+++ /dev/null
-/*
- * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License, or any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
- * 02110-1301, USA.
- *
- * You can also choose to distribute this program under the terms of
- * the Unmodified Binary Distribution Licence (as given in the file
- * COPYING.UBDL), provided that you have satisfied its requirements.
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-/**
- * @file
- *
- * External memory allocation
- *
- */
-
-#include <limits.h>
-#include <string.h>
-#include <errno.h>
-#include <ipxe/uaccess.h>
-#include <ipxe/memblock.h>
-#include <ipxe/memmap.h>
-#include <ipxe/umalloc.h>
-
-/** Maximum usable address for external allocated memory */
-#define EM_MAX_ADDRESS 0xffffffffUL
-
-/** Alignment of external allocated memory */
-#define EM_ALIGN ( 4 * 1024 )
-
-/** An external memory block */
-struct external_memory {
- /** Size of this memory block (excluding this header) */
- size_t size;
- /** Block is currently in use */
- int used;
-};
-
-/** Top of heap */
-static void *top = NULL;
-
-/** Bottom of heap (current lowest allocated block) */
-static void *bottom = NULL;
-
-/** Remaining space on heap */
-static size_t heap_size;
-
-/** In-use memory region */
-struct used_region umalloc_used __used_region = {
- .name = "umalloc",
-};
-
-/**
- * Hide umalloc() region
- *
- * @v start Start of region
- * @v end End of region
- */
-static void hide_umalloc ( physaddr_t start, physaddr_t end ) {
-
- memmap_use ( &umalloc_used, start, ( end - start ) );
-}
-
-/**
- * Find largest usable memory region
- *
- * @ret start Start of region
- * @ret len Length of region
- */
-size_t largest_memblock ( void **start ) {
- struct memmap_region region;
- physaddr_t max = EM_MAX_ADDRESS;
- physaddr_t region_start;
- physaddr_t region_end;
- size_t region_len;
- size_t len = 0;
-
- /* Avoid returning uninitialised data on error */
- *start = NULL;
-
- /* Scan through all memory regions */
- for_each_memmap ( ®ion, 1 ) {
-
- /* Truncate block to maximum physical address */
- memmap_dump ( ®ion );
- if ( region.addr > max ) {
- DBGC ( ®ion, "...starts after maximum address "
- "%lx\n", max );
- break;
- }
- region_start = region.addr;
- if ( ! memmap_is_usable ( ®ion ) )
- continue;
- region_end = ( region_start + memmap_size ( ®ion ) );
- if ( region_end > max ) {
- DBGC ( ®ion, "...end truncated to maximum address "
- "%lx\n", max);
- region_end = 0; /* =max, given the wraparound */
- }
- region_len = ( region_end - region_start );
-
- /* Use largest block */
- if ( region_len > len ) {
- DBG ( "...new best block found\n" );
- *start = phys_to_virt ( region_start );
- len = region_len;
- }
- }
-
- return len;
-}
-
-/**
- * Initialise external heap
- *
- */
-static void init_eheap ( void ) {
- void *base;
-
- heap_size = largest_memblock ( &base );
- bottom = top = ( base + heap_size );
- DBG ( "External heap grows downwards from %lx (size %zx)\n",
- virt_to_phys ( top ), heap_size );
-}
-
-/**
- * Collect free blocks
- *
- */
-static void ecollect_free ( void ) {
- struct external_memory extmem;
- size_t len;
-
- /* Walk the free list and collect empty blocks */
- while ( bottom != top ) {
- memcpy ( &extmem, ( bottom - sizeof ( extmem ) ),
- sizeof ( extmem ) );
- if ( extmem.used )
- break;
- DBG ( "EXTMEM freeing [%lx,%lx)\n", virt_to_phys ( bottom ),
- ( virt_to_phys ( bottom ) + extmem.size ) );
- len = ( extmem.size + sizeof ( extmem ) );
- bottom += len;
- heap_size += len;
- }
-}
-
-/**
- * Reallocate external memory
- *
- * @v old_ptr Memory previously allocated by umalloc(), or NULL
- * @v new_size Requested size
- * @ret new_ptr Allocated memory, or NULL
- *
- * Calling realloc() with a new size of zero is a valid way to free a
- * memory block.
- */
-static void * memtop_urealloc ( void *ptr, size_t new_size ) {
- struct external_memory extmem;
- void *new = ptr;
- size_t align;
-
- /* (Re)initialise external memory allocator if necessary */
- if ( bottom == top )
- init_eheap();
-
- /* Get block properties into extmem */
- if ( ptr && ( ptr != NOWHERE ) ) {
- /* Determine old size */
- memcpy ( &extmem, ( ptr - sizeof ( extmem ) ),
- sizeof ( extmem ) );
- } else {
- /* Create a zero-length block */
- if ( heap_size < sizeof ( extmem ) ) {
- DBG ( "EXTMEM out of space\n" );
- return NULL;
- }
- ptr = bottom = ( bottom - sizeof ( extmem ) );
- heap_size -= sizeof ( extmem );
- DBG ( "EXTMEM allocating [%lx,%lx)\n",
- virt_to_phys ( ptr ), virt_to_phys ( ptr ) );
- extmem.size = 0;
- }
- extmem.used = ( new_size > 0 );
-
- /* Expand/shrink block if possible */
- if ( ptr == bottom ) {
- /* Update block */
- new = ( ptr - ( new_size - extmem.size ) );
- align = ( virt_to_phys ( new ) & ( EM_ALIGN - 1 ) );
- new_size += align;
- new -= align;
- if ( new_size > ( heap_size + extmem.size ) ) {
- DBG ( "EXTMEM out of space\n" );
- return NULL;
- }
- DBG ( "EXTMEM expanding [%lx,%lx) to [%lx,%lx)\n",
- virt_to_phys ( ptr ),
- ( virt_to_phys ( ptr ) + extmem.size ),
- virt_to_phys ( new ),
- ( virt_to_phys ( new ) + new_size ) );
- memmove ( new, ptr, ( ( extmem.size < new_size ) ?
- extmem.size : new_size ) );
- bottom = new;
- heap_size -= ( new_size - extmem.size );
- extmem.size = new_size;
- } else {
- /* Cannot expand; can only pretend to shrink */
- if ( new_size > extmem.size ) {
- /* Refuse to expand */
- DBG ( "EXTMEM cannot expand [%lx,%lx)\n",
- virt_to_phys ( ptr ),
- ( virt_to_phys ( ptr ) + extmem.size ) );
- return NULL;
- }
- }
-
- /* Write back block properties */
- memcpy ( ( new - sizeof ( extmem ) ), &extmem, sizeof ( extmem ) );
-
- /* Collect any free blocks and update hidden memory region */
- ecollect_free();
- hide_umalloc ( ( virt_to_phys ( bottom ) -
- ( ( bottom == top ) ? 0 : sizeof ( extmem ) ) ),
- virt_to_phys ( top ) );
-
- return ( new_size ? new : NOWHERE );
-}
-
-PROVIDE_UMALLOC ( memtop, urealloc, memtop_urealloc );
projects / thirdparty / ipxe.git / commitdiff
