// SPDX-License-Identifier: GPL-2.0 /* * bootmem - A boot-time physical memory allocator and configurator * * Copyright (C) 1999 Ingo Molnar * 1999 Kanoj Sarcar, SGI * 2008 Johannes Weiner * * Access to this subsystem has to be serialized externally (which is true * for the boot process anyway). */ #include <linux/init.h> #include <linux/pfn.h> #include <linux/slab.h> #include <linux/export.h> #include <linux/kmemleak.h> #include <linux/range.h> #include <linux/bug.h> #include <linux/io.h> #include <linux/bootmem.h> #include "internal.h" /** * DOC: bootmem overview * * Bootmem is a boot-time physical memory allocator and configurator. * * It is used early in the boot process before the page allocator is * set up. * * Bootmem is based on the most basic of allocators, a First Fit * allocator which uses a bitmap to represent memory. If a bit is 1, * the page is allocated and 0 if unallocated. To satisfy allocations * of sizes smaller than a page, the allocator records the Page Frame * Number (PFN) of the last allocation and the offset the allocation * ended at. Subsequent small allocations are merged together and * stored on the same page. * * The information used by the bootmem allocator is represented by * :c:type:`struct bootmem_data`. An array to hold up to %MAX_NUMNODES * such structures is statically allocated and then it is discarded * when the system initialization completes. Each entry in this array * corresponds to a node with memory. For UMA systems only entry 0 is * used. * * The bootmem allocator is initialized during early architecture * specific setup. Each architecture is required to supply a * :c:func:`setup_arch` function which, among other tasks, is * responsible for acquiring the necessary parameters to initialise * the boot memory allocator. These parameters define limits of usable * physical memory: * * * @min_low_pfn - the lowest PFN that is available in the system * * @max_low_pfn - the highest PFN that may be addressed by low * memory (%ZONE_NORMAL) * * @max_pfn - the last PFN available to the system. * * After those limits are determined, the :c:func:`init_bootmem` or * :c:func:`init_bootmem_node` function should be called to initialize * the bootmem allocator. The UMA case should use the `init_bootmem` * function. It will initialize ``contig_page_data`` structure that * represents the only memory node in the system. In the NUMA case the * `init_bootmem_node` function should be called to initialize the * bootmem allocator for each node. * * Once the allocator is set up, it is possible to use either single * node or NUMA variant of the allocation APIs. */ #ifndef CONFIG_NEED_MULTIPLE_NODES struct pglist_data __refdata contig_page_data = { .bdata = &bootmem_node_data[0] }; EXPORT_SYMBOL(contig_page_data); #endif unsigned long max_low_pfn; unsigned long min_low_pfn; unsigned long max_pfn; unsigned long long max_possible_pfn; bootmem_data_t bootmem_node_data[MAX_NUMNODES] __initdata; static struct list_head bdata_list __initdata = LIST_HEAD_INIT(bdata_list); static int bootmem_debug; static int __init bootmem_debug_setup(char *buf) { bootmem_debug = 1; return 0; } early_param("bootmem_debug", bootmem_debug_setup); #define bdebug(fmt, args...) ({ \ if (unlikely(bootmem_debug)) \ pr_info("bootmem::%s " fmt, \ __func__, ## args); \ }) static unsigned long __init bootmap_bytes(unsigned long pages) { unsigned long bytes = DIV_ROUND_UP(pages, BITS_PER_BYTE); return ALIGN(bytes, sizeof(long)); } /** * bootmem_bootmap_pages - calculate bitmap size in pages * @pages: number of pages the bitmap has to represent * * Return: the number of pages needed to hold the bitmap. */ unsigned long __init bootmem_bootmap_pages(unsigned long pages) { unsigned long bytes = bootmap_bytes(pages); return PAGE_ALIGN(bytes) >> PAGE_SHIFT; } /* * link bdata in order */ static void __init link_bootmem(bootmem_data_t *bdata) { bootmem_data_t *ent; list_for_each_entry(ent, &bdata_list, list) { if (bdata->node_min_pfn < ent->node_min_pfn) { list_add_tail(&bdata->list, &ent->list); return; } } list_add_tail(&bdata->list, &bdata_list); } /* * Called once to set up the allocator itself. */ static unsigned long __init init_bootmem_core(bootmem_data_t *bdata, unsigned long mapstart, unsigned long start, unsigned long end) { unsigned long mapsize; mminit_validate_memmodel_limits(&start, &end); bdata->node_bootmem_map = phys_to_virt(PFN_PHYS(mapstart)); bdata->node_min_pfn = start; bdata->node_low_pfn = end; link_bootmem(bdata); /* * Initially all pages are reserved - setup_arch() has to * register free RAM areas explicitly. */ mapsize = bootmap_bytes(end - start); memset(bdata->node_bootmem_map, 0xff, mapsize); bdebug("nid=%td start=%lx map=%lx end=%lx mapsize=%lx\n", bdata - bootmem_node_data, start, mapstart, end, mapsize); return mapsize; } /** * init_bootmem_node - register a node as boot memory * @pgdat: node to register * @freepfn: pfn where the bitmap for this node is to be placed * @startpfn: first pfn on the node * @endpfn: first pfn after the node * * Return: the number of bytes needed to hold the bitmap for this node. */ unsigned long __init init_bootmem_node(pg_data_t *pgdat, unsigned long freepfn, unsigned long startpfn, unsigned long endpfn) { return init_bootmem_core(pgdat->bdata, freepfn, startpfn, endpfn); } /** * init_bootmem - register boot memory * @start: pfn where the bitmap is to be placed * @pages: number of available physical pages * * Return: the number of bytes needed to hold the bitmap. */ 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)->bdata, start, 0, pages); } void __init free_bootmem_late(unsigned long physaddr, unsigned long size) { unsigned long cursor, end; kmemleak_free_part_phys(physaddr, size); cursor = PFN_UP(physaddr); end = PFN_DOWN(physaddr + size); for (; cursor < end; cursor++) { __free_pages_bootmem(pfn_to_page(cursor), cursor, 0); totalram_pages++; } } static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata) { struct page *page; unsigned long *map, start, end, pages, cur, count = 0; if (!bdata->node_bootmem_map) return 0; map = bdata->node_bootmem_map; start = bdata->node_min_pfn; end = bdata->node_low_pfn; bdebug("nid=%td start=%lx end=%lx\n", bdata - bootmem_node_data, start, end); while (start < end) { unsigned long idx, vec; unsigned shift; idx = start - bdata->node_min_pfn; shift = idx & (BITS_PER_LONG - 1); /* * vec holds at most BITS_PER_LONG map bits, * bit 0 corresponds to start. */ vec = ~map[idx / BITS_PER_LONG]; if (shift) { vec >>= shift; if (end - start >= BITS_PER_LONG) vec |= ~map[idx / BITS_PER_LONG + 1] << (BITS_PER_LONG - shift); } /* * If we have a properly aligned and fully unreserved * BITS_PER_LONG block of pages in front of us, free * it in one go. */ if (IS_ALIGNED(start, BITS_PER_LONG) && vec == ~0UL) { int order = ilog2(BITS_PER_LONG); __free_pages_bootmem(pfn_to_page(start), start, order); count += BITS_PER_LONG; start += BITS_PER_LONG; } else { cur = start; start = ALIGN(start + 1, BITS_PER_LONG); while (vec && cur != start) { if (vec & 1) { page = pfn_to_page(cur); __free_pages_bootmem(page, cur, 0); count++; } vec >>= 1; ++cur; } } } cur = bdata->node_min_pfn; page = virt_to_page(bdata->node_bootmem_map); pages = bdata->node_low_pfn - bdata->node_min_pfn; pages = bootmem_bootmap_pages(pages); count += pages; while (pages--) __free_pages_bootmem(page++, cur++, 0); bdata->node_bootmem_map = NULL; bdebug("nid=%td released=%lx\n", bdata - bootmem_node_data, count); return count; } static int reset_managed_pages_done __initdata; void reset_node_managed_pages(pg_data_t *pgdat) { struct zone *z; for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++) z->managed_pages = 0; } void __init reset_all_zones_managed_pages(void) { struct pglist_data *pgdat; if (reset_managed_pages_done) return; for_each_online_pgdat(pgdat) reset_node_managed_pages(pgdat); reset_managed_pages_done = 1; } unsigned long __init free_all_bootmem(void) { unsigned long total_pages = 0; bootmem_data_t *bdata; reset_all_zones_managed_pages(); list_for_each_entry(bdata, &bdata_list, list) total_pages += free_all_bootmem_core(bdata); totalram_pages += total_pages; return total_pages; } static void __init __free(bootmem_data_t *bdata, unsigned long sidx, unsigned long eidx) { unsigned long idx; bdebug("nid=%td start=%lx end=%lx\n", bdata - bootmem_node_data, sidx + bdata->node_min_pfn, eidx + bdata->node_min_pfn); if (WARN_ON(bdata->node_bootmem_map == NULL)) return; if (bdata->hint_idx > sidx) bdata->hint_idx = sidx; for (idx = sidx; idx < eidx; idx++) if (!test_and_clear_bit(idx, bdata->node_bootmem_map)) BUG(); } static int __init __reserve(bootmem_data_t *bdata, unsigned long sidx, unsigned long eidx, int flags) { unsigned long idx; int exclusive = flags & BOOTMEM_EXCLUSIVE; bdebug("nid=%td start=%lx end=%lx flags=%x\n", bdata - bootmem_node_data, sidx + bdata->node_min_pfn, eidx + bdata->node_min_pfn, flags); if (WARN_ON(bdata->node_bootmem_map == NULL)) return 0; for (idx = sidx; idx < eidx; idx++) if (test_and_set_bit(idx, bdata->node_bootmem_map)) { if (exclusive) { __free(bdata, sidx, idx); return -EBUSY; } bdebug("silent double reserve of PFN %lx\n", idx + bdata->node_min_pfn); } return 0; } static int __init mark_bootmem_node(bootmem_data_t *bdata, unsigned long start, unsigned long end, int reserve, int flags) { unsigned long sidx, eidx; bdebug("nid=%td start=%lx end=%lx reserve=%d flags=%x\n", bdata - bootmem_node_data, start, end, reserve, flags); BUG_ON(start < bdata->node_min_pfn); BUG_ON(end > bdata->node_low_pfn); sidx = start - bdata->node_min_pfn; eidx = end - bdata->node_min_pfn; if (reserve) return __reserve(bdata, sidx, eidx, flags); else __free(bdata, sidx, eidx); return 0; } static int __init mark_bootmem(unsigned long start, unsigned long end, int reserve, int flags) { unsigned long pos; bootmem_data_t *bdata; pos = start; list_for_each_entry(bdata, &bdata_list, list) { int err; unsigned long max; if (pos < bdata->node_min_pfn || pos >= bdata->node_low_pfn) { BUG_ON(pos != start); continue; } max = min(bdata->node_low_pfn, end); err = mark_bootmem_node(bdata, pos, max, reserve, flags); if (reserve && err) { mark_bootmem(start, pos, 0, 0); return err; } if (max == end) return 0; pos = bdata->node_low_pfn; } BUG(); } void __init free_bootmem_node(pg_data_t *pgdat, unsigned long physaddr, unsigned long size) { unsigned long start, end; kmemleak_free_part_phys(physaddr, size); start = PFN_UP(physaddr); end = PFN_DOWN(physaddr + size); mark_bootmem_node(pgdat->bdata, start, end, 0, 0); } void __init free_bootmem(unsigned long physaddr, unsigned long size) { unsigned long start, end; kmemleak_free_part_phys(physaddr, size); start = PFN_UP(physaddr); end = PFN_DOWN(physaddr + size); mark_bootmem(start, end, 0, 0); } /** * reserve_bootmem_node - mark a page range as reserved * @pgdat: node the range resides on * @physaddr: starting address of the range * @size: size of the range in bytes * @flags: reservation flags (see linux/bootmem.h) * * Partial pages will be reserved. * * The range must reside completely on the specified node. * * Return: 0 on success, -errno on failure. */ int __init reserve_bootmem_node(pg_data_t *pgdat, unsigned long physaddr, unsigned long size, int flags) { unsigned long start, end; start = PFN_DOWN(physaddr); end = PFN_UP(physaddr + size); return mark_bootmem_node(pgdat->bdata, start, end, 1, flags); } /** * reserve_bootmem - mark a page range as reserved * @addr: starting address of the range * @size: size of the range in bytes * @flags: reservation flags (see linux/bootmem.h) * * Partial pages will be reserved. * * The range must be contiguous but may span node boundaries. * * Return: 0 on success, -errno on failure. */ int __init reserve_bootmem(unsigned long addr, unsigned long size, int flags) { unsigned long start, end; start = PFN_DOWN(addr); end = PFN_UP(addr + size); return mark_bootmem(start, end, 1, flags); } static unsigned long __init align_idx(struct bootmem_data *bdata, unsigned long idx, unsigned long step) { unsigned long base = bdata->node_min_pfn; /* * Align the index with respect to the node start so that the * combination of both satisfies the requested alignment. */ return ALIGN(base + idx, step) - base; } static unsigned long __init align_off(struct bootmem_data *bdata, unsigned long off, unsigned long align) { unsigned long base = PFN_PHYS(bdata->node_min_pfn); /* Same as align_idx for byte offsets */ return ALIGN(base + off, align) - base; } static void * __init alloc_bootmem_bdata(struct bootmem_data *bdata, unsigned long size, unsigned long align, unsigned long goal, unsigned long limit) { unsigned long fallback = 0; unsigned long min, max, start, sidx, midx, step; bdebug("nid=%td size=%lx [%lu pages] align=%lx goal=%lx limit=%lx\n", bdata - bootmem_node_data, size, PAGE_ALIGN(size) >> PAGE_SHIFT, align, goal, limit); BUG_ON(!size); BUG_ON(align & (align - 1)); BUG_ON(limit && goal + size > limit); if (!bdata->node_bootmem_map) return NULL; min = bdata->node_min_pfn; max = bdata->node_low_pfn; goal >>= PAGE_SHIFT; limit >>= PAGE_SHIFT; if (limit && max > limit) max = limit; if (max <= min) return NULL; step = max(align >> PAGE_SHIFT, 1UL); if (goal && min < goal && goal < max) start = ALIGN(goal, step); else start = ALIGN(min, step); sidx = start - bdata->node_min_pfn; midx = max - bdata->node_min_pfn; if (bdata->hint_idx > sidx) { /* * Handle the valid case of sidx being zero and still * catch the fallback below. */ fallback = sidx + 1; sidx = align_idx(bdata, bdata->hint_idx, step); } while (1) { int merge; void *region; unsigned long eidx, i, start_off, end_off; find_block: sidx = find_next_zero_bit(bdata->node_bootmem_map, midx, sidx); sidx = align_idx(bdata, sidx, step); eidx = sidx + PFN_UP(size); if (sidx >= midx || eidx > midx) break; for (i = sidx; i < eidx; i++) if (test_bit(i, bdata->node_bootmem_map)) { sidx = align_idx(bdata, i, step); if (sidx == i) sidx += step; goto find_block; } if (bdata->last_end_off & (PAGE_SIZE - 1) && PFN_DOWN(bdata->last_end_off) + 1 == sidx) start_off = align_off(bdata, bdata->last_end_off, align); else start_off = PFN_PHYS(sidx); merge = PFN_DOWN(start_off) < sidx; end_off = start_off + size; bdata->last_end_off = end_off; bdata->hint_idx = PFN_UP(end_off); /* * Reserve the area now: */ if (__reserve(bdata, PFN_DOWN(start_off) + merge, PFN_UP(end_off), BOOTMEM_EXCLUSIVE)) BUG(); region = phys_to_virt(PFN_PHYS(bdata->node_min_pfn) + start_off); memset(region, 0, size); /* * The min_count is set to 0 so that bootmem allocated blocks * are never reported as leaks. */ kmemleak_alloc(region, size, 0, 0); return region; } if (fallback) { sidx = align_idx(bdata, fallback - 1, step); fallback = 0; goto find_block; } return NULL; } static void * __init alloc_bootmem_core(unsigned long size, unsigned long align, unsigned long goal, unsigned long limit) { bootmem_data_t *bdata; void *region; if (WARN_ON_ONCE(slab_is_available())) return kzalloc(size, GFP_NOWAIT); list_for_each_entry(bdata, &bdata_list, list) { if (goal && bdata->node_low_pfn <= PFN_DOWN(goal)) continue; if (limit && bdata->node_min_pfn >= PFN_DOWN(limit)) break; region = alloc_bootmem_bdata(bdata, size, align, goal, limit); if (region) return region; } return NULL; } static void * __init ___alloc_bootmem_nopanic(unsigned long size, unsigned long align, unsigned long goal, unsigned long limit) { void *ptr; restart: ptr = alloc_bootmem_core(size, align, goal, limit); if (ptr) return ptr; if (goal) { goal = 0; goto restart; } return NULL; } void * __init __alloc_bootmem_nopanic(unsigned long size, unsigned long align, unsigned long goal) { unsigned long limit = 0; return ___alloc_bootmem_nopanic(size, align, goal, limit); } static void * __init ___alloc_bootmem(unsigned long size, unsigned long align, unsigned long goal, unsigned long limit) { void *mem = ___alloc_bootmem_nopanic(size, align, goal, limit); if (mem) return mem; /* * Whoops, we cannot satisfy the allocation request. */ pr_alert("bootmem alloc of %lu bytes failed!\n", size); panic("Out of memory"); return NULL; } void * __init __alloc_bootmem(unsigned long size, unsigned long align, unsigned long goal) { unsigned long limit = 0; return ___alloc_bootmem(size, align, goal, limit); } void * __init ___alloc_bootmem_node_nopanic(pg_data_t *pgdat, unsigned long size, unsigned long align, unsigned long goal, unsigned long limit) { void *ptr; if (WARN_ON_ONCE(slab_is_available())) return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id); again: /* do not panic in alloc_bootmem_bdata() */ if (limit && goal + size > limit) limit = 0; ptr = alloc_bootmem_bdata(pgdat->bdata, size, align, goal, limit); if (ptr) return ptr; ptr = alloc_bootmem_core(size, align, goal, limit); if (ptr) return ptr; if (goal) { goal = 0; goto again; } return NULL; } void * __init __alloc_bootmem_node_nopanic(pg_data_t *pgdat, unsigned long size, unsigned long align, unsigned long goal) { return ___alloc_bootmem_node_nopanic(pgdat, size, align, goal, 0); } void * __init ___alloc_bootmem_node(pg_data_t *pgdat, unsigned long size, unsigned long align, unsigned long goal, unsigned long limit) { void *ptr; ptr = ___alloc_bootmem_node_nopanic(pgdat, size, align, goal, 0); if (ptr) return ptr; pr_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) { if (WARN_ON_ONCE(slab_is_available())) return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id); return ___alloc_bootmem_node(pgdat, size, align, goal, 0); } void * __init __alloc_bootmem_node_high(pg_data_t *pgdat, unsigned long size, unsigned long align, unsigned long goal) { #ifdef MAX_DMA32_PFN unsigned long end_pfn; if (WARN_ON_ONCE(slab_is_available())) return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id); /* update goal according ...MAX_DMA32_PFN */ end_pfn = pgdat_end_pfn(pgdat); if (end_pfn > MAX_DMA32_PFN + (128 >> (20 - PAGE_SHIFT)) && (goal >> PAGE_SHIFT) < MAX_DMA32_PFN) { void *ptr; unsigned long new_goal; new_goal = MAX_DMA32_PFN << PAGE_SHIFT; ptr = alloc_bootmem_bdata(pgdat->bdata, size, align, new_goal, 0); if (ptr) return ptr; } #endif return __alloc_bootmem_node(pgdat, size, align, goal); } void * __init __alloc_bootmem_low(unsigned long size, unsigned long align, unsigned long goal) { return ___alloc_bootmem(size, align, goal, ARCH_LOW_ADDRESS_LIMIT); } void * __init __alloc_bootmem_low_nopanic(unsigned long size, unsigned long align, unsigned long goal) { return ___alloc_bootmem_nopanic(size, align, goal, ARCH_LOW_ADDRESS_LIMIT); } void * __init __alloc_bootmem_low_node(pg_data_t *pgdat, unsigned long size, unsigned long align, unsigned long goal) { if (WARN_ON_ONCE(slab_is_available())) return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id); return ___alloc_bootmem_node(pgdat, size, align, goal, ARCH_LOW_ADDRESS_LIMIT); }