dtrace_isa.c revision 233409 
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: head/sys/cddl/dev/dtrace/mips/dtrace_isa.c 233409 2012-03-24 05:14:37Z gonzo $
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 <machine/vmparam.h>
48#include <ddb/db_sym.h>
49#include <ddb/ddb.h>
50#include <sys/kdb.h>
51
52#include "regset.h"
53
54#ifdef __mips_n64
55#define	MIPS_IS_VALID_KERNELADDR(reg)	((((reg) & 3) == 0) && \
56					((vm_offset_t)(reg) >= MIPS_XKPHYS_START))
57#else
58#define	MIPS_IS_VALID_KERNELADDR(reg)	((((reg) & 3) == 0) && \
59					((vm_offset_t)(reg) >= MIPS_KSEG0_START))
60#endif
61
62
63
64/*
65 * Wee need some reasonable default to prevent backtrace code
66 * from wandering too far
67 */
68#define	MAX_FUNCTION_SIZE 0x10000
69#define	MAX_PROLOGUE_SIZE 0x100
70
71uint8_t dtrace_fuword8_nocheck(void *);
72uint16_t dtrace_fuword16_nocheck(void *);
73uint32_t dtrace_fuword32_nocheck(void *);
74uint64_t dtrace_fuword64_nocheck(void *);
75
76static int dtrace_next_frame(register_t *pc, register_t *sp, register_t *args, int *valid_args);
77static int dtrace_next_uframe(register_t *pc, register_t *sp, register_t *ra);
78
79void
80dtrace_getpcstack(pc_t *pcstack, int pcstack_limit, int aframes,
81    uint32_t *intrpc)
82{
83	int depth = 0;
84	vm_offset_t callpc;
85	pc_t caller = (pc_t) solaris_cpu[curcpu].cpu_dtrace_caller;
86	register_t sp, ra, pc;
87
88	if (intrpc != 0)
89		pcstack[depth++] = (pc_t) intrpc;
90
91	aframes++;
92
93	sp = (register_t)(intptr_t)__builtin_frame_address(0);
94	ra = (register_t)(intptr_t)__builtin_return_address(0);
95
96       	__asm __volatile(
97		"jal 99f\n"
98		"nop\n"
99		"99:\n"
100		"move %0, $31\n" /* get ra */
101		"move $31, %1\n" /* restore ra */
102		: "=r" (pc)
103		: "r" (ra));
104
105	while (depth < pcstack_limit) {
106
107		callpc = pc;
108
109		if (aframes > 0) {
110			aframes--;
111			if ((aframes == 0) && (caller != 0)) {
112				pcstack[depth++] = caller;
113			}
114		}
115		else {
116			pcstack[depth++] = callpc;
117		}
118
119		if (dtrace_next_frame(&pc, &sp, NULL, NULL) < 0)
120			break;
121	}
122
123	for (; depth < pcstack_limit; depth++) {
124		pcstack[depth] = 0;
125	}
126}
127
128void
129dtrace_getupcstack(uint64_t *pcstack, int pcstack_limit)
130{
131	proc_t *p = curproc;
132	struct trapframe *tf;
133	register_t sp, ra, pc;
134	volatile uint16_t *flags =
135	    (volatile uint16_t *)&cpu_core[curcpu].cpuc_dtrace_flags;
136
137	if (*flags & CPU_DTRACE_FAULT)
138		return;
139
140	if (pcstack_limit <= 0)
141		return;
142
143	/*
144	 * If there's no user context we still need to zero the stack.
145	 */
146	if (p == NULL || (tf = curthread->td_frame) == NULL)
147		goto zero;
148
149	*pcstack++ = (uint64_t)p->p_pid;
150	pcstack_limit--;
151
152	if (pcstack_limit <= 0)
153		return;
154
155	pc = (uint64_t)tf->pc;
156	sp = (uint64_t)tf->sp;
157	ra = (uint64_t)tf->ra;
158	*pcstack++ = (uint64_t)tf->pc;
159
160	/*
161	 * Unwind, and unwind, and unwind
162	 */
163	while (1) {
164		if (dtrace_next_uframe(&pc, &sp, &ra) < 0)
165			break;
166
167		*pcstack++ = pc;
168		pcstack_limit--;
169
170		if (pcstack_limit <= 0)
171			break;
172	}
173
174zero:
175	while (pcstack_limit-- > 0)
176		*pcstack++ = 0;
177}
178
179int
180dtrace_getustackdepth(void)
181{
182	int n = 0;
183	proc_t *p = curproc;
184	struct trapframe *tf;
185	register_t sp, ra, pc;
186	volatile uint16_t *flags =
187	    (volatile uint16_t *)&cpu_core[curcpu].cpuc_dtrace_flags;
188
189	if (*flags & CPU_DTRACE_FAULT)
190		return (0);
191
192	if (p == NULL || (tf = curthread->td_frame) == NULL)
193		return (0);
194
195	pc = (uint64_t)tf->pc;
196	sp = (uint64_t)tf->sp;
197	ra = (uint64_t)tf->ra;
198	n++;
199
200	/*
201	 * Unwind, and unwind, and unwind
202	 */
203	while (1) {
204		if (dtrace_next_uframe(&pc, &sp, &ra) < 0)
205			break;
206		n++;
207	}
208
209	return (n);
210}
211
212void
213dtrace_getufpstack(uint64_t *pcstack, uint64_t *fpstack, int pcstack_limit)
214{
215	printf("IMPLEMENT ME: %s\n", __func__);
216}
217
218/*ARGSUSED*/
219uint64_t
220dtrace_getarg(int arg, int aframes)
221{
222	int i;
223	register_t sp, ra, pc;
224	/* XXX: Fix this ugly code */
225	register_t args[8];
226	int valid[8];
227
228	sp = (register_t)(intptr_t)__builtin_frame_address(0);
229	ra = (register_t)(intptr_t)__builtin_return_address(0);
230
231       	__asm __volatile(
232		"jal 99f\n"
233		"nop\n"
234		"99:\n"
235		"move %0, $31\n" /* get ra */
236		"move $31, %1\n" /* restore ra */
237		: "=r" (pc)
238		: "r" (ra));
239
240	for (i = 0; i <= aframes + 1; i++) {
241		if (dtrace_next_frame(&pc, &sp, args, valid) < 0) {
242			printf("%s: stack ends at frame #%d\n", __func__, i);
243			return (0);
244		}
245	}
246
247	if (arg < 8) {
248		if (valid[arg])
249			return (args[arg]);
250		else
251			printf("%s: request arg%d is not valid\n", __func__, arg);
252	}
253
254	return (0);
255}
256
257int
258dtrace_getstackdepth(int aframes)
259{
260	register_t sp, ra, pc;
261	int depth = 0;
262
263	sp = (register_t)(intptr_t)__builtin_frame_address(0);
264	ra = (register_t)(intptr_t)__builtin_return_address(0);
265
266       	__asm __volatile(
267		"jal 99f\n"
268		"nop\n"
269		"99:\n"
270		"move %0, $31\n" /* get ra */
271		"move $31, %1\n" /* restore ra */
272		: "=r" (pc)
273		: "r" (ra));
274
275	for (;;) {
276		if (dtrace_next_frame(&pc, &sp, NULL, NULL) < 0)
277			break;
278		depth++;
279	}
280
281	if (depth < aframes)
282		return 0;
283	else
284		return depth - aframes;
285}
286
287ulong_t
288dtrace_getreg(struct trapframe *rp, uint_t reg)
289{
290
291	return (0);
292}
293
294static int
295dtrace_next_frame(register_t *pc, register_t *sp,
296	register_t *args, int *valid_args)
297{
298	InstFmt i;
299	/*
300	 * Arrays for a0..a3 registers and flags if content
301	 * of these registers is valid, e.g. obtained from the stack
302	 */
303	uintptr_t va;
304	unsigned instr, mask;
305	unsigned int frames = 0;
306	int more, stksize;
307	register_t ra = 0;
308	int arg, r;
309	vm_offset_t addr;
310
311	/*
312	 * Invalidate arguments values
313	 */
314	if (valid_args) {
315		for (r = 0; r < 8; r++)
316			valid_args[r] = 0;
317	}
318
319	/* Jump here after a nonstandard (interrupt handler) frame */
320	stksize = 0;
321	if (frames++ > 100) {
322		/* return breaks stackframe-size heuristics with gcc -O2 */
323		goto error;	/* XXX */
324	}
325
326	/* check for bad SP: could foul up next frame */
327	if (!MIPS_IS_VALID_KERNELADDR(*sp)) {
328		goto error;
329	}
330
331	/* check for bad PC */
332	if (!MIPS_IS_VALID_KERNELADDR(*pc)) {
333		goto error;
334	}
335
336	/*
337	 * Find the beginning of the current subroutine by scanning
338	 * backwards from the current PC for the end of the previous
339	 * subroutine.
340	 */
341	va = *pc - sizeof(int);
342	while (1) {
343		instr = kdbpeek((int *)va);
344
345		/* [d]addiu sp,sp,-X */
346		if (((instr & 0xffff8000) == 0x27bd8000)
347		    || ((instr & 0xffff8000) == 0x67bd8000))
348			break;
349
350		/* jr	ra */
351		if (instr == 0x03e00008) {
352			/* skip over branch-delay slot instruction */
353			va += 2 * sizeof(int);
354			break;
355		}
356
357		va -= sizeof(int);
358	}
359
360	/* skip over nulls which might separate .o files */
361	while ((instr = kdbpeek((int *)va)) == 0)
362		va += sizeof(int);
363
364	/* scan forwards to find stack size and any saved registers */
365	stksize = 0;
366	more = 3;
367	mask = 0;
368	for (; more; va += sizeof(int),
369	    more = (more == 3) ? 3 : more - 1) {
370		/* stop if hit our current position */
371		if (va >= *pc)
372			break;
373		instr = kdbpeek((int *)va);
374		i.word = instr;
375		switch (i.JType.op) {
376		case OP_SPECIAL:
377			switch (i.RType.func) {
378			case OP_JR:
379			case OP_JALR:
380				more = 2;	/* stop after next instruction */
381				break;
382
383			case OP_SYSCALL:
384			case OP_BREAK:
385				more = 1;	/* stop now */
386			};
387			break;
388
389		case OP_BCOND:
390		case OP_J:
391		case OP_JAL:
392		case OP_BEQ:
393		case OP_BNE:
394		case OP_BLEZ:
395		case OP_BGTZ:
396			more = 2;	/* stop after next instruction */
397			break;
398
399		case OP_COP0:
400		case OP_COP1:
401		case OP_COP2:
402		case OP_COP3:
403			switch (i.RType.rs) {
404			case OP_BCx:
405			case OP_BCy:
406				more = 2;	/* stop after next instruction */
407			};
408			break;
409
410		case OP_SW:
411			/* look for saved registers on the stack */
412			if (i.IType.rs != 29)
413				break;
414			/* only restore the first one */
415			if (mask & (1 << i.IType.rt))
416				break;
417			mask |= (1 << i.IType.rt);
418			addr = (vm_offset_t)(*sp + (short)i.IType.imm);
419			switch (i.IType.rt) {
420			case 4:/* a0 */
421			case 5:/* a1 */
422			case 6:/* a2 */
423			case 7:/* a3 */
424#if defined(__mips_n64) || defined(__mips_n32)
425			case 8:/* a4 */
426			case 9:/* a5 */
427			case 10:/* a6 */
428			case 11:/* a7 */
429#endif
430				arg = i.IType.rt - 4;
431				if (args)
432					args[arg] = kdbpeek((int*)addr);
433				if (valid_args)
434					valid_args[arg] = 1;
435				break;
436			case 31:	/* ra */
437				ra = kdbpeek((int *)addr);
438			}
439			break;
440
441		case OP_SD:
442			/* look for saved registers on the stack */
443			if (i.IType.rs != 29)
444				break;
445			/* only restore the first one */
446			if (mask & (1 << i.IType.rt))
447				break;
448			mask |= (1 << i.IType.rt);
449			addr = (vm_offset_t)(*sp + (short)i.IType.imm);
450			switch (i.IType.rt) {
451			case 4:/* a0 */
452			case 5:/* a1 */
453			case 6:/* a2 */
454			case 7:/* a3 */
455#if defined(__mips_n64) || defined(__mips_n32)
456			case 8:/* a4 */
457			case 9:/* a5 */
458			case 10:/* a6 */
459			case 11:/* a7 */
460#endif
461				arg = i.IType.rt - 4;
462				if (args)
463					args[arg] = kdbpeekd((int *)addr);
464				if (valid_args)
465					valid_args[arg] = 1;
466				break;
467
468			case 31:	/* ra */
469				ra = kdbpeekd((int *)addr);
470			}
471			break;
472
473		case OP_ADDI:
474		case OP_ADDIU:
475		case OP_DADDI:
476		case OP_DADDIU:
477			/* look for stack pointer adjustment */
478			if (i.IType.rs != 29 || i.IType.rt != 29)
479				break;
480			stksize = -((short)i.IType.imm);
481		}
482	}
483
484	if (!MIPS_IS_VALID_KERNELADDR(ra))
485		return (-1);
486
487	*pc = ra;
488	*sp += stksize;
489
490	return (0);
491error:
492	return (-1);
493}
494
495static int
496dtrace_next_uframe(register_t *pc, register_t *sp, register_t *ra)
497{
498	int offset, registers_on_stack;
499	uint32_t opcode, mask;
500	register_t function_start;
501	int stksize;
502	InstFmt i;
503
504	registers_on_stack = 0;
505	mask = 0;
506	function_start = 0;
507	offset = 0;
508	stksize = 0;
509
510	while (offset < MAX_FUNCTION_SIZE) {
511		opcode = dtrace_fuword32((void *)(vm_offset_t)(*pc - offset));
512
513		/* [d]addiu sp, sp, -X*/
514		if (((opcode & 0xffff8000) == 0x27bd8000)
515		    || ((opcode & 0xffff8000) == 0x67bd8000)) {
516			function_start = *pc - offset;
517			registers_on_stack = 1;
518			break;
519		}
520
521		/* lui gp, X */
522		if ((opcode & 0xffff8000) == 0x3c1c0000) {
523			/*
524			 * Function might start with this instruction
525			 * Keep an eye on "jr ra" and sp correction
526			 * with positive value further on
527			 */
528			function_start = *pc - offset;
529		}
530
531		if (function_start) {
532			/*
533			 * Stop looking further. Possible end of
534			 * function instruction: it means there is no
535			 * stack modifications, sp is unchanged
536			 */
537
538			/* [d]addiu sp,sp,X */
539			if (((opcode & 0xffff8000) == 0x27bd0000)
540			    || ((opcode & 0xffff8000) == 0x67bd0000))
541				break;
542
543			if (opcode == 0x03e00008)
544				break;
545		}
546
547		offset += sizeof(int);
548	}
549
550	if (!function_start)
551		return (-1);
552
553	if (registers_on_stack) {
554		offset = 0;
555		while ((offset < MAX_PROLOGUE_SIZE)
556		    && ((function_start + offset) < *pc)) {
557			i.word =
558			    dtrace_fuword32((void *)(vm_offset_t)(function_start + offset));
559			switch (i.JType.op) {
560			case OP_SW:
561				/* look for saved registers on the stack */
562				if (i.IType.rs != 29)
563					break;
564				/* only restore the first one */
565				if (mask & (1 << i.IType.rt))
566					break;
567				mask |= (1 << i.IType.rt);
568				if (i.IType.rt == 31)
569					*ra = dtrace_fuword32((void *)(vm_offset_t)(*sp + (short)i.IType.imm));
570				break;
571
572			case OP_SD:
573				/* look for saved registers on the stack */
574				if (i.IType.rs != 29)
575					break;
576				/* only restore the first one */
577				if (mask & (1 << i.IType.rt))
578					break;
579				mask |= (1 << i.IType.rt);
580				/* ra */
581				if (i.IType.rt == 31)
582					*ra = dtrace_fuword64((void *)(vm_offset_t)(*sp + (short)i.IType.imm));
583			break;
584
585			case OP_ADDI:
586			case OP_ADDIU:
587			case OP_DADDI:
588			case OP_DADDIU:
589				/* look for stack pointer adjustment */
590				if (i.IType.rs != 29 || i.IType.rt != 29)
591					break;
592				stksize = -((short)i.IType.imm);
593			}
594
595			offset += sizeof(int);
596		}
597	}
598
599	/*
600	 * We reached the end of backtrace
601	 */
602	if (*pc == *ra)
603		return (-1);
604
605	*pc = *ra;
606	*sp += stksize;
607
608	return (0);
609}
610
611static int
612dtrace_copycheck(uintptr_t uaddr, uintptr_t kaddr, size_t size)
613{
614
615	if (uaddr + size > VM_MAXUSER_ADDRESS || uaddr + size < uaddr) {
616		DTRACE_CPUFLAG_SET(CPU_DTRACE_BADADDR);
617		cpu_core[curcpu].cpuc_dtrace_illval = uaddr;
618		return (0);
619	}
620
621	return (1);
622}
623
624void
625dtrace_copyin(uintptr_t uaddr, uintptr_t kaddr, size_t size,
626    volatile uint16_t *flags)
627{
628	if (dtrace_copycheck(uaddr, kaddr, size))
629		dtrace_copy(uaddr, kaddr, size);
630}
631
632void
633dtrace_copyout(uintptr_t kaddr, uintptr_t uaddr, size_t size,
634    volatile uint16_t *flags)
635{
636	if (dtrace_copycheck(uaddr, kaddr, size))
637		dtrace_copy(kaddr, uaddr, size);
638}
639
640void
641dtrace_copyinstr(uintptr_t uaddr, uintptr_t kaddr, size_t size,
642    volatile uint16_t *flags)
643{
644	if (dtrace_copycheck(uaddr, kaddr, size))
645		dtrace_copystr(uaddr, kaddr, size, flags);
646}
647
648void
649dtrace_copyoutstr(uintptr_t kaddr, uintptr_t uaddr, size_t size,
650    volatile uint16_t *flags)
651{
652	if (dtrace_copycheck(uaddr, kaddr, size))
653		dtrace_copystr(kaddr, uaddr, size, flags);
654}
655
656uint8_t
657dtrace_fuword8(void *uaddr)
658{
659	if ((uintptr_t)uaddr > VM_MAXUSER_ADDRESS) {
660		DTRACE_CPUFLAG_SET(CPU_DTRACE_BADADDR);
661		cpu_core[curcpu].cpuc_dtrace_illval = (uintptr_t)uaddr;
662		return (0);
663	}
664	return (dtrace_fuword8_nocheck(uaddr));
665}
666
667uint16_t
668dtrace_fuword16(void *uaddr)
669{
670	if ((uintptr_t)uaddr > VM_MAXUSER_ADDRESS) {
671		DTRACE_CPUFLAG_SET(CPU_DTRACE_BADADDR);
672		cpu_core[curcpu].cpuc_dtrace_illval = (uintptr_t)uaddr;
673		return (0);
674	}
675	return (dtrace_fuword16_nocheck(uaddr));
676}
677
678uint32_t
679dtrace_fuword32(void *uaddr)
680{
681	if ((uintptr_t)uaddr > VM_MAXUSER_ADDRESS) {
682		DTRACE_CPUFLAG_SET(CPU_DTRACE_BADADDR);
683		cpu_core[curcpu].cpuc_dtrace_illval = (uintptr_t)uaddr;
684		return (0);
685	}
686	return (dtrace_fuword32_nocheck(uaddr));
687}
688
689uint64_t
690dtrace_fuword64(void *uaddr)
691{
692	if ((uintptr_t)uaddr > VM_MAXUSER_ADDRESS) {
693		DTRACE_CPUFLAG_SET(CPU_DTRACE_BADADDR);
694		cpu_core[curcpu].cpuc_dtrace_illval = (uintptr_t)uaddr;
695		return (0);
696	}
697	return (dtrace_fuword64_nocheck(uaddr));
698}
699