tlb.c

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

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

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);
            BUG();
            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);
    }
}

static 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);
}
EXPORT_SYMBOL(flush_tlb_range);

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;
    }
}