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.
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.
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.
16 * Copyright (C) IBM Corporation, 2005
17 * Jeff Muizelaar, 2006, 2007
18 * Pekka Paalanen, 2008 <pq@iki.fi>
20 * Derived from the read-mod example from relay-examples by Tom Zanussi.
22 #include <linux/module.h>
23 #include <linux/relay.h>
24 #include <linux/debugfs.h>
25 #include <linux/proc_fs.h>
27 #include <linux/version.h>
28 #include <linux/kallsyms.h>
29 #include <asm/pgtable.h>
30 #include <linux/mmiotrace.h>
31 #include <asm/e820.h> /* for ISA_START_ADDRESS */
36 /* This app's relay channel files will appear in /debug/mmio-trace */
37 #define APP_DIR "mmio-trace"
38 /* the marker injection file in /proc */
39 #define MARKER_FILE "mmio-marker"
41 #define MODULE_NAME "mmiotrace"
46 enum reason_type type;
50 static struct trap_reason pf_reason[NR_CPUS];
51 static struct mm_io_header_rw cpu_trace[NR_CPUS];
53 static struct file_operations mmio_fops = {
57 static const size_t subbuf_size = 256*1024;
58 static struct rchan *chan;
59 static struct dentry *dir;
60 static int suspended; /* XXX should this be per cpu? */
61 static struct proc_dir_entry *proc_marker_file;
63 /* module parameters */
64 static unsigned int n_subbufs = 32*4;
65 static unsigned long filter_offset;
66 static int nommiotrace;
70 module_param(n_subbufs, uint, 0);
71 module_param(filter_offset, ulong, 0);
72 module_param(nommiotrace, bool, 0);
73 module_param(ISA_trace, bool, 0);
74 module_param(trace_pc, bool, 0);
76 MODULE_PARM_DESC(n_subbufs, "Number of 256kB buffers, default 128.");
77 MODULE_PARM_DESC(filter_offset, "Start address of traced mappings.");
78 MODULE_PARM_DESC(nommiotrace, "Disable actual MMIO tracing.");
79 MODULE_PARM_DESC(ISA_trace, "Do not exclude the low ISA range.");
80 MODULE_PARM_DESC(trace_pc, "Record address of faulting instructions.");
82 static void record_timestamp(struct mm_io_header *header)
87 header->sec = now.tv_sec;
88 header->nsec = now.tv_nsec;
92 * Write callback for the /proc entry:
93 * Read a marker and write it to the mmio trace log
95 static int write_marker(struct file *file, const char __user *buffer,
96 unsigned long count, void *data)
99 struct mm_io_header *headp;
100 int len = (count > 65535) ? 65535 : count;
102 event = kzalloc(sizeof(*headp) + len, GFP_KERNEL);
106 headp = (struct mm_io_header *)event;
107 headp->type = MMIO_MAGIC | (MMIO_MARKER << MMIO_OPCODE_SHIFT);
108 headp->data_len = len;
109 record_timestamp(headp);
111 if (copy_from_user(event + sizeof(*headp), buffer, len)) {
116 relay_write(chan, event, sizeof(*headp) + len);
121 static void print_pte(unsigned long address)
124 pte_t *pte = lookup_address(address, &level);
127 printk(KERN_ERR "Error in %s: no pte for page 0x%08lx\n",
128 __FUNCTION__, address);
132 if (level == PG_LEVEL_2M) {
133 printk(KERN_EMERG MODULE_NAME ": 4MB pages are not "
134 "currently supported: %lx\n",
138 printk(KERN_DEBUG MODULE_NAME ": pte for 0x%lx: 0x%lx 0x%lx\n",
139 address, pte_val(*pte),
140 pte_val(*pte) & _PAGE_PRESENT);
144 * For some reason the pre/post pairs have been called in an
145 * unmatched order. Report and die.
147 static void die_kmmio_nesting_error(struct pt_regs *regs, unsigned long addr)
149 const unsigned long cpu = smp_processor_id();
150 printk(KERN_EMERG MODULE_NAME ": unexpected fault for address: %lx, "
151 "last fault for address: %lx\n",
152 addr, pf_reason[cpu].addr);
155 print_symbol(KERN_EMERG "faulting EIP is at %s\n", regs->ip);
156 print_symbol(KERN_EMERG "last faulting EIP was at %s\n",
159 "eax: %08lx ebx: %08lx ecx: %08lx edx: %08lx\n",
160 regs->ax, regs->bx, regs->cx, regs->dx);
162 "esi: %08lx edi: %08lx ebp: %08lx esp: %08lx\n",
163 regs->si, regs->di, regs->bp, regs->sp);
165 print_symbol(KERN_EMERG "faulting RIP is at %s\n", regs->ip);
166 print_symbol(KERN_EMERG "last faulting RIP was at %s\n",
168 printk(KERN_EMERG "rax: %016lx rcx: %016lx rdx: %016lx\n",
169 regs->ax, regs->cx, regs->dx);
170 printk(KERN_EMERG "rsi: %016lx rdi: %016lx "
171 "rbp: %016lx rsp: %016lx\n",
172 regs->si, regs->di, regs->bp, regs->sp);
177 static void pre(struct kmmio_probe *p, struct pt_regs *regs,
180 const unsigned long cpu = smp_processor_id();
181 const unsigned long instptr = instruction_pointer(regs);
182 const enum reason_type type = get_ins_type(instptr);
184 /* it doesn't make sense to have more than one active trace per cpu */
185 if (pf_reason[cpu].active_traces)
186 die_kmmio_nesting_error(regs, addr);
188 pf_reason[cpu].active_traces++;
190 pf_reason[cpu].type = type;
191 pf_reason[cpu].addr = addr;
192 pf_reason[cpu].ip = instptr;
194 cpu_trace[cpu].header.type = MMIO_MAGIC;
195 cpu_trace[cpu].header.pid = 0;
196 cpu_trace[cpu].header.data_len = sizeof(struct mm_io_rw);
197 cpu_trace[cpu].rw.address = addr;
200 * Only record the program counter when requested.
201 * It may taint clean-room reverse engineering.
204 cpu_trace[cpu].rw.pc = instptr;
206 cpu_trace[cpu].rw.pc = 0;
208 record_timestamp(&cpu_trace[cpu].header);
212 cpu_trace[cpu].header.type |=
213 (MMIO_READ << MMIO_OPCODE_SHIFT) |
214 (get_ins_mem_width(instptr) << MMIO_WIDTH_SHIFT);
217 cpu_trace[cpu].header.type |=
218 (MMIO_WRITE << MMIO_OPCODE_SHIFT) |
219 (get_ins_mem_width(instptr) << MMIO_WIDTH_SHIFT);
220 cpu_trace[cpu].rw.value = get_ins_reg_val(instptr, regs);
223 cpu_trace[cpu].header.type |=
224 (MMIO_WRITE << MMIO_OPCODE_SHIFT) |
225 (get_ins_mem_width(instptr) << MMIO_WIDTH_SHIFT);
226 cpu_trace[cpu].rw.value = get_ins_imm_val(instptr);
230 unsigned char *ip = (unsigned char *)instptr;
231 cpu_trace[cpu].header.type |=
232 (MMIO_UNKNOWN_OP << MMIO_OPCODE_SHIFT);
233 cpu_trace[cpu].rw.value = (*ip) << 16 |
240 static void post(struct kmmio_probe *p, unsigned long condition,
241 struct pt_regs *regs)
243 const unsigned long cpu = smp_processor_id();
245 /* this should always return the active_trace count to 0 */
246 pf_reason[cpu].active_traces--;
247 if (pf_reason[cpu].active_traces) {
248 printk(KERN_EMERG MODULE_NAME ": unexpected post handler");
252 switch (pf_reason[cpu].type) {
254 cpu_trace[cpu].rw.value = get_ins_reg_val(pf_reason[cpu].ip,
260 relay_write(chan, &cpu_trace[cpu], sizeof(struct mm_io_header_rw));
264 * subbuf_start() relay callback.
266 * Defined so that we know when events are dropped due to the buffer-full
269 static int subbuf_start_handler(struct rchan_buf *buf, void *subbuf,
270 void *prev_subbuf, size_t prev_padding)
272 if (relay_buf_full(buf)) {
275 printk(KERN_ERR MODULE_NAME
276 ": cpu %d buffer full!!!\n",
280 } else if (suspended) {
282 printk(KERN_ERR MODULE_NAME
283 ": cpu %d buffer no longer full.\n",
290 /* file_create() callback. Creates relay file in debugfs. */
291 static struct dentry *create_buf_file_handler(const char *filename,
292 struct dentry *parent,
294 struct rchan_buf *buf,
297 struct dentry *buf_file;
299 mmio_fops.read = relay_file_operations.read;
300 mmio_fops.open = relay_file_operations.open;
301 mmio_fops.poll = relay_file_operations.poll;
302 mmio_fops.mmap = relay_file_operations.mmap;
303 mmio_fops.release = relay_file_operations.release;
304 mmio_fops.splice_read = relay_file_operations.splice_read;
306 buf_file = debugfs_create_file(filename, mode, parent, buf,
312 /* file_remove() default callback. Removes relay file in debugfs. */
313 static int remove_buf_file_handler(struct dentry *dentry)
315 debugfs_remove(dentry);
319 static struct rchan_callbacks relay_callbacks = {
320 .subbuf_start = subbuf_start_handler,
321 .create_buf_file = create_buf_file_handler,
322 .remove_buf_file = remove_buf_file_handler,
326 * create_channel - creates channel /debug/APP_DIR/cpuXXX
327 * Returns channel on success, NULL otherwise
329 static struct rchan *create_channel(unsigned size, unsigned n)
331 return relay_open("cpu", dir, size, n, &relay_callbacks, NULL);
334 /* destroy_channel - destroys channel /debug/APP_DIR/cpuXXX */
335 static void destroy_channel(void)
344 struct list_head list;
345 struct kmmio_probe probe;
347 static LIST_HEAD(trace_list);
348 static DEFINE_SPINLOCK(trace_list_lock);
350 static void do_ioremap_trace_core(unsigned long offset, unsigned long size,
353 struct remap_trace *trace = kmalloc(sizeof(*trace), GFP_KERNEL);
354 struct mm_io_header_map event = {
357 (MMIO_PROBE << MMIO_OPCODE_SHIFT),
361 .data_len = sizeof(struct mm_io_map)
365 .addr = (unsigned long)addr,
370 record_timestamp(&event.header);
372 *trace = (struct remap_trace) {
374 .addr = (unsigned long)addr,
377 .post_handler = post,
381 relay_write(chan, &event, sizeof(event));
382 spin_lock(&trace_list_lock);
383 list_add_tail(&trace->list, &trace_list);
384 spin_unlock(&trace_list_lock);
386 register_kmmio_probe(&trace->probe);
389 static void ioremap_trace_core(unsigned long offset, unsigned long size,
392 if ((filter_offset) && (offset != filter_offset))
395 /* Don't trace the low PCI/ISA area, it's always mapped.. */
396 if (!ISA_trace && (offset < ISA_END_ADDRESS) &&
397 (offset + size > ISA_START_ADDRESS)) {
398 printk(KERN_NOTICE MODULE_NAME ": Ignoring map of low "
399 "PCI/ISA area (0x%lx-0x%lx)\n",
400 offset, offset + size);
403 do_ioremap_trace_core(offset, size, addr);
406 void __iomem *ioremap_cache_trace(unsigned long offset, unsigned long size)
408 void __iomem *p = ioremap_cache(offset, size);
409 printk(KERN_DEBUG MODULE_NAME ": ioremap_cache(0x%lx, 0x%lx) = %p\n",
411 ioremap_trace_core(offset, size, p);
414 EXPORT_SYMBOL(ioremap_cache_trace);
416 void __iomem *ioremap_nocache_trace(unsigned long offset, unsigned long size)
418 void __iomem *p = ioremap_nocache(offset, size);
419 printk(KERN_DEBUG MODULE_NAME ": ioremap_nocache(0x%lx, 0x%lx) = %p\n",
421 ioremap_trace_core(offset, size, p);
424 EXPORT_SYMBOL(ioremap_nocache_trace);
426 void iounmap_trace(volatile void __iomem *addr)
428 struct mm_io_header_map event = {
431 (MMIO_UNPROBE << MMIO_OPCODE_SHIFT),
435 .data_len = sizeof(struct mm_io_map)
439 .addr = (unsigned long)addr,
444 struct remap_trace *trace;
445 struct remap_trace *tmp;
446 printk(KERN_DEBUG MODULE_NAME ": Unmapping %p.\n", addr);
447 record_timestamp(&event.header);
449 spin_lock(&trace_list_lock);
450 list_for_each_entry_safe(trace, tmp, &trace_list, list) {
451 if ((unsigned long)addr == trace->probe.addr) {
453 unregister_kmmio_probe(&trace->probe);
454 list_del(&trace->list);
459 spin_unlock(&trace_list_lock);
460 relay_write(chan, &event, sizeof(event));
463 EXPORT_SYMBOL(iounmap_trace);
465 static void clear_trace_list(void)
467 struct remap_trace *trace;
468 struct remap_trace *tmp;
470 spin_lock(&trace_list_lock);
471 list_for_each_entry_safe(trace, tmp, &trace_list, list) {
472 printk(KERN_WARNING MODULE_NAME ": purging non-iounmapped "
473 "trace @0x%08lx, size 0x%lx.\n",
474 trace->probe.addr, trace->probe.len);
476 unregister_kmmio_probe(&trace->probe);
477 list_del(&trace->list);
481 spin_unlock(&trace_list_lock);
484 static int __init init(void)
489 dir = debugfs_create_dir(APP_DIR, NULL);
491 printk(KERN_ERR MODULE_NAME
492 ": Couldn't create relay app directory.\n");
496 chan = create_channel(subbuf_size, n_subbufs);
499 printk(KERN_ERR MODULE_NAME
500 ": relay app channel creation failed\n");
506 proc_marker_file = create_proc_entry(MARKER_FILE, 0, NULL);
507 if (proc_marker_file)
508 proc_marker_file->write_proc = write_marker;
510 printk(KERN_DEBUG MODULE_NAME ": loaded.\n");
512 printk(KERN_DEBUG MODULE_NAME ": MMIO tracing disabled.\n");
514 printk(KERN_WARNING MODULE_NAME
515 ": Warning! low ISA range will be traced.\n");
519 static void __exit cleanup(void)
521 printk(KERN_DEBUG MODULE_NAME ": unload...\n");
524 remove_proc_entry(MARKER_FILE, NULL);
531 module_exit(cleanup);
532 MODULE_LICENSE("GPL");