gpxe/src/arch/i386/firmware/pcbios/memmap.c - platform/external/syslinux - Git at Google

 /*
  * 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 <stdint.h>
 #include <errno.h>
 #include <realmode.h>
 #include <bios.h>
 #include <memsizes.h>
 #include <gpxe/memmap.h>

 /**
  * @file
  *
  * Memory mapping
  *
  */

 /** Magic value for INT 15,e820 calls */
 #define SMAP ( 0x534d4150 )

 /** An INT 15,e820 memory map entry */
 struct e820_entry {
 	/** Start of region */
 	uint64_t start;
 	/** Length of region */
 	uint64_t len;
 	/** Type of region */
 	uint32_t type;
 	/** Extended attributes (optional) */
 	uint32_t attrs;
 } __attribute__ (( packed ));

 #define E820_TYPE_RAM		1 /**< Normal memory */
 #define E820_TYPE_RESERVED	2 /**< Reserved and unavailable */
 #define E820_TYPE_ACPI		3 /**< ACPI reclaim memory */
 #define E820_TYPE_NVS		4 /**< ACPI NVS memory */

 #define E820_ATTR_ENABLED	0x00000001UL
 #define E820_ATTR_NONVOLATILE	0x00000002UL
 #define E820_ATTR_UNKNOWN	0xfffffffcUL

 #define E820_MIN_SIZE		20

 /** Buffer for INT 15,e820 calls */
 static struct e820_entry __bss16 ( e820buf );
 #define e820buf __use_data16 ( e820buf )

 /**
  * Get size of extended memory via INT 15,e801
  *
  * @ret extmem		Extended memory size, in kB, or 0
  */
 static unsigned int extmemsize_e801 ( void ) {
 	uint16_t extmem_1m_to_16m_k, extmem_16m_plus_64k;
 	uint16_t confmem_1m_to_16m_k, confmem_16m_plus_64k;
 	unsigned int flags;
 	unsigned int extmem;

 	__asm__ __volatile__ ( REAL_CODE ( "stc\n\t"
 					   "int $0x15\n\t"
 					   "pushfw\n\t"
 					   "popw %w0\n\t" )
 			       : "=r" ( flags ),
 				 "=a" ( extmem_1m_to_16m_k ),
 				 "=b" ( extmem_16m_plus_64k ),
 				 "=c" ( confmem_1m_to_16m_k ),
 				 "=d" ( confmem_16m_plus_64k )
 			       : "a" ( 0xe801 ) );

 	if ( flags & CF ) {
 		DBG ( "INT 15,e801 failed with CF set\n" );
 		return 0;
 	}

 	if ( ! ( extmem_1m_to_16m_k | extmem_16m_plus_64k ) ) {
 		DBG ( "INT 15,e801 extmem=0, using confmem\n" );
 		extmem_1m_to_16m_k = confmem_1m_to_16m_k;
 		extmem_16m_plus_64k = confmem_16m_plus_64k;
 	}

 	extmem = ( extmem_1m_to_16m_k + ( extmem_16m_plus_64k * 64 ) );
 	DBG ( "INT 15,e801 extended memory size %d+64*%d=%d kB "
 	      "[100000,%llx)\n", extmem_1m_to_16m_k, extmem_16m_plus_64k,
 	      extmem, ( 0x100000 + ( ( ( uint64_t ) extmem ) * 1024 ) ) );

 	/* Sanity check.  Some BIOSes report the entire 4GB address
 	 * space as available, which cannot be correct (since that
 	 * would leave no address space available for 32-bit PCI
 	 * BARs).
 	 */
 	if ( extmem == ( 0x400000 - 0x400 ) ) {
 		DBG ( "INT 15,e801 reported whole 4GB; assuming insane\n" );
 		return 0;
 	}

 	return extmem;
 }

 /**
  * Get size of extended memory via INT 15,88
  *
  * @ret extmem		Extended memory size, in kB
  */
 static unsigned int extmemsize_88 ( void ) {
 	uint16_t extmem;

 	/* Ignore CF; it is not reliable for this call */
 	__asm__ __volatile__ ( REAL_CODE ( "int $0x15" )
 			       : "=a" ( extmem ) : "a" ( 0x8800 ) );

 	DBG ( "INT 15,88 extended memory size %d kB [100000, %x)\n",
 	      extmem, ( 0x100000 + ( extmem * 1024 ) ) );
 	return extmem;
 }

 /**
  * Get size of extended memory
  *
  * @ret extmem		Extended memory size, in kB
  *
  * Note that this is only an approximation; for an accurate picture,
  * use the E820 memory map obtained via get_memmap();
  */
 unsigned int extmemsize ( void ) {
 	unsigned int extmem;

 	/* Try INT 15,e801 first, then fall back to INT 15,88 */
 	extmem = extmemsize_e801();
 	if ( ! extmem )
 		extmem = extmemsize_88();
 	return extmem;
 }

 /**
  * Get e820 memory map
  *
  * @v memmap		Memory map to fill in
  * @ret rc		Return status code
  */
 static int meme820 ( struct memory_map *memmap ) {
 	struct memory_region *region = memmap->regions;
 	uint32_t next = 0;
 	uint32_t smap;
 	size_t size;
 	unsigned int flags;
 	unsigned int discard_D;

 	/* Clear the E820 buffer.  Do this once before starting,
 	 * rather than on each call; some BIOSes rely on the contents
 	 * being preserved between calls.
 	 */
 	memset ( &e820buf, 0, sizeof ( e820buf ) );

 	do {
 		/* Some BIOSes corrupt %esi for fun. Guard against
 		 * this by telling gcc that all non-output registers
 		 * may be corrupted.
 		 */
 		__asm__ __volatile__ ( REAL_CODE ( "pushl %%ebp\n\t"
 						   "stc\n\t"
 						   "int $0x15\n\t"
 						   "pushfw\n\t"
 						   "popw %%dx\n\t"
 						   "popl %%ebp\n\t" )
 				       : "=a" ( smap ), "=b" ( next ),
 					 "=c" ( size ), "=d" ( flags ),
 					 "=D" ( discard_D )
 				       : "a" ( 0xe820 ), "b" ( next ),
 					 "D" ( __from_data16 ( &e820buf ) ),
 					 "c" ( sizeof ( e820buf ) ),
 					 "d" ( SMAP )
 				       : "esi", "memory" );

 		if ( smap != SMAP ) {
 			DBG ( "INT 15,e820 failed SMAP signature check\n" );
 			return -ENOTSUP;
 		}

 		if ( size < E820_MIN_SIZE ) {
 			DBG ( "INT 15,e820 returned only %zd bytes\n", size );
 			return -EINVAL;
 		}

 		if ( flags & CF ) {
 			DBG ( "INT 15,e820 terminated on CF set\n" );
 			break;
 		}

 		/* If first region is not RAM, assume map is invalid */
 		if ( ( memmap->count == 0 ) &&
 		     ( e820buf.type != E820_TYPE_RAM ) ) {
 		       DBG ( "INT 15,e820 failed, first entry not RAM\n" );
 		       return -EINVAL;
 		}

 		DBG ( "INT 15,e820 region [%llx,%llx) type %d",
 		      e820buf.start, ( e820buf.start + e820buf.len ),
 		      ( int ) e820buf.type );
 		if ( size > offsetof ( typeof ( e820buf ), attrs ) ) {
 			DBG ( " (%s", ( ( e820buf.attrs & E820_ATTR_ENABLED )
 					? "enabled" : "disabled" ) );
 			if ( e820buf.attrs & E820_ATTR_NONVOLATILE )
 				DBG ( ", non-volatile" );
 			if ( e820buf.attrs & E820_ATTR_UNKNOWN )
 				DBG ( ", other [%08x]", e820buf.attrs );
 			DBG ( ")" );
 		}
 		DBG ( "\n" );

 		/* Discard non-RAM regions */
 		if ( e820buf.type != E820_TYPE_RAM )
 			continue;

 		/* Check extended attributes, if present */
 		if ( size > offsetof ( typeof ( e820buf ), attrs ) ) {
 			if ( ! ( e820buf.attrs & E820_ATTR_ENABLED ) )
 				continue;
 			if ( e820buf.attrs & E820_ATTR_NONVOLATILE )
 				continue;
 		}

 		region->start = e820buf.start;
 		region->end = e820buf.start + e820buf.len;
 		region++;
 		memmap->count++;

 		if ( memmap->count >= ( sizeof ( memmap->regions ) /
 					sizeof ( memmap->regions[0] ) ) ) {
 			DBG ( "INT 15,e820 too many regions returned\n" );
 			/* Not a fatal error; what we've got so far at
 			 * least represents valid regions of memory,
 			 * even if we couldn't get them all.
 			 */
 			break;
 		}
 	} while ( next != 0 );

 	/* Sanity checks.  Some BIOSes report complete garbage via INT
 	 * 15,e820 (especially at POST time), despite passing the
 	 * signature checks.  We currently check for a base memory
 	 * region (starting at 0) and at least one high memory region
 	 * (starting at 0x100000).
 	 */
 	if ( memmap->count < 2 ) {
 		DBG ( "INT 15,e820 returned only %d regions; assuming "
 		      "insane\n", memmap->count );
 		return -EINVAL;
 	}
 	if ( memmap->regions[0].start != 0 ) {
 		DBG ( "INT 15,e820 region 0 starts at %llx (expected 0); "
 		      "assuming insane\n", memmap->regions[0].start );
 		return -EINVAL;
 	}
 	if ( memmap->regions[1].start != 0x100000 ) {
 		DBG ( "INT 15,e820 region 1 starts at %llx (expected 100000); "
 		      "assuming insane\n", memmap->regions[0].start );
 		return -EINVAL;
 	}

 	return 0;
 }

 /**
  * Get memory map
  *
  * @v memmap		Memory map to fill in
  */
 void get_memmap ( struct memory_map *memmap ) {
 	unsigned int basemem, extmem;
 	int rc;

 	DBG ( "Fetching system memory map\n" );

 	/* Clear memory map */
 	memset ( memmap, 0, sizeof ( *memmap ) );

 	/* Get base and extended memory sizes */
 	basemem = basememsize();
 	DBG ( "FBMS base memory size %d kB [0,%x)\n",
 	      basemem, ( basemem * 1024 ) );
 	extmem = extmemsize();

 	/* Try INT 15,e820 first */
 	if ( ( rc = meme820 ( memmap ) ) == 0 ) {
 		DBG ( "Obtained system memory map via INT 15,e820\n" );
 		return;
 	}

 	/* Fall back to constructing a map from basemem and extmem sizes */
 	DBG ( "INT 15,e820 failed; constructing map\n" );
 	memmap->regions[0].end = ( basemem * 1024 );
 	memmap->regions[1].start = 0x100000;
 	memmap->regions[1].end = 0x100000 + ( extmem * 1024 );
 	memmap->count = 2;
 }
	/*
	* 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 <stdint.h>
	#include <errno.h>
	#include <realmode.h>
	#include <bios.h>
	#include <memsizes.h>
	#include <gpxe/memmap.h>

	/**
	* @file
	*
	* Memory mapping
	*
	*/

	/** Magic value for INT 15,e820 calls */
	#define SMAP ( 0x534d4150 )

	/** An INT 15,e820 memory map entry */
	struct e820_entry {
	/** Start of region */
	uint64_t start;
	/** Length of region */
	uint64_t len;
	/** Type of region */
	uint32_t type;
	/** Extended attributes (optional) */
	uint32_t attrs;
	} __attribute__ (( packed ));

	#define E820_TYPE_RAM 1 /*< Normal memory /
	#define E820_TYPE_RESERVED 2 /*< Reserved and unavailable /
	#define E820_TYPE_ACPI 3 /*< ACPI reclaim memory /
	#define E820_TYPE_NVS 4 /*< ACPI NVS memory /

	#define E820_ATTR_ENABLED 0x00000001UL
	#define E820_ATTR_NONVOLATILE 0x00000002UL
	#define E820_ATTR_UNKNOWN 0xfffffffcUL

	#define E820_MIN_SIZE 20

	/** Buffer for INT 15,e820 calls */
	static struct e820_entry __bss16 ( e820buf );
	#define e820buf __use_data16 ( e820buf )

	/**
	* Get size of extended memory via INT 15,e801
	*
	* @ret extmem Extended memory size, in kB, or 0
	*/
	static unsigned int extmemsize_e801 ( void ) {
	uint16_t extmem_1m_to_16m_k, extmem_16m_plus_64k;
	uint16_t confmem_1m_to_16m_k, confmem_16m_plus_64k;
	unsigned int flags;
	unsigned int extmem;

	__asm__ __volatile__ ( REAL_CODE ( "stc\n\t"
	"int $0x15\n\t"
	"pushfw\n\t"
	"popw %w0\n\t" )
	: "=r" ( flags ),
	"=a" ( extmem_1m_to_16m_k ),
	"=b" ( extmem_16m_plus_64k ),
	"=c" ( confmem_1m_to_16m_k ),
	"=d" ( confmem_16m_plus_64k )
	: "a" ( 0xe801 ) );

	if ( flags & CF ) {
	DBG ( "INT 15,e801 failed with CF set\n" );
	return 0;
	}

	if ( ! ( extmem_1m_to_16m_k \| extmem_16m_plus_64k ) ) {
	DBG ( "INT 15,e801 extmem=0, using confmem\n" );
	extmem_1m_to_16m_k = confmem_1m_to_16m_k;
	extmem_16m_plus_64k = confmem_16m_plus_64k;
	}

	extmem = ( extmem_1m_to_16m_k + ( extmem_16m_plus_64k * 64 ) );
	DBG ( "INT 15,e801 extended memory size %d+64*%d=%d kB "
	"[100000,%llx)\n", extmem_1m_to_16m_k, extmem_16m_plus_64k,
	extmem, ( 0x100000 + ( ( ( uint64_t ) extmem ) * 1024 ) ) );

	/* Sanity check. Some BIOSes report the entire 4GB address
	* space as available, which cannot be correct (since that
	* would leave no address space available for 32-bit PCI
	* BARs).
	*/
	if ( extmem == ( 0x400000 - 0x400 ) ) {
	DBG ( "INT 15,e801 reported whole 4GB; assuming insane\n" );
	return 0;
	}

	return extmem;
	}

	/**
	* Get size of extended memory via INT 15,88
	*
	* @ret extmem Extended memory size, in kB
	*/
	static unsigned int extmemsize_88 ( void ) {
	uint16_t extmem;

	/* Ignore CF; it is not reliable for this call */
	__asm__ __volatile__ ( REAL_CODE ( "int $0x15" )
	: "=a" ( extmem ) : "a" ( 0x8800 ) );

	DBG ( "INT 15,88 extended memory size %d kB [100000, %x)\n",
	extmem, ( 0x100000 + ( extmem * 1024 ) ) );
	return extmem;
	}

	/**
	* Get size of extended memory
	*
	* @ret extmem Extended memory size, in kB
	*
	* Note that this is only an approximation; for an accurate picture,
	* use the E820 memory map obtained via get_memmap();
	*/
	unsigned int extmemsize ( void ) {
	unsigned int extmem;

	/* Try INT 15,e801 first, then fall back to INT 15,88 */
	extmem = extmemsize_e801();
	if ( ! extmem )
	extmem = extmemsize_88();
	return extmem;
	}

	/**
	* Get e820 memory map
	*
	* @v memmap Memory map to fill in
	* @ret rc Return status code
	*/
	static int meme820 ( struct memory_map *memmap ) {
	struct memory_region *region = memmap->regions;
	uint32_t next = 0;
	uint32_t smap;
	size_t size;
	unsigned int flags;
	unsigned int discard_D;

	/* Clear the E820 buffer. Do this once before starting,
	* rather than on each call; some BIOSes rely on the contents
	* being preserved between calls.
	*/
	memset ( &e820buf, 0, sizeof ( e820buf ) );

	do {
	/* Some BIOSes corrupt %esi for fun. Guard against
	* this by telling gcc that all non-output registers
	* may be corrupted.
	*/
	__asm__ __volatile__ ( REAL_CODE ( "pushl %%ebp\n\t"
	"stc\n\t"
	"int $0x15\n\t"
	"pushfw\n\t"
	"popw %%dx\n\t"
	"popl %%ebp\n\t" )
	: "=a" ( smap ), "=b" ( next ),
	"=c" ( size ), "=d" ( flags ),
	"=D" ( discard_D )
	: "a" ( 0xe820 ), "b" ( next ),
	"D" ( __from_data16 ( &e820buf ) ),
	"c" ( sizeof ( e820buf ) ),
	"d" ( SMAP )
	: "esi", "memory" );

	if ( smap != SMAP ) {
	DBG ( "INT 15,e820 failed SMAP signature check\n" );
	return -ENOTSUP;
	}

	if ( size < E820_MIN_SIZE ) {
	DBG ( "INT 15,e820 returned only %zd bytes\n", size );
	return -EINVAL;
	}

	if ( flags & CF ) {
	DBG ( "INT 15,e820 terminated on CF set\n" );
	break;
	}

	/* If first region is not RAM, assume map is invalid */
	if ( ( memmap->count == 0 ) &&
	( e820buf.type != E820_TYPE_RAM ) ) {
	DBG ( "INT 15,e820 failed, first entry not RAM\n" );
	return -EINVAL;
	}

	DBG ( "INT 15,e820 region [%llx,%llx) type %d",
	e820buf.start, ( e820buf.start + e820buf.len ),
	( int ) e820buf.type );
	if ( size > offsetof ( typeof ( e820buf ), attrs ) ) {
	DBG ( " (%s", ( ( e820buf.attrs & E820_ATTR_ENABLED )
	? "enabled" : "disabled" ) );
	if ( e820buf.attrs & E820_ATTR_NONVOLATILE )
	DBG ( ", non-volatile" );
	if ( e820buf.attrs & E820_ATTR_UNKNOWN )
	DBG ( ", other [%08x]", e820buf.attrs );
	DBG ( ")" );
	}
	DBG ( "\n" );

	/* Discard non-RAM regions */
	if ( e820buf.type != E820_TYPE_RAM )
	continue;

	/* Check extended attributes, if present */
	if ( size > offsetof ( typeof ( e820buf ), attrs ) ) {
	if ( ! ( e820buf.attrs & E820_ATTR_ENABLED ) )
	continue;
	if ( e820buf.attrs & E820_ATTR_NONVOLATILE )
	continue;
	}

	region->start = e820buf.start;
	region->end = e820buf.start + e820buf.len;
	region++;
	memmap->count++;

	if ( memmap->count >= ( sizeof ( memmap->regions ) /
	sizeof ( memmap->regions[0] ) ) ) {
	DBG ( "INT 15,e820 too many regions returned\n" );
	/* Not a fatal error; what we've got so far at
	* least represents valid regions of memory,
	* even if we couldn't get them all.
	*/
	break;
	}
	} while ( next != 0 );

	/* Sanity checks. Some BIOSes report complete garbage via INT
	* 15,e820 (especially at POST time), despite passing the
	* signature checks. We currently check for a base memory
	* region (starting at 0) and at least one high memory region
	* (starting at 0x100000).
	*/
	if ( memmap->count < 2 ) {
	DBG ( "INT 15,e820 returned only %d regions; assuming "
	"insane\n", memmap->count );
	return -EINVAL;
	}
	if ( memmap->regions[0].start != 0 ) {
	DBG ( "INT 15,e820 region 0 starts at %llx (expected 0); "
	"assuming insane\n", memmap->regions[0].start );
	return -EINVAL;
	}
	if ( memmap->regions[1].start != 0x100000 ) {
	DBG ( "INT 15,e820 region 1 starts at %llx (expected 100000); "
	"assuming insane\n", memmap->regions[0].start );
	return -EINVAL;
	}

	return 0;
	}

	/**
	* Get memory map
	*
	* @v memmap Memory map to fill in
	*/
	void get_memmap ( struct memory_map *memmap ) {
	unsigned int basemem, extmem;
	int rc;

	DBG ( "Fetching system memory map\n" );

	/* Clear memory map */
	memset ( memmap, 0, sizeof ( *memmap ) );

	/* Get base and extended memory sizes */
	basemem = basememsize();
	DBG ( "FBMS base memory size %d kB [0,%x)\n",
	basemem, ( basemem * 1024 ) );
	extmem = extmemsize();

	/* Try INT 15,e820 first */
	if ( ( rc = meme820 ( memmap ) ) == 0 ) {
	DBG ( "Obtained system memory map via INT 15,e820\n" );
	return;
	}

	/* Fall back to constructing a map from basemem and extmem sizes */
	DBG ( "INT 15,e820 failed; constructing map\n" );
	memmap->regions[0].end = ( basemem * 1024 );
	memmap->regions[1].start = 0x100000;
	memmap->regions[1].end = 0x100000 + ( extmem * 1024 );
	memmap->count = 2;
	}