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Annotation of qemu/roms/ipxe/src/interface/efi/efi_umalloc.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (C) 2008 Michael Brown <[email protected]>.
        !             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 <ipxe/umalloc.h>
        !            23: #include <ipxe/efi/efi.h>
        !            24: 
        !            25: /** @file
        !            26:  *
        !            27:  * iPXE 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 );

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