LXR linux/arch/powerpc/kernel/kgdb.c

   1/*
   2 * PowerPC backend to the KGDB stub.
   3 *
   4 * 1998 (c) Michael AK Tesch (tesch@cs.wisc.edu)
   5 * Copyright (C) 2003 Timesys Corporation.
   6 * Copyright (C) 2004-2006 MontaVista Software, Inc.
   7 * PPC64 Mods (C) 2005 Frank Rowand (frowand@mvista.com)
   8 * PPC32 support restored by Vitaly Wool <vwool@ru.mvista.com> and
   9 * Sergei Shtylyov <sshtylyov@ru.mvista.com>
  10 * Copyright (C) 2007-2008 Wind River Systems, Inc.
  11 *
  12 * This file is licensed under the terms of the GNU General Public License
  13 * version 2. This program as licensed "as is" without any warranty of any
  14 * kind, whether express or implied.
  15 */
  16
  17#include <linux/kernel.h>
  18#include <linux/kgdb.h>
  19#include <linux/smp.h>
  20#include <linux/signal.h>
  21#include <linux/ptrace.h>
  22#include <linux/kdebug.h>
  23#include <asm/current.h>
  24#include <asm/processor.h>
  25#include <asm/machdep.h>
  26#include <asm/debug.h>
  27#include <asm/code-patching.h>
  28#include <linux/slab.h>
  29
  30/*
  31 * This table contains the mapping between PowerPC hardware trap types, and
  32 * signals, which are primarily what GDB understands.  GDB and the kernel
  33 * don't always agree on values, so we use constants taken from gdb-6.2.
  34 */
  35static struct hard_trap_info
  36{
  37        unsigned int tt;                /* Trap type code for powerpc */
  38        unsigned char signo;            /* Signal that we map this trap into */
  39} hard_trap_info[] = {
  40        { 0x0100, 0x02 /* SIGINT */  },         /* system reset */
  41        { 0x0200, 0x0b /* SIGSEGV */ },         /* machine check */
  42        { 0x0300, 0x0b /* SIGSEGV */ },         /* data access */
  43        { 0x0400, 0x0b /* SIGSEGV */ },         /* instruction access */
  44        { 0x0500, 0x02 /* SIGINT */  },         /* external interrupt */
  45        { 0x0600, 0x0a /* SIGBUS */  },         /* alignment */
  46        { 0x0700, 0x05 /* SIGTRAP */ },         /* program check */
  47        { 0x0800, 0x08 /* SIGFPE */  },         /* fp unavailable */
  48        { 0x0900, 0x0e /* SIGALRM */ },         /* decrementer */
  49        { 0x0c00, 0x14 /* SIGCHLD */ },         /* system call */
  50#if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
  51        { 0x2002, 0x05 /* SIGTRAP */ },         /* debug */
  52#if defined(CONFIG_FSL_BOOKE)
  53        { 0x2010, 0x08 /* SIGFPE */  },         /* spe unavailable */
  54        { 0x2020, 0x08 /* SIGFPE */  },         /* spe unavailable */
  55        { 0x2030, 0x08 /* SIGFPE */  },         /* spe fp data */
  56        { 0x2040, 0x08 /* SIGFPE */  },         /* spe fp data */
  57        { 0x2050, 0x08 /* SIGFPE */  },         /* spe fp round */
  58        { 0x2060, 0x0e /* SIGILL */  },         /* performance monitor */
  59        { 0x2900, 0x08 /* SIGFPE */  },         /* apu unavailable */
  60        { 0x3100, 0x0e /* SIGALRM */ },         /* fixed interval timer */
  61        { 0x3200, 0x02 /* SIGINT */  },         /* watchdog */
  62#else /* ! CONFIG_FSL_BOOKE */
  63        { 0x1000, 0x0e /* SIGALRM */ },         /* prog interval timer */
  64        { 0x1010, 0x0e /* SIGALRM */ },         /* fixed interval timer */
  65        { 0x1020, 0x02 /* SIGINT */  },         /* watchdog */
  66        { 0x2010, 0x08 /* SIGFPE */  },         /* fp unavailable */
  67        { 0x2020, 0x08 /* SIGFPE */  },         /* ap unavailable */
  68#endif
  69#else /* ! (defined(CONFIG_40x) || defined(CONFIG_BOOKE)) */
  70        { 0x0d00, 0x05 /* SIGTRAP */ },         /* single-step */
  71#if defined(CONFIG_PPC_8xx)
  72        { 0x1000, 0x04 /* SIGILL */  },         /* software emulation */
  73#else /* ! CONFIG_PPC_8xx */
  74        { 0x0f00, 0x04 /* SIGILL */  },         /* performance monitor */
  75        { 0x0f20, 0x08 /* SIGFPE */  },         /* altivec unavailable */
  76        { 0x1300, 0x05 /* SIGTRAP */ },         /* instruction address break */
  77#if defined(CONFIG_PPC64)
  78        { 0x1200, 0x05 /* SIGILL */  },         /* system error */
  79        { 0x1500, 0x04 /* SIGILL */  },         /* soft patch */
  80        { 0x1600, 0x04 /* SIGILL */  },         /* maintenance */
  81        { 0x1700, 0x08 /* SIGFPE */  },         /* altivec assist */
  82        { 0x1800, 0x04 /* SIGILL */  },         /* thermal */
  83#else /* ! CONFIG_PPC64 */
  84        { 0x1400, 0x02 /* SIGINT */  },         /* SMI */
  85        { 0x1600, 0x08 /* SIGFPE */  },         /* altivec assist */
  86        { 0x1700, 0x04 /* SIGILL */  },         /* TAU */
  87        { 0x2000, 0x05 /* SIGTRAP */ },         /* run mode */
  88#endif
  89#endif
  90#endif
  91        { 0x0000, 0x00 }                        /* Must be last */
  92};
  93
  94static int computeSignal(unsigned int tt)
  95{
  96        struct hard_trap_info *ht;
  97
  98        for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
  99                if (ht->tt == tt)
 100                        return ht->signo;
 101
 102        return SIGHUP;          /* default for things we don't know about */
 103}
 104
 105/**
 106 *
 107 *      kgdb_skipexception - Bail out of KGDB when we've been triggered.
 108 *      @exception: Exception vector number
 109 *      @regs: Current &struct pt_regs.
 110 *
 111 *      On some architectures we need to skip a breakpoint exception when
 112 *      it occurs after a breakpoint has been removed.
 113 *
 114 */
 115int kgdb_skipexception(int exception, struct pt_regs *regs)
 116{
 117        return kgdb_isremovedbreak(regs->nip);
 118}
 119
 120static int kgdb_debugger_ipi(struct pt_regs *regs)
 121{
 122        kgdb_nmicallback(raw_smp_processor_id(), regs);
 123        return 0;
 124}
 125
 126#ifdef CONFIG_SMP
 127void kgdb_roundup_cpus(void)
 128{
 129        smp_send_debugger_break();
 130}
 131#endif
 132
 133/* KGDB functions to use existing PowerPC64 hooks. */
 134static int kgdb_debugger(struct pt_regs *regs)
 135{
 136        return !kgdb_handle_exception(1, computeSignal(TRAP(regs)),
 137                                      DIE_OOPS, regs);
 138}
 139
 140static int kgdb_handle_breakpoint(struct pt_regs *regs)
 141{
 142        if (user_mode(regs))
 143                return 0;
 144
 145        if (kgdb_handle_exception(1, SIGTRAP, 0, regs) != 0)
 146                return 0;
 147
 148        if (*(u32 *)regs->nip == BREAK_INSTR)
 149                regs->nip += BREAK_INSTR_SIZE;
 150
 151        return 1;
 152}
 153
 154static int kgdb_singlestep(struct pt_regs *regs)
 155{
 156        if (user_mode(regs))
 157                return 0;
 158
 159        kgdb_handle_exception(0, SIGTRAP, 0, regs);
 160
 161        return 1;
 162}
 163
 164static int kgdb_iabr_match(struct pt_regs *regs)
 165{
 166        if (user_mode(regs))
 167                return 0;
 168
 169        if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0)
 170                return 0;
 171        return 1;
 172}
 173
 174static int kgdb_break_match(struct pt_regs *regs)
 175{
 176        if (user_mode(regs))
 177                return 0;
 178
 179        if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0)
 180                return 0;
 181        return 1;
 182}
 183
 184#define PACK64(ptr, src) do { *(ptr++) = (src); } while (0)
 185
 186#define PACK32(ptr, src) do {          \
 187        u32 *ptr32;                   \
 188        ptr32 = (u32 *)ptr;           \
 189        *(ptr32++) = (src);           \
 190        ptr = (unsigned long *)ptr32; \
 191        } while (0)
 192
 193void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
 194{
 195        struct pt_regs *regs = (struct pt_regs *)(p->thread.ksp +
 196                                                  STACK_FRAME_OVERHEAD);
 197        unsigned long *ptr = gdb_regs;
 198        int reg;
 199
 200        memset(gdb_regs, 0, NUMREGBYTES);
 201
 202        /* Regs GPR0-2 */
 203        for (reg = 0; reg < 3; reg++)
 204                PACK64(ptr, regs->gpr[reg]);
 205
 206        /* Regs GPR3-13 are caller saved, not in regs->gpr[] */
 207        ptr += 11;
 208
 209        /* Regs GPR14-31 */
 210        for (reg = 14; reg < 32; reg++)
 211                PACK64(ptr, regs->gpr[reg]);
 212
 213#ifdef CONFIG_FSL_BOOKE
 214#ifdef CONFIG_SPE
 215        for (reg = 0; reg < 32; reg++)
 216                PACK64(ptr, p->thread.evr[reg]);
 217#else
 218        ptr += 32;
 219#endif
 220#else
 221        /* fp registers not used by kernel, leave zero */
 222        ptr += 32 * 8 / sizeof(long);
 223#endif
 224
 225        PACK64(ptr, regs->nip);
 226        PACK64(ptr, regs->msr);
 227        PACK32(ptr, regs->ccr);
 228        PACK64(ptr, regs->link);
 229        PACK64(ptr, regs->ctr);
 230        PACK32(ptr, regs->xer);
 231
 232        BUG_ON((unsigned long)ptr >
 233               (unsigned long)(((void *)gdb_regs) + NUMREGBYTES));
 234}
 235
 236#define GDB_SIZEOF_REG sizeof(unsigned long)
 237#define GDB_SIZEOF_REG_U32 sizeof(u32)
 238
 239#ifdef CONFIG_FSL_BOOKE
 240#define GDB_SIZEOF_FLOAT_REG sizeof(unsigned long)
 241#else
 242#define GDB_SIZEOF_FLOAT_REG sizeof(u64)
 243#endif
 244
 245struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
 246{
 247        { "r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[0]) },
 248        { "r1", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[1]) },
 249        { "r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[2]) },
 250        { "r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[3]) },
 251        { "r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[4]) },
 252        { "r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[5]) },
 253        { "r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[6]) },
 254        { "r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[7]) },
 255        { "r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[8]) },
 256        { "r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[9]) },
 257        { "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[10]) },
 258        { "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[11]) },
 259        { "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[12]) },
 260        { "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[13]) },
 261        { "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[14]) },
 262        { "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[15]) },
 263        { "r16", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[16]) },
 264        { "r17", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[17]) },
 265        { "r18", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[18]) },
 266        { "r19", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[19]) },
 267        { "r20", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[20]) },
 268        { "r21", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[21]) },
 269        { "r22", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[22]) },
 270        { "r23", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[23]) },
 271        { "r24", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[24]) },
 272        { "r25", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[25]) },
 273        { "r26", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[26]) },
 274        { "r27", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[27]) },
 275        { "r28", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[28]) },
 276        { "r29", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[29]) },
 277        { "r30", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[30]) },
 278        { "r31", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[31]) },
 279
 280        { "f0", GDB_SIZEOF_FLOAT_REG, 0 },
 281        { "f1", GDB_SIZEOF_FLOAT_REG, 1 },
 282        { "f2", GDB_SIZEOF_FLOAT_REG, 2 },
 283        { "f3", GDB_SIZEOF_FLOAT_REG, 3 },
 284        { "f4", GDB_SIZEOF_FLOAT_REG, 4 },
 285        { "f5", GDB_SIZEOF_FLOAT_REG, 5 },
 286        { "f6", GDB_SIZEOF_FLOAT_REG, 6 },
 287        { "f7", GDB_SIZEOF_FLOAT_REG, 7 },
 288        { "f8", GDB_SIZEOF_FLOAT_REG, 8 },
 289        { "f9", GDB_SIZEOF_FLOAT_REG, 9 },
 290        { "f10", GDB_SIZEOF_FLOAT_REG, 10 },
 291        { "f11", GDB_SIZEOF_FLOAT_REG, 11 },
 292        { "f12", GDB_SIZEOF_FLOAT_REG, 12 },
 293        { "f13", GDB_SIZEOF_FLOAT_REG, 13 },
 294        { "f14", GDB_SIZEOF_FLOAT_REG, 14 },
 295        { "f15", GDB_SIZEOF_FLOAT_REG, 15 },
 296        { "f16", GDB_SIZEOF_FLOAT_REG, 16 },
 297        { "f17", GDB_SIZEOF_FLOAT_REG, 17 },
 298        { "f18", GDB_SIZEOF_FLOAT_REG, 18 },
 299        { "f19", GDB_SIZEOF_FLOAT_REG, 19 },
 300        { "f20", GDB_SIZEOF_FLOAT_REG, 20 },
 301        { "f21", GDB_SIZEOF_FLOAT_REG, 21 },
 302        { "f22", GDB_SIZEOF_FLOAT_REG, 22 },
 303        { "f23", GDB_SIZEOF_FLOAT_REG, 23 },
 304        { "f24", GDB_SIZEOF_FLOAT_REG, 24 },
 305        { "f25", GDB_SIZEOF_FLOAT_REG, 25 },
 306        { "f26", GDB_SIZEOF_FLOAT_REG, 26 },
 307        { "f27", GDB_SIZEOF_FLOAT_REG, 27 },
 308        { "f28", GDB_SIZEOF_FLOAT_REG, 28 },
 309        { "f29", GDB_SIZEOF_FLOAT_REG, 29 },
 310        { "f30", GDB_SIZEOF_FLOAT_REG, 30 },
 311        { "f31", GDB_SIZEOF_FLOAT_REG, 31 },
 312
 313        { "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, nip) },
 314        { "msr", GDB_SIZEOF_REG, offsetof(struct pt_regs, msr) },
 315        { "cr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ccr) },
 316        { "lr", GDB_SIZEOF_REG, offsetof(struct pt_regs, link) },
 317        { "ctr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ctr) },
 318        { "xer", GDB_SIZEOF_REG, offsetof(struct pt_regs, xer) },
 319};
 320
 321char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
 322{
 323        if (regno >= DBG_MAX_REG_NUM || regno < 0)
 324                return NULL;
 325
 326        if (regno < 32 || regno >= 64)
 327                /* First 0 -> 31 gpr registers*/
 328                /* pc, msr, ls... registers 64 -> 69 */
 329                memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
 330                                dbg_reg_def[regno].size);
 331
 332        if (regno >= 32 && regno < 64) {
 333                /* FP registers 32 -> 63 */
 334#if defined(CONFIG_FSL_BOOKE) && defined(CONFIG_SPE)
 335                if (current)
 336                        memcpy(mem, &current->thread.evr[regno-32],
 337                                        dbg_reg_def[regno].size);
 338#else
 339                /* fp registers not used by kernel, leave zero */
 340                memset(mem, 0, dbg_reg_def[regno].size);
 341#endif
 342        }
 343
 344        return dbg_reg_def[regno].name;
 345}
 346
 347int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
 348{
 349        if (regno >= DBG_MAX_REG_NUM || regno < 0)
 350                return -EINVAL;
 351
 352        if (regno < 32 || regno >= 64)
 353                /* First 0 -> 31 gpr registers*/
 354                /* pc, msr, ls... registers 64 -> 69 */
 355                memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
 356                                dbg_reg_def[regno].size);
 357
 358        if (regno >= 32 && regno < 64) {
 359                /* FP registers 32 -> 63 */
 360#if defined(CONFIG_FSL_BOOKE) && defined(CONFIG_SPE)
 361                memcpy(&current->thread.evr[regno-32], mem,
 362                                dbg_reg_def[regno].size);
 363#else
 364                /* fp registers not used by kernel, leave zero */
 365                return 0;
 366#endif
 367        }
 368
 369        return 0;
 370}
 371
 372void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
 373{
 374        regs->nip = pc;
 375}
 376
 377/*
 378 * This function does PowerPC specific procesing for interfacing to gdb.
 379 */
 380int kgdb_arch_handle_exception(int vector, int signo, int err_code,
 381                               char *remcom_in_buffer, char *remcom_out_buffer,
 382                               struct pt_regs *linux_regs)
 383{
 384        char *ptr = &remcom_in_buffer[1];
 385        unsigned long addr;
 386
 387        switch (remcom_in_buffer[0]) {
 388                /*
 389                 * sAA..AA   Step one instruction from AA..AA
 390                 * This will return an error to gdb ..
 391                 */
 392        case 's':
 393        case 'c':
 394                /* handle the optional parameter */
 395                if (kgdb_hex2long(&ptr, &addr))
 396                        linux_regs->nip = addr;
 397
 398                atomic_set(&kgdb_cpu_doing_single_step, -1);
 399                /* set the trace bit if we're stepping */
 400                if (remcom_in_buffer[0] == 's') {
 401#ifdef CONFIG_PPC_ADV_DEBUG_REGS
 402                        mtspr(SPRN_DBCR0,
 403                              mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM);
 404                        linux_regs->msr |= MSR_DE;
 405#else
 406                        linux_regs->msr |= MSR_SE;
 407#endif
 408                        atomic_set(&kgdb_cpu_doing_single_step,
 409                                   raw_smp_processor_id());
 410                }
 411                return 0;
 412        }
 413
 414        return -1;
 415}
 416
 417int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
 418{
 419        int err;
 420        unsigned int instr;
 421        unsigned int *addr = (unsigned int *)bpt->bpt_addr;
 422
 423        err = probe_kernel_address(addr, instr);
 424        if (err)
 425                return err;
 426
 427        err = patch_instruction(addr, BREAK_INSTR);
 428        if (err)
 429                return -EFAULT;
 430
 431        *(unsigned int *)bpt->saved_instr = instr;
 432
 433        return 0;
 434}
 435
 436int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
 437{
 438        int err;
 439        unsigned int instr = *(unsigned int *)bpt->saved_instr;
 440        unsigned int *addr = (unsigned int *)bpt->bpt_addr;
 441
 442        err = patch_instruction(addr, instr);
 443        if (err)
 444                return -EFAULT;
 445
 446        return 0;
 447}
 448
 449/*
 450 * Global data
 451 */
 452const struct kgdb_arch arch_kgdb_ops;
 453
 454static int kgdb_not_implemented(struct pt_regs *regs)
 455{
 456        return 0;
 457}
 458
 459static void *old__debugger_ipi;
 460static void *old__debugger;
 461static void *old__debugger_bpt;
 462static void *old__debugger_sstep;
 463static void *old__debugger_iabr_match;
 464static void *old__debugger_break_match;
 465static void *old__debugger_fault_handler;
 466
 467int kgdb_arch_init(void)
 468{
 469        old__debugger_ipi = __debugger_ipi;
 470        old__debugger = __debugger;
 471        old__debugger_bpt = __debugger_bpt;
 472        old__debugger_sstep = __debugger_sstep;
 473        old__debugger_iabr_match = __debugger_iabr_match;
 474        old__debugger_break_match = __debugger_break_match;
 475        old__debugger_fault_handler = __debugger_fault_handler;
 476
 477        __debugger_ipi = kgdb_debugger_ipi;
 478        __debugger = kgdb_debugger;
 479        __debugger_bpt = kgdb_handle_breakpoint;
 480        __debugger_sstep = kgdb_singlestep;
 481        __debugger_iabr_match = kgdb_iabr_match;
 482        __debugger_break_match = kgdb_break_match;
 483        __debugger_fault_handler = kgdb_not_implemented;
 484
 485        return 0;
 486}
 487
 488void kgdb_arch_exit(void)
 489{
 490        __debugger_ipi = old__debugger_ipi;
 491        __debugger = old__debugger;
 492        __debugger_bpt = old__debugger_bpt;
 493        __debugger_sstep = old__debugger_sstep;
 494        __debugger_iabr_match = old__debugger_iabr_match;
 495        __debugger_break_match = old__debugger_break_match;
 496        __debugger_fault_handler = old__debugger_fault_handler;
 497}
 498