1 files changed, 400 insertions, 0 deletions
diff --git a/mm/bootmem.c b/mm/bootmem.c
new file mode 100644
index 00000000000..260e703850d
--- /dev/null
+++ b/mm/bootmem.c
@@ -0,0 +1,400 @@
+/*
+ *  linux/mm/bootmem.c
+ *
+ *  Copyright (C) 1999 Ingo Molnar
+ *  Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999
+ *
+ *  simple boot-time physical memory area allocator and
+ *  free memory collector. It's used to deal with reserved
+ *  system memory and memory holes as well.
+ */
+
+#include <linux/mm.h>
+#include <linux/kernel_stat.h>
+#include <linux/swap.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/bootmem.h>
+#include <linux/mmzone.h>
+#include <linux/module.h>
+#include <asm/dma.h>
+#include <asm/io.h>
+#include "internal.h"
+
+/*
+ * Access to this subsystem has to be serialized externally. (this is
+ * true for the boot process anyway)
+ */
+unsigned long max_low_pfn;
+unsigned long min_low_pfn;
+unsigned long max_pfn;
+
+EXPORT_SYMBOL(max_pfn);		/* This is exported so
+				 * dma_get_required_mask(), which uses
+				 * it, can be an inline function */
+
+/* return the number of _pages_ that will be allocated for the boot bitmap */
+unsigned long __init bootmem_bootmap_pages (unsigned long pages)
+{
+	unsigned long mapsize;
+
+	mapsize = (pages+7)/8;
+	mapsize = (mapsize + ~PAGE_MASK) & PAGE_MASK;
+	mapsize >>= PAGE_SHIFT;
+
+	return mapsize;
+}
+
+/*
+ * Called once to set up the allocator itself.
+ */
+static unsigned long __init init_bootmem_core (pg_data_t *pgdat,
+	unsigned long mapstart, unsigned long start, unsigned long end)
+{
+	bootmem_data_t *bdata = pgdat->bdata;
+	unsigned long mapsize = ((end - start)+7)/8;
+
+	pgdat->pgdat_next = pgdat_list;
+	pgdat_list = pgdat;
+
+	mapsize = (mapsize + (sizeof(long) - 1UL)) & ~(sizeof(long) - 1UL);
+	bdata->node_bootmem_map = phys_to_virt(mapstart << PAGE_SHIFT);
+	bdata->node_boot_start = (start << PAGE_SHIFT);
+	bdata->node_low_pfn = end;
+
+	/*
+	 * Initially all pages are reserved - setup_arch() has to
+	 * register free RAM areas explicitly.
+	 */
+	memset(bdata->node_bootmem_map, 0xff, mapsize);
+
+	return mapsize;
+}
+
+/*
+ * Marks a particular physical memory range as unallocatable. Usable RAM
+ * might be used for boot-time allocations - or it might get added
+ * to the free page pool later on.
+ */
+static void __init reserve_bootmem_core(bootmem_data_t *bdata, unsigned long addr, unsigned long size)
+{
+	unsigned long i;
+	/*
+	 * round up, partially reserved pages are considered
+	 * fully reserved.
+	 */
+	unsigned long sidx = (addr - bdata->node_boot_start)/PAGE_SIZE;
+	unsigned long eidx = (addr + size - bdata->node_boot_start + 
+							PAGE_SIZE-1)/PAGE_SIZE;
+	unsigned long end = (addr + size + PAGE_SIZE-1)/PAGE_SIZE;
+
+	BUG_ON(!size);
+	BUG_ON(sidx >= eidx);
+	BUG_ON((addr >> PAGE_SHIFT) >= bdata->node_low_pfn);
+	BUG_ON(end > bdata->node_low_pfn);
+
+	for (i = sidx; i < eidx; i++)
+		if (test_and_set_bit(i, bdata->node_bootmem_map)) {
+#ifdef CONFIG_DEBUG_BOOTMEM
+			printk("hm, page %08lx reserved twice.\n", i*PAGE_SIZE);
+#endif
+		}
+}
+
+static void __init free_bootmem_core(bootmem_data_t *bdata, unsigned long addr, unsigned long size)
+{
+	unsigned long i;
+	unsigned long start;
+	/*
+	 * round down end of usable mem, partially free pages are
+	 * considered reserved.
+	 */
+	unsigned long sidx;
+	unsigned long eidx = (addr + size - bdata->node_boot_start)/PAGE_SIZE;
+	unsigned long end = (addr + size)/PAGE_SIZE;
+
+	BUG_ON(!size);
+	BUG_ON(end > bdata->node_low_pfn);
+
+	if (addr < bdata->last_success)
+		bdata->last_success = addr;
+
+	/*
+	 * Round up the beginning of the address.
+	 */
+	start = (addr + PAGE_SIZE-1) / PAGE_SIZE;
+	sidx = start - (bdata->node_boot_start/PAGE_SIZE);
+
+	for (i = sidx; i < eidx; i++) {
+		if (unlikely(!test_and_clear_bit(i, bdata->node_bootmem_map)))
+			BUG();
+	}
+}
+
+/*
+ * We 'merge' subsequent allocations to save space. We might 'lose'
+ * some fraction of a page if allocations cannot be satisfied due to
+ * size constraints on boxes where there is physical RAM space
+ * fragmentation - in these cases (mostly large memory boxes) this
+ * is not a problem.
+ *
+ * On low memory boxes we get it right in 100% of the cases.
+ *
+ * alignment has to be a power of 2 value.
+ *
+ * NOTE:  This function is _not_ reentrant.
+ */
+static void * __init
+__alloc_bootmem_core(struct bootmem_data *bdata, unsigned long size,
+		unsigned long align, unsigned long goal)
+{
+	unsigned long offset, remaining_size, areasize, preferred;
+	unsigned long i, start = 0, incr, eidx;
+	void *ret;
+
+	if(!size) {
+		printk("__alloc_bootmem_core(): zero-sized request\n");
+		BUG();
+	}
+	BUG_ON(align & (align-1));
+
+	eidx = bdata->node_low_pfn - (bdata->node_boot_start >> PAGE_SHIFT);
+	offset = 0;
+	if (align &&
+	    (bdata->node_boot_start & (align - 1UL)) != 0)
+		offset = (align - (bdata->node_boot_start & (align - 1UL)));
+	offset >>= PAGE_SHIFT;
+
+	/*
+	 * We try to allocate bootmem pages above 'goal'
+	 * first, then we try to allocate lower pages.
+	 */
+	if (goal && (goal >= bdata->node_boot_start) && 
+	    ((goal >> PAGE_SHIFT) < bdata->node_low_pfn)) {
+		preferred = goal - bdata->node_boot_start;
+
+		if (bdata->last_success >= preferred)
+			preferred = bdata->last_success;
+	} else
+		preferred = 0;
+
+	preferred = ((preferred + align - 1) & ~(align - 1)) >> PAGE_SHIFT;
+	preferred += offset;
+	areasize = (size+PAGE_SIZE-1)/PAGE_SIZE;
+	incr = align >> PAGE_SHIFT ? : 1;
+
+restart_scan:
+	for (i = preferred; i < eidx; i += incr) {
+		unsigned long j;
+		i = find_next_zero_bit(bdata->node_bootmem_map, eidx, i);
+		i = ALIGN(i, incr);
+		if (test_bit(i, bdata->node_bootmem_map))
+			continue;
+		for (j = i + 1; j < i + areasize; ++j) {
+			if (j >= eidx)
+				goto fail_block;
+			if (test_bit (j, bdata->node_bootmem_map))
+				goto fail_block;
+		}
+		start = i;
+		goto found;
+	fail_block:
+		i = ALIGN(j, incr);
+	}
+
+	if (preferred > offset) {
+		preferred = offset;
+		goto restart_scan;
+	}
+	return NULL;
+
+found:
+	bdata->last_success = start << PAGE_SHIFT;
+	BUG_ON(start >= eidx);
+
+	/*
+	 * Is the next page of the previous allocation-end the start
+	 * of this allocation's buffer? If yes then we can 'merge'
+	 * the previous partial page with this allocation.
+	 */
+	if (align < PAGE_SIZE &&
+	    bdata->last_offset && bdata->last_pos+1 == start) {
+		offset = (bdata->last_offset+align-1) & ~(align-1);
+		BUG_ON(offset > PAGE_SIZE);
+		remaining_size = PAGE_SIZE-offset;
+		if (size < remaining_size) {
+			areasize = 0;
+			/* last_pos unchanged */
+			bdata->last_offset = offset+size;
+			ret = phys_to_virt(bdata->last_pos*PAGE_SIZE + offset +
+						bdata->node_boot_start);
+		} else {
+			remaining_size = size - remaining_size;
+			areasize = (remaining_size+PAGE_SIZE-1)/PAGE_SIZE;
+			ret = phys_to_virt(bdata->last_pos*PAGE_SIZE + offset +
+						bdata->node_boot_start);
+			bdata->last_pos = start+areasize-1;
+			bdata->last_offset = remaining_size;
+		}
+		bdata->last_offset &= ~PAGE_MASK;
+	} else {
+		bdata->last_pos = start + areasize - 1;
+		bdata->last_offset = size & ~PAGE_MASK;
+		ret = phys_to_virt(start * PAGE_SIZE + bdata->node_boot_start);
+	}
+
+	/*
+	 * Reserve the area now:
+	 */
+	for (i = start; i < start+areasize; i++)
+		if (unlikely(test_and_set_bit(i, bdata->node_bootmem_map)))
+			BUG();
+	memset(ret, 0, size);
+	return ret;
+}
+
+static unsigned long __init free_all_bootmem_core(pg_data_t *pgdat)
+{
+	struct page *page;
+	bootmem_data_t *bdata = pgdat->bdata;
+	unsigned long i, count, total = 0;
+	unsigned long idx;
+	unsigned long *map; 
+	int gofast = 0;
+
+	BUG_ON(!bdata->node_bootmem_map);
+
+	count = 0;
+	/* first extant page of the node */
+	page = virt_to_page(phys_to_virt(bdata->node_boot_start));
+	idx = bdata->node_low_pfn - (bdata->node_boot_start >> PAGE_SHIFT);
+	map = bdata->node_bootmem_map;
+	/* Check physaddr is O(LOG2(BITS_PER_LONG)) page aligned */
+	if (bdata->node_boot_start == 0 ||
+	    ffs(bdata->node_boot_start) - PAGE_SHIFT > ffs(BITS_PER_LONG))
+		gofast = 1;
+	for (i = 0; i < idx; ) {
+		unsigned long v = ~map[i / BITS_PER_LONG];
+		if (gofast && v == ~0UL) {
+			int j, order;
+
+			count += BITS_PER_LONG;
+			__ClearPageReserved(page);
+			order = ffs(BITS_PER_LONG) - 1;
+			set_page_refs(page, order);
+			for (j = 1; j < BITS_PER_LONG; j++) {
+				if (j + 16 < BITS_PER_LONG)
+					prefetchw(page + j + 16);
+				__ClearPageReserved(page + j);
+			}
+			__free_pages(page, order);
+			i += BITS_PER_LONG;
+			page += BITS_PER_LONG;
+		} else if (v) {
+			unsigned long m;
+			for (m = 1; m && i < idx; m<<=1, page++, i++) {
+				if (v & m) {
+					count++;
+					__ClearPageReserved(page);
+					set_page_refs(page, 0);
+					__free_page(page);
+				}
+			}
+		} else {
+			i+=BITS_PER_LONG;
+			page += BITS_PER_LONG;
+		}
+	}
+	total += count;
+
+	/*
+	 * Now free the allocator bitmap itself, it's not
+	 * needed anymore:
+	 */
+	page = virt_to_page(bdata->node_bootmem_map);
+	count = 0;
+	for (i = 0; i < ((bdata->node_low_pfn-(bdata->node_boot_start >> PAGE_SHIFT))/8 + PAGE_SIZE-1)/PAGE_SIZE; i++,page++) {
+		count++;
+		__ClearPageReserved(page);
+		set_page_count(page, 1);
+		__free_page(page);
+	}
+	total += count;
+	bdata->node_bootmem_map = NULL;
+
+	return total;
+}
+
+unsigned long __init init_bootmem_node (pg_data_t *pgdat, unsigned long freepfn, unsigned long startpfn, unsigned long endpfn)
+{
+	return(init_bootmem_core(pgdat, freepfn, startpfn, endpfn));
+}
+
+void __init reserve_bootmem_node (pg_data_t *pgdat, unsigned long physaddr, unsigned long size)
+{
+	reserve_bootmem_core(pgdat->bdata, physaddr, size);
+}
+
+void __init free_bootmem_node (pg_data_t *pgdat, unsigned long physaddr, unsigned long size)
+{
+	free_bootmem_core(pgdat->bdata, physaddr, size);
+}
+
+unsigned long __init free_all_bootmem_node (pg_data_t *pgdat)
+{
+	return(free_all_bootmem_core(pgdat));
+}
+
+unsigned long __init init_bootmem (unsigned long start, unsigned long pages)
+{
+	max_low_pfn = pages;
+	min_low_pfn = start;
+	return(init_bootmem_core(NODE_DATA(0), start, 0, pages));
+}
+
+#ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODE
+void __init reserve_bootmem (unsigned long addr, unsigned long size)
+{
+	reserve_bootmem_core(NODE_DATA(0)->bdata, addr, size);
+}
+#endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */
+
+void __init free_bootmem (unsigned long addr, unsigned long size)
+{
+	free_bootmem_core(NODE_DATA(0)->bdata, addr, size);
+}
+
+unsigned long __init free_all_bootmem (void)
+{
+	return(free_all_bootmem_core(NODE_DATA(0)));
+}
+
+void * __init __alloc_bootmem (unsigned long size, unsigned long align, unsigned long goal)
+{
+	pg_data_t *pgdat = pgdat_list;
+	void *ptr;
+
+	for_each_pgdat(pgdat)
+		if ((ptr = __alloc_bootmem_core(pgdat->bdata, size,
+						align, goal)))
+			return(ptr);
+
+	/*
+	 * Whoops, we cannot satisfy the allocation request.
+	 */
+	printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
+	panic("Out of memory");
+	return NULL;
+}
+
+void * __init __alloc_bootmem_node (pg_data_t *pgdat, unsigned long size, unsigned long align, unsigned long goal)
+{
+	void *ptr;
+
+	ptr = __alloc_bootmem_core(pgdat->bdata, size, align, goal);
+	if (ptr)
+		return (ptr);
+
+	return __alloc_bootmem(size, align, goal);
+}
+