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init.c

/*
 * Initialize MMU support.
 *
 * Copyright (C) 1998-2003 Hewlett-Packard Co
 *    David Mosberger-Tang <davidm@hpl.hp.com>
 */
#include <linux/kernel.h>
#include <linux/init.h>

#include <linux/bootmem.h>
#include <linux/efi.h>
#include <linux/elf.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/ia32.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/system.h>
#include <asm/tlb.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
#include <asm/mca.h>
#include <asm/paravirt.h>

DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);

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 = current->signal->rlim[RLIMIT_STACK].rlim_max & -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) {
            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) {
                  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_RESERVED;
                  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)
            add_active_range(nid, __pa(start) >> PAGE_SHIFT,
                  __pa(end) >> PAGE_SHIFT);
      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_IA32_SUPPORT
      ia32_mem_init();
#endif
}

#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);

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