init.c

Go to the documentation of this file.

/*
 * Initialize MMU support.
 *
 * Copyright (C) 1998-2003 Hewlett-Packard Co
 *  David Mosberger-Tang <[email protected]>
 */
#include <linux/kernel.h>
#include <linux/init.h>

#include <linux/bootmem.h>
#include <linux/efi.h>
#include <linux/elf.h>
#include <linux/memblock.h>
#include <linux/mm.h>
#include <linux/mmzone.h>
#include <linux/module.h>
#include <linux/personality.h>
#include <linux/reboot.h>
#include <linux/slab.h>
#include <linux/swap.h>
#include <linux/proc_fs.h>
#include <linux/bitops.h>
#include <linux/kexec.h>

#include <asm/dma.h>
#include <asm/io.h>
#include <asm/machvec.h>
#include <asm/numa.h>
#include <asm/patch.h>
#include <asm/pgalloc.h>
#include <asm/sal.h>
#include <asm/sections.h>
#include <asm/tlb.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
#include <asm/mca.h>
#include <asm/paravirt.h>

extern void ia64_tlb_init (void);

unsigned long MAX_DMA_ADDRESS = PAGE_OFFSET + 0x100000000UL;

#ifdef CONFIG_VIRTUAL_MEM_MAP
unsigned long VMALLOC_END = VMALLOC_END_INIT;
EXPORT_SYMBOL(VMALLOC_END);
struct page *vmem_map;
EXPORT_SYMBOL(vmem_map);
#endif

struct page *zero_page_memmap_ptr;  /* map entry for zero page */
EXPORT_SYMBOL(zero_page_memmap_ptr);

void
__ia64_sync_icache_dcache (pte_t pte)
{
    unsigned long addr;
    struct page *page;

    page = pte_page(pte);
    addr = (unsigned long) page_address(page);

    if (test_bit(PG_arch_1, &page->flags))
        return;             /* i-cache is already coherent with d-cache */

    flush_icache_range(addr, addr + (PAGE_SIZE << compound_order(page)));
    set_bit(PG_arch_1, &page->flags);   /* mark page as clean */
}

/*
 * Since DMA is i-cache coherent, any (complete) pages that were written via
 * DMA can be marked as "clean" so that lazy_mmu_prot_update() doesn't have to
 * flush them when they get mapped into an executable vm-area.
 */
void
dma_mark_clean(void *addr, size_t size)
{
    unsigned long pg_addr, end;

    pg_addr = PAGE_ALIGN((unsigned long) addr);
    end = (unsigned long) addr + size;
    while (pg_addr + PAGE_SIZE <= end) {
        struct page *page = virt_to_page(pg_addr);
        set_bit(PG_arch_1, &page->flags);
        pg_addr += PAGE_SIZE;
    }
}

inline void
ia64_set_rbs_bot (void)
{
    unsigned long stack_size = rlimit_max(RLIMIT_STACK) & -16;

    if (stack_size > MAX_USER_STACK_SIZE)
        stack_size = MAX_USER_STACK_SIZE;
    current->thread.rbs_bot = PAGE_ALIGN(current->mm->start_stack - stack_size);
}

/*
 * This performs some platform-dependent address space initialization.
 * On IA-64, we want to setup the VM area for the register backing
 * store (which grows upwards) and install the gateway page which is
 * used for signal trampolines, etc.
 */
void
ia64_init_addr_space (void)
{
    struct vm_area_struct *vma;

    ia64_set_rbs_bot();

    /*
     * If we're out of memory and kmem_cache_alloc() returns NULL, we simply ignore
     * the problem.  When the process attempts to write to the register backing store
     * for the first time, it will get a SEGFAULT in this case.
     */
    vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
    if (vma) {
        INIT_LIST_HEAD(&vma->anon_vma_chain);
        vma->vm_mm = current->mm;
        vma->vm_start = current->thread.rbs_bot & PAGE_MASK;
        vma->vm_end = vma->vm_start + PAGE_SIZE;
        vma->vm_flags = VM_DATA_DEFAULT_FLAGS|VM_GROWSUP|VM_ACCOUNT;
        vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
        down_write(&current->mm->mmap_sem);
        if (insert_vm_struct(current->mm, vma)) {
            up_write(&current->mm->mmap_sem);
            kmem_cache_free(vm_area_cachep, vma);
            return;
        }
        up_write(&current->mm->mmap_sem);
    }

    /* map NaT-page at address zero to speed up speculative dereferencing of NULL: */
    if (!(current->personality & MMAP_PAGE_ZERO)) {
        vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
        if (vma) {
            INIT_LIST_HEAD(&vma->anon_vma_chain);
            vma->vm_mm = current->mm;
            vma->vm_end = PAGE_SIZE;
            vma->vm_page_prot = __pgprot(pgprot_val(PAGE_READONLY) | _PAGE_MA_NAT);
            vma->vm_flags = VM_READ | VM_MAYREAD | VM_IO |
                    VM_DONTEXPAND | VM_DONTDUMP;
            down_write(&current->mm->mmap_sem);
            if (insert_vm_struct(current->mm, vma)) {
                up_write(&current->mm->mmap_sem);
                kmem_cache_free(vm_area_cachep, vma);
                return;
            }
            up_write(&current->mm->mmap_sem);
        }
    }
}

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

    addr = (unsigned long) ia64_imva(__init_begin);
    eaddr = (unsigned long) ia64_imva(__init_end);
    while (addr < eaddr) {
        ClearPageReserved(virt_to_page(addr));
        init_page_count(virt_to_page(addr));
        free_page(addr);
        ++totalram_pages;
        addr += PAGE_SIZE;
    }
    printk(KERN_INFO "Freeing unused kernel memory: %ldkB freed\n",
           (__init_end - __init_begin) >> 10);
}

void __init
free_initrd_mem (unsigned long start, unsigned long end)
{
    struct page *page;
    /*
     * EFI uses 4KB pages while the kernel can use 4KB or bigger.
     * Thus EFI and the kernel may have different page sizes. It is
     * therefore possible to have the initrd share the same page as
     * the end of the kernel (given current setup).
     *
     * To avoid freeing/using the wrong page (kernel sized) we:
     *  - align up the beginning of initrd
     *  - align down the end of initrd
     *
     *  |             |
     *  |=============| a000
     *  |             |
     *  |             |
     *  |             | 9000
     *  |/////////////|
     *  |/////////////|
     *  |=============| 8000
     *  |///INITRD////|
     *  |/////////////|
     *  |/////////////| 7000
     *  |             |
     *  |KKKKKKKKKKKKK|
     *  |=============| 6000
     *  |KKKKKKKKKKKKK|
     *  |KKKKKKKKKKKKK|
     *  K=kernel using 8KB pages
     *
     * In this example, we must free page 8000 ONLY. So we must align up
     * initrd_start and keep initrd_end as is.
     */
    start = PAGE_ALIGN(start);
    end = end & PAGE_MASK;

    if (start < end)
        printk(KERN_INFO "Freeing initrd memory: %ldkB freed\n", (end - start) >> 10);

    for (; start < end; start += PAGE_SIZE) {
        if (!virt_addr_valid(start))
            continue;
        page = virt_to_page(start);
        ClearPageReserved(page);
        init_page_count(page);
        free_page(start);
        ++totalram_pages;
    }
}

/*
 * This installs a clean page in the kernel's page table.
 */
static struct page * __init
put_kernel_page (struct page *page, unsigned long address, pgprot_t pgprot)
{
    pgd_t *pgd;
    pud_t *pud;
    pmd_t *pmd;
    pte_t *pte;

    if (!PageReserved(page))
        printk(KERN_ERR "put_kernel_page: page at 0x%p not in reserved memory\n",
               page_address(page));

    pgd = pgd_offset_k(address);        /* note: this is NOT pgd_offset()! */

    {
        pud = pud_alloc(&init_mm, pgd, address);
        if (!pud)
            goto out;
        pmd = pmd_alloc(&init_mm, pud, address);
        if (!pmd)
            goto out;
        pte = pte_alloc_kernel(pmd, address);
        if (!pte)
            goto out;
        if (!pte_none(*pte))
            goto out;
        set_pte(pte, mk_pte(page, pgprot));
    }
  out:
    /* no need for flush_tlb */
    return page;
}

static void __init
setup_gate (void)
{
    void *gate_section;
    struct page *page;

    /*
     * Map the gate page twice: once read-only to export the ELF
     * headers etc. and once execute-only page to enable
     * privilege-promotion via "epc":
     */
    gate_section = paravirt_get_gate_section();
    page = virt_to_page(ia64_imva(gate_section));
    put_kernel_page(page, GATE_ADDR, PAGE_READONLY);
#ifdef HAVE_BUGGY_SEGREL
    page = virt_to_page(ia64_imva(gate_section + PAGE_SIZE));
    put_kernel_page(page, GATE_ADDR + PAGE_SIZE, PAGE_GATE);
#else
    put_kernel_page(page, GATE_ADDR + PERCPU_PAGE_SIZE, PAGE_GATE);
    /* Fill in the holes (if any) with read-only zero pages: */
    {
        unsigned long addr;

        for (addr = GATE_ADDR + PAGE_SIZE;
             addr < GATE_ADDR + PERCPU_PAGE_SIZE;
             addr += PAGE_SIZE)
        {
            put_kernel_page(ZERO_PAGE(0), addr,
                    PAGE_READONLY);
            put_kernel_page(ZERO_PAGE(0), addr + PERCPU_PAGE_SIZE,
                    PAGE_READONLY);
        }
    }
#endif
    ia64_patch_gate();
}

void __devinit
ia64_mmu_init (void *my_cpu_data)
{
    unsigned long pta, impl_va_bits;
    extern void __devinit tlb_init (void);

#ifdef CONFIG_DISABLE_VHPT
#   define VHPT_ENABLE_BIT  0
#else
#   define VHPT_ENABLE_BIT  1
#endif

    /*
     * Check if the virtually mapped linear page table (VMLPT) overlaps with a mapped
     * address space.  The IA-64 architecture guarantees that at least 50 bits of
     * virtual address space are implemented but if we pick a large enough page size
     * (e.g., 64KB), the mapped address space is big enough that it will overlap with
     * VMLPT.  I assume that once we run on machines big enough to warrant 64KB pages,
     * IMPL_VA_MSB will be significantly bigger, so this is unlikely to become a
     * problem in practice.  Alternatively, we could truncate the top of the mapped
     * address space to not permit mappings that would overlap with the VMLPT.
     * --davidm 00/12/06
     */
#   define pte_bits         3
#   define mapped_space_bits    (3*(PAGE_SHIFT - pte_bits) + PAGE_SHIFT)
    /*
     * The virtual page table has to cover the entire implemented address space within
     * a region even though not all of this space may be mappable.  The reason for
     * this is that the Access bit and Dirty bit fault handlers perform
     * non-speculative accesses to the virtual page table, so the address range of the
     * virtual page table itself needs to be covered by virtual page table.
     */
#   define vmlpt_bits       (impl_va_bits - PAGE_SHIFT + pte_bits)
#   define POW2(n)          (1ULL << (n))

    impl_va_bits = ffz(~(local_cpu_data->unimpl_va_mask | (7UL << 61)));

    if (impl_va_bits < 51 || impl_va_bits > 61)
        panic("CPU has bogus IMPL_VA_MSB value of %lu!\n", impl_va_bits - 1);
    /*
     * mapped_space_bits - PAGE_SHIFT is the total number of ptes we need,
     * which must fit into "vmlpt_bits - pte_bits" slots. Second half of
     * the test makes sure that our mapped space doesn't overlap the
     * unimplemented hole in the middle of the region.
     */
    if ((mapped_space_bits - PAGE_SHIFT > vmlpt_bits - pte_bits) ||
        (mapped_space_bits > impl_va_bits - 1))
        panic("Cannot build a big enough virtual-linear page table"
              " to cover mapped address space.\n"
              " Try using a smaller page size.\n");


    /* place the VMLPT at the end of each page-table mapped region: */
    pta = POW2(61) - POW2(vmlpt_bits);

    /*
     * Set the (virtually mapped linear) page table address.  Bit
     * 8 selects between the short and long format, bits 2-7 the
     * size of the table, and bit 0 whether the VHPT walker is
     * enabled.
     */
    ia64_set_pta(pta | (0 << 8) | (vmlpt_bits << 2) | VHPT_ENABLE_BIT);

    ia64_tlb_init();

#ifdef  CONFIG_HUGETLB_PAGE
    ia64_set_rr(HPAGE_REGION_BASE, HPAGE_SHIFT << 2);
    ia64_srlz_d();
#endif
}

#ifdef CONFIG_VIRTUAL_MEM_MAP
int vmemmap_find_next_valid_pfn(int node, int i)
{
    unsigned long end_address, hole_next_pfn;
    unsigned long stop_address;
    pg_data_t *pgdat = NODE_DATA(node);

    end_address = (unsigned long) &vmem_map[pgdat->node_start_pfn + i];
    end_address = PAGE_ALIGN(end_address);

    stop_address = (unsigned long) &vmem_map[
        pgdat->node_start_pfn + pgdat->node_spanned_pages];

    do {
        pgd_t *pgd;
        pud_t *pud;
        pmd_t *pmd;
        pte_t *pte;

        pgd = pgd_offset_k(end_address);
        if (pgd_none(*pgd)) {
            end_address += PGDIR_SIZE;
            continue;
        }

        pud = pud_offset(pgd, end_address);
        if (pud_none(*pud)) {
            end_address += PUD_SIZE;
            continue;
        }

        pmd = pmd_offset(pud, end_address);
        if (pmd_none(*pmd)) {
            end_address += PMD_SIZE;
            continue;
        }

        pte = pte_offset_kernel(pmd, end_address);
retry_pte:
        if (pte_none(*pte)) {
            end_address += PAGE_SIZE;
            pte++;
            if ((end_address < stop_address) &&
                (end_address != ALIGN(end_address, 1UL << PMD_SHIFT)))
                goto retry_pte;
            continue;
        }
        /* Found next valid vmem_map page */
        break;
    } while (end_address < stop_address);

    end_address = min(end_address, stop_address);
    end_address = end_address - (unsigned long) vmem_map + sizeof(struct page) - 1;
    hole_next_pfn = end_address / sizeof(struct page);
    return hole_next_pfn - pgdat->node_start_pfn;
}

int __init create_mem_map_page_table(u64 start, u64 end, void *arg)
{
    unsigned long address, start_page, end_page;
    struct page *map_start, *map_end;
    int node;
    pgd_t *pgd;
    pud_t *pud;
    pmd_t *pmd;
    pte_t *pte;

    map_start = vmem_map + (__pa(start) >> PAGE_SHIFT);
    map_end   = vmem_map + (__pa(end) >> PAGE_SHIFT);

    start_page = (unsigned long) map_start & PAGE_MASK;
    end_page = PAGE_ALIGN((unsigned long) map_end);
    node = paddr_to_nid(__pa(start));

    for (address = start_page; address < end_page; address += PAGE_SIZE) {
        pgd = pgd_offset_k(address);
        if (pgd_none(*pgd))
            pgd_populate(&init_mm, pgd, alloc_bootmem_pages_node(NODE_DATA(node), PAGE_SIZE));
        pud = pud_offset(pgd, address);

        if (pud_none(*pud))
            pud_populate(&init_mm, pud, alloc_bootmem_pages_node(NODE_DATA(node), PAGE_SIZE));
        pmd = pmd_offset(pud, address);

        if (pmd_none(*pmd))
            pmd_populate_kernel(&init_mm, pmd, alloc_bootmem_pages_node(NODE_DATA(node), PAGE_SIZE));
        pte = pte_offset_kernel(pmd, address);

        if (pte_none(*pte))
            set_pte(pte, pfn_pte(__pa(alloc_bootmem_pages_node(NODE_DATA(node), PAGE_SIZE)) >> PAGE_SHIFT,
                         PAGE_KERNEL));
    }
    return 0;
}

struct memmap_init_callback_data {
    struct page *start;
    struct page *end;
    int nid;
    unsigned long zone;
};

static int __meminit
virtual_memmap_init(u64 start, u64 end, void *arg)
{
    struct memmap_init_callback_data *args;
    struct page *map_start, *map_end;

    args = (struct memmap_init_callback_data *) arg;
    map_start = vmem_map + (__pa(start) >> PAGE_SHIFT);
    map_end   = vmem_map + (__pa(end) >> PAGE_SHIFT);

    if (map_start < args->start)
        map_start = args->start;
    if (map_end > args->end)
        map_end = args->end;

    /*
     * We have to initialize "out of bounds" struct page elements that fit completely
     * on the same pages that were allocated for the "in bounds" elements because they
     * may be referenced later (and found to be "reserved").
     */
    map_start -= ((unsigned long) map_start & (PAGE_SIZE - 1)) / sizeof(struct page);
    map_end += ((PAGE_ALIGN((unsigned long) map_end) - (unsigned long) map_end)
            / sizeof(struct page));

    if (map_start < map_end)
        memmap_init_zone((unsigned long)(map_end - map_start),
                 args->nid, args->zone, page_to_pfn(map_start),
                 MEMMAP_EARLY);
    return 0;
}

void __meminit
memmap_init (unsigned long size, int nid, unsigned long zone,
         unsigned long start_pfn)
{
    if (!vmem_map)
        memmap_init_zone(size, nid, zone, start_pfn, MEMMAP_EARLY);
    else {
        struct page *start;
        struct memmap_init_callback_data args;

        start = pfn_to_page(start_pfn);
        args.start = start;
        args.end = start + size;
        args.nid = nid;
        args.zone = zone;

        efi_memmap_walk(virtual_memmap_init, &args);
    }
}

int
ia64_pfn_valid (unsigned long pfn)
{
    char byte;
    struct page *pg = pfn_to_page(pfn);

    return     (__get_user(byte, (char __user *) pg) == 0)
        && ((((u64)pg & PAGE_MASK) == (((u64)(pg + 1) - 1) & PAGE_MASK))
            || (__get_user(byte, (char __user *) (pg + 1) - 1) == 0));
}
EXPORT_SYMBOL(ia64_pfn_valid);

int __init find_largest_hole(u64 start, u64 end, void *arg)
{
    u64 *max_gap = arg;

    static u64 last_end = PAGE_OFFSET;

    /* NOTE: this algorithm assumes efi memmap table is ordered */

    if (*max_gap < (start - last_end))
        *max_gap = start - last_end;
    last_end = end;
    return 0;
}

#endif /* CONFIG_VIRTUAL_MEM_MAP */

int __init register_active_ranges(u64 start, u64 len, int nid)
{
    u64 end = start + len;

#ifdef CONFIG_KEXEC
    if (start > crashk_res.start && start < crashk_res.end)
        start = crashk_res.end;
    if (end > crashk_res.start && end < crashk_res.end)
        end = crashk_res.start;
#endif

    if (start < end)
        memblock_add_node(__pa(start), end - start, nid);
    return 0;
}

static int __init
count_reserved_pages(u64 start, u64 end, void *arg)
{
    unsigned long num_reserved = 0;
    unsigned long *count = arg;

    for (; start < end; start += PAGE_SIZE)
        if (PageReserved(virt_to_page(start)))
            ++num_reserved;
    *count += num_reserved;
    return 0;
}

int
find_max_min_low_pfn (u64 start, u64 end, void *arg)
{
    unsigned long pfn_start, pfn_end;
#ifdef CONFIG_FLATMEM
    pfn_start = (PAGE_ALIGN(__pa(start))) >> PAGE_SHIFT;
    pfn_end = (PAGE_ALIGN(__pa(end - 1))) >> PAGE_SHIFT;
#else
    pfn_start = GRANULEROUNDDOWN(__pa(start)) >> PAGE_SHIFT;
    pfn_end = GRANULEROUNDUP(__pa(end - 1)) >> PAGE_SHIFT;
#endif
    min_low_pfn = min(min_low_pfn, pfn_start);
    max_low_pfn = max(max_low_pfn, pfn_end);
    return 0;
}

/*
 * Boot command-line option "nolwsys" can be used to disable the use of any light-weight
 * system call handler.  When this option is in effect, all fsyscalls will end up bubbling
 * down into the kernel and calling the normal (heavy-weight) syscall handler.  This is
 * useful for performance testing, but conceivably could also come in handy for debugging
 * purposes.
 */

static int nolwsys __initdata;

static int __init
nolwsys_setup (char *s)
{
    nolwsys = 1;
    return 1;
}

__setup("nolwsys", nolwsys_setup);

void __init
mem_init (void)
{
    long reserved_pages, codesize, datasize, initsize;
    pg_data_t *pgdat;
    int i;

    BUG_ON(PTRS_PER_PGD * sizeof(pgd_t) != PAGE_SIZE);
    BUG_ON(PTRS_PER_PMD * sizeof(pmd_t) != PAGE_SIZE);
    BUG_ON(PTRS_PER_PTE * sizeof(pte_t) != PAGE_SIZE);

#ifdef CONFIG_PCI
    /*
     * This needs to be called _after_ the command line has been parsed but _before_
     * any drivers that may need the PCI DMA interface are initialized or bootmem has
     * been freed.
     */
    platform_dma_init();
#endif

#ifdef CONFIG_FLATMEM
    BUG_ON(!mem_map);
    max_mapnr = max_low_pfn;
#endif

    high_memory = __va(max_low_pfn * PAGE_SIZE);

    for_each_online_pgdat(pgdat)
        if (pgdat->bdata->node_bootmem_map)
            totalram_pages += free_all_bootmem_node(pgdat);

    reserved_pages = 0;
    efi_memmap_walk(count_reserved_pages, &reserved_pages);

    codesize =  (unsigned long) _etext - (unsigned long) _stext;
    datasize =  (unsigned long) _edata - (unsigned long) _etext;
    initsize =  (unsigned long) __init_end - (unsigned long) __init_begin;

    printk(KERN_INFO "Memory: %luk/%luk available (%luk code, %luk reserved, "
           "%luk data, %luk init)\n", nr_free_pages() << (PAGE_SHIFT - 10),
           num_physpages << (PAGE_SHIFT - 10), codesize >> 10,
           reserved_pages << (PAGE_SHIFT - 10), datasize >> 10, initsize >> 10);


    /*
     * For fsyscall entrpoints with no light-weight handler, use the ordinary
     * (heavy-weight) handler, but mark it by setting bit 0, so the fsyscall entry
     * code can tell them apart.
     */
    for (i = 0; i < NR_syscalls; ++i) {
        extern unsigned long sys_call_table[NR_syscalls];
        unsigned long *fsyscall_table = paravirt_get_fsyscall_table();

        if (!fsyscall_table[i] || nolwsys)
            fsyscall_table[i] = sys_call_table[i] | 1;
    }
    setup_gate();
}

#ifdef CONFIG_MEMORY_HOTPLUG
int arch_add_memory(int nid, u64 start, u64 size)
{
    pg_data_t *pgdat;
    struct zone *zone;
    unsigned long start_pfn = start >> PAGE_SHIFT;
    unsigned long nr_pages = size >> PAGE_SHIFT;
    int ret;

    pgdat = NODE_DATA(nid);

    zone = pgdat->node_zones + ZONE_NORMAL;
    ret = __add_pages(nid, zone, start_pfn, nr_pages);

    if (ret)
        printk("%s: Problem encountered in __add_pages() as ret=%d\n",
               __func__,  ret);

    return ret;
}
#endif

/*
 * Even when CONFIG_IA32_SUPPORT is not enabled it is
 * useful to have the Linux/x86 domain registered to
 * avoid an attempted module load when emulators call
 * personality(PER_LINUX32). This saves several milliseconds
 * on each such call.
 */
static struct exec_domain ia32_exec_domain;

static int __init
per_linux32_init(void)
{
    ia32_exec_domain.name = "Linux/x86";
    ia32_exec_domain.handler = NULL;
    ia32_exec_domain.pers_low = PER_LINUX32;
    ia32_exec_domain.pers_high = PER_LINUX32;
    ia32_exec_domain.signal_map = default_exec_domain.signal_map;
    ia32_exec_domain.signal_invmap = default_exec_domain.signal_invmap;
    register_exec_domain(&ia32_exec_domain);

    return 0;
}

__initcall(per_linux32_init);