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., 675 Mass Ave, Cambridge, MA 02139, USA.
17 */
18
19 FILE_LICENCE ( GPL2_OR_LATER );
20
21 #include <assert.h>
22 #include <gpxe/umalloc.h>
23 #include <gpxe/efi/efi.h>
24
25 /** @file
26 *
27 * gPXE user memory allocation API for EFI
28 *
29 */
30
31 /** Equivalent of NOWHERE for user pointers */
32 #define UNOWHERE ( ~UNULL )
33
34 /**
35 * Reallocate external memory
36 *
37 * @v old_ptr Memory previously allocated by umalloc(), or UNULL
38 * @v new_size Requested size
39 * @ret new_ptr Allocated memory, or UNULL
40 *
41 * Calling realloc() with a new size of zero is a valid way to free a
42 * memory block.
43 */
efi_urealloc(userptr_t old_ptr,size_t new_size)44 static userptr_t efi_urealloc ( userptr_t old_ptr, size_t new_size ) {
45 EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
46 EFI_PHYSICAL_ADDRESS phys_addr;
47 unsigned int new_pages, old_pages;
48 userptr_t new_ptr = UNOWHERE;
49 size_t old_size;
50 EFI_STATUS efirc;
51
52 /* Allocate new memory if necessary. If allocation fails,
53 * return without touching the old block.
54 */
55 if ( new_size ) {
56 new_pages = ( EFI_SIZE_TO_PAGES ( new_size ) + 1 );
57 if ( ( efirc = bs->AllocatePages ( AllocateAnyPages,
58 EfiBootServicesData,
59 new_pages,
60 &phys_addr ) ) != 0 ) {
61 DBG ( "EFI could not allocate %d pages: %s\n",
62 new_pages, efi_strerror ( efirc ) );
63 return UNULL;
64 }
65 assert ( phys_addr != 0 );
66 new_ptr = phys_to_user ( phys_addr + EFI_PAGE_SIZE );
67 copy_to_user ( new_ptr, -EFI_PAGE_SIZE,
68 &new_size, sizeof ( new_size ) );
69 DBG ( "EFI allocated %d pages at %llx\n",
70 new_pages, phys_addr );
71 }
72
73 /* Copy across relevant part of the old data region (if any),
74 * then free it. Note that at this point either (a) new_ptr
75 * is valid, or (b) new_size is 0; either way, the memcpy() is
76 * valid.
77 */
78 if ( old_ptr && ( old_ptr != UNOWHERE ) ) {
79 copy_from_user ( &old_size, old_ptr, -EFI_PAGE_SIZE,
80 sizeof ( old_size ) );
81 memcpy_user ( new_ptr, 0, old_ptr, 0,
82 ( (old_size < new_size) ? old_size : new_size ));
83 old_pages = ( EFI_SIZE_TO_PAGES ( old_size ) + 1 );
84 phys_addr = user_to_phys ( old_ptr, -EFI_PAGE_SIZE );
85 if ( ( efirc = bs->FreePages ( phys_addr, old_pages ) ) != 0 ){
86 DBG ( "EFI could not free %d pages at %llx: %s\n",
87 old_pages, phys_addr, efi_strerror ( efirc ) );
88 /* Not fatal; we have leaked memory but successfully
89 * allocated (if asked to do so).
90 */
91 }
92 DBG ( "EFI freed %d pages at %llx\n", old_pages, phys_addr );
93 }
94
95 return new_ptr;
96 }
97
98 PROVIDE_UMALLOC ( efi, urealloc, efi_urealloc );
99