include/sim/sim.h

   1 /* This file defines the interface between the simulator and gdb.
   2
   3    Copyright (C) 1993-2022 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #ifndef SIM_SIM_H
  21 #define SIM_SIM_H 1
  22
  23 #include <stdint.h>
  24
  25 #ifdef __cplusplus
  26 extern "C" {
  27 #endif
  28
  29 /* This file is used when building stand-alone simulators, so isolate this
  30    file from gdb.  */
  31
  32 typedef unsigned int SIM_ADDR;
  33
  34
  35 /* Semi-opaque type used as result of sim_open and passed back to all
  36    other routines.  "desc" is short for "descriptor".
  37    It is up to each simulator to define `sim_state'.  */
  38
  39 typedef struct sim_state *SIM_DESC;
  40
  41
  42 /* Values for `kind' arg to sim_open.  */
  43
  44 typedef enum {
  45   SIM_OPEN_STANDALONE, /* simulator used standalone (run.c) */
  46   SIM_OPEN_DEBUG       /* simulator used by debugger (gdb) */
  47 } SIM_OPEN_KIND;
  48
  49
  50 /* Return codes from various functions.  */
  51
  52 typedef enum {
  53   SIM_RC_FAIL = 0,
  54   SIM_RC_OK = 1
  55 } SIM_RC;
  56
  57
  58 /* Some structs, as opaque types.  */
  59
  60 struct bfd;
  61 struct host_callback_struct;
  62
  63
  64 /* Main simulator entry points.  */
  65
  66
  67 /* Create a fully initialized simulator instance.
  68
  69    (This function is called when the simulator is selected from the
  70    gdb command line.)
  71
  72    KIND specifies how the simulator shall be used.  Currently there
  73    are only two kinds: stand-alone and debug.
  74
  75    CALLBACK specifies a standard host callback (defined in callback.h).
  76
  77    ABFD, when non NULL, designates a target program.  The program is
  78    not loaded.
  79
  80    ARGV is a standard ARGV pointer such as that passed from the
  81    command line.  The syntax of the argument list is is assumed to be
  82    ``SIM-PROG { SIM-OPTION } [ TARGET-PROGRAM { TARGET-OPTION } ]''.
  83    The trailing TARGET-PROGRAM and args are only valid for a
  84    stand-alone simulator.
  85
  86    On success, the result is a non NULL descriptor that shall be
  87    passed to the other sim_foo functions.  While the simulator
  88    configuration can be parameterized by (in decreasing precedence)
  89    ARGV's SIM-OPTION, ARGV's TARGET-PROGRAM and the ABFD argument, the
  90    successful creation of the simulator shall not dependent on the
  91    presence of any of these arguments/options.
  92
  93    Hardware simulator: The created simulator shall be sufficiently
  94    initialized to handle, with out restrictions any client requests
  95    (including memory reads/writes, register fetch/stores and a
  96    resume).
  97
  98    Process simulator: that process is not created until a call to
  99    sim_create_inferior.  FIXME: What should the state of the simulator
 100    be? */
 101
 102 SIM_DESC sim_open (SIM_OPEN_KIND kind, struct host_callback_struct *callback,
 103                    struct bfd *abfd, char * const *argv);
 104
 105
 106 /* Destory a simulator instance.
 107
 108    QUITTING is non-zero if we cannot hang on errors.
 109
 110    This may involve freeing target memory and closing any open files
 111    and mmap'd areas.  You cannot assume sim_kill has already been
 112    called. */
 113
 114 void sim_close (SIM_DESC sd, int quitting);
 115
 116
 117 /* Load program PROG into the simulators memory.
 118
 119    If ABFD is non-NULL, the bfd for the file has already been opened.
 120    The result is a return code indicating success.
 121
 122    Hardware simulator: Normally, each program section is written into
 123    memory according to that sections LMA using physical (direct)
 124    addressing.  The exception being systems, such as PPC/CHRP, which
 125    support more complicated program loaders.  A call to this function
 126    should not effect the state of the processor registers.  Multiple
 127    calls to this function are permitted and have an accumulative
 128    effect.
 129
 130    Process simulator: Calls to this function may be ignored.
 131
 132    FIXME: Most hardware simulators load the image at the VMA using
 133    virtual addressing.
 134
 135    FIXME: For some hardware targets, before a loaded program can be
 136    executed, it requires the manipulation of VM registers and tables.
 137    Such manipulation should probably (?) occure in
 138    sim_create_inferior. */
 139
 140 SIM_RC sim_load (SIM_DESC sd, const char *prog, struct bfd *abfd, int from_tty);
 141
 142
 143 /* Prepare to run the simulated program.
 144
 145    ABFD, if not NULL, provides initial processor state information.
 146    ARGV and ENV, if non NULL, are NULL terminated lists of pointers.
 147
 148    Hardware simulator: This function shall initialize the processor
 149    registers to a known value.  The program counter and possibly stack
 150    pointer shall be set using information obtained from ABFD (or
 151    hardware reset defaults).  ARGV and ENV, dependant on the target
 152    ABI, may be written to memory.
 153
 154    Process simulator: After a call to this function, a new process
 155    instance shall exist. The TEXT, DATA, BSS and stack regions shall
 156    all be initialized, ARGV and ENV shall be written to process
 157    address space (according to the applicable ABI) and the program
 158    counter and stack pointer set accordingly. */
 159
 160 SIM_RC sim_create_inferior (SIM_DESC sd, struct bfd *abfd,
 161                             char * const *argv, char * const *env);
 162
 163
 164 /* Fetch LENGTH bytes of the simulated program's memory.  Start fetch
 165    at virtual address MEM and store in BUF.  Result is number of bytes
 166    read, or zero if error.  */
 167
 168 uint64_t sim_read (SIM_DESC sd, uint64_t mem, void *buf, uint64_t length);
 169
 170
 171 /* Store LENGTH bytes from BUF into the simulated program's
 172    memory. Store bytes starting at virtual address MEM. Result is
 173    number of bytes write, or zero if error.  */
 174
 175 uint64_t sim_write (SIM_DESC sd, uint64_t mem, const void *buf, uint64_t length);
 176
 177
 178 /* Fetch register REGNO storing its raw (target endian) value in the
 179    LENGTH byte buffer BUF.  Return the actual size of the register or
 180    zero if REGNO is not applicable.
 181
 182    Legacy implementations ignore LENGTH and always return -1.
 183
 184    If LENGTH does not match the size of REGNO no data is transfered
 185    (the actual register size is still returned). */
 186
 187 int sim_fetch_register (SIM_DESC sd, int regno, void *buf, int length);
 188
 189
 190 /* Store register REGNO from the raw (target endian) value in BUF.
 191
 192    Return the actual size of the register, any size not equal to
 193    LENGTH indicates the register was not updated correctly.
 194
 195    Return a LENGTH of -1 to indicate the register was not updated
 196    and an error has occurred.
 197
 198    Return a LENGTH of 0 to indicate the register was not updated
 199    but no error has occurred. */
 200
 201 int sim_store_register (SIM_DESC sd, int regno, const void *buf, int length);
 202
 203
 204 /* Print whatever statistics the simulator has collected.
 205
 206    VERBOSE is currently unused and must always be zero.  */
 207
 208 void sim_info (SIM_DESC sd, int verbose);
 209
 210
 211 /* Return a memory map in XML format.
 212
 213    The caller must free the returned string.
 214
 215    For details on the format, see GDB's Memory Map Format documentation.  */
 216
 217 char *sim_memory_map (SIM_DESC sd);
 218
 219
 220 /* Run (or resume) the simulated program.
 221
 222    STEP, when non-zero indicates that only a single simulator cycle
 223    should be emulated.
 224
 225    SIGGNAL, if non-zero is a (HOST) SIGRC value indicating the type of
 226    event (hardware interrupt, signal) to be delivered to the simulated
 227    program.
 228
 229    Hardware simulator: If the SIGRC value returned by
 230    sim_stop_reason() is passed back to the simulator via SIGGNAL then
 231    the hardware simulator shall correctly deliver the hardware event
 232    indicated by that signal.  If a value of zero is passed in then the
 233    simulation will continue as if there were no outstanding signal.
 234    The effect of any other SIGGNAL value is is implementation
 235    dependant.
 236
 237    Process simulator: If SIGRC is non-zero then the corresponding
 238    signal is delivered to the simulated program and execution is then
 239    continued.  A zero SIGRC value indicates that the program should
 240    continue as normal. */
 241
 242 void sim_resume (SIM_DESC sd, int step, int siggnal);
 243
 244
 245 /* Asynchronous request to stop the simulation.
 246    A nonzero return indicates that the simulator is able to handle
 247    the request */
 248
 249 int sim_stop (SIM_DESC sd);
 250
 251
 252 /* Fetch the REASON why the program stopped.
 253
 254    SIM_EXITED: The program has terminated. SIGRC indicates the target
 255    dependant exit status.
 256
 257    SIM_STOPPED: The program has stopped.  SIGRC uses the host's signal
 258    numbering as a way of identifying the reaon: program interrupted by
 259    user via a sim_stop request (SIGINT); a breakpoint instruction
 260    (SIGTRAP); a completed single step (SIGTRAP); an internal error
 261    condition (SIGABRT); an illegal instruction (SIGILL); Access to an
 262    undefined memory region (SIGSEGV); Mis-aligned memory access
 263    (SIGBUS).  For some signals information in addition to the signal
 264    number may be retained by the simulator (e.g. offending address),
 265    that information is not directly accessable via this interface.
 266
 267    SIM_SIGNALLED: The program has been terminated by a signal. The
 268    simulator has encountered target code that causes the program
 269    to exit with signal SIGRC.
 270
 271    SIM_RUNNING, SIM_POLLING: The return of one of these values
 272    indicates a problem internal to the simulator. */
 273
 274 enum sim_stop { sim_running, sim_polling, sim_exited, sim_stopped, sim_signalled };
 275
 276 void sim_stop_reason (SIM_DESC sd, enum sim_stop *reason, int *sigrc);
 277
 278
 279 /* Passthru for other commands that the simulator might support.
 280    Simulators should be prepared to deal with any combination of NULL
 281    or empty CMD. */
 282
 283 void sim_do_command (SIM_DESC sd, const char *cmd);
 284
 285 /* Complete a command based on the available sim commands.  Returns an
 286    array of possible matches.  */
 287
 288 char **sim_complete_command (SIM_DESC sd, const char *text, const char *word);
 289
 290 #ifdef __cplusplus
 291 }
 292 #endif
 293
 294 #endif /* !defined (SIM_SIM_H) */