src/runtime/alpha-arch.c

   1 /*
   2  * This software is part of the SBCL system. See the README file for
   3  * more information.
   4  *
   5  * This software is derived from the CMU CL system, which was
   6  * written at Carnegie Mellon University and released into the
   7  * public domain. The software is in the public domain and is
   8  * provided with absolutely no warranty. See the COPYING and CREDITS
   9  * files for more information.
  10  */
  11
  12 /* Note that although superficially it appears that we use
  13  * os_context_t like we ought to, we actually just assume its a
  14  * ucontext in places.  Naughty */
  15
  16 #include <stdio.h>
  17 #include <string.h>
  18 #include <asm/pal.h>            /* for PAL_gentrap */
  19
  20 #include "runtime.h"
  21 #include "sbcl.h"
  22 #include "globals.h"
  23 #include "validate.h"
  24 #include "os.h"
  25 #include "arch.h"
  26 #include "lispregs.h"
  27 #include "signal.h"
  28 #include "alloc.h"
  29 #include "interrupt.h"
  30 #include "interr.h"
  31 #include "breakpoint.h"
  32 #include "monitor.h"
  33
  34 extern char call_into_lisp_LRA[], call_into_lisp_end[];
  35 extern size_t os_vm_page_size;
  36 #define BREAKPOINT_INST 0x80
  37
  38 void
  39 arch_init(void)
  40 {
  41     /* This must be called _after_ os_init(), so that we know what the
  42      * page size is. */
  43     if (mmap((os_vm_address_t) call_into_lisp_LRA_page,os_vm_page_size,
  44              OS_VM_PROT_ALL,MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,-1,0)
  45         == (os_vm_address_t) -1)
  46         perror("mmap");
  47
  48     /* call_into_lisp_LRA is a collection of trampolines written in asm -
  49      * see alpha-assem.S.  We copy it to call_into_lisp_LRA_page where
  50      * VOPs and things can find it. (I don't know why they can't find it
  51      * where it was to start with.) */
  52     bcopy(call_into_lisp_LRA,(void *)call_into_lisp_LRA_page,os_vm_page_size);
  53
  54     os_flush_icache((os_vm_address_t)call_into_lisp_LRA_page,
  55                     os_vm_page_size);
  56     return;
  57 }
  58
  59 os_vm_address_t
  60 arch_get_bad_addr (int sig, siginfo_t *code, os_context_t *context)
  61 {
  62     unsigned int badinst;
  63
  64     /* Instructions are 32 bit quantities. */
  65     unsigned int *pc ;
  66     /*  fprintf(stderr,"arch_get_bad_addr %d %p %p\n",
  67         sig, code, context); */
  68     pc= (unsigned int *)(*os_context_pc_addr(context));
  69
  70     if (((unsigned long)pc) & 3) {
  71         return NULL;            /* In what case would pc be unaligned?? */
  72     }
  73
  74     if ( (pc < READ_ONLY_SPACE_START ||
  75           pc >= READ_ONLY_SPACE_START+READ_ONLY_SPACE_SIZE) &&
  76          (pc < current_dynamic_space ||
  77           pc >= current_dynamic_space + DYNAMIC_SPACE_SIZE))
  78         return NULL;
  79
  80     badinst = *pc;
  81
  82     if (((badinst>>27)!=0x16)   /* STL or STQ */
  83         && ((badinst>>27)!=0x13)) /* STS or STT */
  84         return NULL;            /* Otherwise forget about address. */
  85
  86     return (os_vm_address_t)
  87         (*os_context_register_addr(context,((badinst>>16)&0x1f))
  88          +(badinst&0xffff));
  89 }
  90
  91 void
  92 arch_skip_instruction(os_context_t *context)
  93 {
  94     /* This may be complete rubbish, as (at least for traps) pc points
  95      * _after_ the instruction that caused us to be here anyway.
  96      */
  97     ((char*)*os_context_pc_addr(context)) +=4; }
  98
  99 unsigned char *
 100 arch_internal_error_arguments(os_context_t *context)
 101 {
 102     return (unsigned char *)(*os_context_pc_addr(context)+4);
 103 }
 104
 105 boolean
 106 arch_pseudo_atomic_atomic(os_context_t *context)
 107 {
 108     return ((*os_context_register_addr(context,reg_ALLOC)) & 1);
 109 }
 110
 111 void arch_set_pseudo_atomic_interrupted(os_context_t *context)
 112 {
 113     /* On coming out of an atomic section, we subtract 1 from
 114      * reg_Alloc, then try to store something at that address.  On
 115      * OSF/1 we add 1 to reg_Alloc here so that the end-of-atomic code
 116      * will raise SIGTRAP for "unaligned access".  Linux catches
 117      * unaligned accesses in the kernel and fixes them up[1], so there
 118      * we toggle bit 63 instead.  The resulting address is somewhere
 119      * out in no-man's land, so we get SIGSEGV when we try to access
 120      * it.  We catch whichever signal it is (see the appropriate
 121      * *-os.c) and call interrupt_handle_pending() from it */
 122
 123     /* [1] This behaviour can be changed with osf_setsysinfo, but cmucl
 124      * didn't use that */
 125
 126 #ifdef __linux__
 127     *os_context_register_addr(context,reg_ALLOC) |=  (1L<<63);
 128 #else
 129     *os_context_register_addr(context,reg_ALLOC) |=  2;
 130 #endif
 131 }
 132
 133 /* XXX but is the caller of this storing all 64 bits? */
 134 unsigned long arch_install_breakpoint(void *pc)
 135 {
 136     unsigned int *ptr = (unsigned int *)pc;
 137     unsigned long result = (unsigned long) *ptr;
 138     *ptr = BREAKPOINT_INST;
 139
 140     os_flush_icache((os_vm_address_t)ptr, sizeof(unsigned long));
 141
 142     return result;
 143 }
 144
 145 void arch_remove_breakpoint(void *pc, unsigned long orig_inst)
 146 {
 147     /* was (unsigned int) but gcc complains.  Changed to mirror
 148      * install_breakpoint() above */
 149     unsigned long *ptr=(unsigned long *)pc;
 150     *ptr = orig_inst;
 151     os_flush_icache((os_vm_address_t)pc, sizeof(unsigned long));
 152 }
 153
 154 static unsigned int *skipped_break_addr, displaced_after_inst,
 155      after_breakpoint;
 156
 157
 158 /* This returns a PC value.  Lisp code is all in the 32-bit-addressable
 159  * space, so we should be ok with an unsigned int. */
 160 unsigned int
 161 emulate_branch(os_context_t *context,unsigned long orig_inst)
 162 {
 163     int op = orig_inst >> 26;
 164     int reg_a = (orig_inst >> 21) & 0x1f;
 165     int reg_b = (orig_inst >> 16) & 0x1f;
 166     int disp =
 167         (orig_inst&(1<<20)) ?
 168         orig_inst | (-1 << 21) :
 169         orig_inst&0x1fffff;
 170     int next_pc = *os_context_pc_addr(context);
 171     int branch = 0; /* was NULL;               */
 172
 173     switch(op) {
 174     case 0x1a: /* jmp, jsr, jsr_coroutine, ret */
 175         *os_context_register_addr(context,reg_a) =
 176             *os_context_pc_addr(context);
 177         *os_context_pc_addr(context) =
 178             *os_context_register_addr(context,reg_b)& ~3;
 179         break;
 180     case 0x30: /* br */
 181         *os_context_register_addr(context,reg_a)=*os_context_pc_addr(context);
 182         branch = 1;
 183         break;
 184     case 0x31: /* fbeq */
 185         if (*(os_context_float_register_addr(context,reg_a))==0) branch = 1;
 186         break;
 187     case 0x32: /* fblt */
 188         if (*os_context_float_register_addr(context,reg_a)<0) branch = 1;
 189         break;
 190     case 0x33: /* fble */
 191         if (*os_context_float_register_addr(context,reg_a)<=0) branch = 1;
 192         break;
 193     case 0x34: /* bsr */
 194         *os_context_register_addr(context,reg_a)=*os_context_pc_addr(context);
 195         branch = 1;
 196         break;
 197     case 0x35: /* fbne */
 198         if (*os_context_register_addr(context,reg_a)!=0) branch = 1;
 199         break;
 200     case 0x36: /* fbge */
 201         if (*os_context_float_register_addr(context,reg_a)>=0) branch = 1;
 202         break;
 203     case 0x37: /* fbgt */
 204         if (*os_context_float_register_addr(context,reg_a)>0) branch = 1;
 205         break;
 206     case 0x38: /* blbc */
 207         if ((*os_context_register_addr(context,reg_a)&1) == 0) branch = 1;
 208         break;
 209     case 0x39: /* beq */
 210         if (*os_context_register_addr(context,reg_a)==0) branch = 1;
 211         break;
 212     case 0x3a: /* blt */
 213         if (*os_context_register_addr(context,reg_a)<0) branch = 1;
 214         break;
 215     case 0x3b: /* ble */
 216         if (*os_context_register_addr(context,reg_a)<=0) branch = 1;
 217         break;
 218     case 0x3c: /* blbs */
 219         if ((*os_context_register_addr(context,reg_a)&1)!=0) branch = 1;
 220         break;
 221     case 0x3d: /* bne */
 222         if (*os_context_register_addr(context,reg_a)!=0) branch = 1;
 223         break;
 224     case 0x3e: /* bge */
 225         if (*os_context_register_addr(context,reg_a)>=0) branch = 1;
 226         break;
 227     case 0x3f: /* bgt */
 228         if (*os_context_register_addr(context,reg_a)>0) branch = 1;
 229         break;
 230     }
 231     if (branch)
 232         next_pc += disp*4;
 233     return next_pc;
 234 }
 235
 236 static sigset_t orig_sigmask;
 237
 238 /* Perform the instruction that we overwrote with a breakpoint.  As we
 239  * don't have a single-step facility, this means we have to:
 240  * - put the instruction back
 241  * - put a second breakpoint at the following instruction,
 242  *   set after_breakpoint and continue execution.
 243  *
 244  * When the second breakpoint is hit (very shortly thereafter, we hope)
 245  * sigtrap_handler gets called again, but follows the AfterBreakpoint
 246  * arm, which
 247  * - puts a bpt back in the first breakpoint place (running across a
 248  *   breakpoint shouldn't cause it to be uninstalled)
 249  * - replaces the second bpt with the instruction it was meant to be
 250  * - carries on
 251  *
 252  * Clear?
 253  */
 254
 255 void arch_do_displaced_inst(os_context_t *context,unsigned int orig_inst)
 256 {
 257     /* Apparent off-by-one errors ahoy.  If you consult the Alpha ARM,
 258      * it will tell you that after a BPT, the saved PC is the address
 259      * of the instruction _after_ the instruction that caused the trap.
 260      *
 261      * However, we decremented PC by 4 before calling the Lisp-level
 262      * handler that calls this routine (see alpha-arch.c line 322 and
 263      * friends) so when we get to this point PC is actually pointing
 264      * at the BPT instruction itself.  This is good, because this is
 265      * where we want to restart execution when we do that */
 266
 267     unsigned int *pc=(unsigned int *)(*os_context_pc_addr(context));
 268     unsigned int *next_pc;
 269     int op = orig_inst >> 26;;
 270
 271     orig_sigmask = *os_context_sigmask_addr(context);
 272     sigaddset_blockable(os_context_sigmask_addr(context));
 273
 274     /* Put the original instruction back. */
 275     *pc = orig_inst;
 276     os_flush_icache((os_vm_address_t)pc, sizeof(unsigned long));
 277     skipped_break_addr = pc;
 278
 279     /* Figure out where we will end up after running the displaced
 280      * instruction */
 281     if (op == 0x1a || (op&0xf) == 0x30) /* a branch */
 282         /* The cast to long is just to shut gcc up. */
 283         next_pc = (unsigned int *)((long)emulate_branch(context,orig_inst));
 284     else
 285         next_pc = pc+1;
 286
 287     /* Set the after breakpoint. */
 288     displaced_after_inst = *next_pc;
 289     *next_pc = BREAKPOINT_INST;
 290     after_breakpoint=1;
 291     os_flush_icache((os_vm_address_t)next_pc, sizeof(unsigned long));
 292 }
 293
 294 static void
 295 sigtrap_handler(int signal, siginfo_t *siginfo, os_context_t *context)
 296 {
 297     unsigned int code;
 298
 299     /* Don't disallow recursive breakpoint traps.  Otherwise, we can't */
 300     /* use debugger breakpoints anywhere in here. */
 301     sigset_t *mask=(os_context_sigmask_addr(context));
 302     sigsetmask(mask);
 303
 304     /* this is different from how CMUCL does it.  CMUCL used "call_pal
 305      * PAL_gentrap", which doesn't do anything on Linux (unless NL0
 306      * contains certain specific values).  We use "bugchk" instead.
 307      * It's (for our purposes) just the same as bpt but has a
 308      * different opcode so we can test whether we're dealing with a
 309      * breakpoint or a "system service" */
 310
 311     if ((*(unsigned int*)(*os_context_pc_addr(context)-4))==BREAKPOINT_INST) {
 312         if (after_breakpoint) {
 313             /* see comments above arch_do_displaced_inst.  This is where
 314              * we reinsert the breakpoint that we removed earlier */
 315
 316             *os_context_pc_addr(context) -=4;
 317             *skipped_break_addr = BREAKPOINT_INST;
 318             os_flush_icache((os_vm_address_t)skipped_break_addr,
 319                             sizeof(unsigned long));
 320             skipped_break_addr = NULL;
 321             *(unsigned int *)*os_context_pc_addr(context) =
 322                 displaced_after_inst;
 323             os_flush_icache((os_vm_address_t)*os_context_pc_addr(context), sizeof(unsigned long));
 324             *os_context_sigmask_addr(context)= orig_sigmask;
 325             after_breakpoint=0; /* false */
 326             return;
 327         } else
 328             code = trap_Breakpoint;
 329     } else
 330         /* a "system service" */
 331     code=*((u32 *)(*os_context_pc_addr(context)));
 332
 333     switch (code) {
 334       case trap_PendingInterrupt:
 335         arch_skip_instruction(context);
 336         interrupt_handle_pending(context);
 337         break;
 338
 339       case trap_Halt:
 340         fake_foreign_function_call(context);
 341         lose("%%primitive halt called; the party is over.\n");
 342
 343       case trap_Error:
 344       case trap_Cerror:
 345         interrupt_internal_error(signal, siginfo, context, code==trap_Cerror);
 346         break;
 347
 348     case trap_Breakpoint:        /* call lisp-level handler */
 349         *os_context_pc_addr(context) -=4;
 350         handle_breakpoint(signal, siginfo, context);
 351         break;
 352
 353       case trap_FunEndBreakpoint:
 354         *os_context_pc_addr(context) -=4;
 355         *os_context_pc_addr(context) =
 356             (int)handle_fun_end_breakpoint(signal, siginfo, context);
 357         break;
 358
 359       default:
 360         fprintf(stderr, "unidetified breakpoint/trap %d\n",code);
 361         interrupt_handle_now(signal, siginfo, context);
 362         break;
 363     }
 364 }
 365
 366 unsigned long
 367 arch_get_fp_control()
 368 {
 369     return ieee_get_fp_control();
 370 }
 371
 372 void
 373 arch_set_fp_control(unsigned long fp)
 374 {
 375     ieee_set_fp_control(fp);
 376 }
 377
 378
 379 void arch_install_interrupt_handlers()
 380 {
 381     undoably_install_low_level_interrupt_handler(SIGTRAP, sigtrap_handler);
 382 }
 383
 384 extern lispobj call_into_lisp(lispobj fun, lispobj *args, int nargs);
 385
 386 lispobj funcall0(lispobj function)
 387 {
 388     lispobj *args = current_control_stack_pointer;
 389
 390     return call_into_lisp(function, args, 0);
 391 }
 392
 393 lispobj funcall1(lispobj function, lispobj arg0)
 394 {
 395     lispobj *args = current_control_stack_pointer;
 396
 397     current_control_stack_pointer += 1;
 398     args[0] = arg0;
 399
 400     return call_into_lisp(function, args, 1);
 401 }
 402
 403 lispobj funcall2(lispobj function, lispobj arg0, lispobj arg1)
 404 {
 405     lispobj *args = current_control_stack_pointer;
 406
 407     current_control_stack_pointer += 2;
 408     args[0] = arg0;
 409     args[1] = arg1;
 410
 411     return call_into_lisp(function, args, 2);
 412 }
 413
 414 lispobj funcall3(lispobj function, lispobj arg0, lispobj arg1, lispobj arg2)
 415 {
 416     lispobj *args = current_control_stack_pointer;
 417
 418     current_control_stack_pointer += 3;
 419     args[0] = arg0;
 420     args[1] = arg1;
 421     args[2] = arg2;
 422
 423     return call_into_lisp(function, args, 3);
 424 }
 425