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/*
* Copyright (C) 2008 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.
*/
#include <assert.h>
#include <gpxe/umalloc.h>
#include <gpxe/efi/efi.h>
/** @file
*
* gPXE user memory allocation API for EFI
*
*/
/** Equivalent of NOWHERE for user pointers */
#define UNOWHERE ( ~UNULL )
/**
* Reallocate external memory
*
* @v old_ptr Memory previously allocated by umalloc(), or UNULL
* @v new_size Requested size
* @ret new_ptr Allocated memory, or UNULL
*
* Calling realloc() with a new size of zero is a valid way to free a
* memory block.
*/
static userptr_t efi_urealloc ( userptr_t old_ptr, size_t new_size ) {
EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
EFI_PHYSICAL_ADDRESS phys_addr;
unsigned int new_pages, old_pages;
userptr_t new_ptr = UNOWHERE;
size_t old_size;
EFI_STATUS efirc;
/* Allocate new memory if necessary. If allocation fails,
* return without touching the old block.
*/
if ( new_size ) {
new_pages = ( EFI_SIZE_TO_PAGES ( new_size ) + 1 );
if ( ( efirc = bs->AllocatePages ( AllocateAnyPages,
EfiBootServicesData,
new_pages,
&phys_addr ) ) != 0 ) {
DBG ( "EFI could not allocate %d pages: %s\n",
new_pages, efi_strerror ( efirc ) );
return UNULL;
}
assert ( phys_addr != 0 );
new_ptr = phys_to_user ( phys_addr + EFI_PAGE_SIZE );
copy_to_user ( new_ptr, -EFI_PAGE_SIZE,
&new_size, sizeof ( new_size ) );
DBG ( "EFI allocated %d pages at %llx\n",
new_pages, phys_addr );
}
/* Copy across relevant part of the old data region (if any),
* then free it. Note that at this point either (a) new_ptr
* is valid, or (b) new_size is 0; either way, the memcpy() is
* valid.
*/
if ( old_ptr && ( old_ptr != UNOWHERE ) ) {
copy_from_user ( &old_size, old_ptr, -EFI_PAGE_SIZE,
sizeof ( old_size ) );
memcpy_user ( new_ptr, 0, old_ptr, 0,
( (old_size < new_size) ? old_size : new_size ));
old_pages = ( EFI_SIZE_TO_PAGES ( old_size ) + 1 );
phys_addr = user_to_phys ( old_ptr, -EFI_PAGE_SIZE );
if ( ( efirc = bs->FreePages ( phys_addr, old_pages ) ) != 0 ){
DBG ( "EFI could not free %d pages at %llx: %s\n",
old_pages, phys_addr, efi_strerror ( efirc ) );
/* Not fatal; we have leaked memory but successfully
* allocated (if asked to do so).
*/
}
DBG ( "EFI freed %d pages at %llx\n", old_pages, phys_addr );
}
return new_ptr;
}
PROVIDE_UMALLOC ( efi, urealloc, efi_urealloc );
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