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https://github.com/ipxe/ipxe
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[efi] Add EFI image format and basic runtime environment
We have EFI APIs for CPU I/O, PCI I/O, timers, console I/O, user access and user memory allocation. EFI executables are created using the vanilla GNU toolchain, with the EXE header handcrafted in assembly and relocations generated by a custom efilink utility.
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96
src/interface/efi/efi_umalloc.c
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96
src/interface/efi/efi_umalloc.c
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/*
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* Copyright (C) 2008 Michael Brown <mbrown@fensystems.co.uk>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <assert.h>
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#include <gpxe/umalloc.h>
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#include <gpxe/efi/efi.h>
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/** @file
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*
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* gPXE user memory allocation API for EFI
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*
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*/
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/** Equivalent of NOWHERE for user pointers */
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#define UNOWHERE ( ~UNULL )
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/**
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* Reallocate external memory
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*
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* @v old_ptr Memory previously allocated by umalloc(), or UNULL
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* @v new_size Requested size
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* @ret new_ptr Allocated memory, or UNULL
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*
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* Calling realloc() with a new size of zero is a valid way to free a
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* memory block.
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*/
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static userptr_t efi_urealloc ( userptr_t old_ptr, size_t new_size ) {
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EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
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EFI_PHYSICAL_ADDRESS phys_addr;
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unsigned int new_pages, old_pages;
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userptr_t new_ptr = UNOWHERE;
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size_t old_size;
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EFI_STATUS efirc;
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/* Allocate new memory if necessary. If allocation fails,
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* return without touching the old block.
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*/
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if ( new_size ) {
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new_pages = ( EFI_SIZE_TO_PAGES ( new_size ) + 1 );
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if ( ( efirc = bs->AllocatePages ( AllocateAnyPages,
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EfiBootServicesData,
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new_pages,
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&phys_addr ) ) != 0 ) {
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DBG ( "EFI could not allocate %d pages: %lx\n",
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new_pages, efirc );
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return UNULL;
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}
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assert ( phys_addr != 0 );
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new_ptr = phys_to_user ( phys_addr + EFI_PAGE_SIZE );
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copy_to_user ( new_ptr, -EFI_PAGE_SIZE,
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&new_size, sizeof ( new_size ) );
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DBG ( "EFI allocated %d pages at %llx\n",
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new_pages, phys_addr );
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}
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/* Copy across relevant part of the old data region (if any),
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* then free it. Note that at this point either (a) new_ptr
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* is valid, or (b) new_size is 0; either way, the memcpy() is
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* valid.
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*/
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if ( old_ptr && ( old_ptr != UNOWHERE ) ) {
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copy_from_user ( &old_size, old_ptr, -EFI_PAGE_SIZE,
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sizeof ( old_size ) );
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memcpy_user ( new_ptr, 0, old_ptr, 0,
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( (old_size < new_size) ? old_size : new_size ));
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old_pages = ( EFI_SIZE_TO_PAGES ( old_size ) + 1 );
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phys_addr = user_to_phys ( old_ptr, -EFI_PAGE_SIZE );
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if ( ( efirc = bs->FreePages ( phys_addr, old_pages ) ) != 0 ){
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DBG ( "EFI could not free %d pages at %llx: %lx\n",
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old_pages, phys_addr, efirc );
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/* Not fatal; we have leaked memory but successfully
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* allocated (if asked to do so).
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*/
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}
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DBG ( "EFI freed %d pages at %llx\n", old_pages, phys_addr );
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}
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return new_ptr;
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}
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PROVIDE_UMALLOC ( efi, urealloc, efi_urealloc );
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