;
88 }
89
90 if (level == PG_LEVEL_2M) {
91 pr_emerg("4MB pages are not currently supported: 0x%08lx\n",
92 address);
93 BUG();
94 }
95 pr_info("pte for 0x%lx: 0x%llx 0x%llx\n",
96 address,
97 (unsigned long long)pte_val(*pte),
98 (unsigned long long)pte_val(*pte) & _PAGE_PRESENT);
99}
100
101/*
102 * For some reason the pre/post pairs have been called in an
103 * unmatched order. Report and die.
104 */
105static void die_kmmio_nesting_error(struct pt_regs *regs, unsigned long addr)
106{
107 const struct trap_reason *my_reason = &get_cpu_var(pf_reason);
108 pr_emerg("unexpected fault for address: 0x%08lx, last fault for address: 0x%08lx\n",
109 addr, my_reason->addr);
110 print_pte(addr);
111 pr_emerg("faulting IP is at %pS\n", (void *)regs->ip);
112 pr_emerg("last faulting IP was at %pS\n", (void *)my_reason->ip);
113#ifdef __i386__
114 pr_emerg("eax: %08lx ebx: %08lx ecx: %08lx edx: %08lx\n",
115 regs->ax, regs->bx, regs->cx, regs->dx);
116 pr_emerg("esi: %08lx edi: %08lx ebp: %08lx esp: %08lx\n",
117 regs->si, regs->di, regs->bp, regs->sp);
118#else
119 pr_emerg("rax: %016lx rcx: %016lx rdx: %016lx\n",
120 regs->ax, regs->cx, regs->dx);
121 pr_emerg("rsi: %016lx rdi: %016lx rbp: %016lx rsp: %016lx\n",
122 regs->si, regs->di, regs->bp, regs->sp);
123#endif
124 put_cpu_var(pf_reason);
125 BUG();
126}
127
128static void pre(struct kmmio_probe *p, struct pt_regs *regs,
129 unsigned long addr)
130{
131 struct trap_reason *my_reason = &get_cpu_var(pf_reason);
132 struct mmiotrace_rw *my_trace = &get_cpu_var(cpu_trace);
133 const unsigned long instptr = instruction_pointer(regs);
134 const enum reason_type type = get_ins_type(instptr);
135 struct remap_trace *trace = p->private;
136
137 /* it doesn't make sense to have more than one active trace per cpu */
138 if (my_reason->active_traces)
139 die_kmmio_nesting_error(regs, addr);
140 else
141 my_reason->active_traces++;
142
143 my_reason->type = type;
144 my_reason->addr = addr;
145 my_reason->ip = instptr;
146
147 my_trace->phys = addr - trace->probe.addr + trace->phys;
148 my_trace->map_id = trace->id;
149
150 /*
151 * Only record the program counter when requested.
152 * It may taint clean-room reverse engineering.
153 */
154 if (trace_pc)
155 my_trace->pc = instptr;
156 else
157 my_trace->pc = 0;
158
159 /*
160 * XXX: the timestamp recorded will be *after* the tracing has been
161 * done, not at the time we hit the instruction. SMP implications
162 * on event ordering?
163 */
164
165 switch (type) {
166 case REG_READ:
167 my_trace->opcode = MMIO_READ;
168 my_trace->width = get_ins_mem_width(instptr);
169 break;
170 case REG_WRITE:
171 my_trace->opcode = MMIO_WRITE;
172 my_trace->width = get_ins_mem_width(instptr);
173 my_trace->value = get_ins_reg_val(instptr, regs);
174 break;
175 case IMM_WRITE:
176 my_trace->opcode = MMIO_WRITE;
177 my_trace->width = get_ins_mem_width(instptr);
178 my_trace->value = get_ins_imm_val(instptr);
179 break;
180 default:
181 {
182 unsigned char *ip = (unsigned char *)instptr;
183 my_trace->opcode = MMIO_UNKNOWN_OP;
184 my_trace->width = 0;
185 my_trace->value = (*ip) << 16 | *(ip + 1) << 8 |
186 *(ip + 2);
187 }
188 }
189 put_cpu_var(cpu_trace);
190 put_cpu_var(pf_reason);
191}
192
193static void post(struct kmmio_probe *p, unsigned long condition,
194 struct pt_regs *regs)
195{
196 struct trap_reason *my_reason = &get_cpu_var(pf_reason);
197 struct mmiotrace_rw *my_trace = &get_cpu_var(cpu_trace);
198
199 /* this should always return the active_trace count to 0 */
200 my_reason->active_traces--;
201 if (my_reason->active_traces) {
202 pr_emerg("unexpected post handler");
203 BUG();
204 }
205
206 switch (my_reason->type) {
207 case REG_READ:
208 my_trace->value = get_ins_reg_val(my_reason->ip, regs);
209 break;
210 default:
211 break;
212 }
213
214 mmio_trace_rw(my_trace);
215 put_cpu_var(cpu_trace);
216 put_cpu_var(pf_reason);
217}
218
219static void ioremap_trace_core(resource_size_t offset, unsigned long size,
220 void __iomem *addr)
221{
222 static atomic_t next_id;
223 struct remap_trace *trace = kmalloc(sizeof(*trace), GFP_KERNEL);
224 /* These are page-unaligned. */
225 struct mmiotrace_map map = {
226 .phys = offset,
227 .virt = (unsigned long)addr,
228 .len = size,
229 .opcode = MMIO_PROBE
230 };
231
232 if (!trace) {
233 pr_err("kmalloc failed in ioremap\n");
234 return;
235 }
236
237 *trace = (struct remap_trace) {
238 .probe = {
239 .addr = (unsigned long)addr,
240 .len = size,
241 .pre_handler = pre,
242 .post_handler = post,
243 .private = trace
244 },
245 .phys = offset,
246 .id = atomic_inc_return(&next_id)
247 };
248 map.map_id = trace->id;
249
250 spin_lock_irq(&trace_lock);
251 if (!is_enabled()) {
252 kfree(trace);
253 goto not_enabled;
254 }
255
256 mmio_trace_mapping(&map);
257 list_add_tail(&trace->list, &trace_list);
258 if (!nommiotrace)
259 register_kmmio_probe(&trace->probe);
260
261not_enabled:
262 spin_unlock_irq(&trace_lock);
263}
264
265void mmiotrace_ioremap(resource_size_t offset, unsigned long size,
266 void __iomem *addr)
267{
268 if (!is_enabled()) /* recheck and proper locking in *_core() */
269 return;
270
271 pr_debug("ioremap_*(0x%llx, 0x%lx) = %p\n",
272 (unsigned long long)offset, size, addr);
273 if ((filter_offset) && (offset != filter_offset))
274 return;
275 ioremap_trace_core(offset, size, addr);
276}
277
278static void iounmap_trace_core(volatile void __iomem *addr)
279{
280 struct mmiotrace_map map = {
281 .phys = 0,
282 .virt = (unsigned long)addr,
283 .len = 0,
284 .opcode = MMIO_UNPROBE
285 };
286 struct remap_trace *trace;
287 struct remap_trace *tmp;
288 struct remap_trace *found_trace = NULL;
289
290 pr_debug("Unmapping %p.\n", addr);
291
292 spin_lock_irq(&trace_lock);
293 if (!is_enabled())
294 goto not_enabled;
295
296 list_for_each_entry_safe(trace, tmp, &trace_list, list) {
297 if ((unsigned long)addr == trace->probe.addr) {
298 if (!nommiotrace)
299 unregister_kmmio_probe(&trace->probe);
300 list_del(&trace->list);
301 found_trace = trace;
302 break;
303 }
304 }
305 map.map_id = (found_trace) ? found_trace->id : -1;
306 mmio_trace_mapping(&map);
307
308not_enabled:
309 spin_unlock_irq(&trace_lock);
310 if (found_trace) {
311 synchronize_rcu(); /* unregister_kmmio_probe() requirement */
312 kfree(found_trace);
313 }
314}
315
316void mmiotrace_iounmap(volatile void __iomem *addr)
317{
318 might_sleep();
319 if (is_enabled()) /* recheck and proper locking in *_core() */
320 iounmap_trace_core(addr);
321}
322
323int mmiotrace_printk(const char *fmt, ...)
324{
325 int ret = 0;
326 va_list args;
327 unsigned long flags;
328 va_start(args, fmt);
329
330 spin_lock_irqsave(&trace_lock, flags);
331 if (is_enabled())
332 ret = mmio_trace_printk(fmt, args);
333 spin_unlock_irqrestore(&trace_lock, flags);
334
335 va_end(args);
336 return ret;
337}
338EXPORT_SYMBOL(mmiotrace_printk);
339
340static void clear_trace_list(void)
341{
342 struct remap_trace *trace;
343 struct remap_trace *tmp;
344
345 /*
346 * No locking required, because the caller ensures we are in a
347 * critical section via mutex, and is_enabled() is false,
348 * i.e. nothing can traverse or modify this list.
349 * Caller also ensures is_enabled() cannot change.
350 */
351 list_for_each_entry(trace, &trace_list, list) {
352 pr_notice("purging non-iounmapped trace @0x%08lx, size 0x%lx.\n",
353 trace->probe.addr, trace->probe.len);
354 if (!nommiotrace)
355 unregister_kmmio_probe(&trace->probe);
356 }
357 synchronize_rcu(); /* unregister_kmmio_probe() requirement */
358
359 list_for_each_entry_safe(trace, tmp, &trace_list, list) {
360 list_del(&trace->list);
361 kfree(trace);
362 }
363}
364
365#ifdef CONFIG_HOTPLUG_CPU
366static cpumask_var_t downed_cpus;
367
368static void enter_uniprocessor(void)
369{
370 int cpu;
371 int err;
372
373 if (!cpumask_available(downed_cpus) &&
374 !alloc_cpumask_var(&downed_cpus, GFP_KERNEL)) {
375 pr_notice("Failed to allocate mask\n");
376 goto out;
377 }
378
379 cpus_read_lock();
380 cpumask_copy(downed_cpus, cpu_online_mask);
381 cpumask_clear_cpu(cpumask_first(cpu_online_mask), downed_cpus);
382 if (num_online_cpus() > 1)
383 pr_notice("Disabling non-boot CPUs...\n");
384 cpus_read_unlock();
385
386 for_each_cpu(cpu, downed_cpus) {
387 err = remove_cpu(cpu);
388 if (!err)
389 pr_info("CPU%d is down.\n", cpu);
390 else
391 pr_err("Error taking CPU%d down: %d\n", cpu, err);
392 }
393out:
394 if (num_online_cpus() > 1)
395 pr_warn("multiple CPUs still online, may miss events.\n");
396}
397
398static void leave_uniprocessor(void)
399{
400 int cpu;
401 int err;
402
403 if (!cpumask_available(downed_cpus) || cpumask_empty(downed_cpus))
404 return;
405 pr_notice("Re-enabling CPUs...\n");
406 for_each_cpu(cpu, downed_cpus) {
407 err = add_cpu(cpu);
408 if (!err)
409 pr_info("enabled CPU%d.\n", cpu);
410 else
411 pr_err("cannot re-enable CPU%d: %d\n", cpu, err);
412 }
413}
414
415#else /* !CONFIG_HOTPLUG_CPU */
416static void enter_uniprocessor(void)
417{
418 if (num_online_cpus() > 1)
419 pr_warn("multiple CPUs are online, may miss events. "
420 "Suggest booting with maxcpus=1 kernel argument.\n");
421}
422
423static void leave_uniprocessor(void)
424{
425}
426#endif
427
428void enable_mmiotrace(void)
429{
430 mutex_lock(&mmiotrace_mutex);
431 if (is_enabled())
432 goto out;
433
434 if (nommiotrace)
435 pr_info("MMIO tracing disabled.\n");
436 kmmio_init();
437 enter_uniprocessor();
438 spin_lock_irq(&trace_lock);
439 atomic_inc(&mmiotrace_enabled);
440 spin_unlock_irq(&trace_lock);
441 pr_info("enabled.\n");
442out:
443 mutex_unlock(&mmiotrace_mutex);
444}
445
446void disable_mmiotrace(void)
447{
448 mutex_lock(&mmiotrace_mutex);
449 if (!is_enabled())
450 goto out;
451
452 spin_lock_irq(&trace_lock);
453 atomic_dec(&mmiotrace_enabled);
454 BUG_ON(is_enabled());
455 spin_unlock_irq(&trace_lock);
456
457 clear_trace_list(); /* guarantees: no more kmmio callbacks */
458 leave_uniprocessor();
459 kmmio_cleanup();
460 pr_info("disabled.\n");
461out:
462 mutex_unlock(&mmiotrace_mutex);
463}
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}