1 /* 2 * Copyright (C) 2008 Michael Brown <mbrown (at) 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 */ 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
