linux/arch/um/kernel/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"

static int add_mmap(unsigned long virt, unsigned long phys, unsigned long len,
		    unsigned int prot, struct host_vm_op *ops, int *index,
		    int last_filled, struct mm_context *mmu, void **flush,
		    int (*do_ops)(struct mm_context *, struct host_vm_op *,
				  int, int, void **))
{
	__u64 offset;
	struct host_vm_op *last;
	int fd, ret = 0;

	fd = phys_mapping(phys, &offset);
	if (*index != -1) {
		last = &ops[*index];
		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 (*index == last_filled) {
		ret = (*do_ops)(mmu, ops, last_filled, 0, flush);
		*index = -1;
	}

	ops[++*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_op *ops, int *index, int last_filled,
		      struct mm_context *mmu, void **flush,
		      int (*do_ops)(struct mm_context *, struct host_vm_op *,
				    int, int, void **))
{
	struct host_vm_op *last;
	int ret = 0;

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

	if (*index == last_filled) {
		ret = (*do_ops)(mmu, ops, last_filled, 0, flush);
		*index = -1;
	}

	ops[++*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_op *ops, int *index,
			int last_filled, struct mm_context *mmu, void **flush,
			int (*do_ops)(struct mm_context *, struct host_vm_op *,
				      int, int, void **))
{
	struct host_vm_op *last;
	int ret = 0;

	if (*index != -1) {
		last = &ops[*index];
		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 (*index == last_filled) {
		ret = (*do_ops)(mmu, ops, last_filled, 0, flush);
		*index = -1;
	}

	ops[++*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_op *ops,
				   int last_op, int *op_index, int force,
				   struct mm_context *mmu, void **flush,
				   int (*do_ops)(struct mm_context *,
						 struct host_vm_op *, int, int,
						 void **))
{
	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 (force || pte_newpage(*pte)) {
			if (pte_present(*pte))
				ret = add_mmap(addr, pte_val(*pte) & PAGE_MASK,
					       PAGE_SIZE, prot, ops, op_index,
					       last_op, mmu, flush, do_ops);
			else ret = add_munmap(addr, PAGE_SIZE, ops, op_index,
					      last_op, mmu, flush, do_ops);
		}
		else if (pte_newprot(*pte))
			ret = add_mprotect(addr, PAGE_SIZE, prot, ops, op_index,
					   last_op, mmu, flush, do_ops);
		*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_op *ops,
				   int last_op, int *op_index, int force,
				   struct mm_context *mmu, void **flush,
				   int (*do_ops)(struct mm_context *,
						 struct host_vm_op *, int, int,
						 void **))
{
	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 (force || pmd_newpage(*pmd)) {
				ret = add_munmap(addr, next - addr, ops,
						 op_index, last_op, mmu,
						 flush, do_ops);
				pmd_mkuptodate(*pmd);
			}
		}
		else ret = update_pte_range(pmd, addr, next, ops, last_op,
					    op_index, force, mmu, flush,
					    do_ops);
	} 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_op *ops,
				   int last_op, int *op_index, int force,
				   struct mm_context *mmu, void **flush,
				   int (*do_ops)(struct mm_context *,
						 struct host_vm_op *, int, int,
						 void **))
{
	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 (force || pud_newpage(*pud)) {
				ret = add_munmap(addr, next - addr, ops,
						 op_index, last_op, mmu,
						 flush, do_ops);
				pud_mkuptodate(*pud);
			}
		}
		else ret = update_pmd_range(pud, addr, next, ops, last_op,
					    op_index, force, mmu, flush,
					    do_ops);
	} 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,
		      int (*do_ops)(struct mm_context *, struct host_vm_op *,
				    int, int, void **))
{
	pgd_t *pgd;
	struct mm_context *mmu = &mm->context;
	struct host_vm_op ops[1];
	unsigned long addr = start_addr, next;
	int ret = 0, last_op = ARRAY_SIZE(ops) - 1, op_index = -1;
	void *flush = NULL;

	ops[0].type = NONE;
	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, ops,
						 &op_index, last_op, mmu,
						 &flush, do_ops);
				pgd_mkuptodate(*pgd);
			}
		}
		else ret = update_pud_range(pgd, addr, next, ops, last_op,
					    &op_index, force, mmu, &flush,
					    do_ops);
	} while (pgd++, addr = next, ((addr != end_addr) && !ret));

	if (!ret)
		ret = (*do_ops)(mmu, ops, op_index, 1, &flush);

	/* 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 int do_ops(struct mm_context *mmu, struct host_vm_op *ops, int last,
		  int finished, void **flush)
{
	struct host_vm_op *op;
	int i, ret = 0;

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

	return ret;
}

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

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

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 : CONFIG_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;
	}
}