xref: /linux/arch/powerpc/lib/sstep.c (revision cf87c3f6b64791ce5d4c7e591c915065d31a162d)
1 /*
2  * Single-step support.
3  *
4  * Copyright (C) 2004 Paul Mackerras <paulus@au.ibm.com>, IBM
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * as published by the Free Software Foundation; either version
9  * 2 of the License, or (at your option) any later version.
10  */
11 #include <linux/kernel.h>
12 #include <linux/kprobes.h>
13 #include <linux/ptrace.h>
14 #include <linux/prefetch.h>
15 #include <asm/sstep.h>
16 #include <asm/processor.h>
17 #include <asm/uaccess.h>
18 #include <asm/cputable.h>
19 
20 extern char system_call_common[];
21 
22 #ifdef CONFIG_PPC64
23 /* Bits in SRR1 that are copied from MSR */
24 #define MSR_MASK	0xffffffff87c0ffffUL
25 #else
26 #define MSR_MASK	0x87c0ffff
27 #endif
28 
29 /* Bits in XER */
30 #define XER_SO		0x80000000U
31 #define XER_OV		0x40000000U
32 #define XER_CA		0x20000000U
33 
34 #ifdef CONFIG_PPC_FPU
35 /*
36  * Functions in ldstfp.S
37  */
38 extern int do_lfs(int rn, unsigned long ea);
39 extern int do_lfd(int rn, unsigned long ea);
40 extern int do_stfs(int rn, unsigned long ea);
41 extern int do_stfd(int rn, unsigned long ea);
42 extern int do_lvx(int rn, unsigned long ea);
43 extern int do_stvx(int rn, unsigned long ea);
44 extern int do_lxvd2x(int rn, unsigned long ea);
45 extern int do_stxvd2x(int rn, unsigned long ea);
46 #endif
47 
48 /*
49  * Emulate the truncation of 64 bit values in 32-bit mode.
50  */
51 static unsigned long truncate_if_32bit(unsigned long msr, unsigned long val)
52 {
53 #ifdef __powerpc64__
54 	if ((msr & MSR_64BIT) == 0)
55 		val &= 0xffffffffUL;
56 #endif
57 	return val;
58 }
59 
60 /*
61  * Determine whether a conditional branch instruction would branch.
62  */
63 static int __kprobes branch_taken(unsigned int instr, struct pt_regs *regs)
64 {
65 	unsigned int bo = (instr >> 21) & 0x1f;
66 	unsigned int bi;
67 
68 	if ((bo & 4) == 0) {
69 		/* decrement counter */
70 		--regs->ctr;
71 		if (((bo >> 1) & 1) ^ (regs->ctr == 0))
72 			return 0;
73 	}
74 	if ((bo & 0x10) == 0) {
75 		/* check bit from CR */
76 		bi = (instr >> 16) & 0x1f;
77 		if (((regs->ccr >> (31 - bi)) & 1) != ((bo >> 3) & 1))
78 			return 0;
79 	}
80 	return 1;
81 }
82 
83 
84 static long __kprobes address_ok(struct pt_regs *regs, unsigned long ea, int nb)
85 {
86 	if (!user_mode(regs))
87 		return 1;
88 	return __access_ok(ea, nb, USER_DS);
89 }
90 
91 /*
92  * Calculate effective address for a D-form instruction
93  */
94 static unsigned long __kprobes dform_ea(unsigned int instr, struct pt_regs *regs)
95 {
96 	int ra;
97 	unsigned long ea;
98 
99 	ra = (instr >> 16) & 0x1f;
100 	ea = (signed short) instr;		/* sign-extend */
101 	if (ra)
102 		ea += regs->gpr[ra];
103 
104 	return truncate_if_32bit(regs->msr, ea);
105 }
106 
107 #ifdef __powerpc64__
108 /*
109  * Calculate effective address for a DS-form instruction
110  */
111 static unsigned long __kprobes dsform_ea(unsigned int instr, struct pt_regs *regs)
112 {
113 	int ra;
114 	unsigned long ea;
115 
116 	ra = (instr >> 16) & 0x1f;
117 	ea = (signed short) (instr & ~3);	/* sign-extend */
118 	if (ra)
119 		ea += regs->gpr[ra];
120 
121 	return truncate_if_32bit(regs->msr, ea);
122 }
123 #endif /* __powerpc64 */
124 
125 /*
126  * Calculate effective address for an X-form instruction
127  */
128 static unsigned long __kprobes xform_ea(unsigned int instr,
129 					struct pt_regs *regs)
130 {
131 	int ra, rb;
132 	unsigned long ea;
133 
134 	ra = (instr >> 16) & 0x1f;
135 	rb = (instr >> 11) & 0x1f;
136 	ea = regs->gpr[rb];
137 	if (ra)
138 		ea += regs->gpr[ra];
139 
140 	return truncate_if_32bit(regs->msr, ea);
141 }
142 
143 /*
144  * Return the largest power of 2, not greater than sizeof(unsigned long),
145  * such that x is a multiple of it.
146  */
147 static inline unsigned long max_align(unsigned long x)
148 {
149 	x |= sizeof(unsigned long);
150 	return x & -x;		/* isolates rightmost bit */
151 }
152 
153 
154 static inline unsigned long byterev_2(unsigned long x)
155 {
156 	return ((x >> 8) & 0xff) | ((x & 0xff) << 8);
157 }
158 
159 static inline unsigned long byterev_4(unsigned long x)
160 {
161 	return ((x >> 24) & 0xff) | ((x >> 8) & 0xff00) |
162 		((x & 0xff00) << 8) | ((x & 0xff) << 24);
163 }
164 
165 #ifdef __powerpc64__
166 static inline unsigned long byterev_8(unsigned long x)
167 {
168 	return (byterev_4(x) << 32) | byterev_4(x >> 32);
169 }
170 #endif
171 
172 static int __kprobes read_mem_aligned(unsigned long *dest, unsigned long ea,
173 				      int nb)
174 {
175 	int err = 0;
176 	unsigned long x = 0;
177 
178 	switch (nb) {
179 	case 1:
180 		err = __get_user(x, (unsigned char __user *) ea);
181 		break;
182 	case 2:
183 		err = __get_user(x, (unsigned short __user *) ea);
184 		break;
185 	case 4:
186 		err = __get_user(x, (unsigned int __user *) ea);
187 		break;
188 #ifdef __powerpc64__
189 	case 8:
190 		err = __get_user(x, (unsigned long __user *) ea);
191 		break;
192 #endif
193 	}
194 	if (!err)
195 		*dest = x;
196 	return err;
197 }
198 
199 static int __kprobes read_mem_unaligned(unsigned long *dest, unsigned long ea,
200 					int nb, struct pt_regs *regs)
201 {
202 	int err;
203 	unsigned long x, b, c;
204 #ifdef __LITTLE_ENDIAN__
205 	int len = nb; /* save a copy of the length for byte reversal */
206 #endif
207 
208 	/* unaligned, do this in pieces */
209 	x = 0;
210 	for (; nb > 0; nb -= c) {
211 #ifdef __LITTLE_ENDIAN__
212 		c = 1;
213 #endif
214 #ifdef __BIG_ENDIAN__
215 		c = max_align(ea);
216 #endif
217 		if (c > nb)
218 			c = max_align(nb);
219 		err = read_mem_aligned(&b, ea, c);
220 		if (err)
221 			return err;
222 		x = (x << (8 * c)) + b;
223 		ea += c;
224 	}
225 #ifdef __LITTLE_ENDIAN__
226 	switch (len) {
227 	case 2:
228 		*dest = byterev_2(x);
229 		break;
230 	case 4:
231 		*dest = byterev_4(x);
232 		break;
233 #ifdef __powerpc64__
234 	case 8:
235 		*dest = byterev_8(x);
236 		break;
237 #endif
238 	}
239 #endif
240 #ifdef __BIG_ENDIAN__
241 	*dest = x;
242 #endif
243 	return 0;
244 }
245 
246 /*
247  * Read memory at address ea for nb bytes, return 0 for success
248  * or -EFAULT if an error occurred.
249  */
250 static int __kprobes read_mem(unsigned long *dest, unsigned long ea, int nb,
251 			      struct pt_regs *regs)
252 {
253 	if (!address_ok(regs, ea, nb))
254 		return -EFAULT;
255 	if ((ea & (nb - 1)) == 0)
256 		return read_mem_aligned(dest, ea, nb);
257 	return read_mem_unaligned(dest, ea, nb, regs);
258 }
259 
260 static int __kprobes write_mem_aligned(unsigned long val, unsigned long ea,
261 				       int nb)
262 {
263 	int err = 0;
264 
265 	switch (nb) {
266 	case 1:
267 		err = __put_user(val, (unsigned char __user *) ea);
268 		break;
269 	case 2:
270 		err = __put_user(val, (unsigned short __user *) ea);
271 		break;
272 	case 4:
273 		err = __put_user(val, (unsigned int __user *) ea);
274 		break;
275 #ifdef __powerpc64__
276 	case 8:
277 		err = __put_user(val, (unsigned long __user *) ea);
278 		break;
279 #endif
280 	}
281 	return err;
282 }
283 
284 static int __kprobes write_mem_unaligned(unsigned long val, unsigned long ea,
285 					 int nb, struct pt_regs *regs)
286 {
287 	int err;
288 	unsigned long c;
289 
290 #ifdef __LITTLE_ENDIAN__
291 	switch (nb) {
292 	case 2:
293 		val = byterev_2(val);
294 		break;
295 	case 4:
296 		val = byterev_4(val);
297 		break;
298 #ifdef __powerpc64__
299 	case 8:
300 		val = byterev_8(val);
301 		break;
302 #endif
303 	}
304 #endif
305 	/* unaligned or little-endian, do this in pieces */
306 	for (; nb > 0; nb -= c) {
307 #ifdef __LITTLE_ENDIAN__
308 		c = 1;
309 #endif
310 #ifdef __BIG_ENDIAN__
311 		c = max_align(ea);
312 #endif
313 		if (c > nb)
314 			c = max_align(nb);
315 		err = write_mem_aligned(val >> (nb - c) * 8, ea, c);
316 		if (err)
317 			return err;
318 		ea += c;
319 	}
320 	return 0;
321 }
322 
323 /*
324  * Write memory at address ea for nb bytes, return 0 for success
325  * or -EFAULT if an error occurred.
326  */
327 static int __kprobes write_mem(unsigned long val, unsigned long ea, int nb,
328 			       struct pt_regs *regs)
329 {
330 	if (!address_ok(regs, ea, nb))
331 		return -EFAULT;
332 	if ((ea & (nb - 1)) == 0)
333 		return write_mem_aligned(val, ea, nb);
334 	return write_mem_unaligned(val, ea, nb, regs);
335 }
336 
337 #ifdef CONFIG_PPC_FPU
338 /*
339  * Check the address and alignment, and call func to do the actual
340  * load or store.
341  */
342 static int __kprobes do_fp_load(int rn, int (*func)(int, unsigned long),
343 				unsigned long ea, int nb,
344 				struct pt_regs *regs)
345 {
346 	int err;
347 	union {
348 		double dbl;
349 		unsigned long ul[2];
350 		struct {
351 #ifdef __BIG_ENDIAN__
352 			unsigned _pad_;
353 			unsigned word;
354 #endif
355 #ifdef __LITTLE_ENDIAN__
356 			unsigned word;
357 			unsigned _pad_;
358 #endif
359 		} single;
360 	} data;
361 	unsigned long ptr;
362 
363 	if (!address_ok(regs, ea, nb))
364 		return -EFAULT;
365 	if ((ea & 3) == 0)
366 		return (*func)(rn, ea);
367 	ptr = (unsigned long) &data.ul;
368 	if (sizeof(unsigned long) == 8 || nb == 4) {
369 		err = read_mem_unaligned(&data.ul[0], ea, nb, regs);
370 		if (nb == 4)
371 			ptr = (unsigned long)&(data.single.word);
372 	} else {
373 		/* reading a double on 32-bit */
374 		err = read_mem_unaligned(&data.ul[0], ea, 4, regs);
375 		if (!err)
376 			err = read_mem_unaligned(&data.ul[1], ea + 4, 4, regs);
377 	}
378 	if (err)
379 		return err;
380 	return (*func)(rn, ptr);
381 }
382 
383 static int __kprobes do_fp_store(int rn, int (*func)(int, unsigned long),
384 				 unsigned long ea, int nb,
385 				 struct pt_regs *regs)
386 {
387 	int err;
388 	union {
389 		double dbl;
390 		unsigned long ul[2];
391 		struct {
392 #ifdef __BIG_ENDIAN__
393 			unsigned _pad_;
394 			unsigned word;
395 #endif
396 #ifdef __LITTLE_ENDIAN__
397 			unsigned word;
398 			unsigned _pad_;
399 #endif
400 		} single;
401 	} data;
402 	unsigned long ptr;
403 
404 	if (!address_ok(regs, ea, nb))
405 		return -EFAULT;
406 	if ((ea & 3) == 0)
407 		return (*func)(rn, ea);
408 	ptr = (unsigned long) &data.ul[0];
409 	if (sizeof(unsigned long) == 8 || nb == 4) {
410 		if (nb == 4)
411 			ptr = (unsigned long)&(data.single.word);
412 		err = (*func)(rn, ptr);
413 		if (err)
414 			return err;
415 		err = write_mem_unaligned(data.ul[0], ea, nb, regs);
416 	} else {
417 		/* writing a double on 32-bit */
418 		err = (*func)(rn, ptr);
419 		if (err)
420 			return err;
421 		err = write_mem_unaligned(data.ul[0], ea, 4, regs);
422 		if (!err)
423 			err = write_mem_unaligned(data.ul[1], ea + 4, 4, regs);
424 	}
425 	return err;
426 }
427 #endif
428 
429 #ifdef CONFIG_ALTIVEC
430 /* For Altivec/VMX, no need to worry about alignment */
431 static int __kprobes do_vec_load(int rn, int (*func)(int, unsigned long),
432 				 unsigned long ea, struct pt_regs *regs)
433 {
434 	if (!address_ok(regs, ea & ~0xfUL, 16))
435 		return -EFAULT;
436 	return (*func)(rn, ea);
437 }
438 
439 static int __kprobes do_vec_store(int rn, int (*func)(int, unsigned long),
440 				  unsigned long ea, struct pt_regs *regs)
441 {
442 	if (!address_ok(regs, ea & ~0xfUL, 16))
443 		return -EFAULT;
444 	return (*func)(rn, ea);
445 }
446 #endif /* CONFIG_ALTIVEC */
447 
448 #ifdef CONFIG_VSX
449 static int __kprobes do_vsx_load(int rn, int (*func)(int, unsigned long),
450 				 unsigned long ea, struct pt_regs *regs)
451 {
452 	int err;
453 	unsigned long val[2];
454 
455 	if (!address_ok(regs, ea, 16))
456 		return -EFAULT;
457 	if ((ea & 3) == 0)
458 		return (*func)(rn, ea);
459 	err = read_mem_unaligned(&val[0], ea, 8, regs);
460 	if (!err)
461 		err = read_mem_unaligned(&val[1], ea + 8, 8, regs);
462 	if (!err)
463 		err = (*func)(rn, (unsigned long) &val[0]);
464 	return err;
465 }
466 
467 static int __kprobes do_vsx_store(int rn, int (*func)(int, unsigned long),
468 				 unsigned long ea, struct pt_regs *regs)
469 {
470 	int err;
471 	unsigned long val[2];
472 
473 	if (!address_ok(regs, ea, 16))
474 		return -EFAULT;
475 	if ((ea & 3) == 0)
476 		return (*func)(rn, ea);
477 	err = (*func)(rn, (unsigned long) &val[0]);
478 	if (err)
479 		return err;
480 	err = write_mem_unaligned(val[0], ea, 8, regs);
481 	if (!err)
482 		err = write_mem_unaligned(val[1], ea + 8, 8, regs);
483 	return err;
484 }
485 #endif /* CONFIG_VSX */
486 
487 #define __put_user_asmx(x, addr, err, op, cr)		\
488 	__asm__ __volatile__(				\
489 		"1:	" op " %2,0,%3\n"		\
490 		"	mfcr	%1\n"			\
491 		"2:\n"					\
492 		".section .fixup,\"ax\"\n"		\
493 		"3:	li	%0,%4\n"		\
494 		"	b	2b\n"			\
495 		".previous\n"				\
496 		".section __ex_table,\"a\"\n"		\
497 			PPC_LONG_ALIGN "\n"		\
498 			PPC_LONG "1b,3b\n"		\
499 		".previous"				\
500 		: "=r" (err), "=r" (cr)			\
501 		: "r" (x), "r" (addr), "i" (-EFAULT), "0" (err))
502 
503 #define __get_user_asmx(x, addr, err, op)		\
504 	__asm__ __volatile__(				\
505 		"1:	"op" %1,0,%2\n"			\
506 		"2:\n"					\
507 		".section .fixup,\"ax\"\n"		\
508 		"3:	li	%0,%3\n"		\
509 		"	b	2b\n"			\
510 		".previous\n"				\
511 		".section __ex_table,\"a\"\n"		\
512 			PPC_LONG_ALIGN "\n"		\
513 			PPC_LONG "1b,3b\n"		\
514 		".previous"				\
515 		: "=r" (err), "=r" (x)			\
516 		: "r" (addr), "i" (-EFAULT), "0" (err))
517 
518 #define __cacheop_user_asmx(addr, err, op)		\
519 	__asm__ __volatile__(				\
520 		"1:	"op" 0,%1\n"			\
521 		"2:\n"					\
522 		".section .fixup,\"ax\"\n"		\
523 		"3:	li	%0,%3\n"		\
524 		"	b	2b\n"			\
525 		".previous\n"				\
526 		".section __ex_table,\"a\"\n"		\
527 			PPC_LONG_ALIGN "\n"		\
528 			PPC_LONG "1b,3b\n"		\
529 		".previous"				\
530 		: "=r" (err)				\
531 		: "r" (addr), "i" (-EFAULT), "0" (err))
532 
533 static void __kprobes set_cr0(struct pt_regs *regs, int rd)
534 {
535 	long val = regs->gpr[rd];
536 
537 	regs->ccr = (regs->ccr & 0x0fffffff) | ((regs->xer >> 3) & 0x10000000);
538 #ifdef __powerpc64__
539 	if (!(regs->msr & MSR_64BIT))
540 		val = (int) val;
541 #endif
542 	if (val < 0)
543 		regs->ccr |= 0x80000000;
544 	else if (val > 0)
545 		regs->ccr |= 0x40000000;
546 	else
547 		regs->ccr |= 0x20000000;
548 }
549 
550 static void __kprobes add_with_carry(struct pt_regs *regs, int rd,
551 				     unsigned long val1, unsigned long val2,
552 				     unsigned long carry_in)
553 {
554 	unsigned long val = val1 + val2;
555 
556 	if (carry_in)
557 		++val;
558 	regs->gpr[rd] = val;
559 #ifdef __powerpc64__
560 	if (!(regs->msr & MSR_64BIT)) {
561 		val = (unsigned int) val;
562 		val1 = (unsigned int) val1;
563 	}
564 #endif
565 	if (val < val1 || (carry_in && val == val1))
566 		regs->xer |= XER_CA;
567 	else
568 		regs->xer &= ~XER_CA;
569 }
570 
571 static void __kprobes do_cmp_signed(struct pt_regs *regs, long v1, long v2,
572 				    int crfld)
573 {
574 	unsigned int crval, shift;
575 
576 	crval = (regs->xer >> 31) & 1;		/* get SO bit */
577 	if (v1 < v2)
578 		crval |= 8;
579 	else if (v1 > v2)
580 		crval |= 4;
581 	else
582 		crval |= 2;
583 	shift = (7 - crfld) * 4;
584 	regs->ccr = (regs->ccr & ~(0xf << shift)) | (crval << shift);
585 }
586 
587 static void __kprobes do_cmp_unsigned(struct pt_regs *regs, unsigned long v1,
588 				      unsigned long v2, int crfld)
589 {
590 	unsigned int crval, shift;
591 
592 	crval = (regs->xer >> 31) & 1;		/* get SO bit */
593 	if (v1 < v2)
594 		crval |= 8;
595 	else if (v1 > v2)
596 		crval |= 4;
597 	else
598 		crval |= 2;
599 	shift = (7 - crfld) * 4;
600 	regs->ccr = (regs->ccr & ~(0xf << shift)) | (crval << shift);
601 }
602 
603 static int __kprobes trap_compare(long v1, long v2)
604 {
605 	int ret = 0;
606 
607 	if (v1 < v2)
608 		ret |= 0x10;
609 	else if (v1 > v2)
610 		ret |= 0x08;
611 	else
612 		ret |= 0x04;
613 	if ((unsigned long)v1 < (unsigned long)v2)
614 		ret |= 0x02;
615 	else if ((unsigned long)v1 > (unsigned long)v2)
616 		ret |= 0x01;
617 	return ret;
618 }
619 
620 /*
621  * Elements of 32-bit rotate and mask instructions.
622  */
623 #define MASK32(mb, me)	((0xffffffffUL >> (mb)) + \
624 			 ((signed long)-0x80000000L >> (me)) + ((me) >= (mb)))
625 #ifdef __powerpc64__
626 #define MASK64_L(mb)	(~0UL >> (mb))
627 #define MASK64_R(me)	((signed long)-0x8000000000000000L >> (me))
628 #define MASK64(mb, me)	(MASK64_L(mb) + MASK64_R(me) + ((me) >= (mb)))
629 #define DATA32(x)	(((x) & 0xffffffffUL) | (((x) & 0xffffffffUL) << 32))
630 #else
631 #define DATA32(x)	(x)
632 #endif
633 #define ROTATE(x, n)	((n) ? (((x) << (n)) | ((x) >> (8 * sizeof(long) - (n)))) : (x))
634 
635 /*
636  * Decode an instruction, and execute it if that can be done just by
637  * modifying *regs (i.e. integer arithmetic and logical instructions,
638  * branches, and barrier instructions).
639  * Returns 1 if the instruction has been executed, or 0 if not.
640  * Sets *op to indicate what the instruction does.
641  */
642 int __kprobes analyse_instr(struct instruction_op *op, struct pt_regs *regs,
643 			    unsigned int instr)
644 {
645 	unsigned int opcode, ra, rb, rd, spr, u;
646 	unsigned long int imm;
647 	unsigned long int val, val2;
648 	unsigned int mb, me, sh;
649 	long ival;
650 
651 	op->type = COMPUTE;
652 
653 	opcode = instr >> 26;
654 	switch (opcode) {
655 	case 16:	/* bc */
656 		op->type = BRANCH;
657 		imm = (signed short)(instr & 0xfffc);
658 		if ((instr & 2) == 0)
659 			imm += regs->nip;
660 		regs->nip += 4;
661 		regs->nip = truncate_if_32bit(regs->msr, regs->nip);
662 		if (instr & 1)
663 			regs->link = regs->nip;
664 		if (branch_taken(instr, regs))
665 			regs->nip = truncate_if_32bit(regs->msr, imm);
666 		return 1;
667 #ifdef CONFIG_PPC64
668 	case 17:	/* sc */
669 		if ((instr & 0xfe2) == 2)
670 			op->type = SYSCALL;
671 		else
672 			op->type = UNKNOWN;
673 		return 0;
674 #endif
675 	case 18:	/* b */
676 		op->type = BRANCH;
677 		imm = instr & 0x03fffffc;
678 		if (imm & 0x02000000)
679 			imm -= 0x04000000;
680 		if ((instr & 2) == 0)
681 			imm += regs->nip;
682 		if (instr & 1)
683 			regs->link = truncate_if_32bit(regs->msr, regs->nip + 4);
684 		imm = truncate_if_32bit(regs->msr, imm);
685 		regs->nip = imm;
686 		return 1;
687 	case 19:
688 		switch ((instr >> 1) & 0x3ff) {
689 		case 0:		/* mcrf */
690 			rd = (instr >> 21) & 0x1c;
691 			ra = (instr >> 16) & 0x1c;
692 			val = (regs->ccr >> ra) & 0xf;
693 			regs->ccr = (regs->ccr & ~(0xfUL << rd)) | (val << rd);
694 			goto instr_done;
695 
696 		case 16:	/* bclr */
697 		case 528:	/* bcctr */
698 			op->type = BRANCH;
699 			imm = (instr & 0x400)? regs->ctr: regs->link;
700 			regs->nip = truncate_if_32bit(regs->msr, regs->nip + 4);
701 			imm = truncate_if_32bit(regs->msr, imm);
702 			if (instr & 1)
703 				regs->link = regs->nip;
704 			if (branch_taken(instr, regs))
705 				regs->nip = imm;
706 			return 1;
707 
708 		case 18:	/* rfid, scary */
709 			if (regs->msr & MSR_PR)
710 				goto priv;
711 			op->type = RFI;
712 			return 0;
713 
714 		case 150:	/* isync */
715 			op->type = BARRIER;
716 			isync();
717 			goto instr_done;
718 
719 		case 33:	/* crnor */
720 		case 129:	/* crandc */
721 		case 193:	/* crxor */
722 		case 225:	/* crnand */
723 		case 257:	/* crand */
724 		case 289:	/* creqv */
725 		case 417:	/* crorc */
726 		case 449:	/* cror */
727 			ra = (instr >> 16) & 0x1f;
728 			rb = (instr >> 11) & 0x1f;
729 			rd = (instr >> 21) & 0x1f;
730 			ra = (regs->ccr >> (31 - ra)) & 1;
731 			rb = (regs->ccr >> (31 - rb)) & 1;
732 			val = (instr >> (6 + ra * 2 + rb)) & 1;
733 			regs->ccr = (regs->ccr & ~(1UL << (31 - rd))) |
734 				(val << (31 - rd));
735 			goto instr_done;
736 		}
737 		break;
738 	case 31:
739 		switch ((instr >> 1) & 0x3ff) {
740 		case 598:	/* sync */
741 			op->type = BARRIER;
742 #ifdef __powerpc64__
743 			switch ((instr >> 21) & 3) {
744 			case 1:		/* lwsync */
745 				asm volatile("lwsync" : : : "memory");
746 				goto instr_done;
747 			case 2:		/* ptesync */
748 				asm volatile("ptesync" : : : "memory");
749 				goto instr_done;
750 			}
751 #endif
752 			mb();
753 			goto instr_done;
754 
755 		case 854:	/* eieio */
756 			op->type = BARRIER;
757 			eieio();
758 			goto instr_done;
759 		}
760 		break;
761 	}
762 
763 	/* Following cases refer to regs->gpr[], so we need all regs */
764 	if (!FULL_REGS(regs))
765 		return 0;
766 
767 	rd = (instr >> 21) & 0x1f;
768 	ra = (instr >> 16) & 0x1f;
769 	rb = (instr >> 11) & 0x1f;
770 
771 	switch (opcode) {
772 #ifdef __powerpc64__
773 	case 2:		/* tdi */
774 		if (rd & trap_compare(regs->gpr[ra], (short) instr))
775 			goto trap;
776 		goto instr_done;
777 #endif
778 	case 3:		/* twi */
779 		if (rd & trap_compare((int)regs->gpr[ra], (short) instr))
780 			goto trap;
781 		goto instr_done;
782 
783 	case 7:		/* mulli */
784 		regs->gpr[rd] = regs->gpr[ra] * (short) instr;
785 		goto instr_done;
786 
787 	case 8:		/* subfic */
788 		imm = (short) instr;
789 		add_with_carry(regs, rd, ~regs->gpr[ra], imm, 1);
790 		goto instr_done;
791 
792 	case 10:	/* cmpli */
793 		imm = (unsigned short) instr;
794 		val = regs->gpr[ra];
795 #ifdef __powerpc64__
796 		if ((rd & 1) == 0)
797 			val = (unsigned int) val;
798 #endif
799 		do_cmp_unsigned(regs, val, imm, rd >> 2);
800 		goto instr_done;
801 
802 	case 11:	/* cmpi */
803 		imm = (short) instr;
804 		val = regs->gpr[ra];
805 #ifdef __powerpc64__
806 		if ((rd & 1) == 0)
807 			val = (int) val;
808 #endif
809 		do_cmp_signed(regs, val, imm, rd >> 2);
810 		goto instr_done;
811 
812 	case 12:	/* addic */
813 		imm = (short) instr;
814 		add_with_carry(regs, rd, regs->gpr[ra], imm, 0);
815 		goto instr_done;
816 
817 	case 13:	/* addic. */
818 		imm = (short) instr;
819 		add_with_carry(regs, rd, regs->gpr[ra], imm, 0);
820 		set_cr0(regs, rd);
821 		goto instr_done;
822 
823 	case 14:	/* addi */
824 		imm = (short) instr;
825 		if (ra)
826 			imm += regs->gpr[ra];
827 		regs->gpr[rd] = imm;
828 		goto instr_done;
829 
830 	case 15:	/* addis */
831 		imm = ((short) instr) << 16;
832 		if (ra)
833 			imm += regs->gpr[ra];
834 		regs->gpr[rd] = imm;
835 		goto instr_done;
836 
837 	case 20:	/* rlwimi */
838 		mb = (instr >> 6) & 0x1f;
839 		me = (instr >> 1) & 0x1f;
840 		val = DATA32(regs->gpr[rd]);
841 		imm = MASK32(mb, me);
842 		regs->gpr[ra] = (regs->gpr[ra] & ~imm) | (ROTATE(val, rb) & imm);
843 		goto logical_done;
844 
845 	case 21:	/* rlwinm */
846 		mb = (instr >> 6) & 0x1f;
847 		me = (instr >> 1) & 0x1f;
848 		val = DATA32(regs->gpr[rd]);
849 		regs->gpr[ra] = ROTATE(val, rb) & MASK32(mb, me);
850 		goto logical_done;
851 
852 	case 23:	/* rlwnm */
853 		mb = (instr >> 6) & 0x1f;
854 		me = (instr >> 1) & 0x1f;
855 		rb = regs->gpr[rb] & 0x1f;
856 		val = DATA32(regs->gpr[rd]);
857 		regs->gpr[ra] = ROTATE(val, rb) & MASK32(mb, me);
858 		goto logical_done;
859 
860 	case 24:	/* ori */
861 		imm = (unsigned short) instr;
862 		regs->gpr[ra] = regs->gpr[rd] | imm;
863 		goto instr_done;
864 
865 	case 25:	/* oris */
866 		imm = (unsigned short) instr;
867 		regs->gpr[ra] = regs->gpr[rd] | (imm << 16);
868 		goto instr_done;
869 
870 	case 26:	/* xori */
871 		imm = (unsigned short) instr;
872 		regs->gpr[ra] = regs->gpr[rd] ^ imm;
873 		goto instr_done;
874 
875 	case 27:	/* xoris */
876 		imm = (unsigned short) instr;
877 		regs->gpr[ra] = regs->gpr[rd] ^ (imm << 16);
878 		goto instr_done;
879 
880 	case 28:	/* andi. */
881 		imm = (unsigned short) instr;
882 		regs->gpr[ra] = regs->gpr[rd] & imm;
883 		set_cr0(regs, ra);
884 		goto instr_done;
885 
886 	case 29:	/* andis. */
887 		imm = (unsigned short) instr;
888 		regs->gpr[ra] = regs->gpr[rd] & (imm << 16);
889 		set_cr0(regs, ra);
890 		goto instr_done;
891 
892 #ifdef __powerpc64__
893 	case 30:	/* rld* */
894 		mb = ((instr >> 6) & 0x1f) | (instr & 0x20);
895 		val = regs->gpr[rd];
896 		if ((instr & 0x10) == 0) {
897 			sh = rb | ((instr & 2) << 4);
898 			val = ROTATE(val, sh);
899 			switch ((instr >> 2) & 3) {
900 			case 0:		/* rldicl */
901 				regs->gpr[ra] = val & MASK64_L(mb);
902 				goto logical_done;
903 			case 1:		/* rldicr */
904 				regs->gpr[ra] = val & MASK64_R(mb);
905 				goto logical_done;
906 			case 2:		/* rldic */
907 				regs->gpr[ra] = val & MASK64(mb, 63 - sh);
908 				goto logical_done;
909 			case 3:		/* rldimi */
910 				imm = MASK64(mb, 63 - sh);
911 				regs->gpr[ra] = (regs->gpr[ra] & ~imm) |
912 					(val & imm);
913 				goto logical_done;
914 			}
915 		} else {
916 			sh = regs->gpr[rb] & 0x3f;
917 			val = ROTATE(val, sh);
918 			switch ((instr >> 1) & 7) {
919 			case 0:		/* rldcl */
920 				regs->gpr[ra] = val & MASK64_L(mb);
921 				goto logical_done;
922 			case 1:		/* rldcr */
923 				regs->gpr[ra] = val & MASK64_R(mb);
924 				goto logical_done;
925 			}
926 		}
927 #endif
928 
929 	case 31:
930 		switch ((instr >> 1) & 0x3ff) {
931 		case 4:		/* tw */
932 			if (rd == 0x1f ||
933 			    (rd & trap_compare((int)regs->gpr[ra],
934 					       (int)regs->gpr[rb])))
935 				goto trap;
936 			goto instr_done;
937 #ifdef __powerpc64__
938 		case 68:	/* td */
939 			if (rd & trap_compare(regs->gpr[ra], regs->gpr[rb]))
940 				goto trap;
941 			goto instr_done;
942 #endif
943 		case 83:	/* mfmsr */
944 			if (regs->msr & MSR_PR)
945 				goto priv;
946 			op->type = MFMSR;
947 			op->reg = rd;
948 			return 0;
949 		case 146:	/* mtmsr */
950 			if (regs->msr & MSR_PR)
951 				goto priv;
952 			op->type = MTMSR;
953 			op->reg = rd;
954 			op->val = 0xffffffff & ~(MSR_ME | MSR_LE);
955 			return 0;
956 #ifdef CONFIG_PPC64
957 		case 178:	/* mtmsrd */
958 			if (regs->msr & MSR_PR)
959 				goto priv;
960 			op->type = MTMSR;
961 			op->reg = rd;
962 			/* only MSR_EE and MSR_RI get changed if bit 15 set */
963 			/* mtmsrd doesn't change MSR_HV, MSR_ME or MSR_LE */
964 			imm = (instr & 0x10000)? 0x8002: 0xefffffffffffeffeUL;
965 			op->val = imm;
966 			return 0;
967 #endif
968 
969 		case 19:	/* mfcr */
970 			regs->gpr[rd] = regs->ccr;
971 			regs->gpr[rd] &= 0xffffffffUL;
972 			goto instr_done;
973 
974 		case 144:	/* mtcrf */
975 			imm = 0xf0000000UL;
976 			val = regs->gpr[rd];
977 			for (sh = 0; sh < 8; ++sh) {
978 				if (instr & (0x80000 >> sh))
979 					regs->ccr = (regs->ccr & ~imm) |
980 						(val & imm);
981 				imm >>= 4;
982 			}
983 			goto instr_done;
984 
985 		case 339:	/* mfspr */
986 			spr = ((instr >> 16) & 0x1f) | ((instr >> 6) & 0x3e0);
987 			switch (spr) {
988 			case SPRN_XER:	/* mfxer */
989 				regs->gpr[rd] = regs->xer;
990 				regs->gpr[rd] &= 0xffffffffUL;
991 				goto instr_done;
992 			case SPRN_LR:	/* mflr */
993 				regs->gpr[rd] = regs->link;
994 				goto instr_done;
995 			case SPRN_CTR:	/* mfctr */
996 				regs->gpr[rd] = regs->ctr;
997 				goto instr_done;
998 			default:
999 				op->type = MFSPR;
1000 				op->reg = rd;
1001 				op->spr = spr;
1002 				return 0;
1003 			}
1004 			break;
1005 
1006 		case 467:	/* mtspr */
1007 			spr = ((instr >> 16) & 0x1f) | ((instr >> 6) & 0x3e0);
1008 			switch (spr) {
1009 			case SPRN_XER:	/* mtxer */
1010 				regs->xer = (regs->gpr[rd] & 0xffffffffUL);
1011 				goto instr_done;
1012 			case SPRN_LR:	/* mtlr */
1013 				regs->link = regs->gpr[rd];
1014 				goto instr_done;
1015 			case SPRN_CTR:	/* mtctr */
1016 				regs->ctr = regs->gpr[rd];
1017 				goto instr_done;
1018 			default:
1019 				op->type = MTSPR;
1020 				op->val = regs->gpr[rd];
1021 				op->spr = spr;
1022 				return 0;
1023 			}
1024 			break;
1025 
1026 /*
1027  * Compare instructions
1028  */
1029 		case 0:	/* cmp */
1030 			val = regs->gpr[ra];
1031 			val2 = regs->gpr[rb];
1032 #ifdef __powerpc64__
1033 			if ((rd & 1) == 0) {
1034 				/* word (32-bit) compare */
1035 				val = (int) val;
1036 				val2 = (int) val2;
1037 			}
1038 #endif
1039 			do_cmp_signed(regs, val, val2, rd >> 2);
1040 			goto instr_done;
1041 
1042 		case 32:	/* cmpl */
1043 			val = regs->gpr[ra];
1044 			val2 = regs->gpr[rb];
1045 #ifdef __powerpc64__
1046 			if ((rd & 1) == 0) {
1047 				/* word (32-bit) compare */
1048 				val = (unsigned int) val;
1049 				val2 = (unsigned int) val2;
1050 			}
1051 #endif
1052 			do_cmp_unsigned(regs, val, val2, rd >> 2);
1053 			goto instr_done;
1054 
1055 /*
1056  * Arithmetic instructions
1057  */
1058 		case 8:	/* subfc */
1059 			add_with_carry(regs, rd, ~regs->gpr[ra],
1060 				       regs->gpr[rb], 1);
1061 			goto arith_done;
1062 #ifdef __powerpc64__
1063 		case 9:	/* mulhdu */
1064 			asm("mulhdu %0,%1,%2" : "=r" (regs->gpr[rd]) :
1065 			    "r" (regs->gpr[ra]), "r" (regs->gpr[rb]));
1066 			goto arith_done;
1067 #endif
1068 		case 10:	/* addc */
1069 			add_with_carry(regs, rd, regs->gpr[ra],
1070 				       regs->gpr[rb], 0);
1071 			goto arith_done;
1072 
1073 		case 11:	/* mulhwu */
1074 			asm("mulhwu %0,%1,%2" : "=r" (regs->gpr[rd]) :
1075 			    "r" (regs->gpr[ra]), "r" (regs->gpr[rb]));
1076 			goto arith_done;
1077 
1078 		case 40:	/* subf */
1079 			regs->gpr[rd] = regs->gpr[rb] - regs->gpr[ra];
1080 			goto arith_done;
1081 #ifdef __powerpc64__
1082 		case 73:	/* mulhd */
1083 			asm("mulhd %0,%1,%2" : "=r" (regs->gpr[rd]) :
1084 			    "r" (regs->gpr[ra]), "r" (regs->gpr[rb]));
1085 			goto arith_done;
1086 #endif
1087 		case 75:	/* mulhw */
1088 			asm("mulhw %0,%1,%2" : "=r" (regs->gpr[rd]) :
1089 			    "r" (regs->gpr[ra]), "r" (regs->gpr[rb]));
1090 			goto arith_done;
1091 
1092 		case 104:	/* neg */
1093 			regs->gpr[rd] = -regs->gpr[ra];
1094 			goto arith_done;
1095 
1096 		case 136:	/* subfe */
1097 			add_with_carry(regs, rd, ~regs->gpr[ra], regs->gpr[rb],
1098 				       regs->xer & XER_CA);
1099 			goto arith_done;
1100 
1101 		case 138:	/* adde */
1102 			add_with_carry(regs, rd, regs->gpr[ra], regs->gpr[rb],
1103 				       regs->xer & XER_CA);
1104 			goto arith_done;
1105 
1106 		case 200:	/* subfze */
1107 			add_with_carry(regs, rd, ~regs->gpr[ra], 0L,
1108 				       regs->xer & XER_CA);
1109 			goto arith_done;
1110 
1111 		case 202:	/* addze */
1112 			add_with_carry(regs, rd, regs->gpr[ra], 0L,
1113 				       regs->xer & XER_CA);
1114 			goto arith_done;
1115 
1116 		case 232:	/* subfme */
1117 			add_with_carry(regs, rd, ~regs->gpr[ra], -1L,
1118 				       regs->xer & XER_CA);
1119 			goto arith_done;
1120 #ifdef __powerpc64__
1121 		case 233:	/* mulld */
1122 			regs->gpr[rd] = regs->gpr[ra] * regs->gpr[rb];
1123 			goto arith_done;
1124 #endif
1125 		case 234:	/* addme */
1126 			add_with_carry(regs, rd, regs->gpr[ra], -1L,
1127 				       regs->xer & XER_CA);
1128 			goto arith_done;
1129 
1130 		case 235:	/* mullw */
1131 			regs->gpr[rd] = (unsigned int) regs->gpr[ra] *
1132 				(unsigned int) regs->gpr[rb];
1133 			goto arith_done;
1134 
1135 		case 266:	/* add */
1136 			regs->gpr[rd] = regs->gpr[ra] + regs->gpr[rb];
1137 			goto arith_done;
1138 #ifdef __powerpc64__
1139 		case 457:	/* divdu */
1140 			regs->gpr[rd] = regs->gpr[ra] / regs->gpr[rb];
1141 			goto arith_done;
1142 #endif
1143 		case 459:	/* divwu */
1144 			regs->gpr[rd] = (unsigned int) regs->gpr[ra] /
1145 				(unsigned int) regs->gpr[rb];
1146 			goto arith_done;
1147 #ifdef __powerpc64__
1148 		case 489:	/* divd */
1149 			regs->gpr[rd] = (long int) regs->gpr[ra] /
1150 				(long int) regs->gpr[rb];
1151 			goto arith_done;
1152 #endif
1153 		case 491:	/* divw */
1154 			regs->gpr[rd] = (int) regs->gpr[ra] /
1155 				(int) regs->gpr[rb];
1156 			goto arith_done;
1157 
1158 
1159 /*
1160  * Logical instructions
1161  */
1162 		case 26:	/* cntlzw */
1163 			asm("cntlzw %0,%1" : "=r" (regs->gpr[ra]) :
1164 			    "r" (regs->gpr[rd]));
1165 			goto logical_done;
1166 #ifdef __powerpc64__
1167 		case 58:	/* cntlzd */
1168 			asm("cntlzd %0,%1" : "=r" (regs->gpr[ra]) :
1169 			    "r" (regs->gpr[rd]));
1170 			goto logical_done;
1171 #endif
1172 		case 28:	/* and */
1173 			regs->gpr[ra] = regs->gpr[rd] & regs->gpr[rb];
1174 			goto logical_done;
1175 
1176 		case 60:	/* andc */
1177 			regs->gpr[ra] = regs->gpr[rd] & ~regs->gpr[rb];
1178 			goto logical_done;
1179 
1180 		case 124:	/* nor */
1181 			regs->gpr[ra] = ~(regs->gpr[rd] | regs->gpr[rb]);
1182 			goto logical_done;
1183 
1184 		case 284:	/* xor */
1185 			regs->gpr[ra] = ~(regs->gpr[rd] ^ regs->gpr[rb]);
1186 			goto logical_done;
1187 
1188 		case 316:	/* xor */
1189 			regs->gpr[ra] = regs->gpr[rd] ^ regs->gpr[rb];
1190 			goto logical_done;
1191 
1192 		case 412:	/* orc */
1193 			regs->gpr[ra] = regs->gpr[rd] | ~regs->gpr[rb];
1194 			goto logical_done;
1195 
1196 		case 444:	/* or */
1197 			regs->gpr[ra] = regs->gpr[rd] | regs->gpr[rb];
1198 			goto logical_done;
1199 
1200 		case 476:	/* nand */
1201 			regs->gpr[ra] = ~(regs->gpr[rd] & regs->gpr[rb]);
1202 			goto logical_done;
1203 
1204 		case 922:	/* extsh */
1205 			regs->gpr[ra] = (signed short) regs->gpr[rd];
1206 			goto logical_done;
1207 
1208 		case 954:	/* extsb */
1209 			regs->gpr[ra] = (signed char) regs->gpr[rd];
1210 			goto logical_done;
1211 #ifdef __powerpc64__
1212 		case 986:	/* extsw */
1213 			regs->gpr[ra] = (signed int) regs->gpr[rd];
1214 			goto logical_done;
1215 #endif
1216 
1217 /*
1218  * Shift instructions
1219  */
1220 		case 24:	/* slw */
1221 			sh = regs->gpr[rb] & 0x3f;
1222 			if (sh < 32)
1223 				regs->gpr[ra] = (regs->gpr[rd] << sh) & 0xffffffffUL;
1224 			else
1225 				regs->gpr[ra] = 0;
1226 			goto logical_done;
1227 
1228 		case 536:	/* srw */
1229 			sh = regs->gpr[rb] & 0x3f;
1230 			if (sh < 32)
1231 				regs->gpr[ra] = (regs->gpr[rd] & 0xffffffffUL) >> sh;
1232 			else
1233 				regs->gpr[ra] = 0;
1234 			goto logical_done;
1235 
1236 		case 792:	/* sraw */
1237 			sh = regs->gpr[rb] & 0x3f;
1238 			ival = (signed int) regs->gpr[rd];
1239 			regs->gpr[ra] = ival >> (sh < 32 ? sh : 31);
1240 			if (ival < 0 && (sh >= 32 || (ival & ((1ul << sh) - 1)) != 0))
1241 				regs->xer |= XER_CA;
1242 			else
1243 				regs->xer &= ~XER_CA;
1244 			goto logical_done;
1245 
1246 		case 824:	/* srawi */
1247 			sh = rb;
1248 			ival = (signed int) regs->gpr[rd];
1249 			regs->gpr[ra] = ival >> sh;
1250 			if (ival < 0 && (ival & ((1ul << sh) - 1)) != 0)
1251 				regs->xer |= XER_CA;
1252 			else
1253 				regs->xer &= ~XER_CA;
1254 			goto logical_done;
1255 
1256 #ifdef __powerpc64__
1257 		case 27:	/* sld */
1258 			sh = regs->gpr[rb] & 0x7f;
1259 			if (sh < 64)
1260 				regs->gpr[ra] = regs->gpr[rd] << sh;
1261 			else
1262 				regs->gpr[ra] = 0;
1263 			goto logical_done;
1264 
1265 		case 539:	/* srd */
1266 			sh = regs->gpr[rb] & 0x7f;
1267 			if (sh < 64)
1268 				regs->gpr[ra] = regs->gpr[rd] >> sh;
1269 			else
1270 				regs->gpr[ra] = 0;
1271 			goto logical_done;
1272 
1273 		case 794:	/* srad */
1274 			sh = regs->gpr[rb] & 0x7f;
1275 			ival = (signed long int) regs->gpr[rd];
1276 			regs->gpr[ra] = ival >> (sh < 64 ? sh : 63);
1277 			if (ival < 0 && (sh >= 64 || (ival & ((1ul << sh) - 1)) != 0))
1278 				regs->xer |= XER_CA;
1279 			else
1280 				regs->xer &= ~XER_CA;
1281 			goto logical_done;
1282 
1283 		case 826:	/* sradi with sh_5 = 0 */
1284 		case 827:	/* sradi with sh_5 = 1 */
1285 			sh = rb | ((instr & 2) << 4);
1286 			ival = (signed long int) regs->gpr[rd];
1287 			regs->gpr[ra] = ival >> sh;
1288 			if (ival < 0 && (ival & ((1ul << sh) - 1)) != 0)
1289 				regs->xer |= XER_CA;
1290 			else
1291 				regs->xer &= ~XER_CA;
1292 			goto logical_done;
1293 #endif /* __powerpc64__ */
1294 
1295 /*
1296  * Cache instructions
1297  */
1298 		case 54:	/* dcbst */
1299 			op->type = MKOP(CACHEOP, DCBST, 0);
1300 			op->ea = xform_ea(instr, regs);
1301 			return 0;
1302 
1303 		case 86:	/* dcbf */
1304 			op->type = MKOP(CACHEOP, DCBF, 0);
1305 			op->ea = xform_ea(instr, regs);
1306 			return 0;
1307 
1308 		case 246:	/* dcbtst */
1309 			op->type = MKOP(CACHEOP, DCBTST, 0);
1310 			op->ea = xform_ea(instr, regs);
1311 			op->reg = rd;
1312 			return 0;
1313 
1314 		case 278:	/* dcbt */
1315 			op->type = MKOP(CACHEOP, DCBTST, 0);
1316 			op->ea = xform_ea(instr, regs);
1317 			op->reg = rd;
1318 			return 0;
1319 
1320 		case 982:	/* icbi */
1321 			op->type = MKOP(CACHEOP, ICBI, 0);
1322 			op->ea = xform_ea(instr, regs);
1323 			return 0;
1324 		}
1325 		break;
1326 	}
1327 
1328 	/*
1329 	 * Loads and stores.
1330 	 */
1331 	op->type = UNKNOWN;
1332 	op->update_reg = ra;
1333 	op->reg = rd;
1334 	op->val = regs->gpr[rd];
1335 	u = (instr >> 20) & UPDATE;
1336 
1337 	switch (opcode) {
1338 	case 31:
1339 		u = instr & UPDATE;
1340 		op->ea = xform_ea(instr, regs);
1341 		switch ((instr >> 1) & 0x3ff) {
1342 		case 20:	/* lwarx */
1343 			op->type = MKOP(LARX, 0, 4);
1344 			break;
1345 
1346 		case 150:	/* stwcx. */
1347 			op->type = MKOP(STCX, 0, 4);
1348 			break;
1349 
1350 #ifdef __powerpc64__
1351 		case 84:	/* ldarx */
1352 			op->type = MKOP(LARX, 0, 8);
1353 			break;
1354 
1355 		case 214:	/* stdcx. */
1356 			op->type = MKOP(STCX, 0, 8);
1357 			break;
1358 
1359 		case 21:	/* ldx */
1360 		case 53:	/* ldux */
1361 			op->type = MKOP(LOAD, u, 8);
1362 			break;
1363 #endif
1364 
1365 		case 23:	/* lwzx */
1366 		case 55:	/* lwzux */
1367 			op->type = MKOP(LOAD, u, 4);
1368 			break;
1369 
1370 		case 87:	/* lbzx */
1371 		case 119:	/* lbzux */
1372 			op->type = MKOP(LOAD, u, 1);
1373 			break;
1374 
1375 #ifdef CONFIG_ALTIVEC
1376 		case 103:	/* lvx */
1377 		case 359:	/* lvxl */
1378 			if (!(regs->msr & MSR_VEC))
1379 				goto vecunavail;
1380 			op->type = MKOP(LOAD_VMX, 0, 16);
1381 			break;
1382 
1383 		case 231:	/* stvx */
1384 		case 487:	/* stvxl */
1385 			if (!(regs->msr & MSR_VEC))
1386 				goto vecunavail;
1387 			op->type = MKOP(STORE_VMX, 0, 16);
1388 			break;
1389 #endif /* CONFIG_ALTIVEC */
1390 
1391 #ifdef __powerpc64__
1392 		case 149:	/* stdx */
1393 		case 181:	/* stdux */
1394 			op->type = MKOP(STORE, u, 8);
1395 			break;
1396 #endif
1397 
1398 		case 151:	/* stwx */
1399 		case 183:	/* stwux */
1400 			op->type = MKOP(STORE, u, 4);
1401 			break;
1402 
1403 		case 215:	/* stbx */
1404 		case 247:	/* stbux */
1405 			op->type = MKOP(STORE, u, 1);
1406 			break;
1407 
1408 		case 279:	/* lhzx */
1409 		case 311:	/* lhzux */
1410 			op->type = MKOP(LOAD, u, 2);
1411 			break;
1412 
1413 #ifdef __powerpc64__
1414 		case 341:	/* lwax */
1415 		case 373:	/* lwaux */
1416 			op->type = MKOP(LOAD, SIGNEXT | u, 4);
1417 			break;
1418 #endif
1419 
1420 		case 343:	/* lhax */
1421 		case 375:	/* lhaux */
1422 			op->type = MKOP(LOAD, SIGNEXT | u, 2);
1423 			break;
1424 
1425 		case 407:	/* sthx */
1426 		case 439:	/* sthux */
1427 			op->type = MKOP(STORE, u, 2);
1428 			break;
1429 
1430 #ifdef __powerpc64__
1431 		case 532:	/* ldbrx */
1432 			op->type = MKOP(LOAD, BYTEREV, 8);
1433 			break;
1434 
1435 #endif
1436 
1437 		case 534:	/* lwbrx */
1438 			op->type = MKOP(LOAD, BYTEREV, 4);
1439 			break;
1440 
1441 #ifdef CONFIG_PPC_FPU
1442 		case 535:	/* lfsx */
1443 		case 567:	/* lfsux */
1444 			if (!(regs->msr & MSR_FP))
1445 				goto fpunavail;
1446 			op->type = MKOP(LOAD_FP, u, 4);
1447 			break;
1448 
1449 		case 599:	/* lfdx */
1450 		case 631:	/* lfdux */
1451 			if (!(regs->msr & MSR_FP))
1452 				goto fpunavail;
1453 			op->type = MKOP(LOAD_FP, u, 8);
1454 			break;
1455 
1456 		case 663:	/* stfsx */
1457 		case 695:	/* stfsux */
1458 			if (!(regs->msr & MSR_FP))
1459 				goto fpunavail;
1460 			op->type = MKOP(STORE_FP, u, 4);
1461 			break;
1462 
1463 		case 727:	/* stfdx */
1464 		case 759:	/* stfdux */
1465 			if (!(regs->msr & MSR_FP))
1466 				goto fpunavail;
1467 			op->type = MKOP(STORE_FP, u, 8);
1468 			break;
1469 #endif
1470 
1471 #ifdef __powerpc64__
1472 		case 660:	/* stdbrx */
1473 			op->type = MKOP(STORE, BYTEREV, 8);
1474 			op->val = byterev_8(regs->gpr[rd]);
1475 			break;
1476 
1477 #endif
1478 		case 662:	/* stwbrx */
1479 			op->type = MKOP(STORE, BYTEREV, 4);
1480 			op->val = byterev_4(regs->gpr[rd]);
1481 			break;
1482 
1483 		case 790:	/* lhbrx */
1484 			op->type = MKOP(LOAD, BYTEREV, 2);
1485 			break;
1486 
1487 		case 918:	/* sthbrx */
1488 			op->type = MKOP(STORE, BYTEREV, 2);
1489 			op->val = byterev_2(regs->gpr[rd]);
1490 			break;
1491 
1492 #ifdef CONFIG_VSX
1493 		case 844:	/* lxvd2x */
1494 		case 876:	/* lxvd2ux */
1495 			if (!(regs->msr & MSR_VSX))
1496 				goto vsxunavail;
1497 			op->reg = rd | ((instr & 1) << 5);
1498 			op->type = MKOP(LOAD_VSX, u, 16);
1499 			break;
1500 
1501 		case 972:	/* stxvd2x */
1502 		case 1004:	/* stxvd2ux */
1503 			if (!(regs->msr & MSR_VSX))
1504 				goto vsxunavail;
1505 			op->reg = rd | ((instr & 1) << 5);
1506 			op->type = MKOP(STORE_VSX, u, 16);
1507 			break;
1508 
1509 #endif /* CONFIG_VSX */
1510 		}
1511 		break;
1512 
1513 	case 32:	/* lwz */
1514 	case 33:	/* lwzu */
1515 		op->type = MKOP(LOAD, u, 4);
1516 		op->ea = dform_ea(instr, regs);
1517 		break;
1518 
1519 	case 34:	/* lbz */
1520 	case 35:	/* lbzu */
1521 		op->type = MKOP(LOAD, u, 1);
1522 		op->ea = dform_ea(instr, regs);
1523 		break;
1524 
1525 	case 36:	/* stw */
1526 	case 37:	/* stwu */
1527 		op->type = MKOP(STORE, u, 4);
1528 		op->ea = dform_ea(instr, regs);
1529 		break;
1530 
1531 	case 38:	/* stb */
1532 	case 39:	/* stbu */
1533 		op->type = MKOP(STORE, u, 1);
1534 		op->ea = dform_ea(instr, regs);
1535 		break;
1536 
1537 	case 40:	/* lhz */
1538 	case 41:	/* lhzu */
1539 		op->type = MKOP(LOAD, u, 2);
1540 		op->ea = dform_ea(instr, regs);
1541 		break;
1542 
1543 	case 42:	/* lha */
1544 	case 43:	/* lhau */
1545 		op->type = MKOP(LOAD, SIGNEXT | u, 2);
1546 		op->ea = dform_ea(instr, regs);
1547 		break;
1548 
1549 	case 44:	/* sth */
1550 	case 45:	/* sthu */
1551 		op->type = MKOP(STORE, u, 2);
1552 		op->ea = dform_ea(instr, regs);
1553 		break;
1554 
1555 	case 46:	/* lmw */
1556 		ra = (instr >> 16) & 0x1f;
1557 		if (ra >= rd)
1558 			break;		/* invalid form, ra in range to load */
1559 		op->type = MKOP(LOAD_MULTI, 0, 4);
1560 		op->ea = dform_ea(instr, regs);
1561 		break;
1562 
1563 	case 47:	/* stmw */
1564 		op->type = MKOP(STORE_MULTI, 0, 4);
1565 		op->ea = dform_ea(instr, regs);
1566 		break;
1567 
1568 #ifdef CONFIG_PPC_FPU
1569 	case 48:	/* lfs */
1570 	case 49:	/* lfsu */
1571 		if (!(regs->msr & MSR_FP))
1572 			goto fpunavail;
1573 		op->type = MKOP(LOAD_FP, u, 4);
1574 		op->ea = dform_ea(instr, regs);
1575 		break;
1576 
1577 	case 50:	/* lfd */
1578 	case 51:	/* lfdu */
1579 		if (!(regs->msr & MSR_FP))
1580 			goto fpunavail;
1581 		op->type = MKOP(LOAD_FP, u, 8);
1582 		op->ea = dform_ea(instr, regs);
1583 		break;
1584 
1585 	case 52:	/* stfs */
1586 	case 53:	/* stfsu */
1587 		if (!(regs->msr & MSR_FP))
1588 			goto fpunavail;
1589 		op->type = MKOP(STORE_FP, u, 4);
1590 		op->ea = dform_ea(instr, regs);
1591 		break;
1592 
1593 	case 54:	/* stfd */
1594 	case 55:	/* stfdu */
1595 		if (!(regs->msr & MSR_FP))
1596 			goto fpunavail;
1597 		op->type = MKOP(STORE_FP, u, 8);
1598 		op->ea = dform_ea(instr, regs);
1599 		break;
1600 #endif
1601 
1602 #ifdef __powerpc64__
1603 	case 58:	/* ld[u], lwa */
1604 		op->ea = dsform_ea(instr, regs);
1605 		switch (instr & 3) {
1606 		case 0:		/* ld */
1607 			op->type = MKOP(LOAD, 0, 8);
1608 			break;
1609 		case 1:		/* ldu */
1610 			op->type = MKOP(LOAD, UPDATE, 8);
1611 			break;
1612 		case 2:		/* lwa */
1613 			op->type = MKOP(LOAD, SIGNEXT, 4);
1614 			break;
1615 		}
1616 		break;
1617 
1618 	case 62:	/* std[u] */
1619 		op->ea = dsform_ea(instr, regs);
1620 		switch (instr & 3) {
1621 		case 0:		/* std */
1622 			op->type = MKOP(STORE, 0, 8);
1623 			break;
1624 		case 1:		/* stdu */
1625 			op->type = MKOP(STORE, UPDATE, 8);
1626 			break;
1627 		}
1628 		break;
1629 #endif /* __powerpc64__ */
1630 
1631 	}
1632 	return 0;
1633 
1634  logical_done:
1635 	if (instr & 1)
1636 		set_cr0(regs, ra);
1637 	goto instr_done;
1638 
1639  arith_done:
1640 	if (instr & 1)
1641 		set_cr0(regs, rd);
1642 
1643  instr_done:
1644 	regs->nip = truncate_if_32bit(regs->msr, regs->nip + 4);
1645 	return 1;
1646 
1647  priv:
1648 	op->type = INTERRUPT | 0x700;
1649 	op->val = SRR1_PROGPRIV;
1650 	return 0;
1651 
1652  trap:
1653 	op->type = INTERRUPT | 0x700;
1654 	op->val = SRR1_PROGTRAP;
1655 	return 0;
1656 
1657 #ifdef CONFIG_PPC_FPU
1658  fpunavail:
1659 	op->type = INTERRUPT | 0x800;
1660 	return 0;
1661 #endif
1662 
1663 #ifdef CONFIG_ALTIVEC
1664  vecunavail:
1665 	op->type = INTERRUPT | 0xf20;
1666 	return 0;
1667 #endif
1668 
1669 #ifdef CONFIG_VSX
1670  vsxunavail:
1671 	op->type = INTERRUPT | 0xf40;
1672 	return 0;
1673 #endif
1674 }
1675 EXPORT_SYMBOL_GPL(analyse_instr);
1676 
1677 /*
1678  * For PPC32 we always use stwu with r1 to change the stack pointer.
1679  * So this emulated store may corrupt the exception frame, now we
1680  * have to provide the exception frame trampoline, which is pushed
1681  * below the kprobed function stack. So we only update gpr[1] but
1682  * don't emulate the real store operation. We will do real store
1683  * operation safely in exception return code by checking this flag.
1684  */
1685 static __kprobes int handle_stack_update(unsigned long ea, struct pt_regs *regs)
1686 {
1687 #ifdef CONFIG_PPC32
1688 	/*
1689 	 * Check if we will touch kernel stack overflow
1690 	 */
1691 	if (ea - STACK_INT_FRAME_SIZE <= current->thread.ksp_limit) {
1692 		printk(KERN_CRIT "Can't kprobe this since kernel stack would overflow.\n");
1693 		return -EINVAL;
1694 	}
1695 #endif /* CONFIG_PPC32 */
1696 	/*
1697 	 * Check if we already set since that means we'll
1698 	 * lose the previous value.
1699 	 */
1700 	WARN_ON(test_thread_flag(TIF_EMULATE_STACK_STORE));
1701 	set_thread_flag(TIF_EMULATE_STACK_STORE);
1702 	return 0;
1703 }
1704 
1705 static __kprobes void do_signext(unsigned long *valp, int size)
1706 {
1707 	switch (size) {
1708 	case 2:
1709 		*valp = (signed short) *valp;
1710 		break;
1711 	case 4:
1712 		*valp = (signed int) *valp;
1713 		break;
1714 	}
1715 }
1716 
1717 static __kprobes void do_byterev(unsigned long *valp, int size)
1718 {
1719 	switch (size) {
1720 	case 2:
1721 		*valp = byterev_2(*valp);
1722 		break;
1723 	case 4:
1724 		*valp = byterev_4(*valp);
1725 		break;
1726 #ifdef __powerpc64__
1727 	case 8:
1728 		*valp = byterev_8(*valp);
1729 		break;
1730 #endif
1731 	}
1732 }
1733 
1734 /*
1735  * Emulate instructions that cause a transfer of control,
1736  * loads and stores, and a few other instructions.
1737  * Returns 1 if the step was emulated, 0 if not,
1738  * or -1 if the instruction is one that should not be stepped,
1739  * such as an rfid, or a mtmsrd that would clear MSR_RI.
1740  */
1741 int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
1742 {
1743 	struct instruction_op op;
1744 	int r, err, size;
1745 	unsigned long val;
1746 	unsigned int cr;
1747 	int rd;
1748 
1749 	r = analyse_instr(&op, regs, instr);
1750 	if (r != 0)
1751 		return r;
1752 
1753 	err = 0;
1754 	size = GETSIZE(op.type);
1755 	switch (op.type & INSTR_TYPE_MASK) {
1756 	case CACHEOP:
1757 		if (!address_ok(regs, op.ea, 8))
1758 			return 0;
1759 		switch (op.type & CACHEOP_MASK) {
1760 		case DCBST:
1761 			__cacheop_user_asmx(op.ea, err, "dcbst");
1762 			break;
1763 		case DCBF:
1764 			__cacheop_user_asmx(op.ea, err, "dcbf");
1765 			break;
1766 		case DCBTST:
1767 			if (op.reg == 0)
1768 				prefetchw((void *) op.ea);
1769 			break;
1770 		case DCBT:
1771 			if (op.reg == 0)
1772 				prefetch((void *) op.ea);
1773 			break;
1774 		case ICBI:
1775 			__cacheop_user_asmx(op.ea, err, "icbi");
1776 			break;
1777 		}
1778 		if (err)
1779 			return 0;
1780 		goto instr_done;
1781 
1782 	case LARX:
1783 		if (regs->msr & MSR_LE)
1784 			return 0;
1785 		if (op.ea & (size - 1))
1786 			break;		/* can't handle misaligned */
1787 		err = -EFAULT;
1788 		if (!address_ok(regs, op.ea, size))
1789 			goto ldst_done;
1790 		err = 0;
1791 		switch (size) {
1792 		case 4:
1793 			__get_user_asmx(val, op.ea, err, "lwarx");
1794 			break;
1795 		case 8:
1796 			__get_user_asmx(val, op.ea, err, "ldarx");
1797 			break;
1798 		default:
1799 			return 0;
1800 		}
1801 		if (!err)
1802 			regs->gpr[op.reg] = val;
1803 		goto ldst_done;
1804 
1805 	case STCX:
1806 		if (regs->msr & MSR_LE)
1807 			return 0;
1808 		if (op.ea & (size - 1))
1809 			break;		/* can't handle misaligned */
1810 		err = -EFAULT;
1811 		if (!address_ok(regs, op.ea, size))
1812 			goto ldst_done;
1813 		err = 0;
1814 		switch (size) {
1815 		case 4:
1816 			__put_user_asmx(op.val, op.ea, err, "stwcx.", cr);
1817 			break;
1818 		case 8:
1819 			__put_user_asmx(op.val, op.ea, err, "stdcx.", cr);
1820 			break;
1821 		default:
1822 			return 0;
1823 		}
1824 		if (!err)
1825 			regs->ccr = (regs->ccr & 0x0fffffff) |
1826 				(cr & 0xe0000000) |
1827 				((regs->xer >> 3) & 0x10000000);
1828 		goto ldst_done;
1829 
1830 	case LOAD:
1831 		if (regs->msr & MSR_LE)
1832 			return 0;
1833 		err = read_mem(&regs->gpr[op.reg], op.ea, size, regs);
1834 		if (!err) {
1835 			if (op.type & SIGNEXT)
1836 				do_signext(&regs->gpr[op.reg], size);
1837 			if (op.type & BYTEREV)
1838 				do_byterev(&regs->gpr[op.reg], size);
1839 		}
1840 		goto ldst_done;
1841 
1842 	case LOAD_FP:
1843 		if (regs->msr & MSR_LE)
1844 			return 0;
1845 		if (size == 4)
1846 			err = do_fp_load(op.reg, do_lfs, op.ea, size, regs);
1847 		else
1848 			err = do_fp_load(op.reg, do_lfd, op.ea, size, regs);
1849 		goto ldst_done;
1850 
1851 #ifdef CONFIG_ALTIVEC
1852 	case LOAD_VMX:
1853 		if (regs->msr & MSR_LE)
1854 			return 0;
1855 		err = do_vec_load(op.reg, do_lvx, op.ea & ~0xfUL, regs);
1856 		goto ldst_done;
1857 #endif
1858 #ifdef CONFIG_VSX
1859 	case LOAD_VSX:
1860 		if (regs->msr & MSR_LE)
1861 			return 0;
1862 		err = do_vsx_load(op.reg, do_lxvd2x, op.ea, regs);
1863 		goto ldst_done;
1864 #endif
1865 	case LOAD_MULTI:
1866 		if (regs->msr & MSR_LE)
1867 			return 0;
1868 		rd = op.reg;
1869 		do {
1870 			err = read_mem(&regs->gpr[rd], op.ea, 4, regs);
1871 			if (err)
1872 				return 0;
1873 			op.ea += 4;
1874 		} while (++rd < 32);
1875 		goto instr_done;
1876 
1877 	case STORE:
1878 		if (regs->msr & MSR_LE)
1879 			return 0;
1880 		if ((op.type & UPDATE) && size == sizeof(long) &&
1881 		    op.reg == 1 && op.update_reg == 1 &&
1882 		    !(regs->msr & MSR_PR) &&
1883 		    op.ea >= regs->gpr[1] - STACK_INT_FRAME_SIZE) {
1884 			err = handle_stack_update(op.ea, regs);
1885 			goto ldst_done;
1886 		}
1887 		err = write_mem(op.val, op.ea, size, regs);
1888 		goto ldst_done;
1889 
1890 	case STORE_FP:
1891 		if (regs->msr & MSR_LE)
1892 			return 0;
1893 		if (size == 4)
1894 			err = do_fp_store(op.reg, do_stfs, op.ea, size, regs);
1895 		else
1896 			err = do_fp_store(op.reg, do_stfd, op.ea, size, regs);
1897 		goto ldst_done;
1898 
1899 #ifdef CONFIG_ALTIVEC
1900 	case STORE_VMX:
1901 		if (regs->msr & MSR_LE)
1902 			return 0;
1903 		err = do_vec_store(op.reg, do_stvx, op.ea & ~0xfUL, regs);
1904 		goto ldst_done;
1905 #endif
1906 #ifdef CONFIG_VSX
1907 	case STORE_VSX:
1908 		if (regs->msr & MSR_LE)
1909 			return 0;
1910 		err = do_vsx_store(op.reg, do_stxvd2x, op.ea, regs);
1911 		goto ldst_done;
1912 #endif
1913 	case STORE_MULTI:
1914 		if (regs->msr & MSR_LE)
1915 			return 0;
1916 		rd = op.reg;
1917 		do {
1918 			err = write_mem(regs->gpr[rd], op.ea, 4, regs);
1919 			if (err)
1920 				return 0;
1921 			op.ea += 4;
1922 		} while (++rd < 32);
1923 		goto instr_done;
1924 
1925 	case MFMSR:
1926 		regs->gpr[op.reg] = regs->msr & MSR_MASK;
1927 		goto instr_done;
1928 
1929 	case MTMSR:
1930 		val = regs->gpr[op.reg];
1931 		if ((val & MSR_RI) == 0)
1932 			/* can't step mtmsr[d] that would clear MSR_RI */
1933 			return -1;
1934 		/* here op.val is the mask of bits to change */
1935 		regs->msr = (regs->msr & ~op.val) | (val & op.val);
1936 		goto instr_done;
1937 
1938 #ifdef CONFIG_PPC64
1939 	case SYSCALL:	/* sc */
1940 		/*
1941 		 * N.B. this uses knowledge about how the syscall
1942 		 * entry code works.  If that is changed, this will
1943 		 * need to be changed also.
1944 		 */
1945 		if (regs->gpr[0] == 0x1ebe &&
1946 		    cpu_has_feature(CPU_FTR_REAL_LE)) {
1947 			regs->msr ^= MSR_LE;
1948 			goto instr_done;
1949 		}
1950 		regs->gpr[9] = regs->gpr[13];
1951 		regs->gpr[10] = MSR_KERNEL;
1952 		regs->gpr[11] = regs->nip + 4;
1953 		regs->gpr[12] = regs->msr & MSR_MASK;
1954 		regs->gpr[13] = (unsigned long) get_paca();
1955 		regs->nip = (unsigned long) &system_call_common;
1956 		regs->msr = MSR_KERNEL;
1957 		return 1;
1958 
1959 	case RFI:
1960 		return -1;
1961 #endif
1962 	}
1963 	return 0;
1964 
1965  ldst_done:
1966 	if (err)
1967 		return 0;
1968 	if (op.type & UPDATE)
1969 		regs->gpr[op.update_reg] = op.ea;
1970 
1971  instr_done:
1972 	regs->nip = truncate_if_32bit(regs->msr, regs->nip + 4);
1973 	return 1;
1974 }
1975