arch/ppc/lib/kgdb.c

   1 #include <common.h>
   2 #include <command.h>
   3 #include <kgdb.h>
   4 #include <asm/signal.h>
   5 #include <asm/processor.h>
   6
   7 #define PC_REGNUM 64
   8 #define SP_REGNUM 1
   9
  10 void breakinst(void);
  11
  12 int
  13 kgdb_setjmp(long *buf)
  14 {
  15         asm ("mflr 0; stw 0,0(%0);"
  16              "stw 1,4(%0); stw 2,8(%0);"
  17              "mfcr 0; stw 0,12(%0);"
  18              "stmw 13,16(%0)"
  19              : : "r" (buf));
  20         /* XXX should save fp regs as well */
  21         return 0;
  22 }
  23
  24 void
  25 kgdb_longjmp(long *buf, int val)
  26 {
  27         if (val == 0)
  28                 val = 1;
  29         asm ("lmw 13,16(%0);"
  30              "lwz 0,12(%0); mtcrf 0x38,0;"
  31              "lwz 0,0(%0); lwz 1,4(%0); lwz 2,8(%0);"
  32              "mtlr 0; mr 3,%1"
  33              : : "r" (buf), "r" (val));
  34 }
  35
  36 static inline unsigned long
  37 get_msr(void)
  38 {
  39         unsigned long msr;
  40         asm volatile("mfmsr %0" : "=r" (msr):);
  41         return msr;
  42 }
  43
  44 static inline void
  45 set_msr(unsigned long msr)
  46 {
  47         asm volatile("mtmsr %0" : : "r" (msr));
  48 }
  49
  50 /* Convert the SPARC hardware trap type code to a unix signal number. */
  51 /*
  52  * This table contains the mapping between PowerPC hardware trap types, and
  53  * signals, which are primarily what GDB understands.
  54  */
  55 static struct hard_trap_info
  56 {
  57         unsigned int tt;                /* Trap type code for powerpc */
  58         unsigned char signo;            /* Signal that we map this trap into */
  59 } hard_trap_info[] = {
  60         { 0x200, SIGSEGV },                     /* machine check */
  61         { 0x300, SIGSEGV },                     /* address error (store) */
  62         { 0x400, SIGBUS },                      /* instruction bus error */
  63         { 0x500, SIGINT },                      /* interrupt */
  64         { 0x600, SIGBUS },                      /* alingment */
  65         { 0x700, SIGTRAP },                     /* breakpoint trap */
  66         { 0x800, SIGFPE },                      /* fpu unavail */
  67         { 0x900, SIGALRM },                     /* decrementer */
  68         { 0xa00, SIGILL },                      /* reserved */
  69         { 0xb00, SIGILL },                      /* reserved */
  70         { 0xc00, SIGCHLD },                     /* syscall */
  71         { 0xd00, SIGTRAP },                     /* single-step/watch */
  72         { 0xe00, SIGFPE },                      /* fp assist */
  73         { 0, 0}                         /* Must be last */
  74 };
  75
  76 static int
  77 computeSignal(unsigned int tt)
  78 {
  79         struct hard_trap_info *ht;
  80
  81         for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
  82                 if (ht->tt == tt)
  83                         return ht->signo;
  84
  85         return SIGHUP;         /* default for things we don't know about */
  86 }
  87
  88 void
  89 kgdb_enter(struct pt_regs *regs, kgdb_data *kdp)
  90 {
  91         unsigned long msr;
  92
  93         kdp->private[0] = msr = get_msr();
  94         set_msr(msr & ~MSR_EE); /* disable interrupts */
  95
  96         if (regs->nip == (unsigned long)breakinst) {
  97                 /* Skip over breakpoint trap insn */
  98                 regs->nip += 4;
  99         }
 100         regs->msr &= ~MSR_SE;
 101
 102         /* reply to host that an exception has occurred */
 103         kdp->sigval = computeSignal(regs->trap);
 104
 105         kdp->nregs = 2;
 106
 107         kdp->regs[0].num = PC_REGNUM;
 108         kdp->regs[0].val = regs->nip;
 109
 110         kdp->regs[1].num = SP_REGNUM;
 111         kdp->regs[1].val = regs->gpr[SP_REGNUM];
 112 }
 113
 114 void
 115 kgdb_exit(struct pt_regs *regs, kgdb_data *kdp)
 116 {
 117         unsigned long msr = kdp->private[0];
 118
 119         if (kdp->extype & KGDBEXIT_WITHADDR)
 120                 regs->nip = kdp->exaddr;
 121
 122         switch (kdp->extype & KGDBEXIT_TYPEMASK) {
 123
 124         case KGDBEXIT_KILL:
 125         case KGDBEXIT_CONTINUE:
 126                 set_msr(msr);
 127                 break;
 128
 129         case KGDBEXIT_SINGLE:
 130                 regs->msr |= MSR_SE;
 131 #if 0
 132                 set_msr(msr | MSR_SE);
 133 #endif
 134                 break;
 135         }
 136 }
 137
 138 int
 139 kgdb_trap(struct pt_regs *regs)
 140 {
 141         return (regs->trap);
 142 }
 143
 144 /* return the value of the CPU registers.
 145  * some of them are non-PowerPC names :(
 146  * they are stored in gdb like:
 147  * struct {
 148  *     u32 gpr[32];
 149  *     f64 fpr[32];
 150  *     u32 pc, ps, cnd, lr; (ps=msr)
 151  *     u32 cnt, xer, mq;
 152  * }
 153  */
 154
 155 #define SPACE_REQUIRED  ((32*4)+(32*8)+(6*4))
 156
 157 #ifdef CONFIG_8260
 158 /* store floating double indexed */
 159 #define STFDI(n,p)      __asm__ __volatile__ ("stfd " #n ",%0" : "=o"(p[2*n]))
 160 /* store floating double multiple */
 161 #define STFDM(p)        { STFDI( 0,p); STFDI( 1,p); STFDI( 2,p); STFDI( 3,p); \
 162                           STFDI( 4,p); STFDI( 5,p); STFDI( 6,p); STFDI( 7,p); \
 163                           STFDI( 8,p); STFDI( 9,p); STFDI(10,p); STFDI(11,p); \
 164                           STFDI(12,p); STFDI(13,p); STFDI(14,p); STFDI(15,p); \
 165                           STFDI(16,p); STFDI(17,p); STFDI(18,p); STFDI(19,p); \
 166                           STFDI(20,p); STFDI(21,p); STFDI(22,p); STFDI(23,p); \
 167                           STFDI(24,p); STFDI(25,p); STFDI(26,p); STFDI(27,p); \
 168                           STFDI(28,p); STFDI(29,p); STFDI(30,p); STFDI(31,p); }
 169 #endif
 170
 171 int
 172 kgdb_getregs(struct pt_regs *regs, char *buf, int max)
 173 {
 174         int i;
 175         unsigned long *ptr = (unsigned long *)buf;
 176
 177         if (max < SPACE_REQUIRED)
 178                 kgdb_error(KGDBERR_NOSPACE);
 179
 180         if ((unsigned long)ptr & 3)
 181                 kgdb_error(KGDBERR_ALIGNFAULT);
 182
 183         /* General Purpose Regs */
 184         for (i = 0; i < 32; i++)
 185                 *ptr++ = regs->gpr[i];
 186
 187         /* Floating Point Regs */
 188 #ifdef CONFIG_8260
 189         STFDM(ptr);
 190         ptr += 32*2;
 191 #else
 192         for (i = 0; i < 32; i++) {
 193                 *ptr++ = 0;
 194                 *ptr++ = 0;
 195         }
 196 #endif
 197
 198         /* pc, msr, cr, lr, ctr, xer, (mq is unused) */
 199         *ptr++ = regs->nip;
 200         *ptr++ = regs->msr;
 201         *ptr++ = regs->ccr;
 202         *ptr++ = regs->link;
 203         *ptr++ = regs->ctr;
 204         *ptr++ = regs->xer;
 205
 206         return (SPACE_REQUIRED);
 207 }
 208
 209 /* set the value of the CPU registers */
 210
 211 #ifdef CONFIG_8260
 212 /* load floating double */
 213 #define LFD(n,v)        __asm__ __volatile__ ("lfd " #n ",%0" :: "o"(v))
 214 /* load floating double indexed */
 215 #define LFDI(n,p)       __asm__ __volatile__ ("lfd " #n ",%0" :: "o"((p)[2*n]))
 216 /* load floating double multiple */
 217 #define LFDM(p)         { LFDI( 0,p); LFDI( 1,p); LFDI( 2,p); LFDI( 3,p); \
 218                           LFDI( 4,p); LFDI( 5,p); LFDI( 6,p); LFDI( 7,p); \
 219                           LFDI( 8,p); LFDI( 9,p); LFDI(10,p); LFDI(11,p); \
 220                           LFDI(12,p); LFDI(13,p); LFDI(14,p); LFDI(15,p); \
 221                           LFDI(16,p); LFDI(17,p); LFDI(18,p); LFDI(19,p); \
 222                           LFDI(20,p); LFDI(21,p); LFDI(22,p); LFDI(23,p); \
 223                           LFDI(24,p); LFDI(25,p); LFDI(26,p); LFDI(27,p); \
 224                           LFDI(28,p); LFDI(29,p); LFDI(30,p); LFDI(31,p); }
 225 #endif
 226
 227 void
 228 kgdb_putreg(struct pt_regs *regs, int regno, char *buf, int length)
 229 {
 230         unsigned long *ptr = (unsigned long *)buf;
 231
 232         if (regno < 0 || regno >= 70)
 233                 kgdb_error(KGDBERR_BADPARAMS);
 234         else if (regno >= 32 && regno < 64) {
 235                 if (length < 8)
 236                         kgdb_error(KGDBERR_NOSPACE);
 237         }
 238         else {
 239                 if (length < 4)
 240                         kgdb_error(KGDBERR_NOSPACE);
 241         }
 242
 243         if ((unsigned long)ptr & 3)
 244                 kgdb_error(KGDBERR_ALIGNFAULT);
 245
 246         if (regno >= 0 && regno < 32)
 247                 regs->gpr[regno] = *ptr;
 248         else switch (regno) {
 249
 250 #ifdef CONFIG_8260
 251 #define caseF(n) \
 252         case (n) + 32:  LFD(n, *ptr);           break;
 253
 254 caseF( 0) caseF( 1) caseF( 2) caseF( 3) caseF( 4) caseF( 5) caseF( 6) caseF( 7)
 255 caseF( 8) caseF( 9) caseF(10) caseF(11) caseF(12) caseF(13) caseF(14) caseF(15)
 256 caseF(16) caseF(17) caseF(18) caseF(19) caseF(20) caseF(21) caseF(22) caseF(23)
 257 caseF(24) caseF(25) caseF(26) caseF(27) caseF(28) caseF(29) caseF(30) caseF(31)
 258
 259 #undef caseF
 260 #endif
 261
 262         case 64:        regs->nip = *ptr;       break;
 263         case 65:        regs->msr = *ptr;       break;
 264         case 66:        regs->ccr = *ptr;       break;
 265         case 67:        regs->link = *ptr;      break;
 266         case 68:        regs->ctr = *ptr;       break;
 267         case 69:        regs->ctr = *ptr;       break;
 268
 269         default:
 270                 kgdb_error(KGDBERR_BADPARAMS);
 271         }
 272 }
 273
 274 void
 275 kgdb_putregs(struct pt_regs *regs, char *buf, int length)
 276 {
 277         int i;
 278         unsigned long *ptr = (unsigned long *)buf;
 279
 280         if (length < SPACE_REQUIRED)
 281                 kgdb_error(KGDBERR_NOSPACE);
 282
 283         if ((unsigned long)ptr & 3)
 284                 kgdb_error(KGDBERR_ALIGNFAULT);
 285
 286         /*
 287          * If the stack pointer has moved, you should pray.
 288          * (cause only god can help you).
 289          */
 290
 291         /* General Purpose Regs */
 292         for (i = 0; i < 32; i++)
 293                 regs->gpr[i] = *ptr++;
 294
 295         /* Floating Point Regs */
 296 #ifdef CONFIG_8260
 297         LFDM(ptr);
 298 #endif
 299         ptr += 32*2;
 300
 301         /* pc, msr, cr, lr, ctr, xer, (mq is unused) */
 302         regs->nip = *ptr++;
 303         regs->msr = *ptr++;
 304         regs->ccr = *ptr++;
 305         regs->link = *ptr++;
 306         regs->ctr = *ptr++;
 307         regs->xer = *ptr++;
 308 }
 309
 310 /* This function will generate a breakpoint exception.  It is used at the
 311    beginning of a program to sync up with a debugger and can be used
 312    otherwise as a quick means to stop program execution and "break" into
 313    the debugger. */
 314
 315 void
 316 kgdb_breakpoint(int argc, char *argv[])
 317 {
 318         asm("   .globl breakinst\n\
 319              breakinst: .long 0x7d821008\n\
 320             ");
 321 }