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/init.h>
  19 #include <linux/kgdb.h>
  20 #include <linux/smp.h>
  21 #include <linux/signal.h>
  22 #include <linux/ptrace.h>
  23 #include <linux/kdebug.h>
  24 #include <asm/current.h>
  25 #include <asm/processor.h>
  26 #include <asm/machdep.h>
  27
  28 /*
  29  * This table contains the mapping between PowerPC hardware trap types, and
  30  * signals, which are primarily what GDB understands.  GDB and the kernel
  31  * don't always agree on values, so we use constants taken from gdb-6.2.
  32  */
  33 static struct hard_trap_info
  34 {
  35         unsigned int tt;                /* Trap type code for powerpc */
  36         unsigned char signo;            /* Signal that we map this trap into */
  37 } hard_trap_info[] = {
  38         { 0x0100, 0x02 /* SIGINT */  },         /* system reset */
  39         { 0x0200, 0x0b /* SIGSEGV */ },         /* machine check */
  40         { 0x0300, 0x0b /* SIGSEGV */ },         /* data access */
  41         { 0x0400, 0x0b /* SIGSEGV */ },         /* instruction access */
  42         { 0x0500, 0x02 /* SIGINT */  },         /* external interrupt */
  43         { 0x0600, 0x0a /* SIGBUS */  },         /* alignment */
  44         { 0x0700, 0x05 /* SIGTRAP */ },         /* program check */
  45         { 0x0800, 0x08 /* SIGFPE */  },         /* fp unavailable */
  46         { 0x0900, 0x0e /* SIGALRM */ },         /* decrementer */
  47         { 0x0c00, 0x14 /* SIGCHLD */ },         /* system call */
  48 #if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
  49         { 0x2002, 0x05 /* SIGTRAP */ },         /* debug */
  50 #if defined(CONFIG_FSL_BOOKE)
  51         { 0x2010, 0x08 /* SIGFPE */  },         /* spe unavailable */
  52         { 0x2020, 0x08 /* SIGFPE */  },         /* spe unavailable */
  53         { 0x2030, 0x08 /* SIGFPE */  },         /* spe fp data */
  54         { 0x2040, 0x08 /* SIGFPE */  },         /* spe fp data */
  55         { 0x2050, 0x08 /* SIGFPE */  },         /* spe fp round */
  56         { 0x2060, 0x0e /* SIGILL */  },         /* performance monitor */
  57         { 0x2900, 0x08 /* SIGFPE */  },         /* apu unavailable */
  58         { 0x3100, 0x0e /* SIGALRM */ },         /* fixed interval timer */
  59         { 0x3200, 0x02 /* SIGINT */  },         /* watchdog */
  60 #else /* ! CONFIG_FSL_BOOKE */
  61         { 0x1000, 0x0e /* SIGALRM */ },         /* prog interval timer */
  62         { 0x1010, 0x0e /* SIGALRM */ },         /* fixed interval timer */
  63         { 0x1020, 0x02 /* SIGINT */  },         /* watchdog */
  64         { 0x2010, 0x08 /* SIGFPE */  },         /* fp unavailable */
  65         { 0x2020, 0x08 /* SIGFPE */  },         /* ap unavailable */
  66 #endif
  67 #else /* ! (defined(CONFIG_40x) || defined(CONFIG_BOOKE)) */
  68         { 0x0d00, 0x05 /* SIGTRAP */ },         /* single-step */
  69 #if defined(CONFIG_8xx)
  70         { 0x1000, 0x04 /* SIGILL */  },         /* software emulation */
  71 #else /* ! CONFIG_8xx */
  72         { 0x0f00, 0x04 /* SIGILL */  },         /* performance monitor */
  73         { 0x0f20, 0x08 /* SIGFPE */  },         /* altivec unavailable */
  74         { 0x1300, 0x05 /* SIGTRAP */ },         /* instruction address break */
  75 #if defined(CONFIG_PPC64)
  76         { 0x1200, 0x05 /* SIGILL */  },         /* system error */
  77         { 0x1500, 0x04 /* SIGILL */  },         /* soft patch */
  78         { 0x1600, 0x04 /* SIGILL */  },         /* maintenance */
  79         { 0x1700, 0x08 /* SIGFPE */  },         /* altivec assist */
  80         { 0x1800, 0x04 /* SIGILL */  },         /* thermal */
  81 #else /* ! CONFIG_PPC64 */
  82         { 0x1400, 0x02 /* SIGINT */  },         /* SMI */
  83         { 0x1600, 0x08 /* SIGFPE */  },         /* altivec assist */
  84         { 0x1700, 0x04 /* SIGILL */  },         /* TAU */
  85         { 0x2000, 0x05 /* SIGTRAP */ },         /* run mode */
  86 #endif
  87 #endif
  88 #endif
  89         { 0x0000, 0x00 }                        /* Must be last */
  90 };
  91
  92 static int computeSignal(unsigned int tt)
  93 {
  94         struct hard_trap_info *ht;
  95
  96         for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
  97                 if (ht->tt == tt)
  98                         return ht->signo;
  99
 100         return SIGHUP;          /* default for things we don't know about */
 101 }
 102
 103 static int kgdb_call_nmi_hook(struct pt_regs *regs)
 104 {
 105         kgdb_nmicallback(raw_smp_processor_id(), regs);
 106         return 0;
 107 }
 108
 109 #ifdef CONFIG_SMP
 110 void kgdb_roundup_cpus(unsigned long flags)
 111 {
 112         smp_send_debugger_break(MSG_ALL_BUT_SELF);
 113 }
 114 #endif
 115
 116 /* KGDB functions to use existing PowerPC64 hooks. */
 117 static int kgdb_debugger(struct pt_regs *regs)
 118 {
 119         return !kgdb_handle_exception(1, computeSignal(TRAP(regs)),
 120                                       DIE_OOPS, regs);
 121 }
 122
 123 static int kgdb_handle_breakpoint(struct pt_regs *regs)
 124 {
 125         if (user_mode(regs))
 126                 return 0;
 127
 128         if (kgdb_handle_exception(1, SIGTRAP, 0, regs) != 0)
 129                 return 0;
 130
 131         if (*(u32 *) (regs->nip) == *(u32 *) (&arch_kgdb_ops.gdb_bpt_instr))
 132                 regs->nip += BREAK_INSTR_SIZE;
 133
 134         return 1;
 135 }
 136
 137 static int kgdb_singlestep(struct pt_regs *regs)
 138 {
 139         struct thread_info *thread_info, *exception_thread_info;
 140
 141         if (user_mode(regs))
 142                 return 0;
 143
 144         /*
 145          * On Book E and perhaps other processsors, singlestep is handled on
 146          * the critical exception stack.  This causes current_thread_info()
 147          * to fail, since it it locates the thread_info by masking off
 148          * the low bits of the current stack pointer.  We work around
 149          * this issue by copying the thread_info from the kernel stack
 150          * before calling kgdb_handle_exception, and copying it back
 151          * afterwards.  On most processors the copy is avoided since
 152          * exception_thread_info == thread_info.
 153          */
 154         thread_info = (struct thread_info *)(regs->gpr[1] & ~(THREAD_SIZE-1));
 155         exception_thread_info = current_thread_info();
 156
 157         if (thread_info != exception_thread_info)
 158                 memcpy(exception_thread_info, thread_info, sizeof *thread_info);
 159
 160         kgdb_handle_exception(0, SIGTRAP, 0, regs);
 161
 162         if (thread_info != exception_thread_info)
 163                 memcpy(thread_info, exception_thread_info, sizeof *thread_info);
 164
 165         return 1;
 166 }
 167
 168 static int kgdb_iabr_match(struct pt_regs *regs)
 169 {
 170         if (user_mode(regs))
 171                 return 0;
 172
 173         if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0)
 174                 return 0;
 175         return 1;
 176 }
 177
 178 static int kgdb_dabr_match(struct pt_regs *regs)
 179 {
 180         if (user_mode(regs))
 181                 return 0;
 182
 183         if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0)
 184                 return 0;
 185         return 1;
 186 }
 187
 188 #define PACK64(ptr, src) do { *(ptr++) = (src); } while (0)
 189
 190 #define PACK32(ptr, src) do {          \
 191         u32 *ptr32;                   \
 192         ptr32 = (u32 *)ptr;           \
 193         *(ptr32++) = (src);           \
 194         ptr = (unsigned long *)ptr32; \
 195         } while (0)
 196
 197 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
 198 {
 199         struct pt_regs *regs = (struct pt_regs *)(p->thread.ksp +
 200                                                   STACK_FRAME_OVERHEAD);
 201         unsigned long *ptr = gdb_regs;
 202         int reg;
 203
 204         memset(gdb_regs, 0, NUMREGBYTES);
 205
 206         /* Regs GPR0-2 */
 207         for (reg = 0; reg < 3; reg++)
 208                 PACK64(ptr, regs->gpr[reg]);
 209
 210         /* Regs GPR3-13 are caller saved, not in regs->gpr[] */
 211         ptr += 11;
 212
 213         /* Regs GPR14-31 */
 214         for (reg = 14; reg < 32; reg++)
 215                 PACK64(ptr, regs->gpr[reg]);
 216
 217 #ifdef CONFIG_FSL_BOOKE
 218 #ifdef CONFIG_SPE
 219         for (reg = 0; reg < 32; reg++)
 220                 PACK64(ptr, p->thread.evr[reg]);
 221 #else
 222         ptr += 32;
 223 #endif
 224 #else
 225         /* fp registers not used by kernel, leave zero */
 226         ptr += 32 * 8 / sizeof(long);
 227 #endif
 228
 229         PACK64(ptr, regs->nip);
 230         PACK64(ptr, regs->msr);
 231         PACK32(ptr, regs->ccr);
 232         PACK64(ptr, regs->link);
 233         PACK64(ptr, regs->ctr);
 234         PACK32(ptr, regs->xer);
 235
 236         BUG_ON((unsigned long)ptr >
 237                (unsigned long)(((void *)gdb_regs) + NUMREGBYTES));
 238 }
 239
 240 #define GDB_SIZEOF_REG sizeof(unsigned long)
 241 #define GDB_SIZEOF_REG_U32 sizeof(u32)
 242
 243 #ifdef CONFIG_FSL_BOOKE
 244 #define GDB_SIZEOF_FLOAT_REG sizeof(unsigned long)
 245 #else
 246 #define GDB_SIZEOF_FLOAT_REG sizeof(u64)
 247 #endif
 248
 249 struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
 250 {
 251         { "r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[0]) },
 252         { "r1", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[1]) },
 253         { "r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[2]) },
 254         { "r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[3]) },
 255         { "r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[4]) },
 256         { "r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[5]) },
 257         { "r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[6]) },
 258         { "r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[7]) },
 259         { "r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[8]) },
 260         { "r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[9]) },
 261         { "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[10]) },
 262         { "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[11]) },
 263         { "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[12]) },
 264         { "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[13]) },
 265         { "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[14]) },
 266         { "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[15]) },
 267         { "r16", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[16]) },
 268         { "r17", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[17]) },
 269         { "r18", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[18]) },
 270         { "r19", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[19]) },
 271         { "r20", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[20]) },
 272         { "r21", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[21]) },
 273         { "r22", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[22]) },
 274         { "r23", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[23]) },
 275         { "r24", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[24]) },
 276         { "r25", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[25]) },
 277         { "r26", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[26]) },
 278         { "r27", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[27]) },
 279         { "r28", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[28]) },
 280         { "r29", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[29]) },
 281         { "r30", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[30]) },
 282         { "r31", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[31]) },
 283
 284         { "f0", GDB_SIZEOF_FLOAT_REG, 0 },
 285         { "f1", GDB_SIZEOF_FLOAT_REG, 1 },
 286         { "f2", GDB_SIZEOF_FLOAT_REG, 2 },
 287         { "f3", GDB_SIZEOF_FLOAT_REG, 3 },
 288         { "f4", GDB_SIZEOF_FLOAT_REG, 4 },
 289         { "f5", GDB_SIZEOF_FLOAT_REG, 5 },
 290         { "f6", GDB_SIZEOF_FLOAT_REG, 6 },
 291         { "f7", GDB_SIZEOF_FLOAT_REG, 7 },
 292         { "f8", GDB_SIZEOF_FLOAT_REG, 8 },
 293         { "f9", GDB_SIZEOF_FLOAT_REG, 9 },
 294         { "f10", GDB_SIZEOF_FLOAT_REG, 10 },
 295         { "f11", GDB_SIZEOF_FLOAT_REG, 11 },
 296         { "f12", GDB_SIZEOF_FLOAT_REG, 12 },
 297         { "f13", GDB_SIZEOF_FLOAT_REG, 13 },
 298         { "f14", GDB_SIZEOF_FLOAT_REG, 14 },
 299         { "f15", GDB_SIZEOF_FLOAT_REG, 15 },
 300         { "f16", GDB_SIZEOF_FLOAT_REG, 16 },
 301         { "f17", GDB_SIZEOF_FLOAT_REG, 17 },
 302         { "f18", GDB_SIZEOF_FLOAT_REG, 18 },
 303         { "f19", GDB_SIZEOF_FLOAT_REG, 19 },
 304         { "f20", GDB_SIZEOF_FLOAT_REG, 20 },
 305         { "f21", GDB_SIZEOF_FLOAT_REG, 21 },
 306         { "f22", GDB_SIZEOF_FLOAT_REG, 22 },
 307         { "f23", GDB_SIZEOF_FLOAT_REG, 23 },
 308         { "f24", GDB_SIZEOF_FLOAT_REG, 24 },
 309         { "f25", GDB_SIZEOF_FLOAT_REG, 25 },
 310         { "f26", GDB_SIZEOF_FLOAT_REG, 26 },
 311         { "f27", GDB_SIZEOF_FLOAT_REG, 27 },
 312         { "f28", GDB_SIZEOF_FLOAT_REG, 28 },
 313         { "f29", GDB_SIZEOF_FLOAT_REG, 29 },
 314         { "f30", GDB_SIZEOF_FLOAT_REG, 30 },
 315         { "f31", GDB_SIZEOF_FLOAT_REG, 31 },
 316
 317         { "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, nip) },
 318         { "msr", GDB_SIZEOF_REG, offsetof(struct pt_regs, msr) },
 319         { "cr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ccr) },
 320         { "lr", GDB_SIZEOF_REG, offsetof(struct pt_regs, link) },
 321         { "ctr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ctr) },
 322         { "xer", GDB_SIZEOF_REG, offsetof(struct pt_regs, xer) },
 323 };
 324
 325 char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
 326 {
 327         if (regno >= DBG_MAX_REG_NUM || regno < 0)
 328                 return NULL;
 329
 330         if (regno < 32 || regno >= 64)
 331                 /* First 0 -> 31 gpr registers*/
 332                 /* pc, msr, ls... registers 64 -> 69 */
 333                 memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
 334                                 dbg_reg_def[regno].size);
 335
 336         if (regno >= 32 && regno < 64) {
 337                 /* FP registers 32 -> 63 */
 338 #if defined(CONFIG_FSL_BOOKE) && defined(CONFIG_SPE)
 339                 if (current)
 340                         memcpy(mem, &current->thread.evr[regno-32],
 341                                         dbg_reg_def[regno].size);
 342 #else
 343                 /* fp registers not used by kernel, leave zero */
 344                 memset(mem, 0, dbg_reg_def[regno].size);
 345 #endif
 346         }
 347
 348         return dbg_reg_def[regno].name;
 349 }
 350
 351 int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
 352 {
 353         if (regno >= DBG_MAX_REG_NUM || regno < 0)
 354                 return -EINVAL;
 355
 356         if (regno < 32 || regno >= 64)
 357                 /* First 0 -> 31 gpr registers*/
 358                 /* pc, msr, ls... registers 64 -> 69 */
 359                 memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
 360                                 dbg_reg_def[regno].size);
 361
 362         if (regno >= 32 && regno < 64) {
 363                 /* FP registers 32 -> 63 */
 364 #if defined(CONFIG_FSL_BOOKE) && defined(CONFIG_SPE)
 365                 memcpy(&current->thread.evr[regno-32], mem,
 366                                 dbg_reg_def[regno].size);
 367 #else
 368                 /* fp registers not used by kernel, leave zero */
 369                 return 0;
 370 #endif
 371         }
 372
 373         return 0;
 374 }
 375
 376 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
 377 {
 378         regs->nip = pc;
 379 }
 380
 381 /*
 382  * This function does PowerPC specific procesing for interfacing to gdb.
 383  */
 384 int kgdb_arch_handle_exception(int vector, int signo, int err_code,
 385                                char *remcom_in_buffer, char *remcom_out_buffer,
 386                                struct pt_regs *linux_regs)
 387 {
 388         char *ptr = &remcom_in_buffer[1];
 389         unsigned long addr;
 390
 391         switch (remcom_in_buffer[0]) {
 392                 /*
 393                  * sAA..AA   Step one instruction from AA..AA
 394                  * This will return an error to gdb ..
 395                  */
 396         case 's':
 397         case 'c':
 398                 /* handle the optional parameter */
 399                 if (kgdb_hex2long(&ptr, &addr))
 400                         linux_regs->nip = addr;
 401
 402                 atomic_set(&kgdb_cpu_doing_single_step, -1);
 403                 /* set the trace bit if we're stepping */
 404                 if (remcom_in_buffer[0] == 's') {
 405 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
 406                         mtspr(SPRN_DBCR0,
 407                               mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM);
 408                         linux_regs->msr |= MSR_DE;
 409 #else
 410                         linux_regs->msr |= MSR_SE;
 411 #endif
 412                         kgdb_single_step = 1;
 413                         atomic_set(&kgdb_cpu_doing_single_step,
 414                                    raw_smp_processor_id());
 415                 }
 416                 return 0;
 417         }
 418
 419         return -1;
 420 }
 421
 422 /*
 423  * Global data
 424  */
 425 struct kgdb_arch arch_kgdb_ops = {
 426         .gdb_bpt_instr = {0x7d, 0x82, 0x10, 0x08},
 427 };
 428
 429 static int kgdb_not_implemented(struct pt_regs *regs)
 430 {
 431         return 0;
 432 }
 433
 434 static void *old__debugger_ipi;
 435 static void *old__debugger;
 436 static void *old__debugger_bpt;
 437 static void *old__debugger_sstep;
 438 static void *old__debugger_iabr_match;
 439 static void *old__debugger_dabr_match;
 440 static void *old__debugger_fault_handler;
 441
 442 int kgdb_arch_init(void)
 443 {
 444         old__debugger_ipi = __debugger_ipi;
 445         old__debugger = __debugger;
 446         old__debugger_bpt = __debugger_bpt;
 447         old__debugger_sstep = __debugger_sstep;
 448         old__debugger_iabr_match = __debugger_iabr_match;
 449         old__debugger_dabr_match = __debugger_dabr_match;
 450         old__debugger_fault_handler = __debugger_fault_handler;
 451
 452         __debugger_ipi = kgdb_call_nmi_hook;
 453         __debugger = kgdb_debugger;
 454         __debugger_bpt = kgdb_handle_breakpoint;
 455         __debugger_sstep = kgdb_singlestep;
 456         __debugger_iabr_match = kgdb_iabr_match;
 457         __debugger_dabr_match = kgdb_dabr_match;
 458         __debugger_fault_handler = kgdb_not_implemented;
 459
 460         return 0;
 461 }
 462
 463 void kgdb_arch_exit(void)
 464 {
 465         __debugger_ipi = old__debugger_ipi;
 466         __debugger = old__debugger;
 467         __debugger_bpt = old__debugger_bpt;
 468         __debugger_sstep = old__debugger_sstep;
 469         __debugger_iabr_match = old__debugger_iabr_match;
 470         __debugger_dabr_match = old__debugger_dabr_match;
 471         __debugger_fault_handler = old__debugger_fault_handler;
 472 }