[pcbios] Restrict external memory allocations to the low 4GB

When running the 64-bit BIOS version of iPXE, restrict external memory
allocations to the low 4GB to ensure that allocations (such as for
initrds) fall within our identity-mapped memory region, and will be
accessible to the potentially 32-bit operating system.

Move largest_memblock() back to memtop_umalloc.c, since this change
imposes a restriction that applies only to BIOS builds.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 0 insertions, 85 deletions

diff --git a/src/core/memblock.c b/src/core/memblock.c
deleted file mode 100644
index aecddc22..00000000
--- a/src/core/memblock.c
+++ /dev/null
@@ -1,85 +0,0 @@
-/*
- * Copyright (C) 2012 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 (at your option) 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
- *
- * Largest memory block
- *
- */
-
-#include <stdint.h>
-#include <ipxe/uaccess.h>
-#include <ipxe/io.h>
-#include <ipxe/memblock.h>
-
-/**
- * Find largest usable memory region
- *
- * @ret start		Start of region
- * @ret len		Length of region
- */
-size_t largest_memblock ( userptr_t *start ) {
-	struct memory_map memmap;
-	struct memory_region *region;
-	physaddr_t max = ~( ( physaddr_t ) 0 );
-	physaddr_t region_start;
-	physaddr_t region_end;
-	size_t region_len;
-	unsigned int i;
-	size_t len = 0;
-
-	/* Avoid returning uninitialised data on error */
-	*start = UNULL;
-
-	/* Scan through all memory regions */
-	get_memmap ( &memmap );
-	for ( i = 0 ; i < memmap.count ; i++ ) {
-		region = &memmap.regions[i];
-		DBG ( "Considering [%llx,%llx)\n", region->start, region->end );
-
-		/* Truncate block to maximum physical address */
-		if ( region->start > max ) {
-			DBG ( "...starts after maximum address %lx\n", max );
-			continue;
-		}
-		region_start = region->start;
-		if ( region->end > max ) {
-			DBG ( "...end truncated to maximum address %lx\n", max);
-			region_end = 0; /* =max, given the wraparound */
-		} else {
-			region_end = region->end;
-		}
-		region_len = ( region_end - region_start );
-
-		/* Use largest block */
-		if ( region_len > len ) {
-			DBG ( "...new best block found\n" );
-			*start = phys_to_user ( region_start );
-			len = region_len;
-		}
-	}
-
-	return len;
-}