text: /*
   * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
   *
   * 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 2 of the
   * License, or 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, write to the Free Software
   * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   */
  
  FILE_LICENCE ( GPL2_OR_LATER );
  
  #include <gpxe/uaccess.h>
  #include <gpxe/init.h>
  #include <registers.h>
  #include <biosint.h>
  #include <pxe.h>
  #include <pxe_call.h>
  
  /** @file
   *
   * PXE API entry point
   */
  
  /** Vector for chaining INT 1A */
  extern struct segoff __text16 ( pxe_int_1a_vector );
  #define pxe_int_1a_vector __use_text16 ( pxe_int_1a_vector )
  
  /** INT 1A handler */
  extern void pxe_int_1a ( void );
  
  /** INT 1A hooked flag */
  static int int_1a_hooked = 0;
  
  /** A function pointer to hold any PXE API call
   *
   * Used by pxe_api_call() to avoid large swathes of duplicated code.
   */
  union pxenv_call {
  	PXENV_EXIT_t ( * any ) ( union u_PXENV_ANY * );
  	PXENV_EXIT_t ( * unknown ) ( struct s_PXENV_UNKNOWN * );
  	PXENV_EXIT_t ( * unload_stack ) ( struct s_PXENV_UNLOAD_STACK * );
  	PXENV_EXIT_t ( * get_cached_info )
  			( struct s_PXENV_GET_CACHED_INFO * );
  	PXENV_EXIT_t ( * restart_tftp ) ( struct s_PXENV_TFTP_READ_FILE * );
  	PXENV_EXIT_t ( * start_undi ) ( struct s_PXENV_START_UNDI * );
  	PXENV_EXIT_t ( * stop_undi ) ( struct s_PXENV_STOP_UNDI * );
  	PXENV_EXIT_t ( * start_base ) ( struct s_PXENV_START_BASE * );
  	PXENV_EXIT_t ( * stop_base ) ( struct s_PXENV_STOP_BASE * );
  	PXENV_EXIT_t ( * tftp_open ) ( struct s_PXENV_TFTP_OPEN * );
  	PXENV_EXIT_t ( * tftp_close ) ( struct s_PXENV_TFTP_CLOSE * );
  	PXENV_EXIT_t ( * tftp_read ) ( struct s_PXENV_TFTP_READ * );
  	PXENV_EXIT_t ( * tftp_read_file ) ( struct s_PXENV_TFTP_READ_FILE * );
  	PXENV_EXIT_t ( * tftp_get_fsize ) ( struct s_PXENV_TFTP_GET_FSIZE * );
  	PXENV_EXIT_t ( * udp_open ) ( struct s_PXENV_UDP_OPEN * );
  	PXENV_EXIT_t ( * udp_close ) ( struct s_PXENV_UDP_CLOSE * );
  	PXENV_EXIT_t ( * udp_write ) ( struct s_PXENV_UDP_WRITE * );
  	PXENV_EXIT_t ( * udp_read ) ( struct s_PXENV_UDP_READ * );
  	PXENV_EXIT_t ( * undi_startup ) ( struct s_PXENV_UNDI_STARTUP * );
  	PXENV_EXIT_t ( * undi_cleanup ) ( struct s_PXENV_UNDI_CLEANUP * );
  	PXENV_EXIT_t ( * undi_initialize )
  			( struct s_PXENV_UNDI_INITIALIZE * );
  	PXENV_EXIT_t ( * undi_reset_adapter ) ( struct s_PXENV_UNDI_RESET * );
  	PXENV_EXIT_t ( * undi_shutdown ) ( struct s_PXENV_UNDI_SHUTDOWN * );
  	PXENV_EXIT_t ( * undi_open ) ( struct s_PXENV_UNDI_OPEN * );
  	PXENV_EXIT_t ( * undi_close ) ( struct s_PXENV_UNDI_CLOSE * );
  	PXENV_EXIT_t ( * undi_transmit ) ( struct s_PXENV_UNDI_TRANSMIT * );
  	PXENV_EXIT_t ( * undi_set_mcast_address )
  			( struct s_PXENV_UNDI_SET_MCAST_ADDRESS * );
  	PXENV_EXIT_t ( * undi_set_station_address )
  			( struct s_PXENV_UNDI_SET_STATION_ADDRESS * );
  	PXENV_EXIT_t ( * undi_set_packet_filter )
  			( struct s_PXENV_UNDI_SET_PACKET_FILTER * );
  	PXENV_EXIT_t ( * undi_get_information )
  			( struct s_PXENV_UNDI_GET_INFORMATION * );
  	PXENV_EXIT_t ( * undi_get_statistics )
  			( struct s_PXENV_UNDI_GET_STATISTICS * );
  	PXENV_EXIT_t ( * undi_clear_statistics )
  			( struct s_PXENV_UNDI_CLEAR_STATISTICS * );
  	PXENV_EXIT_t ( * undi_initiate_diags )
  			( struct s_PXENV_UNDI_INITIATE_DIAGS * );
  	PXENV_EXIT_t ( * undi_force_interrupt )
  			( struct s_PXENV_UNDI_FORCE_INTERRUPT * );
  	PXENV_EXIT_t ( * undi_get_mcast_address )
  			( struct s_PXENV_UNDI_GET_MCAST_ADDRESS * );
  	PXENV_EXIT_t ( * undi_get_nic_type )
  			( struct s_PXENV_UNDI_GET_NIC_TYPE * );
  	PXENV_EXIT_t ( * undi_get_iface_info )
  			( struct s_PXENV_UNDI_GET_IFACE_INFO * );
  	PXENV_EXIT_t ( * undi_get_state ) ( struct s_PXENV_UNDI_GET_STATE * );
  	PXENV_EXIT_t ( * undi_isr ) ( struct s_PXENV_UNDI_ISR * );
  	PXENV_EXIT_t ( * file_open ) ( struct s_PXENV_FILE_OPEN * );
  	PXENV_EXIT_t ( * file_close ) ( struct s_PXENV_FILE_CLOSE * );
  	PXENV_EXIT_t ( * file_select ) ( struct s_PXENV_FILE_SELECT * );
  	PXENV_EXIT_t ( * file_read ) ( struct s_PXENV_FILE_READ * );
  	PXENV_EXIT_t ( * get_file_size ) ( struct s_PXENV_GET_FILE_SIZE * );
  	PXENV_EXIT_t ( * file_exec ) ( struct s_PXENV_FILE_EXEC * );
  	PXENV_EXIT_t ( * file_api_check ) ( struct s_PXENV_FILE_API_CHECK * );
  	PXENV_EXIT_t ( * file_exit_hook ) ( struct s_PXENV_FILE_EXIT_HOOK * );
  };
  
  /**
   * Handle an unknown PXE API call
   *
   * @v pxenv_unknown 			Pointer to a struct s_PXENV_UNKNOWN
   * @ret #PXENV_EXIT_FAILURE		Always
   * @err #PXENV_STATUS_UNSUPPORTED	Always
   */
  static PXENV_EXIT_t pxenv_unknown ( struct s_PXENV_UNKNOWN *pxenv_unknown ) {
  	pxenv_unknown->Status = PXENV_STATUS_UNSUPPORTED;
  	return PXENV_EXIT_FAILURE;
  }
  
  /**
   * Dispatch PXE API call
   *
   * @v bx		PXE opcode
   * @v es:di		Address of PXE parameter block
   * @ret ax		PXE exit code
   */
  __asmcall void pxe_api_call ( struct i386_all_regs *ix86 ) {
  	int opcode = ix86->regs.bx;
  	userptr_t parameters = real_to_user ( ix86->segs.es, ix86->regs.di );
  	size_t param_len;
  	union u_PXENV_ANY pxenv_any;
  	union pxenv_call pxenv_call;
  	PXENV_EXIT_t ret;
  
  	switch ( opcode ) {
  	case PXENV_UNLOAD_STACK:
  		pxenv_call.unload_stack = pxenv_unload_stack;
  		param_len = sizeof ( pxenv_any.unload_stack );
  		break;
  	case PXENV_GET_CACHED_INFO:
  		pxenv_call.get_cached_info = pxenv_get_cached_info;
  		param_len = sizeof ( pxenv_any.get_cached_info );
  		break;
  	case PXENV_RESTART_TFTP:
  		pxenv_call.restart_tftp = pxenv_restart_tftp;
  		param_len = sizeof ( pxenv_any.restart_tftp );
  		break;
  	case PXENV_START_UNDI:
  		pxenv_call.start_undi = pxenv_start_undi;
  		param_len = sizeof ( pxenv_any.start_undi );
  		break;
  	case PXENV_STOP_UNDI:
  		pxenv_call.stop_undi = pxenv_stop_undi;
  		param_len = sizeof ( pxenv_any.stop_undi );
  		break;
  	case PXENV_START_BASE:
  		pxenv_call.start_base = pxenv_start_base;
  		param_len = sizeof ( pxenv_any.start_base );
  		break;
  	case PXENV_STOP_BASE:
  		pxenv_call.stop_base = pxenv_stop_base;
  		param_len = sizeof ( pxenv_any.stop_base );
  		break;
  	case PXENV_TFTP_OPEN:
  		pxenv_call.tftp_open = pxenv_tftp_open;
  		param_len = sizeof ( pxenv_any.tftp_open );
  		break;
  	case PXENV_TFTP_CLOSE:
  		pxenv_call.tftp_close = pxenv_tftp_close;
  		param_len = sizeof ( pxenv_any.tftp_close );
  		break;
  	case PXENV_TFTP_READ:
  		pxenv_call.tftp_read = pxenv_tftp_read;
  		param_len = sizeof ( pxenv_any.tftp_read );
  		break;
  	case PXENV_TFTP_READ_FILE:
  		pxenv_call.tftp_read_file = pxenv_tftp_read_file;
  		param_len = sizeof ( pxenv_any.tftp_read_file );
  		break;
  	case PXENV_TFTP_GET_FSIZE:
  		pxenv_call.tftp_get_fsize = pxenv_tftp_get_fsize;
  		param_len = sizeof ( pxenv_any.tftp_get_fsize );
  		break;
  	case PXENV_UDP_OPEN:
  		pxenv_call.udp_open = pxenv_udp_open;
  		param_len = sizeof ( pxenv_any.udp_open );
  		break;
  	case PXENV_UDP_CLOSE:
  		pxenv_call.udp_close = pxenv_udp_close;
  		param_len = sizeof ( pxenv_any.udp_close );
  		break;
  	case PXENV_UDP_WRITE:
  		pxenv_call.udp_write = pxenv_udp_write;
  		param_len = sizeof ( pxenv_any.udp_write );
  		break;
  	case PXENV_UDP_READ:
  		pxenv_call.udp_read = pxenv_udp_read;
  		param_len = sizeof ( pxenv_any.udp_read );
  		break;
  	case PXENV_UNDI_STARTUP:
  		pxenv_call.undi_startup = pxenv_undi_startup;
  		param_len = sizeof ( pxenv_any.undi_startup );
  		break;
  	case PXENV_UNDI_CLEANUP:
  		pxenv_call.undi_cleanup = pxenv_undi_cleanup;
  		param_len = sizeof ( pxenv_any.undi_cleanup );
  		break;
  	case PXENV_UNDI_INITIALIZE:
  		pxenv_call.undi_initialize = pxenv_undi_initialize;
  		param_len = sizeof ( pxenv_any.undi_initialize );
  		break;
  	case PXENV_UNDI_RESET_ADAPTER:
  		pxenv_call.undi_reset_adapter = pxenv_undi_reset_adapter;
  		param_len = sizeof ( pxenv_any.undi_reset_adapter );
  		break;
  	case PXENV_UNDI_SHUTDOWN:
  		pxenv_call.undi_shutdown = pxenv_undi_shutdown;
  		param_len = sizeof ( pxenv_any.undi_shutdown );
  		break;
  	case PXENV_UNDI_OPEN:
  		pxenv_call.undi_open = pxenv_undi_open;
  		param_len = sizeof ( pxenv_any.undi_open );
  		break;
  	case PXENV_UNDI_CLOSE:
  		pxenv_call.undi_close = pxenv_undi_close;
  		param_len = sizeof ( pxenv_any.undi_close );
  		break;
  	case PXENV_UNDI_TRANSMIT:
  		pxenv_call.undi_transmit = pxenv_undi_transmit;
  		param_len = sizeof ( pxenv_any.undi_transmit );
  		break;
  	case PXENV_UNDI_SET_MCAST_ADDRESS:
  		pxenv_call.undi_set_mcast_address =
  			pxenv_undi_set_mcast_address;
  		param_len = sizeof ( pxenv_any.undi_set_mcast_address );
  		break;
  	case PXENV_UNDI_SET_STATION_ADDRESS:
  		pxenv_call.undi_set_station_address =
  			pxenv_undi_set_station_address;
  		param_len = sizeof ( pxenv_any.undi_set_station_address );
  		break;
  	case PXENV_UNDI_SET_PACKET_FILTER:
  		pxenv_call.undi_set_packet_filter =
  			pxenv_undi_set_packet_filter;
  		param_len = sizeof ( pxenv_any.undi_set_packet_filter );
  		break;
  	case PXENV_UNDI_GET_INFORMATION:
  		pxenv_call.undi_get_information = pxenv_undi_get_information;
  		param_len = sizeof ( pxenv_any.undi_get_information );
  		break;
  	case PXENV_UNDI_GET_STATISTICS:
  		pxenv_call.undi_get_statistics = pxenv_undi_get_statistics;
  		param_len = sizeof ( pxenv_any.undi_get_statistics );
  		break;
  	case PXENV_UNDI_CLEAR_STATISTICS:
  		pxenv_call.undi_clear_statistics = pxenv_undi_clear_statistics;
  		param_len = sizeof ( pxenv_any.undi_clear_statistics );
  		break;
  	case PXENV_UNDI_INITIATE_DIAGS:
  		pxenv_call.undi_initiate_diags = pxenv_undi_initiate_diags;
  		param_len = sizeof ( pxenv_any.undi_initiate_diags );
  		break;
  	case PXENV_UNDI_FORCE_INTERRUPT:
  		pxenv_call.undi_force_interrupt = pxenv_undi_force_interrupt;
  		param_len = sizeof ( pxenv_any.undi_force_interrupt );
  		break;
  	case PXENV_UNDI_GET_MCAST_ADDRESS:
  		pxenv_call.undi_get_mcast_address =
  			pxenv_undi_get_mcast_address;
  		param_len = sizeof ( pxenv_any.undi_get_mcast_address );
  		break;
  	case PXENV_UNDI_GET_NIC_TYPE:
  		pxenv_call.undi_get_nic_type = pxenv_undi_get_nic_type;
  		param_len = sizeof ( pxenv_any.undi_get_nic_type );
  		break;
  	case PXENV_UNDI_GET_IFACE_INFO:
  		pxenv_call.undi_get_iface_info = pxenv_undi_get_iface_info;
  		param_len = sizeof ( pxenv_any.undi_get_iface_info );
  		break;
  	case PXENV_UNDI_ISR:
  		pxenv_call.undi_isr = pxenv_undi_isr;
  		param_len = sizeof ( pxenv_any.undi_isr );
  		break;
  	case PXENV_FILE_OPEN:
  		pxenv_call.file_open = pxenv_file_open;
  		param_len = sizeof ( pxenv_any.file_open );
  		break;
  	case PXENV_FILE_CLOSE:
  		pxenv_call.file_close = pxenv_file_close;
  		param_len = sizeof ( pxenv_any.file_close );
  		break;
  	case PXENV_FILE_SELECT:
  		pxenv_call.file_select = pxenv_file_select;
  		param_len = sizeof ( pxenv_any.file_select );
  		break;
  	case PXENV_FILE_READ:
  		pxenv_call.file_read = pxenv_file_read;
  		param_len = sizeof ( pxenv_any.file_read );
  		break;
  	case PXENV_GET_FILE_SIZE:
  		pxenv_call.get_file_size = pxenv_get_file_size;
  		param_len = sizeof ( pxenv_any.get_file_size );
  		break;
  	case PXENV_FILE_EXEC:
  		pxenv_call.file_exec = pxenv_file_exec;
  		param_len = sizeof ( pxenv_any.file_exec );
  		break;
  	case PXENV_FILE_API_CHECK:
  		pxenv_call.file_api_check = pxenv_file_api_check;
  		param_len = sizeof ( pxenv_any.file_api_check );
  		break;
  	case PXENV_FILE_EXIT_HOOK:
  		pxenv_call.file_exit_hook = pxenv_file_exit_hook;
  		param_len = sizeof ( pxenv_any.file_exit_hook );
  		break;
  	default:
  		DBG ( "PXENV_UNKNOWN_%hx", opcode );
  		pxenv_call.unknown = pxenv_unknown;
  		param_len = sizeof ( pxenv_any.unknown );
  		break;
  	}
  
  	/* Copy parameter block from caller */
  	copy_from_user ( &pxenv_any, parameters, 0, param_len );
  
  	/* Set default status in case child routine fails to do so */
  	pxenv_any.Status = PXENV_STATUS_FAILURE;
  
  	/* Hand off to relevant API routine */
  	DBG ( "[" );
  	ret = pxenv_call.any ( &pxenv_any );
  	if ( pxenv_any.Status != PXENV_STATUS_SUCCESS ) {
  		DBG ( " %02x", pxenv_any.Status );
  	}
  	if ( ret != PXENV_EXIT_SUCCESS ) {
  		DBG ( ret == PXENV_EXIT_FAILURE ? " err" : " ??" );
  	}
  	DBG ( "]" );
  	
  	/* Copy modified parameter block back to caller and return */
  	copy_to_user ( parameters, 0, &pxenv_any, param_len );
  	ix86->regs.ax = ret;
  }
  
  /**
   * Dispatch weak PXE API call with PXE stack available
   *
   * @v ix86		Registers for PXE call
   * @ret present		Zero (PXE stack present)
   */
  int _pxe_api_call_weak ( struct i386_all_regs *ix86 )
  {
  	pxe_api_call ( ix86 );
  	return 0;
  }
  
  /**
   * Dispatch PXE loader call
   *
   * @v es:di		Address of PXE parameter block
   * @ret ax		PXE exit code
   */
  __asmcall void pxe_loader_call ( struct i386_all_regs *ix86 ) {
  	userptr_t uparams = real_to_user ( ix86->segs.es, ix86->regs.di );
  	struct s_UNDI_LOADER params;
  	PXENV_EXIT_t ret;
  
  	/* Copy parameter block from caller */
  	copy_from_user ( &params, uparams, 0, sizeof ( params ) );
  
  	/* Fill in ROM segment address */
  	ppxe.UNDIROMID.segment = ix86->segs.ds;
  
  	/* Set default status in case child routine fails to do so */
  	params.Status = PXENV_STATUS_FAILURE;
  
  	/* Call UNDI loader */
  	ret = undi_loader ( &params );
  
  	/* Copy modified parameter block back to caller and return */
  	copy_to_user ( uparams, 0, &params, sizeof ( params ) );
  	ix86->regs.ax = ret;
  }
  
  /**
   * Calculate byte checksum as used by PXE
   *
   * @v data		Data
   * @v size		Length of data
   * @ret sum		Checksum
   */
  static uint8_t pxe_checksum ( void *data, size_t size ) {
  	uint8_t *bytes = data;
  	uint8_t sum = 0;
  
  	while ( size-- ) {
  		sum += *bytes++;
  	}
  	return sum;
  }
  
  /**
   * Initialise !PXE and PXENV+ structures
   *
   */
  static void pxe_init_structures ( void ) {
  	uint32_t rm_cs_phys = ( rm_cs << 4 );
  	uint32_t rm_ds_phys = ( rm_ds << 4 );
  
  	/* Fill in missing segment fields */
  	ppxe.EntryPointSP.segment = rm_cs;
  	ppxe.EntryPointESP.segment = rm_cs;
  	ppxe.Stack.segment_address = rm_ds;
  	ppxe.Stack.Physical_address = rm_ds_phys;
  	ppxe.UNDIData.segment_address = rm_ds;
  	ppxe.UNDIData.Physical_address = rm_ds_phys;
  	ppxe.UNDICode.segment_address = rm_cs;
  	ppxe.UNDICode.Physical_address = rm_cs_phys;
  	ppxe.UNDICodeWrite.segment_address = rm_cs;
  	ppxe.UNDICodeWrite.Physical_address = rm_cs_phys;
  	pxenv.RMEntry.segment = rm_cs;
  	pxenv.StackSeg = rm_ds;
  	pxenv.UNDIDataSeg = rm_ds;
  	pxenv.UNDICodeSeg = rm_cs;
  	pxenv.PXEPtr.segment = rm_cs;
  
  	/* Update checksums */
  	ppxe.StructCksum -= pxe_checksum ( &ppxe, sizeof ( ppxe ) );
  	pxenv.Checksum -= pxe_checksum ( &pxenv, sizeof ( pxenv ) );
  }
  
  /** PXE structure initialiser */
  struct init_fn pxe_init_fn __init_fn ( INIT_NORMAL ) = {
  	.initialise = pxe_init_structures,
  };
  
  /**
   * Activate PXE stack
   *
   * @v netdev		Net device to use as PXE net device
   */
  void pxe_activate ( struct net_device *netdev ) {
  
  	/* Ensure INT 1A is hooked */
  	if ( ! int_1a_hooked ) {
  		hook_bios_interrupt ( 0x1a, ( unsigned int ) pxe_int_1a,
  				      &pxe_int_1a_vector );
  		int_1a_hooked = 1;
  	}
  
  	/* Set PXE network device */
  	pxe_set_netdev ( netdev );
  }
  
  /**
   * Deactivate PXE stack
   *
   * @ret rc		Return status code
   */
  int pxe_deactivate ( void ) {
  	int rc;
  
  	/* Clear PXE network device */
  	pxe_set_netdev ( NULL );
  
  	/* Ensure INT 1A is unhooked, if possible */
  	if ( int_1a_hooked ) {
  		if ( ( rc = unhook_bios_interrupt ( 0x1a,
  						    (unsigned int) pxe_int_1a,
  						    &pxe_int_1a_vector ))!= 0){
  			DBG ( "Could not unhook INT 1A: %s\n",
  			      strerror ( rc ) );
  			return rc;
  		}
  		int_1a_hooked = 0;
  	}
  
  	return 0;
  }
  
  /**
   * Start PXE NBP at 0000:7c00
   *
   * @ret rc		Return status code
   */
  int pxe_start_nbp ( void ) {
  	int discard_b, discard_c, discard_d, discard_D;
  	uint16_t rc;
  
  	/* Far call to PXE NBP */
  	__asm__ __volatile__ ( REAL_CODE ( "movw %%cx, %%es\n\t"
  					   "pushw %%es\n\t"
  					   "pushw %%di\n\t"
  					   "sti\n\t"
  					   "lcall $0, $0x7c00\n\t"
  					   "addw $4, %%sp\n\t" )
  			       : "=a" ( rc ), "=b" ( discard_b ),
  				 "=c" ( discard_c ), "=d" ( discard_d ),
  				 "=D" ( discard_D )
  			       : "a" ( 0 ), "b" ( __from_text16 ( &pxenv ) ),
  			         "c" ( rm_cs ),
  			         "d" ( virt_to_phys ( &pxenv ) ),
  				 "D" ( __from_text16 ( &ppxe ) )
  			       : "esi", "ebp", "memory" );
  
  	return rc;
  }
  