[SPARC64]: Add proper header file extern for cmdline_memory_size.

[safe/jmp/linux-2.6] / arch / sparc64 / mm / init.c

/*  $Id: init.c,v 1.209 2002/02/09 19:49:31 davem Exp $
 *  arch/sparc64/mm/init.c
 *
 *  Copyright (C) 1996-1999 David S. Miller (davem@caip.rutgers.edu)
 *  Copyright (C) 1997-1999 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
 */
 
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/mm.h>
#include <linux/hugetlb.h>
#include <linux/slab.h>
#include <linux/initrd.h>
#include <linux/swap.h>
#include <linux/pagemap.h>
#include <linux/poison.h>
#include <linux/fs.h>
#include <linux/seq_file.h>
#include <linux/kprobes.h>
#include <linux/cache.h>
#include <linux/sort.h>

#include <asm/head.h>
#include <asm/system.h>
#include <asm/page.h>
#include <asm/pgalloc.h>
#include <asm/pgtable.h>
#include <asm/oplib.h>
#include <asm/iommu.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/mmu_context.h>
#include <asm/tlbflush.h>
#include <asm/dma.h>
#include <asm/starfire.h>
#include <asm/tlb.h>
#include <asm/spitfire.h>
#include <asm/sections.h>
#include <asm/tsb.h>
#include <asm/hypervisor.h>
#include <asm/prom.h>

extern void device_scan(void);

#define MAX_PHYS_ADDRESS        (1UL << 42UL)
#define KPTE_BITMAP_CHUNK_SZ    (256UL * 1024UL * 1024UL)
#define KPTE_BITMAP_BYTES       \
        ((MAX_PHYS_ADDRESS / KPTE_BITMAP_CHUNK_SZ) / 8)

unsigned long kern_linear_pte_xor[2] __read_mostly;

/* A bitmap, one bit for every 256MB of physical memory.  If the bit
 * is clear, we should use a 4MB page (via kern_linear_pte_xor[0]) else
 * if set we should use a 256MB page (via kern_linear_pte_xor[1]).
 */
unsigned long kpte_linear_bitmap[KPTE_BITMAP_BYTES / sizeof(unsigned long)];

#ifndef CONFIG_DEBUG_PAGEALLOC
/* A special kernel TSB for 4MB and 256MB linear mappings.  */
struct tsb swapper_4m_tsb[KERNEL_TSB4M_NENTRIES];
#endif

#define MAX_BANKS       32

static struct linux_prom64_registers pavail[MAX_BANKS] __initdata;
static struct linux_prom64_registers pavail_rescan[MAX_BANKS] __initdata;
static int pavail_ents __initdata;
static int pavail_rescan_ents __initdata;

static int cmp_p64(const void *a, const void *b)
{
        const struct linux_prom64_registers *x = a, *y = b;

        if (x->phys_addr > y->phys_addr)
                return 1;
        if (x->phys_addr < y->phys_addr)
                return -1;
        return 0;
}

static void __init read_obp_memory(const char *property,
                                   struct linux_prom64_registers *regs,
                                   int *num_ents)
{
        int node = prom_finddevice("/memory");
        int prop_size = prom_getproplen(node, property);
        int ents, ret, i;

        ents = prop_size / sizeof(struct linux_prom64_registers);
        if (ents > MAX_BANKS) {
                prom_printf("The machine has more %s property entries than "
                            "this kernel can support (%d).\n",
                            property, MAX_BANKS);
                prom_halt();
        }

        ret = prom_getproperty(node, property, (char *) regs, prop_size);
        if (ret == -1) {
                prom_printf("Couldn't get %s property from /memory.\n");
                prom_halt();
        }

        /* Sanitize what we got from the firmware, by page aligning
         * everything.
         */
        for (i = 0; i < ents; i++) {
                unsigned long base, size;

                base = regs[i].phys_addr;
                size = regs[i].reg_size;

                size &= PAGE_MASK;
                if (base & ~PAGE_MASK) {
                        unsigned long new_base = PAGE_ALIGN(base);

                        size -= new_base - base;
                        if ((long) size < 0L)
                                size = 0UL;
                        base = new_base;
                }
                if (size == 0UL) {
                        /* If it is empty, simply get rid of it.
                         * This simplifies the logic of the other
                         * functions that process these arrays.
                         */
                        memmove(&regs[i], &regs[i + 1],
                                (ents - i - 1) * sizeof(regs[0]));
                        i--;
                        ents--;
                        continue;
                }
                regs[i].phys_addr = base;
                regs[i].reg_size = size;
        }

        *num_ents = ents;

        sort(regs, ents, sizeof(struct linux_prom64_registers),
             cmp_p64, NULL);
}

unsigned long *sparc64_valid_addr_bitmap __read_mostly;

/* Kernel physical address base and size in bytes.  */
unsigned long kern_base __read_mostly;
unsigned long kern_size __read_mostly;

/* Initial ramdisk setup */
extern unsigned long sparc_ramdisk_image64;
extern unsigned int sparc_ramdisk_image;
extern unsigned int sparc_ramdisk_size;

struct page *mem_map_zero __read_mostly;

unsigned int sparc64_highest_unlocked_tlb_ent __read_mostly;

unsigned long sparc64_kern_pri_context __read_mostly;
unsigned long sparc64_kern_pri_nuc_bits __read_mostly;
unsigned long sparc64_kern_sec_context __read_mostly;

int bigkernel = 0;

struct kmem_cache *pgtable_cache __read_mostly;

static void zero_ctor(void *addr, struct kmem_cache *cache, unsigned long flags)
{
        clear_page(addr);
}

extern void tsb_cache_init(void);

void pgtable_cache_init(void)
{
        pgtable_cache = kmem_cache_create("pgtable_cache",
                                          PAGE_SIZE, PAGE_SIZE,
                                          SLAB_HWCACHE_ALIGN |
                                          SLAB_MUST_HWCACHE_ALIGN,
                                          zero_ctor,
                                          NULL);
        if (!pgtable_cache) {
                prom_printf("Could not create pgtable_cache\n");
                prom_halt();
        }
        tsb_cache_init();
}

#ifdef CONFIG_DEBUG_DCFLUSH
atomic_t dcpage_flushes = ATOMIC_INIT(0);
#ifdef CONFIG_SMP
atomic_t dcpage_flushes_xcall = ATOMIC_INIT(0);
#endif
#endif

inline void flush_dcache_page_impl(struct page *page)
{
        BUG_ON(tlb_type == hypervisor);
#ifdef CONFIG_DEBUG_DCFLUSH
        atomic_inc(&dcpage_flushes);
#endif

#ifdef DCACHE_ALIASING_POSSIBLE
        __flush_dcache_page(page_address(page),
                            ((tlb_type == spitfire) &&
                             page_mapping(page) != NULL));
#else
        if (page_mapping(page) != NULL &&
            tlb_type == spitfire)
                __flush_icache_page(__pa(page_address(page)));
#endif
}

#define PG_dcache_dirty         PG_arch_1
#define PG_dcache_cpu_shift     24UL
#define PG_dcache_cpu_mask      (256UL - 1UL)

#if NR_CPUS > 256
#error D-cache dirty tracking and thread_info->cpu need fixing for > 256 cpus
#endif

#define dcache_dirty_cpu(page) \
        (((page)->flags >> PG_dcache_cpu_shift) & PG_dcache_cpu_mask)

static __inline__ void set_dcache_dirty(struct page *page, int this_cpu)
{
        unsigned long mask = this_cpu;
        unsigned long non_cpu_bits;

        non_cpu_bits = ~(PG_dcache_cpu_mask << PG_dcache_cpu_shift);
        mask = (mask << PG_dcache_cpu_shift) | (1UL << PG_dcache_dirty);

        __asm__ __volatile__("1:\n\t"
                             "ldx       [%2], %%g7\n\t"
                             "and       %%g7, %1, %%g1\n\t"
                             "or        %%g1, %0, %%g1\n\t"
                             "casx      [%2], %%g7, %%g1\n\t"
                             "cmp       %%g7, %%g1\n\t"
                             "membar    #StoreLoad | #StoreStore\n\t"
                             "bne,pn    %%xcc, 1b\n\t"
                             " nop"
                             : /* no outputs */
                             : "r" (mask), "r" (non_cpu_bits), "r" (&page->flags)
                             : "g1", "g7");
}

static __inline__ void clear_dcache_dirty_cpu(struct page *page, unsigned long cpu)
{
        unsigned long mask = (1UL << PG_dcache_dirty);

        __asm__ __volatile__("! test_and_clear_dcache_dirty\n"
                             "1:\n\t"
                             "ldx       [%2], %%g7\n\t"
                             "srlx      %%g7, %4, %%g1\n\t"
                             "and       %%g1, %3, %%g1\n\t"
                             "cmp       %%g1, %0\n\t"
                             "bne,pn    %%icc, 2f\n\t"
                             " andn     %%g7, %1, %%g1\n\t"
                             "casx      [%2], %%g7, %%g1\n\t"
                             "cmp       %%g7, %%g1\n\t"
                             "membar    #StoreLoad | #StoreStore\n\t"
                             "bne,pn    %%xcc, 1b\n\t"
                             " nop\n"
                             "2:"
                             : /* no outputs */
                             : "r" (cpu), "r" (mask), "r" (&page->flags),
                               "i" (PG_dcache_cpu_mask),
                               "i" (PG_dcache_cpu_shift)
                             : "g1", "g7");
}

static inline void tsb_insert(struct tsb *ent, unsigned long tag, unsigned long pte)
{
        unsigned long tsb_addr = (unsigned long) ent;

        if (tlb_type == cheetah_plus || tlb_type == hypervisor)
                tsb_addr = __pa(tsb_addr);

        __tsb_insert(tsb_addr, tag, pte);
}

unsigned long _PAGE_ALL_SZ_BITS __read_mostly;
unsigned long _PAGE_SZBITS __read_mostly;

void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t pte)
{
        struct mm_struct *mm;
        struct tsb *tsb;
        unsigned long tag, flags;
        unsigned long tsb_index, tsb_hash_shift;

        if (tlb_type != hypervisor) {
                unsigned long pfn = pte_pfn(pte);
                unsigned long pg_flags;
                struct page *page;

                if (pfn_valid(pfn) &&
                    (page = pfn_to_page(pfn), page_mapping(page)) &&
                    ((pg_flags = page->flags) & (1UL << PG_dcache_dirty))) {
                        int cpu = ((pg_flags >> PG_dcache_cpu_shift) &
                                   PG_dcache_cpu_mask);
                        int this_cpu = get_cpu();

                        /* This is just to optimize away some function calls
                         * in the SMP case.
                         */
                        if (cpu == this_cpu)
                                flush_dcache_page_impl(page);
                        else
                                smp_flush_dcache_page_impl(page, cpu);

                        clear_dcache_dirty_cpu(page, cpu);

                        put_cpu();
                }
        }

        mm = vma->vm_mm;

        tsb_index = MM_TSB_BASE;
        tsb_hash_shift = PAGE_SHIFT;

        spin_lock_irqsave(&mm->context.lock, flags);

#ifdef CONFIG_HUGETLB_PAGE
        if (mm->context.tsb_block[MM_TSB_HUGE].tsb != NULL) {
                if ((tlb_type == hypervisor &&
                     (pte_val(pte) & _PAGE_SZALL_4V) == _PAGE_SZHUGE_4V) ||
                    (tlb_type != hypervisor &&
                     (pte_val(pte) & _PAGE_SZALL_4U) == _PAGE_SZHUGE_4U)) {
                        tsb_index = MM_TSB_HUGE;
                        tsb_hash_shift = HPAGE_SHIFT;
                }
        }
#endif

        tsb = mm->context.tsb_block[tsb_index].tsb;
        tsb += ((address >> tsb_hash_shift) &
                (mm->context.tsb_block[tsb_index].tsb_nentries - 1UL));
        tag = (address >> 22UL);
        tsb_insert(tsb, tag, pte_val(pte));

        spin_unlock_irqrestore(&mm->context.lock, flags);
}

void flush_dcache_page(struct page *page)
{
        struct address_space *mapping;
        int this_cpu;

        if (tlb_type == hypervisor)
                return;

        /* Do not bother with the expensive D-cache flush if it
         * is merely the zero page.  The 'bigcore' testcase in GDB
         * causes this case to run millions of times.
         */
        if (page == ZERO_PAGE(0))
                return;

        this_cpu = get_cpu();

        mapping = page_mapping(page);
        if (mapping && !mapping_mapped(mapping)) {
                int dirty = test_bit(PG_dcache_dirty, &page->flags);
                if (dirty) {
                        int dirty_cpu = dcache_dirty_cpu(page);

                        if (dirty_cpu == this_cpu)
                                goto out;
                        smp_flush_dcache_page_impl(page, dirty_cpu);
                }
                set_dcache_dirty(page, this_cpu);
        } else {
                /* We could delay the flush for the !page_mapping
                 * case too.  But that case is for exec env/arg
                 * pages and those are %99 certainly going to get
                 * faulted into the tlb (and thus flushed) anyways.
                 */
                flush_dcache_page_impl(page);
        }

out:
        put_cpu();
}

void __kprobes flush_icache_range(unsigned long start, unsigned long end)
{
        /* Cheetah and Hypervisor platform cpus have coherent I-cache. */
        if (tlb_type == spitfire) {
                unsigned long kaddr;

                /* This code only runs on Spitfire cpus so this is
                 * why we can assume _PAGE_PADDR_4U.
                 */
                for (kaddr = start; kaddr < end; kaddr += PAGE_SIZE) {
                        unsigned long paddr, mask = _PAGE_PADDR_4U;

                        if (kaddr >= PAGE_OFFSET)
                                paddr = kaddr & mask;
                        else {
                                pgd_t *pgdp = pgd_offset_k(kaddr);
                                pud_t *pudp = pud_offset(pgdp, kaddr);
                                pmd_t *pmdp = pmd_offset(pudp, kaddr);
                                pte_t *ptep = pte_offset_kernel(pmdp, kaddr);

                                paddr = pte_val(*ptep) & mask;
                        }
                        __flush_icache_page(paddr);
                }
        }
}

void show_mem(void)
{
        unsigned long total = 0, reserved = 0;
        unsigned long shared = 0, cached = 0;
        pg_data_t *pgdat;

        printk(KERN_INFO "Mem-info:\n");
        show_free_areas();
        printk(KERN_INFO "Free swap:       %6ldkB\n",
               nr_swap_pages << (PAGE_SHIFT-10));
        for_each_online_pgdat(pgdat) {
                unsigned long i, flags;

                pgdat_resize_lock(pgdat, &flags);
                for (i = 0; i < pgdat->node_spanned_pages; i++) {
                        struct page *page = pgdat_page_nr(pgdat, i);
                        total++;
                        if (PageReserved(page))
                                reserved++;
                        else if (PageSwapCache(page))
                                cached++;
                        else if (page_count(page))
                                shared += page_count(page) - 1;
                }
                pgdat_resize_unlock(pgdat, &flags);
        }

        printk(KERN_INFO "%lu pages of RAM\n", total);
        printk(KERN_INFO "%lu reserved pages\n", reserved);
        printk(KERN_INFO "%lu pages shared\n", shared);
        printk(KERN_INFO "%lu pages swap cached\n", cached);

        printk(KERN_INFO "%lu pages dirty\n",
               global_page_state(NR_FILE_DIRTY));
        printk(KERN_INFO "%lu pages writeback\n",
               global_page_state(NR_WRITEBACK));
        printk(KERN_INFO "%lu pages mapped\n",
               global_page_state(NR_FILE_MAPPED));
        printk(KERN_INFO "%lu pages slab\n",
                global_page_state(NR_SLAB_RECLAIMABLE) +
                global_page_state(NR_SLAB_UNRECLAIMABLE));
        printk(KERN_INFO "%lu pages pagetables\n",
               global_page_state(NR_PAGETABLE));
}

void mmu_info(struct seq_file *m)
{
        if (tlb_type == cheetah)
                seq_printf(m, "MMU Type\t: Cheetah\n");
        else if (tlb_type == cheetah_plus)
                seq_printf(m, "MMU Type\t: Cheetah+\n");
        else if (tlb_type == spitfire)
                seq_printf(m, "MMU Type\t: Spitfire\n");
        else if (tlb_type == hypervisor)
                seq_printf(m, "MMU Type\t: Hypervisor (sun4v)\n");
        else
                seq_printf(m, "MMU Type\t: ???\n");

#ifdef CONFIG_DEBUG_DCFLUSH
        seq_printf(m, "DCPageFlushes\t: %d\n",
                   atomic_read(&dcpage_flushes));
#ifdef CONFIG_SMP
        seq_printf(m, "DCPageFlushesXC\t: %d\n",
                   atomic_read(&dcpage_flushes_xcall));
#endif /* CONFIG_SMP */
#endif /* CONFIG_DEBUG_DCFLUSH */
}

struct linux_prom_translation {
        unsigned long virt;
        unsigned long size;
        unsigned long data;
};

/* Exported for kernel TLB miss handling in ktlb.S */
struct linux_prom_translation prom_trans[512] __read_mostly;
unsigned int prom_trans_ents __read_mostly;

/* Exported for SMP bootup purposes. */
unsigned long kern_locked_tte_data;

/* The obp translations are saved based on 8k pagesize, since obp can
 * use a mixture of pagesizes. Misses to the LOW_OBP_ADDRESS ->
 * HI_OBP_ADDRESS range are handled in ktlb.S.
 */
static inline int in_obp_range(unsigned long vaddr)
{
        return (vaddr >= LOW_OBP_ADDRESS &&
                vaddr < HI_OBP_ADDRESS);
}

static int cmp_ptrans(const void *a, const void *b)
{
        const struct linux_prom_translation *x = a, *y = b;

        if (x->virt > y->virt)
                return 1;
        if (x->virt < y->virt)
                return -1;
        return 0;
}

/* Read OBP translations property into 'prom_trans[]'.  */
static void __init read_obp_translations(void)
{
        int n, node, ents, first, last, i;

        node = prom_finddevice("/virtual-memory");
        n = prom_getproplen(node, "translations");
        if (unlikely(n == 0 || n == -1)) {
                prom_printf("prom_mappings: Couldn't get size.\n");
                prom_halt();
        }
        if (unlikely(n > sizeof(prom_trans))) {
                prom_printf("prom_mappings: Size %Zd is too big.\n", n);
                prom_halt();
        }

        if ((n = prom_getproperty(node, "translations",
                                  (char *)&prom_trans[0],
                                  sizeof(prom_trans))) == -1) {
                prom_printf("prom_mappings: Couldn't get property.\n");
                prom_halt();
        }

        n = n / sizeof(struct linux_prom_translation);

        ents = n;

        sort(prom_trans, ents, sizeof(struct linux_prom_translation),
             cmp_ptrans, NULL);

        /* Now kick out all the non-OBP entries.  */
        for (i = 0; i < ents; i++) {
                if (in_obp_range(prom_trans[i].virt))
                        break;
        }
        first = i;
        for (; i < ents; i++) {
                if (!in_obp_range(prom_trans[i].virt))
                        break;
        }
        last = i;

        for (i = 0; i < (last - first); i++) {
                struct linux_prom_translation *src = &prom_trans[i + first];
                struct linux_prom_translation *dest = &prom_trans[i];

                *dest = *src;
        }
        for (; i < ents; i++) {
                struct linux_prom_translation *dest = &prom_trans[i];
                dest->virt = dest->size = dest->data = 0x0UL;
        }

        prom_trans_ents = last - first;

        if (tlb_type == spitfire) {
                /* Clear diag TTE bits. */
                for (i = 0; i < prom_trans_ents; i++)
                        prom_trans[i].data &= ~0x0003fe0000000000UL;
        }
}

static void __init hypervisor_tlb_lock(unsigned long vaddr,
                                       unsigned long pte,
                                       unsigned long mmu)
{
        register unsigned long func asm("%o5");
        register unsigned long arg0 asm("%o0");
        register unsigned long arg1 asm("%o1");
        register unsigned long arg2 asm("%o2");
        register unsigned long arg3 asm("%o3");

        func = HV_FAST_MMU_MAP_PERM_ADDR;
        arg0 = vaddr;
        arg1 = 0;
        arg2 = pte;
        arg3 = mmu;
        __asm__ __volatile__("ta        0x80"
                             : "=&r" (func), "=&r" (arg0),
                               "=&r" (arg1), "=&r" (arg2),
                               "=&r" (arg3)
                             : "0" (func), "1" (arg0), "2" (arg1),
                               "3" (arg2), "4" (arg3));
        if (arg0 != 0) {
                prom_printf("hypervisor_tlb_lock[%lx:%lx:%lx:%lx]: "
                            "errors with %lx\n", vaddr, 0, pte, mmu, arg0);
                prom_halt();
        }
}

static unsigned long kern_large_tte(unsigned long paddr);

static void __init remap_kernel(void)
{
        unsigned long phys_page, tte_vaddr, tte_data;
        int tlb_ent = sparc64_highest_locked_tlbent();

        tte_vaddr = (unsigned long) KERNBASE;
        phys_page = (prom_boot_mapping_phys_low >> 22UL) << 22UL;
        tte_data = kern_large_tte(phys_page);

        kern_locked_tte_data = tte_data;

        /* Now lock us into the TLBs via Hypervisor or OBP. */
        if (tlb_type == hypervisor) {
                hypervisor_tlb_lock(tte_vaddr, tte_data, HV_MMU_DMMU);
                hypervisor_tlb_lock(tte_vaddr, tte_data, HV_MMU_IMMU);
                if (bigkernel) {
                        tte_vaddr += 0x400000;
                        tte_data += 0x400000;
                        hypervisor_tlb_lock(tte_vaddr, tte_data, HV_MMU_DMMU);
                        hypervisor_tlb_lock(tte_vaddr, tte_data, HV_MMU_IMMU);
                }
        } else {
                prom_dtlb_load(tlb_ent, tte_data, tte_vaddr);
                prom_itlb_load(tlb_ent, tte_data, tte_vaddr);
                if (bigkernel) {
                        tlb_ent -= 1;
                        prom_dtlb_load(tlb_ent,
                                       tte_data + 0x400000, 
                                       tte_vaddr + 0x400000);
                        prom_itlb_load(tlb_ent,
                                       tte_data + 0x400000, 
                                       tte_vaddr + 0x400000);
                }
                sparc64_highest_unlocked_tlb_ent = tlb_ent - 1;
        }
        if (tlb_type == cheetah_plus) {
                sparc64_kern_pri_context = (CTX_CHEETAH_PLUS_CTX0 |
                                            CTX_CHEETAH_PLUS_NUC);
                sparc64_kern_pri_nuc_bits = CTX_CHEETAH_PLUS_NUC;
                sparc64_kern_sec_context = CTX_CHEETAH_PLUS_CTX0;
        }
}


static void __init inherit_prom_mappings(void)
{
        read_obp_translations();

        /* Now fixup OBP's idea about where we really are mapped. */
        prom_printf("Remapping the kernel... ");
        remap_kernel();
        prom_printf("done.\n");
}

void prom_world(int enter)
{
        if (!enter)
                set_fs((mm_segment_t) { get_thread_current_ds() });

        __asm__ __volatile__("flushw");
}

#ifdef DCACHE_ALIASING_POSSIBLE
void __flush_dcache_range(unsigned long start, unsigned long end)
{
        unsigned long va;

        if (tlb_type == spitfire) {
                int n = 0;

                for (va = start; va < end; va += 32) {
                        spitfire_put_dcache_tag(va & 0x3fe0, 0x0);
                        if (++n >= 512)
                                break;
                }
        } else if (tlb_type == cheetah || tlb_type == cheetah_plus) {
                start = __pa(start);
                end = __pa(end);
                for (va = start; va < end; va += 32)
                        __asm__ __volatile__("stxa %%g0, [%0] %1\n\t"
                                             "membar #Sync"
                                             : /* no outputs */
                                             : "r" (va),
                                               "i" (ASI_DCACHE_INVALIDATE));
        }
}
#endif /* DCACHE_ALIASING_POSSIBLE */

/* get_new_mmu_context() uses "cache + 1".  */
DEFINE_SPINLOCK(ctx_alloc_lock);
unsigned long tlb_context_cache = CTX_FIRST_VERSION - 1;
#define MAX_CTX_NR      (1UL << CTX_NR_BITS)
#define CTX_BMAP_SLOTS  BITS_TO_LONGS(MAX_CTX_NR)
DECLARE_BITMAP(mmu_context_bmap, MAX_CTX_NR);

/* Caller does TLB context flushing on local CPU if necessary.
 * The caller also ensures that CTX_VALID(mm->context) is false.
 *
 * We must be careful about boundary cases so that we never
 * let the user have CTX 0 (nucleus) or we ever use a CTX
 * version of zero (and thus NO_CONTEXT would not be caught
 * by version mis-match tests in mmu_context.h).
 *
 * Always invoked with interrupts disabled.
 */
void get_new_mmu_context(struct mm_struct *mm)
{
        unsigned long ctx, new_ctx;
        unsigned long orig_pgsz_bits;
        unsigned long flags;
        int new_version;

        spin_lock_irqsave(&ctx_alloc_lock, flags);
        orig_pgsz_bits = (mm->context.sparc64_ctx_val & CTX_PGSZ_MASK);
        ctx = (tlb_context_cache + 1) & CTX_NR_MASK;
        new_ctx = find_next_zero_bit(mmu_context_bmap, 1 << CTX_NR_BITS, ctx);
        new_version = 0;
        if (new_ctx >= (1 << CTX_NR_BITS)) {
                new_ctx = find_next_zero_bit(mmu_context_bmap, ctx, 1);
                if (new_ctx >= ctx) {
                        int i;
                        new_ctx = (tlb_context_cache & CTX_VERSION_MASK) +
                                CTX_FIRST_VERSION;
                        if (new_ctx == 1)
                                new_ctx = CTX_FIRST_VERSION;

                        /* Don't call memset, for 16 entries that's just
                         * plain silly...
                         */
                        mmu_context_bmap[0] = 3;
                        mmu_context_bmap[1] = 0;
                        mmu_context_bmap[2] = 0;
                        mmu_context_bmap[3] = 0;
                        for (i = 4; i < CTX_BMAP_SLOTS; i += 4) {
                                mmu_context_bmap[i + 0] = 0;
                                mmu_context_bmap[i + 1] = 0;
                                mmu_context_bmap[i + 2] = 0;
                                mmu_context_bmap[i + 3] = 0;
                        }
                        new_version = 1;
                        goto out;
                }
        }
        mmu_context_bmap[new_ctx>>6] |= (1UL << (new_ctx & 63));
        new_ctx |= (tlb_context_cache & CTX_VERSION_MASK);
out:
        tlb_context_cache = new_ctx;
        mm->context.sparc64_ctx_val = new_ctx | orig_pgsz_bits;
        spin_unlock_irqrestore(&ctx_alloc_lock, flags);

        if (unlikely(new_version))
                smp_new_mmu_context_version();
}

/* Find a free area for the bootmem map, avoiding the kernel image
 * and the initial ramdisk.
 */
static unsigned long __init choose_bootmap_pfn(unsigned long start_pfn,
                                               unsigned long end_pfn)
{
        unsigned long avoid_start, avoid_end, bootmap_size;
        int i;

        bootmap_size = ((end_pfn - start_pfn) + 7) / 8;
        bootmap_size = ALIGN(bootmap_size, sizeof(long));

        avoid_start = avoid_end = 0;
#ifdef CONFIG_BLK_DEV_INITRD
        avoid_start = initrd_start;
        avoid_end = PAGE_ALIGN(initrd_end);
#endif

#ifdef CONFIG_DEBUG_BOOTMEM
        prom_printf("choose_bootmap_pfn: kern[%lx:%lx] avoid[%lx:%lx]\n",
                    kern_base, PAGE_ALIGN(kern_base + kern_size),
                    avoid_start, avoid_end);
#endif
        for (i = 0; i < pavail_ents; i++) {
                unsigned long start, end;

                start = pavail[i].phys_addr;
                end = start + pavail[i].reg_size;

                while (start < end) {
                        if (start >= kern_base &&
                            start < PAGE_ALIGN(kern_base + kern_size)) {
                                start = PAGE_ALIGN(kern_base + kern_size);
                                continue;
                        }
                        if (start >= avoid_start && start < avoid_end) {
                                start = avoid_end;
                                continue;
                        }

                        if ((end - start) < bootmap_size)
                                break;

                        if (start < kern_base &&
                            (start + bootmap_size) > kern_base) {
                                start = PAGE_ALIGN(kern_base + kern_size);
                                continue;
                        }

                        if (start < avoid_start &&
                            (start + bootmap_size) > avoid_start) {
                                start = avoid_end;
                                continue;
                        }

                        /* OK, it doesn't overlap anything, use it.  */
#ifdef CONFIG_DEBUG_BOOTMEM
                        prom_printf("choose_bootmap_pfn: Using %lx [%lx]\n",
                                    start >> PAGE_SHIFT, start);
#endif
                        return start >> PAGE_SHIFT;
                }
        }

        prom_printf("Cannot find free area for bootmap, aborting.\n");
        prom_halt();
}

static void __init trim_pavail(unsigned long *cur_size_p,
                               unsigned long *end_of_phys_p)
{
        unsigned long to_trim = *cur_size_p - cmdline_memory_size;
        unsigned long avoid_start, avoid_end;
        int i;

        to_trim = PAGE_ALIGN(to_trim);

        avoid_start = avoid_end = 0;
#ifdef CONFIG_BLK_DEV_INITRD
        avoid_start = initrd_start;
        avoid_end = PAGE_ALIGN(initrd_end);
#endif

        /* Trim some pavail[] entries in order to satisfy the
         * requested "mem=xxx" kernel command line specification.
         *
         * We must not trim off the kernel image area nor the
         * initial ramdisk range (if any).  Also, we must not trim
         * any pavail[] entry down to zero in order to preserve
         * the invariant that all pavail[] entries have a non-zero
         * size which is assumed by all of the code in here.
         */
        for (i = 0; i < pavail_ents; i++) {
                unsigned long start, end, kern_end;
                unsigned long trim_low, trim_high, n;

                kern_end = PAGE_ALIGN(kern_base + kern_size);

                trim_low = start = pavail[i].phys_addr;
                trim_high = end = start + pavail[i].reg_size;

                if (kern_base >= start &&
                    kern_base < end) {
                        trim_low = kern_base;
                        if (kern_end >= end)
                                continue;
                }
                if (kern_end >= start &&
                    kern_end < end) {
                        trim_high = kern_end;
                }
                if (avoid_start &&
                    avoid_start >= start &&
                    avoid_start < end) {
                        if (trim_low > avoid_start)
                                trim_low = avoid_start;
                        if (avoid_end >= end)
                                continue;
                }
                if (avoid_end &&
                    avoid_end >= start &&
                    avoid_end < end) {
                        if (trim_high < avoid_end)
                                trim_high = avoid_end;
                }

                if (trim_high <= trim_low)
                        continue;

                if (trim_low == start && trim_high == end) {
                        /* Whole chunk is available for trimming.
                         * Trim all except one page, in order to keep
                         * entry non-empty.
                         */
                        n = (end - start) - PAGE_SIZE;
                        if (n > to_trim)
                                n = to_trim;

                        if (n) {
                                pavail[i].phys_addr += n;
                                pavail[i].reg_size -= n;
                                to_trim -= n;
                        }
                } else {
                        n = (trim_low - start);
                        if (n > to_trim)
                                n = to_trim;

                        if (n) {
                                pavail[i].phys_addr += n;
                                pavail[i].reg_size -= n;
                                to_trim -= n;
                        }
                        if (to_trim) {
                                n = end - trim_high;
                                if (n > to_trim)
                                        n = to_trim;
                                if (n) {
                                        pavail[i].reg_size -= n;
                                        to_trim -= n;
                                }
                        }
                }

                if (!to_trim)
                        break;
        }

        /* Recalculate.  */
        *cur_size_p = 0UL;
        for (i = 0; i < pavail_ents; i++) {
                *end_of_phys_p = pavail[i].phys_addr +
                        pavail[i].reg_size;
                *cur_size_p += pavail[i].reg_size;
        }
}

static unsigned long __init bootmem_init(unsigned long *pages_avail,
                                         unsigned long phys_base)
{
        unsigned long bootmap_size, end_pfn;
        unsigned long end_of_phys_memory = 0UL;
        unsigned long bootmap_pfn, bytes_avail, size;
        int i;

#ifdef CONFIG_DEBUG_BOOTMEM
        prom_printf("bootmem_init: Scan pavail, ");
#endif

        bytes_avail = 0UL;
        for (i = 0; i < pavail_ents; i++) {
                end_of_phys_memory = pavail[i].phys_addr +
                        pavail[i].reg_size;
                bytes_avail += pavail[i].reg_size;
        }

        /* Determine the location of the initial ramdisk before trying
         * to honor the "mem=xxx" command line argument.  We must know
         * where the kernel image and the ramdisk image are so that we
         * do not trim those two areas from the physical memory map.
         */

#ifdef CONFIG_BLK_DEV_INITRD
        /* Now have to check initial ramdisk, so that bootmap does not overwrite it */
        if (sparc_ramdisk_image || sparc_ramdisk_image64) {
                unsigned long ramdisk_image = sparc_ramdisk_image ?
                        sparc_ramdisk_image : sparc_ramdisk_image64;
                ramdisk_image -= KERNBASE;
                initrd_start = ramdisk_image + phys_base;
                initrd_end = initrd_start + sparc_ramdisk_size;
                if (initrd_end > end_of_phys_memory) {
                        printk(KERN_CRIT "initrd extends beyond end of memory "
                                         "(0x%016lx > 0x%016lx)\ndisabling initrd\n",
                               initrd_end, end_of_phys_memory);
                        initrd_start = 0;
                        initrd_end = 0;
                }
        }
#endif  

        if (cmdline_memory_size &&
            bytes_avail > cmdline_memory_size)
                trim_pavail(&bytes_avail,
                            &end_of_phys_memory);

        *pages_avail = bytes_avail >> PAGE_SHIFT;

        end_pfn = end_of_phys_memory >> PAGE_SHIFT;

        /* Initialize the boot-time allocator. */
        max_pfn = max_low_pfn = end_pfn;
        min_low_pfn = (phys_base >> PAGE_SHIFT);

        bootmap_pfn = choose_bootmap_pfn(min_low_pfn, end_pfn);

#ifdef CONFIG_DEBUG_BOOTMEM
        prom_printf("init_bootmem(min[%lx], bootmap[%lx], max[%lx])\n",
                    min_low_pfn, bootmap_pfn, max_low_pfn);
#endif
        bootmap_size = init_bootmem_node(NODE_DATA(0), bootmap_pfn,
                                         min_low_pfn, end_pfn);

        /* Now register the available physical memory with the
         * allocator.
         */
        for (i = 0; i < pavail_ents; i++) {
#ifdef CONFIG_DEBUG_BOOTMEM
                prom_printf("free_bootmem(pavail:%d): base[%lx] size[%lx]\n",
                            i, pavail[i].phys_addr, pavail[i].reg_size);
#endif
                free_bootmem(pavail[i].phys_addr, pavail[i].reg_size);
        }

#ifdef CONFIG_BLK_DEV_INITRD
        if (initrd_start) {
                size = initrd_end - initrd_start;

                /* Resert the initrd image area. */
#ifdef CONFIG_DEBUG_BOOTMEM
                prom_printf("reserve_bootmem(initrd): base[%llx] size[%lx]\n",
                        initrd_start, initrd_end);
#endif
                reserve_bootmem(initrd_start, size);
                *pages_avail -= PAGE_ALIGN(size) >> PAGE_SHIFT;

                initrd_start += PAGE_OFFSET;
                initrd_end += PAGE_OFFSET;
        }
#endif
        /* Reserve the kernel text/data/bss. */
#ifdef CONFIG_DEBUG_BOOTMEM
        prom_printf("reserve_bootmem(kernel): base[%lx] size[%lx]\n", kern_base, kern_size);
#endif
        reserve_bootmem(kern_base, kern_size);
        *pages_avail -= PAGE_ALIGN(kern_size) >> PAGE_SHIFT;

        /* Reserve the bootmem map.   We do not account for it
         * in pages_avail because we will release that memory
         * in free_all_bootmem.
         */
        size = bootmap_size;
#ifdef CONFIG_DEBUG_BOOTMEM
        prom_printf("reserve_bootmem(bootmap): base[%lx] size[%lx]\n",
                    (bootmap_pfn << PAGE_SHIFT), size);
#endif
        reserve_bootmem((bootmap_pfn << PAGE_SHIFT), size);
        *pages_avail -= PAGE_ALIGN(size) >> PAGE_SHIFT;

        for (i = 0; i < pavail_ents; i++) {
                unsigned long start_pfn, end_pfn;

                start_pfn = pavail[i].phys_addr >> PAGE_SHIFT;
                end_pfn = (start_pfn + (pavail[i].reg_size >> PAGE_SHIFT));
#ifdef CONFIG_DEBUG_BOOTMEM
                prom_printf("memory_present(0, %lx, %lx)\n",
                            start_pfn, end_pfn);
#endif
                memory_present(0, start_pfn, end_pfn);
        }

        sparse_init();

        return end_pfn;
}

static struct linux_prom64_registers pall[MAX_BANKS] __initdata;
static int pall_ents __initdata;

#ifdef CONFIG_DEBUG_PAGEALLOC
static unsigned long kernel_map_range(unsigned long pstart, unsigned long pend, pgprot_t prot)
{
        unsigned long vstart = PAGE_OFFSET + pstart;
        unsigned long vend = PAGE_OFFSET + pend;
        unsigned long alloc_bytes = 0UL;

        if ((vstart & ~PAGE_MASK) || (vend & ~PAGE_MASK)) {
                prom_printf("kernel_map: Unaligned physmem[%lx:%lx]\n",
                            vstart, vend);
                prom_halt();
        }

        while (vstart < vend) {
                unsigned long this_end, paddr = __pa(vstart);
                pgd_t *pgd = pgd_offset_k(vstart);
                pud_t *pud;
                pmd_t *pmd;
                pte_t *pte;

                pud = pud_offset(pgd, vstart);
                if (pud_none(*pud)) {
                        pmd_t *new;

                        new = __alloc_bootmem(PAGE_SIZE, PAGE_SIZE, PAGE_SIZE);
                        alloc_bytes += PAGE_SIZE;
                        pud_populate(&init_mm, pud, new);
                }

                pmd = pmd_offset(pud, vstart);
                if (!pmd_present(*pmd)) {
                        pte_t *new;

                        new = __alloc_bootmem(PAGE_SIZE, PAGE_SIZE, PAGE_SIZE);
                        alloc_bytes += PAGE_SIZE;
                        pmd_populate_kernel(&init_mm, pmd, new);
                }

                pte = pte_offset_kernel(pmd, vstart);
                this_end = (vstart + PMD_SIZE) & PMD_MASK;
                if (this_end > vend)
                        this_end = vend;

                while (vstart < this_end) {
                        pte_val(*pte) = (paddr | pgprot_val(prot));

                        vstart += PAGE_SIZE;
                        paddr += PAGE_SIZE;
                        pte++;
                }
        }

        return alloc_bytes;
}

extern unsigned int kvmap_linear_patch[1];
#endif /* CONFIG_DEBUG_PAGEALLOC */

static void __init mark_kpte_bitmap(unsigned long start, unsigned long end)
{
        const unsigned long shift_256MB = 28;
        const unsigned long mask_256MB = ((1UL << shift_256MB) - 1UL);
        const unsigned long size_256MB = (1UL << shift_256MB);

        while (start < end) {
                long remains;

                remains = end - start;
                if (remains < size_256MB)
                        break;

                if (start & mask_256MB) {
                        start = (start + size_256MB) & ~mask_256MB;
                        continue;
                }

                while (remains >= size_256MB) {
                        unsigned long index = start >> shift_256MB;

                        __set_bit(index, kpte_linear_bitmap);

                        start += size_256MB;
                        remains -= size_256MB;
                }
        }
}

static void __init kernel_physical_mapping_init(void)
{
        unsigned long i;
#ifdef CONFIG_DEBUG_PAGEALLOC
        unsigned long mem_alloced = 0UL;
#endif

        read_obp_memory("reg", &pall[0], &pall_ents);

        for (i = 0; i < pall_ents; i++) {
                unsigned long phys_start, phys_end;

                phys_start = pall[i].phys_addr;
                phys_end = phys_start + pall[i].reg_size;

                mark_kpte_bitmap(phys_start, phys_end);

#ifdef CONFIG_DEBUG_PAGEALLOC
                mem_alloced += kernel_map_range(phys_start, phys_end,
                                                PAGE_KERNEL);
#endif
        }

#ifdef CONFIG_DEBUG_PAGEALLOC
        printk("Allocated %ld bytes for kernel page tables.\n",
               mem_alloced);

        kvmap_linear_patch[0] = 0x01000000; /* nop */
        flushi(&kvmap_linear_patch[0]);

        __flush_tlb_all();
#endif
}

#ifdef CONFIG_DEBUG_PAGEALLOC
void kernel_map_pages(struct page *page, int numpages, int enable)
{
        unsigned long phys_start = page_to_pfn(page) << PAGE_SHIFT;
        unsigned long phys_end = phys_start + (numpages * PAGE_SIZE);

        kernel_map_range(phys_start, phys_end,
                         (enable ? PAGE_KERNEL : __pgprot(0)));

        flush_tsb_kernel_range(PAGE_OFFSET + phys_start,
                               PAGE_OFFSET + phys_end);

        /* we should perform an IPI and flush all tlbs,
         * but that can deadlock->flush only current cpu.
         */
        __flush_tlb_kernel_range(PAGE_OFFSET + phys_start,
                                 PAGE_OFFSET + phys_end);
}
#endif

unsigned long __init find_ecache_flush_span(unsigned long size)
{
        int i;

        for (i = 0; i < pavail_ents; i++) {
                if (pavail[i].reg_size >= size)
                        return pavail[i].phys_addr;
        }

        return ~0UL;
}

static void __init tsb_phys_patch(void)
{
        struct tsb_ldquad_phys_patch_entry *pquad;
        struct tsb_phys_patch_entry *p;

        pquad = &__tsb_ldquad_phys_patch;
        while (pquad < &__tsb_ldquad_phys_patch_end) {
                unsigned long addr = pquad->addr;

                if (tlb_type == hypervisor)
                        *(unsigned int *) addr = pquad->sun4v_insn;
                else
                        *(unsigned int *) addr = pquad->sun4u_insn;
                wmb();
                __asm__ __volatile__("flush     %0"
                                     : /* no outputs */
                                     : "r" (addr));

                pquad++;
        }

        p = &__tsb_phys_patch;
        while (p < &__tsb_phys_patch_end) {
                unsigned long addr = p->addr;

                *(unsigned int *) addr = p->insn;
                wmb();
                __asm__ __volatile__("flush     %0"
                                     : /* no outputs */
                                     : "r" (addr));

                p++;
        }
}

/* Don't mark as init, we give this to the Hypervisor.  */
#ifndef CONFIG_DEBUG_PAGEALLOC
#define NUM_KTSB_DESCR  2
#else
#define NUM_KTSB_DESCR  1
#endif
static struct hv_tsb_descr ktsb_descr[NUM_KTSB_DESCR];
extern struct tsb swapper_tsb[KERNEL_TSB_NENTRIES];

static void __init sun4v_ktsb_init(void)
{
        unsigned long ktsb_pa;

        /* First KTSB for PAGE_SIZE mappings.  */
        ktsb_pa = kern_base + ((unsigned long)&swapper_tsb[0] - KERNBASE);

        switch (PAGE_SIZE) {
        case 8 * 1024:
        default:
                ktsb_descr[0].pgsz_idx = HV_PGSZ_IDX_8K;
                ktsb_descr[0].pgsz_mask = HV_PGSZ_MASK_8K;
                break;

        case 64 * 1024:
                ktsb_descr[0].pgsz_idx = HV_PGSZ_IDX_64K;
                ktsb_descr[0].pgsz_mask = HV_PGSZ_MASK_64K;
                break;

        case 512 * 1024:
                ktsb_descr[0].pgsz_idx = HV_PGSZ_IDX_512K;
                ktsb_descr[0].pgsz_mask = HV_PGSZ_MASK_512K;
                break;

        case 4 * 1024 * 1024:
                ktsb_descr[0].pgsz_idx = HV_PGSZ_IDX_4MB;
                ktsb_descr[0].pgsz_mask = HV_PGSZ_MASK_4MB;
                break;
        };

        ktsb_descr[0].assoc = 1;
        ktsb_descr[0].num_ttes = KERNEL_TSB_NENTRIES;
        ktsb_descr[0].ctx_idx = 0;
        ktsb_descr[0].tsb_base = ktsb_pa;
        ktsb_descr[0].resv = 0;

#ifndef CONFIG_DEBUG_PAGEALLOC
        /* Second KTSB for 4MB/256MB mappings.  */
        ktsb_pa = (kern_base +
                   ((unsigned long)&swapper_4m_tsb[0] - KERNBASE));

        ktsb_descr[1].pgsz_idx = HV_PGSZ_IDX_4MB;
        ktsb_descr[1].pgsz_mask = (HV_PGSZ_MASK_4MB |
                                   HV_PGSZ_MASK_256MB);
        ktsb_descr[1].assoc = 1;
        ktsb_descr[1].num_ttes = KERNEL_TSB4M_NENTRIES;
        ktsb_descr[1].ctx_idx = 0;
        ktsb_descr[1].tsb_base = ktsb_pa;
        ktsb_descr[1].resv = 0;
#endif
}

void __cpuinit sun4v_ktsb_register(void)
{
        register unsigned long func asm("%o5");
        register unsigned long arg0 asm("%o0");
        register unsigned long arg1 asm("%o1");
        unsigned long pa;

        pa = kern_base + ((unsigned long)&ktsb_descr[0] - KERNBASE);

        func = HV_FAST_MMU_TSB_CTX0;
        arg0 = NUM_KTSB_DESCR;
        arg1 = pa;
        __asm__ __volatile__("ta        %6"
                             : "=&r" (func), "=&r" (arg0), "=&r" (arg1)
                             : "0" (func), "1" (arg0), "2" (arg1),
                               "i" (HV_FAST_TRAP));
}

/* paging_init() sets up the page tables */

extern void cheetah_ecache_flush_init(void);
extern void sun4v_patch_tlb_handlers(void);

static unsigned long last_valid_pfn;
pgd_t swapper_pg_dir[2048];

static void sun4u_pgprot_init(void);
static void sun4v_pgprot_init(void);

void __init paging_init(void)
{
        unsigned long end_pfn, pages_avail, shift, phys_base;
        unsigned long real_end, i;

        kern_base = (prom_boot_mapping_phys_low >> 22UL) << 22UL;
        kern_size = (unsigned long)&_end - (unsigned long)KERNBASE;

        /* Invalidate both kernel TSBs.  */
        memset(swapper_tsb, 0x40, sizeof(swapper_tsb));
#ifndef CONFIG_DEBUG_PAGEALLOC
        memset(swapper_4m_tsb, 0x40, sizeof(swapper_4m_tsb));
#endif

        if (tlb_type == hypervisor)
                sun4v_pgprot_init();
        else
                sun4u_pgprot_init();

        if (tlb_type == cheetah_plus ||
            tlb_type == hypervisor)
                tsb_phys_patch();

        if (tlb_type == hypervisor) {
                sun4v_patch_tlb_handlers();
                sun4v_ktsb_init();
        }

        /* Find available physical memory... */
        read_obp_memory("available", &pavail[0], &pavail_ents);

        phys_base = 0xffffffffffffffffUL;
        for (i = 0; i < pavail_ents; i++)
                phys_base = min(phys_base, pavail[i].phys_addr);

        set_bit(0, mmu_context_bmap);

        shift = kern_base + PAGE_OFFSET - ((unsigned long)KERNBASE);

        real_end = (unsigned long)_end;
        if ((real_end > ((unsigned long)KERNBASE + 0x400000)))
                bigkernel = 1;
        if ((real_end > ((unsigned long)KERNBASE + 0x800000))) {
                prom_printf("paging_init: Kernel > 8MB, too large.\n");
                prom_halt();
        }

        /* Set kernel pgd to upper alias so physical page computations
         * work.
         */
        init_mm.pgd += ((shift) / (sizeof(pgd_t)));
        
        memset(swapper_low_pmd_dir, 0, sizeof(swapper_low_pmd_dir));

        /* Now can init the kernel/bad page tables. */
        pud_set(pud_offset(&swapper_pg_dir[0], 0),
                swapper_low_pmd_dir + (shift / sizeof(pgd_t)));
        
        inherit_prom_mappings();
        
        /* Ok, we can use our TLB miss and window trap handlers safely.  */
        setup_tba();

        __flush_tlb_all();

        if (tlb_type == hypervisor)
                sun4v_ktsb_register();

        /* Setup bootmem... */
        pages_avail = 0;
        last_valid_pfn = end_pfn = bootmem_init(&pages_avail, phys_base);

        max_mapnr = last_valid_pfn;

        kernel_physical_mapping_init();

        prom_build_devicetree();

        {
                unsigned long zones_size[MAX_NR_ZONES];
                unsigned long zholes_size[MAX_NR_ZONES];
                int znum;

                for (znum = 0; znum < MAX_NR_ZONES; znum++)
                        zones_size[znum] = zholes_size[znum] = 0;

                zones_size[ZONE_NORMAL] = end_pfn;
                zholes_size[ZONE_NORMAL] = end_pfn - pages_avail;

                free_area_init_node(0, &contig_page_data, zones_size,
                                    __pa(PAGE_OFFSET) >> PAGE_SHIFT,
                                    zholes_size);
        }

        device_scan();
}

static void __init taint_real_pages(void)
{
        int i;

        read_obp_memory("available", &pavail_rescan[0], &pavail_rescan_ents);

        /* Find changes discovered in the physmem available rescan and
         * reserve the lost portions in the bootmem maps.
         */
        for (i = 0; i < pavail_ents; i++) {
                unsigned long old_start, old_end;

                old_start = pavail[i].phys_addr;
                old_end = old_start +
                        pavail[i].reg_size;
                while (old_start < old_end) {
                        int n;

                        for (n = 0; n < pavail_rescan_ents; n++) {
                                unsigned long new_start, new_end;

                                new_start = pavail_rescan[n].phys_addr;
                                new_end = new_start +
                                        pavail_rescan[n].reg_size;

                                if (new_start <= old_start &&
                                    new_end >= (old_start + PAGE_SIZE)) {
                                        set_bit(old_start >> 22,
                                                sparc64_valid_addr_bitmap);
                                        goto do_next_page;
                                }
                        }
                        reserve_bootmem(old_start, PAGE_SIZE);

                do_next_page:
                        old_start += PAGE_SIZE;
                }
        }
}

int __init page_in_phys_avail(unsigned long paddr)
{
        int i;

        paddr &= PAGE_MASK;

        for (i = 0; i < pavail_rescan_ents; i++) {
                unsigned long start, end;

                start = pavail_rescan[i].phys_addr;
                end = start + pavail_rescan[i].reg_size;

                if (paddr >= start && paddr < end)
                        return 1;
        }
        if (paddr >= kern_base && paddr < (kern_base + kern_size))
                return 1;
#ifdef CONFIG_BLK_DEV_INITRD
        if (paddr >= __pa(initrd_start) &&
            paddr < __pa(PAGE_ALIGN(initrd_end)))
                return 1;
#endif

        return 0;
}

void __init mem_init(void)
{
        unsigned long codepages, datapages, initpages;
        unsigned long addr, last;
        int i;

        i = last_valid_pfn >> ((22 - PAGE_SHIFT) + 6);
        i += 1;
        sparc64_valid_addr_bitmap = (unsigned long *) alloc_bootmem(i << 3);
        if (sparc64_valid_addr_bitmap == NULL) {
                prom_printf("mem_init: Cannot alloc valid_addr_bitmap.\n");
                prom_halt();
        }
        memset(sparc64_valid_addr_bitmap, 0, i << 3);

        addr = PAGE_OFFSET + kern_base;
        last = PAGE_ALIGN(kern_size) + addr;
        while (addr < last) {
                set_bit(__pa(addr) >> 22, sparc64_valid_addr_bitmap);
                addr += PAGE_SIZE;
        }

        taint_real_pages();

        high_memory = __va(last_valid_pfn << PAGE_SHIFT);

#ifdef CONFIG_DEBUG_BOOTMEM
        prom_printf("mem_init: Calling free_all_bootmem().\n");
#endif
        totalram_pages = num_physpages = free_all_bootmem() - 1;

        /*
         * Set up the zero page, mark it reserved, so that page count
         * is not manipulated when freeing the page from user ptes.
         */
        mem_map_zero = alloc_pages(GFP_KERNEL|__GFP_ZERO, 0);
        if (mem_map_zero == NULL) {
                prom_printf("paging_init: Cannot alloc zero page.\n");
                prom_halt();
        }
        SetPageReserved(mem_map_zero);

        codepages = (((unsigned long) _etext) - ((unsigned long) _start));
        codepages = PAGE_ALIGN(codepages) >> PAGE_SHIFT;
        datapages = (((unsigned long) _edata) - ((unsigned long) _etext));
        datapages = PAGE_ALIGN(datapages) >> PAGE_SHIFT;
        initpages = (((unsigned long) __init_end) - ((unsigned long) __init_begin));
        initpages = PAGE_ALIGN(initpages) >> PAGE_SHIFT;

        printk("Memory: %luk available (%ldk kernel code, %ldk data, %ldk init) [%016lx,%016lx]\n",
               nr_free_pages() << (PAGE_SHIFT-10),
               codepages << (PAGE_SHIFT-10),
               datapages << (PAGE_SHIFT-10), 
               initpages << (PAGE_SHIFT-10), 
               PAGE_OFFSET, (last_valid_pfn << PAGE_SHIFT));

        if (tlb_type == cheetah || tlb_type == cheetah_plus)
                cheetah_ecache_flush_init();
}

void free_initmem(void)
{
        unsigned long addr, initend;

        /*
         * The init section is aligned to 8k in vmlinux.lds. Page align for >8k pagesizes.
         */
        addr = PAGE_ALIGN((unsigned long)(__init_begin));
        initend = (unsigned long)(__init_end) & PAGE_MASK;
        for (; addr < initend; addr += PAGE_SIZE) {
                unsigned long page;
                struct page *p;

                page = (addr +
                        ((unsigned long) __va(kern_base)) -
                        ((unsigned long) KERNBASE));
                memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
                p = virt_to_page(page);

                ClearPageReserved(p);
                init_page_count(p);
                __free_page(p);
                num_physpages++;
                totalram_pages++;
        }
}

#ifdef CONFIG_BLK_DEV_INITRD
void free_initrd_mem(unsigned long start, unsigned long end)
{
        if (start < end)
                printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
        for (; start < end; start += PAGE_SIZE) {
                struct page *p = virt_to_page(start);

                ClearPageReserved(p);
                init_page_count(p);
                __free_page(p);
                num_physpages++;
                totalram_pages++;
        }
}
#endif

#define _PAGE_CACHE_4U  (_PAGE_CP_4U | _PAGE_CV_4U)
#define _PAGE_CACHE_4V  (_PAGE_CP_4V | _PAGE_CV_4V)
#define __DIRTY_BITS_4U  (_PAGE_MODIFIED_4U | _PAGE_WRITE_4U | _PAGE_W_4U)
#define __DIRTY_BITS_4V  (_PAGE_MODIFIED_4V | _PAGE_WRITE_4V | _PAGE_W_4V)
#define __ACCESS_BITS_4U (_PAGE_ACCESSED_4U | _PAGE_READ_4U | _PAGE_R)
#define __ACCESS_BITS_4V (_PAGE_ACCESSED_4V | _PAGE_READ_4V | _PAGE_R)

pgprot_t PAGE_KERNEL __read_mostly;
EXPORT_SYMBOL(PAGE_KERNEL);

pgprot_t PAGE_KERNEL_LOCKED __read_mostly;
pgprot_t PAGE_COPY __read_mostly;

pgprot_t PAGE_SHARED __read_mostly;
EXPORT_SYMBOL(PAGE_SHARED);

pgprot_t PAGE_EXEC __read_mostly;
unsigned long pg_iobits __read_mostly;

unsigned long _PAGE_IE __read_mostly;
EXPORT_SYMBOL(_PAGE_IE);

unsigned long _PAGE_E __read_mostly;
EXPORT_SYMBOL(_PAGE_E);

unsigned long _PAGE_CACHE __read_mostly;
EXPORT_SYMBOL(_PAGE_CACHE);

static void prot_init_common(unsigned long page_none,
                             unsigned long page_shared,
                             unsigned long page_copy,
                             unsigned long page_readonly,
                             unsigned long page_exec_bit)
{
        PAGE_COPY = __pgprot(page_copy);
        PAGE_SHARED = __pgprot(page_shared);

        protection_map[0x0] = __pgprot(page_none);
        protection_map[0x1] = __pgprot(page_readonly & ~page_exec_bit);
        protection_map[0x2] = __pgprot(page_copy & ~page_exec_bit);
        protection_map[0x3] = __pgprot(page_copy & ~page_exec_bit);
        protection_map[0x4] = __pgprot(page_readonly);
        protection_map[0x5] = __pgprot(page_readonly);
        protection_map[0x6] = __pgprot(page_copy);
        protection_map[0x7] = __pgprot(page_copy);
        protection_map[0x8] = __pgprot(page_none);
        protection_map[0x9] = __pgprot(page_readonly & ~page_exec_bit);
        protection_map[0xa] = __pgprot(page_shared & ~page_exec_bit);
        protection_map[0xb] = __pgprot(page_shared & ~page_exec_bit);
        protection_map[0xc] = __pgprot(page_readonly);
        protection_map[0xd] = __pgprot(page_readonly);
        protection_map[0xe] = __pgprot(page_shared);
        protection_map[0xf] = __pgprot(page_shared);
}

static void __init sun4u_pgprot_init(void)
{
        unsigned long page_none, page_shared, page_copy, page_readonly;
        unsigned long page_exec_bit;

        PAGE_KERNEL = __pgprot (_PAGE_PRESENT_4U | _PAGE_VALID |
                                _PAGE_CACHE_4U | _PAGE_P_4U |
                                __ACCESS_BITS_4U | __DIRTY_BITS_4U |
                                _PAGE_EXEC_4U);
        PAGE_KERNEL_LOCKED = __pgprot (_PAGE_PRESENT_4U | _PAGE_VALID |
                                       _PAGE_CACHE_4U | _PAGE_P_4U |
                                       __ACCESS_BITS_4U | __DIRTY_BITS_4U |
                                       _PAGE_EXEC_4U | _PAGE_L_4U);
        PAGE_EXEC = __pgprot(_PAGE_EXEC_4U);

        _PAGE_IE = _PAGE_IE_4U;
        _PAGE_E = _PAGE_E_4U;
        _PAGE_CACHE = _PAGE_CACHE_4U;

        pg_iobits = (_PAGE_VALID | _PAGE_PRESENT_4U | __DIRTY_BITS_4U |
                     __ACCESS_BITS_4U | _PAGE_E_4U);

#ifdef CONFIG_DEBUG_PAGEALLOC
        kern_linear_pte_xor[0] = (_PAGE_VALID | _PAGE_SZBITS_4U) ^
                0xfffff80000000000;
#else
        kern_linear_pte_xor[0] = (_PAGE_VALID | _PAGE_SZ4MB_4U) ^
                0xfffff80000000000;
#endif
        kern_linear_pte_xor[0] |= (_PAGE_CP_4U | _PAGE_CV_4U |
                                   _PAGE_P_4U | _PAGE_W_4U);

        /* XXX Should use 256MB on Panther. XXX */
        kern_linear_pte_xor[1] = kern_linear_pte_xor[0];

        _PAGE_SZBITS = _PAGE_SZBITS_4U;
        _PAGE_ALL_SZ_BITS =  (_PAGE_SZ4MB_4U | _PAGE_SZ512K_4U |
                              _PAGE_SZ64K_4U | _PAGE_SZ8K_4U |
                              _PAGE_SZ32MB_4U | _PAGE_SZ256MB_4U);


        page_none = _PAGE_PRESENT_4U | _PAGE_ACCESSED_4U | _PAGE_CACHE_4U;
        page_shared = (_PAGE_VALID | _PAGE_PRESENT_4U | _PAGE_CACHE_4U |
                       __ACCESS_BITS_4U | _PAGE_WRITE_4U | _PAGE_EXEC_4U);
        page_copy   = (_PAGE_VALID | _PAGE_PRESENT_4U | _PAGE_CACHE_4U |
                       __ACCESS_BITS_4U | _PAGE_EXEC_4U);
        page_readonly   = (_PAGE_VALID | _PAGE_PRESENT_4U | _PAGE_CACHE_4U |
                           __ACCESS_BITS_4U | _PAGE_EXEC_4U);

        page_exec_bit = _PAGE_EXEC_4U;

        prot_init_common(page_none, page_shared, page_copy, page_readonly,
                         page_exec_bit);
}

static void __init sun4v_pgprot_init(void)
{
        unsigned long page_none, page_shared, page_copy, page_readonly;
        unsigned long page_exec_bit;

        PAGE_KERNEL = __pgprot (_PAGE_PRESENT_4V | _PAGE_VALID |
                                _PAGE_CACHE_4V | _PAGE_P_4V |
                                __ACCESS_BITS_4V | __DIRTY_BITS_4V |
                                _PAGE_EXEC_4V);
        PAGE_KERNEL_LOCKED = PAGE_KERNEL;
        PAGE_EXEC = __pgprot(_PAGE_EXEC_4V);

        _PAGE_IE = _PAGE_IE_4V;
        _PAGE_E = _PAGE_E_4V;
        _PAGE_CACHE = _PAGE_CACHE_4V;

#ifdef CONFIG_DEBUG_PAGEALLOC
        kern_linear_pte_xor[0] = (_PAGE_VALID | _PAGE_SZBITS_4V) ^
                0xfffff80000000000;
#else
        kern_linear_pte_xor[0] = (_PAGE_VALID | _PAGE_SZ4MB_4V) ^
                0xfffff80000000000;
#endif
        kern_linear_pte_xor[0] |= (_PAGE_CP_4V | _PAGE_CV_4V |
                                   _PAGE_P_4V | _PAGE_W_4V);

#ifdef CONFIG_DEBUG_PAGEALLOC
        kern_linear_pte_xor[1] = (_PAGE_VALID | _PAGE_SZBITS_4V) ^
                0xfffff80000000000;
#else
        kern_linear_pte_xor[1] = (_PAGE_VALID | _PAGE_SZ256MB_4V) ^
                0xfffff80000000000;
#endif
        kern_linear_pte_xor[1] |= (_PAGE_CP_4V | _PAGE_CV_4V |
                                   _PAGE_P_4V | _PAGE_W_4V);

        pg_iobits = (_PAGE_VALID | _PAGE_PRESENT_4V | __DIRTY_BITS_4V |
                     __ACCESS_BITS_4V | _PAGE_E_4V);

        _PAGE_SZBITS = _PAGE_SZBITS_4V;
        _PAGE_ALL_SZ_BITS = (_PAGE_SZ16GB_4V | _PAGE_SZ2GB_4V |
                             _PAGE_SZ256MB_4V | _PAGE_SZ32MB_4V |
                             _PAGE_SZ4MB_4V | _PAGE_SZ512K_4V |
                             _PAGE_SZ64K_4V | _PAGE_SZ8K_4V);

        page_none = _PAGE_PRESENT_4V | _PAGE_ACCESSED_4V | _PAGE_CACHE_4V;
        page_shared = (_PAGE_VALID | _PAGE_PRESENT_4V | _PAGE_CACHE_4V |
                       __ACCESS_BITS_4V | _PAGE_WRITE_4V | _PAGE_EXEC_4V);
        page_copy   = (_PAGE_VALID | _PAGE_PRESENT_4V | _PAGE_CACHE_4V |
                       __ACCESS_BITS_4V | _PAGE_EXEC_4V);
        page_readonly = (_PAGE_VALID | _PAGE_PRESENT_4V | _PAGE_CACHE_4V |
                         __ACCESS_BITS_4V | _PAGE_EXEC_4V);

        page_exec_bit = _PAGE_EXEC_4V;

        prot_init_common(page_none, page_shared, page_copy, page_readonly,
                         page_exec_bit);
}

unsigned long pte_sz_bits(unsigned long sz)
{
        if (tlb_type == hypervisor) {
                switch (sz) {
                case 8 * 1024:
                default:
                        return _PAGE_SZ8K_4V;
                case 64 * 1024:
                        return _PAGE_SZ64K_4V;
                case 512 * 1024:
                        return _PAGE_SZ512K_4V;
                case 4 * 1024 * 1024:
                        return _PAGE_SZ4MB_4V;
                };
        } else {
                switch (sz) {
                case 8 * 1024:
                default:
                        return _PAGE_SZ8K_4U;
                case 64 * 1024:
                        return _PAGE_SZ64K_4U;
                case 512 * 1024:
                        return _PAGE_SZ512K_4U;
                case 4 * 1024 * 1024:
                        return _PAGE_SZ4MB_4U;
                };
        }
}

pte_t mk_pte_io(unsigned long page, pgprot_t prot, int space, unsigned long page_size)
{
        pte_t pte;

        pte_val(pte)  = page | pgprot_val(pgprot_noncached(prot));
        pte_val(pte) |= (((unsigned long)space) << 32);
        pte_val(pte) |= pte_sz_bits(page_size);

        return pte;
}

static unsigned long kern_large_tte(unsigned long paddr)
{
        unsigned long val;

        val = (_PAGE_VALID | _PAGE_SZ4MB_4U |
               _PAGE_CP_4U | _PAGE_CV_4U | _PAGE_P_4U |
               _PAGE_EXEC_4U | _PAGE_L_4U | _PAGE_W_4U);
        if (tlb_type == hypervisor)
                val = (_PAGE_VALID | _PAGE_SZ4MB_4V |
                       _PAGE_CP_4V | _PAGE_CV_4V | _PAGE_P_4V |
                       _PAGE_EXEC_4V | _PAGE_W_4V);

        return val | paddr;
}

/* If not locked, zap it. */
void __flush_tlb_all(void)
{
        unsigned long pstate;
        int i;

        __asm__ __volatile__("flushw\n\t"
                             "rdpr      %%pstate, %0\n\t"
                             "wrpr      %0, %1, %%pstate"
                             : "=r" (pstate)
                             : "i" (PSTATE_IE));
        if (tlb_type == spitfire) {
                for (i = 0; i < 64; i++) {
                        /* Spitfire Errata #32 workaround */
                        /* NOTE: Always runs on spitfire, so no
                         *       cheetah+ page size encodings.
                         */
                        __asm__ __volatile__("stxa      %0, [%1] %2\n\t"
                                             "flush     %%g6"
                                             : /* No outputs */
                                             : "r" (0),
                                             "r" (PRIMARY_CONTEXT), "i" (ASI_DMMU));

                        if (!(spitfire_get_dtlb_data(i) & _PAGE_L_4U)) {
                                __asm__ __volatile__("stxa %%g0, [%0] %1\n\t"
                                                     "membar #Sync"
                                                     : /* no outputs */
                                                     : "r" (TLB_TAG_ACCESS), "i" (ASI_DMMU));
                                spitfire_put_dtlb_data(i, 0x0UL);
                        }

                        /* Spitfire Errata #32 workaround */
                        /* NOTE: Always runs on spitfire, so no
                         *       cheetah+ page size encodings.
                         */
                        __asm__ __volatile__("stxa      %0, [%1] %2\n\t"
                                             "flush     %%g6"
                                             : /* No outputs */
                                             : "r" (0),
                                             "r" (PRIMARY_CONTEXT), "i" (ASI_DMMU));

                        if (!(spitfire_get_itlb_data(i) & _PAGE_L_4U)) {
                                __asm__ __volatile__("stxa %%g0, [%0] %1\n\t"
                                                     "membar #Sync"
                                                     : /* no outputs */
                                                     : "r" (TLB_TAG_ACCESS), "i" (ASI_IMMU));
                                spitfire_put_itlb_data(i, 0x0UL);
                        }
                }
        } else if (tlb_type == cheetah || tlb_type == cheetah_plus) {
                cheetah_flush_dtlb_all();
                cheetah_flush_itlb_all();
        }
        __asm__ __volatile__("wrpr      %0, 0, %%pstate"
                             : : "r" (pstate));
}

#ifdef CONFIG_MEMORY_HOTPLUG

void online_page(struct page *page)
{
        ClearPageReserved(page);
        init_page_count(page);
        __free_page(page);
        totalram_pages++;
        num_physpages++;
}

int remove_memory(u64 start, u64 size)
{
        return -EINVAL;
}

#endif /* CONFIG_MEMORY_HOTPLUG */