text: /*
   * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   * Licensed under the GPL
   */
  
  #include <linux/mm.h>
  #include <linux/sched.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 {
  		if ((addr >= STUB_START) && (addr < STUB_END))
  			continue;
  
  		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)
  {
  	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_range(struct mm_struct *mm, unsigned long start,
  			unsigned long end)
  {
  	/*
  	 * Don't bother flushing if this address space is about to be
  	 * destroyed.
  	 */
  	if (atomic_read(&mm->mm_users) == 0)
  		return;
  
  	fix_range(mm, start, end, 0);
  }
  
  void flush_tlb_mm(struct mm_struct *mm)
  {
  	struct vm_area_struct *vma = mm->mmap;
  
  	while (vma != NULL) {
  		fix_range(mm, vma->vm_start, vma->vm_end, 0);
  		vma = vma->vm_next;
  	}
  }
  
  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;
  	}
  }
  