1 /*
2 * arch/arm/kernel/kprobes-decode.c
3 *
4 * Copyright (C) 2006, 2007 Motorola Inc.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
14 */
15
16 /*
17 * We do not have hardware single-stepping on ARM, This
18 * effort is further complicated by the ARM not having a
19 * "next PC" register. Instructions that change the PC
20 * can't be safely single-stepped in a MP environment, so
21 * we have a lot of work to do:
22 *
23 * In the prepare phase:
24 * *) If it is an instruction that does anything
25 * with the CPU mode, we reject it for a kprobe.
26 * (This is out of laziness rather than need. The
27 * instructions could be simulated.)
28 *
29 * *) Otherwise, decode the instruction rewriting its
30 * registers to take fixed, ordered registers and
31 * setting a handler for it to run the instruction.
32 *
33 * In the execution phase by an instruction's handler:
34 *
35 * *) If the PC is written to by the instruction, the
36 * instruction must be fully simulated in software.
37 * If it is a conditional instruction, the handler
38 * will use insn[0] to copy its condition code to
39 * set r0 to 1 and insn[1] to "mov pc, lr" to return.
40 *
41 * *) Otherwise, a modified form of the instruction is
42 * directly executed. Its handler calls the
43 * instruction in insn[0]. In insn[1] is a
44 * "mov pc, lr" to return.
45 *
46 * Before calling, load up the reordered registers
47 * from the original instruction's registers. If one
48 * of the original input registers is the PC, compute
49 * and adjust the appropriate input register.
50 *
51 * After call completes, copy the output registers to
52 * the original instruction's original registers.
53 *
54 * We don't use a real breakpoint instruction since that
55 * would have us in the kernel go from SVC mode to SVC
56 * mode losing the link register. Instead we use an
57 * undefined instruction. To simplify processing, the
58 * undefined instruction used for kprobes must be reserved
59 * exclusively for kprobes use.
60 *
61 * TODO: ifdef out some instruction decoding based on architecture.
62 */
63
64 #include <linux/kernel.h>
65 #include <linux/kprobes.h>
66
67 #define sign_extend(x, signbit) ((x) | (0 - ((x) & (1 << (signbit)))))
68
69 #define branch_displacement(insn) sign_extend(((insn) & 0xffffff) << 2, 25)
70
71 #define PSR_fs (PSR_f|PSR_s)
72
73 #define KPROBE_RETURN_INSTRUCTION 0xe1a0f00e /* mov pc, lr */
74 #define SET_R0_TRUE_INSTRUCTION 0xe3a00001 /* mov r0, #1 */
75
76 #define truecc_insn(insn) (((insn) & 0xf0000000) | \
77 (SET_R0_TRUE_INSTRUCTION & 0x0fffffff))
78
79 typedef long (insn_0arg_fn_t)(void);
80 typedef long (insn_1arg_fn_t)(long);
81 typedef long (insn_2arg_fn_t)(long, long);
82 typedef long (insn_3arg_fn_t)(long, long, long);
83 typedef long (insn_4arg_fn_t)(long, long, long, long);
84 typedef long long (insn_llret_0arg_fn_t)(void);
85 typedef long long (insn_llret_3arg_fn_t)(long, long, long);
86 typedef long long (insn_llret_4arg_fn_t)(long, long, long, long);
87
88 union reg_pair {
89 long long dr;
90 #ifdef __LITTLE_ENDIAN
91 struct { long r0, r1; };
92 #else
93 struct { long r1, r0; };
94 #endif
95 };
96
97 /*
98 * For STR and STM instructions, an ARM core may choose to use either
99 * a +8 or a +12 displacement from the current instruction's address.
100 * Whichever value is chosen for a given core, it must be the same for
101 * both instructions and may not change. This function measures it.
102 */
103
104 static int str_pc_offset;
105
find_str_pc_offset(void)106 static void __init find_str_pc_offset(void)
107 {
108 int addr, scratch, ret;
109
110 __asm__ (
111 "sub %[ret], pc, #4 \n\t"
112 "str pc, %[addr] \n\t"
113 "ldr %[scr], %[addr] \n\t"
114 "sub %[ret], %[scr], %[ret] \n\t"
115 : [ret] "=r" (ret), [scr] "=r" (scratch), [addr] "+m" (addr));
116
117 str_pc_offset = ret;
118 }
119
120 /*
121 * The insnslot_?arg_r[w]flags() functions below are to keep the
122 * msr -> *fn -> mrs instruction sequences indivisible so that
123 * the state of the CPSR flags aren't inadvertently modified
124 * just before or just after the call.
125 */
126
127 static inline long __kprobes
insnslot_0arg_rflags(long cpsr,insn_0arg_fn_t * fn)128 insnslot_0arg_rflags(long cpsr, insn_0arg_fn_t *fn)
129 {
130 register long ret asm("r0");
131
132 __asm__ __volatile__ (
133 "msr cpsr_fs, %[cpsr] \n\t"
134 "mov lr, pc \n\t"
135 "mov pc, %[fn] \n\t"
136 : "=r" (ret)
137 : [cpsr] "r" (cpsr), [fn] "r" (fn)
138 : "lr", "cc"
139 );
140 return ret;
141 }
142
143 static inline long long __kprobes
insnslot_llret_0arg_rflags(long cpsr,insn_llret_0arg_fn_t * fn)144 insnslot_llret_0arg_rflags(long cpsr, insn_llret_0arg_fn_t *fn)
145 {
146 register long ret0 asm("r0");
147 register long ret1 asm("r1");
148 union reg_pair fnr;
149
150 __asm__ __volatile__ (
151 "msr cpsr_fs, %[cpsr] \n\t"
152 "mov lr, pc \n\t"
153 "mov pc, %[fn] \n\t"
154 : "=r" (ret0), "=r" (ret1)
155 : [cpsr] "r" (cpsr), [fn] "r" (fn)
156 : "lr", "cc"
157 );
158 fnr.r0 = ret0;
159 fnr.r1 = ret1;
160 return fnr.dr;
161 }
162
163 static inline long __kprobes
insnslot_1arg_rflags(long r0,long cpsr,insn_1arg_fn_t * fn)164 insnslot_1arg_rflags(long r0, long cpsr, insn_1arg_fn_t *fn)
165 {
166 register long rr0 asm("r0") = r0;
167 register long ret asm("r0");
168
169 __asm__ __volatile__ (
170 "msr cpsr_fs, %[cpsr] \n\t"
171 "mov lr, pc \n\t"
172 "mov pc, %[fn] \n\t"
173 : "=r" (ret)
174 : "0" (rr0), [cpsr] "r" (cpsr), [fn] "r" (fn)
175 : "lr", "cc"
176 );
177 return ret;
178 }
179
180 static inline long __kprobes
insnslot_2arg_rflags(long r0,long r1,long cpsr,insn_2arg_fn_t * fn)181 insnslot_2arg_rflags(long r0, long r1, long cpsr, insn_2arg_fn_t *fn)
182 {
183 register long rr0 asm("r0") = r0;
184 register long rr1 asm("r1") = r1;
185 register long ret asm("r0");
186
187 __asm__ __volatile__ (
188 "msr cpsr_fs, %[cpsr] \n\t"
189 "mov lr, pc \n\t"
190 "mov pc, %[fn] \n\t"
191 : "=r" (ret)
192 : "0" (rr0), "r" (rr1),
193 [cpsr] "r" (cpsr), [fn] "r" (fn)
194 : "lr", "cc"
195 );
196 return ret;
197 }
198
199 static inline long __kprobes
insnslot_3arg_rflags(long r0,long r1,long r2,long cpsr,insn_3arg_fn_t * fn)200 insnslot_3arg_rflags(long r0, long r1, long r2, long cpsr, insn_3arg_fn_t *fn)
201 {
202 register long rr0 asm("r0") = r0;
203 register long rr1 asm("r1") = r1;
204 register long rr2 asm("r2") = r2;
205 register long ret asm("r0");
206
207 __asm__ __volatile__ (
208 "msr cpsr_fs, %[cpsr] \n\t"
209 "mov lr, pc \n\t"
210 "mov pc, %[fn] \n\t"
211 : "=r" (ret)
212 : "0" (rr0), "r" (rr1), "r" (rr2),
213 [cpsr] "r" (cpsr), [fn] "r" (fn)
214 : "lr", "cc"
215 );
216 return ret;
217 }
218
219 static inline long long __kprobes
insnslot_llret_3arg_rflags(long r0,long r1,long r2,long cpsr,insn_llret_3arg_fn_t * fn)220 insnslot_llret_3arg_rflags(long r0, long r1, long r2, long cpsr,
221 insn_llret_3arg_fn_t *fn)
222 {
223 register long rr0 asm("r0") = r0;
224 register long rr1 asm("r1") = r1;
225 register long rr2 asm("r2") = r2;
226 register long ret0 asm("r0");
227 register long ret1 asm("r1");
228 union reg_pair fnr;
229
230 __asm__ __volatile__ (
231 "msr cpsr_fs, %[cpsr] \n\t"
232 "mov lr, pc \n\t"
233 "mov pc, %[fn] \n\t"
234 : "=r" (ret0), "=r" (ret1)
235 : "0" (rr0), "r" (rr1), "r" (rr2),
236 [cpsr] "r" (cpsr), [fn] "r" (fn)
237 : "lr", "cc"
238 );
239 fnr.r0 = ret0;
240 fnr.r1 = ret1;
241 return fnr.dr;
242 }
243
244 static inline long __kprobes
insnslot_4arg_rflags(long r0,long r1,long r2,long r3,long cpsr,insn_4arg_fn_t * fn)245 insnslot_4arg_rflags(long r0, long r1, long r2, long r3, long cpsr,
246 insn_4arg_fn_t *fn)
247 {
248 register long rr0 asm("r0") = r0;
249 register long rr1 asm("r1") = r1;
250 register long rr2 asm("r2") = r2;
251 register long rr3 asm("r3") = r3;
252 register long ret asm("r0");
253
254 __asm__ __volatile__ (
255 "msr cpsr_fs, %[cpsr] \n\t"
256 "mov lr, pc \n\t"
257 "mov pc, %[fn] \n\t"
258 : "=r" (ret)
259 : "0" (rr0), "r" (rr1), "r" (rr2), "r" (rr3),
260 [cpsr] "r" (cpsr), [fn] "r" (fn)
261 : "lr", "cc"
262 );
263 return ret;
264 }
265
266 static inline long __kprobes
insnslot_1arg_rwflags(long r0,long * cpsr,insn_1arg_fn_t * fn)267 insnslot_1arg_rwflags(long r0, long *cpsr, insn_1arg_fn_t *fn)
268 {
269 register long rr0 asm("r0") = r0;
270 register long ret asm("r0");
271 long oldcpsr = *cpsr;
272 long newcpsr;
273
274 __asm__ __volatile__ (
275 "msr cpsr_fs, %[oldcpsr] \n\t"
276 "mov lr, pc \n\t"
277 "mov pc, %[fn] \n\t"
278 "mrs %[newcpsr], cpsr \n\t"
279 : "=r" (ret), [newcpsr] "=r" (newcpsr)
280 : "0" (rr0), [oldcpsr] "r" (oldcpsr), [fn] "r" (fn)
281 : "lr", "cc"
282 );
283 *cpsr = (oldcpsr & ~PSR_fs) | (newcpsr & PSR_fs);
284 return ret;
285 }
286
287 static inline long __kprobes
insnslot_2arg_rwflags(long r0,long r1,long * cpsr,insn_2arg_fn_t * fn)288 insnslot_2arg_rwflags(long r0, long r1, long *cpsr, insn_2arg_fn_t *fn)
289 {
290 register long rr0 asm("r0") = r0;
291 register long rr1 asm("r1") = r1;
292 register long ret asm("r0");
293 long oldcpsr = *cpsr;
294 long newcpsr;
295
296 __asm__ __volatile__ (
297 "msr cpsr_fs, %[oldcpsr] \n\t"
298 "mov lr, pc \n\t"
299 "mov pc, %[fn] \n\t"
300 "mrs %[newcpsr], cpsr \n\t"
301 : "=r" (ret), [newcpsr] "=r" (newcpsr)
302 : "0" (rr0), "r" (rr1), [oldcpsr] "r" (oldcpsr), [fn] "r" (fn)
303 : "lr", "cc"
304 );
305 *cpsr = (oldcpsr & ~PSR_fs) | (newcpsr & PSR_fs);
306 return ret;
307 }
308
309 static inline long __kprobes
insnslot_3arg_rwflags(long r0,long r1,long r2,long * cpsr,insn_3arg_fn_t * fn)310 insnslot_3arg_rwflags(long r0, long r1, long r2, long *cpsr,
311 insn_3arg_fn_t *fn)
312 {
313 register long rr0 asm("r0") = r0;
314 register long rr1 asm("r1") = r1;
315 register long rr2 asm("r2") = r2;
316 register long ret asm("r0");
317 long oldcpsr = *cpsr;
318 long newcpsr;
319
320 __asm__ __volatile__ (
321 "msr cpsr_fs, %[oldcpsr] \n\t"
322 "mov lr, pc \n\t"
323 "mov pc, %[fn] \n\t"
324 "mrs %[newcpsr], cpsr \n\t"
325 : "=r" (ret), [newcpsr] "=r" (newcpsr)
326 : "0" (rr0), "r" (rr1), "r" (rr2),
327 [oldcpsr] "r" (oldcpsr), [fn] "r" (fn)
328 : "lr", "cc"
329 );
330 *cpsr = (oldcpsr & ~PSR_fs) | (newcpsr & PSR_fs);
331 return ret;
332 }
333
334 static inline long __kprobes
insnslot_4arg_rwflags(long r0,long r1,long r2,long r3,long * cpsr,insn_4arg_fn_t * fn)335 insnslot_4arg_rwflags(long r0, long r1, long r2, long r3, long *cpsr,
336 insn_4arg_fn_t *fn)
337 {
338 register long rr0 asm("r0") = r0;
339 register long rr1 asm("r1") = r1;
340 register long rr2 asm("r2") = r2;
341 register long rr3 asm("r3") = r3;
342 register long ret asm("r0");
343 long oldcpsr = *cpsr;
344 long newcpsr;
345
346 __asm__ __volatile__ (
347 "msr cpsr_fs, %[oldcpsr] \n\t"
348 "mov lr, pc \n\t"
349 "mov pc, %[fn] \n\t"
350 "mrs %[newcpsr], cpsr \n\t"
351 : "=r" (ret), [newcpsr] "=r" (newcpsr)
352 : "0" (rr0), "r" (rr1), "r" (rr2), "r" (rr3),
353 [oldcpsr] "r" (oldcpsr), [fn] "r" (fn)
354 : "lr", "cc"
355 );
356 *cpsr = (oldcpsr & ~PSR_fs) | (newcpsr & PSR_fs);
357 return ret;
358 }
359
360 static inline long long __kprobes
insnslot_llret_4arg_rwflags(long r0,long r1,long r2,long r3,long * cpsr,insn_llret_4arg_fn_t * fn)361 insnslot_llret_4arg_rwflags(long r0, long r1, long r2, long r3, long *cpsr,
362 insn_llret_4arg_fn_t *fn)
363 {
364 register long rr0 asm("r0") = r0;
365 register long rr1 asm("r1") = r1;
366 register long rr2 asm("r2") = r2;
367 register long rr3 asm("r3") = r3;
368 register long ret0 asm("r0");
369 register long ret1 asm("r1");
370 long oldcpsr = *cpsr;
371 long newcpsr;
372 union reg_pair fnr;
373
374 __asm__ __volatile__ (
375 "msr cpsr_fs, %[oldcpsr] \n\t"
376 "mov lr, pc \n\t"
377 "mov pc, %[fn] \n\t"
378 "mrs %[newcpsr], cpsr \n\t"
379 : "=r" (ret0), "=r" (ret1), [newcpsr] "=r" (newcpsr)
380 : "0" (rr0), "r" (rr1), "r" (rr2), "r" (rr3),
381 [oldcpsr] "r" (oldcpsr), [fn] "r" (fn)
382 : "lr", "cc"
383 );
384 *cpsr = (oldcpsr & ~PSR_fs) | (newcpsr & PSR_fs);
385 fnr.r0 = ret0;
386 fnr.r1 = ret1;
387 return fnr.dr;
388 }
389
390 /*
391 * To avoid the complications of mimicing single-stepping on a
392 * processor without a Next-PC or a single-step mode, and to
393 * avoid having to deal with the side-effects of boosting, we
394 * simulate or emulate (almost) all ARM instructions.
395 *
396 * "Simulation" is where the instruction's behavior is duplicated in
397 * C code. "Emulation" is where the original instruction is rewritten
398 * and executed, often by altering its registers.
399 *
400 * By having all behavior of the kprobe'd instruction completed before
401 * returning from the kprobe_handler(), all locks (scheduler and
402 * interrupt) can safely be released. There is no need for secondary
403 * breakpoints, no race with MP or preemptable kernels, nor having to
404 * clean up resources counts at a later time impacting overall system
405 * performance. By rewriting the instruction, only the minimum registers
406 * need to be loaded and saved back optimizing performance.
407 *
408 * Calling the insnslot_*_rwflags version of a function doesn't hurt
409 * anything even when the CPSR flags aren't updated by the
410 * instruction. It's just a little slower in return for saving
411 * a little space by not having a duplicate function that doesn't
412 * update the flags. (The same optimization can be said for
413 * instructions that do or don't perform register writeback)
414 * Also, instructions can either read the flags, only write the
415 * flags, or read and write the flags. To save combinations
416 * rather than for sheer performance, flag functions just assume
417 * read and write of flags.
418 */
419
simulate_bbl(struct kprobe * p,struct pt_regs * regs)420 static void __kprobes simulate_bbl(struct kprobe *p, struct pt_regs *regs)
421 {
422 insn_1arg_fn_t *i_fn = (insn_1arg_fn_t *)&p->ainsn.insn[0];
423 kprobe_opcode_t insn = p->opcode;
424 long iaddr = (long)p->addr;
425 int disp = branch_displacement(insn);
426
427 if (!insnslot_1arg_rflags(0, regs->ARM_cpsr, i_fn))
428 return;
429
430 if (insn & (1 << 24))
431 regs->ARM_lr = iaddr + 4;
432
433 regs->ARM_pc = iaddr + 8 + disp;
434 }
435
simulate_blx1(struct kprobe * p,struct pt_regs * regs)436 static void __kprobes simulate_blx1(struct kprobe *p, struct pt_regs *regs)
437 {
438 kprobe_opcode_t insn = p->opcode;
439 long iaddr = (long)p->addr;
440 int disp = branch_displacement(insn);
441
442 regs->ARM_lr = iaddr + 4;
443 regs->ARM_pc = iaddr + 8 + disp + ((insn >> 23) & 0x2);
444 regs->ARM_cpsr |= PSR_T_BIT;
445 }
446
simulate_blx2bx(struct kprobe * p,struct pt_regs * regs)447 static void __kprobes simulate_blx2bx(struct kprobe *p, struct pt_regs *regs)
448 {
449 insn_1arg_fn_t *i_fn = (insn_1arg_fn_t *)&p->ainsn.insn[0];
450 kprobe_opcode_t insn = p->opcode;
451 int rm = insn & 0xf;
452 long rmv = regs->uregs[rm];
453
454 if (!insnslot_1arg_rflags(0, regs->ARM_cpsr, i_fn))
455 return;
456
457 if (insn & (1 << 5))
458 regs->ARM_lr = (long)p->addr + 4;
459
460 regs->ARM_pc = rmv & ~0x1;
461 regs->ARM_cpsr &= ~PSR_T_BIT;
462 if (rmv & 0x1)
463 regs->ARM_cpsr |= PSR_T_BIT;
464 }
465
simulate_ldm1stm1(struct kprobe * p,struct pt_regs * regs)466 static void __kprobes simulate_ldm1stm1(struct kprobe *p, struct pt_regs *regs)
467 {
468 insn_1arg_fn_t *i_fn = (insn_1arg_fn_t *)&p->ainsn.insn[0];
469 kprobe_opcode_t insn = p->opcode;
470 int rn = (insn >> 16) & 0xf;
471 int lbit = insn & (1 << 20);
472 int wbit = insn & (1 << 21);
473 int ubit = insn & (1 << 23);
474 int pbit = insn & (1 << 24);
475 long *addr = (long *)regs->uregs[rn];
476 int reg_bit_vector;
477 int reg_count;
478
479 if (!insnslot_1arg_rflags(0, regs->ARM_cpsr, i_fn))
480 return;
481
482 reg_count = 0;
483 reg_bit_vector = insn & 0xffff;
484 while (reg_bit_vector) {
485 reg_bit_vector &= (reg_bit_vector - 1);
486 ++reg_count;
487 }
488
489 if (!ubit)
490 addr -= reg_count;
491 addr += (!pbit == !ubit);
492
493 reg_bit_vector = insn & 0xffff;
494 while (reg_bit_vector) {
495 int reg = __ffs(reg_bit_vector);
496 reg_bit_vector &= (reg_bit_vector - 1);
497 if (lbit)
498 regs->uregs[reg] = *addr++;
499 else
500 *addr++ = regs->uregs[reg];
501 }
502
503 if (wbit) {
504 if (!ubit)
505 addr -= reg_count;
506 addr -= (!pbit == !ubit);
507 regs->uregs[rn] = (long)addr;
508 }
509 }
510
simulate_stm1_pc(struct kprobe * p,struct pt_regs * regs)511 static void __kprobes simulate_stm1_pc(struct kprobe *p, struct pt_regs *regs)
512 {
513 insn_1arg_fn_t *i_fn = (insn_1arg_fn_t *)&p->ainsn.insn[0];
514
515 if (!insnslot_1arg_rflags(0, regs->ARM_cpsr, i_fn))
516 return;
517
518 regs->ARM_pc = (long)p->addr + str_pc_offset;
519 simulate_ldm1stm1(p, regs);
520 regs->ARM_pc = (long)p->addr + 4;
521 }
522
simulate_mov_ipsp(struct kprobe * p,struct pt_regs * regs)523 static void __kprobes simulate_mov_ipsp(struct kprobe *p, struct pt_regs *regs)
524 {
525 regs->uregs[12] = regs->uregs[13];
526 }
527
emulate_ldcstc(struct kprobe * p,struct pt_regs * regs)528 static void __kprobes emulate_ldcstc(struct kprobe *p, struct pt_regs *regs)
529 {
530 insn_1arg_fn_t *i_fn = (insn_1arg_fn_t *)&p->ainsn.insn[0];
531 kprobe_opcode_t insn = p->opcode;
532 int rn = (insn >> 16) & 0xf;
533 long rnv = regs->uregs[rn];
534
535 /* Save Rn in case of writeback. */
536 regs->uregs[rn] = insnslot_1arg_rflags(rnv, regs->ARM_cpsr, i_fn);
537 }
538
emulate_ldrd(struct kprobe * p,struct pt_regs * regs)539 static void __kprobes emulate_ldrd(struct kprobe *p, struct pt_regs *regs)
540 {
541 insn_2arg_fn_t *i_fn = (insn_2arg_fn_t *)&p->ainsn.insn[0];
542 kprobe_opcode_t insn = p->opcode;
543 int rd = (insn >> 12) & 0xf;
544 int rn = (insn >> 16) & 0xf;
545 int rm = insn & 0xf; /* rm may be invalid, don't care. */
546
547 /* Not following the C calling convention here, so need asm(). */
548 __asm__ __volatile__ (
549 "ldr r0, %[rn] \n\t"
550 "ldr r1, %[rm] \n\t"
551 "msr cpsr_fs, %[cpsr]\n\t"
552 "mov lr, pc \n\t"
553 "mov pc, %[i_fn] \n\t"
554 "str r0, %[rn] \n\t" /* in case of writeback */
555 "str r2, %[rd0] \n\t"
556 "str r3, %[rd1] \n\t"
557 : [rn] "+m" (regs->uregs[rn]),
558 [rd0] "=m" (regs->uregs[rd]),
559 [rd1] "=m" (regs->uregs[rd+1])
560 : [rm] "m" (regs->uregs[rm]),
561 [cpsr] "r" (regs->ARM_cpsr),
562 [i_fn] "r" (i_fn)
563 : "r0", "r1", "r2", "r3", "lr", "cc"
564 );
565 }
566
emulate_strd(struct kprobe * p,struct pt_regs * regs)567 static void __kprobes emulate_strd(struct kprobe *p, struct pt_regs *regs)
568 {
569 insn_4arg_fn_t *i_fn = (insn_4arg_fn_t *)&p->ainsn.insn[0];
570 kprobe_opcode_t insn = p->opcode;
571 int rd = (insn >> 12) & 0xf;
572 int rn = (insn >> 16) & 0xf;
573 int rm = insn & 0xf;
574 long rnv = regs->uregs[rn];
575 long rmv = regs->uregs[rm]; /* rm/rmv may be invalid, don't care. */
576
577 regs->uregs[rn] = insnslot_4arg_rflags(rnv, rmv, regs->uregs[rd],
578 regs->uregs[rd+1],
579 regs->ARM_cpsr, i_fn);
580 }
581
emulate_ldr(struct kprobe * p,struct pt_regs * regs)582 static void __kprobes emulate_ldr(struct kprobe *p, struct pt_regs *regs)
583 {
584 insn_llret_3arg_fn_t *i_fn = (insn_llret_3arg_fn_t *)&p->ainsn.insn[0];
585 kprobe_opcode_t insn = p->opcode;
586 union reg_pair fnr;
587 int rd = (insn >> 12) & 0xf;
588 int rn = (insn >> 16) & 0xf;
589 int rm = insn & 0xf;
590 long rdv;
591 long rnv = regs->uregs[rn];
592 long rmv = regs->uregs[rm]; /* rm/rmv may be invalid, don't care. */
593 long cpsr = regs->ARM_cpsr;
594
595 fnr.dr = insnslot_llret_3arg_rflags(rnv, 0, rmv, cpsr, i_fn);
596 regs->uregs[rn] = fnr.r0; /* Save Rn in case of writeback. */
597 rdv = fnr.r1;
598
599 if (rd == 15) {
600 #if __LINUX_ARM_ARCH__ >= 5
601 cpsr &= ~PSR_T_BIT;
602 if (rdv & 0x1)
603 cpsr |= PSR_T_BIT;
604 regs->ARM_cpsr = cpsr;
605 rdv &= ~0x1;
606 #else
607 rdv &= ~0x2;
608 #endif
609 }
610 regs->uregs[rd] = rdv;
611 }
612
emulate_str(struct kprobe * p,struct pt_regs * regs)613 static void __kprobes emulate_str(struct kprobe *p, struct pt_regs *regs)
614 {
615 insn_3arg_fn_t *i_fn = (insn_3arg_fn_t *)&p->ainsn.insn[0];
616 kprobe_opcode_t insn = p->opcode;
617 long iaddr = (long)p->addr;
618 int rd = (insn >> 12) & 0xf;
619 int rn = (insn >> 16) & 0xf;
620 int rm = insn & 0xf;
621 long rdv = (rd == 15) ? iaddr + str_pc_offset : regs->uregs[rd];
622 long rnv = (rn == 15) ? iaddr + 8 : regs->uregs[rn];
623 long rmv = regs->uregs[rm]; /* rm/rmv may be invalid, don't care. */
624
625 /* Save Rn in case of writeback. */
626 regs->uregs[rn] =
627 insnslot_3arg_rflags(rnv, rdv, rmv, regs->ARM_cpsr, i_fn);
628 }
629
emulate_mrrc(struct kprobe * p,struct pt_regs * regs)630 static void __kprobes emulate_mrrc(struct kprobe *p, struct pt_regs *regs)
631 {
632 insn_llret_0arg_fn_t *i_fn = (insn_llret_0arg_fn_t *)&p->ainsn.insn[0];
633 kprobe_opcode_t insn = p->opcode;
634 union reg_pair fnr;
635 int rd = (insn >> 12) & 0xf;
636 int rn = (insn >> 16) & 0xf;
637
638 fnr.dr = insnslot_llret_0arg_rflags(regs->ARM_cpsr, i_fn);
639 regs->uregs[rn] = fnr.r0;
640 regs->uregs[rd] = fnr.r1;
641 }
642
emulate_mcrr(struct kprobe * p,struct pt_regs * regs)643 static void __kprobes emulate_mcrr(struct kprobe *p, struct pt_regs *regs)
644 {
645 insn_2arg_fn_t *i_fn = (insn_2arg_fn_t *)&p->ainsn.insn[0];
646 kprobe_opcode_t insn = p->opcode;
647 int rd = (insn >> 12) & 0xf;
648 int rn = (insn >> 16) & 0xf;
649 long rnv = regs->uregs[rn];
650 long rdv = regs->uregs[rd];
651
652 insnslot_2arg_rflags(rnv, rdv, regs->ARM_cpsr, i_fn);
653 }
654
emulate_sat(struct kprobe * p,struct pt_regs * regs)655 static void __kprobes emulate_sat(struct kprobe *p, struct pt_regs *regs)
656 {
657 insn_1arg_fn_t *i_fn = (insn_1arg_fn_t *)&p->ainsn.insn[0];
658 kprobe_opcode_t insn = p->opcode;
659 int rd = (insn >> 12) & 0xf;
660 int rm = insn & 0xf;
661 long rmv = regs->uregs[rm];
662
663 /* Writes Q flag */
664 regs->uregs[rd] = insnslot_1arg_rwflags(rmv, ®s->ARM_cpsr, i_fn);
665 }
666
emulate_sel(struct kprobe * p,struct pt_regs * regs)667 static void __kprobes emulate_sel(struct kprobe *p, struct pt_regs *regs)
668 {
669 insn_2arg_fn_t *i_fn = (insn_2arg_fn_t *)&p->ainsn.insn[0];
670 kprobe_opcode_t insn = p->opcode;
671 int rd = (insn >> 12) & 0xf;
672 int rn = (insn >> 16) & 0xf;
673 int rm = insn & 0xf;
674 long rnv = regs->uregs[rn];
675 long rmv = regs->uregs[rm];
676
677 /* Reads GE bits */
678 regs->uregs[rd] = insnslot_2arg_rflags(rnv, rmv, regs->ARM_cpsr, i_fn);
679 }
680
emulate_none(struct kprobe * p,struct pt_regs * regs)681 static void __kprobes emulate_none(struct kprobe *p, struct pt_regs *regs)
682 {
683 insn_0arg_fn_t *i_fn = (insn_0arg_fn_t *)&p->ainsn.insn[0];
684
685 insnslot_0arg_rflags(regs->ARM_cpsr, i_fn);
686 }
687
emulate_rd12(struct kprobe * p,struct pt_regs * regs)688 static void __kprobes emulate_rd12(struct kprobe *p, struct pt_regs *regs)
689 {
690 insn_0arg_fn_t *i_fn = (insn_0arg_fn_t *)&p->ainsn.insn[0];
691 kprobe_opcode_t insn = p->opcode;
692 int rd = (insn >> 12) & 0xf;
693
694 regs->uregs[rd] = insnslot_0arg_rflags(regs->ARM_cpsr, i_fn);
695 }
696
emulate_ird12(struct kprobe * p,struct pt_regs * regs)697 static void __kprobes emulate_ird12(struct kprobe *p, struct pt_regs *regs)
698 {
699 insn_1arg_fn_t *i_fn = (insn_1arg_fn_t *)&p->ainsn.insn[0];
700 kprobe_opcode_t insn = p->opcode;
701 int ird = (insn >> 12) & 0xf;
702
703 insnslot_1arg_rflags(regs->uregs[ird], regs->ARM_cpsr, i_fn);
704 }
705
emulate_rn16(struct kprobe * p,struct pt_regs * regs)706 static void __kprobes emulate_rn16(struct kprobe *p, struct pt_regs *regs)
707 {
708 insn_1arg_fn_t *i_fn = (insn_1arg_fn_t *)&p->ainsn.insn[0];
709 kprobe_opcode_t insn = p->opcode;
710 int rn = (insn >> 16) & 0xf;
711 long rnv = regs->uregs[rn];
712
713 insnslot_1arg_rflags(rnv, regs->ARM_cpsr, i_fn);
714 }
715
emulate_rd12rm0(struct kprobe * p,struct pt_regs * regs)716 static void __kprobes emulate_rd12rm0(struct kprobe *p, struct pt_regs *regs)
717 {
718 insn_1arg_fn_t *i_fn = (insn_1arg_fn_t *)&p->ainsn.insn[0];
719 kprobe_opcode_t insn = p->opcode;
720 int rd = (insn >> 12) & 0xf;
721 int rm = insn & 0xf;
722 long rmv = regs->uregs[rm];
723
724 regs->uregs[rd] = insnslot_1arg_rflags(rmv, regs->ARM_cpsr, i_fn);
725 }
726
727 static void __kprobes
emulate_rd12rn16rm0_rwflags(struct kprobe * p,struct pt_regs * regs)728 emulate_rd12rn16rm0_rwflags(struct kprobe *p, struct pt_regs *regs)
729 {
730 insn_2arg_fn_t *i_fn = (insn_2arg_fn_t *)&p->ainsn.insn[0];
731 kprobe_opcode_t insn = p->opcode;
732 int rd = (insn >> 12) & 0xf;
733 int rn = (insn >> 16) & 0xf;
734 int rm = insn & 0xf;
735 long rnv = regs->uregs[rn];
736 long rmv = regs->uregs[rm];
737
738 regs->uregs[rd] =
739 insnslot_2arg_rwflags(rnv, rmv, ®s->ARM_cpsr, i_fn);
740 }
741
742 static void __kprobes
emulate_rd16rn12rs8rm0_rwflags(struct kprobe * p,struct pt_regs * regs)743 emulate_rd16rn12rs8rm0_rwflags(struct kprobe *p, struct pt_regs *regs)
744 {
745 insn_3arg_fn_t *i_fn = (insn_3arg_fn_t *)&p->ainsn.insn[0];
746 kprobe_opcode_t insn = p->opcode;
747 int rd = (insn >> 16) & 0xf;
748 int rn = (insn >> 12) & 0xf;
749 int rs = (insn >> 8) & 0xf;
750 int rm = insn & 0xf;
751 long rnv = regs->uregs[rn];
752 long rsv = regs->uregs[rs];
753 long rmv = regs->uregs[rm];
754
755 regs->uregs[rd] =
756 insnslot_3arg_rwflags(rnv, rsv, rmv, ®s->ARM_cpsr, i_fn);
757 }
758
759 static void __kprobes
emulate_rd16rs8rm0_rwflags(struct kprobe * p,struct pt_regs * regs)760 emulate_rd16rs8rm0_rwflags(struct kprobe *p, struct pt_regs *regs)
761 {
762 insn_2arg_fn_t *i_fn = (insn_2arg_fn_t *)&p->ainsn.insn[0];
763 kprobe_opcode_t insn = p->opcode;
764 int rd = (insn >> 16) & 0xf;
765 int rs = (insn >> 8) & 0xf;
766 int rm = insn & 0xf;
767 long rsv = regs->uregs[rs];
768 long rmv = regs->uregs[rm];
769
770 regs->uregs[rd] =
771 insnslot_2arg_rwflags(rsv, rmv, ®s->ARM_cpsr, i_fn);
772 }
773
774 static void __kprobes
emulate_rdhi16rdlo12rs8rm0_rwflags(struct kprobe * p,struct pt_regs * regs)775 emulate_rdhi16rdlo12rs8rm0_rwflags(struct kprobe *p, struct pt_regs *regs)
776 {
777 insn_llret_4arg_fn_t *i_fn = (insn_llret_4arg_fn_t *)&p->ainsn.insn[0];
778 kprobe_opcode_t insn = p->opcode;
779 union reg_pair fnr;
780 int rdhi = (insn >> 16) & 0xf;
781 int rdlo = (insn >> 12) & 0xf;
782 int rs = (insn >> 8) & 0xf;
783 int rm = insn & 0xf;
784 long rsv = regs->uregs[rs];
785 long rmv = regs->uregs[rm];
786
787 fnr.dr = insnslot_llret_4arg_rwflags(regs->uregs[rdhi],
788 regs->uregs[rdlo], rsv, rmv,
789 ®s->ARM_cpsr, i_fn);
790 regs->uregs[rdhi] = fnr.r0;
791 regs->uregs[rdlo] = fnr.r1;
792 }
793
794 static void __kprobes
emulate_alu_imm_rflags(struct kprobe * p,struct pt_regs * regs)795 emulate_alu_imm_rflags(struct kprobe *p, struct pt_regs *regs)
796 {
797 insn_1arg_fn_t *i_fn = (insn_1arg_fn_t *)&p->ainsn.insn[0];
798 kprobe_opcode_t insn = p->opcode;
799 int rd = (insn >> 12) & 0xf;
800 int rn = (insn >> 16) & 0xf;
801 long rnv = (rn == 15) ? (long)p->addr + 8 : regs->uregs[rn];
802
803 regs->uregs[rd] = insnslot_1arg_rflags(rnv, regs->ARM_cpsr, i_fn);
804 }
805
806 static void __kprobes
emulate_alu_imm_rwflags(struct kprobe * p,struct pt_regs * regs)807 emulate_alu_imm_rwflags(struct kprobe *p, struct pt_regs *regs)
808 {
809 insn_1arg_fn_t *i_fn = (insn_1arg_fn_t *)&p->ainsn.insn[0];
810 kprobe_opcode_t insn = p->opcode;
811 int rd = (insn >> 12) & 0xf;
812 int rn = (insn >> 16) & 0xf;
813 long rnv = (rn == 15) ? (long)p->addr + 8 : regs->uregs[rn];
814
815 regs->uregs[rd] = insnslot_1arg_rwflags(rnv, ®s->ARM_cpsr, i_fn);
816 }
817
818 static void __kprobes
emulate_alu_rflags(struct kprobe * p,struct pt_regs * regs)819 emulate_alu_rflags(struct kprobe *p, struct pt_regs *regs)
820 {
821 insn_3arg_fn_t *i_fn = (insn_3arg_fn_t *)&p->ainsn.insn[0];
822 kprobe_opcode_t insn = p->opcode;
823 long ppc = (long)p->addr + 8;
824 int rd = (insn >> 12) & 0xf;
825 int rn = (insn >> 16) & 0xf; /* rn/rnv/rs/rsv may be */
826 int rs = (insn >> 8) & 0xf; /* invalid, don't care. */
827 int rm = insn & 0xf;
828 long rnv = (rn == 15) ? ppc : regs->uregs[rn];
829 long rmv = (rm == 15) ? ppc : regs->uregs[rm];
830 long rsv = regs->uregs[rs];
831
832 regs->uregs[rd] =
833 insnslot_3arg_rflags(rnv, rmv, rsv, regs->ARM_cpsr, i_fn);
834 }
835
836 static void __kprobes
emulate_alu_rwflags(struct kprobe * p,struct pt_regs * regs)837 emulate_alu_rwflags(struct kprobe *p, struct pt_regs *regs)
838 {
839 insn_3arg_fn_t *i_fn = (insn_3arg_fn_t *)&p->ainsn.insn[0];
840 kprobe_opcode_t insn = p->opcode;
841 long ppc = (long)p->addr + 8;
842 int rd = (insn >> 12) & 0xf;
843 int rn = (insn >> 16) & 0xf; /* rn/rnv/rs/rsv may be */
844 int rs = (insn >> 8) & 0xf; /* invalid, don't care. */
845 int rm = insn & 0xf;
846 long rnv = (rn == 15) ? ppc : regs->uregs[rn];
847 long rmv = (rm == 15) ? ppc : regs->uregs[rm];
848 long rsv = regs->uregs[rs];
849
850 regs->uregs[rd] =
851 insnslot_3arg_rwflags(rnv, rmv, rsv, ®s->ARM_cpsr, i_fn);
852 }
853
854 static enum kprobe_insn __kprobes
prep_emulate_ldr_str(kprobe_opcode_t insn,struct arch_specific_insn * asi)855 prep_emulate_ldr_str(kprobe_opcode_t insn, struct arch_specific_insn *asi)
856 {
857 int ibit = (insn & (1 << 26)) ? 25 : 22;
858
859 insn &= 0xfff00fff;
860 insn |= 0x00001000; /* Rn = r0, Rd = r1 */
861 if (insn & (1 << ibit)) {
862 insn &= ~0xf;
863 insn |= 2; /* Rm = r2 */
864 }
865 asi->insn[0] = insn;
866 asi->insn_handler = (insn & (1 << 20)) ? emulate_ldr : emulate_str;
867 return INSN_GOOD;
868 }
869
870 static enum kprobe_insn __kprobes
prep_emulate_rd12rm0(kprobe_opcode_t insn,struct arch_specific_insn * asi)871 prep_emulate_rd12rm0(kprobe_opcode_t insn, struct arch_specific_insn *asi)
872 {
873 insn &= 0xffff0ff0; /* Rd = r0, Rm = r0 */
874 asi->insn[0] = insn;
875 asi->insn_handler = emulate_rd12rm0;
876 return INSN_GOOD;
877 }
878
879 static enum kprobe_insn __kprobes
prep_emulate_rd12(kprobe_opcode_t insn,struct arch_specific_insn * asi)880 prep_emulate_rd12(kprobe_opcode_t insn, struct arch_specific_insn *asi)
881 {
882 insn &= 0xffff0fff; /* Rd = r0 */
883 asi->insn[0] = insn;
884 asi->insn_handler = emulate_rd12;
885 return INSN_GOOD;
886 }
887
888 static enum kprobe_insn __kprobes
prep_emulate_rd12rn16rm0_wflags(kprobe_opcode_t insn,struct arch_specific_insn * asi)889 prep_emulate_rd12rn16rm0_wflags(kprobe_opcode_t insn,
890 struct arch_specific_insn *asi)
891 {
892 insn &= 0xfff00ff0; /* Rd = r0, Rn = r0 */
893 insn |= 0x00000001; /* Rm = r1 */
894 asi->insn[0] = insn;
895 asi->insn_handler = emulate_rd12rn16rm0_rwflags;
896 return INSN_GOOD;
897 }
898
899 static enum kprobe_insn __kprobes
prep_emulate_rd16rs8rm0_wflags(kprobe_opcode_t insn,struct arch_specific_insn * asi)900 prep_emulate_rd16rs8rm0_wflags(kprobe_opcode_t insn,
901 struct arch_specific_insn *asi)
902 {
903 insn &= 0xfff0f0f0; /* Rd = r0, Rs = r0 */
904 insn |= 0x00000001; /* Rm = r1 */
905 asi->insn[0] = insn;
906 asi->insn_handler = emulate_rd16rs8rm0_rwflags;
907 return INSN_GOOD;
908 }
909
910 static enum kprobe_insn __kprobes
prep_emulate_rd16rn12rs8rm0_wflags(kprobe_opcode_t insn,struct arch_specific_insn * asi)911 prep_emulate_rd16rn12rs8rm0_wflags(kprobe_opcode_t insn,
912 struct arch_specific_insn *asi)
913 {
914 insn &= 0xfff000f0; /* Rd = r0, Rn = r0 */
915 insn |= 0x00000102; /* Rs = r1, Rm = r2 */
916 asi->insn[0] = insn;
917 asi->insn_handler = emulate_rd16rn12rs8rm0_rwflags;
918 return INSN_GOOD;
919 }
920
921 static enum kprobe_insn __kprobes
prep_emulate_rdhi16rdlo12rs8rm0_wflags(kprobe_opcode_t insn,struct arch_specific_insn * asi)922 prep_emulate_rdhi16rdlo12rs8rm0_wflags(kprobe_opcode_t insn,
923 struct arch_specific_insn *asi)
924 {
925 insn &= 0xfff000f0; /* RdHi = r0, RdLo = r1 */
926 insn |= 0x00001203; /* Rs = r2, Rm = r3 */
927 asi->insn[0] = insn;
928 asi->insn_handler = emulate_rdhi16rdlo12rs8rm0_rwflags;
929 return INSN_GOOD;
930 }
931
932 /*
933 * For the instruction masking and comparisons in all the "space_*"
934 * functions below, Do _not_ rearrange the order of tests unless
935 * you're very, very sure of what you are doing. For the sake of
936 * efficiency, the masks for some tests sometimes assume other test
937 * have been done prior to them so the number of patterns to test
938 * for an instruction set can be as broad as possible to reduce the
939 * number of tests needed.
940 */
941
942 static enum kprobe_insn __kprobes
space_1111(kprobe_opcode_t insn,struct arch_specific_insn * asi)943 space_1111(kprobe_opcode_t insn, struct arch_specific_insn *asi)
944 {
945 /* CPS mmod == 1 : 1111 0001 0000 xx10 xxxx xxxx xx0x xxxx */
946 /* RFE : 1111 100x x0x1 xxxx xxxx 1010 xxxx xxxx */
947 /* SRS : 1111 100x x1x0 1101 xxxx 0101 xxxx xxxx */
948 if ((insn & 0xfff30020) == 0xf1020000 ||
949 (insn & 0xfe500f00) == 0xf8100a00 ||
950 (insn & 0xfe5f0f00) == 0xf84d0500)
951 return INSN_REJECTED;
952
953 /* PLD : 1111 01x1 x101 xxxx xxxx xxxx xxxx xxxx : */
954 if ((insn & 0xfd700000) == 0xf4500000) {
955 insn &= 0xfff0ffff; /* Rn = r0 */
956 asi->insn[0] = insn;
957 asi->insn_handler = emulate_rn16;
958 return INSN_GOOD;
959 }
960
961 /* BLX(1) : 1111 101x xxxx xxxx xxxx xxxx xxxx xxxx : */
962 if ((insn & 0xfe000000) == 0xfa000000) {
963 asi->insn_handler = simulate_blx1;
964 return INSN_GOOD_NO_SLOT;
965 }
966
967 /* SETEND : 1111 0001 0000 0001 xxxx xxxx 0000 xxxx */
968 /* CDP2 : 1111 1110 xxxx xxxx xxxx xxxx xxx0 xxxx */
969 if ((insn & 0xffff00f0) == 0xf1010000 ||
970 (insn & 0xff000010) == 0xfe000000) {
971 asi->insn[0] = insn;
972 asi->insn_handler = emulate_none;
973 return INSN_GOOD;
974 }
975
976 /* MCRR2 : 1111 1100 0100 xxxx xxxx xxxx xxxx xxxx : (Rd != Rn) */
977 /* MRRC2 : 1111 1100 0101 xxxx xxxx xxxx xxxx xxxx : (Rd != Rn) */
978 if ((insn & 0xffe00000) == 0xfc400000) {
979 insn &= 0xfff00fff; /* Rn = r0 */
980 insn |= 0x00001000; /* Rd = r1 */
981 asi->insn[0] = insn;
982 asi->insn_handler =
983 (insn & (1 << 20)) ? emulate_mrrc : emulate_mcrr;
984 return INSN_GOOD;
985 }
986
987 /* LDC2 : 1111 110x xxx1 xxxx xxxx xxxx xxxx xxxx */
988 /* STC2 : 1111 110x xxx0 xxxx xxxx xxxx xxxx xxxx */
989 if ((insn & 0xfe000000) == 0xfc000000) {
990 insn &= 0xfff0ffff; /* Rn = r0 */
991 asi->insn[0] = insn;
992 asi->insn_handler = emulate_ldcstc;
993 return INSN_GOOD;
994 }
995
996 /* MCR2 : 1111 1110 xxx0 xxxx xxxx xxxx xxx1 xxxx */
997 /* MRC2 : 1111 1110 xxx1 xxxx xxxx xxxx xxx1 xxxx */
998 insn &= 0xffff0fff; /* Rd = r0 */
999 asi->insn[0] = insn;
1000 asi->insn_handler = (insn & (1 << 20)) ? emulate_rd12 : emulate_ird12;
1001 return INSN_GOOD;
1002 }
1003
1004 static enum kprobe_insn __kprobes
space_cccc_000x(kprobe_opcode_t insn,struct arch_specific_insn * asi)1005 space_cccc_000x(kprobe_opcode_t insn, struct arch_specific_insn *asi)
1006 {
1007 /* cccc 0001 0xx0 xxxx xxxx xxxx xxxx xxx0 xxxx */
1008 if ((insn & 0x0f900010) == 0x01000000) {
1009
1010 /* BXJ : cccc 0001 0010 xxxx xxxx xxxx 0010 xxxx */
1011 /* MSR : cccc 0001 0x10 xxxx xxxx xxxx 0000 xxxx */
1012 if ((insn & 0x0ff000f0) == 0x01200020 ||
1013 (insn & 0x0fb000f0) == 0x01200000)
1014 return INSN_REJECTED;
1015
1016 /* MRS : cccc 0001 0x00 xxxx xxxx xxxx 0000 xxxx */
1017 if ((insn & 0x0fb00010) == 0x01000000)
1018 return prep_emulate_rd12(insn, asi);
1019
1020 /* SMLALxy : cccc 0001 0100 xxxx xxxx xxxx 1xx0 xxxx */
1021 if ((insn & 0x0ff00090) == 0x01400080)
1022 return prep_emulate_rdhi16rdlo12rs8rm0_wflags(insn, asi);
1023
1024 /* SMULWy : cccc 0001 0010 xxxx xxxx xxxx 1x10 xxxx */
1025 /* SMULxy : cccc 0001 0110 xxxx xxxx xxxx 1xx0 xxxx */
1026 if ((insn & 0x0ff000b0) == 0x012000a0 ||
1027 (insn & 0x0ff00090) == 0x01600080)
1028 return prep_emulate_rd16rs8rm0_wflags(insn, asi);
1029
1030 /* SMLAxy : cccc 0001 0000 xxxx xxxx xxxx 1xx0 xxxx : Q */
1031 /* SMLAWy : cccc 0001 0010 xxxx xxxx xxxx 0x00 xxxx : Q */
1032 return prep_emulate_rd16rn12rs8rm0_wflags(insn, asi);
1033
1034 }
1035
1036 /* cccc 0001 0xx0 xxxx xxxx xxxx xxxx 0xx1 xxxx */
1037 else if ((insn & 0x0f900090) == 0x01000010) {
1038
1039 /* BKPT : 1110 0001 0010 xxxx xxxx xxxx 0111 xxxx */
1040 if ((insn & 0xfff000f0) == 0xe1200070)
1041 return INSN_REJECTED;
1042
1043 /* BLX(2) : cccc 0001 0010 xxxx xxxx xxxx 0011 xxxx */
1044 /* BX : cccc 0001 0010 xxxx xxxx xxxx 0001 xxxx */
1045 if ((insn & 0x0ff000d0) == 0x01200010) {
1046 asi->insn[0] = truecc_insn(insn);
1047 asi->insn_handler = simulate_blx2bx;
1048 return INSN_GOOD;
1049 }
1050
1051 /* CLZ : cccc 0001 0110 xxxx xxxx xxxx 0001 xxxx */
1052 if ((insn & 0x0ff000f0) == 0x01600010)
1053 return prep_emulate_rd12rm0(insn, asi);
1054
1055 /* QADD : cccc 0001 0000 xxxx xxxx xxxx 0101 xxxx :Q */
1056 /* QSUB : cccc 0001 0010 xxxx xxxx xxxx 0101 xxxx :Q */
1057 /* QDADD : cccc 0001 0100 xxxx xxxx xxxx 0101 xxxx :Q */
1058 /* QDSUB : cccc 0001 0110 xxxx xxxx xxxx 0101 xxxx :Q */
1059 return prep_emulate_rd12rn16rm0_wflags(insn, asi);
1060 }
1061
1062 /* cccc 0000 xxxx xxxx xxxx xxxx xxxx 1001 xxxx */
1063 else if ((insn & 0x0f000090) == 0x00000090) {
1064
1065 /* MUL : cccc 0000 0000 xxxx xxxx xxxx 1001 xxxx : */
1066 /* MULS : cccc 0000 0001 xxxx xxxx xxxx 1001 xxxx :cc */
1067 /* MLA : cccc 0000 0010 xxxx xxxx xxxx 1001 xxxx : */
1068 /* MLAS : cccc 0000 0011 xxxx xxxx xxxx 1001 xxxx :cc */
1069 /* UMAAL : cccc 0000 0100 xxxx xxxx xxxx 1001 xxxx : */
1070 /* UMULL : cccc 0000 1000 xxxx xxxx xxxx 1001 xxxx : */
1071 /* UMULLS : cccc 0000 1001 xxxx xxxx xxxx 1001 xxxx :cc */
1072 /* UMLAL : cccc 0000 1010 xxxx xxxx xxxx 1001 xxxx : */
1073 /* UMLALS : cccc 0000 1011 xxxx xxxx xxxx 1001 xxxx :cc */
1074 /* SMULL : cccc 0000 1100 xxxx xxxx xxxx 1001 xxxx : */
1075 /* SMULLS : cccc 0000 1101 xxxx xxxx xxxx 1001 xxxx :cc */
1076 /* SMLAL : cccc 0000 1110 xxxx xxxx xxxx 1001 xxxx : */
1077 /* SMLALS : cccc 0000 1111 xxxx xxxx xxxx 1001 xxxx :cc */
1078 if ((insn & 0x0fe000f0) == 0x00000090) {
1079 return prep_emulate_rd16rs8rm0_wflags(insn, asi);
1080 } else if ((insn & 0x0fe000f0) == 0x00200090) {
1081 return prep_emulate_rd16rn12rs8rm0_wflags(insn, asi);
1082 } else {
1083 return prep_emulate_rdhi16rdlo12rs8rm0_wflags(insn, asi);
1084 }
1085 }
1086
1087 /* cccc 000x xxxx xxxx xxxx xxxx xxxx 1xx1 xxxx */
1088 else if ((insn & 0x0e000090) == 0x00000090) {
1089
1090 /* SWP : cccc 0001 0000 xxxx xxxx xxxx 1001 xxxx */
1091 /* SWPB : cccc 0001 0100 xxxx xxxx xxxx 1001 xxxx */
1092 /* LDRD : cccc 000x xxx0 xxxx xxxx xxxx 1101 xxxx */
1093 /* STRD : cccc 000x xxx0 xxxx xxxx xxxx 1111 xxxx */
1094 /* STREX : cccc 0001 1000 xxxx xxxx xxxx 1001 xxxx */
1095 /* LDREX : cccc 0001 1001 xxxx xxxx xxxx 1001 xxxx */
1096 /* LDRH : cccc 000x xxx1 xxxx xxxx xxxx 1011 xxxx */
1097 /* STRH : cccc 000x xxx0 xxxx xxxx xxxx 1011 xxxx */
1098 /* LDRSB : cccc 000x xxx1 xxxx xxxx xxxx 1101 xxxx */
1099 /* LDRSH : cccc 000x xxx1 xxxx xxxx xxxx 1111 xxxx */
1100 if ((insn & 0x0fb000f0) == 0x01000090) {
1101 /* SWP/SWPB */
1102 return prep_emulate_rd12rn16rm0_wflags(insn, asi);
1103 } else if ((insn & 0x0e1000d0) == 0x00000d0) {
1104 /* STRD/LDRD */
1105 insn &= 0xfff00fff;
1106 insn |= 0x00002000; /* Rn = r0, Rd = r2 */
1107 if (insn & (1 << 22)) {
1108 /* I bit */
1109 insn &= ~0xf;
1110 insn |= 1; /* Rm = r1 */
1111 }
1112 asi->insn[0] = insn;
1113 asi->insn_handler =
1114 (insn & (1 << 5)) ? emulate_strd : emulate_ldrd;
1115 return INSN_GOOD;
1116 }
1117
1118 return prep_emulate_ldr_str(insn, asi);
1119 }
1120
1121 /* cccc 000x xxxx xxxx xxxx xxxx xxxx xxxx xxxx */
1122
1123 /*
1124 * ALU op with S bit and Rd == 15 :
1125 * cccc 000x xxx1 xxxx 1111 xxxx xxxx xxxx
1126 */
1127 if ((insn & 0x0e10f000) == 0x0010f000)
1128 return INSN_REJECTED;
1129
1130 /*
1131 * "mov ip, sp" is the most common kprobe'd instruction by far.
1132 * Check and optimize for it explicitly.
1133 */
1134 if (insn == 0xe1a0c00d) {
1135 asi->insn_handler = simulate_mov_ipsp;
1136 return INSN_GOOD_NO_SLOT;
1137 }
1138
1139 /*
1140 * Data processing: Immediate-shift / Register-shift
1141 * ALU op : cccc 000x xxxx xxxx xxxx xxxx xxxx xxxx
1142 * CPY : cccc 0001 1010 xxxx xxxx 0000 0000 xxxx
1143 * MOV : cccc 0001 101x xxxx xxxx xxxx xxxx xxxx
1144 * *S (bit 20) updates condition codes
1145 * ADC/SBC/RSC reads the C flag
1146 */
1147 insn &= 0xfff00ff0; /* Rn = r0, Rd = r0 */
1148 insn |= 0x00000001; /* Rm = r1 */
1149 if (insn & 0x010) {
1150 insn &= 0xfffff0ff; /* register shift */
1151 insn |= 0x00000200; /* Rs = r2 */
1152 }
1153 asi->insn[0] = insn;
1154 asi->insn_handler = (insn & (1 << 20)) ? /* S-bit */
1155 emulate_alu_rwflags : emulate_alu_rflags;
1156 return INSN_GOOD;
1157 }
1158
1159 static enum kprobe_insn __kprobes
space_cccc_001x(kprobe_opcode_t insn,struct arch_specific_insn * asi)1160 space_cccc_001x(kprobe_opcode_t insn, struct arch_specific_insn *asi)
1161 {
1162 /*
1163 * MSR : cccc 0011 0x10 xxxx xxxx xxxx xxxx xxxx
1164 * Undef : cccc 0011 0x00 xxxx xxxx xxxx xxxx xxxx
1165 * ALU op with S bit and Rd == 15 :
1166 * cccc 001x xxx1 xxxx 1111 xxxx xxxx xxxx
1167 */
1168 if ((insn & 0x0f900000) == 0x03200000 || /* MSR & Undef */
1169 (insn & 0x0e10f000) == 0x0210f000) /* ALU s-bit, R15 */
1170 return INSN_REJECTED;
1171
1172 /*
1173 * Data processing: 32-bit Immediate
1174 * ALU op : cccc 001x xxxx xxxx xxxx xxxx xxxx xxxx
1175 * MOV : cccc 0011 101x xxxx xxxx xxxx xxxx xxxx
1176 * *S (bit 20) updates condition codes
1177 * ADC/SBC/RSC reads the C flag
1178 */
1179 insn &= 0xfff00fff; /* Rn = r0, Rd = r0 */
1180 asi->insn[0] = insn;
1181 asi->insn_handler = (insn & (1 << 20)) ? /* S-bit */
1182 emulate_alu_imm_rwflags : emulate_alu_imm_rflags;
1183 return INSN_GOOD;
1184 }
1185
1186 static enum kprobe_insn __kprobes
space_cccc_0110__1(kprobe_opcode_t insn,struct arch_specific_insn * asi)1187 space_cccc_0110__1(kprobe_opcode_t insn, struct arch_specific_insn *asi)
1188 {
1189 /* SEL : cccc 0110 1000 xxxx xxxx xxxx 1011 xxxx GE: !!! */
1190 if ((insn & 0x0ff000f0) == 0x068000b0) {
1191 insn &= 0xfff00ff0; /* Rd = r0, Rn = r0 */
1192 insn |= 0x00000001; /* Rm = r1 */
1193 asi->insn[0] = insn;
1194 asi->insn_handler = emulate_sel;
1195 return INSN_GOOD;
1196 }
1197
1198 /* SSAT : cccc 0110 101x xxxx xxxx xxxx xx01 xxxx :Q */
1199 /* USAT : cccc 0110 111x xxxx xxxx xxxx xx01 xxxx :Q */
1200 /* SSAT16 : cccc 0110 1010 xxxx xxxx xxxx 0011 xxxx :Q */
1201 /* USAT16 : cccc 0110 1110 xxxx xxxx xxxx 0011 xxxx :Q */
1202 if ((insn & 0x0fa00030) == 0x06a00010 ||
1203 (insn & 0x0fb000f0) == 0x06a00030) {
1204 insn &= 0xffff0ff0; /* Rd = r0, Rm = r0 */
1205 asi->insn[0] = insn;
1206 asi->insn_handler = emulate_sat;
1207 return INSN_GOOD;
1208 }
1209
1210 /* REV : cccc 0110 1011 xxxx xxxx xxxx 0011 xxxx */
1211 /* REV16 : cccc 0110 1011 xxxx xxxx xxxx 1011 xxxx */
1212 /* REVSH : cccc 0110 1111 xxxx xxxx xxxx 1011 xxxx */
1213 if ((insn & 0x0ff00070) == 0x06b00030 ||
1214 (insn & 0x0ff000f0) == 0x06f000b0)
1215 return prep_emulate_rd12rm0(insn, asi);
1216
1217 /* SADD16 : cccc 0110 0001 xxxx xxxx xxxx 0001 xxxx :GE */
1218 /* SADDSUBX : cccc 0110 0001 xxxx xxxx xxxx 0011 xxxx :GE */
1219 /* SSUBADDX : cccc 0110 0001 xxxx xxxx xxxx 0101 xxxx :GE */
1220 /* SSUB16 : cccc 0110 0001 xxxx xxxx xxxx 0111 xxxx :GE */
1221 /* SADD8 : cccc 0110 0001 xxxx xxxx xxxx 1001 xxxx :GE */
1222 /* SSUB8 : cccc 0110 0001 xxxx xxxx xxxx 1111 xxxx :GE */
1223 /* QADD16 : cccc 0110 0010 xxxx xxxx xxxx 0001 xxxx : */
1224 /* QADDSUBX : cccc 0110 0010 xxxx xxxx xxxx 0011 xxxx : */
1225 /* QSUBADDX : cccc 0110 0010 xxxx xxxx xxxx 0101 xxxx : */
1226 /* QSUB16 : cccc 0110 0010 xxxx xxxx xxxx 0111 xxxx : */
1227 /* QADD8 : cccc 0110 0010 xxxx xxxx xxxx 1001 xxxx : */
1228 /* QSUB8 : cccc 0110 0010 xxxx xxxx xxxx 1111 xxxx : */
1229 /* SHADD16 : cccc 0110 0011 xxxx xxxx xxxx 0001 xxxx : */
1230 /* SHADDSUBX : cccc 0110 0011 xxxx xxxx xxxx 0011 xxxx : */
1231 /* SHSUBADDX : cccc 0110 0011 xxxx xxxx xxxx 0101 xxxx : */
1232 /* SHSUB16 : cccc 0110 0011 xxxx xxxx xxxx 0111 xxxx : */
1233 /* SHADD8 : cccc 0110 0011 xxxx xxxx xxxx 1001 xxxx : */
1234 /* SHSUB8 : cccc 0110 0011 xxxx xxxx xxxx 1111 xxxx : */
1235 /* UADD16 : cccc 0110 0101 xxxx xxxx xxxx 0001 xxxx :GE */
1236 /* UADDSUBX : cccc 0110 0101 xxxx xxxx xxxx 0011 xxxx :GE */
1237 /* USUBADDX : cccc 0110 0101 xxxx xxxx xxxx 0101 xxxx :GE */
1238 /* USUB16 : cccc 0110 0101 xxxx xxxx xxxx 0111 xxxx :GE */
1239 /* UADD8 : cccc 0110 0101 xxxx xxxx xxxx 1001 xxxx :GE */
1240 /* USUB8 : cccc 0110 0101 xxxx xxxx xxxx 1111 xxxx :GE */
1241 /* UQADD16 : cccc 0110 0110 xxxx xxxx xxxx 0001 xxxx : */
1242 /* UQADDSUBX : cccc 0110 0110 xxxx xxxx xxxx 0011 xxxx : */
1243 /* UQSUBADDX : cccc 0110 0110 xxxx xxxx xxxx 0101 xxxx : */
1244 /* UQSUB16 : cccc 0110 0110 xxxx xxxx xxxx 0111 xxxx : */
1245 /* UQADD8 : cccc 0110 0110 xxxx xxxx xxxx 1001 xxxx : */
1246 /* UQSUB8 : cccc 0110 0110 xxxx xxxx xxxx 1111 xxxx : */
1247 /* UHADD16 : cccc 0110 0111 xxxx xxxx xxxx 0001 xxxx : */
1248 /* UHADDSUBX : cccc 0110 0111 xxxx xxxx xxxx 0011 xxxx : */
1249 /* UHSUBADDX : cccc 0110 0111 xxxx xxxx xxxx 0101 xxxx : */
1250 /* UHSUB16 : cccc 0110 0111 xxxx xxxx xxxx 0111 xxxx : */
1251 /* UHADD8 : cccc 0110 0111 xxxx xxxx xxxx 1001 xxxx : */
1252 /* UHSUB8 : cccc 0110 0111 xxxx xxxx xxxx 1111 xxxx : */
1253 /* PKHBT : cccc 0110 1000 xxxx xxxx xxxx x001 xxxx : */
1254 /* PKHTB : cccc 0110 1000 xxxx xxxx xxxx x101 xxxx : */
1255 /* SXTAB16 : cccc 0110 1000 xxxx xxxx xxxx 0111 xxxx : */
1256 /* SXTB : cccc 0110 1010 xxxx xxxx xxxx 0111 xxxx : */
1257 /* SXTAB : cccc 0110 1010 xxxx xxxx xxxx 0111 xxxx : */
1258 /* SXTAH : cccc 0110 1011 xxxx xxxx xxxx 0111 xxxx : */
1259 /* UXTAB16 : cccc 0110 1100 xxxx xxxx xxxx 0111 xxxx : */
1260 /* UXTAB : cccc 0110 1110 xxxx xxxx xxxx 0111 xxxx : */
1261 /* UXTAH : cccc 0110 1111 xxxx xxxx xxxx 0111 xxxx : */
1262 return prep_emulate_rd12rn16rm0_wflags(insn, asi);
1263 }
1264
1265 static enum kprobe_insn __kprobes
space_cccc_0111__1(kprobe_opcode_t insn,struct arch_specific_insn * asi)1266 space_cccc_0111__1(kprobe_opcode_t insn, struct arch_specific_insn *asi)
1267 {
1268 /* Undef : cccc 0111 1111 xxxx xxxx xxxx 1111 xxxx */
1269 if ((insn & 0x0ff000f0) == 0x03f000f0)
1270 return INSN_REJECTED;
1271
1272 /* USADA8 : cccc 0111 1000 xxxx xxxx xxxx 0001 xxxx */
1273 /* USAD8 : cccc 0111 1000 xxxx 1111 xxxx 0001 xxxx */
1274 if ((insn & 0x0ff000f0) == 0x07800010)
1275 return prep_emulate_rd16rn12rs8rm0_wflags(insn, asi);
1276
1277 /* SMLALD : cccc 0111 0100 xxxx xxxx xxxx 00x1 xxxx */
1278 /* SMLSLD : cccc 0111 0100 xxxx xxxx xxxx 01x1 xxxx */
1279 if ((insn & 0x0ff00090) == 0x07400010)
1280 return prep_emulate_rdhi16rdlo12rs8rm0_wflags(insn, asi);
1281
1282 /* SMLAD : cccc 0111 0000 xxxx xxxx xxxx 00x1 xxxx :Q */
1283 /* SMLSD : cccc 0111 0000 xxxx xxxx xxxx 01x1 xxxx :Q */
1284 /* SMMLA : cccc 0111 0101 xxxx xxxx xxxx 00x1 xxxx : */
1285 /* SMMLS : cccc 0111 0101 xxxx xxxx xxxx 11x1 xxxx : */
1286 if ((insn & 0x0ff00090) == 0x07000010 ||
1287 (insn & 0x0ff000d0) == 0x07500010 ||
1288 (insn & 0x0ff000d0) == 0x075000d0)
1289 return prep_emulate_rd16rn12rs8rm0_wflags(insn, asi);
1290
1291 /* SMUSD : cccc 0111 0000 xxxx xxxx xxxx 01x1 xxxx : */
1292 /* SMUAD : cccc 0111 0000 xxxx 1111 xxxx 00x1 xxxx :Q */
1293 /* SMMUL : cccc 0111 0101 xxxx 1111 xxxx 00x1 xxxx : */
1294 return prep_emulate_rd16rs8rm0_wflags(insn, asi);
1295 }
1296
1297 static enum kprobe_insn __kprobes
space_cccc_01xx(kprobe_opcode_t insn,struct arch_specific_insn * asi)1298 space_cccc_01xx(kprobe_opcode_t insn, struct arch_specific_insn *asi)
1299 {
1300 /* LDR : cccc 01xx x0x1 xxxx xxxx xxxx xxxx xxxx */
1301 /* LDRB : cccc 01xx x1x1 xxxx xxxx xxxx xxxx xxxx */
1302 /* LDRBT : cccc 01x0 x111 xxxx xxxx xxxx xxxx xxxx */
1303 /* LDRT : cccc 01x0 x011 xxxx xxxx xxxx xxxx xxxx */
1304 /* STR : cccc 01xx x0x0 xxxx xxxx xxxx xxxx xxxx */
1305 /* STRB : cccc 01xx x1x0 xxxx xxxx xxxx xxxx xxxx */
1306 /* STRBT : cccc 01x0 x110 xxxx xxxx xxxx xxxx xxxx */
1307 /* STRT : cccc 01x0 x010 xxxx xxxx xxxx xxxx xxxx */
1308 return prep_emulate_ldr_str(insn, asi);
1309 }
1310
1311 static enum kprobe_insn __kprobes
space_cccc_100x(kprobe_opcode_t insn,struct arch_specific_insn * asi)1312 space_cccc_100x(kprobe_opcode_t insn, struct arch_specific_insn *asi)
1313 {
1314 /* LDM(2) : cccc 100x x101 xxxx 0xxx xxxx xxxx xxxx */
1315 /* LDM(3) : cccc 100x x1x1 xxxx 1xxx xxxx xxxx xxxx */
1316 if ((insn & 0x0e708000) == 0x85000000 ||
1317 (insn & 0x0e508000) == 0x85010000)
1318 return INSN_REJECTED;
1319
1320 /* LDM(1) : cccc 100x x0x1 xxxx xxxx xxxx xxxx xxxx */
1321 /* STM(1) : cccc 100x x0x0 xxxx xxxx xxxx xxxx xxxx */
1322 asi->insn[0] = truecc_insn(insn);
1323 asi->insn_handler = ((insn & 0x108000) == 0x008000) ? /* STM & R15 */
1324 simulate_stm1_pc : simulate_ldm1stm1;
1325 return INSN_GOOD;
1326 }
1327
1328 static enum kprobe_insn __kprobes
space_cccc_101x(kprobe_opcode_t insn,struct arch_specific_insn * asi)1329 space_cccc_101x(kprobe_opcode_t insn, struct arch_specific_insn *asi)
1330 {
1331 /* B : cccc 1010 xxxx xxxx xxxx xxxx xxxx xxxx */
1332 /* BL : cccc 1011 xxxx xxxx xxxx xxxx xxxx xxxx */
1333 asi->insn[0] = truecc_insn(insn);
1334 asi->insn_handler = simulate_bbl;
1335 return INSN_GOOD;
1336 }
1337
1338 static enum kprobe_insn __kprobes
space_cccc_1100_010x(kprobe_opcode_t insn,struct arch_specific_insn * asi)1339 space_cccc_1100_010x(kprobe_opcode_t insn, struct arch_specific_insn *asi)
1340 {
1341 /* MCRR : cccc 1100 0100 xxxx xxxx xxxx xxxx xxxx : (Rd!=Rn) */
1342 /* MRRC : cccc 1100 0101 xxxx xxxx xxxx xxxx xxxx : (Rd!=Rn) */
1343 insn &= 0xfff00fff;
1344 insn |= 0x00001000; /* Rn = r0, Rd = r1 */
1345 asi->insn[0] = insn;
1346 asi->insn_handler = (insn & (1 << 20)) ? emulate_mrrc : emulate_mcrr;
1347 return INSN_GOOD;
1348 }
1349
1350 static enum kprobe_insn __kprobes
space_cccc_110x(kprobe_opcode_t insn,struct arch_specific_insn * asi)1351 space_cccc_110x(kprobe_opcode_t insn, struct arch_specific_insn *asi)
1352 {
1353 /* LDC : cccc 110x xxx1 xxxx xxxx xxxx xxxx xxxx */
1354 /* STC : cccc 110x xxx0 xxxx xxxx xxxx xxxx xxxx */
1355 insn &= 0xfff0ffff; /* Rn = r0 */
1356 asi->insn[0] = insn;
1357 asi->insn_handler = emulate_ldcstc;
1358 return INSN_GOOD;
1359 }
1360
1361 static enum kprobe_insn __kprobes
space_cccc_111x(kprobe_opcode_t insn,struct arch_specific_insn * asi)1362 space_cccc_111x(kprobe_opcode_t insn, struct arch_specific_insn *asi)
1363 {
1364 /* BKPT : 1110 0001 0010 xxxx xxxx xxxx 0111 xxxx */
1365 /* SWI : cccc 1111 xxxx xxxx xxxx xxxx xxxx xxxx */
1366 if ((insn & 0xfff000f0) == 0xe1200070 ||
1367 (insn & 0x0f000000) == 0x0f000000)
1368 return INSN_REJECTED;
1369
1370 /* CDP : cccc 1110 xxxx xxxx xxxx xxxx xxx0 xxxx */
1371 if ((insn & 0x0f000010) == 0x0e000000) {
1372 asi->insn[0] = insn;
1373 asi->insn_handler = emulate_none;
1374 return INSN_GOOD;
1375 }
1376
1377 /* MCR : cccc 1110 xxx0 xxxx xxxx xxxx xxx1 xxxx */
1378 /* MRC : cccc 1110 xxx1 xxxx xxxx xxxx xxx1 xxxx */
1379 insn &= 0xffff0fff; /* Rd = r0 */
1380 asi->insn[0] = insn;
1381 asi->insn_handler = (insn & (1 << 20)) ? emulate_rd12 : emulate_ird12;
1382 return INSN_GOOD;
1383 }
1384
1385 /* Return:
1386 * INSN_REJECTED If instruction is one not allowed to kprobe,
1387 * INSN_GOOD If instruction is supported and uses instruction slot,
1388 * INSN_GOOD_NO_SLOT If instruction is supported but doesn't use its slot.
1389 *
1390 * For instructions we don't want to kprobe (INSN_REJECTED return result):
1391 * These are generally ones that modify the processor state making
1392 * them "hard" to simulate such as switches processor modes or
1393 * make accesses in alternate modes. Any of these could be simulated
1394 * if the work was put into it, but low return considering they
1395 * should also be very rare.
1396 */
1397 enum kprobe_insn __kprobes
arm_kprobe_decode_insn(kprobe_opcode_t insn,struct arch_specific_insn * asi)1398 arm_kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi)
1399 {
1400 asi->insn[1] = KPROBE_RETURN_INSTRUCTION;
1401
1402 if ((insn & 0xf0000000) == 0xf0000000) {
1403
1404 return space_1111(insn, asi);
1405
1406 } else if ((insn & 0x0e000000) == 0x00000000) {
1407
1408 return space_cccc_000x(insn, asi);
1409
1410 } else if ((insn & 0x0e000000) == 0x02000000) {
1411
1412 return space_cccc_001x(insn, asi);
1413
1414 } else if ((insn & 0x0f000010) == 0x06000010) {
1415
1416 return space_cccc_0110__1(insn, asi);
1417
1418 } else if ((insn & 0x0f000010) == 0x07000010) {
1419
1420 return space_cccc_0111__1(insn, asi);
1421
1422 } else if ((insn & 0x0c000000) == 0x04000000) {
1423
1424 return space_cccc_01xx(insn, asi);
1425
1426 } else if ((insn & 0x0e000000) == 0x08000000) {
1427
1428 return space_cccc_100x(insn, asi);
1429
1430 } else if ((insn & 0x0e000000) == 0x0a000000) {
1431
1432 return space_cccc_101x(insn, asi);
1433
1434 } else if ((insn & 0x0fe00000) == 0x0c400000) {
1435
1436 return space_cccc_1100_010x(insn, asi);
1437
1438 } else if ((insn & 0x0e000000) == 0x0c400000) {
1439
1440 return space_cccc_110x(insn, asi);
1441
1442 }
1443
1444 return space_cccc_111x(insn, asi);
1445 }
1446
arm_kprobe_decode_init(void)1447 void __init arm_kprobe_decode_init(void)
1448 {
1449 find_str_pc_offset();
1450 }
1451
1452
1453 /*
1454 * All ARM instructions listed below.
1455 *
1456 * Instructions and their general purpose registers are given.
1457 * If a particular register may not use R15, it is prefixed with a "!".
1458 * If marked with a "*" means the value returned by reading R15
1459 * is implementation defined.
1460 *
1461 * ADC/ADD/AND/BIC/CMN/CMP/EOR/MOV/MVN/ORR/RSB/RSC/SBC/SUB/TEQ
1462 * TST: Rd, Rn, Rm, !Rs
1463 * BX: Rm
1464 * BLX(2): !Rm
1465 * BX: Rm (R15 legal, but discouraged)
1466 * BXJ: !Rm,
1467 * CLZ: !Rd, !Rm
1468 * CPY: Rd, Rm
1469 * LDC/2,STC/2 immediate offset & unindex: Rn
1470 * LDC/2,STC/2 immediate pre/post-indexed: !Rn
1471 * LDM(1/3): !Rn, register_list
1472 * LDM(2): !Rn, !register_list
1473 * LDR,STR,PLD immediate offset: Rd, Rn
1474 * LDR,STR,PLD register offset: Rd, Rn, !Rm
1475 * LDR,STR,PLD scaled register offset: Rd, !Rn, !Rm
1476 * LDR,STR immediate pre/post-indexed: Rd, !Rn
1477 * LDR,STR register pre/post-indexed: Rd, !Rn, !Rm
1478 * LDR,STR scaled register pre/post-indexed: Rd, !Rn, !Rm
1479 * LDRB,STRB immediate offset: !Rd, Rn
1480 * LDRB,STRB register offset: !Rd, Rn, !Rm
1481 * LDRB,STRB scaled register offset: !Rd, !Rn, !Rm
1482 * LDRB,STRB immediate pre/post-indexed: !Rd, !Rn
1483 * LDRB,STRB register pre/post-indexed: !Rd, !Rn, !Rm
1484 * LDRB,STRB scaled register pre/post-indexed: !Rd, !Rn, !Rm
1485 * LDRT,LDRBT,STRBT immediate pre/post-indexed: !Rd, !Rn
1486 * LDRT,LDRBT,STRBT register pre/post-indexed: !Rd, !Rn, !Rm
1487 * LDRT,LDRBT,STRBT scaled register pre/post-indexed: !Rd, !Rn, !Rm
1488 * LDRH/SH/SB/D,STRH/SH/SB/D immediate offset: !Rd, Rn
1489 * LDRH/SH/SB/D,STRH/SH/SB/D register offset: !Rd, Rn, !Rm
1490 * LDRH/SH/SB/D,STRH/SH/SB/D immediate pre/post-indexed: !Rd, !Rn
1491 * LDRH/SH/SB/D,STRH/SH/SB/D register pre/post-indexed: !Rd, !Rn, !Rm
1492 * LDREX: !Rd, !Rn
1493 * MCR/2: !Rd
1494 * MCRR/2,MRRC/2: !Rd, !Rn
1495 * MLA: !Rd, !Rn, !Rm, !Rs
1496 * MOV: Rd
1497 * MRC/2: !Rd (if Rd==15, only changes cond codes, not the register)
1498 * MRS,MSR: !Rd
1499 * MUL: !Rd, !Rm, !Rs
1500 * PKH{BT,TB}: !Rd, !Rn, !Rm
1501 * QDADD,[U]QADD/16/8/SUBX: !Rd, !Rm, !Rn
1502 * QDSUB,[U]QSUB/16/8/ADDX: !Rd, !Rm, !Rn
1503 * REV/16/SH: !Rd, !Rm
1504 * RFE: !Rn
1505 * {S,U}[H]ADD{16,8,SUBX},{S,U}[H]SUB{16,8,ADDX}: !Rd, !Rn, !Rm
1506 * SEL: !Rd, !Rn, !Rm
1507 * SMLA<x><y>,SMLA{D,W<y>},SMLSD,SMML{A,S}: !Rd, !Rn, !Rm, !Rs
1508 * SMLAL<x><y>,SMLA{D,LD},SMLSLD,SMMULL,SMULW<y>: !RdHi, !RdLo, !Rm, !Rs
1509 * SMMUL,SMUAD,SMUL<x><y>,SMUSD: !Rd, !Rm, !Rs
1510 * SSAT/16: !Rd, !Rm
1511 * STM(1/2): !Rn, register_list* (R15 in reg list not recommended)
1512 * STRT immediate pre/post-indexed: Rd*, !Rn
1513 * STRT register pre/post-indexed: Rd*, !Rn, !Rm
1514 * STRT scaled register pre/post-indexed: Rd*, !Rn, !Rm
1515 * STREX: !Rd, !Rn, !Rm
1516 * SWP/B: !Rd, !Rn, !Rm
1517 * {S,U}XTA{B,B16,H}: !Rd, !Rn, !Rm
1518 * {S,U}XT{B,B16,H}: !Rd, !Rm
1519 * UM{AA,LA,UL}L: !RdHi, !RdLo, !Rm, !Rs
1520 * USA{D8,A8,T,T16}: !Rd, !Rm, !Rs
1521 *
1522 * May transfer control by writing R15 (possible mode changes or alternate
1523 * mode accesses marked by "*"):
1524 * ALU op (* with s-bit), B, BL, BKPT, BLX(1/2), BX, BXJ, CPS*, CPY,
1525 * LDM(1), LDM(2/3)*, LDR, MOV, RFE*, SWI*
1526 *
1527 * Instructions that do not take general registers, nor transfer control:
1528 * CDP/2, SETEND, SRS*
1529 */
1530