2 * Copyright (C) 2008 Michael Brown <mbrown@fensystems.co.uk>.
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.
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.
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., 51 Franklin Street, Fifth Floor, Boston, MA
20 FILE_LICENCE ( GPL2_OR_LATER );
25 #include <ipxe/umalloc.h>
26 #include <ipxe/efi/efi.h>
30 * iPXE user memory allocation API for EFI
34 /** Equivalent of NOWHERE for user pointers */
35 #define UNOWHERE ( ~UNULL )
38 * Reallocate external memory
40 * @v old_ptr Memory previously allocated by umalloc(), or UNULL
41 * @v new_size Requested size
42 * @ret new_ptr Allocated memory, or UNULL
44 * Calling realloc() with a new size of zero is a valid way to free a
47 static userptr_t efi_urealloc ( userptr_t old_ptr, size_t new_size ) {
48 EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
49 EFI_PHYSICAL_ADDRESS phys_addr;
50 unsigned int new_pages, old_pages;
51 userptr_t new_ptr = UNOWHERE;
56 /* Allocate new memory if necessary. If allocation fails,
57 * return without touching the old block.
60 new_pages = ( EFI_SIZE_TO_PAGES ( new_size ) + 1 );
61 if ( ( efirc = bs->AllocatePages ( AllocateAnyPages,
64 &phys_addr ) ) != 0 ) {
66 DBG ( "EFI could not allocate %d pages: %s\n",
67 new_pages, strerror ( rc ) );
70 assert ( phys_addr != 0 );
71 new_ptr = phys_to_user ( phys_addr + EFI_PAGE_SIZE );
72 copy_to_user ( new_ptr, -EFI_PAGE_SIZE,
73 &new_size, sizeof ( new_size ) );
74 DBG ( "EFI allocated %d pages at %llx\n",
75 new_pages, phys_addr );
78 /* Copy across relevant part of the old data region (if any),
79 * then free it. Note that at this point either (a) new_ptr
80 * is valid, or (b) new_size is 0; either way, the memcpy() is
83 if ( old_ptr && ( old_ptr != UNOWHERE ) ) {
84 copy_from_user ( &old_size, old_ptr, -EFI_PAGE_SIZE,
85 sizeof ( old_size ) );
86 memcpy_user ( new_ptr, 0, old_ptr, 0,
87 ( (old_size < new_size) ? old_size : new_size ));
88 old_pages = ( EFI_SIZE_TO_PAGES ( old_size ) + 1 );
89 phys_addr = user_to_phys ( old_ptr, -EFI_PAGE_SIZE );
90 if ( ( efirc = bs->FreePages ( phys_addr, old_pages ) ) != 0 ){
92 DBG ( "EFI could not free %d pages at %llx: %s\n",
93 old_pages, phys_addr, strerror ( rc ) );
94 /* Not fatal; we have leaked memory but successfully
95 * allocated (if asked to do so).
98 DBG ( "EFI freed %d pages at %llx\n", old_pages, phys_addr );
104 PROVIDE_UMALLOC ( efi, urealloc, efi_urealloc );