1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License").  You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 *
22 * $FreeBSD$
23 */
24/*
25 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
26 * Use is subject to license terms.
27 */
28#include <sys/cdefs.h>
29
30#include <sys/param.h>
31#include <sys/systm.h>
32#include <sys/kernel.h>
33#include <sys/stack.h>
34#include <sys/pcpu.h>
35
36#include <machine/frame.h>
37#include <machine/md_var.h>
38#include <machine/reg.h>
39
40#include <vm/vm.h>
41#include <vm/vm_param.h>
42#include <vm/pmap.h>
43
44#include <machine/db_machdep.h>
45#include <machine/md_var.h>
46#include <machine/mips_opcode.h>
47#include <ddb/db_sym.h>
48#include <ddb/ddb.h>
49#include <sys/kdb.h>
50
51#include "regset.h"
52
53#ifdef __mips_n64
54#define	MIPS_IS_VALID_KERNELADDR(reg)	((((reg) & 3) == 0) && \
55					((vm_offset_t)(reg) >= MIPS_XKPHYS_START))
56#else
57#define	MIPS_IS_VALID_KERNELADDR(reg)	((((reg) & 3) == 0) && \
58					((vm_offset_t)(reg) >= MIPS_KSEG0_START))
59#endif
60
61
62
63/*
64 * Wee need some reasonable default to prevent backtrace code
65 * from wandering too far
66 */
67#define	MAX_FUNCTION_SIZE 0x10000
68#define	MAX_PROLOGUE_SIZE 0x100
69
70uint8_t dtrace_fuword8_nocheck(void *);
71uint16_t dtrace_fuword16_nocheck(void *);
72uint32_t dtrace_fuword32_nocheck(void *);
73uint64_t dtrace_fuword64_nocheck(void *);
74
75static int dtrace_next_frame(register_t *pc, register_t *sp, register_t *args, int *valid_args);
76static int dtrace_next_uframe(register_t *pc, register_t *sp, register_t *ra);
77
78void
79dtrace_getpcstack(pc_t *pcstack, int pcstack_limit, int aframes,
80    uint32_t *intrpc)
81{
82	int depth = 0;
83	vm_offset_t callpc;
84	pc_t caller = (pc_t) solaris_cpu[curcpu].cpu_dtrace_caller;
85	register_t sp, ra, pc;
86
87	if (intrpc != 0)
88		pcstack[depth++] = (pc_t) intrpc;
89
90	aframes++;
91
92	sp = (register_t)(intptr_t)__builtin_frame_address(0);
93	ra = (register_t)(intptr_t)__builtin_return_address(0);
94
95       	__asm __volatile(
96		"jal 99f\n"
97		"nop\n"
98		"99:\n"
99		"move %0, $31\n" /* get ra */
100		"move $31, %1\n" /* restore ra */
101		: "=r" (pc)
102		: "r" (ra));
103
104	while (depth < pcstack_limit) {
105
106		callpc = pc;
107
108		if (aframes > 0) {
109			aframes--;
110			if ((aframes == 0) && (caller != 0)) {
111				pcstack[depth++] = caller;
112			}
113		}
114		else {
115			pcstack[depth++] = callpc;
116		}
117
118		if (dtrace_next_frame(&pc, &sp, NULL, NULL) < 0)
119			break;
120	}
121
122	for (; depth < pcstack_limit; depth++) {
123		pcstack[depth] = 0;
124	}
125}
126
127void
128dtrace_getupcstack(uint64_t *pcstack, int pcstack_limit)
129{
130	proc_t *p = curproc;
131	struct trapframe *tf;
132	register_t sp, ra, pc;
133	volatile uint16_t *flags =
134	    (volatile uint16_t *)&cpu_core[curcpu].cpuc_dtrace_flags;
135
136	if (*flags & CPU_DTRACE_FAULT)
137		return;
138
139	if (pcstack_limit <= 0)
140		return;
141
142	/*
143	 * If there's no user context we still need to zero the stack.
144	 */
145	if (p == NULL || (tf = curthread->td_frame) == NULL)
146		goto zero;
147
148	*pcstack++ = (uint64_t)p->p_pid;
149	pcstack_limit--;
150
151	if (pcstack_limit <= 0)
152		return;
153
154	pc = (uint64_t)tf->pc;
155	sp = (uint64_t)tf->sp;
156	ra = (uint64_t)tf->ra;
157	*pcstack++ = (uint64_t)tf->pc;
158
159	/*
160	 * Unwind, and unwind, and unwind
161	 */
162	while (1) {
163		if (dtrace_next_uframe(&pc, &sp, &ra) < 0)
164			break;
165
166		*pcstack++ = pc;
167		pcstack_limit--;
168
169		if (pcstack_limit <= 0)
170			break;
171	}
172
173zero:
174	while (pcstack_limit-- > 0)
175		*pcstack++ = 0;
176}
177
178int
179dtrace_getustackdepth(void)
180{
181	int n = 0;
182	proc_t *p = curproc;
183	struct trapframe *tf;
184	register_t sp, ra, pc;
185	volatile uint16_t *flags =
186	    (volatile uint16_t *)&cpu_core[curcpu].cpuc_dtrace_flags;
187
188	if (*flags & CPU_DTRACE_FAULT)
189		return (0);
190
191	if (p == NULL || (tf = curthread->td_frame) == NULL)
192		return (0);
193
194	pc = (uint64_t)tf->pc;
195	sp = (uint64_t)tf->sp;
196	ra = (uint64_t)tf->ra;
197	n++;
198
199	/*
200	 * Unwind, and unwind, and unwind
201	 */
202	while (1) {
203		if (dtrace_next_uframe(&pc, &sp, &ra) < 0)
204			break;
205		n++;
206	}
207
208	return (n);
209}
210
211void
212dtrace_getufpstack(uint64_t *pcstack, uint64_t *fpstack, int pcstack_limit)
213{
214	printf("IMPLEMENT ME: %s\n", __func__);
215}
216
217/*ARGSUSED*/
218uint64_t
219dtrace_getarg(int arg, int aframes)
220{
221	int i;
222	register_t sp, ra, pc;
223	/* XXX: Fix this ugly code */
224	register_t args[8];
225	int valid[8];
226
227	sp = (register_t)(intptr_t)__builtin_frame_address(0);
228	ra = (register_t)(intptr_t)__builtin_return_address(0);
229
230       	__asm __volatile(
231		"jal 99f\n"
232		"nop\n"
233		"99:\n"
234		"move %0, $31\n" /* get ra */
235		"move $31, %1\n" /* restore ra */
236		: "=r" (pc)
237		: "r" (ra));
238
239	for (i = 0; i <= aframes + 1; i++) {
240		if (dtrace_next_frame(&pc, &sp, args, valid) < 0) {
241			printf("%s: stack ends at frame #%d\n", __func__, i);
242			return (0);
243		}
244	}
245
246	if (arg < 8) {
247		if (valid[arg])
248			return (args[arg]);
249		else
250			printf("%s: request arg%d is not valid\n", __func__, arg);
251	}
252
253	return (0);
254}
255
256int
257dtrace_getstackdepth(int aframes)
258{
259	register_t sp, ra, pc;
260	int depth = 0;
261
262	sp = (register_t)(intptr_t)__builtin_frame_address(0);
263	ra = (register_t)(intptr_t)__builtin_return_address(0);
264
265       	__asm __volatile(
266		"jal 99f\n"
267		"nop\n"
268		"99:\n"
269		"move %0, $31\n" /* get ra */
270		"move $31, %1\n" /* restore ra */
271		: "=r" (pc)
272		: "r" (ra));
273
274	for (;;) {
275		if (dtrace_next_frame(&pc, &sp, NULL, NULL) < 0)
276			break;
277		depth++;
278	}
279
280	if (depth < aframes)
281		return 0;
282	else
283		return depth - aframes;
284}
285
286ulong_t
287dtrace_getreg(struct trapframe *rp, uint_t reg)
288{
289
290	return (0);
291}
292
293static int
294dtrace_next_frame(register_t *pc, register_t *sp,
295	register_t *args, int *valid_args)
296{
297	InstFmt i;
298	/*
299	 * Arrays for a0..a3 registers and flags if content
300	 * of these registers is valid, e.g. obtained from the stack
301	 */
302	uintptr_t va;
303	unsigned instr, mask;
304	unsigned int frames = 0;
305	int more, stksize;
306	register_t ra = 0;
307	int arg, r;
308	vm_offset_t addr;
309
310	/*
311	 * Invalidate arguments values
312	 */
313	if (valid_args) {
314		for (r = 0; r < 8; r++)
315			valid_args[r] = 0;
316	}
317
318	/* Jump here after a nonstandard (interrupt handler) frame */
319	stksize = 0;
320	if (frames++ > 100) {
321		/* return breaks stackframe-size heuristics with gcc -O2 */
322		goto error;	/* XXX */
323	}
324
325	/* check for bad SP: could foul up next frame */
326	if (!MIPS_IS_VALID_KERNELADDR(*sp)) {
327		goto error;
328	}
329
330	/* check for bad PC */
331	if (!MIPS_IS_VALID_KERNELADDR(*pc)) {
332		goto error;
333	}
334
335	/*
336	 * Find the beginning of the current subroutine by scanning
337	 * backwards from the current PC for the end of the previous
338	 * subroutine.
339	 */
340	va = *pc - sizeof(int);
341	while (1) {
342		instr = kdbpeek((int *)va);
343
344		/* [d]addiu sp,sp,-X */
345		if (((instr & 0xffff8000) == 0x27bd8000)
346		    || ((instr & 0xffff8000) == 0x67bd8000))
347			break;
348
349		/* jr	ra */
350		if (instr == 0x03e00008) {
351			/* skip over branch-delay slot instruction */
352			va += 2 * sizeof(int);
353			break;
354		}
355
356		va -= sizeof(int);
357	}
358
359	/* skip over nulls which might separate .o files */
360	while ((instr = kdbpeek((int *)va)) == 0)
361		va += sizeof(int);
362
363	/* scan forwards to find stack size and any saved registers */
364	stksize = 0;
365	more = 3;
366	mask = 0;
367	for (; more; va += sizeof(int),
368	    more = (more == 3) ? 3 : more - 1) {
369		/* stop if hit our current position */
370		if (va >= *pc)
371			break;
372		instr = kdbpeek((int *)va);
373		i.word = instr;
374		switch (i.JType.op) {
375		case OP_SPECIAL:
376			switch (i.RType.func) {
377			case OP_JR:
378			case OP_JALR:
379				more = 2;	/* stop after next instruction */
380				break;
381
382			case OP_SYSCALL:
383			case OP_BREAK:
384				more = 1;	/* stop now */
385			};
386			break;
387
388		case OP_BCOND:
389		case OP_J:
390		case OP_JAL:
391		case OP_BEQ:
392		case OP_BNE:
393		case OP_BLEZ:
394		case OP_BGTZ:
395			more = 2;	/* stop after next instruction */
396			break;
397
398		case OP_COP0:
399		case OP_COP1:
400		case OP_COP2:
401		case OP_COP3:
402			switch (i.RType.rs) {
403			case OP_BCx:
404			case OP_BCy:
405				more = 2;	/* stop after next instruction */
406			};
407			break;
408
409		case OP_SW:
410			/* look for saved registers on the stack */
411			if (i.IType.rs != 29)
412				break;
413			/* only restore the first one */
414			if (mask & (1 << i.IType.rt))
415				break;
416			mask |= (1 << i.IType.rt);
417			addr = (vm_offset_t)(*sp + (short)i.IType.imm);
418			switch (i.IType.rt) {
419			case 4:/* a0 */
420			case 5:/* a1 */
421			case 6:/* a2 */
422			case 7:/* a3 */
423#if defined(__mips_n64) || defined(__mips_n32)
424			case 8:/* a4 */
425			case 9:/* a5 */
426			case 10:/* a6 */
427			case 11:/* a7 */
428#endif
429				arg = i.IType.rt - 4;
430				if (args)
431					args[arg] = kdbpeek((int*)addr);
432				if (valid_args)
433					valid_args[arg] = 1;
434				break;
435			case 31:	/* ra */
436				ra = kdbpeek((int *)addr);
437			}
438			break;
439
440		case OP_SD:
441			/* look for saved registers on the stack */
442			if (i.IType.rs != 29)
443				break;
444			/* only restore the first one */
445			if (mask & (1 << i.IType.rt))
446				break;
447			mask |= (1 << i.IType.rt);
448			addr = (vm_offset_t)(*sp + (short)i.IType.imm);
449			switch (i.IType.rt) {
450			case 4:/* a0 */
451			case 5:/* a1 */
452			case 6:/* a2 */
453			case 7:/* a3 */
454#if defined(__mips_n64) || defined(__mips_n32)
455			case 8:/* a4 */
456			case 9:/* a5 */
457			case 10:/* a6 */
458			case 11:/* a7 */
459#endif
460				arg = i.IType.rt - 4;
461				if (args)
462					args[arg] = kdbpeekd((int *)addr);
463				if (valid_args)
464					valid_args[arg] = 1;
465				break;
466
467			case 31:	/* ra */
468				ra = kdbpeekd((int *)addr);
469			}
470			break;
471
472		case OP_ADDI:
473		case OP_ADDIU:
474		case OP_DADDI:
475		case OP_DADDIU:
476			/* look for stack pointer adjustment */
477			if (i.IType.rs != 29 || i.IType.rt != 29)
478				break;
479			stksize = -((short)i.IType.imm);
480		}
481	}
482
483	if (!MIPS_IS_VALID_KERNELADDR(ra))
484		return (-1);
485
486	*pc = ra;
487	*sp += stksize;
488
489#if defined(__mips_o32)
490	/*
491	 * For MIPS32 fill out arguments 5..8 from the stack
492	 */
493	for (arg = 4; arg < 8; arg++) {
494		addr = (vm_offset_t)(*sp + arg*sizeof(register_t));
495		if (args)
496			args[arg] = kdbpeekd((int *)addr);
497		if (valid_args)
498			valid_args[arg] = 1;
499	}
500#endif
501
502	return (0);
503error:
504	return (-1);
505}
506
507static int
508dtrace_next_uframe(register_t *pc, register_t *sp, register_t *ra)
509{
510	int offset, registers_on_stack;
511	uint32_t opcode, mask;
512	register_t function_start;
513	int stksize;
514	InstFmt i;
515
516	volatile uint16_t *flags =
517	    (volatile uint16_t *)&cpu_core[curcpu].cpuc_dtrace_flags;
518
519	registers_on_stack = 0;
520	mask = 0;
521	function_start = 0;
522	offset = 0;
523	stksize = 0;
524
525	while (offset < MAX_FUNCTION_SIZE) {
526		opcode = dtrace_fuword32((void *)(vm_offset_t)(*pc - offset));
527
528		if (*flags & CPU_DTRACE_FAULT)
529			goto fault;
530
531		/* [d]addiu sp, sp, -X*/
532		if (((opcode & 0xffff8000) == 0x27bd8000)
533		    || ((opcode & 0xffff8000) == 0x67bd8000)) {
534			function_start = *pc - offset;
535			registers_on_stack = 1;
536			break;
537		}
538
539		/* lui gp, X */
540		if ((opcode & 0xffff8000) == 0x3c1c0000) {
541			/*
542			 * Function might start with this instruction
543			 * Keep an eye on "jr ra" and sp correction
544			 * with positive value further on
545			 */
546			function_start = *pc - offset;
547		}
548
549		if (function_start) {
550			/*
551			 * Stop looking further. Possible end of
552			 * function instruction: it means there is no
553			 * stack modifications, sp is unchanged
554			 */
555
556			/* [d]addiu sp,sp,X */
557			if (((opcode & 0xffff8000) == 0x27bd0000)
558			    || ((opcode & 0xffff8000) == 0x67bd0000))
559				break;
560
561			if (opcode == 0x03e00008)
562				break;
563		}
564
565		offset += sizeof(int);
566	}
567
568	if (!function_start)
569		return (-1);
570
571	if (registers_on_stack) {
572		offset = 0;
573		while ((offset < MAX_PROLOGUE_SIZE)
574		    && ((function_start + offset) < *pc)) {
575			i.word =
576			    dtrace_fuword32((void *)(vm_offset_t)(function_start + offset));
577			switch (i.JType.op) {
578			case OP_SW:
579				/* look for saved registers on the stack */
580				if (i.IType.rs != 29)
581					break;
582				/* only restore the first one */
583				if (mask & (1 << i.IType.rt))
584					break;
585				mask |= (1 << i.IType.rt);
586				if (i.IType.rt == 31)
587					*ra = dtrace_fuword32((void *)(vm_offset_t)(*sp + (short)i.IType.imm));
588				break;
589
590			case OP_SD:
591				/* look for saved registers on the stack */
592				if (i.IType.rs != 29)
593					break;
594				/* only restore the first one */
595				if (mask & (1 << i.IType.rt))
596					break;
597				mask |= (1 << i.IType.rt);
598				/* ra */
599				if (i.IType.rt == 31)
600					*ra = dtrace_fuword64((void *)(vm_offset_t)(*sp + (short)i.IType.imm));
601			break;
602
603			case OP_ADDI:
604			case OP_ADDIU:
605			case OP_DADDI:
606			case OP_DADDIU:
607				/* look for stack pointer adjustment */
608				if (i.IType.rs != 29 || i.IType.rt != 29)
609					break;
610				stksize = -((short)i.IType.imm);
611			}
612
613			offset += sizeof(int);
614
615			if (*flags & CPU_DTRACE_FAULT)
616				goto fault;
617		}
618	}
619
620	/*
621	 * We reached the end of backtrace
622	 */
623	if (*pc == *ra)
624		return (-1);
625
626	*pc = *ra;
627	*sp += stksize;
628
629	return (0);
630fault:
631	/*
632	 * We just got lost in backtrace, no big deal
633	 */
634	*flags &= ~CPU_DTRACE_FAULT;
635	return (-1);
636}
637
638static int
639dtrace_copycheck(uintptr_t uaddr, uintptr_t kaddr, size_t size)
640{
641
642	if (uaddr + size > VM_MAXUSER_ADDRESS || uaddr + size < uaddr) {
643		DTRACE_CPUFLAG_SET(CPU_DTRACE_BADADDR);
644		cpu_core[curcpu].cpuc_dtrace_illval = uaddr;
645		return (0);
646	}
647
648	return (1);
649}
650
651void
652dtrace_copyin(uintptr_t uaddr, uintptr_t kaddr, size_t size,
653    volatile uint16_t *flags)
654{
655	if (dtrace_copycheck(uaddr, kaddr, size))
656		dtrace_copy(uaddr, kaddr, size);
657}
658
659void
660dtrace_copyout(uintptr_t kaddr, uintptr_t uaddr, size_t size,
661    volatile uint16_t *flags)
662{
663	if (dtrace_copycheck(uaddr, kaddr, size))
664		dtrace_copy(kaddr, uaddr, size);
665}
666
667void
668dtrace_copyinstr(uintptr_t uaddr, uintptr_t kaddr, size_t size,
669    volatile uint16_t *flags)
670{
671	if (dtrace_copycheck(uaddr, kaddr, size))
672		dtrace_copystr(uaddr, kaddr, size, flags);
673}
674
675void
676dtrace_copyoutstr(uintptr_t kaddr, uintptr_t uaddr, size_t size,
677    volatile uint16_t *flags)
678{
679	if (dtrace_copycheck(uaddr, kaddr, size))
680		dtrace_copystr(kaddr, uaddr, size, flags);
681}
682
683uint8_t
684dtrace_fuword8(void *uaddr)
685{
686	if ((uintptr_t)uaddr > VM_MAXUSER_ADDRESS) {
687		DTRACE_CPUFLAG_SET(CPU_DTRACE_BADADDR);
688		cpu_core[curcpu].cpuc_dtrace_illval = (uintptr_t)uaddr;
689		return (0);
690	}
691	return (dtrace_fuword8_nocheck(uaddr));
692}
693
694uint16_t
695dtrace_fuword16(void *uaddr)
696{
697	if ((uintptr_t)uaddr > VM_MAXUSER_ADDRESS) {
698		DTRACE_CPUFLAG_SET(CPU_DTRACE_BADADDR);
699		cpu_core[curcpu].cpuc_dtrace_illval = (uintptr_t)uaddr;
700		return (0);
701	}
702	return (dtrace_fuword16_nocheck(uaddr));
703}
704
705uint32_t
706dtrace_fuword32(void *uaddr)
707{
708	if ((uintptr_t)uaddr > VM_MAXUSER_ADDRESS) {
709		DTRACE_CPUFLAG_SET(CPU_DTRACE_BADADDR);
710		cpu_core[curcpu].cpuc_dtrace_illval = (uintptr_t)uaddr;
711		return (0);
712	}
713	return (dtrace_fuword32_nocheck(uaddr));
714}
715
716uint64_t
717dtrace_fuword64(void *uaddr)
718{
719	if ((uintptr_t)uaddr > VM_MAXUSER_ADDRESS) {
720		DTRACE_CPUFLAG_SET(CPU_DTRACE_BADADDR);
721		cpu_core[curcpu].cpuc_dtrace_illval = (uintptr_t)uaddr;
722		return (0);
723	}
724	return (dtrace_fuword64_nocheck(uaddr));
725}
726