iwlwifi: mvm: fix version check for GEO_TX_POWER_LIMIT support
[linux/fpc-iii.git] / arch / sh / kernel / kprobes.c
blob241e903dd3ee224a7f05b2318854389afeb13a94
1 /*
2 * Kernel probes (kprobes) for SuperH
4 * Copyright (C) 2007 Chris Smith <chris.smith@st.com>
5 * Copyright (C) 2006 Lineo Solutions, Inc.
7 * This file is subject to the terms and conditions of the GNU General Public
8 * License. See the file "COPYING" in the main directory of this archive
9 * for more details.
11 #include <linux/kprobes.h>
12 #include <linux/extable.h>
13 #include <linux/ptrace.h>
14 #include <linux/preempt.h>
15 #include <linux/kdebug.h>
16 #include <linux/slab.h>
17 #include <asm/cacheflush.h>
18 #include <linux/uaccess.h>
20 DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
21 DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
23 static DEFINE_PER_CPU(struct kprobe, saved_current_opcode);
24 static DEFINE_PER_CPU(struct kprobe, saved_next_opcode);
25 static DEFINE_PER_CPU(struct kprobe, saved_next_opcode2);
27 #define OPCODE_JMP(x) (((x) & 0xF0FF) == 0x402b)
28 #define OPCODE_JSR(x) (((x) & 0xF0FF) == 0x400b)
29 #define OPCODE_BRA(x) (((x) & 0xF000) == 0xa000)
30 #define OPCODE_BRAF(x) (((x) & 0xF0FF) == 0x0023)
31 #define OPCODE_BSR(x) (((x) & 0xF000) == 0xb000)
32 #define OPCODE_BSRF(x) (((x) & 0xF0FF) == 0x0003)
34 #define OPCODE_BF_S(x) (((x) & 0xFF00) == 0x8f00)
35 #define OPCODE_BT_S(x) (((x) & 0xFF00) == 0x8d00)
37 #define OPCODE_BF(x) (((x) & 0xFF00) == 0x8b00)
38 #define OPCODE_BT(x) (((x) & 0xFF00) == 0x8900)
40 #define OPCODE_RTS(x) (((x) & 0x000F) == 0x000b)
41 #define OPCODE_RTE(x) (((x) & 0xFFFF) == 0x002b)
43 int __kprobes arch_prepare_kprobe(struct kprobe *p)
45 kprobe_opcode_t opcode = *(kprobe_opcode_t *) (p->addr);
47 if (OPCODE_RTE(opcode))
48 return -EFAULT; /* Bad breakpoint */
50 p->opcode = opcode;
52 return 0;
55 void __kprobes arch_copy_kprobe(struct kprobe *p)
57 memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
58 p->opcode = *p->addr;
61 void __kprobes arch_arm_kprobe(struct kprobe *p)
63 *p->addr = BREAKPOINT_INSTRUCTION;
64 flush_icache_range((unsigned long)p->addr,
65 (unsigned long)p->addr + sizeof(kprobe_opcode_t));
68 void __kprobes arch_disarm_kprobe(struct kprobe *p)
70 *p->addr = p->opcode;
71 flush_icache_range((unsigned long)p->addr,
72 (unsigned long)p->addr + sizeof(kprobe_opcode_t));
75 int __kprobes arch_trampoline_kprobe(struct kprobe *p)
77 if (*p->addr == BREAKPOINT_INSTRUCTION)
78 return 1;
80 return 0;
83 /**
84 * If an illegal slot instruction exception occurs for an address
85 * containing a kprobe, remove the probe.
87 * Returns 0 if the exception was handled successfully, 1 otherwise.
89 int __kprobes kprobe_handle_illslot(unsigned long pc)
91 struct kprobe *p = get_kprobe((kprobe_opcode_t *) pc + 1);
93 if (p != NULL) {
94 printk("Warning: removing kprobe from delay slot: 0x%.8x\n",
95 (unsigned int)pc + 2);
96 unregister_kprobe(p);
97 return 0;
100 return 1;
103 void __kprobes arch_remove_kprobe(struct kprobe *p)
105 struct kprobe *saved = this_cpu_ptr(&saved_next_opcode);
107 if (saved->addr) {
108 arch_disarm_kprobe(p);
109 arch_disarm_kprobe(saved);
111 saved->addr = NULL;
112 saved->opcode = 0;
114 saved = this_cpu_ptr(&saved_next_opcode2);
115 if (saved->addr) {
116 arch_disarm_kprobe(saved);
118 saved->addr = NULL;
119 saved->opcode = 0;
124 static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
126 kcb->prev_kprobe.kp = kprobe_running();
127 kcb->prev_kprobe.status = kcb->kprobe_status;
130 static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
132 __this_cpu_write(current_kprobe, kcb->prev_kprobe.kp);
133 kcb->kprobe_status = kcb->prev_kprobe.status;
136 static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
137 struct kprobe_ctlblk *kcb)
139 __this_cpu_write(current_kprobe, p);
143 * Singlestep is implemented by disabling the current kprobe and setting one
144 * on the next instruction, following branches. Two probes are set if the
145 * branch is conditional.
147 static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
149 __this_cpu_write(saved_current_opcode.addr, (kprobe_opcode_t *)regs->pc);
151 if (p != NULL) {
152 struct kprobe *op1, *op2;
154 arch_disarm_kprobe(p);
156 op1 = this_cpu_ptr(&saved_next_opcode);
157 op2 = this_cpu_ptr(&saved_next_opcode2);
159 if (OPCODE_JSR(p->opcode) || OPCODE_JMP(p->opcode)) {
160 unsigned int reg_nr = ((p->opcode >> 8) & 0x000F);
161 op1->addr = (kprobe_opcode_t *) regs->regs[reg_nr];
162 } else if (OPCODE_BRA(p->opcode) || OPCODE_BSR(p->opcode)) {
163 unsigned long disp = (p->opcode & 0x0FFF);
164 op1->addr =
165 (kprobe_opcode_t *) (regs->pc + 4 + disp * 2);
167 } else if (OPCODE_BRAF(p->opcode) || OPCODE_BSRF(p->opcode)) {
168 unsigned int reg_nr = ((p->opcode >> 8) & 0x000F);
169 op1->addr =
170 (kprobe_opcode_t *) (regs->pc + 4 +
171 regs->regs[reg_nr]);
173 } else if (OPCODE_RTS(p->opcode)) {
174 op1->addr = (kprobe_opcode_t *) regs->pr;
176 } else if (OPCODE_BF(p->opcode) || OPCODE_BT(p->opcode)) {
177 unsigned long disp = (p->opcode & 0x00FF);
178 /* case 1 */
179 op1->addr = p->addr + 1;
180 /* case 2 */
181 op2->addr =
182 (kprobe_opcode_t *) (regs->pc + 4 + disp * 2);
183 op2->opcode = *(op2->addr);
184 arch_arm_kprobe(op2);
186 } else if (OPCODE_BF_S(p->opcode) || OPCODE_BT_S(p->opcode)) {
187 unsigned long disp = (p->opcode & 0x00FF);
188 /* case 1 */
189 op1->addr = p->addr + 2;
190 /* case 2 */
191 op2->addr =
192 (kprobe_opcode_t *) (regs->pc + 4 + disp * 2);
193 op2->opcode = *(op2->addr);
194 arch_arm_kprobe(op2);
196 } else {
197 op1->addr = p->addr + 1;
200 op1->opcode = *(op1->addr);
201 arch_arm_kprobe(op1);
205 /* Called with kretprobe_lock held */
206 void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
207 struct pt_regs *regs)
209 ri->ret_addr = (kprobe_opcode_t *) regs->pr;
211 /* Replace the return addr with trampoline addr */
212 regs->pr = (unsigned long)kretprobe_trampoline;
215 static int __kprobes kprobe_handler(struct pt_regs *regs)
217 struct kprobe *p;
218 int ret = 0;
219 kprobe_opcode_t *addr = NULL;
220 struct kprobe_ctlblk *kcb;
223 * We don't want to be preempted for the entire
224 * duration of kprobe processing
226 preempt_disable();
227 kcb = get_kprobe_ctlblk();
229 addr = (kprobe_opcode_t *) (regs->pc);
231 /* Check we're not actually recursing */
232 if (kprobe_running()) {
233 p = get_kprobe(addr);
234 if (p) {
235 if (kcb->kprobe_status == KPROBE_HIT_SS &&
236 *p->ainsn.insn == BREAKPOINT_INSTRUCTION) {
237 goto no_kprobe;
239 /* We have reentered the kprobe_handler(), since
240 * another probe was hit while within the handler.
241 * We here save the original kprobes variables and
242 * just single step on the instruction of the new probe
243 * without calling any user handlers.
245 save_previous_kprobe(kcb);
246 set_current_kprobe(p, regs, kcb);
247 kprobes_inc_nmissed_count(p);
248 prepare_singlestep(p, regs);
249 kcb->kprobe_status = KPROBE_REENTER;
250 return 1;
252 goto no_kprobe;
255 p = get_kprobe(addr);
256 if (!p) {
257 /* Not one of ours: let kernel handle it */
258 if (*(kprobe_opcode_t *)addr != BREAKPOINT_INSTRUCTION) {
260 * The breakpoint instruction was removed right
261 * after we hit it. Another cpu has removed
262 * either a probepoint or a debugger breakpoint
263 * at this address. In either case, no further
264 * handling of this interrupt is appropriate.
266 ret = 1;
269 goto no_kprobe;
272 set_current_kprobe(p, regs, kcb);
273 kcb->kprobe_status = KPROBE_HIT_ACTIVE;
275 if (p->pre_handler && p->pre_handler(p, regs)) {
276 /* handler has already set things up, so skip ss setup */
277 reset_current_kprobe();
278 preempt_enable_no_resched();
279 return 1;
282 prepare_singlestep(p, regs);
283 kcb->kprobe_status = KPROBE_HIT_SS;
284 return 1;
286 no_kprobe:
287 preempt_enable_no_resched();
288 return ret;
292 * For function-return probes, init_kprobes() establishes a probepoint
293 * here. When a retprobed function returns, this probe is hit and
294 * trampoline_probe_handler() runs, calling the kretprobe's handler.
296 static void __used kretprobe_trampoline_holder(void)
298 asm volatile (".globl kretprobe_trampoline\n"
299 "kretprobe_trampoline:\n\t"
300 "nop\n");
304 * Called when we hit the probe point at kretprobe_trampoline
306 int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
308 struct kretprobe_instance *ri = NULL;
309 struct hlist_head *head, empty_rp;
310 struct hlist_node *tmp;
311 unsigned long flags, orig_ret_address = 0;
312 unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline;
314 INIT_HLIST_HEAD(&empty_rp);
315 kretprobe_hash_lock(current, &head, &flags);
318 * It is possible to have multiple instances associated with a given
319 * task either because an multiple functions in the call path
320 * have a return probe installed on them, and/or more then one return
321 * return probe was registered for a target function.
323 * We can handle this because:
324 * - instances are always inserted at the head of the list
325 * - when multiple return probes are registered for the same
326 * function, the first instance's ret_addr will point to the
327 * real return address, and all the rest will point to
328 * kretprobe_trampoline
330 hlist_for_each_entry_safe(ri, tmp, head, hlist) {
331 if (ri->task != current)
332 /* another task is sharing our hash bucket */
333 continue;
335 if (ri->rp && ri->rp->handler) {
336 __this_cpu_write(current_kprobe, &ri->rp->kp);
337 ri->rp->handler(ri, regs);
338 __this_cpu_write(current_kprobe, NULL);
341 orig_ret_address = (unsigned long)ri->ret_addr;
342 recycle_rp_inst(ri, &empty_rp);
344 if (orig_ret_address != trampoline_address)
346 * This is the real return address. Any other
347 * instances associated with this task are for
348 * other calls deeper on the call stack
350 break;
353 kretprobe_assert(ri, orig_ret_address, trampoline_address);
355 regs->pc = orig_ret_address;
356 kretprobe_hash_unlock(current, &flags);
358 hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
359 hlist_del(&ri->hlist);
360 kfree(ri);
363 return orig_ret_address;
366 static int __kprobes post_kprobe_handler(struct pt_regs *regs)
368 struct kprobe *cur = kprobe_running();
369 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
370 kprobe_opcode_t *addr = NULL;
371 struct kprobe *p = NULL;
373 if (!cur)
374 return 0;
376 if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
377 kcb->kprobe_status = KPROBE_HIT_SSDONE;
378 cur->post_handler(cur, regs, 0);
381 p = this_cpu_ptr(&saved_next_opcode);
382 if (p->addr) {
383 arch_disarm_kprobe(p);
384 p->addr = NULL;
385 p->opcode = 0;
387 addr = __this_cpu_read(saved_current_opcode.addr);
388 __this_cpu_write(saved_current_opcode.addr, NULL);
390 p = get_kprobe(addr);
391 arch_arm_kprobe(p);
393 p = this_cpu_ptr(&saved_next_opcode2);
394 if (p->addr) {
395 arch_disarm_kprobe(p);
396 p->addr = NULL;
397 p->opcode = 0;
401 /* Restore back the original saved kprobes variables and continue. */
402 if (kcb->kprobe_status == KPROBE_REENTER) {
403 restore_previous_kprobe(kcb);
404 goto out;
407 reset_current_kprobe();
409 out:
410 preempt_enable_no_resched();
412 return 1;
415 int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
417 struct kprobe *cur = kprobe_running();
418 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
419 const struct exception_table_entry *entry;
421 switch (kcb->kprobe_status) {
422 case KPROBE_HIT_SS:
423 case KPROBE_REENTER:
425 * We are here because the instruction being single
426 * stepped caused a page fault. We reset the current
427 * kprobe, point the pc back to the probe address
428 * and allow the page fault handler to continue as a
429 * normal page fault.
431 regs->pc = (unsigned long)cur->addr;
432 if (kcb->kprobe_status == KPROBE_REENTER)
433 restore_previous_kprobe(kcb);
434 else
435 reset_current_kprobe();
436 preempt_enable_no_resched();
437 break;
438 case KPROBE_HIT_ACTIVE:
439 case KPROBE_HIT_SSDONE:
441 * We increment the nmissed count for accounting,
442 * we can also use npre/npostfault count for accounting
443 * these specific fault cases.
445 kprobes_inc_nmissed_count(cur);
448 * We come here because instructions in the pre/post
449 * handler caused the page_fault, this could happen
450 * if handler tries to access user space by
451 * copy_from_user(), get_user() etc. Let the
452 * user-specified handler try to fix it first.
454 if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
455 return 1;
458 * In case the user-specified fault handler returned
459 * zero, try to fix up.
461 if ((entry = search_exception_tables(regs->pc)) != NULL) {
462 regs->pc = entry->fixup;
463 return 1;
467 * fixup_exception() could not handle it,
468 * Let do_page_fault() fix it.
470 break;
471 default:
472 break;
475 return 0;
479 * Wrapper routine to for handling exceptions.
481 int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
482 unsigned long val, void *data)
484 struct kprobe *p = NULL;
485 struct die_args *args = (struct die_args *)data;
486 int ret = NOTIFY_DONE;
487 kprobe_opcode_t *addr = NULL;
488 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
490 addr = (kprobe_opcode_t *) (args->regs->pc);
491 if (val == DIE_TRAP) {
492 if (!kprobe_running()) {
493 if (kprobe_handler(args->regs)) {
494 ret = NOTIFY_STOP;
495 } else {
496 /* Not a kprobe trap */
497 ret = NOTIFY_DONE;
499 } else {
500 p = get_kprobe(addr);
501 if ((kcb->kprobe_status == KPROBE_HIT_SS) ||
502 (kcb->kprobe_status == KPROBE_REENTER)) {
503 if (post_kprobe_handler(args->regs))
504 ret = NOTIFY_STOP;
505 } else {
506 if (kprobe_handler(args->regs))
507 ret = NOTIFY_STOP;
512 return ret;
515 static struct kprobe trampoline_p = {
516 .addr = (kprobe_opcode_t *)&kretprobe_trampoline,
517 .pre_handler = trampoline_probe_handler
520 int __init arch_init_kprobes(void)
522 return register_kprobe(&trampoline_p);