src/runtime/x86-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 #include <stdio.h>
  13
  14 #include "runtime.h"
  15 #include "globals.h"
  16 #include "validate.h"
  17 #include "os.h"
  18 #include "sbcl.h"
  19 #include "arch.h"
  20 #include "lispregs.h"
  21 #include "signal.h"
  22 #include "alloc.h"
  23 #include "interrupt.h"
  24 #include "interr.h"
  25 #include "breakpoint.h"
  26 #include "monitor.h"
  27
  28 #include "genesis/static-symbols.h"
  29 #include "genesis/symbol.h"
  30
  31 #define BREAKPOINT_INST 0xcc    /* INT3 */
  32
  33 unsigned long fast_random_state = 1;
  34
  35 void arch_init(void)
  36 {}
  37 \f
  38 /*
  39  * hacking signal contexts
  40  *
  41  * (This depends both on architecture, which determines what we might
  42  * want to get to, and on OS, which determines how we get to it.)
  43  */
  44
  45 int *
  46 context_eflags_addr(os_context_t *context)
  47 {
  48 #if defined __linux__
  49     /* KLUDGE: As of kernel 2.2.14 on Red Hat 6.2, there's code in the
  50      * <sys/ucontext.h> file to define symbolic names for offsets into
  51      * gregs[], but it's conditional on __USE_GNU and not defined, so
  52      * we need to do this nasty absolute index magic number thing
  53      * instead. */
  54     return &context->uc_mcontext.gregs[16];
  55 #elif defined __FreeBSD__
  56     return &context->uc_mcontext.mc_eflags;
  57 #elif defined __OpenBSD__
  58     return &context->sc_eflags;
  59 #else
  60 #error unsupported OS
  61 #endif
  62 }
  63 \f
  64 void arch_skip_instruction(os_context_t *context)
  65 {
  66     /* Assuming we get here via an INT3 xxx instruction, the PC now
  67      * points to the interrupt code (a Lisp value) so we just move
  68      * past it. Skip the code; after that, if the code is an
  69      * error-trap or cerror-trap then skip the data bytes that follow. */
  70
  71     int vlen;
  72     int code;
  73
  74     FSHOW((stderr, "/[arch_skip_inst at %x]\n", *os_context_pc_addr(context)));
  75
  76     /* Get and skip the Lisp interrupt code. */
  77     code = *(char*)(*os_context_pc_addr(context))++;
  78     switch (code)
  79         {
  80         case trap_Error:
  81         case trap_Cerror:
  82             /* Lisp error arg vector length */
  83             vlen = *(char*)(*os_context_pc_addr(context))++;
  84             /* Skip Lisp error arg data bytes. */
  85             while (vlen-- > 0) {
  86                 ( (char*)(*os_context_pc_addr(context)) )++;
  87             }
  88             break;
  89
  90         case trap_Breakpoint:           /* not tested */
  91         case trap_FunEndBreakpoint: /* not tested */
  92             break;
  93
  94         case trap_PendingInterrupt:
  95         case trap_Halt:
  96             /* only needed to skip the Code */
  97             break;
  98
  99         default:
 100             fprintf(stderr,"[arch_skip_inst invalid code %d\n]\n",code);
 101             break;
 102         }
 103
 104     FSHOW((stderr,
 105            "/[arch_skip_inst resuming at %x]\n",
 106            *os_context_pc_addr(context)));
 107 }
 108
 109 unsigned char *
 110 arch_internal_error_arguments(os_context_t *context)
 111 {
 112     return 1 + (unsigned char *)(*os_context_pc_addr(context));
 113 }
 114
 115 boolean
 116 arch_pseudo_atomic_atomic(os_context_t *context)
 117 {
 118     return SymbolValue(PSEUDO_ATOMIC_ATOMIC);
 119 }
 120
 121 void
 122 arch_set_pseudo_atomic_interrupted(os_context_t *context)
 123 {
 124     SetSymbolValue(PSEUDO_ATOMIC_INTERRUPTED, make_fixnum(1));
 125 }
 126 \f
 127 /*
 128  * This stuff seems to get called for TRACE and debug activity.
 129  */
 130
 131 unsigned long
 132 arch_install_breakpoint(void *pc)
 133 {
 134     unsigned long result = *(unsigned long*)pc;
 135
 136     *(char*)pc = BREAKPOINT_INST;               /* x86 INT3       */
 137     *((char*)pc+1) = trap_Breakpoint;           /* Lisp trap code */
 138
 139     return result;
 140 }
 141
 142 void
 143 arch_remove_breakpoint(void *pc, unsigned long orig_inst)
 144 {
 145     *((char *)pc) = orig_inst & 0xff;
 146     *((char *)pc + 1) = (orig_inst & 0xff00) >> 8;
 147 }
 148 \f
 149 /* When single stepping, single_stepping holds the original instruction
 150  * PC location. */
 151 unsigned int *single_stepping = NULL;
 152 #ifdef CANNOT_GET_TO_SINGLE_STEP_FLAG
 153 unsigned int  single_step_save1;
 154 unsigned int  single_step_save2;
 155 unsigned int  single_step_save3;
 156 #endif
 157
 158 void
 159 arch_do_displaced_inst(os_context_t *context, unsigned int orig_inst)
 160 {
 161     unsigned int *pc = (unsigned int*)(*os_context_pc_addr(context));
 162
 163     /* Put the original instruction back. */
 164     *((char *)pc) = orig_inst & 0xff;
 165     *((char *)pc + 1) = (orig_inst & 0xff00) >> 8;
 166
 167 #ifdef CANNOT_GET_TO_SINGLE_STEP_FLAG
 168     /* Install helper instructions for the single step:
 169      * pushf; or [esp],0x100; popf. */
 170     single_step_save1 = *(pc-3);
 171     single_step_save2 = *(pc-2);
 172     single_step_save3 = *(pc-1);
 173     *(pc-3) = 0x9c909090;
 174     *(pc-2) = 0x00240c81;
 175     *(pc-1) = 0x9d000001;
 176 #else
 177     *context_eflags_addr(context) |= 0x100;
 178 #endif
 179
 180     single_stepping = (unsigned int*)pc;
 181
 182 #ifdef CANNOT_GET_TO_SINGLE_STEP_FLAG
 183     *os_context_pc_addr(context) = (char *)pc - 9;
 184 #endif
 185 }
 186 \f
 187 void
 188 sigtrap_handler(int signal, siginfo_t *info, void *void_context)
 189 {
 190     int code = info->si_code;
 191     os_context_t *context = (os_context_t*)void_context;
 192     unsigned int trap;
 193
 194     if (single_stepping && (signal==SIGTRAP))
 195     {
 196         /* fprintf(stderr,"* single step trap %x\n", single_stepping); */
 197
 198 #ifdef CANNOT_GET_TO_SINGLE_STEP_FLAG
 199         /* Un-install single step helper instructions. */
 200         *(single_stepping-3) = single_step_save1;
 201         *(single_stepping-2) = single_step_save2;
 202         *(single_stepping-1) = single_step_save3;
 203 #else
 204         *context_eflags_addr(context) ^= 0x100;
 205 #endif
 206         /* Re-install the breakpoint if possible. */
 207         if (*os_context_pc_addr(context) == (int)single_stepping + 1) {
 208             fprintf(stderr, "warning: couldn't reinstall breakpoint\n");
 209         } else {
 210             *((char *)single_stepping) = BREAKPOINT_INST;       /* x86 INT3 */
 211             *((char *)single_stepping+1) = trap_Breakpoint;
 212         }
 213
 214         single_stepping = NULL;
 215         return;
 216     }
 217
 218     /* This is just for info in case the monitor wants to print an
 219      * approximation. */
 220     current_control_stack_pointer =
 221         (lispobj *)*os_context_sp_addr(context);
 222
 223     /* FIXME: CMUCL puts the float control restoration code here.
 224        Thus, it seems to me that single-stepping won't restore the
 225        float control.  Since SBCL currently doesn't support
 226        single-stepping (as far as I can tell) this is somewhat moot,
 227        but it might be worth either moving this code up or deleting
 228        the single-stepping code entirely.  -- CSR, 2002-07-15 */
 229 #ifdef LISP_FEATURE_LINUX
 230     os_restore_fp_control(context);
 231 #endif
 232
 233     /* On entry %eip points just after the INT3 byte and aims at the
 234      * 'kind' value (eg trap_Cerror). For error-trap and Cerror-trap a
 235      * number of bytes will follow, the first is the length of the byte
 236      * arguments to follow. */
 237     trap = *(unsigned char *)(*os_context_pc_addr(context));
 238     switch (trap) {
 239
 240     case trap_PendingInterrupt:
 241         FSHOW((stderr, "/<trap pending interrupt>\n"));
 242         arch_skip_instruction(context);
 243         interrupt_handle_pending(context);
 244         break;
 245
 246     case trap_Halt:
 247         /* Note: the old CMU CL code tried to save FPU state
 248          * here, and restore it after we do our thing, but there
 249          * seems to be no point in doing that, since we're just
 250          * going to lose(..) anyway. */
 251         fake_foreign_function_call(context);
 252         lose("%%PRIMITIVE HALT called; the party is over.");
 253
 254     case trap_Error:
 255     case trap_Cerror:
 256         FSHOW((stderr, "<trap error/cerror %d>\n", code));
 257         interrupt_internal_error(signal, info, context, code==trap_Cerror);
 258         break;
 259
 260     case trap_Breakpoint:
 261         (char*)(*os_context_pc_addr(context)) -= 1;
 262         handle_breakpoint(signal, info, context);
 263         break;
 264
 265     case trap_FunEndBreakpoint:
 266         (char*)(*os_context_pc_addr(context)) -= 1;
 267         *os_context_pc_addr(context) =
 268             (int)handle_fun_end_breakpoint(signal, info, context);
 269         break;
 270
 271     default:
 272         FSHOW((stderr,"/[C--trap default %d %d %x]\n",
 273                signal, code, context));
 274         interrupt_handle_now(signal, info, context);
 275         break;
 276     }
 277 }
 278
 279 static void
 280 sigill_handler(int signal, siginfo_t *siginfo, void *void_context) {
 281     os_context_t *context = (os_context_t*)void_context;
 282     fake_foreign_function_call(context);
 283     monitor_or_something();
 284 }
 285
 286 void
 287 arch_install_interrupt_handlers()
 288 {
 289     SHOW("entering arch_install_interrupt_handlers()");
 290
 291     /* Note: The old CMU CL code here used sigtrap_handler() to handle
 292      * SIGILL as well as SIGTRAP. I couldn't see any reason to do
 293      * things that way. So, I changed to separate handlers when
 294      * debugging a problem on OpenBSD, where SBCL wasn't catching
 295      * SIGILL properly, but was instead letting the process be
 296      * terminated with an "Illegal instruction" output. If this change
 297      * turns out to break something (maybe breakpoint handling on some
 298      * OS I haven't tested on?) and we have to go back to the old CMU
 299      * CL way, I hope there will at least be a comment to explain
 300      * why.. -- WHN 2001-06-07 */
 301     undoably_install_low_level_interrupt_handler(SIGILL , sigill_handler);
 302     undoably_install_low_level_interrupt_handler(SIGTRAP, sigtrap_handler);
 303
 304     SHOW("returning from arch_install_interrupt_handlers()");
 305 }
 306 \f
 307 /* This is implemented in assembly language and called from C: */
 308 extern lispobj
 309 call_into_lisp(lispobj fun, lispobj *args, int nargs);
 310
 311 /* These functions are an interface to the Lisp call-in facility.
 312  * Since this is C we can know nothing about the calling environment.
 313  * The control stack might be the C stack if called from the monitor
 314  * or the Lisp stack if called as a result of an interrupt or maybe
 315  * even a separate stack. The args are most likely on that stack but
 316  * could be in registers depending on what the compiler likes. So we
 317  * copy the args into a portable vector and let the assembly language
 318  * call-in function figure it out. */
 319 lispobj
 320 funcall0(lispobj function)
 321 {
 322     lispobj *args = NULL;
 323
 324     FSHOW((stderr, "/entering funcall0(0x%lx)\n", (long)function));
 325     return call_into_lisp(function, args, 0);
 326 }
 327 lispobj
 328 funcall1(lispobj function, lispobj arg0)
 329 {
 330     lispobj args[1];
 331     args[0] = arg0;
 332     return call_into_lisp(function, args, 1);
 333 }
 334 lispobj
 335 funcall2(lispobj function, lispobj arg0, lispobj arg1)
 336 {
 337     lispobj args[2];
 338     args[0] = arg0;
 339     args[1] = arg1;
 340     return call_into_lisp(function, args, 2);
 341 }
 342 lispobj
 343 funcall3(lispobj function, lispobj arg0, lispobj arg1, lispobj arg2)
 344 {
 345     lispobj args[3];
 346     args[0] = arg0;
 347     args[1] = arg1;
 348     args[2] = arg2;
 349     return call_into_lisp(function, args, 3);
 350 }