source: trunk/packages/xen-3.1/xen-3.1/linux-2.6-xen-sparse/arch/x86_64/kernel/e820-xen.c @ 34

/* 
 * Handle the memory map.
 * The functions here do the job until bootmem takes over.
 *
 *  Getting sanitize_e820_map() in sync with i386 version by applying change:
 *  -  Provisions for empty E820 memory regions (reported by certain BIOSes).
 *     Alex Achenbach <xela@slit.de>, December 2002.
 *  Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
 *
 */
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/ioport.h>
#include <linux/string.h>
#include <linux/kexec.h>
#include <linux/module.h>

#include <asm/pgtable.h>
#include <asm/page.h>
#include <asm/e820.h>
#include <asm/proto.h>
#include <asm/bootsetup.h>
#include <asm/sections.h>
#include <xen/interface/memory.h>

/* 
 * PFN of last memory page.
 */
unsigned long end_pfn; 
EXPORT_SYMBOL(end_pfn);

/* 
 * end_pfn only includes RAM, while end_pfn_map includes all e820 entries.
 * The direct mapping extends to end_pfn_map, so that we can directly access
 * apertures, ACPI and other tables without having to play with fixmaps.
 */ 
unsigned long end_pfn_map; 

/* 
 * Last pfn which the user wants to use.
 */
unsigned long end_user_pfn = MAXMEM>>PAGE_SHIFT;  

extern struct resource code_resource, data_resource;

/* Check for some hardcoded bad areas that early boot is not allowed to touch */ 
static inline int bad_addr(unsigned long *addrp, unsigned long size)
{ 
        unsigned long addr = *addrp, last = addr + size; 

#ifndef CONFIG_XEN
        /* various gunk below that needed for SMP startup */
        if (addr < 0x8000) { 
                *addrp = 0x8000;
                return 1; 
        }

        /* direct mapping tables of the kernel */
        if (last >= table_start<<PAGE_SHIFT && addr < table_end<<PAGE_SHIFT) { 
                *addrp = table_end << PAGE_SHIFT; 
                return 1;
        } 

        /* initrd */ 
#ifdef CONFIG_BLK_DEV_INITRD
        if (LOADER_TYPE && INITRD_START && last >= INITRD_START && 
            addr < INITRD_START+INITRD_SIZE) { 
                *addrp = INITRD_START + INITRD_SIZE; 
                return 1;
        } 
#endif
        /* kernel code + 640k memory hole (later should not be needed, but 
           be paranoid for now) */
        if (last >= 640*1024 && addr < 1024*1024) {
                *addrp = 1024*1024;
                return 1;
        }
        if (last >= __pa_symbol(&_text) && last < __pa_symbol(&_end)) {
                *addrp = __pa_symbol(&_end);
                return 1;
        }

        if (last >= ebda_addr && addr < ebda_addr + ebda_size) {
                *addrp = ebda_addr + ebda_size;
                return 1;
        }

        /* XXX ramdisk image here? */ 
#else
        if (last < (table_end<<PAGE_SHIFT)) {
                *addrp = table_end << PAGE_SHIFT;
                return 1;
        }
#endif
        return 0;
} 

#ifndef CONFIG_XEN
/*
 * This function checks if any part of the range <start,end> is mapped
 * with type.
 */
int __meminit
e820_any_mapped(unsigned long start, unsigned long end, unsigned type)
{ 
        int i;
        for (i = 0; i < e820.nr_map; i++) { 
                struct e820entry *ei = &e820.map[i]; 
                if (type && ei->type != type) 
                        continue;
                if (ei->addr >= end || ei->addr + ei->size <= start)
                        continue; 
                return 1; 
        } 
        return 0;
}
#endif

/*
 * This function checks if the entire range <start,end> is mapped with type.
 *
 * Note: this function only works correct if the e820 table is sorted and
 * not-overlapping, which is the case
 */
int __init e820_all_mapped(unsigned long start, unsigned long end, unsigned type)
{
        int i;

#ifndef CONFIG_XEN
        for (i = 0; i < e820.nr_map; i++) {
                struct e820entry *ei = &e820.map[i];
#else
        extern struct e820map machine_e820;

        if (!is_initial_xendomain())
                return 0;
        for (i = 0; i < machine_e820.nr_map; i++) {
                const struct e820entry *ei = &machine_e820.map[i];
#endif

                if (type && ei->type != type)
                        continue;
                /* is the region (part) in overlap with the current region ?*/
                if (ei->addr >= end || ei->addr + ei->size <= start)
                        continue;

                /* if the region is at the beginning of <start,end> we move
                 * start to the end of the region since it's ok until there
                 */
                if (ei->addr <= start)
                        start = ei->addr + ei->size;
                /* if start is now at or beyond end, we're done, full coverage */
                if (start >= end)
                        return 1; /* we're done */
        }
        return 0;
}

/* 
 * Find a free area in a specific range. 
 */ 
unsigned long __init find_e820_area(unsigned long start, unsigned long end, unsigned size) 
{ 
        int i; 
        for (i = 0; i < e820.nr_map; i++) { 
                struct e820entry *ei = &e820.map[i]; 
                unsigned long addr = ei->addr, last; 
                if (ei->type != E820_RAM) 
                        continue; 
                if (addr < start) 
                        addr = start;
                if (addr > ei->addr + ei->size) 
                        continue; 
                while (bad_addr(&addr, size) && addr+size <= ei->addr+ei->size)
                        ;
                last = addr + size;
                if (last > ei->addr + ei->size)
                        continue;
                if (last > end) 
                        continue;
                return addr; 
        } 
        return -1UL;            
} 

/* 
 * Free bootmem based on the e820 table for a node.
 */
void __init e820_bootmem_free(pg_data_t *pgdat, unsigned long start,unsigned long end)
{
        int i;
        for (i = 0; i < e820.nr_map; i++) {
                struct e820entry *ei = &e820.map[i]; 
                unsigned long last, addr;

                if (ei->type != E820_RAM || 
                    ei->addr+ei->size <= start || 
                    ei->addr >= end)
                        continue;

                addr = round_up(ei->addr, PAGE_SIZE);
                if (addr < start) 
                        addr = start;

                last = round_down(ei->addr + ei->size, PAGE_SIZE); 
                if (last >= end)
                        last = end; 

                if (last > addr && last-addr >= PAGE_SIZE)
                        free_bootmem_node(pgdat, addr, last-addr);
        }
}

/*
 * Find the highest page frame number we have available
 */
unsigned long __init e820_end_of_ram(void)
{
        int i;
        unsigned long end_pfn = 0;
        
        for (i = 0; i < e820.nr_map; i++) {
                struct e820entry *ei = &e820.map[i]; 
                unsigned long start, end;

                start = round_up(ei->addr, PAGE_SIZE); 
                end = round_down(ei->addr + ei->size, PAGE_SIZE); 
                if (start >= end)
                        continue;
                if (ei->type == E820_RAM) { 
                if (end > end_pfn<<PAGE_SHIFT)
                        end_pfn = end>>PAGE_SHIFT;
                } else { 
                        if (end > end_pfn_map<<PAGE_SHIFT) 
                                end_pfn_map = end>>PAGE_SHIFT;
                } 
        }

        if (end_pfn > end_pfn_map) 
                end_pfn_map = end_pfn;
        if (end_pfn_map > MAXMEM>>PAGE_SHIFT)
                end_pfn_map = MAXMEM>>PAGE_SHIFT;
        if (end_pfn > end_user_pfn)
                end_pfn = end_user_pfn;
        if (end_pfn > end_pfn_map) 
                end_pfn = end_pfn_map; 

        return end_pfn; 
}

/* 
 * Compute how much memory is missing in a range.
 * Unlike the other functions in this file the arguments are in page numbers.
 */
unsigned long __init
e820_hole_size(unsigned long start_pfn, unsigned long end_pfn)
{
        unsigned long ram = 0;
        unsigned long start = start_pfn << PAGE_SHIFT;
        unsigned long end = end_pfn << PAGE_SHIFT;
        int i;
        for (i = 0; i < e820.nr_map; i++) {
                struct e820entry *ei = &e820.map[i];
                unsigned long last, addr;

                if (ei->type != E820_RAM ||
                    ei->addr+ei->size <= start ||
                    ei->addr >= end)
                        continue;

                addr = round_up(ei->addr, PAGE_SIZE);
                if (addr < start)
                        addr = start;

                last = round_down(ei->addr + ei->size, PAGE_SIZE);
                if (last >= end)
                        last = end;

                if (last > addr)
                        ram += last - addr;
        }
        return ((end - start) - ram) >> PAGE_SHIFT;
}

/*
 * Mark e820 reserved areas as busy for the resource manager.
 */
void __init e820_reserve_resources(struct e820entry *e820, int nr_map)
{
        int i;
        for (i = 0; i < nr_map; i++) {
                struct resource *res;
                res = alloc_bootmem_low(sizeof(struct resource));
                switch (e820[i].type) {
                case E820_RAM:  res->name = "System RAM"; break;
                case E820_ACPI: res->name = "ACPI Tables"; break;
                case E820_NVS:  res->name = "ACPI Non-volatile Storage"; break;
                default:        res->name = "reserved";
                }
                res->start = e820[i].addr;
                res->end = res->start + e820[i].size - 1;
                res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
                request_resource(&iomem_resource, res);
                if (e820[i].type == E820_RAM) {
                        /*
                         *  We don't know which RAM region contains kernel data,
                         *  so we try it repeatedly and let the resource manager
                         *  test it.
                         */
#ifndef CONFIG_XEN
                        request_resource(res, &code_resource);
                        request_resource(res, &data_resource);
#endif
#ifdef CONFIG_KEXEC
                        if (crashk_res.start != crashk_res.end)
                                request_resource(res, &crashk_res);
#ifdef CONFIG_XEN
                        xen_machine_kexec_register_resources(res);
#endif
#endif
                }
        }
}

/* 
 * Add a memory region to the kernel e820 map.
 */ 
void __init add_memory_region(unsigned long start, unsigned long size, int type)
{
        int x = e820.nr_map;

        if (x == E820MAX) {
                printk(KERN_ERR "Ooops! Too many entries in the memory map!\n");
                return;
        }

        e820.map[x].addr = start;
        e820.map[x].size = size;
        e820.map[x].type = type;
        e820.nr_map++;
}

void __init e820_print_map(char *who)
{
        int i;

        for (i = 0; i < e820.nr_map; i++) {
                printk(" %s: %016Lx - %016Lx ", who,
                        (unsigned long long) e820.map[i].addr,
                        (unsigned long long) (e820.map[i].addr + e820.map[i].size));
                switch (e820.map[i].type) {
                case E820_RAM:  printk("(usable)\n");
                                break;
                case E820_RESERVED:
                                printk("(reserved)\n");
                                break;
                case E820_ACPI:
                                printk("(ACPI data)\n");
                                break;
                case E820_NVS:
                                printk("(ACPI NVS)\n");
                                break;
                default:        printk("type %u\n", e820.map[i].type);
                                break;
                }
        }
}

/*
 * Sanitize the BIOS e820 map.
 *
 * Some e820 responses include overlapping entries.  The following 
 * replaces the original e820 map with a new one, removing overlaps.
 *
 */
static int __init sanitize_e820_map(struct e820entry * biosmap, char * pnr_map)
{
        struct change_member {
                struct e820entry *pbios; /* pointer to original bios entry */
                unsigned long long addr; /* address for this change point */
        };
        static struct change_member change_point_list[2*E820MAX] __initdata;
        static struct change_member *change_point[2*E820MAX] __initdata;
        static struct e820entry *overlap_list[E820MAX] __initdata;
        static struct e820entry new_bios[E820MAX] __initdata;
        struct change_member *change_tmp;
        unsigned long current_type, last_type;
        unsigned long long last_addr;
        int chgidx, still_changing;
        int overlap_entries;
        int new_bios_entry;
        int old_nr, new_nr, chg_nr;
        int i;

        /*
                Visually we're performing the following (1,2,3,4 = memory types)...

                Sample memory map (w/overlaps):
                   ____22__________________
                   ______________________4_
                   ____1111________________
                   _44_____________________
                   11111111________________
                   ____________________33__
                   ___________44___________
                   __________33333_________
                   ______________22________
                   ___________________2222_
                   _________111111111______
                   _____________________11_
                   _________________4______

                Sanitized equivalent (no overlap):
                   1_______________________
                   _44_____________________
                   ___1____________________
                   ____22__________________
                   ______11________________
                   _________1______________
                   __________3_____________
                   ___________44___________
                   _____________33_________
                   _______________2________
                   ________________1_______
                   _________________4______
                   ___________________2____
                   ____________________33__
                   ______________________4_
        */

        /* if there's only one memory region, don't bother */
        if (*pnr_map < 2)
                return -1;

        old_nr = *pnr_map;

        /* bail out if we find any unreasonable addresses in bios map */
        for (i=0; i<old_nr; i++)
                if (biosmap[i].addr + biosmap[i].size < biosmap[i].addr)
                        return -1;

        /* create pointers for initial change-point information (for sorting) */
        for (i=0; i < 2*old_nr; i++)
                change_point[i] = &change_point_list[i];

        /* record all known change-points (starting and ending addresses),
           omitting those that are for empty memory regions */
        chgidx = 0;
        for (i=0; i < old_nr; i++)      {
                if (biosmap[i].size != 0) {
                        change_point[chgidx]->addr = biosmap[i].addr;
                        change_point[chgidx++]->pbios = &biosmap[i];
                        change_point[chgidx]->addr = biosmap[i].addr + biosmap[i].size;
                        change_point[chgidx++]->pbios = &biosmap[i];
                }
        }
        chg_nr = chgidx;

        /* sort change-point list by memory addresses (low -> high) */
        still_changing = 1;
        while (still_changing)  {
                still_changing = 0;
                for (i=1; i < chg_nr; i++)  {
                        /* if <current_addr> > <last_addr>, swap */
                        /* or, if current=<start_addr> & last=<end_addr>, swap */
                        if ((change_point[i]->addr < change_point[i-1]->addr) ||
                                ((change_point[i]->addr == change_point[i-1]->addr) &&
                                 (change_point[i]->addr == change_point[i]->pbios->addr) &&
                                 (change_point[i-1]->addr != change_point[i-1]->pbios->addr))
                           )
                        {
                                change_tmp = change_point[i];
                                change_point[i] = change_point[i-1];
                                change_point[i-1] = change_tmp;
                                still_changing=1;
                        }
                }
        }

        /* create a new bios memory map, removing overlaps */
        overlap_entries=0;       /* number of entries in the overlap table */
        new_bios_entry=0;        /* index for creating new bios map entries */
        last_type = 0;           /* start with undefined memory type */
        last_addr = 0;           /* start with 0 as last starting address */
        /* loop through change-points, determining affect on the new bios map */
        for (chgidx=0; chgidx < chg_nr; chgidx++)
        {
                /* keep track of all overlapping bios entries */
                if (change_point[chgidx]->addr == change_point[chgidx]->pbios->addr)
                {
                        /* add map entry to overlap list (> 1 entry implies an overlap) */
                        overlap_list[overlap_entries++]=change_point[chgidx]->pbios;
                }
                else
                {
                        /* remove entry from list (order independent, so swap with last) */
                        for (i=0; i<overlap_entries; i++)
                        {
                                if (overlap_list[i] == change_point[chgidx]->pbios)
                                        overlap_list[i] = overlap_list[overlap_entries-1];
                        }
                        overlap_entries--;
                }
                /* if there are overlapping entries, decide which "type" to use */
                /* (larger value takes precedence -- 1=usable, 2,3,4,4+=unusable) */
                current_type = 0;
                for (i=0; i<overlap_entries; i++)
                        if (overlap_list[i]->type > current_type)
                                current_type = overlap_list[i]->type;
                /* continue building up new bios map based on this information */
                if (current_type != last_type)  {
                        if (last_type != 0)      {
                                new_bios[new_bios_entry].size =
                                        change_point[chgidx]->addr - last_addr;
                                /* move forward only if the new size was non-zero */
                                if (new_bios[new_bios_entry].size != 0)
                                        if (++new_bios_entry >= E820MAX)
                                                break;  /* no more space left for new bios entries */
                        }
                        if (current_type != 0)  {
                                new_bios[new_bios_entry].addr = change_point[chgidx]->addr;
                                new_bios[new_bios_entry].type = current_type;
                                last_addr=change_point[chgidx]->addr;
                        }
                        last_type = current_type;
                }
        }
        new_nr = new_bios_entry;   /* retain count for new bios entries */

        /* copy new bios mapping into original location */
        memcpy(biosmap, new_bios, new_nr*sizeof(struct e820entry));
        *pnr_map = new_nr;

        return 0;
}

/*
 * Copy the BIOS e820 map into a safe place.
 *
 * Sanity-check it while we're at it..
 *
 * If we're lucky and live on a modern system, the setup code
 * will have given us a memory map that we can use to properly
 * set up memory.  If we aren't, we'll fake a memory map.
 *
 * We check to see that the memory map contains at least 2 elements
 * before we'll use it, because the detection code in setup.S may
 * not be perfect and most every PC known to man has two memory
 * regions: one from 0 to 640k, and one from 1mb up.  (The IBM
 * thinkpad 560x, for example, does not cooperate with the memory
 * detection code.)
 */
static int __init copy_e820_map(struct e820entry * biosmap, int nr_map)
{
#ifndef CONFIG_XEN
        /* Only one memory region (or negative)? Ignore it */
        if (nr_map < 2)
                return -1;
#else
        BUG_ON(nr_map < 1);
#endif

        do {
                unsigned long start = biosmap->addr;
                unsigned long size = biosmap->size;
                unsigned long end = start + size;
                unsigned long type = biosmap->type;

                /* Overflow in 64 bits? Ignore the memory map. */
                if (start > end)
                        return -1;

#ifndef CONFIG_XEN
                /*
                 * Some BIOSes claim RAM in the 640k - 1M region.
                 * Not right. Fix it up.
                 * 
                 * This should be removed on Hammer which is supposed to not
                 * have non e820 covered ISA mappings there, but I had some strange
                 * problems so it stays for now.  -AK
                 */
                if (type == E820_RAM) {
                        if (start < 0x100000ULL && end > 0xA0000ULL) {
                                if (start < 0xA0000ULL)
                                        add_memory_region(start, 0xA0000ULL-start, type);
                                if (end <= 0x100000ULL)
                                        continue;
                                start = 0x100000ULL;
                                size = end - start;
                        }
                }
#endif

                add_memory_region(start, size, type);
        } while (biosmap++,--nr_map);
        return 0;
}

#ifndef CONFIG_XEN
void __init setup_memory_region(void)
{
        char *who = "BIOS-e820";

        /*
         * Try to copy the BIOS-supplied E820-map.
         *
         * Otherwise fake a memory map; one section from 0k->640k,
         * the next section from 1mb->appropriate_mem_k
         */
        sanitize_e820_map(E820_MAP, &E820_MAP_NR);
        if (copy_e820_map(E820_MAP, E820_MAP_NR) < 0) {
                unsigned long mem_size;

                /* compare results from other methods and take the greater */
                if (ALT_MEM_K < EXT_MEM_K) {
                        mem_size = EXT_MEM_K;
                        who = "BIOS-88";
                } else {
                        mem_size = ALT_MEM_K;
                        who = "BIOS-e801";
                }

                e820.nr_map = 0;
                add_memory_region(0, LOWMEMSIZE(), E820_RAM);
                add_memory_region(HIGH_MEMORY, mem_size << 10, E820_RAM);
        }
        printk(KERN_INFO "BIOS-provided physical RAM map:\n");
        e820_print_map(who);
}

#else  /* CONFIG_XEN */

void __init setup_memory_region(void)
{
        int rc;
        struct xen_memory_map memmap;
        /*
         * This is rather large for a stack variable but this early in
         * the boot process we know we have plenty slack space.
         */
        struct e820entry map[E820MAX];

        memmap.nr_entries = E820MAX;
        set_xen_guest_handle(memmap.buffer, map);

        rc = HYPERVISOR_memory_op(XENMEM_memory_map, &memmap);
        if ( rc == -ENOSYS ) {
                memmap.nr_entries = 1;
                map[0].addr = 0ULL;
                map[0].size = xen_start_info->nr_pages << PAGE_SHIFT;
                /* 8MB slack (to balance backend allocations). */
                map[0].size += 8 << 20;
                map[0].type = E820_RAM;
                rc = 0;
        }
        BUG_ON(rc);

        sanitize_e820_map(map, (char *)&memmap.nr_entries);

        BUG_ON(copy_e820_map(map, (char)memmap.nr_entries) < 0);

        printk(KERN_INFO "BIOS-provided physical RAM map:\n");
        e820_print_map("Xen");
}
#endif

void __init parse_memopt(char *p, char **from) 
{ 
        int i;
        unsigned long current_end;
        unsigned long end;

        end_user_pfn = memparse(p, from);
        end_user_pfn >>= PAGE_SHIFT;    

        end = end_user_pfn<<PAGE_SHIFT;
        i = e820.nr_map-1;
        current_end = e820.map[i].addr + e820.map[i].size;

        if (current_end < end) {
                /*
                 * The e820 map ends before our requested size so
                 * extend the final entry to the requested address.
                 */
                if (e820.map[i].type == E820_RAM)
                        e820.map[i].size = end - e820.map[i].addr;
                else
                        add_memory_region(current_end, end - current_end, E820_RAM);
        }
} 

void __init parse_memmapopt(char *p, char **from)
{
        unsigned long long start_at, mem_size;

        mem_size = memparse(p, from);
        p = *from;
        if (*p == '@') {
                start_at = memparse(p+1, from);
                add_memory_region(start_at, mem_size, E820_RAM);
        } else if (*p == '#') {
                start_at = memparse(p+1, from);
                add_memory_region(start_at, mem_size, E820_ACPI);
        } else if (*p == '$') {
                start_at = memparse(p+1, from);
                add_memory_region(start_at, mem_size, E820_RESERVED);
        } else {
                end_user_pfn = (mem_size >> PAGE_SHIFT);
        }
        p = *from;
}

unsigned long pci_mem_start = 0xaeedbabe;
EXPORT_SYMBOL(pci_mem_start);

/*
 * Search for the biggest gap in the low 32 bits of the e820
 * memory space.  We pass this space to PCI to assign MMIO resources
 * for hotplug or unconfigured devices in.
 * Hopefully the BIOS let enough space left.
 */
__init void e820_setup_gap(struct e820entry *e820, int nr_map)
{
        unsigned long gapstart, gapsize, round;
        unsigned long last;
        int i;
        int found = 0;

        last = 0x100000000ull;
        gapstart = 0x10000000;
        gapsize = 0x400000;
        i = nr_map;
        while (--i >= 0) {
                unsigned long long start = e820[i].addr;
                unsigned long long end = start + e820[i].size;

                /*
                 * Since "last" is at most 4GB, we know we'll
                 * fit in 32 bits if this condition is true
                 */
                if (last > end) {
                        unsigned long gap = last - end;

                        if (gap > gapsize) {
                                gapsize = gap;
                                gapstart = end;
                                found = 1;
                        }
                }
                if (start < last)
                        last = start;
        }

        if (!found) {
                gapstart = (end_pfn << PAGE_SHIFT) + 1024*1024;
                printk(KERN_ERR "PCI: Warning: Cannot find a gap in the 32bit address range\n"
                       KERN_ERR "PCI: Unassigned devices with 32bit resource registers may break!\n");
        }

        /*
         * See how much we want to round up: start off with
         * rounding to the next 1MB area.
         */
        round = 0x100000;
        while ((gapsize >> 4) > round)
                round += round;
        /* Fun with two's complement */
        pci_mem_start = (gapstart + round) & -round;

        printk(KERN_INFO "Allocating PCI resources starting at %lx (gap: %lx:%lx)\n",
                pci_mem_start, gapstart, gapsize);
}