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[umalloc] Split largest_memblock() function out from init_eheap()
Signed-off-by: Michael Brown <mcb30@ipxe.org>
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/* | ||
* Copyright (C) 2012 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 (at your option) 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., 51 Franklin Street, Fifth Floor, Boston, MA | ||
* 02110-1301, USA. | ||
*/ | ||
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FILE_LICENCE ( GPL2_OR_LATER ); | ||
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/** @file | ||
* | ||
* Largest memory block | ||
* | ||
*/ | ||
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#include <stdint.h> | ||
#include <ipxe/uaccess.h> | ||
#include <ipxe/io.h> | ||
#include <ipxe/memblock.h> | ||
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/** | ||
* Find largest usable memory region | ||
* | ||
* @ret start Start of region | ||
* @ret len Length of region | ||
*/ | ||
size_t largest_memblock ( userptr_t *start ) { | ||
struct memory_map memmap; | ||
struct memory_region *region; | ||
physaddr_t max = ~( ( physaddr_t ) 0 ); | ||
physaddr_t region_start; | ||
physaddr_t region_end; | ||
size_t region_len; | ||
unsigned int i; | ||
size_t len = 0; | ||
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/* Avoid returning uninitialised data on error */ | ||
*start = UNULL; | ||
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/* Scan through all memory regions */ | ||
get_memmap ( &memmap ); | ||
for ( i = 0 ; i < memmap.count ; i++ ) { | ||
region = &memmap.regions[i]; | ||
DBG ( "Considering [%llx,%llx)\n", region->start, region->end ); | ||
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/* Truncate block to maximum physical address */ | ||
if ( region->start > max ) { | ||
DBG ( "...starts after maximum address %lx\n", max ); | ||
continue; | ||
} | ||
region_start = region->start; | ||
if ( region->end > max ) { | ||
DBG ( "...end truncated to maximum address %lx\n", max); | ||
region_end = 0; /* =max, given the wraparound */ | ||
} else { | ||
region_end = region->end; | ||
} | ||
region_len = ( region_end - region_start ); | ||
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/* Use largest block */ | ||
if ( region_len > len ) { | ||
DBG ( "...new best block found\n" ); | ||
*start = phys_to_user ( region_start ); | ||
len = region_len; | ||
} | ||
} | ||
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return len; | ||
} |
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#ifndef _IPXE_MEMBLOCK_H | ||
#define _IPXE_MEMBLOCK_H | ||
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/** @file | ||
* | ||
* Largest memory block | ||
* | ||
*/ | ||
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FILE_LICENCE ( GPL2_OR_LATER ); | ||
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#include <stdint.h> | ||
#include <ipxe/uaccess.h> | ||
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extern size_t largest_memblock ( userptr_t *start ); | ||
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#endif /* _IPXE_MEMBLOCK_H */ |