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