/*      $OpenBSD: pmon.c,v 1.4 2010/02/16 21:29:54 miod Exp $   */

/*
* Copyright (c) 2009 Miodrag Vallat.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/cpu.h>
#include <sys/proc.h>

#include <mips/cpuregs.h>
#include <mips/pmon/pmon.h>

int     pmon_argc;
int32_t *pmon_argv;
int32_t *pmon_envp;

void
pmon_init(int32_t argc, int32_t argv, int32_t envp, int32_t callvec)
{
       pmon_callvec = callvec;

       pmon_argc = argc;
       /* sign extend pointers */
       pmon_argv = (int32_t *)(vaddr_t)argv;
       pmon_envp = (int32_t *)(vaddr_t)envp;
}

const char *
pmon_getarg(const int argno)
{
       if (argno < 0 || argno >= pmon_argc)
               return NULL;

       return (const char *)(vaddr_t)pmon_argv[argno];
}

const char *
pmon_getenv(const char *var)
{
       int32_t *envptr = pmon_envp;
       const char *envstr;
       size_t varlen;

       if (envptr == NULL)
               return NULL;

       varlen = strlen(var);
       while (*envptr != 0) {
               envstr = (const char *)(vaddr_t)*envptr;
               /*
                * There is a PMON2000 bug, at least on Lemote Yeeloong,
                * which causes it to override part of the environment
                * pointers array with the environment data itself.
                *
                * This only happens on cold boot, and if the BSD kernel
                * is loaded without symbols (i.e. no option -k passed
                * to the boot command).
                *
                * Until a suitable workaround is found or the bug is
                * fixed, ignore broken environment information and
                * tell the user (in case this prevents us from finding
                * important information).
                */
               if ((vaddr_t)envstr < (vaddr_t)MIPS_KSEG1_START ||
                   (vaddr_t)envstr >= (vaddr_t)MIPS_KSEG2_START) {
                       printf("WARNING! CORRUPTED ENVIRONMENT!\n");
                       printf("Unable to search for %s.\n", var);
#ifdef _STANDALONE
                       printf("If boot fails, power-cycle the machine.\n");
#else
                       printf("If the kernel fails to identify the system"
                           " type, please boot it again with `-k' option.\n");
#endif

                       /* terminate environment for further calls */
                       *envptr = 0;
                       break;
               }
               if (strncmp(envstr, var, varlen) == 0 &&
                   envstr[varlen] == '=')
                       return envstr + varlen + 1;
               envptr++;
       }

       return NULL;
}