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#include "etherboot.h"
#include "init.h"
#include "memsizes.h"
#include <assert.h>
#include "heap.h"
struct heap_block {
size_t size;
unsigned int align;
char data[0];
};
/* Linker symbols */
extern char _text[];
extern char _end[];
static physaddr_t heap_start;
/*
* Find the largest contiguous area of memory that I can use for the
* heap.
*
*/
static void init_heap ( void ) {
unsigned int i;
physaddr_t eb_start, eb_end;
physaddr_t size;
size = 0;
/* Region occupied by Etherboot */
eb_start = virt_to_phys ( _text );
eb_end = virt_to_phys ( _end );
for ( i = 0 ; i < meminfo.map_count ; i++ ) {
physaddr_t r_start, r_end, r_size;
physaddr_t pre_eb, post_eb;
/* Get start and end addresses of the region */
if ( meminfo.map[i].type != E820_RAM )
continue;
if ( meminfo.map[i].addr > ULONG_MAX )
continue;
r_start = meminfo.map[i].addr;
if ( r_start + meminfo.map[i].size > ULONG_MAX ) {
r_end = ULONG_MAX;
} else {
r_end = r_start + meminfo.map[i].size;
}
/* Avoid overlap with Etherboot. When Etherboot is
* completely contained within the region, choose the
* larger of the two remaining portions.
*/
if ( ( eb_start < r_end ) && ( eb_end > r_start ) ) {
pre_eb = ( eb_start > r_start ) ?
( eb_start - r_start ) : 0;
post_eb = ( r_end > eb_end ) ?
( r_end - eb_end ) : 0;
if ( pre_eb > post_eb ) {
r_end = eb_start;
} else {
r_start = eb_end;
}
}
/* Use the biggest region. Where two regions are the
* same size, use the later region. (Provided that
* the memory map is laid out in a sensible order,
* this should give us the higher region.)
*/
r_size = r_end - r_start;
if ( r_size >= size ) {
heap_start = r_start;
heap_end = r_end;
size = r_size;
}
}
assert ( size != 0 );
DBG ( "HEAP using region [%x,%x)\n", heap_start, heap_end );
heap_ptr = heap_end;
}
/*
* Allocate a block from the heap.
*
*/
static inline physaddr_t block_alloc_addr ( physaddr_t heap_ptr,
size_t size, unsigned int align ) {
return ( ( ( heap_ptr - size ) & ~( align - 1 ) )
- sizeof ( struct heap_block ) );
}
void * emalloc ( size_t size, unsigned int align ) {
struct heap_block *block;
physaddr_t addr;
assert ( ( align & ( align - 1 ) ) == 0 );
addr = block_alloc_addr ( heap_ptr, size, align );
if ( addr < heap_start ) {
DBG ( "HEAP no space for %x bytes (alignment %d) in [%x,%x)\n",
size, align, heap_start, heap_ptr );
return NULL;
}
block = phys_to_virt ( addr );
block->size = ( heap_ptr - addr );
block->align = align;
DBG ( "HEAP allocated %x bytes (alignment %d) at %x [%x,%x)\n",
size, align, virt_to_phys ( block->data ), addr, heap_ptr );
heap_ptr = addr;
return block->data;
}
/*
* Allocate all remaining space on the heap
*
*/
void * emalloc_all ( size_t *size ) {
*size = heap_ptr - heap_start - sizeof ( struct heap_block );
return emalloc ( *size, sizeof ( void * ) );
}
/*
* Free a heap block
*
*/
static inline physaddr_t block_free_addr ( size_t size ) {
return heap_ptr + size;
}
void efree ( void *ptr ) {
struct heap_block *block;
assert ( ptr == phys_to_virt ( heap_ptr + sizeof ( size_t ) ) );
block = ( struct heap_block * )
( ptr - offsetof ( struct heap_block, data ) );
heap_ptr = block_free_addr ( block->size );
DBG ( "HEAP freed %x [%x,%x)\n", virt_to_phys ( ptr ),
virt_to_phys ( block ), heap_ptr );
assert ( heap_ptr <= heap_end );
}
/*
* Free all allocated heap blocks
*
*/
void efree_all ( void ) {
DBG ( "HEAP discarding allocated blocks in [%x,%x)\n",
heap_ptr, heap_end );
heap_ptr = heap_end;
}
/*
* Resize a heap block
*
*/
void * erealloc ( void *ptr, size_t size ) {
struct heap_block *old_block;
size_t old_size;
unsigned int old_align;
physaddr_t new_addr;
size_t move_size;
/* Get descriptor of the old block */
old_block = ( struct heap_block * )
( ptr - offsetof ( struct heap_block, data ) );
old_size = old_block->size;
old_align = old_block->align;
/* Check that allocation is going to succeed */
new_addr = block_alloc_addr ( block_free_addr ( old_size ),
size, old_align );
if ( new_addr < heap_start ) {
DBG ( "HEAP no space for %x bytes (alignment %d) in [%x,%x)\n",
size, align, heap_start, block_free_addr ( old_size ) );
return NULL;
}
/* Free the old block */
efree ( ptr );
/* Move the data. Do this *before* allocating the new block,
* because the new block's descriptor may overwrite the old
* block's data, if the new block is smaller than the old
* block.
*/
move_size = size + sizeof ( struct heap_block );
if ( old_size < move_size )
move_size = old_size;
memmove ( phys_to_virt ( new_addr ), old_block, move_size );
/* Allocate the new block. This must succeed, because we
* already checked that there was sufficient space.
*/
ptr = emalloc ( size, old_align );
assert ( ptr != NULL );
return ptr;
}
INIT_FN ( INIT_HEAP, init_heap, efree_all, NULL );
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