git.sur5r.net Git - openocd/blob - src/target/arm_dpm.c

   1 /*
   2  * Copyright (C) 2009 by David Brownell
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #ifdef HAVE_CONFIG_H
  19 #include "config.h"
  20 #endif
  21
  22 #include "arm.h"
  23 #include "arm_dpm.h"
  24 #include "armv8_dpm.h"
  25 #include <jtag/jtag.h>
  26 #include "register.h"
  27 #include "breakpoints.h"
  28 #include "target_type.h"
  29 #include "arm_opcodes.h"
  30
  31
  32 /**
  33  * @file
  34  * Implements various ARM DPM operations using architectural debug registers.
  35  * These routines layer over core-specific communication methods to cope with
  36  * implementation differences between cores like ARM1136 and Cortex-A8.
  37  *
  38  * The "Debug Programmers' Model" (DPM) for ARMv6 and ARMv7 is defined by
  39  * Part C (Debug Architecture) of the ARM Architecture Reference Manual,
  40  * ARMv7-A and ARMv7-R edition (ARM DDI 0406B).  In OpenOCD, DPM operations
  41  * are abstracted through internal programming interfaces to share code and
  42  * to minimize needless differences in debug behavior between cores.
  43  */
  44
  45 /*----------------------------------------------------------------------*/
  46
  47 /*
  48  * Coprocessor support
  49  */
  50
  51 /* Read coprocessor */
  52 static int dpm_mrc(struct target *target, int cpnum,
  53         uint32_t op1, uint32_t op2, uint32_t CRn, uint32_t CRm,
  54         uint32_t *value)
  55 {
  56         struct arm *arm = target_to_arm(target);
  57         struct arm_dpm *dpm = arm->dpm;
  58         int retval;
  59
  60         retval = dpm->prepare(dpm);
  61         if (retval != ERROR_OK)
  62                 return retval;
  63
  64         LOG_DEBUG("MRC p%d, %d, r0, c%d, c%d, %d", cpnum,
  65                 (int) op1, (int) CRn,
  66                 (int) CRm, (int) op2);
  67
  68         /* read coprocessor register into R0; return via DCC */
  69         retval = dpm->instr_read_data_r0(dpm,
  70                         ARMV4_5_MRC(cpnum, op1, 0, CRn, CRm, op2),
  71                         value);
  72
  73         /* (void) */ dpm->finish(dpm);
  74         return retval;
  75 }
  76
  77 static int dpm_mcr(struct target *target, int cpnum,
  78         uint32_t op1, uint32_t op2, uint32_t CRn, uint32_t CRm,
  79         uint32_t value)
  80 {
  81         struct arm *arm = target_to_arm(target);
  82         struct arm_dpm *dpm = arm->dpm;
  83         int retval;
  84
  85         retval = dpm->prepare(dpm);
  86         if (retval != ERROR_OK)
  87                 return retval;
  88
  89         LOG_DEBUG("MCR p%d, %d, r0, c%d, c%d, %d", cpnum,
  90                 (int) op1, (int) CRn,
  91                 (int) CRm, (int) op2);
  92
  93         /* read DCC into r0; then write coprocessor register from R0 */
  94         retval = dpm->instr_write_data_r0(dpm,
  95                         ARMV4_5_MCR(cpnum, op1, 0, CRn, CRm, op2),
  96                         value);
  97
  98         /* (void) */ dpm->finish(dpm);
  99         return retval;
 100 }
 101
 102 /*----------------------------------------------------------------------*/
 103
 104 /*
 105  * Register access utilities
 106  */
 107
 108 /* Toggles between recorded core mode (USR, SVC, etc) and a temporary one.
 109  * Routines *must* restore the original mode before returning!!
 110  */
 111 int dpm_modeswitch(struct arm_dpm *dpm, enum arm_mode mode)
 112 {
 113         int retval;
 114         uint32_t cpsr;
 115
 116         /* restore previous mode */
 117         if (mode == ARM_MODE_ANY)
 118                 cpsr = buf_get_u32(dpm->arm->cpsr->value, 0, 32);
 119
 120         /* else force to the specified mode */
 121         else
 122                 cpsr = mode;
 123
 124         retval = dpm->instr_write_data_r0(dpm, ARMV4_5_MSR_GP(0, 0xf, 0), cpsr);
 125         if (retval != ERROR_OK)
 126                 return retval;
 127
 128         if (dpm->instr_cpsr_sync)
 129                 retval = dpm->instr_cpsr_sync(dpm);
 130
 131         return retval;
 132 }
 133
 134 /* Read 64bit VFP registers */
 135 static int dpm_read_reg_u64(struct arm_dpm *dpm, struct reg *r, unsigned regnum)
 136 {
 137         int retval = ERROR_FAIL;
 138         uint32_t value_r0, value_r1;
 139
 140         switch (regnum) {
 141                 case ARM_VFP_V3_D0 ... ARM_VFP_V3_D31:
 142                         /* move from double word register to r0:r1: "vmov r0, r1, vm"
 143                          * then read r0 via dcc
 144                          */
 145                         retval = dpm->instr_read_data_r0(dpm,
 146                                 ARMV4_5_VMOV(1, 1, 0, ((regnum - ARM_VFP_V3_D0) >> 4),
 147                                 ((regnum - ARM_VFP_V3_D0) & 0xf)), &value_r0);
 148                         /* read r1 via dcc */
 149                         retval = dpm->instr_read_data_dcc(dpm,
 150                                 ARMV4_5_MCR(14, 0, 1, 0, 5, 0),
 151                                 &value_r1);
 152                         break;
 153                 default:
 154
 155                         break;
 156         }
 157
 158         if (retval == ERROR_OK) {
 159                 buf_set_u32(r->value, 0, 32, value_r0);
 160                 buf_set_u32(r->value + 4, 0, 32, value_r1);
 161                 r->valid = true;
 162                 r->dirty = false;
 163                 LOG_DEBUG("READ: %s, %8.8x, %8.8x", r->name,
 164                                 (unsigned) value_r0, (unsigned) value_r1);
 165         }
 166
 167         return retval;
 168 }
 169
 170 /* just read the register -- rely on the core mode being right */
 171 static int dpm_read_reg(struct arm_dpm *dpm, struct reg *r, unsigned regnum)
 172 {
 173         uint32_t value;
 174         int retval;
 175
 176         switch (regnum) {
 177                 case 0 ... 14:
 178                         /* return via DCC:  "MCR p14, 0, Rnum, c0, c5, 0" */
 179                         retval = dpm->instr_read_data_dcc(dpm,
 180                                 ARMV4_5_MCR(14, 0, regnum, 0, 5, 0),
 181                                 &value);
 182                         break;
 183                 case 15:/* PC
 184                          * "MOV r0, pc"; then return via DCC */
 185                         retval = dpm->instr_read_data_r0(dpm, 0xe1a0000f, &value);
 186
 187                         /* NOTE: this seems like a slightly awkward place to update
 188                          * this value ... but if the PC gets written (the only way
 189                          * to change what we compute), the arch spec says subsequent
 190                          * reads return values which are "unpredictable".  So this
 191                          * is always right except in those broken-by-intent cases.
 192                          */
 193                         switch (dpm->arm->core_state) {
 194                                 case ARM_STATE_ARM:
 195                                         value -= 8;
 196                                         break;
 197                                 case ARM_STATE_THUMB:
 198                                 case ARM_STATE_THUMB_EE:
 199                                         value -= 4;
 200                                         break;
 201                                 case ARM_STATE_JAZELLE:
 202                                         /* core-specific ... ? */
 203                                         LOG_WARNING("Jazelle PC adjustment unknown");
 204                                         break;
 205                                 default:
 206                                         LOG_WARNING("unknow core state");
 207                                         break;
 208                         }
 209                         break;
 210                 case ARM_VFP_V3_D0 ... ARM_VFP_V3_D31:
 211                         return dpm_read_reg_u64(dpm, r, regnum);
 212                         break;
 213                 case ARM_VFP_V3_FPSCR:
 214                         /* "VMRS r0, FPSCR"; then return via DCC */
 215                         retval = dpm->instr_read_data_r0(dpm,
 216                                 ARMV4_5_VMRS(0), &value);
 217                         break;
 218                 default:
 219                         /* 16: "MRS r0, CPSR"; then return via DCC
 220                          * 17: "MRS r0, SPSR"; then return via DCC
 221                          */
 222                         retval = dpm->instr_read_data_r0(dpm,
 223                                 ARMV4_5_MRS(0, regnum & 1),
 224                                 &value);
 225                         break;
 226         }
 227
 228         if (retval == ERROR_OK) {
 229                 buf_set_u32(r->value, 0, 32, value);
 230                 r->valid = true;
 231                 r->dirty = false;
 232                 LOG_DEBUG("READ: %s, %8.8x", r->name, (unsigned) value);
 233         }
 234
 235         return retval;
 236 }
 237
 238 /* Write 64bit VFP registers */
 239 static int dpm_write_reg_u64(struct arm_dpm *dpm, struct reg *r, unsigned regnum)
 240 {
 241         int retval = ERROR_FAIL;
 242         uint32_t value_r0 = buf_get_u32(r->value, 0, 32);
 243         uint32_t value_r1 = buf_get_u32(r->value + 4, 0, 32);
 244
 245         switch (regnum) {
 246                 case ARM_VFP_V3_D0 ... ARM_VFP_V3_D31:
 247                         /* write value_r1 to r1 via dcc */
 248                         retval = dpm->instr_write_data_dcc(dpm,
 249                                 ARMV4_5_MRC(14, 0, 1, 0, 5, 0),
 250                                 value_r1);
 251                         /* write value_r0 to r0 via dcc then,
 252                          * move to double word register from r0:r1: "vmov vm, r0, r1"
 253                          */
 254                         retval = dpm->instr_write_data_r0(dpm,
 255                                 ARMV4_5_VMOV(0, 1, 0, ((regnum - ARM_VFP_V3_D0) >> 4),
 256                                 ((regnum - ARM_VFP_V3_D0) & 0xf)), value_r0);
 257                         break;
 258                 default:
 259
 260                         break;
 261         }
 262
 263         if (retval == ERROR_OK) {
 264                 r->dirty = false;
 265                 LOG_DEBUG("WRITE: %s, %8.8x, %8.8x", r->name,
 266                                 (unsigned) value_r0, (unsigned) value_r1);
 267         }
 268
 269         return retval;
 270 }
 271
 272 /* just write the register -- rely on the core mode being right */
 273 static int dpm_write_reg(struct arm_dpm *dpm, struct reg *r, unsigned regnum)
 274 {
 275         int retval;
 276         uint32_t value = buf_get_u32(r->value, 0, 32);
 277
 278         switch (regnum) {
 279                 case 0 ... 14:
 280                         /* load register from DCC:  "MRC p14, 0, Rnum, c0, c5, 0" */
 281                         retval = dpm->instr_write_data_dcc(dpm,
 282                                 ARMV4_5_MRC(14, 0, regnum, 0, 5, 0),
 283                                 value);
 284                         break;
 285                 case 15:/* PC
 286                          * read r0 from DCC; then "MOV pc, r0" */
 287                         retval = dpm->instr_write_data_r0(dpm, 0xe1a0f000, value);
 288                         break;
 289                 case ARM_VFP_V3_D0 ... ARM_VFP_V3_D31:
 290                         return dpm_write_reg_u64(dpm, r, regnum);
 291                         break;
 292                 case ARM_VFP_V3_FPSCR:
 293                         /* move to r0 from DCC, then "VMSR FPSCR, r0" */
 294                         retval = dpm->instr_write_data_r0(dpm,
 295                                 ARMV4_5_VMSR(0), value);
 296                         break;
 297                 default:
 298                         /* 16: read r0 from DCC, then "MSR r0, CPSR_cxsf"
 299                          * 17: read r0 from DCC, then "MSR r0, SPSR_cxsf"
 300                          */
 301                         retval = dpm->instr_write_data_r0(dpm,
 302                                 ARMV4_5_MSR_GP(0, 0xf, regnum & 1),
 303                                 value);
 304                         if (retval != ERROR_OK)
 305                                 return retval;
 306
 307                         if (regnum == 16 && dpm->instr_cpsr_sync)
 308                                 retval = dpm->instr_cpsr_sync(dpm);
 309
 310                         break;
 311         }
 312
 313         if (retval == ERROR_OK) {
 314                 r->dirty = false;
 315                 LOG_DEBUG("WRITE: %s, %8.8x", r->name, (unsigned) value);
 316         }
 317
 318         return retval;
 319 }
 320
 321 /**
 322  * Write to program counter and switch the core state (arm/thumb) according to
 323  * the address.
 324  */
 325 static int dpm_write_pc_core_state(struct arm_dpm *dpm, struct reg *r)
 326 {
 327         uint32_t value = buf_get_u32(r->value, 0, 32);
 328
 329         /* read r0 from DCC; then "BX r0" */
 330         return dpm->instr_write_data_r0(dpm, ARMV4_5_BX(0), value);
 331 }
 332
 333 /**
 334  * Read basic registers of the the current context:  R0 to R15, and CPSR;
 335  * sets the core mode (such as USR or IRQ) and state (such as ARM or Thumb).
 336  * In normal operation this is called on entry to halting debug state,
 337  * possibly after some other operations supporting restore of debug state
 338  * or making sure the CPU is fully idle (drain write buffer, etc).
 339  */
 340 int arm_dpm_read_current_registers(struct arm_dpm *dpm)
 341 {
 342         struct arm *arm = dpm->arm;
 343         uint32_t cpsr;
 344         int retval;
 345         struct reg *r;
 346
 347         retval = dpm->prepare(dpm);
 348         if (retval != ERROR_OK)
 349                 return retval;
 350
 351         /* read R0 and R1 first (it's used for scratch), then CPSR */
 352         for (unsigned i = 0; i < 2; i++) {
 353                 r = arm->core_cache->reg_list + i;
 354                 if (!r->valid) {
 355                         retval = dpm_read_reg(dpm, r, i);
 356                         if (retval != ERROR_OK)
 357                                 goto fail;
 358                 }
 359                 r->dirty = true;
 360         }
 361
 362         retval = dpm->instr_read_data_r0(dpm, ARMV4_5_MRS(0, 0), &cpsr);
 363         if (retval != ERROR_OK)
 364                 goto fail;
 365
 366         /* update core mode and state, plus shadow mapping for R8..R14 */
 367         arm_set_cpsr(arm, cpsr);
 368
 369         /* REVISIT we can probably avoid reading R1..R14, saving time... */
 370         for (unsigned i = 2; i < 16; i++) {
 371                 r = arm_reg_current(arm, i);
 372                 if (r->valid)
 373                         continue;
 374
 375                 retval = dpm_read_reg(dpm, r, i);
 376                 if (retval != ERROR_OK)
 377                         goto fail;
 378         }
 379
 380         /* NOTE: SPSR ignored (if it's even relevant). */
 381
 382         /* REVISIT the debugger can trigger various exceptions.  See the
 383          * ARMv7A architecture spec, section C5.7, for more info about
 384          * what defenses are needed; v6 debug has the most issues.
 385          */
 386
 387 fail:
 388         /* (void) */ dpm->finish(dpm);
 389         return retval;
 390 }
 391
 392 /* Avoid needless I/O ... leave breakpoints and watchpoints alone
 393  * unless they're removed, or need updating because of single-stepping
 394  * or running debugger code.
 395  */
 396 static int dpm_maybe_update_bpwp(struct arm_dpm *dpm, bool bpwp,
 397         struct dpm_bpwp *xp, int *set_p)
 398 {
 399         int retval = ERROR_OK;
 400         bool disable;
 401
 402         if (!set_p) {
 403                 if (!xp->dirty)
 404                         goto done;
 405                 xp->dirty = false;
 406                 /* removed or startup; we must disable it */
 407                 disable = true;
 408         } else if (bpwp) {
 409                 if (!xp->dirty)
 410                         goto done;
 411                 /* disabled, but we must set it */
 412                 xp->dirty = disable = false;
 413                 *set_p = true;
 414         } else {
 415                 if (!*set_p)
 416                         goto done;
 417                 /* set, but we must temporarily disable it */
 418                 xp->dirty = disable = true;
 419                 *set_p = false;
 420         }
 421
 422         if (disable)
 423                 retval = dpm->bpwp_disable(dpm, xp->number);
 424         else
 425                 retval = dpm->bpwp_enable(dpm, xp->number,
 426                                 xp->address, xp->control);
 427
 428         if (retval != ERROR_OK)
 429                 LOG_ERROR("%s: can't %s HW %spoint %d",
 430                         disable ? "disable" : "enable",
 431                         target_name(dpm->arm->target),
 432                         (xp->number < 16) ? "break" : "watch",
 433                         xp->number & 0xf);
 434 done:
 435         return retval;
 436 }
 437
 438 static int dpm_add_breakpoint(struct target *target, struct breakpoint *bp);
 439
 440 /**
 441  * Writes all modified core registers for all processor modes.  In normal
 442  * operation this is called on exit from halting debug state.
 443  *
 444  * @param dpm: represents the processor
 445  * @param bpwp: true ensures breakpoints and watchpoints are set,
 446  *      false ensures they are cleared
 447  */
 448 int arm_dpm_write_dirty_registers(struct arm_dpm *dpm, bool bpwp)
 449 {
 450         struct arm *arm = dpm->arm;
 451         struct reg_cache *cache = arm->core_cache;
 452         int retval;
 453         bool did_write;
 454
 455         retval = dpm->prepare(dpm);
 456         if (retval != ERROR_OK)
 457                 goto done;
 458
 459         /* If we're managing hardware breakpoints for this core, enable
 460          * or disable them as requested.
 461          *
 462          * REVISIT We don't yet manage them for ANY cores.  Eventually
 463          * we should be able to assume we handle them; but until then,
 464          * cope with the hand-crafted breakpoint code.
 465          */
 466         if (arm->target->type->add_breakpoint == dpm_add_breakpoint) {
 467                 for (unsigned i = 0; i < dpm->nbp; i++) {
 468                         struct dpm_bp *dbp = dpm->dbp + i;
 469                         struct breakpoint *bp = dbp->bp;
 470
 471                         retval = dpm_maybe_update_bpwp(dpm, bpwp, &dbp->bpwp,
 472                                         bp ? &bp->set : NULL);
 473                         if (retval != ERROR_OK)
 474                                 goto done;
 475                 }
 476         }
 477
 478         /* enable/disable watchpoints */
 479         for (unsigned i = 0; i < dpm->nwp; i++) {
 480                 struct dpm_wp *dwp = dpm->dwp + i;
 481                 struct watchpoint *wp = dwp->wp;
 482
 483                 retval = dpm_maybe_update_bpwp(dpm, bpwp, &dwp->bpwp,
 484                                 wp ? &wp->set : NULL);
 485                 if (retval != ERROR_OK)
 486                         goto done;
 487         }
 488
 489         /* NOTE:  writes to breakpoint and watchpoint registers might
 490          * be queued, and need (efficient/batched) flushing later.
 491          */
 492
 493         /* Scan the registers until we find one that's both dirty and
 494          * eligible for flushing.  Flush that and everything else that
 495          * shares the same core mode setting.  Typically this won't
 496          * actually find anything to do...
 497          */
 498         do {
 499                 enum arm_mode mode = ARM_MODE_ANY;
 500
 501                 did_write = false;
 502
 503                 /* check everything except our scratch registers R0 and R1 */
 504                 for (unsigned i = 2; i < cache->num_regs; i++) {
 505                         struct arm_reg *r;
 506                         unsigned regnum;
 507
 508                         /* also skip PC, CPSR, and non-dirty */
 509                         if (i == 15)
 510                                 continue;
 511                         if (arm->cpsr == cache->reg_list + i)
 512                                 continue;
 513                         if (!cache->reg_list[i].dirty)
 514                                 continue;
 515
 516                         r = cache->reg_list[i].arch_info;
 517                         regnum = r->num;
 518
 519                         /* may need to pick and set a mode */
 520                         if (!did_write) {
 521                                 enum arm_mode tmode;
 522
 523                                 did_write = true;
 524                                 mode = tmode = r->mode;
 525
 526                                 /* cope with special cases */
 527                                 switch (regnum) {
 528                                 case 8 ... 12:
 529                                         /* r8..r12 "anything but FIQ" case;
 530                                          * we "know" core mode is accurate
 531                                          * since we haven't changed it yet
 532                                          */
 533                                         if (arm->core_mode == ARM_MODE_FIQ
 534                                             && ARM_MODE_ANY
 535                                             != mode)
 536                                                 tmode = ARM_MODE_USR;
 537                                         break;
 538                                 case 16:
 539                                         /* SPSR */
 540                                         regnum++;
 541                                         break;
 542                                 }
 543
 544                                 /* REVISIT error checks */
 545                                 if (tmode != ARM_MODE_ANY) {
 546                                         retval = dpm_modeswitch(dpm, tmode);
 547                                         if (retval != ERROR_OK)
 548                                                 goto done;
 549                                 }
 550                         }
 551                         if (r->mode != mode)
 552                                 continue;
 553
 554                         retval = dpm_write_reg(dpm,
 555                                                &cache->reg_list[i],
 556                                                regnum);
 557                         if (retval != ERROR_OK)
 558                                 goto done;
 559                 }
 560
 561         } while (did_write);
 562
 563         /* Restore original CPSR ... assuming either that we changed it,
 564          * or it's dirty.  Must write PC to ensure the return address is
 565          * defined, and must not write it before CPSR.
 566          */
 567         retval = dpm_modeswitch(dpm, ARM_MODE_ANY);
 568         if (retval != ERROR_OK)
 569                 goto done;
 570         arm->cpsr->dirty = false;
 571
 572         /* restore the PC, make sure to also switch the core state
 573          * to whatever it was set to with "arm core_state" command.
 574          * target code will have set PC to an appropriate resume address.
 575          */
 576         retval = dpm_write_pc_core_state(dpm, arm->pc);
 577         if (retval != ERROR_OK)
 578                 goto done;
 579         /* on Cortex-A5 (as found on NXP VF610 SoC), BX instruction
 580          * executed in debug state doesn't appear to set the PC,
 581          * explicitly set it with a "MOV pc, r0". This doesn't influence
 582          * CPSR on Cortex-A9 so it should be OK. Maybe due to different
 583          * debug version?
 584          */
 585         retval = dpm_write_reg(dpm, arm->pc, 15);
 586         if (retval != ERROR_OK)
 587                 goto done;
 588         arm->pc->dirty = false;
 589
 590         /* flush R0 -- it's *very* dirty by now */
 591         retval = dpm_write_reg(dpm, &cache->reg_list[0], 0);
 592         if (retval != ERROR_OK)
 593                 goto done;
 594         cache->reg_list[0].dirty = false;
 595
 596         /* (void) */ dpm->finish(dpm);
 597 done:
 598         return retval;
 599 }
 600
 601 /* Returns ARM_MODE_ANY or temporary mode to use while reading the
 602  * specified register ... works around flakiness from ARM core calls.
 603  * Caller already filtered out SPSR access; mode is never MODE_SYS
 604  * or MODE_ANY.
 605  */
 606 static enum arm_mode dpm_mapmode(struct arm *arm,
 607         unsigned num, enum arm_mode mode)
 608 {
 609         enum arm_mode amode = arm->core_mode;
 610
 611         /* don't switch if the mode is already correct */
 612         if (amode == ARM_MODE_SYS)
 613                 amode = ARM_MODE_USR;
 614         if (mode == amode)
 615                 return ARM_MODE_ANY;
 616
 617         switch (num) {
 618                 /* don't switch for non-shadowed registers (r0..r7, r15/pc, cpsr) */
 619                 case 0 ... 7:
 620                 case 15:
 621                 case 16:
 622                         break;
 623                 /* r8..r12 aren't shadowed for anything except FIQ */
 624                 case 8 ... 12:
 625                         if (mode == ARM_MODE_FIQ)
 626                                 return mode;
 627                         break;
 628                 /* r13/sp, and r14/lr are always shadowed */
 629                 case 13:
 630                 case 14:
 631                 case ARM_VFP_V3_D0 ... ARM_VFP_V3_FPSCR:
 632                         return mode;
 633                 default:
 634                         LOG_WARNING("invalid register #%u", num);
 635                         break;
 636         }
 637         return ARM_MODE_ANY;
 638 }
 639
 640
 641 /*
 642  * Standard ARM register accessors ... there are three methods
 643  * in "struct arm", to support individual read/write and bulk read
 644  * of registers.
 645  */
 646
 647 static int arm_dpm_read_core_reg(struct target *target, struct reg *r,
 648         int regnum, enum arm_mode mode)
 649 {
 650         struct arm_dpm *dpm = target_to_arm(target)->dpm;
 651         int retval;
 652
 653         if (regnum < 0 || (regnum > 16 && regnum < ARM_VFP_V3_D0) ||
 654                 (regnum > ARM_VFP_V3_FPSCR))
 655                 return ERROR_COMMAND_SYNTAX_ERROR;
 656
 657         if (regnum == 16) {
 658                 if (mode != ARM_MODE_ANY)
 659                         regnum = 17;
 660         } else
 661                 mode = dpm_mapmode(dpm->arm, regnum, mode);
 662
 663         /* REVISIT what happens if we try to read SPSR in a core mode
 664          * which has no such register?
 665          */
 666
 667         retval = dpm->prepare(dpm);
 668         if (retval != ERROR_OK)
 669                 return retval;
 670
 671         if (mode != ARM_MODE_ANY) {
 672                 retval = dpm_modeswitch(dpm, mode);
 673                 if (retval != ERROR_OK)
 674                         goto fail;
 675         }
 676
 677         retval = dpm_read_reg(dpm, r, regnum);
 678         if (retval != ERROR_OK)
 679                 goto fail;
 680         /* always clean up, regardless of error */
 681
 682         if (mode != ARM_MODE_ANY)
 683                 /* (void) */ dpm_modeswitch(dpm, ARM_MODE_ANY);
 684
 685 fail:
 686         /* (void) */ dpm->finish(dpm);
 687         return retval;
 688 }
 689
 690 static int arm_dpm_write_core_reg(struct target *target, struct reg *r,
 691         int regnum, enum arm_mode mode, uint8_t *value)
 692 {
 693         struct arm_dpm *dpm = target_to_arm(target)->dpm;
 694         int retval;
 695
 696
 697         if (regnum < 0 || (regnum > 16 && regnum < ARM_VFP_V3_D0) ||
 698                         (regnum > ARM_VFP_V3_FPSCR))
 699                 return ERROR_COMMAND_SYNTAX_ERROR;
 700
 701         if (regnum == 16) {
 702                 if (mode != ARM_MODE_ANY)
 703                         regnum = 17;
 704         } else
 705                 mode = dpm_mapmode(dpm->arm, regnum, mode);
 706
 707         /* REVISIT what happens if we try to write SPSR in a core mode
 708          * which has no such register?
 709          */
 710
 711         retval = dpm->prepare(dpm);
 712         if (retval != ERROR_OK)
 713                 return retval;
 714
 715         if (mode != ARM_MODE_ANY) {
 716                 retval = dpm_modeswitch(dpm, mode);
 717                 if (retval != ERROR_OK)
 718                         goto fail;
 719         }
 720
 721         retval = dpm_write_reg(dpm, r, regnum);
 722         /* always clean up, regardless of error */
 723
 724         if (mode != ARM_MODE_ANY)
 725                 /* (void) */ dpm_modeswitch(dpm, ARM_MODE_ANY);
 726
 727 fail:
 728         /* (void) */ dpm->finish(dpm);
 729         return retval;
 730 }
 731
 732 static int arm_dpm_full_context(struct target *target)
 733 {
 734         struct arm *arm = target_to_arm(target);
 735         struct arm_dpm *dpm = arm->dpm;
 736         struct reg_cache *cache = arm->core_cache;
 737         int retval;
 738         bool did_read;
 739
 740         retval = dpm->prepare(dpm);
 741         if (retval != ERROR_OK)
 742                 goto done;
 743
 744         do {
 745                 enum arm_mode mode = ARM_MODE_ANY;
 746
 747                 did_read = false;
 748
 749                 /* We "know" arm_dpm_read_current_registers() was called so
 750                  * the unmapped registers (R0..R7, PC, AND CPSR) and some
 751                  * view of R8..R14 are current.  We also "know" oddities of
 752                  * register mapping: special cases for R8..R12 and SPSR.
 753                  *
 754                  * Pick some mode with unread registers and read them all.
 755                  * Repeat until done.
 756                  */
 757                 for (unsigned i = 0; i < cache->num_regs; i++) {
 758                         struct arm_reg *r;
 759
 760                         if (cache->reg_list[i].valid)
 761                                 continue;
 762                         r = cache->reg_list[i].arch_info;
 763
 764                         /* may need to pick a mode and set CPSR */
 765                         if (!did_read) {
 766                                 did_read = true;
 767                                 mode = r->mode;
 768
 769                                 /* For regular (ARM_MODE_ANY) R8..R12
 770                                  * in case we've entered debug state
 771                                  * in FIQ mode we need to patch mode.
 772                                  */
 773                                 if (mode != ARM_MODE_ANY)
 774                                         retval = dpm_modeswitch(dpm, mode);
 775                                 else
 776                                         retval = dpm_modeswitch(dpm, ARM_MODE_USR);
 777
 778                                 if (retval != ERROR_OK)
 779                                         goto done;
 780                         }
 781                         if (r->mode != mode)
 782                                 continue;
 783
 784                         /* CPSR was read, so "R16" must mean SPSR */
 785                         retval = dpm_read_reg(dpm,
 786                                         &cache->reg_list[i],
 787                                         (r->num == 16) ? 17 : r->num);
 788                         if (retval != ERROR_OK)
 789                                 goto done;
 790                 }
 791
 792         } while (did_read);
 793
 794         retval = dpm_modeswitch(dpm, ARM_MODE_ANY);
 795         /* (void) */ dpm->finish(dpm);
 796 done:
 797         return retval;
 798 }
 799
 800
 801 /*----------------------------------------------------------------------*/
 802
 803 /*
 804  * Breakpoint and Watchpoint support.
 805  *
 806  * Hardware {break,watch}points are usually left active, to minimize
 807  * debug entry/exit costs.  When they are set or cleared, it's done in
 808  * batches.  Also, DPM-conformant hardware can update debug registers
 809  * regardless of whether the CPU is running or halted ... though that
 810  * fact isn't currently leveraged.
 811  */
 812
 813 static int dpm_bpwp_setup(struct arm_dpm *dpm, struct dpm_bpwp *xp,
 814         uint32_t addr, uint32_t length)
 815 {
 816         uint32_t control;
 817
 818         control = (1 << 0)      /* enable */
 819                 | (3 << 1);     /* both user and privileged access */
 820
 821         /* Match 1, 2, or all 4 byte addresses in this word.
 822          *
 823          * FIXME:  v7 hardware allows lengths up to 2 GB for BP and WP.
 824          * Support larger length, when addr is suitably aligned.  In
 825          * particular, allow watchpoints on 8 byte "double" values.
 826          *
 827          * REVISIT allow watchpoints on unaligned 2-bit values; and on
 828          * v7 hardware, unaligned 4-byte ones too.
 829          */
 830         switch (length) {
 831                 case 1:
 832                         control |= (1 << (addr & 3)) << 5;
 833                         break;
 834                 case 2:
 835                         /* require 2-byte alignment */
 836                         if (!(addr & 1)) {
 837                                 control |= (3 << (addr & 2)) << 5;
 838                                 break;
 839                         }
 840                 /* FALL THROUGH */
 841                 case 4:
 842                         /* require 4-byte alignment */
 843                         if (!(addr & 3)) {
 844                                 control |= 0xf << 5;
 845                                 break;
 846                         }
 847                 /* FALL THROUGH */
 848                 default:
 849                         LOG_ERROR("unsupported {break,watch}point length/alignment");
 850                         return ERROR_COMMAND_SYNTAX_ERROR;
 851         }
 852
 853         /* other shared control bits:
 854          * bits 15:14 == 0 ... both secure and nonsecure states (v6.1+ only)
 855          * bit 20 == 0 ... not linked to a context ID
 856          * bit 28:24 == 0 ... not ignoring N LSBs (v7 only)
 857          */
 858
 859         xp->address = addr & ~3;
 860         xp->control = control;
 861         xp->dirty = true;
 862
 863         LOG_DEBUG("BPWP: addr %8.8" PRIx32 ", control %" PRIx32 ", number %d",
 864                 xp->address, control, xp->number);
 865
 866         /* hardware is updated in write_dirty_registers() */
 867         return ERROR_OK;
 868 }
 869
 870 static int dpm_add_breakpoint(struct target *target, struct breakpoint *bp)
 871 {
 872         struct arm *arm = target_to_arm(target);
 873         struct arm_dpm *dpm = arm->dpm;
 874         int retval = ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
 875
 876         if (bp->length < 2)
 877                 return ERROR_COMMAND_SYNTAX_ERROR;
 878         if (!dpm->bpwp_enable)
 879                 return retval;
 880
 881         /* FIXME we need a generic solution for software breakpoints. */
 882         if (bp->type == BKPT_SOFT)
 883                 LOG_DEBUG("using HW bkpt, not SW...");
 884
 885         for (unsigned i = 0; i < dpm->nbp; i++) {
 886                 if (!dpm->dbp[i].bp) {
 887                         retval = dpm_bpwp_setup(dpm, &dpm->dbp[i].bpwp,
 888                                         bp->address, bp->length);
 889                         if (retval == ERROR_OK)
 890                                 dpm->dbp[i].bp = bp;
 891                         break;
 892                 }
 893         }
 894
 895         return retval;
 896 }
 897
 898 static int dpm_remove_breakpoint(struct target *target, struct breakpoint *bp)
 899 {
 900         struct arm *arm = target_to_arm(target);
 901         struct arm_dpm *dpm = arm->dpm;
 902         int retval = ERROR_COMMAND_SYNTAX_ERROR;
 903
 904         for (unsigned i = 0; i < dpm->nbp; i++) {
 905                 if (dpm->dbp[i].bp == bp) {
 906                         dpm->dbp[i].bp = NULL;
 907                         dpm->dbp[i].bpwp.dirty = true;
 908
 909                         /* hardware is updated in write_dirty_registers() */
 910                         retval = ERROR_OK;
 911                         break;
 912                 }
 913         }
 914
 915         return retval;
 916 }
 917
 918 static int dpm_watchpoint_setup(struct arm_dpm *dpm, unsigned index_t,
 919         struct watchpoint *wp)
 920 {
 921         int retval;
 922         struct dpm_wp *dwp = dpm->dwp + index_t;
 923         uint32_t control;
 924
 925         /* this hardware doesn't support data value matching or masking */
 926         if (wp->value || wp->mask != ~(uint32_t)0) {
 927                 LOG_DEBUG("watchpoint values and masking not supported");
 928                 return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
 929         }
 930
 931         retval = dpm_bpwp_setup(dpm, &dwp->bpwp, wp->address, wp->length);
 932         if (retval != ERROR_OK)
 933                 return retval;
 934
 935         control = dwp->bpwp.control;
 936         switch (wp->rw) {
 937                 case WPT_READ:
 938                         control |= 1 << 3;
 939                         break;
 940                 case WPT_WRITE:
 941                         control |= 2 << 3;
 942                         break;
 943                 case WPT_ACCESS:
 944                         control |= 3 << 3;
 945                         break;
 946         }
 947         dwp->bpwp.control = control;
 948
 949         dpm->dwp[index_t].wp = wp;
 950
 951         return retval;
 952 }
 953
 954 static int dpm_add_watchpoint(struct target *target, struct watchpoint *wp)
 955 {
 956         struct arm *arm = target_to_arm(target);
 957         struct arm_dpm *dpm = arm->dpm;
 958         int retval = ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
 959
 960         if (dpm->bpwp_enable) {
 961                 for (unsigned i = 0; i < dpm->nwp; i++) {
 962                         if (!dpm->dwp[i].wp) {
 963                                 retval = dpm_watchpoint_setup(dpm, i, wp);
 964                                 break;
 965                         }
 966                 }
 967         }
 968
 969         return retval;
 970 }
 971
 972 static int dpm_remove_watchpoint(struct target *target, struct watchpoint *wp)
 973 {
 974         struct arm *arm = target_to_arm(target);
 975         struct arm_dpm *dpm = arm->dpm;
 976         int retval = ERROR_COMMAND_SYNTAX_ERROR;
 977
 978         for (unsigned i = 0; i < dpm->nwp; i++) {
 979                 if (dpm->dwp[i].wp == wp) {
 980                         dpm->dwp[i].wp = NULL;
 981                         dpm->dwp[i].bpwp.dirty = true;
 982
 983                         /* hardware is updated in write_dirty_registers() */
 984                         retval = ERROR_OK;
 985                         break;
 986                 }
 987         }
 988
 989         return retval;
 990 }
 991
 992 void arm_dpm_report_wfar(struct arm_dpm *dpm, uint32_t addr)
 993 {
 994         switch (dpm->arm->core_state) {
 995                 case ARM_STATE_ARM:
 996                         addr -= 8;
 997                         break;
 998                 case ARM_STATE_THUMB:
 999                 case ARM_STATE_THUMB_EE:
1000                         addr -= 4;
1001                         break;
1002                 case ARM_STATE_JAZELLE:
1003                 case ARM_STATE_AARCH64:
1004                         /* ?? */
1005                         break;
1006         }
1007         dpm->wp_pc = addr;
1008 }
1009
1010 /*----------------------------------------------------------------------*/
1011
1012 /*
1013  * Other debug and support utilities
1014  */
1015
1016 void arm_dpm_report_dscr(struct arm_dpm *dpm, uint32_t dscr)
1017 {
1018         struct target *target = dpm->arm->target;
1019
1020         dpm->dscr = dscr;
1021
1022         /* Examine debug reason */
1023         switch (DSCR_ENTRY(dscr)) {
1024                 case DSCR_ENTRY_HALT_REQ:       /* HALT request from debugger */
1025                 case DSCR_ENTRY_EXT_DBG_REQ:    /* EDBGRQ */
1026                         target->debug_reason = DBG_REASON_DBGRQ;
1027                         break;
1028                 case DSCR_ENTRY_BREAKPOINT:     /* HW breakpoint */
1029                 case DSCR_ENTRY_BKPT_INSTR:     /* vector catch */
1030                         target->debug_reason = DBG_REASON_BREAKPOINT;
1031                         break;
1032                 case DSCR_ENTRY_IMPRECISE_WATCHPT:      /* asynch watchpoint */
1033                 case DSCR_ENTRY_PRECISE_WATCHPT:/* precise watchpoint */
1034                         target->debug_reason = DBG_REASON_WATCHPOINT;
1035                         break;
1036                 default:
1037                         target->debug_reason = DBG_REASON_UNDEFINED;
1038                         break;
1039         }
1040 }
1041
1042 /*----------------------------------------------------------------------*/
1043
1044 /*
1045  * Setup and management support.
1046  */
1047
1048 /**
1049  * Hooks up this DPM to its associated target; call only once.
1050  * Initially this only covers the register cache.
1051  *
1052  * Oh, and watchpoints.  Yeah.
1053  */
1054 int arm_dpm_setup(struct arm_dpm *dpm)
1055 {
1056         struct arm *arm = dpm->arm;
1057         struct target *target = arm->target;
1058         struct reg_cache *cache = 0;
1059
1060         arm->dpm = dpm;
1061
1062         /* register access setup */
1063         arm->full_context = arm_dpm_full_context;
1064         arm->read_core_reg = arm_dpm_read_core_reg;
1065         arm->write_core_reg = arm_dpm_write_core_reg;
1066
1067         if (arm->core_cache == NULL) {
1068                 cache = arm_build_reg_cache(target, arm);
1069                 if (!cache)
1070                         return ERROR_FAIL;
1071
1072                 *register_get_last_cache_p(&target->reg_cache) = cache;
1073         }
1074
1075         /* coprocessor access setup */
1076         arm->mrc = dpm_mrc;
1077         arm->mcr = dpm_mcr;
1078
1079         /* breakpoint setup -- optional until it works everywhere */
1080         if (!target->type->add_breakpoint) {
1081                 target->type->add_breakpoint = dpm_add_breakpoint;
1082                 target->type->remove_breakpoint = dpm_remove_breakpoint;
1083         }
1084
1085         /* watchpoint setup */
1086         target->type->add_watchpoint = dpm_add_watchpoint;
1087         target->type->remove_watchpoint = dpm_remove_watchpoint;
1088
1089         /* FIXME add vector catch support */
1090
1091         dpm->nbp = 1 + ((dpm->didr >> 24) & 0xf);
1092         dpm->nwp = 1 + ((dpm->didr >> 28) & 0xf);
1093         dpm->dbp = calloc(dpm->nbp, sizeof *dpm->dbp);
1094         dpm->dwp = calloc(dpm->nwp, sizeof *dpm->dwp);
1095
1096         if (!dpm->dbp || !dpm->dwp) {
1097                 free(dpm->dbp);
1098                 free(dpm->dwp);
1099                 return ERROR_FAIL;
1100         }
1101
1102         LOG_INFO("%s: hardware has %d breakpoints, %d watchpoints",
1103                 target_name(target), dpm->nbp, dpm->nwp);
1104
1105         /* REVISIT ... and some of those breakpoints could match
1106          * execution context IDs...
1107          */
1108
1109         return ERROR_OK;
1110 }
1111
1112 /**
1113  * Reinitializes DPM state at the beginning of a new debug session
1114  * or after a reset which may have affected the debug module.
1115  */
1116 int arm_dpm_initialize(struct arm_dpm *dpm)
1117 {
1118         /* Disable all breakpoints and watchpoints at startup. */
1119         if (dpm->bpwp_disable) {
1120                 unsigned i;
1121
1122                 for (i = 0; i < dpm->nbp; i++) {
1123                         dpm->dbp[i].bpwp.number = i;
1124                         (void) dpm->bpwp_disable(dpm, i);
1125                 }
1126                 for (i = 0; i < dpm->nwp; i++) {
1127                         dpm->dwp[i].bpwp.number = 16 + i;
1128                         (void) dpm->bpwp_disable(dpm, 16 + i);
1129                 }
1130         } else
1131                 LOG_WARNING("%s: can't disable breakpoints and watchpoints",
1132                         target_name(dpm->arm->target));
1133
1134         return ERROR_OK;
1135 }