kernel-hacking-2024-linux-steffo/arch/x86/mm/discontig_32.c

/*
 * Written by: Patricia Gaughen <gone@us.ibm.com>, IBM Corporation
 * August 2002: added remote node KVA remap - Martin J. Bligh 
 *
 * Copyright (C) 2002, IBM Corp.
 *
 * All rights reserved.          
 *
 * 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, GOOD TITLE or
 * NON INFRINGEMENT.  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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/mm.h>
#include <linux/bootmem.h>
#include <linux/mmzone.h>
#include <linux/highmem.h>
#include <linux/initrd.h>
#include <linux/nodemask.h>
#include <linux/module.h>
#include <linux/kexec.h>
#include <linux/pfn.h>
#include <linux/swap.h>
#include <linux/acpi.h>

#include <asm/e820.h>
#include <asm/setup.h>
#include <asm/mmzone.h>
#include <asm/bios_ebda.h>

struct pglist_data *node_data[MAX_NUMNODES] __read_mostly;
EXPORT_SYMBOL(node_data);
static bootmem_data_t node0_bdata;

/*
 * numa interface - we expect the numa architecture specific code to have
 *                  populated the following initialisation.
 *
 * 1) node_online_map  - the map of all nodes configured (online) in the system
 * 2) node_start_pfn   - the starting page frame number for a node
 * 3) node_end_pfn     - the ending page fram number for a node
 */
unsigned long node_start_pfn[MAX_NUMNODES] __read_mostly;
unsigned long node_end_pfn[MAX_NUMNODES] __read_mostly;


#ifdef CONFIG_DISCONTIGMEM
/*
 * 4) physnode_map     - the mapping between a pfn and owning node
 * physnode_map keeps track of the physical memory layout of a generic
 * numa node on a 256Mb break (each element of the array will
 * represent 256Mb of memory and will be marked by the node id.  so,
 * if the first gig is on node 0, and the second gig is on node 1
 * physnode_map will contain:
 *
 *     physnode_map[0-3] = 0;
 *     physnode_map[4-7] = 1;
 *     physnode_map[8- ] = -1;
 */
s8 physnode_map[MAX_ELEMENTS] __read_mostly = { [0 ... (MAX_ELEMENTS - 1)] = -1};
EXPORT_SYMBOL(physnode_map);

void memory_present(int nid, unsigned long start, unsigned long end)
{
	unsigned long pfn;

	printk(KERN_INFO "Node: %d, start_pfn: %ld, end_pfn: %ld\n",
			nid, start, end);
	printk(KERN_DEBUG "  Setting physnode_map array to node %d for pfns:\n", nid);
	printk(KERN_DEBUG "  ");
	for (pfn = start; pfn < end; pfn += PAGES_PER_ELEMENT) {
		physnode_map[pfn / PAGES_PER_ELEMENT] = nid;
		printk("%ld ", pfn);
	}
	printk("\n");
}

unsigned long node_memmap_size_bytes(int nid, unsigned long start_pfn,
					      unsigned long end_pfn)
{
	unsigned long nr_pages = end_pfn - start_pfn;

	if (!nr_pages)
		return 0;

	return (nr_pages + 1) * sizeof(struct page);
}
#endif

extern unsigned long find_max_low_pfn(void);
extern void add_one_highpage_init(struct page *, int, int);
extern unsigned long highend_pfn, highstart_pfn;

#define LARGE_PAGE_BYTES (PTRS_PER_PTE * PAGE_SIZE)

unsigned long node_remap_size[MAX_NUMNODES];
static void *node_remap_start_vaddr[MAX_NUMNODES];
void set_pmd_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags);

static unsigned long kva_start_pfn;
static unsigned long kva_pages;
/*
 * FLAT - support for basic PC memory model with discontig enabled, essentially
 *        a single node with all available processors in it with a flat
 *        memory map.
 */
int __init get_memcfg_numa_flat(void)
{
	printk("NUMA - single node, flat memory mode\n");

	/* Run the memory configuration and find the top of memory. */
	propagate_e820_map();
	node_start_pfn[0] = 0;
	node_end_pfn[0] = max_pfn;
	memory_present(0, 0, max_pfn);

        /* Indicate there is one node available. */
	nodes_clear(node_online_map);
	node_set_online(0);
	return 1;
}

/*
 * Find the highest page frame number we have available for the node
 */
static void __init propagate_e820_map_node(int nid)
{
	if (node_end_pfn[nid] > max_pfn)
		node_end_pfn[nid] = max_pfn;
	/*
	 * if a user has given mem=XXXX, then we need to make sure 
	 * that the node _starts_ before that, too, not just ends
	 */
	if (node_start_pfn[nid] > max_pfn)
		node_start_pfn[nid] = max_pfn;
	BUG_ON(node_start_pfn[nid] > node_end_pfn[nid]);
}

/* 
 * Allocate memory for the pg_data_t for this node via a crude pre-bootmem
 * method.  For node zero take this from the bottom of memory, for
 * subsequent nodes place them at node_remap_start_vaddr which contains
 * node local data in physically node local memory.  See setup_memory()
 * for details.
 */
static void __init allocate_pgdat(int nid)
{
	if (nid && node_has_online_mem(nid))
		NODE_DATA(nid) = (pg_data_t *)node_remap_start_vaddr[nid];
	else {
		NODE_DATA(nid) = (pg_data_t *)(pfn_to_kaddr(min_low_pfn));
		min_low_pfn += PFN_UP(sizeof(pg_data_t));
	}
}

/*
 * In the DISCONTIGMEM and SPARSEMEM memory model, a portion of the kernel
 * virtual address space (KVA) is reserved and portions of nodes are mapped
 * using it. This is to allow node-local memory to be allocated for
 * structures that would normally require ZONE_NORMAL. The memory is
 * allocated with alloc_remap() and callers should be prepared to allocate
 * from the bootmem allocator instead.
 */
static unsigned long node_remap_start_pfn[MAX_NUMNODES];
static void *node_remap_end_vaddr[MAX_NUMNODES];
static void *node_remap_alloc_vaddr[MAX_NUMNODES];
static unsigned long node_remap_offset[MAX_NUMNODES];

void *alloc_remap(int nid, unsigned long size)
{
	void *allocation = node_remap_alloc_vaddr[nid];

	size = ALIGN(size, L1_CACHE_BYTES);

	if (!allocation || (allocation + size) >= node_remap_end_vaddr[nid])
		return 0;

	node_remap_alloc_vaddr[nid] += size;
	memset(allocation, 0, size);

	return allocation;
}

void __init remap_numa_kva(void)
{
	void *vaddr;
	unsigned long pfn;
	int node;

	for_each_online_node(node) {
		for (pfn=0; pfn < node_remap_size[node]; pfn += PTRS_PER_PTE) {
			vaddr = node_remap_start_vaddr[node]+(pfn<<PAGE_SHIFT);
			set_pmd_pfn((ulong) vaddr, 
				node_remap_start_pfn[node] + pfn, 
				PAGE_KERNEL_LARGE);
		}
	}
}

static unsigned long calculate_numa_remap_pages(void)
{
	int nid;
	unsigned long size, reserve_pages = 0;
	unsigned long pfn;

	for_each_online_node(nid) {
		unsigned old_end_pfn = node_end_pfn[nid];

		/*
		 * The acpi/srat node info can show hot-add memroy zones
		 * where memory could be added but not currently present.
		 */
		if (node_start_pfn[nid] > max_pfn)
			continue;
		if (node_end_pfn[nid] > max_pfn)
			node_end_pfn[nid] = max_pfn;

		/* ensure the remap includes space for the pgdat. */
		size = node_remap_size[nid] + sizeof(pg_data_t);

		/* convert size to large (pmd size) pages, rounding up */
		size = (size + LARGE_PAGE_BYTES - 1) / LARGE_PAGE_BYTES;
		/* now the roundup is correct, convert to PAGE_SIZE pages */
		size = size * PTRS_PER_PTE;

		/*
		 * Validate the region we are allocating only contains valid
		 * pages.
		 */
		for (pfn = node_end_pfn[nid] - size;
		     pfn < node_end_pfn[nid]; pfn++)
			if (!page_is_ram(pfn))
				break;

		if (pfn != node_end_pfn[nid])
			size = 0;

		printk("Reserving %ld pages of KVA for lmem_map of node %d\n",
				size, nid);
		node_remap_size[nid] = size;
		node_remap_offset[nid] = reserve_pages;
		reserve_pages += size;
		printk("Shrinking node %d from %ld pages to %ld pages\n",
			nid, node_end_pfn[nid], node_end_pfn[nid] - size);

		if (node_end_pfn[nid] & (PTRS_PER_PTE-1)) {
			/*
			 * Align node_end_pfn[] and node_remap_start_pfn[] to
			 * pmd boundary. remap_numa_kva will barf otherwise.
			 */
			printk("Shrinking node %d further by %ld pages for proper alignment\n",
				nid, node_end_pfn[nid] & (PTRS_PER_PTE-1));
			size +=  node_end_pfn[nid] & (PTRS_PER_PTE-1);
		}

		node_end_pfn[nid] -= size;
		node_remap_start_pfn[nid] = node_end_pfn[nid];
		shrink_active_range(nid, old_end_pfn, node_end_pfn[nid]);
	}
	printk("Reserving total of %ld pages for numa KVA remap\n",
			reserve_pages);
	return reserve_pages;
}

static void init_remap_allocator(int nid)
{
	node_remap_start_vaddr[nid] = pfn_to_kaddr(
			kva_start_pfn + node_remap_offset[nid]);
	node_remap_end_vaddr[nid] = node_remap_start_vaddr[nid] +
		(node_remap_size[nid] * PAGE_SIZE);
	node_remap_alloc_vaddr[nid] = node_remap_start_vaddr[nid] +
		ALIGN(sizeof(pg_data_t), PAGE_SIZE);

	printk ("node %d will remap to vaddr %08lx - %08lx\n", nid,
		(ulong) node_remap_start_vaddr[nid],
		(ulong) pfn_to_kaddr(highstart_pfn
		   + node_remap_offset[nid] + node_remap_size[nid]));
}

extern void setup_bootmem_allocator(void);
unsigned long __init setup_memory(void)
{
	int nid;
	unsigned long system_start_pfn, system_max_low_pfn;
	unsigned long wasted_pages;

	/*
	 * When mapping a NUMA machine we allocate the node_mem_map arrays
	 * from node local memory.  They are then mapped directly into KVA
	 * between zone normal and vmalloc space.  Calculate the size of
	 * this space and use it to adjust the boundary between ZONE_NORMAL
	 * and ZONE_HIGHMEM.
	 */
	get_memcfg_numa();

	kva_pages = calculate_numa_remap_pages();

	/* partially used pages are not usable - thus round upwards */
	system_start_pfn = min_low_pfn = PFN_UP(init_pg_tables_end);

	kva_start_pfn = find_max_low_pfn() - kva_pages;

#ifdef CONFIG_BLK_DEV_INITRD
	/* Numa kva area is below the initrd */
	if (initrd_start)
		kva_start_pfn = PFN_DOWN(initrd_start - PAGE_OFFSET)
			- kva_pages;
#endif

	/*
	 * We waste pages past at the end of the KVA for no good reason other
	 * than how it is located. This is bad.
	 */
	wasted_pages = kva_start_pfn & (PTRS_PER_PTE-1);
	kva_start_pfn -= wasted_pages;
	kva_pages += wasted_pages;

	system_max_low_pfn = max_low_pfn = find_max_low_pfn();
	printk("kva_start_pfn ~ %ld find_max_low_pfn() ~ %ld\n",
		kva_start_pfn, max_low_pfn);
	printk("max_pfn = %ld\n", max_pfn);
#ifdef CONFIG_HIGHMEM
	highstart_pfn = highend_pfn = max_pfn;
	if (max_pfn > system_max_low_pfn)
		highstart_pfn = system_max_low_pfn;
	printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
	       pages_to_mb(highend_pfn - highstart_pfn));
	num_physpages = highend_pfn;
	high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
#else
	num_physpages = system_max_low_pfn;
	high_memory = (void *) __va(system_max_low_pfn * PAGE_SIZE - 1) + 1;
#endif
	printk(KERN_NOTICE "%ldMB LOWMEM available.\n",
			pages_to_mb(system_max_low_pfn));
	printk("min_low_pfn = %ld, max_low_pfn = %ld, highstart_pfn = %ld\n", 
			min_low_pfn, max_low_pfn, highstart_pfn);

	printk("Low memory ends at vaddr %08lx\n",
			(ulong) pfn_to_kaddr(max_low_pfn));
	for_each_online_node(nid) {
		init_remap_allocator(nid);

		allocate_pgdat(nid);
	}
	printk("High memory starts at vaddr %08lx\n",
			(ulong) pfn_to_kaddr(highstart_pfn));
	for_each_online_node(nid)
		propagate_e820_map_node(nid);

	memset(NODE_DATA(0), 0, sizeof(struct pglist_data));
	NODE_DATA(0)->bdata = &node0_bdata;
	setup_bootmem_allocator();
	return max_low_pfn;
}

void __init numa_kva_reserve(void)
{
	if (kva_pages)
		reserve_bootmem(PFN_PHYS(kva_start_pfn), PFN_PHYS(kva_pages),
				BOOTMEM_DEFAULT);
}

void __init zone_sizes_init(void)
{
	int nid;
	unsigned long max_zone_pfns[MAX_NR_ZONES];
	memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
	max_zone_pfns[ZONE_DMA] =
		virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
	max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
#ifdef CONFIG_HIGHMEM
	max_zone_pfns[ZONE_HIGHMEM] = highend_pfn;
#endif

	/* If SRAT has not registered memory, register it now */
	if (find_max_pfn_with_active_regions() == 0) {
		for_each_online_node(nid) {
			if (node_has_online_mem(nid))
				add_active_range(nid, node_start_pfn[nid],
							node_end_pfn[nid]);
		}
	}

	free_area_init_nodes(max_zone_pfns);
	return;
}

void __init set_highmem_pages_init(int bad_ppro) 
{
#ifdef CONFIG_HIGHMEM
	struct zone *zone;
	struct page *page;

	for_each_zone(zone) {
		unsigned long node_pfn, zone_start_pfn, zone_end_pfn;

		if (!is_highmem(zone))
			continue;

		zone_start_pfn = zone->zone_start_pfn;
		zone_end_pfn = zone_start_pfn + zone->spanned_pages;

		printk("Initializing %s for node %d (%08lx:%08lx)\n",
				zone->name, zone_to_nid(zone),
				zone_start_pfn, zone_end_pfn);

		for (node_pfn = zone_start_pfn; node_pfn < zone_end_pfn; node_pfn++) {
			if (!pfn_valid(node_pfn))
				continue;
			page = pfn_to_page(node_pfn);
			add_one_highpage_init(page, node_pfn, bad_ppro);
		}
	}
	totalram_pages += totalhigh_pages;
#endif
}

#ifdef CONFIG_MEMORY_HOTPLUG
static int paddr_to_nid(u64 addr)
{
	int nid;
	unsigned long pfn = PFN_DOWN(addr);

	for_each_node(nid)
		if (node_start_pfn[nid] <= pfn &&
		    pfn < node_end_pfn[nid])
			return nid;

	return -1;
}

/*
 * This function is used to ask node id BEFORE memmap and mem_section's
 * initialization (pfn_to_nid() can't be used yet).
 * If _PXM is not defined on ACPI's DSDT, node id must be found by this.
 */
int memory_add_physaddr_to_nid(u64 addr)
{
	int nid = paddr_to_nid(addr);
	return (nid >= 0) ? nid : 0;
}

EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid);
#endif