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tlb.c

/*
 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 * Licensed under the GPL
 */

#include "linux/mm.h"
#include "asm/pgtable.h"
#include "asm/tlbflush.h"
#include "as-layout.h"
#include "mem_user.h"
#include "os.h"
#include "skas.h"
#include "tlb.h"

struct host_vm_change {
      struct host_vm_op {
            enum { NONE, MMAP, MUNMAP, MPROTECT } type;
            union {
                  struct {
                        unsigned long addr;
                        unsigned long len;
                        unsigned int prot;
                        int fd;
                        __u64 offset;
                  } mmap;
                  struct {
                        unsigned long addr;
                        unsigned long len;
                  } munmap;
                  struct {
                        unsigned long addr;
                        unsigned long len;
                        unsigned int prot;
                  } mprotect;
            } u;
      } ops[1];
      int index;
      struct mm_id *id;
      void *data;
      int force;
};

#define INIT_HVC(mm, force) \
      ((struct host_vm_change) \
       { .ops           = { { .type = NONE } }, \
         .id            = &mm->context.id, \
               .data    = NULL, \
         .index   = 0, \
         .force   = force })

static int do_ops(struct host_vm_change *hvc, int end,
              int finished)
{
      struct host_vm_op *op;
      int i, ret = 0;

      for (i = 0; i < end && !ret; i++) {
            op = &hvc->ops[i];
            switch(op->type) {
            case MMAP:
                  ret = map(hvc->id, op->u.mmap.addr, op->u.mmap.len,
                          op->u.mmap.prot, op->u.mmap.fd,
                          op->u.mmap.offset, finished, &hvc->data);
                  break;
            case MUNMAP:
                  ret = unmap(hvc->id, op->u.munmap.addr,
                            op->u.munmap.len, finished, &hvc->data);
                  break;
            case MPROTECT:
                  ret = protect(hvc->id, op->u.mprotect.addr,
                              op->u.mprotect.len, op->u.mprotect.prot,
                              finished, &hvc->data);
                  break;
            default:
                  printk(KERN_ERR "Unknown op type %d in do_ops\n",
                         op->type);
                  break;
            }
      }

      return ret;
}

static int add_mmap(unsigned long virt, unsigned long phys, unsigned long len,
                unsigned int prot, struct host_vm_change *hvc)
{
      __u64 offset;
      struct host_vm_op *last;
      int fd, ret = 0;

      fd = phys_mapping(phys, &offset);
      if (hvc->index != 0) {
            last = &hvc->ops[hvc->index - 1];
            if ((last->type == MMAP) &&
               (last->u.mmap.addr + last->u.mmap.len == virt) &&
               (last->u.mmap.prot == prot) && (last->u.mmap.fd == fd) &&
               (last->u.mmap.offset + last->u.mmap.len == offset)) {
                  last->u.mmap.len += len;
                  return 0;
            }
      }

      if (hvc->index == ARRAY_SIZE(hvc->ops)) {
            ret = do_ops(hvc, ARRAY_SIZE(hvc->ops), 0);
            hvc->index = 0;
      }

      hvc->ops[hvc->index++] = ((struct host_vm_op)
                          { .type   = MMAP,
                            .u = { .mmap = { .addr    = virt,
                                         .len   = len,
                                         .prot  = prot,
                                         .fd    = fd,
                                         .offset      = offset }
                     } });
      return ret;
}

static int add_munmap(unsigned long addr, unsigned long len,
                  struct host_vm_change *hvc)
{
      struct host_vm_op *last;
      int ret = 0;

      if (hvc->index != 0) {
            last = &hvc->ops[hvc->index - 1];
            if ((last->type == MUNMAP) &&
               (last->u.munmap.addr + last->u.mmap.len == addr)) {
                  last->u.munmap.len += len;
                  return 0;
            }
      }

      if (hvc->index == ARRAY_SIZE(hvc->ops)) {
            ret = do_ops(hvc, ARRAY_SIZE(hvc->ops), 0);
            hvc->index = 0;
      }

      hvc->ops[hvc->index++] = ((struct host_vm_op)
                          { .type   = MUNMAP,
                            .u = { .munmap = { .addr  = addr,
                                           .len = len } } });
      return ret;
}

static int add_mprotect(unsigned long addr, unsigned long len,
                  unsigned int prot, struct host_vm_change *hvc)
{
      struct host_vm_op *last;
      int ret = 0;

      if (hvc->index != 0) {
            last = &hvc->ops[hvc->index - 1];
            if ((last->type == MPROTECT) &&
               (last->u.mprotect.addr + last->u.mprotect.len == addr) &&
               (last->u.mprotect.prot == prot)) {
                  last->u.mprotect.len += len;
                  return 0;
            }
      }

      if (hvc->index == ARRAY_SIZE(hvc->ops)) {
            ret = do_ops(hvc, ARRAY_SIZE(hvc->ops), 0);
            hvc->index = 0;
      }

      hvc->ops[hvc->index++] = ((struct host_vm_op)
                          { .type   = MPROTECT,
                            .u = { .mprotect = { .addr      = addr,
                                           .len = len,
                                           .prot      = prot } } });
      return ret;
}

#define ADD_ROUND(n, inc) (((n) + (inc)) & ~((inc) - 1))

static inline int update_pte_range(pmd_t *pmd, unsigned long addr,
                           unsigned long end,
                           struct host_vm_change *hvc)
{
      pte_t *pte;
      int r, w, x, prot, ret = 0;

      pte = pte_offset_kernel(pmd, addr);
      do {
            r = pte_read(*pte);
            w = pte_write(*pte);
            x = pte_exec(*pte);
            if (!pte_young(*pte)) {
                  r = 0;
                  w = 0;
            } else if (!pte_dirty(*pte)) {
                  w = 0;
            }
            prot = ((r ? UM_PROT_READ : 0) | (w ? UM_PROT_WRITE : 0) |
                  (x ? UM_PROT_EXEC : 0));
            if (hvc->force || pte_newpage(*pte)) {
                  if (pte_present(*pte))
                        ret = add_mmap(addr, pte_val(*pte) & PAGE_MASK,
                                     PAGE_SIZE, prot, hvc);
                  else ret = add_munmap(addr, PAGE_SIZE, hvc);
            }
            else if (pte_newprot(*pte))
                  ret = add_mprotect(addr, PAGE_SIZE, prot, hvc);
            *pte = pte_mkuptodate(*pte);
      } while (pte++, addr += PAGE_SIZE, ((addr != end) && !ret));
      return ret;
}

static inline int update_pmd_range(pud_t *pud, unsigned long addr,
                           unsigned long end,
                           struct host_vm_change *hvc)
{
      pmd_t *pmd;
      unsigned long next;
      int ret = 0;

      pmd = pmd_offset(pud, addr);
      do {
            next = pmd_addr_end(addr, end);
            if (!pmd_present(*pmd)) {
                  if (hvc->force || pmd_newpage(*pmd)) {
                        ret = add_munmap(addr, next - addr, hvc);
                        pmd_mkuptodate(*pmd);
                  }
            }
            else ret = update_pte_range(pmd, addr, next, hvc);
      } while (pmd++, addr = next, ((addr != end) && !ret));
      return ret;
}

static inline int update_pud_range(pgd_t *pgd, unsigned long addr,
                           unsigned long end,
                           struct host_vm_change *hvc)
{
      pud_t *pud;
      unsigned long next;
      int ret = 0;

      pud = pud_offset(pgd, addr);
      do {
            next = pud_addr_end(addr, end);
            if (!pud_present(*pud)) {
                  if (hvc->force || pud_newpage(*pud)) {
                        ret = add_munmap(addr, next - addr, hvc);
                        pud_mkuptodate(*pud);
                  }
            }
            else ret = update_pmd_range(pud, addr, next, hvc);
      } while (pud++, addr = next, ((addr != end) && !ret));
      return ret;
}

void fix_range_common(struct mm_struct *mm, unsigned long start_addr,
                  unsigned long end_addr, int force)
{
      pgd_t *pgd;
      struct host_vm_change hvc;
      unsigned long addr = start_addr, next;
      int ret = 0;

      hvc = INIT_HVC(mm, force);
      pgd = pgd_offset(mm, addr);
      do {
            next = pgd_addr_end(addr, end_addr);
            if (!pgd_present(*pgd)) {
                  if (force || pgd_newpage(*pgd)) {
                        ret = add_munmap(addr, next - addr, &hvc);
                        pgd_mkuptodate(*pgd);
                  }
            }
            else ret = update_pud_range(pgd, addr, next, &hvc);
      } while (pgd++, addr = next, ((addr != end_addr) && !ret));

      if (!ret)
            ret = do_ops(&hvc, hvc.index, 1);

      /* This is not an else because ret is modified above */
      if (ret) {
            printk(KERN_ERR "fix_range_common: failed, killing current "
                   "process\n");
            force_sig(SIGKILL, current);
      }
}

int flush_tlb_kernel_range_common(unsigned long start, unsigned long end)
{
      struct mm_struct *mm;
      pgd_t *pgd;
      pud_t *pud;
      pmd_t *pmd;
      pte_t *pte;
      unsigned long addr, last;
      int updated = 0, err;

      mm = &init_mm;
      for (addr = start; addr < end;) {
            pgd = pgd_offset(mm, addr);
            if (!pgd_present(*pgd)) {
                  last = ADD_ROUND(addr, PGDIR_SIZE);
                  if (last > end)
                        last = end;
                  if (pgd_newpage(*pgd)) {
                        updated = 1;
                        err = os_unmap_memory((void *) addr,
                                          last - addr);
                        if (err < 0)
                              panic("munmap failed, errno = %d\n",
                                    -err);
                  }
                  addr = last;
                  continue;
            }

            pud = pud_offset(pgd, addr);
            if (!pud_present(*pud)) {
                  last = ADD_ROUND(addr, PUD_SIZE);
                  if (last > end)
                        last = end;
                  if (pud_newpage(*pud)) {
                        updated = 1;
                        err = os_unmap_memory((void *) addr,
                                          last - addr);
                        if (err < 0)
                              panic("munmap failed, errno = %d\n",
                                    -err);
                  }
                  addr = last;
                  continue;
            }

            pmd = pmd_offset(pud, addr);
            if (!pmd_present(*pmd)) {
                  last = ADD_ROUND(addr, PMD_SIZE);
                  if (last > end)
                        last = end;
                  if (pmd_newpage(*pmd)) {
                        updated = 1;
                        err = os_unmap_memory((void *) addr,
                                          last - addr);
                        if (err < 0)
                              panic("munmap failed, errno = %d\n",
                                    -err);
                  }
                  addr = last;
                  continue;
            }

            pte = pte_offset_kernel(pmd, addr);
            if (!pte_present(*pte) || pte_newpage(*pte)) {
                  updated = 1;
                  err = os_unmap_memory((void *) addr,
                                    PAGE_SIZE);
                  if (err < 0)
                        panic("munmap failed, errno = %d\n",
                              -err);
                  if (pte_present(*pte))
                        map_memory(addr,
                                 pte_val(*pte) & PAGE_MASK,
                                 PAGE_SIZE, 1, 1, 1);
            }
            else if (pte_newprot(*pte)) {
                  updated = 1;
                  os_protect_memory((void *) addr, PAGE_SIZE, 1, 1, 1);
            }
            addr += PAGE_SIZE;
      }
      return updated;
}

void flush_tlb_page(struct vm_area_struct *vma, unsigned long address)
{
      pgd_t *pgd;
      pud_t *pud;
      pmd_t *pmd;
      pte_t *pte;
      struct mm_struct *mm = vma->vm_mm;
      void *flush = NULL;
      int r, w, x, prot, err = 0;
      struct mm_id *mm_id;

      address &= PAGE_MASK;
      pgd = pgd_offset(mm, address);
      if (!pgd_present(*pgd))
            goto kill;

      pud = pud_offset(pgd, address);
      if (!pud_present(*pud))
            goto kill;

      pmd = pmd_offset(pud, address);
      if (!pmd_present(*pmd))
            goto kill;

      pte = pte_offset_kernel(pmd, address);

      r = pte_read(*pte);
      w = pte_write(*pte);
      x = pte_exec(*pte);
      if (!pte_young(*pte)) {
            r = 0;
            w = 0;
      } else if (!pte_dirty(*pte)) {
            w = 0;
      }

      mm_id = &mm->context.id;
      prot = ((r ? UM_PROT_READ : 0) | (w ? UM_PROT_WRITE : 0) |
            (x ? UM_PROT_EXEC : 0));
      if (pte_newpage(*pte)) {
            if (pte_present(*pte)) {
                  unsigned long long offset;
                  int fd;

                  fd = phys_mapping(pte_val(*pte) & PAGE_MASK, &offset);
                  err = map(mm_id, address, PAGE_SIZE, prot, fd, offset,
                          1, &flush);
            }
            else err = unmap(mm_id, address, PAGE_SIZE, 1, &flush);
      }
      else if (pte_newprot(*pte))
            err = protect(mm_id, address, PAGE_SIZE, prot, 1, &flush);

      if (err)
            goto kill;

      *pte = pte_mkuptodate(*pte);

      return;

kill:
      printk(KERN_ERR "Failed to flush page for address 0x%lx\n", address);
      force_sig(SIGKILL, current);
}

pgd_t *pgd_offset_proc(struct mm_struct *mm, unsigned long address)
{
      return pgd_offset(mm, address);
}

pud_t *pud_offset_proc(pgd_t *pgd, unsigned long address)
{
      return pud_offset(pgd, address);
}

pmd_t *pmd_offset_proc(pud_t *pud, unsigned long address)
{
      return pmd_offset(pud, address);
}

pte_t *pte_offset_proc(pmd_t *pmd, unsigned long address)
{
      return pte_offset_kernel(pmd, address);
}

pte_t *addr_pte(struct task_struct *task, unsigned long addr)
{
      pgd_t *pgd = pgd_offset(task->mm, addr);
      pud_t *pud = pud_offset(pgd, addr);
      pmd_t *pmd = pmd_offset(pud, addr);

      return pte_offset_map(pmd, addr);
}

void flush_tlb_all(void)
{
      flush_tlb_mm(current->mm);
}

void flush_tlb_kernel_range(unsigned long start, unsigned long end)
{
      flush_tlb_kernel_range_common(start, end);
}

void flush_tlb_kernel_vm(void)
{
      flush_tlb_kernel_range_common(start_vm, end_vm);
}

void __flush_tlb_one(unsigned long addr)
{
      flush_tlb_kernel_range_common(addr, addr + PAGE_SIZE);
}

static void fix_range(struct mm_struct *mm, unsigned long start_addr,
                  unsigned long end_addr, int force)
{
      if (!proc_mm && (end_addr > STUB_START))
            end_addr = STUB_START;

      fix_range_common(mm, start_addr, end_addr, force);
}

void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
                 unsigned long end)
{
      if (vma->vm_mm == NULL)
            flush_tlb_kernel_range_common(start, end);
      else fix_range(vma->vm_mm, start, end, 0);
}

void flush_tlb_mm(struct mm_struct *mm)
{
      unsigned long end;

      /*
       * Don't bother flushing if this address space is about to be
       * destroyed.
       */
      if (atomic_read(&mm->mm_users) == 0)
            return;

      end = proc_mm ? task_size : STUB_START;
      fix_range(mm, 0, end, 0);
}

void force_flush_all(void)
{
      struct mm_struct *mm = current->mm;
      struct vm_area_struct *vma = mm->mmap;

      while (vma != NULL) {
            fix_range(mm, vma->vm_start, vma->vm_end, 1);
            vma = vma->vm_next;
      }
}

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