arch/powerpc/kernel/ptrace/ptrace-adv.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2
   3 #include <linux/regset.h>
   4 #include <linux/hw_breakpoint.h>
   5
   6 #include "ptrace-decl.h"
   7
   8 void user_enable_single_step(struct task_struct *task)
   9 {
  10         struct pt_regs *regs = task->thread.regs;
  11
  12         if (regs != NULL) {
  13                 task->thread.debug.dbcr0 &= ~DBCR0_BT;
  14                 task->thread.debug.dbcr0 |= DBCR0_IDM | DBCR0_IC;
  15                 regs_set_return_msr(regs, regs->msr | MSR_DE);
  16         }
  17         set_tsk_thread_flag(task, TIF_SINGLESTEP);
  18 }
  19
  20 void user_enable_block_step(struct task_struct *task)
  21 {
  22         struct pt_regs *regs = task->thread.regs;
  23
  24         if (regs != NULL) {
  25                 task->thread.debug.dbcr0 &= ~DBCR0_IC;
  26                 task->thread.debug.dbcr0 = DBCR0_IDM | DBCR0_BT;
  27                 regs_set_return_msr(regs, regs->msr | MSR_DE);
  28         }
  29         set_tsk_thread_flag(task, TIF_SINGLESTEP);
  30 }
  31
  32 void user_disable_single_step(struct task_struct *task)
  33 {
  34         struct pt_regs *regs = task->thread.regs;
  35
  36         if (regs != NULL) {
  37                 /*
  38                  * The logic to disable single stepping should be as
  39                  * simple as turning off the Instruction Complete flag.
  40                  * And, after doing so, if all debug flags are off, turn
  41                  * off DBCR0(IDM) and MSR(DE) .... Torez
  42                  */
  43                 task->thread.debug.dbcr0 &= ~(DBCR0_IC | DBCR0_BT);
  44                 /*
  45                  * Test to see if any of the DBCR_ACTIVE_EVENTS bits are set.
  46                  */
  47                 if (!DBCR_ACTIVE_EVENTS(task->thread.debug.dbcr0,
  48                                         task->thread.debug.dbcr1)) {
  49                         /*
  50                          * All debug events were off.....
  51                          */
  52                         task->thread.debug.dbcr0 &= ~DBCR0_IDM;
  53                         regs_set_return_msr(regs, regs->msr & ~MSR_DE);
  54                 }
  55         }
  56         clear_tsk_thread_flag(task, TIF_SINGLESTEP);
  57 }
  58
  59 void ppc_gethwdinfo(struct ppc_debug_info *dbginfo)
  60 {
  61         dbginfo->version = 1;
  62         dbginfo->num_instruction_bps = CONFIG_PPC_ADV_DEBUG_IACS;
  63         dbginfo->num_data_bps = CONFIG_PPC_ADV_DEBUG_DACS;
  64         dbginfo->num_condition_regs = CONFIG_PPC_ADV_DEBUG_DVCS;
  65         dbginfo->data_bp_alignment = 4;
  66         dbginfo->sizeof_condition = 4;
  67         dbginfo->features = PPC_DEBUG_FEATURE_INSN_BP_RANGE |
  68                             PPC_DEBUG_FEATURE_INSN_BP_MASK;
  69         if (IS_ENABLED(CONFIG_PPC_ADV_DEBUG_DAC_RANGE))
  70                 dbginfo->features |= PPC_DEBUG_FEATURE_DATA_BP_RANGE |
  71                                      PPC_DEBUG_FEATURE_DATA_BP_MASK;
  72 }
  73
  74 int ptrace_get_debugreg(struct task_struct *child, unsigned long addr,
  75                         unsigned long __user *datalp)
  76 {
  77         /* We only support one DABR and no IABRS at the moment */
  78         if (addr > 0)
  79                 return -EINVAL;
  80         return put_user(child->thread.debug.dac1, datalp);
  81 }
  82
  83 int ptrace_set_debugreg(struct task_struct *task, unsigned long addr, unsigned long data)
  84 {
  85         struct pt_regs *regs = task->thread.regs;
  86 #ifdef CONFIG_HAVE_HW_BREAKPOINT
  87         int ret;
  88         struct thread_struct *thread = &task->thread;
  89         struct perf_event *bp;
  90         struct perf_event_attr attr;
  91 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
  92
  93         /* For ppc64 we support one DABR and no IABR's at the moment (ppc64).
  94          *  For embedded processors we support one DAC and no IAC's at the
  95          *  moment.
  96          */
  97         if (addr > 0)
  98                 return -EINVAL;
  99
 100         /* The bottom 3 bits in dabr are flags */
 101         if ((data & ~0x7UL) >= TASK_SIZE)
 102                 return -EIO;
 103
 104         /* As described above, it was assumed 3 bits were passed with the data
 105          *  address, but we will assume only the mode bits will be passed
 106          *  as to not cause alignment restrictions for DAC-based processors.
 107          */
 108
 109         /* DAC's hold the whole address without any mode flags */
 110         task->thread.debug.dac1 = data & ~0x3UL;
 111
 112         if (task->thread.debug.dac1 == 0) {
 113                 dbcr_dac(task) &= ~(DBCR_DAC1R | DBCR_DAC1W);
 114                 if (!DBCR_ACTIVE_EVENTS(task->thread.debug.dbcr0,
 115                                         task->thread.debug.dbcr1)) {
 116                         regs_set_return_msr(regs, regs->msr & ~MSR_DE);
 117                         task->thread.debug.dbcr0 &= ~DBCR0_IDM;
 118                 }
 119                 return 0;
 120         }
 121
 122         /* Read or Write bits must be set */
 123
 124         if (!(data & 0x3UL))
 125                 return -EINVAL;
 126
 127         /* Set the Internal Debugging flag (IDM bit 1) for the DBCR0 register */
 128         task->thread.debug.dbcr0 |= DBCR0_IDM;
 129
 130         /* Check for write and read flags and set DBCR0 accordingly */
 131         dbcr_dac(task) &= ~(DBCR_DAC1R | DBCR_DAC1W);
 132         if (data & 0x1UL)
 133                 dbcr_dac(task) |= DBCR_DAC1R;
 134         if (data & 0x2UL)
 135                 dbcr_dac(task) |= DBCR_DAC1W;
 136         regs_set_return_msr(regs, regs->msr | MSR_DE);
 137         return 0;
 138 }
 139
 140 static long set_instruction_bp(struct task_struct *child,
 141                                struct ppc_hw_breakpoint *bp_info)
 142 {
 143         int slot;
 144         int slot1_in_use = ((child->thread.debug.dbcr0 & DBCR0_IAC1) != 0);
 145         int slot2_in_use = ((child->thread.debug.dbcr0 & DBCR0_IAC2) != 0);
 146         int slot3_in_use = ((child->thread.debug.dbcr0 & DBCR0_IAC3) != 0);
 147         int slot4_in_use = ((child->thread.debug.dbcr0 & DBCR0_IAC4) != 0);
 148
 149         if (dbcr_iac_range(child) & DBCR_IAC12MODE)
 150                 slot2_in_use = 1;
 151         if (dbcr_iac_range(child) & DBCR_IAC34MODE)
 152                 slot4_in_use = 1;
 153
 154         if (bp_info->addr >= TASK_SIZE)
 155                 return -EIO;
 156
 157         if (bp_info->addr_mode != PPC_BREAKPOINT_MODE_EXACT) {
 158                 /* Make sure range is valid. */
 159                 if (bp_info->addr2 >= TASK_SIZE)
 160                         return -EIO;
 161
 162                 /* We need a pair of IAC regsisters */
 163                 if (!slot1_in_use && !slot2_in_use) {
 164                         slot = 1;
 165                         child->thread.debug.iac1 = bp_info->addr;
 166                         child->thread.debug.iac2 = bp_info->addr2;
 167                         child->thread.debug.dbcr0 |= DBCR0_IAC1;
 168                         if (bp_info->addr_mode ==
 169                                         PPC_BREAKPOINT_MODE_RANGE_EXCLUSIVE)
 170                                 dbcr_iac_range(child) |= DBCR_IAC12X;
 171                         else
 172                                 dbcr_iac_range(child) |= DBCR_IAC12I;
 173 #if CONFIG_PPC_ADV_DEBUG_IACS > 2
 174                 } else if ((!slot3_in_use) && (!slot4_in_use)) {
 175                         slot = 3;
 176                         child->thread.debug.iac3 = bp_info->addr;
 177                         child->thread.debug.iac4 = bp_info->addr2;
 178                         child->thread.debug.dbcr0 |= DBCR0_IAC3;
 179                         if (bp_info->addr_mode ==
 180                                         PPC_BREAKPOINT_MODE_RANGE_EXCLUSIVE)
 181                                 dbcr_iac_range(child) |= DBCR_IAC34X;
 182                         else
 183                                 dbcr_iac_range(child) |= DBCR_IAC34I;
 184 #endif
 185                 } else {
 186                         return -ENOSPC;
 187                 }
 188         } else {
 189                 /* We only need one.  If possible leave a pair free in
 190                  * case a range is needed later
 191                  */
 192                 if (!slot1_in_use) {
 193                         /*
 194                          * Don't use iac1 if iac1-iac2 are free and either
 195                          * iac3 or iac4 (but not both) are free
 196                          */
 197                         if (slot2_in_use || slot3_in_use == slot4_in_use) {
 198                                 slot = 1;
 199                                 child->thread.debug.iac1 = bp_info->addr;
 200                                 child->thread.debug.dbcr0 |= DBCR0_IAC1;
 201                                 goto out;
 202                         }
 203                 }
 204                 if (!slot2_in_use) {
 205                         slot = 2;
 206                         child->thread.debug.iac2 = bp_info->addr;
 207                         child->thread.debug.dbcr0 |= DBCR0_IAC2;
 208 #if CONFIG_PPC_ADV_DEBUG_IACS > 2
 209                 } else if (!slot3_in_use) {
 210                         slot = 3;
 211                         child->thread.debug.iac3 = bp_info->addr;
 212                         child->thread.debug.dbcr0 |= DBCR0_IAC3;
 213                 } else if (!slot4_in_use) {
 214                         slot = 4;
 215                         child->thread.debug.iac4 = bp_info->addr;
 216                         child->thread.debug.dbcr0 |= DBCR0_IAC4;
 217 #endif
 218                 } else {
 219                         return -ENOSPC;
 220                 }
 221         }
 222 out:
 223         child->thread.debug.dbcr0 |= DBCR0_IDM;
 224         regs_set_return_msr(child->thread.regs, child->thread.regs->msr | MSR_DE);
 225
 226         return slot;
 227 }
 228
 229 static int del_instruction_bp(struct task_struct *child, int slot)
 230 {
 231         switch (slot) {
 232         case 1:
 233                 if ((child->thread.debug.dbcr0 & DBCR0_IAC1) == 0)
 234                         return -ENOENT;
 235
 236                 if (dbcr_iac_range(child) & DBCR_IAC12MODE) {
 237                         /* address range - clear slots 1 & 2 */
 238                         child->thread.debug.iac2 = 0;
 239                         dbcr_iac_range(child) &= ~DBCR_IAC12MODE;
 240                 }
 241                 child->thread.debug.iac1 = 0;
 242                 child->thread.debug.dbcr0 &= ~DBCR0_IAC1;
 243                 break;
 244         case 2:
 245                 if ((child->thread.debug.dbcr0 & DBCR0_IAC2) == 0)
 246                         return -ENOENT;
 247
 248                 if (dbcr_iac_range(child) & DBCR_IAC12MODE)
 249                         /* used in a range */
 250                         return -EINVAL;
 251                 child->thread.debug.iac2 = 0;
 252                 child->thread.debug.dbcr0 &= ~DBCR0_IAC2;
 253                 break;
 254 #if CONFIG_PPC_ADV_DEBUG_IACS > 2
 255         case 3:
 256                 if ((child->thread.debug.dbcr0 & DBCR0_IAC3) == 0)
 257                         return -ENOENT;
 258
 259                 if (dbcr_iac_range(child) & DBCR_IAC34MODE) {
 260                         /* address range - clear slots 3 & 4 */
 261                         child->thread.debug.iac4 = 0;
 262                         dbcr_iac_range(child) &= ~DBCR_IAC34MODE;
 263                 }
 264                 child->thread.debug.iac3 = 0;
 265                 child->thread.debug.dbcr0 &= ~DBCR0_IAC3;
 266                 break;
 267         case 4:
 268                 if ((child->thread.debug.dbcr0 & DBCR0_IAC4) == 0)
 269                         return -ENOENT;
 270
 271                 if (dbcr_iac_range(child) & DBCR_IAC34MODE)
 272                         /* Used in a range */
 273                         return -EINVAL;
 274                 child->thread.debug.iac4 = 0;
 275                 child->thread.debug.dbcr0 &= ~DBCR0_IAC4;
 276                 break;
 277 #endif
 278         default:
 279                 return -EINVAL;
 280         }
 281         return 0;
 282 }
 283
 284 static int set_dac(struct task_struct *child, struct ppc_hw_breakpoint *bp_info)
 285 {
 286         int byte_enable =
 287                 (bp_info->condition_mode >> PPC_BREAKPOINT_CONDITION_BE_SHIFT)
 288                 & 0xf;
 289         int condition_mode =
 290                 bp_info->condition_mode & PPC_BREAKPOINT_CONDITION_MODE;
 291         int slot;
 292
 293         if (byte_enable && condition_mode == 0)
 294                 return -EINVAL;
 295
 296         if (bp_info->addr >= TASK_SIZE)
 297                 return -EIO;
 298
 299         if ((dbcr_dac(child) & (DBCR_DAC1R | DBCR_DAC1W)) == 0) {
 300                 slot = 1;
 301                 if (bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_READ)
 302                         dbcr_dac(child) |= DBCR_DAC1R;
 303                 if (bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_WRITE)
 304                         dbcr_dac(child) |= DBCR_DAC1W;
 305                 child->thread.debug.dac1 = (unsigned long)bp_info->addr;
 306 #if CONFIG_PPC_ADV_DEBUG_DVCS > 0
 307                 if (byte_enable) {
 308                         child->thread.debug.dvc1 =
 309                                 (unsigned long)bp_info->condition_value;
 310                         child->thread.debug.dbcr2 |=
 311                                 ((byte_enable << DBCR2_DVC1BE_SHIFT) |
 312                                  (condition_mode << DBCR2_DVC1M_SHIFT));
 313                 }
 314 #endif
 315 #ifdef CONFIG_PPC_ADV_DEBUG_DAC_RANGE
 316         } else if (child->thread.debug.dbcr2 & DBCR2_DAC12MODE) {
 317                 /* Both dac1 and dac2 are part of a range */
 318                 return -ENOSPC;
 319 #endif
 320         } else if ((dbcr_dac(child) & (DBCR_DAC2R | DBCR_DAC2W)) == 0) {
 321                 slot = 2;
 322                 if (bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_READ)
 323                         dbcr_dac(child) |= DBCR_DAC2R;
 324                 if (bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_WRITE)
 325                         dbcr_dac(child) |= DBCR_DAC2W;
 326                 child->thread.debug.dac2 = (unsigned long)bp_info->addr;
 327 #if CONFIG_PPC_ADV_DEBUG_DVCS > 0
 328                 if (byte_enable) {
 329                         child->thread.debug.dvc2 =
 330                                 (unsigned long)bp_info->condition_value;
 331                         child->thread.debug.dbcr2 |=
 332                                 ((byte_enable << DBCR2_DVC2BE_SHIFT) |
 333                                  (condition_mode << DBCR2_DVC2M_SHIFT));
 334                 }
 335 #endif
 336         } else {
 337                 return -ENOSPC;
 338         }
 339         child->thread.debug.dbcr0 |= DBCR0_IDM;
 340         regs_set_return_msr(child->thread.regs, child->thread.regs->msr | MSR_DE);
 341
 342         return slot + 4;
 343 }
 344
 345 static int del_dac(struct task_struct *child, int slot)
 346 {
 347         if (slot == 1) {
 348                 if ((dbcr_dac(child) & (DBCR_DAC1R | DBCR_DAC1W)) == 0)
 349                         return -ENOENT;
 350
 351                 child->thread.debug.dac1 = 0;
 352                 dbcr_dac(child) &= ~(DBCR_DAC1R | DBCR_DAC1W);
 353 #ifdef CONFIG_PPC_ADV_DEBUG_DAC_RANGE
 354                 if (child->thread.debug.dbcr2 & DBCR2_DAC12MODE) {
 355                         child->thread.debug.dac2 = 0;
 356                         child->thread.debug.dbcr2 &= ~DBCR2_DAC12MODE;
 357                 }
 358                 child->thread.debug.dbcr2 &= ~(DBCR2_DVC1M | DBCR2_DVC1BE);
 359 #endif
 360 #if CONFIG_PPC_ADV_DEBUG_DVCS > 0
 361                 child->thread.debug.dvc1 = 0;
 362 #endif
 363         } else if (slot == 2) {
 364                 if ((dbcr_dac(child) & (DBCR_DAC2R | DBCR_DAC2W)) == 0)
 365                         return -ENOENT;
 366
 367 #ifdef CONFIG_PPC_ADV_DEBUG_DAC_RANGE
 368                 if (child->thread.debug.dbcr2 & DBCR2_DAC12MODE)
 369                         /* Part of a range */
 370                         return -EINVAL;
 371                 child->thread.debug.dbcr2 &= ~(DBCR2_DVC2M | DBCR2_DVC2BE);
 372 #endif
 373 #if CONFIG_PPC_ADV_DEBUG_DVCS > 0
 374                 child->thread.debug.dvc2 = 0;
 375 #endif
 376                 child->thread.debug.dac2 = 0;
 377                 dbcr_dac(child) &= ~(DBCR_DAC2R | DBCR_DAC2W);
 378         } else {
 379                 return -EINVAL;
 380         }
 381
 382         return 0;
 383 }
 384
 385 #ifdef CONFIG_PPC_ADV_DEBUG_DAC_RANGE
 386 static int set_dac_range(struct task_struct *child,
 387                          struct ppc_hw_breakpoint *bp_info)
 388 {
 389         int mode = bp_info->addr_mode & PPC_BREAKPOINT_MODE_MASK;
 390
 391         /* We don't allow range watchpoints to be used with DVC */
 392         if (bp_info->condition_mode)
 393                 return -EINVAL;
 394
 395         /*
 396          * Best effort to verify the address range.  The user/supervisor bits
 397          * prevent trapping in kernel space, but let's fail on an obvious bad
 398          * range.  The simple test on the mask is not fool-proof, and any
 399          * exclusive range will spill over into kernel space.
 400          */
 401         if (bp_info->addr >= TASK_SIZE)
 402                 return -EIO;
 403         if (mode == PPC_BREAKPOINT_MODE_MASK) {
 404                 /*
 405                  * dac2 is a bitmask.  Don't allow a mask that makes a
 406                  * kernel space address from a valid dac1 value
 407                  */
 408                 if (~((unsigned long)bp_info->addr2) >= TASK_SIZE)
 409                         return -EIO;
 410         } else {
 411                 /*
 412                  * For range breakpoints, addr2 must also be a valid address
 413                  */
 414                 if (bp_info->addr2 >= TASK_SIZE)
 415                         return -EIO;
 416         }
 417
 418         if (child->thread.debug.dbcr0 &
 419             (DBCR0_DAC1R | DBCR0_DAC1W | DBCR0_DAC2R | DBCR0_DAC2W))
 420                 return -ENOSPC;
 421
 422         if (bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_READ)
 423                 child->thread.debug.dbcr0 |= (DBCR0_DAC1R | DBCR0_IDM);
 424         if (bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_WRITE)
 425                 child->thread.debug.dbcr0 |= (DBCR0_DAC1W | DBCR0_IDM);
 426         child->thread.debug.dac1 = bp_info->addr;
 427         child->thread.debug.dac2 = bp_info->addr2;
 428         if (mode == PPC_BREAKPOINT_MODE_RANGE_INCLUSIVE)
 429                 child->thread.debug.dbcr2  |= DBCR2_DAC12M;
 430         else if (mode == PPC_BREAKPOINT_MODE_RANGE_EXCLUSIVE)
 431                 child->thread.debug.dbcr2  |= DBCR2_DAC12MX;
 432         else    /* PPC_BREAKPOINT_MODE_MASK */
 433                 child->thread.debug.dbcr2  |= DBCR2_DAC12MM;
 434         regs_set_return_msr(child->thread.regs, child->thread.regs->msr | MSR_DE);
 435
 436         return 5;
 437 }
 438 #endif /* CONFIG_PPC_ADV_DEBUG_DAC_RANGE */
 439
 440 long ppc_set_hwdebug(struct task_struct *child, struct ppc_hw_breakpoint *bp_info)
 441 {
 442         if (bp_info->version != 1)
 443                 return -ENOTSUPP;
 444         /*
 445          * Check for invalid flags and combinations
 446          */
 447         if (bp_info->trigger_type == 0 ||
 448             (bp_info->trigger_type & ~(PPC_BREAKPOINT_TRIGGER_EXECUTE |
 449                                        PPC_BREAKPOINT_TRIGGER_RW)) ||
 450             (bp_info->addr_mode & ~PPC_BREAKPOINT_MODE_MASK) ||
 451             (bp_info->condition_mode &
 452              ~(PPC_BREAKPOINT_CONDITION_MODE |
 453                PPC_BREAKPOINT_CONDITION_BE_ALL)))
 454                 return -EINVAL;
 455 #if CONFIG_PPC_ADV_DEBUG_DVCS == 0
 456         if (bp_info->condition_mode != PPC_BREAKPOINT_CONDITION_NONE)
 457                 return -EINVAL;
 458 #endif
 459
 460         if (bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_EXECUTE) {
 461                 if (bp_info->trigger_type != PPC_BREAKPOINT_TRIGGER_EXECUTE ||
 462                     bp_info->condition_mode != PPC_BREAKPOINT_CONDITION_NONE)
 463                         return -EINVAL;
 464                 return set_instruction_bp(child, bp_info);
 465         }
 466         if (bp_info->addr_mode == PPC_BREAKPOINT_MODE_EXACT)
 467                 return set_dac(child, bp_info);
 468
 469 #ifdef CONFIG_PPC_ADV_DEBUG_DAC_RANGE
 470         return set_dac_range(child, bp_info);
 471 #else
 472         return -EINVAL;
 473 #endif
 474 }
 475
 476 long ppc_del_hwdebug(struct task_struct *child, long data)
 477 {
 478         int rc;
 479
 480         if (data <= 4)
 481                 rc = del_instruction_bp(child, (int)data);
 482         else
 483                 rc = del_dac(child, (int)data - 4);
 484
 485         if (!rc) {
 486                 if (!DBCR_ACTIVE_EVENTS(child->thread.debug.dbcr0,
 487                                         child->thread.debug.dbcr1)) {
 488                         child->thread.debug.dbcr0 &= ~DBCR0_IDM;
 489                         regs_set_return_msr(child->thread.regs,
 490                                         child->thread.regs->msr & ~MSR_DE);
 491                 }
 492         }
 493         return rc;
 494 }