1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * arch/arm/probes/kprobes/actions-thumb.c
4 *
5 * Copyright (C) 2011 Jon Medhurst <tixy@yxit.co.uk>.
6 */
7
8 #include <linux/types.h>
9 #include <linux/kernel.h>
10 #include <linux/ptrace.h>
11 #include <linux/kprobes.h>
12
13 #include "../decode-thumb.h"
14 #include "core.h"
15 #include "checkers.h"
16
17 /* These emulation encodings are functionally equivalent... */
18 #define t32_emulate_rd8rn16rm0ra12_noflags \
19 t32_emulate_rdlo12rdhi8rn16rm0_noflags
20
21 /* t32 thumb actions */
22
23 static void __kprobes
t32_simulate_table_branch(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)24 t32_simulate_table_branch(probes_opcode_t insn,
25 struct arch_probes_insn *asi, struct pt_regs *regs)
26 {
27 unsigned long pc = regs->ARM_pc;
28 int rn = (insn >> 16) & 0xf;
29 int rm = insn & 0xf;
30
31 unsigned long rnv = (rn == 15) ? pc : regs->uregs[rn];
32 unsigned long rmv = regs->uregs[rm];
33 unsigned int halfwords;
34
35 if (insn & 0x10) /* TBH */
36 halfwords = ((u16 *)rnv)[rmv];
37 else /* TBB */
38 halfwords = ((u8 *)rnv)[rmv];
39
40 regs->ARM_pc = pc + 2 * halfwords;
41 }
42
43 static void __kprobes
t32_simulate_mrs(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)44 t32_simulate_mrs(probes_opcode_t insn,
45 struct arch_probes_insn *asi, struct pt_regs *regs)
46 {
47 int rd = (insn >> 8) & 0xf;
48 unsigned long mask = 0xf8ff03df; /* Mask out execution state */
49 regs->uregs[rd] = regs->ARM_cpsr & mask;
50 }
51
52 static void __kprobes
t32_simulate_cond_branch(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)53 t32_simulate_cond_branch(probes_opcode_t insn,
54 struct arch_probes_insn *asi, struct pt_regs *regs)
55 {
56 unsigned long pc = regs->ARM_pc;
57
58 long offset = insn & 0x7ff; /* imm11 */
59 offset += (insn & 0x003f0000) >> 5; /* imm6 */
60 offset += (insn & 0x00002000) << 4; /* J1 */
61 offset += (insn & 0x00000800) << 7; /* J2 */
62 offset -= (insn & 0x04000000) >> 7; /* Apply sign bit */
63
64 regs->ARM_pc = pc + (offset * 2);
65 }
66
67 static enum probes_insn __kprobes
t32_decode_cond_branch(probes_opcode_t insn,struct arch_probes_insn * asi,const struct decode_header * d)68 t32_decode_cond_branch(probes_opcode_t insn, struct arch_probes_insn *asi,
69 const struct decode_header *d)
70 {
71 int cc = (insn >> 22) & 0xf;
72 asi->insn_check_cc = probes_condition_checks[cc];
73 asi->insn_handler = t32_simulate_cond_branch;
74 return INSN_GOOD_NO_SLOT;
75 }
76
77 static void __kprobes
t32_simulate_branch(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)78 t32_simulate_branch(probes_opcode_t insn,
79 struct arch_probes_insn *asi, struct pt_regs *regs)
80 {
81 unsigned long pc = regs->ARM_pc;
82
83 long offset = insn & 0x7ff; /* imm11 */
84 offset += (insn & 0x03ff0000) >> 5; /* imm10 */
85 offset += (insn & 0x00002000) << 9; /* J1 */
86 offset += (insn & 0x00000800) << 10; /* J2 */
87 if (insn & 0x04000000)
88 offset -= 0x00800000; /* Apply sign bit */
89 else
90 offset ^= 0x00600000; /* Invert J1 and J2 */
91
92 if (insn & (1 << 14)) {
93 /* BL or BLX */
94 regs->ARM_lr = regs->ARM_pc | 1;
95 if (!(insn & (1 << 12))) {
96 /* BLX so switch to ARM mode */
97 regs->ARM_cpsr &= ~PSR_T_BIT;
98 pc &= ~3;
99 }
100 }
101
102 regs->ARM_pc = pc + (offset * 2);
103 }
104
105 static void __kprobes
t32_simulate_ldr_literal(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)106 t32_simulate_ldr_literal(probes_opcode_t insn,
107 struct arch_probes_insn *asi, struct pt_regs *regs)
108 {
109 unsigned long addr = regs->ARM_pc & ~3;
110 int rt = (insn >> 12) & 0xf;
111 unsigned long rtv;
112
113 long offset = insn & 0xfff;
114 if (insn & 0x00800000)
115 addr += offset;
116 else
117 addr -= offset;
118
119 if (insn & 0x00400000) {
120 /* LDR */
121 rtv = *(unsigned long *)addr;
122 if (rt == 15) {
123 bx_write_pc(rtv, regs);
124 return;
125 }
126 } else if (insn & 0x00200000) {
127 /* LDRH */
128 if (insn & 0x01000000)
129 rtv = *(s16 *)addr;
130 else
131 rtv = *(u16 *)addr;
132 } else {
133 /* LDRB */
134 if (insn & 0x01000000)
135 rtv = *(s8 *)addr;
136 else
137 rtv = *(u8 *)addr;
138 }
139
140 regs->uregs[rt] = rtv;
141 }
142
143 static enum probes_insn __kprobes
t32_decode_ldmstm(probes_opcode_t insn,struct arch_probes_insn * asi,const struct decode_header * d)144 t32_decode_ldmstm(probes_opcode_t insn, struct arch_probes_insn *asi,
145 const struct decode_header *d)
146 {
147 enum probes_insn ret = kprobe_decode_ldmstm(insn, asi, d);
148
149 /* Fixup modified instruction to have halfwords in correct order...*/
150 insn = __mem_to_opcode_arm(asi->insn[0]);
151 ((u16 *)asi->insn)[0] = __opcode_to_mem_thumb16(insn >> 16);
152 ((u16 *)asi->insn)[1] = __opcode_to_mem_thumb16(insn & 0xffff);
153
154 return ret;
155 }
156
157 static void __kprobes
t32_emulate_ldrdstrd(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)158 t32_emulate_ldrdstrd(probes_opcode_t insn,
159 struct arch_probes_insn *asi, struct pt_regs *regs)
160 {
161 unsigned long pc = regs->ARM_pc & ~3;
162 int rt1 = (insn >> 12) & 0xf;
163 int rt2 = (insn >> 8) & 0xf;
164 int rn = (insn >> 16) & 0xf;
165
166 register unsigned long rt1v asm("r0") = regs->uregs[rt1];
167 register unsigned long rt2v asm("r1") = regs->uregs[rt2];
168 register unsigned long rnv asm("r2") = (rn == 15) ? pc
169 : regs->uregs[rn];
170
171 __asm__ __volatile__ (
172 "blx %[fn]"
173 : "=r" (rt1v), "=r" (rt2v), "=r" (rnv)
174 : "0" (rt1v), "1" (rt2v), "2" (rnv), [fn] "r" (asi->insn_fn)
175 : "lr", "memory", "cc"
176 );
177
178 if (rn != 15)
179 regs->uregs[rn] = rnv; /* Writeback base register */
180 regs->uregs[rt1] = rt1v;
181 regs->uregs[rt2] = rt2v;
182 }
183
184 static void __kprobes
t32_emulate_ldrstr(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)185 t32_emulate_ldrstr(probes_opcode_t insn,
186 struct arch_probes_insn *asi, struct pt_regs *regs)
187 {
188 int rt = (insn >> 12) & 0xf;
189 int rn = (insn >> 16) & 0xf;
190 int rm = insn & 0xf;
191
192 register unsigned long rtv asm("r0") = regs->uregs[rt];
193 register unsigned long rnv asm("r2") = regs->uregs[rn];
194 register unsigned long rmv asm("r3") = regs->uregs[rm];
195
196 __asm__ __volatile__ (
197 "blx %[fn]"
198 : "=r" (rtv), "=r" (rnv)
199 : "0" (rtv), "1" (rnv), "r" (rmv), [fn] "r" (asi->insn_fn)
200 : "lr", "memory", "cc"
201 );
202
203 regs->uregs[rn] = rnv; /* Writeback base register */
204 if (rt == 15) /* Can't be true for a STR as they aren't allowed */
205 bx_write_pc(rtv, regs);
206 else
207 regs->uregs[rt] = rtv;
208 }
209
210 static void __kprobes
t32_emulate_rd8rn16rm0_rwflags(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)211 t32_emulate_rd8rn16rm0_rwflags(probes_opcode_t insn,
212 struct arch_probes_insn *asi, struct pt_regs *regs)
213 {
214 int rd = (insn >> 8) & 0xf;
215 int rn = (insn >> 16) & 0xf;
216 int rm = insn & 0xf;
217
218 register unsigned long rdv asm("r1") = regs->uregs[rd];
219 register unsigned long rnv asm("r2") = regs->uregs[rn];
220 register unsigned long rmv asm("r3") = regs->uregs[rm];
221 unsigned long cpsr = regs->ARM_cpsr;
222
223 __asm__ __volatile__ (
224 "msr cpsr_fs, %[cpsr] \n\t"
225 "blx %[fn] \n\t"
226 "mrs %[cpsr], cpsr \n\t"
227 : "=r" (rdv), [cpsr] "=r" (cpsr)
228 : "0" (rdv), "r" (rnv), "r" (rmv),
229 "1" (cpsr), [fn] "r" (asi->insn_fn)
230 : "lr", "memory", "cc"
231 );
232
233 regs->uregs[rd] = rdv;
234 regs->ARM_cpsr = (regs->ARM_cpsr & ~APSR_MASK) | (cpsr & APSR_MASK);
235 }
236
237 static void __kprobes
t32_emulate_rd8pc16_noflags(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)238 t32_emulate_rd8pc16_noflags(probes_opcode_t insn,
239 struct arch_probes_insn *asi, struct pt_regs *regs)
240 {
241 unsigned long pc = regs->ARM_pc;
242 int rd = (insn >> 8) & 0xf;
243
244 register unsigned long rdv asm("r1") = regs->uregs[rd];
245 register unsigned long rnv asm("r2") = pc & ~3;
246
247 __asm__ __volatile__ (
248 "blx %[fn]"
249 : "=r" (rdv)
250 : "0" (rdv), "r" (rnv), [fn] "r" (asi->insn_fn)
251 : "lr", "memory", "cc"
252 );
253
254 regs->uregs[rd] = rdv;
255 }
256
257 static void __kprobes
t32_emulate_rd8rn16_noflags(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)258 t32_emulate_rd8rn16_noflags(probes_opcode_t insn,
259 struct arch_probes_insn *asi, struct pt_regs *regs)
260 {
261 int rd = (insn >> 8) & 0xf;
262 int rn = (insn >> 16) & 0xf;
263
264 register unsigned long rdv asm("r1") = regs->uregs[rd];
265 register unsigned long rnv asm("r2") = regs->uregs[rn];
266
267 __asm__ __volatile__ (
268 "blx %[fn]"
269 : "=r" (rdv)
270 : "0" (rdv), "r" (rnv), [fn] "r" (asi->insn_fn)
271 : "lr", "memory", "cc"
272 );
273
274 regs->uregs[rd] = rdv;
275 }
276
277 static void __kprobes
t32_emulate_rdlo12rdhi8rn16rm0_noflags(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)278 t32_emulate_rdlo12rdhi8rn16rm0_noflags(probes_opcode_t insn,
279 struct arch_probes_insn *asi,
280 struct pt_regs *regs)
281 {
282 int rdlo = (insn >> 12) & 0xf;
283 int rdhi = (insn >> 8) & 0xf;
284 int rn = (insn >> 16) & 0xf;
285 int rm = insn & 0xf;
286
287 register unsigned long rdlov asm("r0") = regs->uregs[rdlo];
288 register unsigned long rdhiv asm("r1") = regs->uregs[rdhi];
289 register unsigned long rnv asm("r2") = regs->uregs[rn];
290 register unsigned long rmv asm("r3") = regs->uregs[rm];
291
292 __asm__ __volatile__ (
293 "blx %[fn]"
294 : "=r" (rdlov), "=r" (rdhiv)
295 : "0" (rdlov), "1" (rdhiv), "r" (rnv), "r" (rmv),
296 [fn] "r" (asi->insn_fn)
297 : "lr", "memory", "cc"
298 );
299
300 regs->uregs[rdlo] = rdlov;
301 regs->uregs[rdhi] = rdhiv;
302 }
303 /* t16 thumb actions */
304
305 static void __kprobes
t16_simulate_bxblx(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)306 t16_simulate_bxblx(probes_opcode_t insn,
307 struct arch_probes_insn *asi, struct pt_regs *regs)
308 {
309 unsigned long pc = regs->ARM_pc + 2;
310 int rm = (insn >> 3) & 0xf;
311 unsigned long rmv = (rm == 15) ? pc : regs->uregs[rm];
312
313 if (insn & (1 << 7)) /* BLX ? */
314 regs->ARM_lr = regs->ARM_pc | 1;
315
316 bx_write_pc(rmv, regs);
317 }
318
319 static void __kprobes
t16_simulate_ldr_literal(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)320 t16_simulate_ldr_literal(probes_opcode_t insn,
321 struct arch_probes_insn *asi, struct pt_regs *regs)
322 {
323 unsigned long *base = (unsigned long *)((regs->ARM_pc + 2) & ~3);
324 long index = insn & 0xff;
325 int rt = (insn >> 8) & 0x7;
326 regs->uregs[rt] = base[index];
327 }
328
329 static void __kprobes
t16_simulate_ldrstr_sp_relative(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)330 t16_simulate_ldrstr_sp_relative(probes_opcode_t insn,
331 struct arch_probes_insn *asi, struct pt_regs *regs)
332 {
333 unsigned long* base = (unsigned long *)regs->ARM_sp;
334 long index = insn & 0xff;
335 int rt = (insn >> 8) & 0x7;
336 if (insn & 0x800) /* LDR */
337 regs->uregs[rt] = base[index];
338 else /* STR */
339 base[index] = regs->uregs[rt];
340 }
341
342 static void __kprobes
t16_simulate_reladr(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)343 t16_simulate_reladr(probes_opcode_t insn,
344 struct arch_probes_insn *asi, struct pt_regs *regs)
345 {
346 unsigned long base = (insn & 0x800) ? regs->ARM_sp
347 : ((regs->ARM_pc + 2) & ~3);
348 long offset = insn & 0xff;
349 int rt = (insn >> 8) & 0x7;
350 regs->uregs[rt] = base + offset * 4;
351 }
352
353 static void __kprobes
t16_simulate_add_sp_imm(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)354 t16_simulate_add_sp_imm(probes_opcode_t insn,
355 struct arch_probes_insn *asi, struct pt_regs *regs)
356 {
357 long imm = insn & 0x7f;
358 if (insn & 0x80) /* SUB */
359 regs->ARM_sp -= imm * 4;
360 else /* ADD */
361 regs->ARM_sp += imm * 4;
362 }
363
364 static void __kprobes
t16_simulate_cbz(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)365 t16_simulate_cbz(probes_opcode_t insn,
366 struct arch_probes_insn *asi, struct pt_regs *regs)
367 {
368 int rn = insn & 0x7;
369 probes_opcode_t nonzero = regs->uregs[rn] ? insn : ~insn;
370 if (nonzero & 0x800) {
371 long i = insn & 0x200;
372 long imm5 = insn & 0xf8;
373 unsigned long pc = regs->ARM_pc + 2;
374 regs->ARM_pc = pc + (i >> 3) + (imm5 >> 2);
375 }
376 }
377
378 static void __kprobes
t16_simulate_it(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)379 t16_simulate_it(probes_opcode_t insn,
380 struct arch_probes_insn *asi, struct pt_regs *regs)
381 {
382 /*
383 * The 8 IT state bits are split into two parts in CPSR:
384 * ITSTATE<1:0> are in CPSR<26:25>
385 * ITSTATE<7:2> are in CPSR<15:10>
386 * The new IT state is in the lower byte of insn.
387 */
388 unsigned long cpsr = regs->ARM_cpsr;
389 cpsr &= ~PSR_IT_MASK;
390 cpsr |= (insn & 0xfc) << 8;
391 cpsr |= (insn & 0x03) << 25;
392 regs->ARM_cpsr = cpsr;
393 }
394
395 static void __kprobes
t16_singlestep_it(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)396 t16_singlestep_it(probes_opcode_t insn,
397 struct arch_probes_insn *asi, struct pt_regs *regs)
398 {
399 regs->ARM_pc += 2;
400 t16_simulate_it(insn, asi, regs);
401 }
402
403 static enum probes_insn __kprobes
t16_decode_it(probes_opcode_t insn,struct arch_probes_insn * asi,const struct decode_header * d)404 t16_decode_it(probes_opcode_t insn, struct arch_probes_insn *asi,
405 const struct decode_header *d)
406 {
407 asi->insn_singlestep = t16_singlestep_it;
408 return INSN_GOOD_NO_SLOT;
409 }
410
411 static void __kprobes
t16_simulate_cond_branch(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)412 t16_simulate_cond_branch(probes_opcode_t insn,
413 struct arch_probes_insn *asi, struct pt_regs *regs)
414 {
415 unsigned long pc = regs->ARM_pc + 2;
416 long offset = insn & 0x7f;
417 offset -= insn & 0x80; /* Apply sign bit */
418 regs->ARM_pc = pc + (offset * 2);
419 }
420
421 static enum probes_insn __kprobes
t16_decode_cond_branch(probes_opcode_t insn,struct arch_probes_insn * asi,const struct decode_header * d)422 t16_decode_cond_branch(probes_opcode_t insn, struct arch_probes_insn *asi,
423 const struct decode_header *d)
424 {
425 int cc = (insn >> 8) & 0xf;
426 asi->insn_check_cc = probes_condition_checks[cc];
427 asi->insn_handler = t16_simulate_cond_branch;
428 return INSN_GOOD_NO_SLOT;
429 }
430
431 static void __kprobes
t16_simulate_branch(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)432 t16_simulate_branch(probes_opcode_t insn,
433 struct arch_probes_insn *asi, struct pt_regs *regs)
434 {
435 unsigned long pc = regs->ARM_pc + 2;
436 long offset = insn & 0x3ff;
437 offset -= insn & 0x400; /* Apply sign bit */
438 regs->ARM_pc = pc + (offset * 2);
439 }
440
441 static unsigned long __kprobes
t16_emulate_loregs(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)442 t16_emulate_loregs(probes_opcode_t insn,
443 struct arch_probes_insn *asi, struct pt_regs *regs)
444 {
445 unsigned long oldcpsr = regs->ARM_cpsr;
446 unsigned long newcpsr;
447
448 __asm__ __volatile__ (
449 "msr cpsr_fs, %[oldcpsr] \n\t"
450 "ldmia %[regs], {r0-r7} \n\t"
451 "blx %[fn] \n\t"
452 "stmia %[regs], {r0-r7} \n\t"
453 "mrs %[newcpsr], cpsr \n\t"
454 : [newcpsr] "=r" (newcpsr)
455 : [oldcpsr] "r" (oldcpsr), [regs] "r" (regs),
456 [fn] "r" (asi->insn_fn)
457 : "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
458 "lr", "memory", "cc"
459 );
460
461 return (oldcpsr & ~APSR_MASK) | (newcpsr & APSR_MASK);
462 }
463
464 static void __kprobes
t16_emulate_loregs_rwflags(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)465 t16_emulate_loregs_rwflags(probes_opcode_t insn,
466 struct arch_probes_insn *asi, struct pt_regs *regs)
467 {
468 regs->ARM_cpsr = t16_emulate_loregs(insn, asi, regs);
469 }
470
471 static void __kprobes
t16_emulate_loregs_noitrwflags(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)472 t16_emulate_loregs_noitrwflags(probes_opcode_t insn,
473 struct arch_probes_insn *asi, struct pt_regs *regs)
474 {
475 unsigned long cpsr = t16_emulate_loregs(insn, asi, regs);
476 if (!in_it_block(cpsr))
477 regs->ARM_cpsr = cpsr;
478 }
479
480 static void __kprobes
t16_emulate_hiregs(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)481 t16_emulate_hiregs(probes_opcode_t insn,
482 struct arch_probes_insn *asi, struct pt_regs *regs)
483 {
484 unsigned long pc = regs->ARM_pc + 2;
485 int rdn = (insn & 0x7) | ((insn & 0x80) >> 4);
486 int rm = (insn >> 3) & 0xf;
487
488 register unsigned long rdnv asm("r1");
489 register unsigned long rmv asm("r0");
490 unsigned long cpsr = regs->ARM_cpsr;
491
492 rdnv = (rdn == 15) ? pc : regs->uregs[rdn];
493 rmv = (rm == 15) ? pc : regs->uregs[rm];
494
495 __asm__ __volatile__ (
496 "msr cpsr_fs, %[cpsr] \n\t"
497 "blx %[fn] \n\t"
498 "mrs %[cpsr], cpsr \n\t"
499 : "=r" (rdnv), [cpsr] "=r" (cpsr)
500 : "0" (rdnv), "r" (rmv), "1" (cpsr), [fn] "r" (asi->insn_fn)
501 : "lr", "memory", "cc"
502 );
503
504 if (rdn == 15)
505 rdnv &= ~1;
506
507 regs->uregs[rdn] = rdnv;
508 regs->ARM_cpsr = (regs->ARM_cpsr & ~APSR_MASK) | (cpsr & APSR_MASK);
509 }
510
511 static enum probes_insn __kprobes
t16_decode_hiregs(probes_opcode_t insn,struct arch_probes_insn * asi,const struct decode_header * d)512 t16_decode_hiregs(probes_opcode_t insn, struct arch_probes_insn *asi,
513 const struct decode_header *d)
514 {
515 insn &= ~0x00ff;
516 insn |= 0x001; /* Set Rdn = R1 and Rm = R0 */
517 ((u16 *)asi->insn)[0] = __opcode_to_mem_thumb16(insn);
518 asi->insn_handler = t16_emulate_hiregs;
519 return INSN_GOOD;
520 }
521
522 static void __kprobes
t16_emulate_push(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)523 t16_emulate_push(probes_opcode_t insn,
524 struct arch_probes_insn *asi, struct pt_regs *regs)
525 {
526 __asm__ __volatile__ (
527 "ldr r9, [%[regs], #13*4] \n\t"
528 "ldr r8, [%[regs], #14*4] \n\t"
529 "ldmia %[regs], {r0-r7} \n\t"
530 "blx %[fn] \n\t"
531 "str r9, [%[regs], #13*4] \n\t"
532 :
533 : [regs] "r" (regs), [fn] "r" (asi->insn_fn)
534 : "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", "r8", "r9",
535 "lr", "memory", "cc"
536 );
537 }
538
539 static enum probes_insn __kprobes
t16_decode_push(probes_opcode_t insn,struct arch_probes_insn * asi,const struct decode_header * d)540 t16_decode_push(probes_opcode_t insn, struct arch_probes_insn *asi,
541 const struct decode_header *d)
542 {
543 /*
544 * To simulate a PUSH we use a Thumb-2 "STMDB R9!, {registers}"
545 * and call it with R9=SP and LR in the register list represented
546 * by R8.
547 */
548 /* 1st half STMDB R9!,{} */
549 ((u16 *)asi->insn)[0] = __opcode_to_mem_thumb16(0xe929);
550 /* 2nd half (register list) */
551 ((u16 *)asi->insn)[1] = __opcode_to_mem_thumb16(insn & 0x1ff);
552 asi->insn_handler = t16_emulate_push;
553 return INSN_GOOD;
554 }
555
556 static void __kprobes
t16_emulate_pop_nopc(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)557 t16_emulate_pop_nopc(probes_opcode_t insn,
558 struct arch_probes_insn *asi, struct pt_regs *regs)
559 {
560 __asm__ __volatile__ (
561 "ldr r9, [%[regs], #13*4] \n\t"
562 "ldmia %[regs], {r0-r7} \n\t"
563 "blx %[fn] \n\t"
564 "stmia %[regs], {r0-r7} \n\t"
565 "str r9, [%[regs], #13*4] \n\t"
566 :
567 : [regs] "r" (regs), [fn] "r" (asi->insn_fn)
568 : "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", "r9",
569 "lr", "memory", "cc"
570 );
571 }
572
573 static void __kprobes
t16_emulate_pop_pc(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)574 t16_emulate_pop_pc(probes_opcode_t insn,
575 struct arch_probes_insn *asi, struct pt_regs *regs)
576 {
577 register unsigned long pc asm("r8");
578
579 __asm__ __volatile__ (
580 "ldr r9, [%[regs], #13*4] \n\t"
581 "ldmia %[regs], {r0-r7} \n\t"
582 "blx %[fn] \n\t"
583 "stmia %[regs], {r0-r7} \n\t"
584 "str r9, [%[regs], #13*4] \n\t"
585 : "=r" (pc)
586 : [regs] "r" (regs), [fn] "r" (asi->insn_fn)
587 : "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", "r9",
588 "lr", "memory", "cc"
589 );
590
591 bx_write_pc(pc, regs);
592 }
593
594 static enum probes_insn __kprobes
t16_decode_pop(probes_opcode_t insn,struct arch_probes_insn * asi,const struct decode_header * d)595 t16_decode_pop(probes_opcode_t insn, struct arch_probes_insn *asi,
596 const struct decode_header *d)
597 {
598 /*
599 * To simulate a POP we use a Thumb-2 "LDMDB R9!, {registers}"
600 * and call it with R9=SP and PC in the register list represented
601 * by R8.
602 */
603 /* 1st half LDMIA R9!,{} */
604 ((u16 *)asi->insn)[0] = __opcode_to_mem_thumb16(0xe8b9);
605 /* 2nd half (register list) */
606 ((u16 *)asi->insn)[1] = __opcode_to_mem_thumb16(insn & 0x1ff);
607 asi->insn_handler = insn & 0x100 ? t16_emulate_pop_pc
608 : t16_emulate_pop_nopc;
609 return INSN_GOOD;
610 }
611
612 const union decode_action kprobes_t16_actions[NUM_PROBES_T16_ACTIONS] = {
613 [PROBES_T16_ADD_SP] = {.handler = t16_simulate_add_sp_imm},
614 [PROBES_T16_CBZ] = {.handler = t16_simulate_cbz},
615 [PROBES_T16_SIGN_EXTEND] = {.handler = t16_emulate_loregs_rwflags},
616 [PROBES_T16_PUSH] = {.decoder = t16_decode_push},
617 [PROBES_T16_POP] = {.decoder = t16_decode_pop},
618 [PROBES_T16_SEV] = {.handler = probes_emulate_none},
619 [PROBES_T16_WFE] = {.handler = probes_simulate_nop},
620 [PROBES_T16_IT] = {.decoder = t16_decode_it},
621 [PROBES_T16_CMP] = {.handler = t16_emulate_loregs_rwflags},
622 [PROBES_T16_ADDSUB] = {.handler = t16_emulate_loregs_noitrwflags},
623 [PROBES_T16_LOGICAL] = {.handler = t16_emulate_loregs_noitrwflags},
624 [PROBES_T16_LDR_LIT] = {.handler = t16_simulate_ldr_literal},
625 [PROBES_T16_BLX] = {.handler = t16_simulate_bxblx},
626 [PROBES_T16_HIREGOPS] = {.decoder = t16_decode_hiregs},
627 [PROBES_T16_LDRHSTRH] = {.handler = t16_emulate_loregs_rwflags},
628 [PROBES_T16_LDRSTR] = {.handler = t16_simulate_ldrstr_sp_relative},
629 [PROBES_T16_ADR] = {.handler = t16_simulate_reladr},
630 [PROBES_T16_LDMSTM] = {.handler = t16_emulate_loregs_rwflags},
631 [PROBES_T16_BRANCH_COND] = {.decoder = t16_decode_cond_branch},
632 [PROBES_T16_BRANCH] = {.handler = t16_simulate_branch},
633 };
634
635 const union decode_action kprobes_t32_actions[NUM_PROBES_T32_ACTIONS] = {
636 [PROBES_T32_LDMSTM] = {.decoder = t32_decode_ldmstm},
637 [PROBES_T32_LDRDSTRD] = {.handler = t32_emulate_ldrdstrd},
638 [PROBES_T32_TABLE_BRANCH] = {.handler = t32_simulate_table_branch},
639 [PROBES_T32_TST] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
640 [PROBES_T32_MOV] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
641 [PROBES_T32_ADDSUB] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
642 [PROBES_T32_LOGICAL] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
643 [PROBES_T32_CMP] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
644 [PROBES_T32_ADDWSUBW_PC] = {.handler = t32_emulate_rd8pc16_noflags,},
645 [PROBES_T32_ADDWSUBW] = {.handler = t32_emulate_rd8rn16_noflags},
646 [PROBES_T32_MOVW] = {.handler = t32_emulate_rd8rn16_noflags},
647 [PROBES_T32_SAT] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
648 [PROBES_T32_BITFIELD] = {.handler = t32_emulate_rd8rn16_noflags},
649 [PROBES_T32_SEV] = {.handler = probes_emulate_none},
650 [PROBES_T32_WFE] = {.handler = probes_simulate_nop},
651 [PROBES_T32_MRS] = {.handler = t32_simulate_mrs},
652 [PROBES_T32_BRANCH_COND] = {.decoder = t32_decode_cond_branch},
653 [PROBES_T32_BRANCH] = {.handler = t32_simulate_branch},
654 [PROBES_T32_PLDI] = {.handler = probes_simulate_nop},
655 [PROBES_T32_LDR_LIT] = {.handler = t32_simulate_ldr_literal},
656 [PROBES_T32_LDRSTR] = {.handler = t32_emulate_ldrstr},
657 [PROBES_T32_SIGN_EXTEND] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
658 [PROBES_T32_MEDIA] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
659 [PROBES_T32_REVERSE] = {.handler = t32_emulate_rd8rn16_noflags},
660 [PROBES_T32_MUL_ADD] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
661 [PROBES_T32_MUL_ADD2] = {.handler = t32_emulate_rd8rn16rm0ra12_noflags},
662 [PROBES_T32_MUL_ADD_LONG] = {
663 .handler = t32_emulate_rdlo12rdhi8rn16rm0_noflags},
664 };
665
666 const struct decode_checker *kprobes_t32_checkers[] = {t32_stack_checker, NULL};
667 const struct decode_checker *kprobes_t16_checkers[] = {t16_stack_checker, NULL};
668