sys/src/vmsmlock.c

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// _Id: vmsmlock.c,v 1.7 2006-03-09 10:47:59 roart Exp $
// _Locker:  $

// Author. Roar Thronæs.
// Modified Linux source file, 2001-2004. Based on mlock.c.

/*
 *      linux/mm/mlock.c
 *
 *  (C) Copyright 1995 Linus Torvalds
 */
#include <linux/config.h>
#include <linux/slab.h>
#include <linux/shm.h>
#include <linux/mman.h>
#include <linux/smp_lock.h>
#include <linux/pagemap.h>

#include <asm/uaccess.h>
#include <asm/pgtable.h>

#include <ipldef.h>
#include <phddef.h>
#include <rdedef.h>
#include <misc_routines.h>

static inline int mlock_fixup_all(struct _rde * vma, int newflags)
{
  //spin_lock(&vma->vm_mm->page_table_lock);
        vma->rde_l_flags = newflags;
        //spin_unlock(&vma->vm_mm->page_table_lock);
        return 0;
}

static inline int mlock_fixup_start(struct _rde * vma,
        unsigned long end, int newflags)
{
        struct _rde * n;

        n = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
        if (!n)
                return -EAGAIN;
        *n = *vma;
        n->rde_q_region_size = end - (unsigned long)n->rde$pq_start_va;
        n->rde_l_flags = newflags;
        //n->vm_raend = 0;
#if 0
        if (n->vm_file)
                get_file(n->vm_file);
        if (n->vm_ops && n->vm_ops->open)
                n->vm_ops->open(n);
        vma->vm_pgoff += (end - vma->rde_pq_start_va) >> PAGE_SHIFT;
#endif
        lock_vma_mappings(vma);
        //spin_lock(&vma->vm_mm->page_table_lock);
        vma->rde_pq_start_va = end;
        //__insert_vm_struct(current->mm, n);
        insrde(n,&current->pcb_l_phd->phd$ps_p0_va_list_flink);
        //spin_unlock(&vma->vm_mm->page_table_lock);
        unlock_vma_mappings(vma);
        return 0;
}

static inline int mlock_fixup_end(struct _rde * vma,
        unsigned long start, int newflags)
{
        struct _rde * n;

        n = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
        if (!n)
                return -EAGAIN;
        *n = *vma;
        n->rde_pq_start_va = start;
        //n->vm_pgoff += (n->rde_pq_start_va - vma->rde$pq_start_va) >> PAGE_SHIFT;
        n->rde_l_flags = newflags;
#if 0
        n->vm_raend = 0;
        if (n->vm_file)
                get_file(n->vm_file);
        if (n->vm_ops && n->vm_ops->open)
                n->vm_ops->open(n);
        lock_vma_mappings(vma);
#endif
        //spin_lock(&vma->vm_mm->page_table_lock);
        vma->rde_q_region_size = start - (unsigned long)vma->rde$pq_start_va;
        //__insert_vm_struct(current->mm, n);
        insrde(n,&current->pcb_l_phd->phd$ps_p0_va_list_flink);
        //spin_unlock(&vma->vm_mm->page_table_lock);
        unlock_vma_mappings(vma);
        return 0;
}

static inline int mlock_fixup_middle(struct _rde * vma,
        unsigned long start, unsigned long end, int newflags)
{
        struct _rde * left, * right;

        left = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
        if (!left)
                return -EAGAIN;
        right = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
        if (!right) {
                kmem_cache_free(vm_area_cachep, left);
                return -EAGAIN;
        }
        *left = *vma;
        *right = *vma;
        left->rde_q_region_size = start - (unsigned long)left->rde$pq_start_va;
        right->rde_pq_start_va = end;
#if 0
        right->vm_pgoff += (right->rde_pq_start_va - left->rde$pq_start_va) >> PAGE_SHIFT;
#endif
        vma->rde_l_flags = newflags;
#if 0
        left->vm_raend = 0;
        right->vm_raend = 0;
        if (vma->vm_file)
                atomic_add(2, &vma->vm_file->f_count);

        if (vma->vm_ops && vma->vm_ops->open) {
                vma->vm_ops->open(left);
                vma->vm_ops->open(right);
        }
        vma->vm_raend = 0;
        vma->vm_pgoff += (start - vma->rde_pq_start_va) >> PAGE_SHIFT;
#endif
        lock_vma_mappings(vma);
        //spin_lock(&vma->vm_mm->page_table_lock);
        vma->rde_pq_start_va = start;
        vma->rde_q_region_size = end - (unsigned long)vma->rde$pq_start_va;
        vma->rde_l_flags = newflags;
        //__insert_vm_struct(current->mm, left);
        insrde(left,&current->pcb_l_phd->phd$ps_p0_va_list_flink);
        //__insert_vm_struct(current->mm, right);
        insrde(right,&current->pcb_l_phd->phd$ps_p0_va_list_flink);
        //spin_unlock(&vma->vm_mm->page_table_lock);
        unlock_vma_mappings(vma);
        return 0;
}

static int mlock_fixup(struct _rde * vma, 
        unsigned long start, unsigned long end, unsigned int newflags)
{
        int pages, retval;

        if (newflags == vma->rde_l_flags)
                return 0;

        if (start == vma->rde_pq_start_va) {
                if (end == (vma->rde_pq_start_va + vma->rde$q_region_size))
                        retval = mlock_fixup_all(vma, newflags);
                else
                        retval = mlock_fixup_start(vma, end, newflags);
        } else {
                if (end == (vma->rde_pq_start_va + vma->rde$q_region_size))
                        retval = mlock_fixup_end(vma, start, newflags);
                else
                        retval = mlock_fixup_middle(vma, start, end, newflags);
        }
        if (!retval) {
                /* keep track of amount of locked VM */
                pages = (end - start) >> PAGE_SHIFT;
                if (newflags & VM_LOCKED) {
                        pages = -pages;
                        make_pages_present(start, end);
                }
                //vma->vm_mm->locked_vm -= pages;
        }
        return retval;
}

static int do_mlock(unsigned long start, size_t len, int on)
{
        unsigned long nstart, end, tmp;
        struct _rde * vma, * next;
        int error;

        if (on && !capable(CAP_IPC_LOCK))
                return -EPERM;
        len = PAGE_ALIGN(len);
        end = start + len;
        if (end < start)
                return -EINVAL;
        if (end == start)
                return 0;
        //vma = find_vma(current->mm, start);
        vma = find_vma(current->pcb_l_phd,start);
        if (!vma || vma->rde_pq_start_va > start)
                return -ENOMEM;

        for (nstart = start ; ; ) {
                unsigned int newflags;

                /* Here we know that  vma->rde_pq_start_va <= nstart < (vma->rde$pq_start_va + vma->rde$q_region_size). */

                newflags = vma->rde_l_flags | VM_LOCKED;
                if (!on)
                        newflags &= ~VM_LOCKED;

                if ((vma->rde_pq_start_va + vma->rde$q_region_size) >= end) {
                        error = mlock_fixup(vma, nstart, end, newflags);
                        break;
                }

                tmp = (vma->rde_pq_start_va + vma->rde$q_region_size);
                next = vma->rde_ps_va_list_flink;
                error = mlock_fixup(vma, nstart, tmp, newflags);
                if (error)
                        break;
                nstart = tmp;
                vma = next;
                if (!vma || vma->rde_pq_start_va != nstart) {
                        error = -ENOMEM;
                        break;
                }
        }
        return error;
}

asmlinkage long sys_mlock(unsigned long start, size_t len)
{
        unsigned long locked;
        unsigned long lock_limit;
        int error = -ENOMEM;

        down_write(&current->mm->mmap_sem);
        len = PAGE_ALIGN(len + (start & ~PAGE_MASK));
        start &= PAGE_MASK;

        locked = len >> PAGE_SHIFT;
        locked += current->mm->locked_vm;

        lock_limit = current->rlim[RLIMIT_MEMLOCK].rlim_cur;
        lock_limit >>= PAGE_SHIFT;

        /* check against resource limits */
        if (locked > lock_limit)
                goto out;

        /* we may lock at most half of physical memory... */
        /* (this check is pretty bogus, but doesn't hurt) */
        if (locked > num_physpages/2)
                goto out;

        error = do_mlock(start, len, 1);
out:
        up_write(&current->mm->mmap_sem);
        return error;
}

asmlinkage long sys_munlock(unsigned long start, size_t len)
{
        int ret;

        down_write(&current->mm->mmap_sem);
        len = PAGE_ALIGN(len + (start & ~PAGE_MASK));
        start &= PAGE_MASK;
        ret = do_mlock(start, len, 0);
        up_write(&current->mm->mmap_sem);
        return ret;
}

static int do_mlockall(int flags)
{
        int error;
        unsigned int def_flags;
        struct _rde * vma;

        if (!capable(CAP_IPC_LOCK))
                return -EPERM;

        def_flags = 0;
        if (flags & MCL_FUTURE)
                def_flags = VM_LOCKED;
        current->mm->def_flags = def_flags;

        error = 0;
        for (vma = current->mm->mmap; vma ; vma = vma->rde_ps_va_list_flink) {
                unsigned int newflags;

                newflags = vma->rde_l_flags | VM_LOCKED;
                if (!(flags & MCL_CURRENT))
                        newflags &= ~VM_LOCKED;
                error = mlock_fixup(vma, vma->rde_pq_start_va, (vma->rde$pq_start_va + vma->rde$q_region_size), newflags);
                if (error)
                        break;
        }
        return error;
}

asmlinkage long sys_mlockall(int flags)
{
        unsigned long lock_limit;
        int ret = -EINVAL;

        down_write(&current->mm->mmap_sem);
        if (!flags || (flags & ~(MCL_CURRENT | MCL_FUTURE)))
                goto out;

        lock_limit = current->rlim[RLIMIT_MEMLOCK].rlim_cur;
        lock_limit >>= PAGE_SHIFT;

        ret = -ENOMEM;
        if (current->mm->total_vm > lock_limit)
                goto out;

        /* we may lock at most half of physical memory... */
        /* (this check is pretty bogus, but doesn't hurt) */
        if (current->mm->total_vm > num_physpages/2)
                goto out;

        ret = do_mlockall(flags);
out:
        up_write(&current->mm->mmap_sem);
        return ret;
}

asmlinkage long sys_munlockall(void)
{
        int ret;

        down_write(&current->mm->mmap_sem);
        ret = do_mlockall(0);
        up_write(&current->mm->mmap_sem);
        return ret;
}

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