arch/um/kernel/tlb.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
  */

 #include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/sched/signal.h>

 #include <asm/tlbflush.h>
 #include <as-layout.h>
 #include <mem_user.h>
 #include <os.h>
 #include <skas.h>
 #include <kern_util.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 userspace;
 	int index;
 	struct mm_struct *mm;
 	void *data;
 	int force;
 };

 #define INIT_HVC(mm, force, userspace) \
 	((struct host_vm_change) \
 	 { .ops		= { { .type = NONE } },	\
 	   .mm		= mm, \
        	   .data	= NULL, \
 	   .userspace	= userspace, \
 	   .index	= 0, \
 	   .force	= force })

 static void report_enomem(void)
 {
 	printk(KERN_ERR "UML ran out of memory on the host side! "
 			"This can happen due to a memory limitation or "
 			"vm.max_map_count has been reached.\n");
 }

 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:
 			if (hvc->userspace)
 				ret = map(&hvc->mm->context.id, op->u.mmap.addr,
 					  op->u.mmap.len, op->u.mmap.prot,
 					  op->u.mmap.fd,
 					  op->u.mmap.offset, finished,
 					  &hvc->data);
 			else
 				map_memory(op->u.mmap.addr, op->u.mmap.offset,
 					   op->u.mmap.len, 1, 1, 1);
 			break;
 		case MUNMAP:
 			if (hvc->userspace)
 				ret = unmap(&hvc->mm->context.id,
 					    op->u.munmap.addr,
 					    op->u.munmap.len, finished,
 					    &hvc->data);
 			else
 				ret = os_unmap_memory(
 					(void *) op->u.munmap.addr,
 						      op->u.munmap.len);

 			break;
 		case MPROTECT:
 			if (hvc->userspace)
 				ret = protect(&hvc->mm->context.id,
 					      op->u.mprotect.addr,
 					      op->u.mprotect.len,
 					      op->u.mprotect.prot,
 					      finished, &hvc->data);
 			else
 				ret = os_protect_memory(
 					(void *) op->u.mprotect.addr,
 							op->u.mprotect.len,
 							1, 1, 1);
 			break;
 		default:
 			printk(KERN_ERR "Unknown op type %d in do_ops\n",
 			       op->type);
 			BUG();
 			break;
 		}
 	}

 	if (ret == -ENOMEM)
 		report_enomem();

 	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 = -1, ret = 0;

 	if (hvc->userspace)
 		fd = phys_mapping(phys, &offset);
 	else
 		offset = phys;
 	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)) {
 				if (pte_newpage(*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(p4d_t *p4d, unsigned long addr,
 				   unsigned long end,
 				   struct host_vm_change *hvc)
 {
 	pud_t *pud;
 	unsigned long next;
 	int ret = 0;

 	pud = pud_offset(p4d, 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;
 }

 static inline int update_p4d_range(pgd_t *pgd, unsigned long addr,
 				   unsigned long end,
 				   struct host_vm_change *hvc)
 {
 	p4d_t *p4d;
 	unsigned long next;
 	int ret = 0;

 	p4d = p4d_offset(pgd, addr);
 	do {
 		next = p4d_addr_end(addr, end);
 		if (!p4d_present(*p4d)) {
 			if (hvc->force || p4d_newpage(*p4d)) {
 				ret = add_munmap(addr, next - addr, hvc);
 				p4d_mkuptodate(*p4d);
 			}
 		} else
 			ret = update_pud_range(p4d, addr, next, hvc);
 	} while (p4d++, addr = next, ((addr < end) && !ret));
 	return ret;
 }

 static 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, userspace = 1;

 	hvc = INIT_HVC(mm, force, userspace);
 	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_p4d_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) {
 		struct mm_id *mm_idp = &current->mm->context.id;

 		printk(KERN_ERR "fix_range_common: failed, killing current "
 		       "process: %d\n", task_tgid_vnr(current));
 		mm_idp->kill = 1;
 	}
 }

 static int flush_tlb_kernel_range_common(unsigned long start, unsigned long end)
 {
 	struct mm_struct *mm;
 	pgd_t *pgd;
 	p4d_t *p4d;
 	pud_t *pud;
 	pmd_t *pmd;
 	pte_t *pte;
 	unsigned long addr, last;
 	int updated = 0, err = 0, force = 0, userspace = 0;
 	struct host_vm_change hvc;

 	mm = &init_mm;
 	hvc = INIT_HVC(mm, force, userspace);
 	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 = add_munmap(addr, last - addr, &hvc);
 				if (err < 0)
 					panic("munmap failed, errno = %d\n",
 					      -err);
 			}
 			addr = last;
 			continue;
 		}

 		p4d = p4d_offset(pgd, addr);
 		if (!p4d_present(*p4d)) {
 			last = ADD_ROUND(addr, P4D_SIZE);
 			if (last > end)
 				last = end;
 			if (p4d_newpage(*p4d)) {
 				updated = 1;
 				err = add_munmap(addr, last - addr, &hvc);
 				if (err < 0)
 					panic("munmap failed, errno = %d\n",
 					      -err);
 			}
 			addr = last;
 			continue;
 		}

 		pud = pud_offset(p4d, addr);
 		if (!pud_present(*pud)) {
 			last = ADD_ROUND(addr, PUD_SIZE);
 			if (last > end)
 				last = end;
 			if (pud_newpage(*pud)) {
 				updated = 1;
 				err = add_munmap(addr, last - addr, &hvc);
 				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 = add_munmap(addr, last - addr, &hvc);
 				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 = add_munmap(addr, PAGE_SIZE, &hvc);
 			if (err < 0)
 				panic("munmap failed, errno = %d\n",
 				      -err);
 			if (pte_present(*pte))
 				err = add_mmap(addr, pte_val(*pte) & PAGE_MASK,
 					       PAGE_SIZE, 0, &hvc);
 		}
 		else if (pte_newprot(*pte)) {
 			updated = 1;
 			err = add_mprotect(addr, PAGE_SIZE, 0, &hvc);
 		}
 		addr += PAGE_SIZE;
 	}
 	if (!err)
 		err = do_ops(&hvc, hvc.index, 1);

 	if (err < 0)
 		panic("flush_tlb_kernel failed, errno = %d\n", err);
 	return updated;
 }

 void flush_tlb_page(struct vm_area_struct *vma, unsigned long address)
 {
 	pgd_t *pgd;
 	p4d_t *p4d;
 	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;

 	p4d = p4d_offset(pgd, address);
 	if (!p4d_present(*p4d))
 		goto kill;

 	pud = pud_offset(p4d, 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) {
 		if (err == -ENOMEM)
 			report_enomem();

 		goto kill;
 	}

 	*pte = pte_mkuptodate(*pte);

 	return;

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

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

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

 	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);
 }
 EXPORT_SYMBOL(flush_tlb_range);

 void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
 			unsigned long end)
 {
 	fix_range(mm, start, end, 0);
 }

 void flush_tlb_mm(struct mm_struct *mm)
 {
 	struct vm_area_struct *vma;
 	VMA_ITERATOR(vmi, mm, 0);

 	for_each_vma(vmi, vma)
 		fix_range(mm, vma->vm_start, vma->vm_end, 0);
 }

 void force_flush_all(void)
 {
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
 	VMA_ITERATOR(vmi, mm, 0);

 	mmap_read_lock(mm);
 	for_each_vma(vmi, vma)
 		fix_range(mm, vma->vm_start, vma->vm_end, 1);
 	mmap_read_unlock(mm);
 }
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
	*/

	#include <linux/mm.h>
	#include <linux/module.h>
	#include <linux/sched/signal.h>

	#include <asm/tlbflush.h>
	#include <as-layout.h>
	#include <mem_user.h>
	#include <os.h>
	#include <skas.h>
	#include <kern_util.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 userspace;
	int index;
	struct mm_struct *mm;
	void *data;
	int force;
	};

	#define INIT_HVC(mm, force, userspace) \
	((struct host_vm_change) \
	{ .ops = { { .type = NONE } }, \
	.mm = mm, \
	.data = NULL, \
	.userspace = userspace, \
	.index = 0, \
	.force = force })

	static void report_enomem(void)
	{
	printk(KERN_ERR "UML ran out of memory on the host side! "
	"This can happen due to a memory limitation or "
	"vm.max_map_count has been reached.\n");
	}

	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:
	if (hvc->userspace)
	ret = map(&hvc->mm->context.id, op->u.mmap.addr,
	op->u.mmap.len, op->u.mmap.prot,
	op->u.mmap.fd,
	op->u.mmap.offset, finished,
	&hvc->data);
	else
	map_memory(op->u.mmap.addr, op->u.mmap.offset,
	op->u.mmap.len, 1, 1, 1);
	break;
	case MUNMAP:
	if (hvc->userspace)
	ret = unmap(&hvc->mm->context.id,
	op->u.munmap.addr,
	op->u.munmap.len, finished,
	&hvc->data);
	else
	ret = os_unmap_memory(
	(void *) op->u.munmap.addr,
	op->u.munmap.len);

	break;
	case MPROTECT:
	if (hvc->userspace)
	ret = protect(&hvc->mm->context.id,
	op->u.mprotect.addr,
	op->u.mprotect.len,
	op->u.mprotect.prot,
	finished, &hvc->data);
	else
	ret = os_protect_memory(
	(void *) op->u.mprotect.addr,
	op->u.mprotect.len,
	1, 1, 1);
	break;
	default:
	printk(KERN_ERR "Unknown op type %d in do_ops\n",
	op->type);
	BUG();
	break;
	}
	}

	if (ret == -ENOMEM)
	report_enomem();

	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 = -1, ret = 0;

	if (hvc->userspace)
	fd = phys_mapping(phys, &offset);
	else
	offset = phys;
	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)) {
	if (pte_newpage(*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(p4d_t *p4d, unsigned long addr,
	unsigned long end,
	struct host_vm_change *hvc)
	{
	pud_t *pud;
	unsigned long next;
	int ret = 0;

	pud = pud_offset(p4d, 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;
	}

	static inline int update_p4d_range(pgd_t *pgd, unsigned long addr,
	unsigned long end,
	struct host_vm_change *hvc)
	{
	p4d_t *p4d;
	unsigned long next;
	int ret = 0;

	p4d = p4d_offset(pgd, addr);
	do {
	next = p4d_addr_end(addr, end);
	if (!p4d_present(*p4d)) {
	if (hvc->force \|\| p4d_newpage(*p4d)) {
	ret = add_munmap(addr, next - addr, hvc);
	p4d_mkuptodate(*p4d);
	}
	} else
	ret = update_pud_range(p4d, addr, next, hvc);
	} while (p4d++, addr = next, ((addr < end) && !ret));
	return ret;
	}

	static 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, userspace = 1;

	hvc = INIT_HVC(mm, force, userspace);
	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_p4d_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) {
	struct mm_id *mm_idp = &current->mm->context.id;

	printk(KERN_ERR "fix_range_common: failed, killing current "
	"process: %d\n", task_tgid_vnr(current));
	mm_idp->kill = 1;
	}
	}

	static int flush_tlb_kernel_range_common(unsigned long start, unsigned long end)
	{
	struct mm_struct *mm;
	pgd_t *pgd;
	p4d_t *p4d;
	pud_t *pud;
	pmd_t *pmd;
	pte_t *pte;
	unsigned long addr, last;
	int updated = 0, err = 0, force = 0, userspace = 0;
	struct host_vm_change hvc;

	mm = &init_mm;
	hvc = INIT_HVC(mm, force, userspace);
	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 = add_munmap(addr, last - addr, &hvc);
	if (err < 0)
	panic("munmap failed, errno = %d\n",
	-err);
	}
	addr = last;
	continue;
	}

	p4d = p4d_offset(pgd, addr);
	if (!p4d_present(*p4d)) {
	last = ADD_ROUND(addr, P4D_SIZE);
	if (last > end)
	last = end;
	if (p4d_newpage(*p4d)) {
	updated = 1;
	err = add_munmap(addr, last - addr, &hvc);
	if (err < 0)
	panic("munmap failed, errno = %d\n",
	-err);
	}
	addr = last;
	continue;
	}

	pud = pud_offset(p4d, addr);
	if (!pud_present(*pud)) {
	last = ADD_ROUND(addr, PUD_SIZE);
	if (last > end)
	last = end;
	if (pud_newpage(*pud)) {
	updated = 1;
	err = add_munmap(addr, last - addr, &hvc);
	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 = add_munmap(addr, last - addr, &hvc);
	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 = add_munmap(addr, PAGE_SIZE, &hvc);
	if (err < 0)
	panic("munmap failed, errno = %d\n",
	-err);
	if (pte_present(*pte))
	err = add_mmap(addr, pte_val(*pte) & PAGE_MASK,
	PAGE_SIZE, 0, &hvc);
	}
	else if (pte_newprot(*pte)) {
	updated = 1;
	err = add_mprotect(addr, PAGE_SIZE, 0, &hvc);
	}
	addr += PAGE_SIZE;
	}
	if (!err)
	err = do_ops(&hvc, hvc.index, 1);

	if (err < 0)
	panic("flush_tlb_kernel failed, errno = %d\n", err);
	return updated;
	}

	void flush_tlb_page(struct vm_area_struct *vma, unsigned long address)
	{
	pgd_t *pgd;
	p4d_t *p4d;
	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;

	p4d = p4d_offset(pgd, address);
	if (!p4d_present(*p4d))
	goto kill;

	pud = pud_offset(p4d, 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) {
	if (err == -ENOMEM)
	report_enomem();

	goto kill;
	}

	pte = pte_mkuptodate(pte);

	return;

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

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

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

	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);
	}
	EXPORT_SYMBOL(flush_tlb_range);

	void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
	unsigned long end)
	{
	fix_range(mm, start, end, 0);
	}

	void flush_tlb_mm(struct mm_struct *mm)
	{
	struct vm_area_struct *vma;
	VMA_ITERATOR(vmi, mm, 0);

	for_each_vma(vmi, vma)
	fix_range(mm, vma->vm_start, vma->vm_end, 0);
	}

	void force_flush_all(void)
	{
	struct mm_struct *mm = current->mm;
	struct vm_area_struct *vma;
	VMA_ITERATOR(vmi, mm, 0);

	mmap_read_lock(mm);
	for_each_vma(vmi, vma)
	fix_range(mm, vma->vm_start, vma->vm_end, 1);
	mmap_read_unlock(mm);
	}