/* * 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/init.h> #include <linux/pfn.h> #include <linux/bootmem.h> #include <linux/module.h> #include <asm/bug.h> #include <asm/io.h> #include <asm/processor.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_UNUSED_SYMBOL(max_pfn); /* June 2006 */ static LIST_HEAD(bdata_list); #ifdef CONFIG_CRASH_DUMP /* * If we have booted due to a crash, max_pfn will be a very low value. We need * to know the amount of memory that the previous kernel used. */ unsigned long saved_max_pfn; #endif /* 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; } /* * link bdata in order */ static void __init link_bootmem(bootmem_data_t *bdata) { bootmem_data_t *ent; if (list_empty(&bdata_list)) { list_add(&bdata->list, &bdata_list); return; } /* insert in order */ list_for_each_entry(ent, &bdata_list, list) { if (bdata->node_boot_start < ent->node_boot_start) { list_add_tail(&bdata->list, &ent->list); return; } } list_add_tail(&bdata->list, &bdata_list); } /* * Given an initialised bdata, it returns the size of the boot bitmap */ static unsigned long __init get_mapsize(bootmem_data_t *bdata) { unsigned long mapsize; unsigned long start = PFN_DOWN(bdata->node_boot_start); unsigned long end = bdata->node_low_pfn; mapsize = ((end - start) + 7) / 8; return ALIGN(mapsize, sizeof(long)); } /* * 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; bdata->node_bootmem_map = phys_to_virt(PFN_PHYS(mapstart)); bdata->node_boot_start = PFN_PHYS(start); bdata->node_low_pfn = end; link_bootmem(bdata); /* * Initially all pages are reserved - setup_arch() has to * register free RAM areas explicitly. */ mapsize = get_mapsize(bdata); 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 sidx, eidx; unsigned long i; /* * round up, partially reserved pages are considered * fully reserved. */ BUG_ON(!size); BUG_ON(PFN_DOWN(addr) >= bdata->node_low_pfn); BUG_ON(PFN_UP(addr + size) > bdata->node_low_pfn); sidx = PFN_DOWN(addr - bdata->node_boot_start); eidx = PFN_UP(addr + size - bdata->node_boot_start); 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 sidx, eidx; unsigned long i; /* * round down end of usable mem, partially free pages are * considered reserved. */ BUG_ON(!size); BUG_ON(PFN_DOWN(addr + size) > bdata->node_low_pfn); if (addr < bdata->last_success) bdata->last_success = addr; /* * Round up the beginning of the address. */ sidx = PFN_UP(addr) - PFN_DOWN(bdata->node_boot_start); eidx = PFN_DOWN(addr + size - bdata->node_boot_start); 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. */ void * __init __alloc_bootmem_core(struct bootmem_data *bdata, unsigned long size, unsigned long align, unsigned long goal, unsigned long limit) { unsigned long offset, remaining_size, areasize, preferred; unsigned long i, start = 0, incr, eidx, end_pfn; void *ret; if (!size) { printk("__alloc_bootmem_core(): zero-sized request\n"); BUG(); } BUG_ON(align & (align-1)); if (limit && bdata->node_boot_start >= limit) return NULL; end_pfn = bdata->node_low_pfn; limit = PFN_DOWN(limit); if (limit && end_pfn > limit) end_pfn = limit; eidx = end_pfn - PFN_DOWN(bdata->node_boot_start); offset = 0; if (align && (bdata->node_boot_start & (align - 1UL)) != 0) offset = align - (bdata->node_boot_start & (align - 1UL)); offset = PFN_DOWN(offset); /* * We try to allocate bootmem pages above 'goal' * first, then we try to allocate lower pages. */ if (goal && goal >= bdata->node_boot_start && PFN_DOWN(goal) < end_pfn) { preferred = goal - bdata->node_boot_start; if (bdata->last_success >= preferred) if (!limit || (limit && limit > bdata->last_success)) preferred = bdata->last_success; } else preferred = 0; preferred = PFN_DOWN(ALIGN(preferred, align)) + 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 (i >= eidx) break; 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 = PFN_PHYS(start); 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 = ALIGN(bdata->last_offset, align); 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; unsigned long pfn; 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 */ pfn = PFN_DOWN(bdata->node_boot_start); idx = bdata->node_low_pfn - pfn; 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 order; page = pfn_to_page(pfn); count += BITS_PER_LONG; order = ffs(BITS_PER_LONG) - 1; __free_pages_bootmem(page, order); i += BITS_PER_LONG; page += BITS_PER_LONG; } else if (v) { unsigned long m; page = pfn_to_page(pfn); for (m = 1; m && i < idx; m<<=1, page++, i++) { if (v & m) { count++; __free_pages_bootmem(page, 0); } } } else { i += BITS_PER_LONG; } pfn += 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; idx = (get_mapsize(bdata) + PAGE_SIZE-1) >> PAGE_SHIFT; for (i = 0; i < idx; i++, page++) { __free_pages_bootmem(page, 0); count++; } 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_nopanic(unsigned long size, unsigned long align, unsigned long goal) { bootmem_data_t *bdata; void *ptr; list_for_each_entry(bdata, &bdata_list, list) { ptr = __alloc_bootmem_core(bdata, size, align, goal, 0); if (ptr) return ptr; } return NULL; } void * __init __alloc_bootmem(unsigned long size, unsigned long align, unsigned long goal) { void *mem = __alloc_bootmem_nopanic(size,align,goal); if (mem) return mem; /* * 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, 0); if (ptr) return ptr; return __alloc_bootmem(size, align, goal); } #ifndef ARCH_LOW_ADDRESS_LIMIT #define ARCH_LOW_ADDRESS_LIMIT 0xffffffffUL #endif void * __init __alloc_bootmem_low(unsigned long size, unsigned long align, unsigned long goal) { bootmem_data_t *bdata; void *ptr; list_for_each_entry(bdata, &bdata_list, list) { ptr = __alloc_bootmem_core(bdata, size, align, goal, ARCH_LOW_ADDRESS_LIMIT); if (ptr) return ptr; } /* * Whoops, we cannot satisfy the allocation request. */ printk(KERN_ALERT "low bootmem alloc of %lu bytes failed!\n", size); panic("Out of low memory"); return NULL; } void * __init __alloc_bootmem_low_node(pg_data_t *pgdat, unsigned long size, unsigned long align, unsigned long goal) { return __alloc_bootmem_core(pgdat->bdata, size, align, goal, ARCH_LOW_ADDRESS_LIMIT); }