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      1 /*	$OpenBSD: pmon.c,v 1.4 2010/02/16 21:29:54 miod Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2009 Miodrag Vallat.
      5  *
      6  * Permission to use, copy, modify, and distribute this software for any
      7  * purpose with or without fee is hereby granted, provided that the above
      8  * copyright notice and this permission notice appear in all copies.
      9  *
     10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
     11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
     12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
     13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
     14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
     15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
     16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
     17  */
     18 
     19 #include <sys/param.h>
     20 #include <sys/systm.h>
     21 #include <sys/cpu.h>
     22 #include <sys/proc.h>
     23 
     24 #include <mips/cpuregs.h>
     25 #include <mips/pmon/pmon.h>
     26 
     27 int	pmon_argc;
     28 int32_t	*pmon_argv;
     29 int32_t	*pmon_envp;
     30 
     31 void
     32 pmon_init(int32_t argc, int32_t argv, int32_t envp, int32_t callvec)
     33 {
     34 	pmon_callvec = callvec;
     35 
     36 	pmon_argc = argc;
     37 	/* sign extend pointers */
     38 	pmon_argv = (int32_t *)(vaddr_t)argv;
     39 	pmon_envp = (int32_t *)(vaddr_t)envp;
     40 }
     41 
     42 const char *
     43 pmon_getarg(const int argno)
     44 {
     45 	if (argno < 0 || argno >= pmon_argc)
     46 		return NULL;
     47 
     48 	return (const char *)(vaddr_t)pmon_argv[argno];
     49 }
     50 
     51 const char *
     52 pmon_getenv(const char *var)
     53 {
     54 	int32_t *envptr = pmon_envp;
     55 	const char *envstr;
     56 	size_t varlen;
     57 
     58 	if (envptr == NULL)
     59 		return NULL;
     60 
     61 	varlen = strlen(var);
     62 	while (*envptr != 0) {
     63 		envstr = (const char *)(vaddr_t)*envptr;
     64 		/*
     65 		 * There is a PMON2000 bug, at least on Lemote Yeeloong,
     66 		 * which causes it to override part of the environment
     67 		 * pointers array with the environment data itself.
     68 		 *
     69 		 * This only happens on cold boot, and if the BSD kernel
     70 		 * is loaded without symbols (i.e. no option -k passed
     71 		 * to the boot command).
     72 		 *
     73 		 * Until a suitable workaround is found or the bug is
     74 		 * fixed, ignore broken environment information and
     75 		 * tell the user (in case this prevents us from finding
     76 		 * important information).
     77 		 */
     78 		if ((vaddr_t)envstr < (vaddr_t)MIPS_KSEG1_START ||
     79 		    (vaddr_t)envstr >= (vaddr_t)MIPS_KSEG2_START) {
     80 			printf("WARNING! CORRUPTED ENVIRONMENT!\n");
     81 			printf("Unable to search for %s.\n", var);
     82 #ifdef _STANDALONE
     83 			printf("If boot fails, power-cycle the machine.\n");
     84 #else
     85 			printf("If the kernel fails to identify the system"
     86 			    " type, please boot it again with `-k' option.\n");
     87 #endif
     88 
     89 			/* terminate environment for further calls */
     90 			*envptr = 0;
     91 			break;
     92 		}
     93 		if (strncmp(envstr, var, varlen) == 0 &&
     94 		    envstr[varlen] == '=')
     95 			return envstr + varlen + 1;
     96 		envptr++;
     97 	}
     98 
     99 	return NULL;
    100 }
    101