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      1 /*
      2  * Copyright (C) 2007 Michael Brown <mbrown (at) fensystems.co.uk>.
      3  *
      4  * This program is free software; you can redistribute it and/or
      5  * modify it under the terms of the GNU General Public License as
      6  * published by the Free Software Foundation; either version 2 of the
      7  * License, or any later version.
      8  *
      9  * This program is distributed in the hope that it will be useful, but
     10  * WITHOUT ANY WARRANTY; without even the implied warranty of
     11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     12  * General Public License for more details.
     13  *
     14  * You should have received a copy of the GNU General Public License
     15  * along with this program; if not, write to the Free Software
     16  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
     17  */
     18 
     19 FILE_LICENCE ( GPL2_OR_LATER );
     20 
     21 #include <gpxe/dhcp.h>
     22 #include <pxeparent.h>
     23 #include <pxe_api.h>
     24 #include <pxe_types.h>
     25 #include <pxe.h>
     26 
     27 /** @file
     28  *
     29  * Call interface to parent PXE stack
     30  *
     31  */
     32 
     33 /**
     34  * Name PXE API call
     35  *
     36  * @v function		API call number
     37  * @ret name		API call name
     38  */
     39 static inline __attribute__ (( always_inline )) const char *
     40 pxeparent_function_name ( unsigned int function ) {
     41 	switch ( function ) {
     42 	case PXENV_START_UNDI:
     43 		return "PXENV_START_UNDI";
     44 	case PXENV_STOP_UNDI:
     45 		return "PXENV_STOP_UNDI";
     46 	case PXENV_UNDI_STARTUP:
     47 		return "PXENV_UNDI_STARTUP";
     48 	case PXENV_UNDI_CLEANUP:
     49 		return "PXENV_UNDI_CLEANUP";
     50 	case PXENV_UNDI_INITIALIZE:
     51 		return "PXENV_UNDI_INITIALIZE";
     52 	case PXENV_UNDI_RESET_ADAPTER:
     53 		return "PXENV_UNDI_RESET_ADAPTER";
     54 	case PXENV_UNDI_SHUTDOWN:
     55 		return "PXENV_UNDI_SHUTDOWN";
     56 	case PXENV_UNDI_OPEN:
     57 		return "PXENV_UNDI_OPEN";
     58 	case PXENV_UNDI_CLOSE:
     59 		return "PXENV_UNDI_CLOSE";
     60 	case PXENV_UNDI_TRANSMIT:
     61 		return "PXENV_UNDI_TRANSMIT";
     62 	case PXENV_UNDI_SET_MCAST_ADDRESS:
     63 		return "PXENV_UNDI_SET_MCAST_ADDRESS";
     64 	case PXENV_UNDI_SET_STATION_ADDRESS:
     65 		return "PXENV_UNDI_SET_STATION_ADDRESS";
     66 	case PXENV_UNDI_SET_PACKET_FILTER:
     67 		return "PXENV_UNDI_SET_PACKET_FILTER";
     68 	case PXENV_UNDI_GET_INFORMATION:
     69 		return "PXENV_UNDI_GET_INFORMATION";
     70 	case PXENV_UNDI_GET_STATISTICS:
     71 		return "PXENV_UNDI_GET_STATISTICS";
     72 	case PXENV_UNDI_CLEAR_STATISTICS:
     73 		return "PXENV_UNDI_CLEAR_STATISTICS";
     74 	case PXENV_UNDI_INITIATE_DIAGS:
     75 		return "PXENV_UNDI_INITIATE_DIAGS";
     76 	case PXENV_UNDI_FORCE_INTERRUPT:
     77 		return "PXENV_UNDI_FORCE_INTERRUPT";
     78 	case PXENV_UNDI_GET_MCAST_ADDRESS:
     79 		return "PXENV_UNDI_GET_MCAST_ADDRESS";
     80 	case PXENV_UNDI_GET_NIC_TYPE:
     81 		return "PXENV_UNDI_GET_NIC_TYPE";
     82 	case PXENV_UNDI_GET_IFACE_INFO:
     83 		return "PXENV_UNDI_GET_IFACE_INFO";
     84 	/*
     85 	 * Duplicate case value; this is a bug in the PXE specification.
     86 	 *
     87 	 *	case PXENV_UNDI_GET_STATE:
     88 	 *		return "PXENV_UNDI_GET_STATE";
     89 	 */
     90 	case PXENV_UNDI_ISR:
     91 		return "PXENV_UNDI_ISR";
     92 	case PXENV_GET_CACHED_INFO:
     93 		return "PXENV_GET_CACHED_INFO";
     94 	default:
     95 		return "UNKNOWN API CALL";
     96 	}
     97 }
     98 
     99 /**
    100  * PXE parent parameter block
    101  *
    102  * Used as the paramter block for all parent PXE API calls.  Resides in base
    103  * memory.
    104  */
    105 static union u_PXENV_ANY __bss16 ( pxeparent_params );
    106 #define pxeparent_params __use_data16 ( pxeparent_params )
    107 
    108 /** PXE parent entry point
    109  *
    110  * Used as the indirection vector for all parent PXE API calls.  Resides in
    111  * base memory.
    112  */
    113 SEGOFF16_t __bss16 ( pxeparent_entry_point );
    114 #define pxeparent_entry_point __use_data16 ( pxeparent_entry_point )
    115 
    116 /**
    117  * Issue parent PXE API call
    118  *
    119  * @v entry		Parent PXE stack entry point
    120  * @v function		API call number
    121  * @v params		PXE parameter block
    122  * @v params_len	Length of PXE parameter block
    123  * @ret rc		Return status code
    124  */
    125 int pxeparent_call ( SEGOFF16_t entry, unsigned int function,
    126 		     void *params, size_t params_len ) {
    127 	PXENV_EXIT_t exit;
    128 	int discard_b, discard_D;
    129 	int rc;
    130 
    131 	/* Copy parameter block and entry point */
    132 	assert ( params_len <= sizeof ( pxeparent_params ) );
    133 	memcpy ( &pxeparent_params, params, params_len );
    134 	memcpy ( &pxeparent_entry_point, &entry, sizeof ( entry ) );
    135 
    136 	/* Call real-mode entry point.  This calling convention will
    137 	 * work with both the !PXE and the PXENV+ entry points.
    138 	 */
    139 	__asm__ __volatile__ ( REAL_CODE ( "pushw %%es\n\t"
    140 					   "pushw %%di\n\t"
    141 					   "pushw %%bx\n\t"
    142 					   "lcall *pxeparent_entry_point\n\t"
    143 					   "addw $6, %%sp\n\t" )
    144 			       : "=a" ( exit ), "=b" ( discard_b ),
    145 			         "=D" ( discard_D )
    146 			       : "b" ( function ),
    147 			         "D" ( __from_data16 ( &pxeparent_params ) )
    148 			       : "ecx", "edx", "esi", "ebp" );
    149 
    150 	/* PXE API calls may rudely change the status of A20 and not
    151 	 * bother to restore it afterwards.  Intel is known to be
    152 	 * guilty of this.
    153 	 *
    154 	 * Note that we will return to this point even if A20 gets
    155 	 * screwed up by the parent PXE stack, because Etherboot always
    156 	 * resides in an even megabyte of RAM.
    157 	 */
    158 	gateA20_set();
    159 
    160 	/* Determine return status code based on PXENV_EXIT and
    161 	 * PXENV_STATUS
    162 	 */
    163 	if ( exit == PXENV_EXIT_SUCCESS ) {
    164 		rc = 0;
    165 	} else {
    166 		rc = -pxeparent_params.Status;
    167 		/* Paranoia; don't return success for the combination
    168 		 * of PXENV_EXIT_FAILURE but PXENV_STATUS_SUCCESS
    169 		 */
    170 		if ( rc == 0 )
    171 			rc = -EIO;
    172 	}
    173 
    174 	/* If anything goes wrong, print as much debug information as
    175 	 * it's possible to give.
    176 	 */
    177 	if ( rc != 0 ) {
    178 		SEGOFF16_t rm_params = {
    179 			.segment = rm_ds,
    180 			.offset = __from_data16 ( &pxeparent_params ),
    181 		};
    182 
    183 		DBG ( "PXEPARENT %s failed: %s\n",
    184 		       pxeparent_function_name ( function ), strerror ( rc ) );
    185 		DBG ( "PXEPARENT parameters at %04x:%04x length "
    186 		       "%#02zx, entry point at %04x:%04x\n",
    187 		       rm_params.segment, rm_params.offset, params_len,
    188 		       pxeparent_entry_point.segment,
    189 		       pxeparent_entry_point.offset );
    190 		DBG ( "PXEPARENT parameters provided:\n" );
    191 		DBG_HDA ( rm_params, params, params_len );
    192 		DBG ( "PXEPARENT parameters returned:\n" );
    193 		DBG_HDA ( rm_params, &pxeparent_params, params_len );
    194 	}
    195 
    196 	/* Copy parameter block back */
    197 	memcpy ( params, &pxeparent_params, params_len );
    198 
    199 	return rc;
    200 }
    201 
    202