1 /*
2 *
3 * arch/arm/probes/decode-arm.c
4 *
5 * Some code moved here from arch/arm/kernel/kprobes-arm.c
6 *
7 * Copyright (C) 2006, 2007 Motorola Inc.
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * General Public License for more details.
17 */
18
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/stddef.h>
22 #include <linux/ptrace.h>
23
24 #include "decode.h"
25 #include "decode-arm.h"
26
27 #define sign_extend(x, signbit) ((x) | (0 - ((x) & (1 << (signbit)))))
28
29 #define branch_displacement(insn) sign_extend(((insn) & 0xffffff) << 2, 25)
30
31 /*
32 * To avoid the complications of mimicing single-stepping on a
33 * processor without a Next-PC or a single-step mode, and to
34 * avoid having to deal with the side-effects of boosting, we
35 * simulate or emulate (almost) all ARM instructions.
36 *
37 * "Simulation" is where the instruction's behavior is duplicated in
38 * C code. "Emulation" is where the original instruction is rewritten
39 * and executed, often by altering its registers.
40 *
41 * By having all behavior of the kprobe'd instruction completed before
42 * returning from the kprobe_handler(), all locks (scheduler and
43 * interrupt) can safely be released. There is no need for secondary
44 * breakpoints, no race with MP or preemptable kernels, nor having to
45 * clean up resources counts at a later time impacting overall system
46 * performance. By rewriting the instruction, only the minimum registers
47 * need to be loaded and saved back optimizing performance.
48 *
49 * Calling the insnslot_*_rwflags version of a function doesn't hurt
50 * anything even when the CPSR flags aren't updated by the
51 * instruction. It's just a little slower in return for saving
52 * a little space by not having a duplicate function that doesn't
53 * update the flags. (The same optimization can be said for
54 * instructions that do or don't perform register writeback)
55 * Also, instructions can either read the flags, only write the
56 * flags, or read and write the flags. To save combinations
57 * rather than for sheer performance, flag functions just assume
58 * read and write of flags.
59 */
60
simulate_bbl(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)61 void __kprobes simulate_bbl(probes_opcode_t insn,
62 struct arch_probes_insn *asi, struct pt_regs *regs)
63 {
64 long iaddr = (long) regs->ARM_pc - 4;
65 int disp = branch_displacement(insn);
66
67 if (insn & (1 << 24))
68 regs->ARM_lr = iaddr + 4;
69
70 regs->ARM_pc = iaddr + 8 + disp;
71 }
72
simulate_blx1(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)73 void __kprobes simulate_blx1(probes_opcode_t insn,
74 struct arch_probes_insn *asi, struct pt_regs *regs)
75 {
76 long iaddr = (long) regs->ARM_pc - 4;
77 int disp = branch_displacement(insn);
78
79 regs->ARM_lr = iaddr + 4;
80 regs->ARM_pc = iaddr + 8 + disp + ((insn >> 23) & 0x2);
81 regs->ARM_cpsr |= PSR_T_BIT;
82 }
83
simulate_blx2bx(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)84 void __kprobes simulate_blx2bx(probes_opcode_t insn,
85 struct arch_probes_insn *asi, struct pt_regs *regs)
86 {
87 int rm = insn & 0xf;
88 long rmv = regs->uregs[rm];
89
90 if (insn & (1 << 5))
91 regs->ARM_lr = (long) regs->ARM_pc;
92
93 regs->ARM_pc = rmv & ~0x1;
94 regs->ARM_cpsr &= ~PSR_T_BIT;
95 if (rmv & 0x1)
96 regs->ARM_cpsr |= PSR_T_BIT;
97 }
98
simulate_mrs(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)99 void __kprobes simulate_mrs(probes_opcode_t insn,
100 struct arch_probes_insn *asi, struct pt_regs *regs)
101 {
102 int rd = (insn >> 12) & 0xf;
103 unsigned long mask = 0xf8ff03df; /* Mask out execution state */
104 regs->uregs[rd] = regs->ARM_cpsr & mask;
105 }
106
simulate_mov_ipsp(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)107 void __kprobes simulate_mov_ipsp(probes_opcode_t insn,
108 struct arch_probes_insn *asi, struct pt_regs *regs)
109 {
110 regs->uregs[12] = regs->uregs[13];
111 }
112
113 /*
114 * For the instruction masking and comparisons in all the "space_*"
115 * functions below, Do _not_ rearrange the order of tests unless
116 * you're very, very sure of what you are doing. For the sake of
117 * efficiency, the masks for some tests sometimes assume other test
118 * have been done prior to them so the number of patterns to test
119 * for an instruction set can be as broad as possible to reduce the
120 * number of tests needed.
121 */
122
123 static const union decode_item arm_1111_table[] = {
124 /* Unconditional instructions */
125
126 /* memory hint 1111 0100 x001 xxxx xxxx xxxx xxxx xxxx */
127 /* PLDI (immediate) 1111 0100 x101 xxxx xxxx xxxx xxxx xxxx */
128 /* PLDW (immediate) 1111 0101 x001 xxxx xxxx xxxx xxxx xxxx */
129 /* PLD (immediate) 1111 0101 x101 xxxx xxxx xxxx xxxx xxxx */
130 DECODE_SIMULATE (0xfe300000, 0xf4100000, PROBES_PRELOAD_IMM),
131
132 /* memory hint 1111 0110 x001 xxxx xxxx xxxx xxx0 xxxx */
133 /* PLDI (register) 1111 0110 x101 xxxx xxxx xxxx xxx0 xxxx */
134 /* PLDW (register) 1111 0111 x001 xxxx xxxx xxxx xxx0 xxxx */
135 /* PLD (register) 1111 0111 x101 xxxx xxxx xxxx xxx0 xxxx */
136 DECODE_SIMULATE (0xfe300010, 0xf6100000, PROBES_PRELOAD_REG),
137
138 /* BLX (immediate) 1111 101x xxxx xxxx xxxx xxxx xxxx xxxx */
139 DECODE_SIMULATE (0xfe000000, 0xfa000000, PROBES_BRANCH_IMM),
140
141 /* CPS 1111 0001 0000 xxx0 xxxx xxxx xx0x xxxx */
142 /* SETEND 1111 0001 0000 0001 xxxx xxxx 0000 xxxx */
143 /* SRS 1111 100x x1x0 xxxx xxxx xxxx xxxx xxxx */
144 /* RFE 1111 100x x0x1 xxxx xxxx xxxx xxxx xxxx */
145
146 /* Coprocessor instructions... */
147 /* MCRR2 1111 1100 0100 xxxx xxxx xxxx xxxx xxxx */
148 /* MRRC2 1111 1100 0101 xxxx xxxx xxxx xxxx xxxx */
149 /* LDC2 1111 110x xxx1 xxxx xxxx xxxx xxxx xxxx */
150 /* STC2 1111 110x xxx0 xxxx xxxx xxxx xxxx xxxx */
151 /* CDP2 1111 1110 xxxx xxxx xxxx xxxx xxx0 xxxx */
152 /* MCR2 1111 1110 xxx0 xxxx xxxx xxxx xxx1 xxxx */
153 /* MRC2 1111 1110 xxx1 xxxx xxxx xxxx xxx1 xxxx */
154
155 /* Other unallocated instructions... */
156 DECODE_END
157 };
158
159 static const union decode_item arm_cccc_0001_0xx0____0xxx_table[] = {
160 /* Miscellaneous instructions */
161
162 /* MRS cpsr cccc 0001 0000 xxxx xxxx xxxx 0000 xxxx */
163 DECODE_SIMULATEX(0x0ff000f0, 0x01000000, PROBES_MRS,
164 REGS(0, NOPC, 0, 0, 0)),
165
166 /* BX cccc 0001 0010 xxxx xxxx xxxx 0001 xxxx */
167 DECODE_SIMULATE (0x0ff000f0, 0x01200010, PROBES_BRANCH_REG),
168
169 /* BLX (register) cccc 0001 0010 xxxx xxxx xxxx 0011 xxxx */
170 DECODE_SIMULATEX(0x0ff000f0, 0x01200030, PROBES_BRANCH_REG,
171 REGS(0, 0, 0, 0, NOPC)),
172
173 /* CLZ cccc 0001 0110 xxxx xxxx xxxx 0001 xxxx */
174 DECODE_EMULATEX (0x0ff000f0, 0x01600010, PROBES_CLZ,
175 REGS(0, NOPC, 0, 0, NOPC)),
176
177 /* QADD cccc 0001 0000 xxxx xxxx xxxx 0101 xxxx */
178 /* QSUB cccc 0001 0010 xxxx xxxx xxxx 0101 xxxx */
179 /* QDADD cccc 0001 0100 xxxx xxxx xxxx 0101 xxxx */
180 /* QDSUB cccc 0001 0110 xxxx xxxx xxxx 0101 xxxx */
181 DECODE_EMULATEX (0x0f9000f0, 0x01000050, PROBES_SATURATING_ARITHMETIC,
182 REGS(NOPC, NOPC, 0, 0, NOPC)),
183
184 /* BXJ cccc 0001 0010 xxxx xxxx xxxx 0010 xxxx */
185 /* MSR cccc 0001 0x10 xxxx xxxx xxxx 0000 xxxx */
186 /* MRS spsr cccc 0001 0100 xxxx xxxx xxxx 0000 xxxx */
187 /* BKPT 1110 0001 0010 xxxx xxxx xxxx 0111 xxxx */
188 /* SMC cccc 0001 0110 xxxx xxxx xxxx 0111 xxxx */
189 /* And unallocated instructions... */
190 DECODE_END
191 };
192
193 static const union decode_item arm_cccc_0001_0xx0____1xx0_table[] = {
194 /* Halfword multiply and multiply-accumulate */
195
196 /* SMLALxy cccc 0001 0100 xxxx xxxx xxxx 1xx0 xxxx */
197 DECODE_EMULATEX (0x0ff00090, 0x01400080, PROBES_MUL1,
198 REGS(NOPC, NOPC, NOPC, 0, NOPC)),
199
200 /* SMULWy cccc 0001 0010 xxxx xxxx xxxx 1x10 xxxx */
201 DECODE_OR (0x0ff000b0, 0x012000a0),
202 /* SMULxy cccc 0001 0110 xxxx xxxx xxxx 1xx0 xxxx */
203 DECODE_EMULATEX (0x0ff00090, 0x01600080, PROBES_MUL2,
204 REGS(NOPC, 0, NOPC, 0, NOPC)),
205
206 /* SMLAxy cccc 0001 0000 xxxx xxxx xxxx 1xx0 xxxx */
207 DECODE_OR (0x0ff00090, 0x01000080),
208 /* SMLAWy cccc 0001 0010 xxxx xxxx xxxx 1x00 xxxx */
209 DECODE_EMULATEX (0x0ff000b0, 0x01200080, PROBES_MUL2,
210 REGS(NOPC, NOPC, NOPC, 0, NOPC)),
211
212 DECODE_END
213 };
214
215 static const union decode_item arm_cccc_0000_____1001_table[] = {
216 /* Multiply and multiply-accumulate */
217
218 /* MUL cccc 0000 0000 xxxx xxxx xxxx 1001 xxxx */
219 /* MULS cccc 0000 0001 xxxx xxxx xxxx 1001 xxxx */
220 DECODE_EMULATEX (0x0fe000f0, 0x00000090, PROBES_MUL2,
221 REGS(NOPC, 0, NOPC, 0, NOPC)),
222
223 /* MLA cccc 0000 0010 xxxx xxxx xxxx 1001 xxxx */
224 /* MLAS cccc 0000 0011 xxxx xxxx xxxx 1001 xxxx */
225 DECODE_OR (0x0fe000f0, 0x00200090),
226 /* MLS cccc 0000 0110 xxxx xxxx xxxx 1001 xxxx */
227 DECODE_EMULATEX (0x0ff000f0, 0x00600090, PROBES_MUL2,
228 REGS(NOPC, NOPC, NOPC, 0, NOPC)),
229
230 /* UMAAL cccc 0000 0100 xxxx xxxx xxxx 1001 xxxx */
231 DECODE_OR (0x0ff000f0, 0x00400090),
232 /* UMULL cccc 0000 1000 xxxx xxxx xxxx 1001 xxxx */
233 /* UMULLS cccc 0000 1001 xxxx xxxx xxxx 1001 xxxx */
234 /* UMLAL cccc 0000 1010 xxxx xxxx xxxx 1001 xxxx */
235 /* UMLALS cccc 0000 1011 xxxx xxxx xxxx 1001 xxxx */
236 /* SMULL cccc 0000 1100 xxxx xxxx xxxx 1001 xxxx */
237 /* SMULLS cccc 0000 1101 xxxx xxxx xxxx 1001 xxxx */
238 /* SMLAL cccc 0000 1110 xxxx xxxx xxxx 1001 xxxx */
239 /* SMLALS cccc 0000 1111 xxxx xxxx xxxx 1001 xxxx */
240 DECODE_EMULATEX (0x0f8000f0, 0x00800090, PROBES_MUL1,
241 REGS(NOPC, NOPC, NOPC, 0, NOPC)),
242
243 DECODE_END
244 };
245
246 static const union decode_item arm_cccc_0001_____1001_table[] = {
247 /* Synchronization primitives */
248
249 #if __LINUX_ARM_ARCH__ < 6
250 /* Deprecated on ARMv6 and may be UNDEFINED on v7 */
251 /* SMP/SWPB cccc 0001 0x00 xxxx xxxx xxxx 1001 xxxx */
252 DECODE_EMULATEX (0x0fb000f0, 0x01000090, PROBES_SWP,
253 REGS(NOPC, NOPC, 0, 0, NOPC)),
254 #endif
255 /* LDREX/STREX{,D,B,H} cccc 0001 1xxx xxxx xxxx xxxx 1001 xxxx */
256 /* And unallocated instructions... */
257 DECODE_END
258 };
259
260 static const union decode_item arm_cccc_000x_____1xx1_table[] = {
261 /* Extra load/store instructions */
262
263 /* STRHT cccc 0000 xx10 xxxx xxxx xxxx 1011 xxxx */
264 /* ??? cccc 0000 xx10 xxxx xxxx xxxx 11x1 xxxx */
265 /* LDRHT cccc 0000 xx11 xxxx xxxx xxxx 1011 xxxx */
266 /* LDRSBT cccc 0000 xx11 xxxx xxxx xxxx 1101 xxxx */
267 /* LDRSHT cccc 0000 xx11 xxxx xxxx xxxx 1111 xxxx */
268 DECODE_REJECT (0x0f200090, 0x00200090),
269
270 /* LDRD/STRD lr,pc,{... cccc 000x x0x0 xxxx 111x xxxx 1101 xxxx */
271 DECODE_REJECT (0x0e10e0d0, 0x0000e0d0),
272
273 /* LDRD (register) cccc 000x x0x0 xxxx xxxx xxxx 1101 xxxx */
274 /* STRD (register) cccc 000x x0x0 xxxx xxxx xxxx 1111 xxxx */
275 DECODE_EMULATEX (0x0e5000d0, 0x000000d0, PROBES_LDRSTRD,
276 REGS(NOPCWB, NOPCX, 0, 0, NOPC)),
277
278 /* LDRD (immediate) cccc 000x x1x0 xxxx xxxx xxxx 1101 xxxx */
279 /* STRD (immediate) cccc 000x x1x0 xxxx xxxx xxxx 1111 xxxx */
280 DECODE_EMULATEX (0x0e5000d0, 0x004000d0, PROBES_LDRSTRD,
281 REGS(NOPCWB, NOPCX, 0, 0, 0)),
282
283 /* STRH (register) cccc 000x x0x0 xxxx xxxx xxxx 1011 xxxx */
284 DECODE_EMULATEX (0x0e5000f0, 0x000000b0, PROBES_STORE_EXTRA,
285 REGS(NOPCWB, NOPC, 0, 0, NOPC)),
286
287 /* LDRH (register) cccc 000x x0x1 xxxx xxxx xxxx 1011 xxxx */
288 /* LDRSB (register) cccc 000x x0x1 xxxx xxxx xxxx 1101 xxxx */
289 /* LDRSH (register) cccc 000x x0x1 xxxx xxxx xxxx 1111 xxxx */
290 DECODE_EMULATEX (0x0e500090, 0x00100090, PROBES_LOAD_EXTRA,
291 REGS(NOPCWB, NOPC, 0, 0, NOPC)),
292
293 /* STRH (immediate) cccc 000x x1x0 xxxx xxxx xxxx 1011 xxxx */
294 DECODE_EMULATEX (0x0e5000f0, 0x004000b0, PROBES_STORE_EXTRA,
295 REGS(NOPCWB, NOPC, 0, 0, 0)),
296
297 /* LDRH (immediate) cccc 000x x1x1 xxxx xxxx xxxx 1011 xxxx */
298 /* LDRSB (immediate) cccc 000x x1x1 xxxx xxxx xxxx 1101 xxxx */
299 /* LDRSH (immediate) cccc 000x x1x1 xxxx xxxx xxxx 1111 xxxx */
300 DECODE_EMULATEX (0x0e500090, 0x00500090, PROBES_LOAD_EXTRA,
301 REGS(NOPCWB, NOPC, 0, 0, 0)),
302
303 DECODE_END
304 };
305
306 static const union decode_item arm_cccc_000x_table[] = {
307 /* Data-processing (register) */
308
309 /* <op>S PC, ... cccc 000x xxx1 xxxx 1111 xxxx xxxx xxxx */
310 DECODE_REJECT (0x0e10f000, 0x0010f000),
311
312 /* MOV IP, SP 1110 0001 1010 0000 1100 0000 0000 1101 */
313 DECODE_SIMULATE (0xffffffff, 0xe1a0c00d, PROBES_MOV_IP_SP),
314
315 /* TST (register) cccc 0001 0001 xxxx xxxx xxxx xxx0 xxxx */
316 /* TEQ (register) cccc 0001 0011 xxxx xxxx xxxx xxx0 xxxx */
317 /* CMP (register) cccc 0001 0101 xxxx xxxx xxxx xxx0 xxxx */
318 /* CMN (register) cccc 0001 0111 xxxx xxxx xxxx xxx0 xxxx */
319 DECODE_EMULATEX (0x0f900010, 0x01100000, PROBES_DATA_PROCESSING_REG,
320 REGS(ANY, 0, 0, 0, ANY)),
321
322 /* MOV (register) cccc 0001 101x xxxx xxxx xxxx xxx0 xxxx */
323 /* MVN (register) cccc 0001 111x xxxx xxxx xxxx xxx0 xxxx */
324 DECODE_EMULATEX (0x0fa00010, 0x01a00000, PROBES_DATA_PROCESSING_REG,
325 REGS(0, ANY, 0, 0, ANY)),
326
327 /* AND (register) cccc 0000 000x xxxx xxxx xxxx xxx0 xxxx */
328 /* EOR (register) cccc 0000 001x xxxx xxxx xxxx xxx0 xxxx */
329 /* SUB (register) cccc 0000 010x xxxx xxxx xxxx xxx0 xxxx */
330 /* RSB (register) cccc 0000 011x xxxx xxxx xxxx xxx0 xxxx */
331 /* ADD (register) cccc 0000 100x xxxx xxxx xxxx xxx0 xxxx */
332 /* ADC (register) cccc 0000 101x xxxx xxxx xxxx xxx0 xxxx */
333 /* SBC (register) cccc 0000 110x xxxx xxxx xxxx xxx0 xxxx */
334 /* RSC (register) cccc 0000 111x xxxx xxxx xxxx xxx0 xxxx */
335 /* ORR (register) cccc 0001 100x xxxx xxxx xxxx xxx0 xxxx */
336 /* BIC (register) cccc 0001 110x xxxx xxxx xxxx xxx0 xxxx */
337 DECODE_EMULATEX (0x0e000010, 0x00000000, PROBES_DATA_PROCESSING_REG,
338 REGS(ANY, ANY, 0, 0, ANY)),
339
340 /* TST (reg-shift reg) cccc 0001 0001 xxxx xxxx xxxx 0xx1 xxxx */
341 /* TEQ (reg-shift reg) cccc 0001 0011 xxxx xxxx xxxx 0xx1 xxxx */
342 /* CMP (reg-shift reg) cccc 0001 0101 xxxx xxxx xxxx 0xx1 xxxx */
343 /* CMN (reg-shift reg) cccc 0001 0111 xxxx xxxx xxxx 0xx1 xxxx */
344 DECODE_EMULATEX (0x0f900090, 0x01100010, PROBES_DATA_PROCESSING_REG,
345 REGS(NOPC, 0, NOPC, 0, NOPC)),
346
347 /* MOV (reg-shift reg) cccc 0001 101x xxxx xxxx xxxx 0xx1 xxxx */
348 /* MVN (reg-shift reg) cccc 0001 111x xxxx xxxx xxxx 0xx1 xxxx */
349 DECODE_EMULATEX (0x0fa00090, 0x01a00010, PROBES_DATA_PROCESSING_REG,
350 REGS(0, NOPC, NOPC, 0, NOPC)),
351
352 /* AND (reg-shift reg) cccc 0000 000x xxxx xxxx xxxx 0xx1 xxxx */
353 /* EOR (reg-shift reg) cccc 0000 001x xxxx xxxx xxxx 0xx1 xxxx */
354 /* SUB (reg-shift reg) cccc 0000 010x xxxx xxxx xxxx 0xx1 xxxx */
355 /* RSB (reg-shift reg) cccc 0000 011x xxxx xxxx xxxx 0xx1 xxxx */
356 /* ADD (reg-shift reg) cccc 0000 100x xxxx xxxx xxxx 0xx1 xxxx */
357 /* ADC (reg-shift reg) cccc 0000 101x xxxx xxxx xxxx 0xx1 xxxx */
358 /* SBC (reg-shift reg) cccc 0000 110x xxxx xxxx xxxx 0xx1 xxxx */
359 /* RSC (reg-shift reg) cccc 0000 111x xxxx xxxx xxxx 0xx1 xxxx */
360 /* ORR (reg-shift reg) cccc 0001 100x xxxx xxxx xxxx 0xx1 xxxx */
361 /* BIC (reg-shift reg) cccc 0001 110x xxxx xxxx xxxx 0xx1 xxxx */
362 DECODE_EMULATEX (0x0e000090, 0x00000010, PROBES_DATA_PROCESSING_REG,
363 REGS(NOPC, NOPC, NOPC, 0, NOPC)),
364
365 DECODE_END
366 };
367
368 static const union decode_item arm_cccc_001x_table[] = {
369 /* Data-processing (immediate) */
370
371 /* MOVW cccc 0011 0000 xxxx xxxx xxxx xxxx xxxx */
372 /* MOVT cccc 0011 0100 xxxx xxxx xxxx xxxx xxxx */
373 DECODE_EMULATEX (0x0fb00000, 0x03000000, PROBES_MOV_HALFWORD,
374 REGS(0, NOPC, 0, 0, 0)),
375
376 /* YIELD cccc 0011 0010 0000 xxxx xxxx 0000 0001 */
377 DECODE_OR (0x0fff00ff, 0x03200001),
378 /* SEV cccc 0011 0010 0000 xxxx xxxx 0000 0100 */
379 DECODE_EMULATE (0x0fff00ff, 0x03200004, PROBES_SEV),
380 /* NOP cccc 0011 0010 0000 xxxx xxxx 0000 0000 */
381 /* WFE cccc 0011 0010 0000 xxxx xxxx 0000 0010 */
382 /* WFI cccc 0011 0010 0000 xxxx xxxx 0000 0011 */
383 DECODE_SIMULATE (0x0fff00fc, 0x03200000, PROBES_WFE),
384 /* DBG cccc 0011 0010 0000 xxxx xxxx ffff xxxx */
385 /* unallocated hints cccc 0011 0010 0000 xxxx xxxx xxxx xxxx */
386 /* MSR (immediate) cccc 0011 0x10 xxxx xxxx xxxx xxxx xxxx */
387 DECODE_REJECT (0x0fb00000, 0x03200000),
388
389 /* <op>S PC, ... cccc 001x xxx1 xxxx 1111 xxxx xxxx xxxx */
390 DECODE_REJECT (0x0e10f000, 0x0210f000),
391
392 /* TST (immediate) cccc 0011 0001 xxxx xxxx xxxx xxxx xxxx */
393 /* TEQ (immediate) cccc 0011 0011 xxxx xxxx xxxx xxxx xxxx */
394 /* CMP (immediate) cccc 0011 0101 xxxx xxxx xxxx xxxx xxxx */
395 /* CMN (immediate) cccc 0011 0111 xxxx xxxx xxxx xxxx xxxx */
396 DECODE_EMULATEX (0x0f900000, 0x03100000, PROBES_DATA_PROCESSING_IMM,
397 REGS(ANY, 0, 0, 0, 0)),
398
399 /* MOV (immediate) cccc 0011 101x xxxx xxxx xxxx xxxx xxxx */
400 /* MVN (immediate) cccc 0011 111x xxxx xxxx xxxx xxxx xxxx */
401 DECODE_EMULATEX (0x0fa00000, 0x03a00000, PROBES_DATA_PROCESSING_IMM,
402 REGS(0, ANY, 0, 0, 0)),
403
404 /* AND (immediate) cccc 0010 000x xxxx xxxx xxxx xxxx xxxx */
405 /* EOR (immediate) cccc 0010 001x xxxx xxxx xxxx xxxx xxxx */
406 /* SUB (immediate) cccc 0010 010x xxxx xxxx xxxx xxxx xxxx */
407 /* RSB (immediate) cccc 0010 011x xxxx xxxx xxxx xxxx xxxx */
408 /* ADD (immediate) cccc 0010 100x xxxx xxxx xxxx xxxx xxxx */
409 /* ADC (immediate) cccc 0010 101x xxxx xxxx xxxx xxxx xxxx */
410 /* SBC (immediate) cccc 0010 110x xxxx xxxx xxxx xxxx xxxx */
411 /* RSC (immediate) cccc 0010 111x xxxx xxxx xxxx xxxx xxxx */
412 /* ORR (immediate) cccc 0011 100x xxxx xxxx xxxx xxxx xxxx */
413 /* BIC (immediate) cccc 0011 110x xxxx xxxx xxxx xxxx xxxx */
414 DECODE_EMULATEX (0x0e000000, 0x02000000, PROBES_DATA_PROCESSING_IMM,
415 REGS(ANY, ANY, 0, 0, 0)),
416
417 DECODE_END
418 };
419
420 static const union decode_item arm_cccc_0110_____xxx1_table[] = {
421 /* Media instructions */
422
423 /* SEL cccc 0110 1000 xxxx xxxx xxxx 1011 xxxx */
424 DECODE_EMULATEX (0x0ff000f0, 0x068000b0, PROBES_SATURATE,
425 REGS(NOPC, NOPC, 0, 0, NOPC)),
426
427 /* SSAT cccc 0110 101x xxxx xxxx xxxx xx01 xxxx */
428 /* USAT cccc 0110 111x xxxx xxxx xxxx xx01 xxxx */
429 DECODE_OR(0x0fa00030, 0x06a00010),
430 /* SSAT16 cccc 0110 1010 xxxx xxxx xxxx 0011 xxxx */
431 /* USAT16 cccc 0110 1110 xxxx xxxx xxxx 0011 xxxx */
432 DECODE_EMULATEX (0x0fb000f0, 0x06a00030, PROBES_SATURATE,
433 REGS(0, NOPC, 0, 0, NOPC)),
434
435 /* REV cccc 0110 1011 xxxx xxxx xxxx 0011 xxxx */
436 /* REV16 cccc 0110 1011 xxxx xxxx xxxx 1011 xxxx */
437 /* RBIT cccc 0110 1111 xxxx xxxx xxxx 0011 xxxx */
438 /* REVSH cccc 0110 1111 xxxx xxxx xxxx 1011 xxxx */
439 DECODE_EMULATEX (0x0fb00070, 0x06b00030, PROBES_REV,
440 REGS(0, NOPC, 0, 0, NOPC)),
441
442 /* ??? cccc 0110 0x00 xxxx xxxx xxxx xxx1 xxxx */
443 DECODE_REJECT (0x0fb00010, 0x06000010),
444 /* ??? cccc 0110 0xxx xxxx xxxx xxxx 1011 xxxx */
445 DECODE_REJECT (0x0f8000f0, 0x060000b0),
446 /* ??? cccc 0110 0xxx xxxx xxxx xxxx 1101 xxxx */
447 DECODE_REJECT (0x0f8000f0, 0x060000d0),
448 /* SADD16 cccc 0110 0001 xxxx xxxx xxxx 0001 xxxx */
449 /* SADDSUBX cccc 0110 0001 xxxx xxxx xxxx 0011 xxxx */
450 /* SSUBADDX cccc 0110 0001 xxxx xxxx xxxx 0101 xxxx */
451 /* SSUB16 cccc 0110 0001 xxxx xxxx xxxx 0111 xxxx */
452 /* SADD8 cccc 0110 0001 xxxx xxxx xxxx 1001 xxxx */
453 /* SSUB8 cccc 0110 0001 xxxx xxxx xxxx 1111 xxxx */
454 /* QADD16 cccc 0110 0010 xxxx xxxx xxxx 0001 xxxx */
455 /* QADDSUBX cccc 0110 0010 xxxx xxxx xxxx 0011 xxxx */
456 /* QSUBADDX cccc 0110 0010 xxxx xxxx xxxx 0101 xxxx */
457 /* QSUB16 cccc 0110 0010 xxxx xxxx xxxx 0111 xxxx */
458 /* QADD8 cccc 0110 0010 xxxx xxxx xxxx 1001 xxxx */
459 /* QSUB8 cccc 0110 0010 xxxx xxxx xxxx 1111 xxxx */
460 /* SHADD16 cccc 0110 0011 xxxx xxxx xxxx 0001 xxxx */
461 /* SHADDSUBX cccc 0110 0011 xxxx xxxx xxxx 0011 xxxx */
462 /* SHSUBADDX cccc 0110 0011 xxxx xxxx xxxx 0101 xxxx */
463 /* SHSUB16 cccc 0110 0011 xxxx xxxx xxxx 0111 xxxx */
464 /* SHADD8 cccc 0110 0011 xxxx xxxx xxxx 1001 xxxx */
465 /* SHSUB8 cccc 0110 0011 xxxx xxxx xxxx 1111 xxxx */
466 /* UADD16 cccc 0110 0101 xxxx xxxx xxxx 0001 xxxx */
467 /* UADDSUBX cccc 0110 0101 xxxx xxxx xxxx 0011 xxxx */
468 /* USUBADDX cccc 0110 0101 xxxx xxxx xxxx 0101 xxxx */
469 /* USUB16 cccc 0110 0101 xxxx xxxx xxxx 0111 xxxx */
470 /* UADD8 cccc 0110 0101 xxxx xxxx xxxx 1001 xxxx */
471 /* USUB8 cccc 0110 0101 xxxx xxxx xxxx 1111 xxxx */
472 /* UQADD16 cccc 0110 0110 xxxx xxxx xxxx 0001 xxxx */
473 /* UQADDSUBX cccc 0110 0110 xxxx xxxx xxxx 0011 xxxx */
474 /* UQSUBADDX cccc 0110 0110 xxxx xxxx xxxx 0101 xxxx */
475 /* UQSUB16 cccc 0110 0110 xxxx xxxx xxxx 0111 xxxx */
476 /* UQADD8 cccc 0110 0110 xxxx xxxx xxxx 1001 xxxx */
477 /* UQSUB8 cccc 0110 0110 xxxx xxxx xxxx 1111 xxxx */
478 /* UHADD16 cccc 0110 0111 xxxx xxxx xxxx 0001 xxxx */
479 /* UHADDSUBX cccc 0110 0111 xxxx xxxx xxxx 0011 xxxx */
480 /* UHSUBADDX cccc 0110 0111 xxxx xxxx xxxx 0101 xxxx */
481 /* UHSUB16 cccc 0110 0111 xxxx xxxx xxxx 0111 xxxx */
482 /* UHADD8 cccc 0110 0111 xxxx xxxx xxxx 1001 xxxx */
483 /* UHSUB8 cccc 0110 0111 xxxx xxxx xxxx 1111 xxxx */
484 DECODE_EMULATEX (0x0f800010, 0x06000010, PROBES_MMI,
485 REGS(NOPC, NOPC, 0, 0, NOPC)),
486
487 /* PKHBT cccc 0110 1000 xxxx xxxx xxxx x001 xxxx */
488 /* PKHTB cccc 0110 1000 xxxx xxxx xxxx x101 xxxx */
489 DECODE_EMULATEX (0x0ff00030, 0x06800010, PROBES_PACK,
490 REGS(NOPC, NOPC, 0, 0, NOPC)),
491
492 /* ??? cccc 0110 1001 xxxx xxxx xxxx 0111 xxxx */
493 /* ??? cccc 0110 1101 xxxx xxxx xxxx 0111 xxxx */
494 DECODE_REJECT (0x0fb000f0, 0x06900070),
495
496 /* SXTB16 cccc 0110 1000 1111 xxxx xxxx 0111 xxxx */
497 /* SXTB cccc 0110 1010 1111 xxxx xxxx 0111 xxxx */
498 /* SXTH cccc 0110 1011 1111 xxxx xxxx 0111 xxxx */
499 /* UXTB16 cccc 0110 1100 1111 xxxx xxxx 0111 xxxx */
500 /* UXTB cccc 0110 1110 1111 xxxx xxxx 0111 xxxx */
501 /* UXTH cccc 0110 1111 1111 xxxx xxxx 0111 xxxx */
502 DECODE_EMULATEX (0x0f8f00f0, 0x068f0070, PROBES_EXTEND,
503 REGS(0, NOPC, 0, 0, NOPC)),
504
505 /* SXTAB16 cccc 0110 1000 xxxx xxxx xxxx 0111 xxxx */
506 /* SXTAB cccc 0110 1010 xxxx xxxx xxxx 0111 xxxx */
507 /* SXTAH cccc 0110 1011 xxxx xxxx xxxx 0111 xxxx */
508 /* UXTAB16 cccc 0110 1100 xxxx xxxx xxxx 0111 xxxx */
509 /* UXTAB cccc 0110 1110 xxxx xxxx xxxx 0111 xxxx */
510 /* UXTAH cccc 0110 1111 xxxx xxxx xxxx 0111 xxxx */
511 DECODE_EMULATEX (0x0f8000f0, 0x06800070, PROBES_EXTEND_ADD,
512 REGS(NOPCX, NOPC, 0, 0, NOPC)),
513
514 DECODE_END
515 };
516
517 static const union decode_item arm_cccc_0111_____xxx1_table[] = {
518 /* Media instructions */
519
520 /* UNDEFINED cccc 0111 1111 xxxx xxxx xxxx 1111 xxxx */
521 DECODE_REJECT (0x0ff000f0, 0x07f000f0),
522
523 /* SMLALD cccc 0111 0100 xxxx xxxx xxxx 00x1 xxxx */
524 /* SMLSLD cccc 0111 0100 xxxx xxxx xxxx 01x1 xxxx */
525 DECODE_EMULATEX (0x0ff00090, 0x07400010, PROBES_MUL_ADD_LONG,
526 REGS(NOPC, NOPC, NOPC, 0, NOPC)),
527
528 /* SMUAD cccc 0111 0000 xxxx 1111 xxxx 00x1 xxxx */
529 /* SMUSD cccc 0111 0000 xxxx 1111 xxxx 01x1 xxxx */
530 DECODE_OR (0x0ff0f090, 0x0700f010),
531 /* SMMUL cccc 0111 0101 xxxx 1111 xxxx 00x1 xxxx */
532 DECODE_OR (0x0ff0f0d0, 0x0750f010),
533 /* USAD8 cccc 0111 1000 xxxx 1111 xxxx 0001 xxxx */
534 DECODE_EMULATEX (0x0ff0f0f0, 0x0780f010, PROBES_MUL_ADD,
535 REGS(NOPC, 0, NOPC, 0, NOPC)),
536
537 /* SMLAD cccc 0111 0000 xxxx xxxx xxxx 00x1 xxxx */
538 /* SMLSD cccc 0111 0000 xxxx xxxx xxxx 01x1 xxxx */
539 DECODE_OR (0x0ff00090, 0x07000010),
540 /* SMMLA cccc 0111 0101 xxxx xxxx xxxx 00x1 xxxx */
541 DECODE_OR (0x0ff000d0, 0x07500010),
542 /* USADA8 cccc 0111 1000 xxxx xxxx xxxx 0001 xxxx */
543 DECODE_EMULATEX (0x0ff000f0, 0x07800010, PROBES_MUL_ADD,
544 REGS(NOPC, NOPCX, NOPC, 0, NOPC)),
545
546 /* SMMLS cccc 0111 0101 xxxx xxxx xxxx 11x1 xxxx */
547 DECODE_EMULATEX (0x0ff000d0, 0x075000d0, PROBES_MUL_ADD,
548 REGS(NOPC, NOPC, NOPC, 0, NOPC)),
549
550 /* SBFX cccc 0111 101x xxxx xxxx xxxx x101 xxxx */
551 /* UBFX cccc 0111 111x xxxx xxxx xxxx x101 xxxx */
552 DECODE_EMULATEX (0x0fa00070, 0x07a00050, PROBES_BITFIELD,
553 REGS(0, NOPC, 0, 0, NOPC)),
554
555 /* BFC cccc 0111 110x xxxx xxxx xxxx x001 1111 */
556 DECODE_EMULATEX (0x0fe0007f, 0x07c0001f, PROBES_BITFIELD,
557 REGS(0, NOPC, 0, 0, 0)),
558
559 /* BFI cccc 0111 110x xxxx xxxx xxxx x001 xxxx */
560 DECODE_EMULATEX (0x0fe00070, 0x07c00010, PROBES_BITFIELD,
561 REGS(0, NOPC, 0, 0, NOPCX)),
562
563 DECODE_END
564 };
565
566 static const union decode_item arm_cccc_01xx_table[] = {
567 /* Load/store word and unsigned byte */
568
569 /* LDRB/STRB pc,[...] cccc 01xx x0xx xxxx xxxx xxxx xxxx xxxx */
570 DECODE_REJECT (0x0c40f000, 0x0440f000),
571
572 /* STRT cccc 01x0 x010 xxxx xxxx xxxx xxxx xxxx */
573 /* LDRT cccc 01x0 x011 xxxx xxxx xxxx xxxx xxxx */
574 /* STRBT cccc 01x0 x110 xxxx xxxx xxxx xxxx xxxx */
575 /* LDRBT cccc 01x0 x111 xxxx xxxx xxxx xxxx xxxx */
576 DECODE_REJECT (0x0d200000, 0x04200000),
577
578 /* STR (immediate) cccc 010x x0x0 xxxx xxxx xxxx xxxx xxxx */
579 /* STRB (immediate) cccc 010x x1x0 xxxx xxxx xxxx xxxx xxxx */
580 DECODE_EMULATEX (0x0e100000, 0x04000000, PROBES_STORE,
581 REGS(NOPCWB, ANY, 0, 0, 0)),
582
583 /* LDR (immediate) cccc 010x x0x1 xxxx xxxx xxxx xxxx xxxx */
584 /* LDRB (immediate) cccc 010x x1x1 xxxx xxxx xxxx xxxx xxxx */
585 DECODE_EMULATEX (0x0e100000, 0x04100000, PROBES_LOAD,
586 REGS(NOPCWB, ANY, 0, 0, 0)),
587
588 /* STR (register) cccc 011x x0x0 xxxx xxxx xxxx xxxx xxxx */
589 /* STRB (register) cccc 011x x1x0 xxxx xxxx xxxx xxxx xxxx */
590 DECODE_EMULATEX (0x0e100000, 0x06000000, PROBES_STORE,
591 REGS(NOPCWB, ANY, 0, 0, NOPC)),
592
593 /* LDR (register) cccc 011x x0x1 xxxx xxxx xxxx xxxx xxxx */
594 /* LDRB (register) cccc 011x x1x1 xxxx xxxx xxxx xxxx xxxx */
595 DECODE_EMULATEX (0x0e100000, 0x06100000, PROBES_LOAD,
596 REGS(NOPCWB, ANY, 0, 0, NOPC)),
597
598 DECODE_END
599 };
600
601 static const union decode_item arm_cccc_100x_table[] = {
602 /* Block data transfer instructions */
603
604 /* LDM cccc 100x x0x1 xxxx xxxx xxxx xxxx xxxx */
605 /* STM cccc 100x x0x0 xxxx xxxx xxxx xxxx xxxx */
606 DECODE_CUSTOM (0x0e400000, 0x08000000, PROBES_LDMSTM),
607
608 /* STM (user registers) cccc 100x x1x0 xxxx xxxx xxxx xxxx xxxx */
609 /* LDM (user registers) cccc 100x x1x1 xxxx 0xxx xxxx xxxx xxxx */
610 /* LDM (exception ret) cccc 100x x1x1 xxxx 1xxx xxxx xxxx xxxx */
611 DECODE_END
612 };
613
614 const union decode_item probes_decode_arm_table[] = {
615 /*
616 * Unconditional instructions
617 * 1111 xxxx xxxx xxxx xxxx xxxx xxxx xxxx
618 */
619 DECODE_TABLE (0xf0000000, 0xf0000000, arm_1111_table),
620
621 /*
622 * Miscellaneous instructions
623 * cccc 0001 0xx0 xxxx xxxx xxxx 0xxx xxxx
624 */
625 DECODE_TABLE (0x0f900080, 0x01000000, arm_cccc_0001_0xx0____0xxx_table),
626
627 /*
628 * Halfword multiply and multiply-accumulate
629 * cccc 0001 0xx0 xxxx xxxx xxxx 1xx0 xxxx
630 */
631 DECODE_TABLE (0x0f900090, 0x01000080, arm_cccc_0001_0xx0____1xx0_table),
632
633 /*
634 * Multiply and multiply-accumulate
635 * cccc 0000 xxxx xxxx xxxx xxxx 1001 xxxx
636 */
637 DECODE_TABLE (0x0f0000f0, 0x00000090, arm_cccc_0000_____1001_table),
638
639 /*
640 * Synchronization primitives
641 * cccc 0001 xxxx xxxx xxxx xxxx 1001 xxxx
642 */
643 DECODE_TABLE (0x0f0000f0, 0x01000090, arm_cccc_0001_____1001_table),
644
645 /*
646 * Extra load/store instructions
647 * cccc 000x xxxx xxxx xxxx xxxx 1xx1 xxxx
648 */
649 DECODE_TABLE (0x0e000090, 0x00000090, arm_cccc_000x_____1xx1_table),
650
651 /*
652 * Data-processing (register)
653 * cccc 000x xxxx xxxx xxxx xxxx xxx0 xxxx
654 * Data-processing (register-shifted register)
655 * cccc 000x xxxx xxxx xxxx xxxx 0xx1 xxxx
656 */
657 DECODE_TABLE (0x0e000000, 0x00000000, arm_cccc_000x_table),
658
659 /*
660 * Data-processing (immediate)
661 * cccc 001x xxxx xxxx xxxx xxxx xxxx xxxx
662 */
663 DECODE_TABLE (0x0e000000, 0x02000000, arm_cccc_001x_table),
664
665 /*
666 * Media instructions
667 * cccc 011x xxxx xxxx xxxx xxxx xxx1 xxxx
668 */
669 DECODE_TABLE (0x0f000010, 0x06000010, arm_cccc_0110_____xxx1_table),
670 DECODE_TABLE (0x0f000010, 0x07000010, arm_cccc_0111_____xxx1_table),
671
672 /*
673 * Load/store word and unsigned byte
674 * cccc 01xx xxxx xxxx xxxx xxxx xxxx xxxx
675 */
676 DECODE_TABLE (0x0c000000, 0x04000000, arm_cccc_01xx_table),
677
678 /*
679 * Block data transfer instructions
680 * cccc 100x xxxx xxxx xxxx xxxx xxxx xxxx
681 */
682 DECODE_TABLE (0x0e000000, 0x08000000, arm_cccc_100x_table),
683
684 /* B cccc 1010 xxxx xxxx xxxx xxxx xxxx xxxx */
685 /* BL cccc 1011 xxxx xxxx xxxx xxxx xxxx xxxx */
686 DECODE_SIMULATE (0x0e000000, 0x0a000000, PROBES_BRANCH),
687
688 /*
689 * Supervisor Call, and coprocessor instructions
690 */
691
692 /* MCRR cccc 1100 0100 xxxx xxxx xxxx xxxx xxxx */
693 /* MRRC cccc 1100 0101 xxxx xxxx xxxx xxxx xxxx */
694 /* LDC cccc 110x xxx1 xxxx xxxx xxxx xxxx xxxx */
695 /* STC cccc 110x xxx0 xxxx xxxx xxxx xxxx xxxx */
696 /* CDP cccc 1110 xxxx xxxx xxxx xxxx xxx0 xxxx */
697 /* MCR cccc 1110 xxx0 xxxx xxxx xxxx xxx1 xxxx */
698 /* MRC cccc 1110 xxx1 xxxx xxxx xxxx xxx1 xxxx */
699 /* SVC cccc 1111 xxxx xxxx xxxx xxxx xxxx xxxx */
700 DECODE_REJECT (0x0c000000, 0x0c000000),
701
702 DECODE_END
703 };
704 #ifdef CONFIG_ARM_KPROBES_TEST_MODULE
705 EXPORT_SYMBOL_GPL(probes_decode_arm_table);
706 #endif
707
arm_singlestep(probes_opcode_t insn,struct arch_probes_insn * asi,struct pt_regs * regs)708 static void __kprobes arm_singlestep(probes_opcode_t insn,
709 struct arch_probes_insn *asi, struct pt_regs *regs)
710 {
711 regs->ARM_pc += 4;
712 asi->insn_handler(insn, asi, regs);
713 }
714
715 /* Return:
716 * INSN_REJECTED If instruction is one not allowed to kprobe,
717 * INSN_GOOD If instruction is supported and uses instruction slot,
718 * INSN_GOOD_NO_SLOT If instruction is supported but doesn't use its slot.
719 *
720 * For instructions we don't want to kprobe (INSN_REJECTED return result):
721 * These are generally ones that modify the processor state making
722 * them "hard" to simulate such as switches processor modes or
723 * make accesses in alternate modes. Any of these could be simulated
724 * if the work was put into it, but low return considering they
725 * should also be very rare.
726 */
727 enum probes_insn __kprobes
arm_probes_decode_insn(probes_opcode_t insn,struct arch_probes_insn * asi,bool emulate,const union decode_action * actions,const struct decode_checker * checkers[])728 arm_probes_decode_insn(probes_opcode_t insn, struct arch_probes_insn *asi,
729 bool emulate, const union decode_action *actions,
730 const struct decode_checker *checkers[])
731 {
732 asi->insn_singlestep = arm_singlestep;
733 asi->insn_check_cc = probes_condition_checks[insn>>28];
734 return probes_decode_insn(insn, asi, probes_decode_arm_table, false,
735 emulate, actions, checkers);
736 }
737
