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Tidied up init_heap()
This commit is contained in:
Michael Brown
parent
f0d048bf91
commit
42250e9b1a
133
src/core/heap.c
133
src/core/heap.c
@ -8,88 +8,75 @@ struct heap_block {
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char data[0];
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};
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size_t heap_ptr, heap_top, heap_bot;
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/* Linker symbols */
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extern char _text[];
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extern char _end[];
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#define _virt_start 0
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static unsigned long heap_start, heap_end, heap_ptr;
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static void init_heap(void)
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{
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size_t size;
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size_t start, end;
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unsigned i;
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/* Find the largest contiguous area of memory that
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* I can use for the heap, which is organized as
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* a stack that grows backwards through memory.
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*/
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/*
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* Find the largest contiguous area of memory that I can use for the
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* heap.
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*
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*/
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static void init_heap ( void ) {
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unsigned int i;
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unsigned long eb_start, eb_end;
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unsigned long size;
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/* If I have virtual address that do not equal physical addresses
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* there is a change I will try to use memory from both sides of
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* the virtual address space simultaneously, which can cause all kinds
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* of interesting problems.
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* Avoid it by logically extending etherboot. Once I know that relocation
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* works I can just start the virtual address space at 0, and this problem goes
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* away so that is probably a better solution.
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*/
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#if 0
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start = virt_to_phys(_text);
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#else
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/* segment wrap around is nasty don't chance it. */
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start = virt_to_phys(_virt_start);
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#endif
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end = virt_to_phys(_end);
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size = 0;
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for(i = 0; i < meminfo.map_count; i++) {
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unsigned long r_start, r_end;
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if (meminfo.map[i].type != E820_RAM)
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/* Region occupied by Etherboot */
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eb_start = virt_to_phys ( _text );
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eb_end = virt_to_phys ( _end );
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for ( i = 0 ; i < meminfo.map_count ; i++ ) {
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unsigned long r_start, r_end, r_size;
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unsigned long pre_eb, post_eb;
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/* Get start and end addresses of the region */
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if ( meminfo.map[i].type != E820_RAM )
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continue;
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if (meminfo.map[i].addr > ULONG_MAX)
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if ( meminfo.map[i].addr > ULONG_MAX )
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continue;
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if (meminfo.map[i].size > ULONG_MAX)
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continue;
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r_start = meminfo.map[i].addr;
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r_end = r_start + meminfo.map[i].size;
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if (r_end < r_start) {
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if ( r_start + meminfo.map[i].size > ULONG_MAX ) {
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r_end = ULONG_MAX;
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} else {
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r_end = r_start + meminfo.map[i].size;
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}
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/* Handle areas that overlap etherboot */
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if ((end > r_start) && (start < r_end)) {
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/* Etherboot completely covers the region */
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if ((start <= r_start) && (end >= r_end))
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continue;
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/* Etherboot is completely contained in the region */
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if ((start > r_start) && (end < r_end)) {
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/* keep the larger piece */
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if ((r_end - end) >= (r_start - start)) {
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r_start = end;
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}
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else {
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r_end = start;
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}
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}
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/* Etherboot covers one end of the region.
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* Shrink the region.
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*/
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else if (end >= r_end) {
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r_end = start;
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}
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else if (start <= r_start) {
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r_start = end;
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/* Avoid overlap with Etherboot. When Etherboot is
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* completely contained within the region, choose the
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* larger of the two remaining portions.
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*/
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if ( ( eb_start < r_end ) && ( eb_end > r_start ) ) {
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pre_eb = ( eb_start > r_start ) ?
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( eb_start - r_start ) : 0;
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post_eb = ( r_end > eb_end ) ?
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( r_end - eb_end ) : 0;
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if ( pre_eb > post_eb ) {
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r_end = eb_start;
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} else {
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r_start = eb_end;
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}
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}
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/* If two areas are the size prefer the greater address */
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if (((r_end - r_start) > size) ||
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(((r_end - r_start) == size) && (r_start > heap_top))) {
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size = r_end - r_start;
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heap_top = r_start;
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heap_bot = r_end;
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/* Use the biggest region. Where two regions are the
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* same size, use the later region. (Provided that
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* the memory map is laid out in a sensible order,
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* this should give us the higher region.)
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*/
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r_size = r_end - r_start;
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if ( r_size >= size ) {
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heap_start = r_start;
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heap_end = r_end;
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size = r_size;
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}
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}
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if (size == 0) {
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printf("init_heap: No heap found.\n");
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exit(1);
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}
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heap_ptr = heap_bot;
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ASSERT ( size != 0 );
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heap_ptr = heap_end;
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}
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/*
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@ -104,7 +91,7 @@ void * emalloc ( size_t size, unsigned int align ) {
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addr = ( ( ( heap_ptr - size ) & ~( align - 1 ) )
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- sizeof ( struct heap_block ) );
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if ( addr < heap_top ) {
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if ( addr < heap_start ) {
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return NULL;
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}
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@ -119,7 +106,7 @@ void * emalloc ( size_t size, unsigned int align ) {
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*
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*/
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void * emalloc_all ( size_t *size ) {
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*size = heap_ptr - heap_top - sizeof ( struct heap_block );
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*size = heap_ptr - heap_start - sizeof ( struct heap_block );
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return emalloc ( *size, sizeof ( void * ) );
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}
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@ -136,7 +123,7 @@ void efree ( void *ptr ) {
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( ptr - offsetof ( struct heap_block, data ) );
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heap_ptr += block->size;
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ASSERT ( heap_ptr <= heap_bot );
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ASSERT ( heap_ptr <= heap_end );
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}
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/*
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@ -144,7 +131,7 @@ void efree ( void *ptr ) {
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*
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*/
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void efree_all ( void ) {
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heap_ptr = heap_bot;
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heap_ptr = heap_end;
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}
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INIT_FN ( INIT_HEAP, init_heap, efree_all, NULL );
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