include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit...
[linux-3.10.git] / arch / x86 / mm / mmio-mod.c
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 <asm/atomic.h>
38 #include <linux/percpu.h>
39 #include <linux/cpu.h>
40
41 #include "pf_in.h"
42
43 struct trap_reason {
44         unsigned long addr;
45         unsigned long ip;
46         enum reason_type type;
47         int active_traces;
48 };
49
50 struct 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. */
58 static DEFINE_PER_CPU(struct trap_reason, pf_reason);
59 static DEFINE_PER_CPU(struct mmiotrace_rw, cpu_trace);
60
61 static DEFINE_MUTEX(mmiotrace_mutex);
62 static DEFINE_SPINLOCK(trace_lock);
63 static atomic_t mmiotrace_enabled;
64 static LIST_HEAD(trace_list);           /* struct remap_trace */
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 */
78 static unsigned long    filter_offset;
79 static int              nommiotrace;
80 static int              trace_pc;
81
82 module_param(filter_offset, ulong, 0);
83 module_param(nommiotrace, bool, 0);
84 module_param(trace_pc, bool, 0);
85
86 MODULE_PARM_DESC(filter_offset, "Start address of traced mappings.");
87 MODULE_PARM_DESC(nommiotrace, "Disable actual MMIO tracing.");
88 MODULE_PARM_DESC(trace_pc, "Record address of faulting instructions.");
89
90 static bool is_enabled(void)
91 {
92         return atomic_read(&mmiotrace_enabled);
93 }
94
95 static 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  */
121 static 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
144 static 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
209 static 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
235 static 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
277 not_enabled:
278         spin_unlock_irq(&trace_lock);
279 }
280
281 void 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
294 static 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
324 not_enabled:
325         spin_unlock_irq(&trace_lock);
326         if (found_trace) {
327                 synchronize_rcu(); /* unregister_kmmio_probe() requirement */
328                 kfree(found_trace);
329         }
330 }
331
332 void mmiotrace_iounmap(volatile void __iomem *addr)
333 {
334         might_sleep();
335         if (is_enabled()) /* recheck and proper locking in *_core() */
336                 iounmap_trace_core(addr);
337 }
338
339 int mmiotrace_printk(const char *fmt, ...)
340 {
341         int ret = 0;
342         va_list args;
343         unsigned long flags;
344         va_start(args, fmt);
345
346         spin_lock_irqsave(&trace_lock, flags);
347         if (is_enabled())
348                 ret = mmio_trace_printk(fmt, args);
349         spin_unlock_irqrestore(&trace_lock, flags);
350
351         va_end(args);
352         return ret;
353 }
354 EXPORT_SYMBOL(mmiotrace_printk);
355
356 static 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
382 static cpumask_var_t downed_cpus;
383
384 static 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         }
409 out:
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 */
416 static 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 */
434 static 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
441 static void leave_uniprocessor(void)
442 {
443 }
444 #endif
445
446 void 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");
460 out:
461         mutex_unlock(&mmiotrace_mutex);
462 }
463
464 void 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");
479 out:
480         mutex_unlock(&mmiotrace_mutex);
481 }