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-rw-r--r--arch/sparc64/kernel/kprobes.c593
1 files changed, 0 insertions, 593 deletions
diff --git a/arch/sparc64/kernel/kprobes.c b/arch/sparc64/kernel/kprobes.c
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index 201a6e547e4a..000000000000
--- a/arch/sparc64/kernel/kprobes.c
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1/* arch/sparc64/kernel/kprobes.c
2 *
3 * Copyright (C) 2004 David S. Miller <davem@davemloft.net>
4 */
5
6#include <linux/kernel.h>
7#include <linux/kprobes.h>
8#include <linux/module.h>
9#include <linux/kdebug.h>
10#include <asm/signal.h>
11#include <asm/cacheflush.h>
12#include <asm/uaccess.h>
13
14/* We do not have hardware single-stepping on sparc64.
15 * So we implement software single-stepping with breakpoint
16 * traps. The top-level scheme is similar to that used
17 * in the x86 kprobes implementation.
18 *
19 * In the kprobe->ainsn.insn[] array we store the original
20 * instruction at index zero and a break instruction at
21 * index one.
22 *
23 * When we hit a kprobe we:
24 * - Run the pre-handler
25 * - Remember "regs->tnpc" and interrupt level stored in
26 * "regs->tstate" so we can restore them later
27 * - Disable PIL interrupts
28 * - Set regs->tpc to point to kprobe->ainsn.insn[0]
29 * - Set regs->tnpc to point to kprobe->ainsn.insn[1]
30 * - Mark that we are actively in a kprobe
31 *
32 * At this point we wait for the second breakpoint at
33 * kprobe->ainsn.insn[1] to hit. When it does we:
34 * - Run the post-handler
35 * - Set regs->tpc to "remembered" regs->tnpc stored above,
36 * restore the PIL interrupt level in "regs->tstate" as well
37 * - Make any adjustments necessary to regs->tnpc in order
38 * to handle relative branches correctly. See below.
39 * - Mark that we are no longer actively in a kprobe.
40 */
41
42DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
43DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
44
45struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
46
47int __kprobes arch_prepare_kprobe(struct kprobe *p)
48{
49 p->ainsn.insn[0] = *p->addr;
50 flushi(&p->ainsn.insn[0]);
51
52 p->ainsn.insn[1] = BREAKPOINT_INSTRUCTION_2;
53 flushi(&p->ainsn.insn[1]);
54
55 p->opcode = *p->addr;
56 return 0;
57}
58
59void __kprobes arch_arm_kprobe(struct kprobe *p)
60{
61 *p->addr = BREAKPOINT_INSTRUCTION;
62 flushi(p->addr);
63}
64
65void __kprobes arch_disarm_kprobe(struct kprobe *p)
66{
67 *p->addr = p->opcode;
68 flushi(p->addr);
69}
70
71static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
72{
73 kcb->prev_kprobe.kp = kprobe_running();
74 kcb->prev_kprobe.status = kcb->kprobe_status;
75 kcb->prev_kprobe.orig_tnpc = kcb->kprobe_orig_tnpc;
76 kcb->prev_kprobe.orig_tstate_pil = kcb->kprobe_orig_tstate_pil;
77}
78
79static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
80{
81 __get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp;
82 kcb->kprobe_status = kcb->prev_kprobe.status;
83 kcb->kprobe_orig_tnpc = kcb->prev_kprobe.orig_tnpc;
84 kcb->kprobe_orig_tstate_pil = kcb->prev_kprobe.orig_tstate_pil;
85}
86
87static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
88 struct kprobe_ctlblk *kcb)
89{
90 __get_cpu_var(current_kprobe) = p;
91 kcb->kprobe_orig_tnpc = regs->tnpc;
92 kcb->kprobe_orig_tstate_pil = (regs->tstate & TSTATE_PIL);
93}
94
95static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs,
96 struct kprobe_ctlblk *kcb)
97{
98 regs->tstate |= TSTATE_PIL;
99
100 /*single step inline, if it a breakpoint instruction*/
101 if (p->opcode == BREAKPOINT_INSTRUCTION) {
102 regs->tpc = (unsigned long) p->addr;
103 regs->tnpc = kcb->kprobe_orig_tnpc;
104 } else {
105 regs->tpc = (unsigned long) &p->ainsn.insn[0];
106 regs->tnpc = (unsigned long) &p->ainsn.insn[1];
107 }
108}
109
110static int __kprobes kprobe_handler(struct pt_regs *regs)
111{
112 struct kprobe *p;
113 void *addr = (void *) regs->tpc;
114 int ret = 0;
115 struct kprobe_ctlblk *kcb;
116
117 /*
118 * We don't want to be preempted for the entire
119 * duration of kprobe processing
120 */
121 preempt_disable();
122 kcb = get_kprobe_ctlblk();
123
124 if (kprobe_running()) {
125 p = get_kprobe(addr);
126 if (p) {
127 if (kcb->kprobe_status == KPROBE_HIT_SS) {
128 regs->tstate = ((regs->tstate & ~TSTATE_PIL) |
129 kcb->kprobe_orig_tstate_pil);
130 goto no_kprobe;
131 }
132 /* We have reentered the kprobe_handler(), since
133 * another probe was hit while within the handler.
134 * We here save the original kprobes variables and
135 * just single step on the instruction of the new probe
136 * without calling any user handlers.
137 */
138 save_previous_kprobe(kcb);
139 set_current_kprobe(p, regs, kcb);
140 kprobes_inc_nmissed_count(p);
141 kcb->kprobe_status = KPROBE_REENTER;
142 prepare_singlestep(p, regs, kcb);
143 return 1;
144 } else {
145 if (*(u32 *)addr != BREAKPOINT_INSTRUCTION) {
146 /* The breakpoint instruction was removed by
147 * another cpu right after we hit, no further
148 * handling of this interrupt is appropriate
149 */
150 ret = 1;
151 goto no_kprobe;
152 }
153 p = __get_cpu_var(current_kprobe);
154 if (p->break_handler && p->break_handler(p, regs))
155 goto ss_probe;
156 }
157 goto no_kprobe;
158 }
159
160 p = get_kprobe(addr);
161 if (!p) {
162 if (*(u32 *)addr != BREAKPOINT_INSTRUCTION) {
163 /*
164 * The breakpoint instruction was removed right
165 * after we hit it. Another cpu has removed
166 * either a probepoint or a debugger breakpoint
167 * at this address. In either case, no further
168 * handling of this interrupt is appropriate.
169 */
170 ret = 1;
171 }
172 /* Not one of ours: let kernel handle it */
173 goto no_kprobe;
174 }
175
176 set_current_kprobe(p, regs, kcb);
177 kcb->kprobe_status = KPROBE_HIT_ACTIVE;
178 if (p->pre_handler && p->pre_handler(p, regs))
179 return 1;
180
181ss_probe:
182 prepare_singlestep(p, regs, kcb);
183 kcb->kprobe_status = KPROBE_HIT_SS;
184 return 1;
185
186no_kprobe:
187 preempt_enable_no_resched();
188 return ret;
189}
190
191/* If INSN is a relative control transfer instruction,
192 * return the corrected branch destination value.
193 *
194 * regs->tpc and regs->tnpc still hold the values of the
195 * program counters at the time of trap due to the execution
196 * of the BREAKPOINT_INSTRUCTION_2 at p->ainsn.insn[1]
197 *
198 */
199static unsigned long __kprobes relbranch_fixup(u32 insn, struct kprobe *p,
200 struct pt_regs *regs)
201{
202 unsigned long real_pc = (unsigned long) p->addr;
203
204 /* Branch not taken, no mods necessary. */
205 if (regs->tnpc == regs->tpc + 0x4UL)
206 return real_pc + 0x8UL;
207
208 /* The three cases are call, branch w/prediction,
209 * and traditional branch.
210 */
211 if ((insn & 0xc0000000) == 0x40000000 ||
212 (insn & 0xc1c00000) == 0x00400000 ||
213 (insn & 0xc1c00000) == 0x00800000) {
214 unsigned long ainsn_addr;
215
216 ainsn_addr = (unsigned long) &p->ainsn.insn[0];
217
218 /* The instruction did all the work for us
219 * already, just apply the offset to the correct
220 * instruction location.
221 */
222 return (real_pc + (regs->tnpc - ainsn_addr));
223 }
224
225 /* It is jmpl or some other absolute PC modification instruction,
226 * leave NPC as-is.
227 */
228 return regs->tnpc;
229}
230
231/* If INSN is an instruction which writes it's PC location
232 * into a destination register, fix that up.
233 */
234static void __kprobes retpc_fixup(struct pt_regs *regs, u32 insn,
235 unsigned long real_pc)
236{
237 unsigned long *slot = NULL;
238
239 /* Simplest case is 'call', which always uses %o7 */
240 if ((insn & 0xc0000000) == 0x40000000) {
241 slot = &regs->u_regs[UREG_I7];
242 }
243
244 /* 'jmpl' encodes the register inside of the opcode */
245 if ((insn & 0xc1f80000) == 0x81c00000) {
246 unsigned long rd = ((insn >> 25) & 0x1f);
247
248 if (rd <= 15) {
249 slot = &regs->u_regs[rd];
250 } else {
251 /* Hard case, it goes onto the stack. */
252 flushw_all();
253
254 rd -= 16;
255 slot = (unsigned long *)
256 (regs->u_regs[UREG_FP] + STACK_BIAS);
257 slot += rd;
258 }
259 }
260 if (slot != NULL)
261 *slot = real_pc;
262}
263
264/*
265 * Called after single-stepping. p->addr is the address of the
266 * instruction which has been replaced by the breakpoint
267 * instruction. To avoid the SMP problems that can occur when we
268 * temporarily put back the original opcode to single-step, we
269 * single-stepped a copy of the instruction. The address of this
270 * copy is &p->ainsn.insn[0].
271 *
272 * This function prepares to return from the post-single-step
273 * breakpoint trap.
274 */
275static void __kprobes resume_execution(struct kprobe *p,
276 struct pt_regs *regs, struct kprobe_ctlblk *kcb)
277{
278 u32 insn = p->ainsn.insn[0];
279
280 regs->tnpc = relbranch_fixup(insn, p, regs);
281
282 /* This assignment must occur after relbranch_fixup() */
283 regs->tpc = kcb->kprobe_orig_tnpc;
284
285 retpc_fixup(regs, insn, (unsigned long) p->addr);
286
287 regs->tstate = ((regs->tstate & ~TSTATE_PIL) |
288 kcb->kprobe_orig_tstate_pil);
289}
290
291static int __kprobes post_kprobe_handler(struct pt_regs *regs)
292{
293 struct kprobe *cur = kprobe_running();
294 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
295
296 if (!cur)
297 return 0;
298
299 if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
300 kcb->kprobe_status = KPROBE_HIT_SSDONE;
301 cur->post_handler(cur, regs, 0);
302 }
303
304 resume_execution(cur, regs, kcb);
305
306 /*Restore back the original saved kprobes variables and continue. */
307 if (kcb->kprobe_status == KPROBE_REENTER) {
308 restore_previous_kprobe(kcb);
309 goto out;
310 }
311 reset_current_kprobe();
312out:
313 preempt_enable_no_resched();
314
315 return 1;
316}
317
318int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
319{
320 struct kprobe *cur = kprobe_running();
321 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
322 const struct exception_table_entry *entry;
323
324 switch(kcb->kprobe_status) {
325 case KPROBE_HIT_SS:
326 case KPROBE_REENTER:
327 /*
328 * We are here because the instruction being single
329 * stepped caused a page fault. We reset the current
330 * kprobe and the tpc points back to the probe address
331 * and allow the page fault handler to continue as a
332 * normal page fault.
333 */
334 regs->tpc = (unsigned long)cur->addr;
335 regs->tnpc = kcb->kprobe_orig_tnpc;
336 regs->tstate = ((regs->tstate & ~TSTATE_PIL) |
337 kcb->kprobe_orig_tstate_pil);
338 if (kcb->kprobe_status == KPROBE_REENTER)
339 restore_previous_kprobe(kcb);
340 else
341 reset_current_kprobe();
342 preempt_enable_no_resched();
343 break;
344 case KPROBE_HIT_ACTIVE:
345 case KPROBE_HIT_SSDONE:
346 /*
347 * We increment the nmissed count for accounting,
348 * we can also use npre/npostfault count for accouting
349 * these specific fault cases.
350 */
351 kprobes_inc_nmissed_count(cur);
352
353 /*
354 * We come here because instructions in the pre/post
355 * handler caused the page_fault, this could happen
356 * if handler tries to access user space by
357 * copy_from_user(), get_user() etc. Let the
358 * user-specified handler try to fix it first.
359 */
360 if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
361 return 1;
362
363 /*
364 * In case the user-specified fault handler returned
365 * zero, try to fix up.
366 */
367
368 entry = search_exception_tables(regs->tpc);
369 if (entry) {
370 regs->tpc = entry->fixup;
371 regs->tnpc = regs->tpc + 4;
372 return 1;
373 }
374
375 /*
376 * fixup_exception() could not handle it,
377 * Let do_page_fault() fix it.
378 */
379 break;
380 default:
381 break;
382 }
383
384 return 0;
385}
386
387/*
388 * Wrapper routine to for handling exceptions.
389 */
390int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
391 unsigned long val, void *data)
392{
393 struct die_args *args = (struct die_args *)data;
394 int ret = NOTIFY_DONE;
395
396 if (args->regs && user_mode(args->regs))
397 return ret;
398
399 switch (val) {
400 case DIE_DEBUG:
401 if (kprobe_handler(args->regs))
402 ret = NOTIFY_STOP;
403 break;
404 case DIE_DEBUG_2:
405 if (post_kprobe_handler(args->regs))
406 ret = NOTIFY_STOP;
407 break;
408 default:
409 break;
410 }
411 return ret;
412}
413
414asmlinkage void __kprobes kprobe_trap(unsigned long trap_level,
415 struct pt_regs *regs)
416{
417 BUG_ON(trap_level != 0x170 && trap_level != 0x171);
418
419 if (user_mode(regs)) {
420 local_irq_enable();
421 bad_trap(regs, trap_level);
422 return;
423 }
424
425 /* trap_level == 0x170 --> ta 0x70
426 * trap_level == 0x171 --> ta 0x71
427 */
428 if (notify_die((trap_level == 0x170) ? DIE_DEBUG : DIE_DEBUG_2,
429 (trap_level == 0x170) ? "debug" : "debug_2",
430 regs, 0, trap_level, SIGTRAP) != NOTIFY_STOP)
431 bad_trap(regs, trap_level);
432}
433
434/* Jprobes support. */
435int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
436{
437 struct jprobe *jp = container_of(p, struct jprobe, kp);
438 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
439
440 memcpy(&(kcb->jprobe_saved_regs), regs, sizeof(*regs));
441
442 regs->tpc = (unsigned long) jp->entry;
443 regs->tnpc = ((unsigned long) jp->entry) + 0x4UL;
444 regs->tstate |= TSTATE_PIL;
445
446 return 1;
447}
448
449void __kprobes jprobe_return(void)
450{
451 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
452 register unsigned long orig_fp asm("g1");
453
454 orig_fp = kcb->jprobe_saved_regs.u_regs[UREG_FP];
455 __asm__ __volatile__("\n"
456"1: cmp %%sp, %0\n\t"
457 "blu,a,pt %%xcc, 1b\n\t"
458 " restore\n\t"
459 ".globl jprobe_return_trap_instruction\n"
460"jprobe_return_trap_instruction:\n\t"
461 "ta 0x70"
462 : /* no outputs */
463 : "r" (orig_fp));
464}
465
466extern void jprobe_return_trap_instruction(void);
467
468int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
469{
470 u32 *addr = (u32 *) regs->tpc;
471 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
472
473 if (addr == (u32 *) jprobe_return_trap_instruction) {
474 memcpy(regs, &(kcb->jprobe_saved_regs), sizeof(*regs));
475 preempt_enable_no_resched();
476 return 1;
477 }
478 return 0;
479}
480
481/* The value stored in the return address register is actually 2
482 * instructions before where the callee will return to.
483 * Sequences usually look something like this
484 *
485 * call some_function <--- return register points here
486 * nop <--- call delay slot
487 * whatever <--- where callee returns to
488 *
489 * To keep trampoline_probe_handler logic simpler, we normalize the
490 * value kept in ri->ret_addr so we don't need to keep adjusting it
491 * back and forth.
492 */
493void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
494 struct pt_regs *regs)
495{
496 ri->ret_addr = (kprobe_opcode_t *)(regs->u_regs[UREG_RETPC] + 8);
497
498 /* Replace the return addr with trampoline addr */
499 regs->u_regs[UREG_RETPC] =
500 ((unsigned long)kretprobe_trampoline) - 8;
501}
502
503/*
504 * Called when the probe at kretprobe trampoline is hit
505 */
506int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
507{
508 struct kretprobe_instance *ri = NULL;
509 struct hlist_head *head, empty_rp;
510 struct hlist_node *node, *tmp;
511 unsigned long flags, orig_ret_address = 0;
512 unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
513
514 INIT_HLIST_HEAD(&empty_rp);
515 kretprobe_hash_lock(current, &head, &flags);
516
517 /*
518 * It is possible to have multiple instances associated with a given
519 * task either because an multiple functions in the call path
520 * have a return probe installed on them, and/or more then one return
521 * return probe was registered for a target function.
522 *
523 * We can handle this because:
524 * - instances are always inserted at the head of the list
525 * - when multiple return probes are registered for the same
526 * function, the first instance's ret_addr will point to the
527 * real return address, and all the rest will point to
528 * kretprobe_trampoline
529 */
530 hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
531 if (ri->task != current)
532 /* another task is sharing our hash bucket */
533 continue;
534
535 if (ri->rp && ri->rp->handler)
536 ri->rp->handler(ri, regs);
537
538 orig_ret_address = (unsigned long)ri->ret_addr;
539 recycle_rp_inst(ri, &empty_rp);
540
541 if (orig_ret_address != trampoline_address)
542 /*
543 * This is the real return address. Any other
544 * instances associated with this task are for
545 * other calls deeper on the call stack
546 */
547 break;
548 }
549
550 kretprobe_assert(ri, orig_ret_address, trampoline_address);
551 regs->tpc = orig_ret_address;
552 regs->tnpc = orig_ret_address + 4;
553
554 reset_current_kprobe();
555 kretprobe_hash_unlock(current, &flags);
556 preempt_enable_no_resched();
557
558 hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
559 hlist_del(&ri->hlist);
560 kfree(ri);
561 }
562 /*
563 * By returning a non-zero value, we are telling
564 * kprobe_handler() that we don't want the post_handler
565 * to run (and have re-enabled preemption)
566 */
567 return 1;
568}
569
570void kretprobe_trampoline_holder(void)
571{
572 asm volatile(".global kretprobe_trampoline\n"
573 "kretprobe_trampoline:\n"
574 "\tnop\n"
575 "\tnop\n");
576}
577static struct kprobe trampoline_p = {
578 .addr = (kprobe_opcode_t *) &kretprobe_trampoline,
579 .pre_handler = trampoline_probe_handler
580};
581
582int __init arch_init_kprobes(void)
583{
584 return register_kprobe(&trampoline_p);
585}
586
587int __kprobes arch_trampoline_kprobe(struct kprobe *p)
588{
589 if (p->addr == (kprobe_opcode_t *)&kretprobe_trampoline)
590 return 1;
591
592 return 0;
593}
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-28 17:18:06 -0500