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Allocate heap at first usage, rather than assuming we can fit it in

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below _text.  This should help with the gPXE-on-gPXE-via-PXE case.
This commit is contained in:
Michael Brown 2007-07-05 22:30:34 +01:00
parent b3ca73c303
commit fbda4837b0
1 changed files with 65 additions and 10 deletions
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75
src/arch/i386/core/umalloc.c
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@ -23,8 +23,11 @@
*
*/
#include <limits.h>
#include <errno.h>
#include <gpxe/uaccess.h>
#include <gpxe/hidemem.h>
#include <gpxe/memmap.h>
#include <gpxe/umalloc.h>
/** Alignment of external allocated memory */
@ -36,9 +39,6 @@
/** Start of Etherboot text, as defined by the linker */
extern char _text[];
/** Top of allocatable memory */
#define TOP ( virt_to_user ( _text ) )
/** An external memory block */
struct external_memory {
/** Size of this memory block (excluding this header) */
@ -47,11 +47,63 @@ struct external_memory {
int used;
};
/** Current lowest allocated block
/** Top of heap */
static userptr_t top = UNULL;
/** Bottom of heap (current lowest allocated block) */
static userptr_t bottom = UNULL;
/**
* Initialise external heap
*
* A value of UNULL indicates that no blocks are currently allocated.
* @ret rc Return status code
*/
userptr_t bottom = UNULL;
static int init_eheap ( void ) {
struct memory_map memmap;
unsigned long heap_size = 0;
unsigned int i;
DBG ( "Allocating external heap\n" );
get_memmap ( &memmap );
for ( i = 0 ; i < memmap.count ; i++ ) {
struct memory_region *region = &memmap.regions[i];
unsigned long r_start, r_end;
unsigned long r_size;
DBG ( "Considering [%llx,%llx)\n", region->start, region->end);
/* Truncate block to 4GB */
if ( region->start > UINT_MAX ) {
DBG ( "...starts after 4GB\n" );
continue;
}
r_start = region->start;
if ( region->end > UINT_MAX ) {
DBG ( "...end truncated to 4GB\n" );
r_end = 0; /* =4GB, given the wraparound */
} else {
r_end = region->end;
}
/* Use largest block */
r_size = ( r_end - r_start );
if ( r_size > heap_size ) {
DBG ( "...new best block found\n" );
top = bottom = phys_to_user ( r_end );
heap_size = r_size;
}
}
if ( ! top ) {
DBG ( "No external heap available\n" );
return -ENOMEM;
}
DBG ( "External heap grows downwards from %lx\n",
user_to_phys ( top, 0 ) );
return 0;
}
/**
* Collect free blocks
@ -61,7 +113,7 @@ static void ecollect_free ( void ) {
struct external_memory extmem;
/* Walk the free list and collect empty blocks */
while ( bottom != TOP ) {
while ( bottom != top ) {
copy_from_user ( &extmem, bottom, -sizeof ( extmem ),
sizeof ( extmem ) );
if ( extmem.used )
@ -87,10 +139,13 @@ userptr_t urealloc ( userptr_t ptr, size_t new_size ) {
struct external_memory extmem;
userptr_t new = ptr;
size_t align;
int rc;
/* Initialise external memory allocator if necessary */
if ( ! bottom )
bottom = TOP;
if ( ! top ) {
if ( ( rc = init_eheap() ) != 0 )
return rc;
}
/* Get block properties into extmem */
if ( ptr && ( ptr != UNOWHERE ) ) {
@ -140,7 +195,7 @@ userptr_t urealloc ( userptr_t ptr, size_t new_size ) {
/* Collect any free blocks and update hidden memory region */
ecollect_free();
hide_region ( EXTMEM, user_to_phys ( bottom, -sizeof ( extmem ) ),
user_to_phys ( TOP, 0 ) );
user_to_phys ( top, 0 ) );
return ( new_size ? new : UNOWHERE );
}