1 /*
2 * Copyright (C) 2008 Michael Brown <mbrown@fensystems.co.uk>.
3 *
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.
8 *
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.
13 *
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
17 * 02110-1301, USA.
18 *
19 * You can also choose to distribute this program under the terms of
20 * the Unmodified Binary Distribution Licence (as given in the file
21 * COPYING.UBDL), provided that you have satisfied its requirements.
22 */
23
24 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
25
26 #include <string.h>
27 #include <errno.h>
28 #include <assert.h>
29 #include <ipxe/umalloc.h>
30 #include <ipxe/efi/efi.h>
31
32 /** @file
33 *
34 * iPXE user memory allocation API for EFI
35 *
36 */
37
38 /** Equivalent of NOWHERE for user pointers */
39 #define UNOWHERE ( ~UNULL )
40
41 /**
42 * Reallocate external memory
43 *
44 * @v old_ptr Memory previously allocated by umalloc(), or UNULL
45 * @v new_size Requested size
46 * @ret new_ptr Allocated memory, or UNULL
47 *
48 * Calling realloc() with a new size of zero is a valid way to free a
49 * memory block.
50 */
efi_urealloc(userptr_t old_ptr,size_t new_size)51 static userptr_t efi_urealloc ( userptr_t old_ptr, size_t new_size ) {
52 EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
53 EFI_PHYSICAL_ADDRESS phys_addr;
54 unsigned int new_pages, old_pages;
55 userptr_t new_ptr = UNOWHERE;
56 size_t old_size;
57 EFI_STATUS efirc;
58 int rc;
59
60 /* Allocate new memory if necessary. If allocation fails,
61 * return without touching the old block.
62 */
63 if ( new_size ) {
64 new_pages = ( EFI_SIZE_TO_PAGES ( new_size ) + 1 );
65 if ( ( efirc = bs->AllocatePages ( AllocateAnyPages,
66 EfiBootServicesData,
67 new_pages,
68 &phys_addr ) ) != 0 ) {
69 rc = -EEFI ( efirc );
70 DBG ( "EFI could not allocate %d pages: %s\n",
71 new_pages, strerror ( rc ) );
72 return UNULL;
73 }
74 assert ( phys_addr != 0 );
75 new_ptr = phys_to_user ( phys_addr + EFI_PAGE_SIZE );
76 copy_to_user ( new_ptr, -EFI_PAGE_SIZE,
77 &new_size, sizeof ( new_size ) );
78 DBG ( "EFI allocated %d pages at %llx\n",
79 new_pages, phys_addr );
80 }
81
82 /* Copy across relevant part of the old data region (if any),
83 * then free it. Note that at this point either (a) new_ptr
84 * is valid, or (b) new_size is 0; either way, the memcpy() is
85 * valid.
86 */
87 if ( old_ptr && ( old_ptr != UNOWHERE ) ) {
88 copy_from_user ( &old_size, old_ptr, -EFI_PAGE_SIZE,
89 sizeof ( old_size ) );
90 memcpy_user ( new_ptr, 0, old_ptr, 0,
91 ( (old_size < new_size) ? old_size : new_size ));
92 old_pages = ( EFI_SIZE_TO_PAGES ( old_size ) + 1 );
93 phys_addr = user_to_phys ( old_ptr, -EFI_PAGE_SIZE );
94 if ( ( efirc = bs->FreePages ( phys_addr, old_pages ) ) != 0 ){
95 rc = -EEFI ( efirc );
96 DBG ( "EFI could not free %d pages at %llx: %s\n",
97 old_pages, phys_addr, strerror ( rc ) );
98 /* Not fatal; we have leaked memory but successfully
99 * allocated (if asked to do so).
100 */
101 }
102 DBG ( "EFI freed %d pages at %llx\n", old_pages, phys_addr );
103 }
104
105 return new_ptr;
106 }
107
108 PROVIDE_UMALLOC ( efi, urealloc, efi_urealloc );
109