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
  19 #include "runtime.h"
  20 #include "sbcl.h"
  21 #include "globals.h"
  22 #include "validate.h"
  23 #include "os.h"
  24 #include "arch.h"
  25 #include "lispregs.h"
  26 #include "signal.h"
  27 #include "alloc.h"
  28 #include "interrupt.h"
  29 #include "interr.h"
  30 #include "breakpoint.h"
  31 #include "monitor.h"
  32
  33 extern char call_into_lisp_LRA[], call_into_lisp_end[];
  34
  35 extern size_t os_vm_page_size;
  36 #define BREAKPOINT_INST 0x80
  37
  38
  39 void
  40 arch_init(void)
  41 {
  42     /* This must be called _after_ os_init(), so that we know what the
  43      * page size is. */
  44
  45     if (mmap((os_vm_address_t) call_into_lisp_LRA_page,os_vm_page_size,
  46              OS_VM_PROT_ALL,MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,-1,0)
  47         == (os_vm_address_t) -1)
  48         perror("mmap");
  49
  50     /* call_into_lisp_LRA is a collection of trampolines written in asm -
  51      * see alpha-assem.S.  We copy it to call_into_lisp_LRA_page where
  52      * VOPs and things can find it. (I don't know why they can't find it
  53      * where it was to start with.) */
  54     bcopy(call_into_lisp_LRA,(void *)call_into_lisp_LRA_page,os_vm_page_size);
  55
  56     os_flush_icache((os_vm_address_t)call_into_lisp_LRA_page,
  57                     os_vm_page_size);
  58     return;
  59 }
  60
  61 os_vm_address_t
  62 arch_get_bad_addr (int sig, siginfo_t *code, os_context_t *context)
  63 {
  64     unsigned int badinst;
  65
  66     /* Instructions are 32 bit quantities. */
  67     unsigned int *pc ;
  68     /*  fprintf(stderr,"arch_get_bad_addr %d %p %p\n",
  69         sig, code, context); */
  70     pc= (unsigned int *)(*os_context_pc_addr(context));
  71
  72     if (((unsigned long)pc) & 3) {
  73         return NULL;            /* In what case would pc be unaligned?? */
  74     }
  75
  76     if ( (pc < READ_ONLY_SPACE_START ||
  77           pc >= READ_ONLY_SPACE_START+READ_ONLY_SPACE_SIZE) &&
  78          (pc < current_dynamic_space ||
  79           pc >= current_dynamic_space + DYNAMIC_SPACE_SIZE))
  80         return NULL;
  81
  82     return context->uc_mcontext.sc_traparg_a0;
  83 }
  84
  85 void
  86 arch_skip_instruction(os_context_t *context)
  87 {
  88     /* This may be complete rubbish, as (at least for traps) pc points
  89      * _after_ the instruction that caused us to be here anyway.
  90      */
  91     ((char*)*os_context_pc_addr(context)) +=4; }
  92
  93 unsigned char *
  94 arch_internal_error_arguments(os_context_t *context)
  95 {
  96     return (unsigned char *)(*os_context_pc_addr(context)+4);
  97 }
  98
  99 boolean
 100 arch_pseudo_atomic_atomic(os_context_t *context)
 101 {
 102     return ((*os_context_register_addr(context,reg_ALLOC)) & 1);
 103 }
 104
 105 void arch_set_pseudo_atomic_interrupted(os_context_t *context)
 106 {
 107     /* On coming out of an atomic section, we subtract 1 from
 108      * reg_Alloc, then try to store something at that address.  So,
 109      * to signal that it was interrupted and a signal should be handled,
 110      * we set bit 63 of reg_ALLOC here so that the end-of-atomic code
 111      * will raise SIGSEGV (no ram mapped there).  We catch the signal
 112      * (see the appropriate *-os.c) and call interrupt_handle_pending()
 113      * for the saved signal instead */
 114
 115     *os_context_register_addr(context,reg_ALLOC) |=  (1L<<63);
 116 }
 117
 118 unsigned long arch_install_breakpoint(void *pc)
 119 {
 120     unsigned int *ptr = (unsigned int *)pc;
 121     unsigned long result = (unsigned long) *ptr;
 122     *ptr = BREAKPOINT_INST;
 123
 124     os_flush_icache((os_vm_address_t)ptr, sizeof(unsigned long));
 125
 126     return result;
 127 }
 128
 129 void arch_remove_breakpoint(void *pc, unsigned long orig_inst)
 130 {
 131     /* was (unsigned int) but gcc complains.  Changed to mirror
 132      * install_breakpoint() above */
 133     unsigned long *ptr=(unsigned long *)pc;
 134     *ptr = orig_inst;
 135     os_flush_icache((os_vm_address_t)pc, sizeof(unsigned long));
 136 }
 137
 138 static unsigned int *skipped_break_addr, displaced_after_inst,
 139      after_breakpoint;
 140
 141
 142 /* This returns a PC value.  Lisp code is all in the 32-bit-addressable
 143  * space, so we should be ok with an unsigned int. */
 144 unsigned int
 145 emulate_branch(os_context_t *context,unsigned long orig_inst)
 146 {
 147     int op = orig_inst >> 26;
 148     int reg_a = (orig_inst >> 21) & 0x1f;
 149     int reg_b = (orig_inst >> 16) & 0x1f;
 150     int disp =
 151         (orig_inst&(1<<20)) ?
 152         orig_inst | (-1 << 21) :
 153         orig_inst&0x1fffff;
 154     int next_pc = *os_context_pc_addr(context);
 155     int branch = 0; /* was NULL;               */
 156
 157     switch(op) {
 158     case 0x1a: /* jmp, jsr, jsr_coroutine, ret */
 159         *os_context_register_addr(context,reg_a) =
 160             *os_context_pc_addr(context);
 161         *os_context_pc_addr(context) =
 162             *os_context_register_addr(context,reg_b)& ~3;
 163         break;
 164     case 0x30: /* br */
 165         *os_context_register_addr(context,reg_a)=*os_context_pc_addr(context);
 166         branch = 1;
 167         break;
 168     case 0x31: /* fbeq */
 169         if (*(os_context_float_register_addr(context,reg_a))==0) branch = 1;
 170         break;
 171     case 0x32: /* fblt */
 172         if (*os_context_float_register_addr(context,reg_a)<0) branch = 1;
 173         break;
 174     case 0x33: /* fble */
 175         if (*os_context_float_register_addr(context,reg_a)<=0) branch = 1;
 176         break;
 177     case 0x34: /* bsr */
 178         *os_context_register_addr(context,reg_a)=*os_context_pc_addr(context);
 179         branch = 1;
 180         break;
 181     case 0x35: /* fbne */
 182         if (*os_context_register_addr(context,reg_a)!=0) branch = 1;
 183         break;
 184     case 0x36: /* fbge */
 185         if (*os_context_float_register_addr(context,reg_a)>=0) branch = 1;
 186         break;
 187     case 0x37: /* fbgt */
 188         if (*os_context_float_register_addr(context,reg_a)>0) branch = 1;
 189         break;
 190     case 0x38: /* blbc */
 191         if ((*os_context_register_addr(context,reg_a)&1) == 0) branch = 1;
 192         break;
 193     case 0x39: /* beq */
 194         if (*os_context_register_addr(context,reg_a)==0) branch = 1;
 195         break;
 196     case 0x3a: /* blt */
 197         if (*os_context_register_addr(context,reg_a)<0) branch = 1;
 198         break;
 199     case 0x3b: /* ble */
 200         if (*os_context_register_addr(context,reg_a)<=0) branch = 1;
 201         break;
 202     case 0x3c: /* blbs */
 203         if ((*os_context_register_addr(context,reg_a)&1)!=0) branch = 1;
 204         break;
 205     case 0x3d: /* bne */
 206         if (*os_context_register_addr(context,reg_a)!=0) branch = 1;
 207         break;
 208     case 0x3e: /* bge */
 209         if (*os_context_register_addr(context,reg_a)>=0) branch = 1;
 210         break;
 211     case 0x3f: /* bgt */
 212         if (*os_context_register_addr(context,reg_a)>0) branch = 1;
 213         break;
 214     }
 215     if (branch)
 216         next_pc += disp*4;
 217     return next_pc;
 218 }
 219
 220 static sigset_t orig_sigmask;
 221
 222 /* Perform the instruction that we overwrote with a breakpoint.  As we
 223  * don't have a single-step facility, this means we have to:
 224  * - put the instruction back
 225  * - put a second breakpoint at the following instruction,
 226  *   set after_breakpoint and continue execution.
 227  *
 228  * When the second breakpoint is hit (very shortly thereafter, we hope)
 229  * sigtrap_handler gets called again, but follows the AfterBreakpoint
 230  * arm, which
 231  * - puts a bpt back in the first breakpoint place (running across a
 232  *   breakpoint shouldn't cause it to be uninstalled)
 233  * - replaces the second bpt with the instruction it was meant to be
 234  * - carries on
 235  *
 236  * Clear?
 237  */
 238
 239 void arch_do_displaced_inst(os_context_t *context,unsigned int orig_inst)
 240 {
 241     /* Apparent off-by-one errors ahoy.  If you consult the Alpha ARM,
 242      * it will tell you that after a BPT, the saved PC is the address
 243      * of the instruction _after_ the instruction that caused the trap.
 244      *
 245      * However, we decremented PC by 4 before calling the Lisp-level
 246      * handler that calls this routine (see alpha-arch.c line 322 and
 247      * friends) so when we get to this point PC is actually pointing
 248      * at the BPT instruction itself.  This is good, because this is
 249      * where we want to restart execution when we do that */
 250
 251     unsigned int *pc=(unsigned int *)(*os_context_pc_addr(context));
 252     unsigned int *next_pc;
 253     int op = orig_inst >> 26;;
 254
 255     orig_sigmask = *os_context_sigmask_addr(context);
 256     sigaddset_blockable(os_context_sigmask_addr(context));
 257
 258     /* Put the original instruction back. */
 259     *pc = orig_inst;
 260     os_flush_icache((os_vm_address_t)pc, sizeof(unsigned long));
 261     skipped_break_addr = pc;
 262
 263     /* Figure out where we will end up after running the displaced
 264      * instruction */
 265     if (op == 0x1a || (op&0xf) == 0x30) /* a branch */
 266         /* The cast to long is just to shut gcc up. */
 267         next_pc = (unsigned int *)((long)emulate_branch(context,orig_inst));
 268     else
 269         next_pc = pc+1;
 270
 271     /* Set the after breakpoint. */
 272     displaced_after_inst = *next_pc;
 273     *next_pc = BREAKPOINT_INST;
 274     after_breakpoint=1;
 275     os_flush_icache((os_vm_address_t)next_pc, sizeof(unsigned long));
 276 }
 277
 278 static void
 279 sigtrap_handler(int signal, siginfo_t *siginfo, os_context_t *context)
 280 {
 281     unsigned int code;
 282     sigset_t *mask;
 283 #ifdef LISP_FEATURE_LINUX
 284     os_restore_fp_control(context);
 285 #endif
 286
 287     /* Don't disallow recursive breakpoint traps.  Otherwise, we can't */
 288     /* use debugger breakpoints anywhere in here. */
 289     mask=(os_context_sigmask_addr(context));
 290     sigsetmask(mask);
 291
 292     /* this is different from how CMUCL does it.  CMUCL used "call_pal
 293      * PAL_gentrap", which doesn't do anything on Linux (unless NL0
 294      * contains certain specific values).  We use "bugchk" instead.
 295      * It's (for our purposes) just the same as bpt but has a
 296      * different opcode so we can test whether we're dealing with a
 297      * breakpoint or a "system service" */
 298
 299     if ((*(unsigned int*)(*os_context_pc_addr(context)-4))==BREAKPOINT_INST) {
 300         if (after_breakpoint) {
 301             /* see comments above arch_do_displaced_inst.  This is where
 302              * we reinsert the breakpoint that we removed earlier */
 303
 304             *os_context_pc_addr(context) -=4;
 305             *skipped_break_addr = BREAKPOINT_INST;
 306             os_flush_icache((os_vm_address_t)skipped_break_addr,
 307                             sizeof(unsigned long));
 308             skipped_break_addr = NULL;
 309             *(unsigned int *)*os_context_pc_addr(context) =
 310                 displaced_after_inst;
 311             os_flush_icache((os_vm_address_t)*os_context_pc_addr(context), sizeof(unsigned long));
 312             *os_context_sigmask_addr(context)= orig_sigmask;
 313             after_breakpoint=0; /* false */
 314             return;
 315         } else
 316             code = trap_Breakpoint;
 317     } else
 318         /* a "system service" */
 319     code=*((u32 *)(*os_context_pc_addr(context)));
 320
 321     switch (code) {
 322       case trap_PendingInterrupt:
 323         arch_skip_instruction(context);
 324         interrupt_handle_pending(context);
 325         break;
 326
 327       case trap_Halt:
 328         fake_foreign_function_call(context);
 329         lose("%%primitive halt called; the party is over.\n");
 330
 331       case trap_Error:
 332       case trap_Cerror:
 333         interrupt_internal_error(signal, siginfo, context, code==trap_Cerror);
 334         break;
 335
 336     case trap_Breakpoint:        /* call lisp-level handler */
 337         *os_context_pc_addr(context) -=4;
 338         handle_breakpoint(signal, siginfo, context);
 339         break;
 340
 341       case trap_FunEndBreakpoint:
 342         *os_context_pc_addr(context) -=4;
 343         *os_context_pc_addr(context) =
 344             (int)handle_fun_end_breakpoint(signal, siginfo, context);
 345         break;
 346
 347       default:
 348         fprintf(stderr, "unidentified breakpoint/trap %d\n",code);
 349         interrupt_handle_now(signal, siginfo, context);
 350         break;
 351     }
 352 }
 353
 354 unsigned long
 355 arch_get_fp_control()
 356 {
 357     return ieee_get_fp_control();
 358 }
 359
 360 void
 361 arch_set_fp_control(unsigned long fp)
 362 {
 363     ieee_set_fp_control(fp);
 364 }
 365
 366
 367 void arch_install_interrupt_handlers()
 368 {
 369     undoably_install_low_level_interrupt_handler(SIGTRAP, sigtrap_handler);
 370 }
 371
 372 extern lispobj call_into_lisp(lispobj fun, lispobj *args, int nargs);
 373
 374 lispobj funcall0(lispobj function)
 375 {
 376     lispobj *args = current_control_stack_pointer;
 377
 378     return call_into_lisp(function, args, 0);
 379 }
 380
 381 lispobj funcall1(lispobj function, lispobj arg0)
 382 {
 383     lispobj *args = current_control_stack_pointer;
 384
 385     current_control_stack_pointer += 1;
 386     args[0] = arg0;
 387
 388     return call_into_lisp(function, args, 1);
 389 }
 390
 391 lispobj funcall2(lispobj function, lispobj arg0, lispobj arg1)
 392 {
 393     lispobj *args = current_control_stack_pointer;
 394
 395     current_control_stack_pointer += 2;
 396     args[0] = arg0;
 397     args[1] = arg1;
 398
 399     return call_into_lisp(function, args, 2);
 400 }
 401
 402 lispobj funcall3(lispobj function, lispobj arg0, lispobj arg1, lispobj arg2)
 403 {
 404     lispobj *args = current_control_stack_pointer;
 405
 406     current_control_stack_pointer += 3;
 407     args[0] = arg0;
 408     args[1] = arg1;
 409     args[2] = arg2;
 410
 411     return call_into_lisp(function, args, 3);
 412 }
 413