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/* GDB Simulator wrapper for Or1ksim, the OpenRISC architectural simulator Copyright 1988-2008, Free Software Foundation, Inc. Copyright (C) 2010 Embecosm Limited Contributor Jeremy Bennett <jeremy.bennett@embecosm.com> This file is part of GDB. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ /*---------------------------------------------------------------------------*/ /* This is a wrapper for Or1ksim, suitable for use as a GDB simulator. The code tries to follow the GDB coding style. Commenting is Doxygen compatible. */ /*---------------------------------------------------------------------------*/ #include <errno.h> #include <stdlib.h> #include <stdio.h> #include <signal.h> #include <string.h> #include <sys/socket.h> #include <sys/types.h> #include <sys/un.h> #include <unistd.h> #include "ansidecl.h" #include "gdb/callback.h" #include "gdb/remote-sim.h" #include "sim-utils.h" #include "targ-vals.h" #include "or1ksim.h" #include "or32sim.h" /* Define this to turn on debug messages */ /* #define OR32_SIM_DEBUG */ /* ------------------------------------------------------------------------- */ /*!Create a fully initialized simulator instance. This function is called when the simulator is selected from the gdb command line. While the simulator configuration can be parameterized by (in decreasing precedence) argv's SIM-OPTION, argv's TARGET-PROGRAM and the abfd argument, the successful creation of the simulator shall not dependent on the presence of any of these arguments/options. For a hardware simulator the created simulator shall be sufficiently initialized to handle, without restrictions any client requests (including memory reads/writes, register fetch/stores and a resume). For a process simulator, the process is not created until a call to sim_create_inferior. We do the following on a first call. - parse the options - @todo Eventually we should use the option parser built into the GDB simulator (see common/sim-options.h). However since this is minimally documented, and we have only the one option, for now we do it ourselves. @note We seem to capable of being called twice. We use the static "global_sd" variable to keep track of this. Second and subsequent calls do nothing, but return the previously opened simulator description. @param[in] kind Specifies how the simulator shall be used. Currently there are only two kinds: stand-alone and debug. @param[in] callback Specifies a standard host callback (defined in callback.h). @param[in] abfd When non NULL, designates a target program. The program is not loaded. @param[in] argv A standard ARGV pointer such as that passed from the command line. The syntax of the argument list is is assumed to be ``SIM-PROG { SIM-OPTION } [ TARGET-PROGRAM { TARGET-OPTION } ]''. The trailing TARGET-PROGRAM and args are only valid for a stand-alone simulator. The argument list is null terminated! @return On success, the result is a non NULL descriptor that shall be passed to the other sim_foo functions. */ /* ------------------------------------------------------------------------- */ SIM_DESC sim_open (SIM_OPEN_KIND kind, struct host_callback_struct *callback, struct bfd *abfd, char *argv[]) { /*!A global record of the simulator description */ static SIM_DESC static_sd = NULL; #ifdef OR32_SIM_DEBUG printf ("sim_open called\n", (int) kind); #endif /* If static_sd is not yet allocated, we allocate it and mark the simulator as not yet open. This is the only time we can process any custom arguments and only time we initialize the simulator. */ if (NULL == static_sd) { int local_argc; /* Our local argv with extra args */ char **local_argv; int argc; /* How many args originally */ int i; /* For local argv */ int mem_defined_p = 0; /* Have we requested a memory size? */ int res; /* Result of initialization */ static_sd = (SIM_DESC) malloc (sizeof (*static_sd)); static_sd->sim_open = 0; /* Count the number of arguments and see if we have specified either a config file or a memory size. */ for (argc = 1; NULL != argv[argc]; argc++) { #ifdef OR32_SIM_DEBUG printf ("argv[%d] = %s\n", argc, argv[argc]); #endif if ((0 == strcmp (argv[argc], "-f")) || (0 == strcmp (argv[argc], "-file")) || (0 == strcmp (argv[argc], "-m")) || (0 == strcmp (argv[argc], "-memory"))) { mem_defined_p = 1; } } /* If we have no memory defined, we give it a default 8MB. We also always run quiet. So we must define our own argument vector */ local_argc = mem_defined_p ? argc + 1 : argc + 3; local_argv = malloc ((local_argc + 1) * sizeof (char *)); for (i = 0 ; i < argc; i++) { local_argv[i] = argv[i]; } local_argv[i++] = "--quiet"; if (!mem_defined_p) { local_argv[i++] = "--memory"; local_argv[i++] = "8M"; } local_argv[i] = NULL; /* Try to initialize, then we can free the local argument vector. If we fail to initialize return NULL to indicate that failure. */ res = or1ksim_init (local_argc, local_argv, NULL, NULL, NULL); free (local_argv); if (res) { return NULL; /* Failure */ } } /* We have either initialized a new simulator, or already have an intialized simulator. Populate the descriptor and stall the processor, the return the descriptor. */ static_sd->callback = callback; static_sd->is_debug = (kind == SIM_OPEN_DEBUG); static_sd->myname = (char *)xstrdup (argv[0]); static_sd->sim_open = 1; static_sd->last_reason = sim_running; static_sd->last_rc = TARGET_SIGNAL_NONE; static_sd->entry_point = OR32_RESET_EXCEPTION; static_sd->resume_npc = OR32_RESET_EXCEPTION; or1ksim_set_stall_state (0); return static_sd; } /* sim_open () */ /* ------------------------------------------------------------------------- */ /*!Destroy a simulator instance. We never actually close the simulator, because we have no way to reinitialize it. Instead we just stall the processor and mark it closed. @param[in] sd Simulation descriptor from sim_open (). @param[in] quitting Non-zero if we cannot hang on errors. */ /* ------------------------------------------------------------------------- */ void sim_close (SIM_DESC sd, int quitting) { #ifdef OR32_SIM_DEBUG printf ("sim_close called\n"); #endif if (NULL == sd) { fprintf (stderr, "Warning: Attempt to close non-open simulation: ignored.\n"); } else { free (sd->myname); sd->sim_open = 0; or1ksim_set_stall_state (0); } } /* sim_close () */ /* ------------------------------------------------------------------------- */ /*!Load program PROG into the simulators memory. Hardware simulator: Normally, each program section is written into memory according to that sections LMA using physical (direct) addressing. The exception being systems, such as PPC/CHRP, which support more complicated program loaders. A call to this function should not effect the state of the processor registers. Multiple calls to this function are permitted and have an accumulative effect. Process simulator: Calls to this function may be ignored. @todo Most hardware simulators load the image at the VMA using virtual addressing. @todo For some hardware targets, before a loaded program can be executed, it requires the manipulation of VM registers and tables. Such manipulation should probably (?) occure in sim_create_inferior (). @param[in] sd Simulation descriptor from sim_open (). @param[in] prog The name of the program @param[in] abfd If non-NULL, the BFD for the file has already been opened. @param[in] from_tty Not sure what this does. Probably indicates this is a command line load? Anyway we don't use it. @return A return code indicating success. */ /* ------------------------------------------------------------------------- */ SIM_RC sim_load (SIM_DESC sd, char *prog, struct bfd *abfd, int from_tty) { bfd *prog_bfd; #ifdef OR32_SIM_DEBUG printf ("sim_load called\n"); #endif /* Use the built in loader, which will in turn use our write function. */ prog_bfd = sim_load_file (sd, sd->myname, sd->callback, prog, abfd, sd->is_debug, 0, sim_write); if (NULL == prog_bfd) { return SIM_RC_FAIL; } /* If the BFD was not already open, then close the loaded program. */ if (NULL == abfd) { bfd_close (prog_bfd); } return SIM_RC_OK; } /* sim_load () */ /* ------------------------------------------------------------------------- */ /*!Prepare to run the simulated program. Hardware simulator: This function shall initialize the processor registers to a known value. The program counter and possibly stack pointer shall be set using information obtained from ABFD (or hardware reset defaults). ARGV and ENV, dependant on the target ABI, may be written to memory. Process simulator: After a call to this function, a new process instance shall exist. The TEXT, DATA, BSS and stack regions shall all be initialized, ARGV and ENV shall be written to process address space (according to the applicable ABI) and the program counter and stack pointer set accordingly. ABFD, if not NULL, provides initial processor state information. ARGV and ENV, if non NULL, are NULL terminated lists of pointers. We perform the following steps: - stall the processor - set the entry point to the entry point in the BFD, or the reset vector if the BFD is not available. - set the resumption NPC to the reset vector. We always do this, to ensure the library is initialized. @param[in] sd Simulation descriptor from sim_open (). @param[in] abfd If non-NULL provides initial processor state information. @param[in] argv Vector of arguments to the program. We don't use this @param[in] env Vector of environment data. We don't use this. @return A return code indicating success. */ /* ------------------------------------------------------------------------- */ SIM_RC sim_create_inferior (SIM_DESC sd, struct bfd *abfd, char **argv ATTRIBUTE_UNUSED, char **env ATTRIBUTE_UNUSED) { #ifdef OR32_SIM_DEBUG printf ("sim_create_inferior called\n"); #endif or1ksim_set_stall_state (1); sd->entry_point = (NULL == abfd) ? OR32_RESET_EXCEPTION : bfd_get_start_address (abfd); sd->resume_npc = OR32_RESET_EXCEPTION; return SIM_RC_OK; } /* sim_create_inferior () */ /* ------------------------------------------------------------------------- */ /*!Fetch bytes from the simulated program's memory. @param[in] sd Simulation descriptor from sim_open (). We don't use this. @param[in] mem The address in memory to fetch from. @param[out] buf Where to put the read data @param[in] len Number of bytes to fetch @return Number of bytes read, or zero if error. */ /* ------------------------------------------------------------------------- */ int sim_read (SIM_DESC sd ATTRIBUTE_UNUSED, SIM_ADDR mem, unsigned char *buf, int len) { int res = or1ksim_read_mem (mem, buf, len); #ifdef OR32_SIM_DEBUG printf ("Reading %d bytes from %08p\n", len, (void *) mem); #endif return res; } /* sim_read () */ /* ------------------------------------------------------------------------- */ /*!Store bytes to the simulated program's memory. @param[in] sd Simulation descriptor from sim_open (). We don't use this. @param[in] mem The address in memory to write to. @param[in] buf The data to write @param[in] len Number of bytes to write @return Number of byte written, or zero if error. */ /* ------------------------------------------------------------------------- */ int sim_write (SIM_DESC sd ATTRIBUTE_UNUSED, SIM_ADDR mem, const unsigned char *buf, int len) { #ifdef OR32_SIM_DEBUG printf ("Writing %d bytes to %08p\n", len, (void *) mem); #endif return or1ksim_write_mem ((unsigned int) mem, buf, len); } /* sim_write () */ /* ------------------------------------------------------------------------- */ /*!Fetch a register from the simulation We get the register back as a 32-bit value. However we must convert it to a character array <em>in target endian order</em>. The exception is if the register is the NPC, which is only written just before resumption, to avoid pipeline confusion. It is fetched from the SD. @param[in] sd Simulation descriptor from sim_open (). We don't use this. @param[in] regno The register to fetch @param[out] buf Buffer of length bytes to store the result. Data is only transferred if length matches the register length (the actual register size is still returned). @param[in] len Size of buf, which should match the size of the register. @return The actual size of the register, or zero if regno is not applicable. Legacy implementations return -1. /* ------------------------------------------------------------------------- */ int sim_fetch_register (SIM_DESC sd, int regno, unsigned char *buf, int len) { unsigned long int regval; int res; #ifdef OR32_SIM_DEBUG printf ("sim_fetch_register (regno=%d) called\n", regno); #endif if (4 != len) { fprintf (stderr, "Invalid register length %d\n", len); return 0; } if (OR32_NPC_REGNUM == regno) { regval = sd->resume_npc; res = 4; } else { int res = or1ksim_read_reg (regno, ®val) ? 4 : 0; } /* Convert to target (big) endian */ if (res) { buf[0] = (regval >> 24) & 0xff; buf[1] = (regval >> 16) & 0xff; buf[2] = (regval >> 8) & 0xff; buf[3] = regval & 0xff; return 4; /* Success */ } else { return 0; /* Failure */ } } /* sim_fetch_register () */ /* ------------------------------------------------------------------------- */ /*!Store a register to the simulation We write the register back as a 32-bit value. However we must convert it from a character array <em>in target endian order</em>. The exception is if the register is the NPC, which is only written just before resumption, to avoid pipeline confusion. It is saved in the SD. @param[in] sd Simulation descriptor from sim_open (). We don't use this. @param[in] regno The register to store @param[in] buf Buffer of length bytes with the data to store. Data is only transferred if length matches the register length (the actual register size is still returned). @param[in] len Size of buf, which should match the size of the register. @return The actual size of the register, or zero if regno is not applicable. Legacy implementations return -1. /* ------------------------------------------------------------------------- */ int sim_store_register (SIM_DESC sd, int regno, unsigned char *buf, int len) { unsigned int regval; #ifdef OR32_SIM_DEBUG printf ("sim_store_register (regno=%d\n) called\n", regno); #endif if (4 != len) { fprintf (stderr, "Invalid register length %d\n", len); return 0; } /* Convert from target (big) endian */ regval = (((unsigned int) buf[0]) << 24) | (((unsigned int) buf[1]) << 16) | (((unsigned int) buf[2]) << 8) | (((unsigned int) buf[3]) ); #ifdef OR32_SIM_DEBUG printf ("Writing register 0x%02x, value 0x%08x\n", regno, regval); #endif if (OR32_NPC_REGNUM == regno) { sd->resume_npc = regval; return 4; /* Reg length in bytes */ } else { return or1ksim_write_reg (regno, regval) ? 4 : 0; } } /* sim_store_register () */ /* ------------------------------------------------------------------------- */ /* Print whatever statistics the simulator has collected. @param[in] sd Simulation descriptor from sim_open (). We don't use this. @param[in] verbose Currently unused, and should always be zero. */ /* ------------------------------------------------------------------------- */ void sim_info (SIM_DESC sd ATTRIBUTE_UNUSED, int verbose ATTRIBUTE_UNUSED) { } /* sim_info () */ /* ------------------------------------------------------------------------- */ /*!Run (or resume) the simulated program. Hardware simulator: If the SIGRC value returned by sim_stop_reason() is passed back to the simulator via siggnal then the hardware simulator shall correctly deliver the hardware event indicated by that signal. If a value of zero is passed in then the simulation will continue as if there were no outstanding signal. The effect of any other siggnal value is is implementation dependant. Process simulator: If SIGRC is non-zero then the corresponding signal is delivered to the simulated program and execution is then continued. A zero SIGRC value indicates that the program should continue as normal. We carry out the following - Clear the debug reason register - Clear watchpoing break generation in debug mode register 2 - Set the debug unit to handle TRAP exceptions - If stepping, set the single step trigger in debug mode register 1 - Write the resume_npc if it differs from the actual NPC. - Unstall the processor - Run the processor. On execution completion, we determine the reason for the halt. If it is a breakpoint, we mark the resumption NPC to be the PPC (so we redo the NPC location). @param[in] sd Simulation descriptor from sim_open (). @param[in] step When non-zero indicates that only a single simulator cycle should be emulated. @param[in] siggnal If non-zero is a (HOST) SIGRC value indicating the type of event (hardware interrupt, signal) to be delivered to the simulated program. */ /* ------------------------------------------------------------------------- */ void sim_resume (SIM_DESC sd, int step, int siggnal) { unsigned long int npc; /* Next Program Counter */ unsigned long int drr; /* Debug Reason Register */ unsigned long int dsr; /* Debug Stop Register */ unsigned long int dmr1; /* Debug Mode Register 1*/ unsigned long int dmr2; /* Debug Mode Register 2*/ unsigned long int retval; /* Return value on Or1ksim exit */ unsigned long int cycles; /* Length of run in cycles */ int res; /* Result of a run. */ #ifdef OR32_SIM_DEBUG printf ("sim_resume called\n"); #endif /* Clear Debug Reason Register and watchpoint break generation in Debug Mode Register 2 */ (void) or1ksim_write_spr (OR32_SPR_DRR, 0); (void) or1ksim_read_spr (OR32_SPR_DMR2, &dmr2); dmr2 &= ~OR32_SPR_DMR2_WGB; (void) or1ksim_write_spr (OR32_SPR_DMR2, dmr2); /* Set debug unit to handle TRAP exceptions */ (void) or1ksim_read_spr (OR32_SPR_DSR, &dsr); dsr |= OR32_SPR_DSR_TE; (void) or1ksim_write_spr (OR32_SPR_DSR, dsr); /* Set the single step trigger in Debug Mode Register 1 if we are stepping. Otherwise clear it! */ if (step) { (void) or1ksim_read_spr (OR32_SPR_DMR1, &dmr1); dmr1 |= OR32_SPR_DMR1_ST; (void) or1ksim_write_spr (OR32_SPR_DMR1, dmr1); } else { (void) or1ksim_read_spr (OR32_SPR_DMR1, &dmr1); dmr1 &= ~OR32_SPR_DMR1_ST; (void) or1ksim_write_spr (OR32_SPR_DMR1, dmr1); } /* Set the NPC if it has changed */ (void) or1ksim_read_reg (OR32_NPC_REGNUM, &npc); #ifdef OR32_SIM_DEBUG printf (" npc = 0x%08lx, resume_npc = 0x%08lx\n", npc, sd->resume_npc); #endif if (npc != sd->resume_npc) { (void) or1ksim_write_reg (OR32_NPC_REGNUM, sd->resume_npc); } /* Set a time point */ or1ksim_set_time_point (); /* Unstall and run */ or1ksim_set_stall_state (0); res = or1ksim_run (-1.0); /* Determine the reason for stopping. If we hit a breakpoint, then the resumption NPC must be set to the PPC to allow re-execution of the trapped instruction. */ switch (res) { case OR1KSIM_RC_HALTED: #ifdef OR32_SIM_DEBUG (void) or1ksim_read_reg (OR32_NPC_REGNUM, &npc); printf (" execution halted at 0x%08lx.\n", npc); #endif sd->last_reason = sim_exited; (void) or1ksim_read_reg (OR32_FIRST_ARG_REGNUM, &retval); sd->last_rc = (unsigned int) retval; sd->resume_npc = OR32_RESET_EXCEPTION; cycles = (long int) (or1ksim_get_time_period () * (double) or1ksim_clock_rate()); break; case OR1KSIM_RC_BRKPT: #ifdef OR32_SIM_DEBUG printf (" execution hit breakpoint.\n"); #endif sd->last_reason = sim_stopped; sd->last_rc = TARGET_SIGNAL_TRAP; /* This could have been a breakpoint or single step. */ if (step) { (void) or1ksim_read_reg (OR32_NPC_REGNUM, &(sd->resume_npc)); } else { (void) or1ksim_read_reg (OR32_PPC_REGNUM, &(sd->resume_npc)); } break; case OR1KSIM_RC_OK: /* Should not happen */ fprintf (stderr, "Ooops. Didn't expect OK return from Or1ksim.\n"); sd->last_reason = sim_running; /* Should trigger an error! */ sd->last_rc = TARGET_SIGNAL_NONE; (void) or1ksim_read_reg (OR32_NPC_REGNUM, &(sd->resume_npc)); break; } } /* sim_resume () */ /* ------------------------------------------------------------------------- */ /*!Asynchronous request to stop the simulation. @param[in] sd Simulation descriptor from sim_open (). We don't use this. @return Non-zero indicates that the simulator is able to handle the request. */ /* ------------------------------------------------------------------------- */ int sim_stop (SIM_DESC sd ATTRIBUTE_UNUSED) { #ifdef OR32_SIM_DEBUG printf ("sim_stop called\n"); #endif return 0; /* We don't support this */ } /* sim_stop () */ /* ------------------------------------------------------------------------- */ /*!Fetch the REASON why the program stopped. The reason enumeration indicates why: - sim_exited: The program has terminated. sigrc indicates the target dependant exit status. - sim_stopped: The program has stopped. sigrc uses the host's signal numbering as a way of identifying the reaon: program interrupted by user via a sim_stop request (SIGINT); a breakpoint instruction (SIGTRAP); a completed single step (SIGTRAP); an internal error condition (SIGABRT); an illegal instruction (SIGILL); Access to an undefined memory region (SIGSEGV); Mis-aligned memory access (SIGBUS). For some signals information in addition to the signal number may be retained by the simulator (e.g. offending address), that information is not directly accessable via this interface. - sim_signalled: The program has been terminated by a signal. The simulator has encountered target code that causes the the program to exit with signal sigrc. - sim_running: - sim_polling: The return of one of these values indicates a problem internal to the simulator. @param[in] sd Simulation descriptor from sim_open (). @param[out] reason The reason for stopping @param[out] sigrc Supplementary information for some values of reason. */ /* ------------------------------------------------------------------------- */ void sim_stop_reason (SIM_DESC sd, enum sim_stop *reason, int *sigrc) { *reason = sd->last_reason; *sigrc = sd->last_rc; } /* sim_stop_reason () */ /* ------------------------------------------------------------------------- */ /* Passthru for other commands that the simulator might support. Simulators should be prepared to deal with any combination of NULL or empty command. This implementation currently does nothing. @param[in] sd Simulation descriptor from sim_open (). We don't use this. @param[in] cmd The command to pass through. */ /* ------------------------------------------------------------------------- */ void sim_do_command (SIM_DESC sd ATTRIBUTE_UNUSED, char *cmd ATTRIBUTE_UNUSED) { #ifdef OR32_SIM_DEBUG printf ("sim_do_command called\n"); #endif } /* sim_do_command () */ /* ------------------------------------------------------------------------- */ /* Set the default host_callback_struct @note Deprecated, but implemented, since it is still required for linking. This implementation currently does nothing. @param[in] ptr The host_callback_struct pointer. Unused here. */ /* ------------------------------------------------------------------------- */ void sim_set_callbacks (struct host_callback_struct *ptr ATTRIBUTE_UNUSED) { #ifdef OR32_SIM_DEBUG printf ("sim_set_callbacks called\n"); #endif } /* sim_set_callbacks () */ /* ------------------------------------------------------------------------- */ /* Set the size of the simulator memory array. @note Deprecated, but implemented, since it is still required for linking. This implementation currently does nothing. @param[in] size The memory size to use. Unused here. */ /* ------------------------------------------------------------------------- */ void sim_size (int size ATTRIBUTE_UNUSED) { #ifdef OR32_SIM_DEBUG printf ("sim_size called\n"); #endif } /* sim_size () */ /* ------------------------------------------------------------------------- */ /* Single step the simulator with tracing enabled. @note Deprecated, but implemented, since it is still required for linking. This implementation currently does nothing. @param[in] sd The simulator description struct. Unused here. */ /* ------------------------------------------------------------------------- */ void sim_trace (SIM_DESC sd ATTRIBUTE_UNUSED) { #ifdef OR32_SIM_DEBUG printf ("sim_trace called\n"); #endif } /* sim_trace () */