1 files changed, 344 insertions, 0 deletions

diff --git a/xenolinux-2.4.23-sparse/mm/mprotect.c b/xenolinux-2.4.23-sparse/mm/mprotect.c
new file mode 100644
index 0000000000..e618a3b74d
--- /dev/null
+++ b/xenolinux-2.4.23-sparse/mm/mprotect.c
@@ -0,0 +1,344 @@
+/*
+ *	linux/mm/mprotect.c
+ *
+ *  (C) Copyright 1994 Linus Torvalds
+ */
+#include <linux/slab.h>
+#include <linux/smp_lock.h>
+#include <linux/shm.h>
+#include <linux/mman.h>
+
+#include <asm/uaccess.h>
+#include <asm/pgalloc.h>
+#include <asm/pgtable.h>
+
+static inline void change_pte_range(pmd_t * pmd, unsigned long address,
+	unsigned long size, pgprot_t newprot)
+{
+	pte_t * pte;
+	unsigned long end;
+
+	if (pmd_none(*pmd))
+		return;
+	if (pmd_bad(*pmd)) {
+		pmd_ERROR(*pmd);
+		pmd_clear(pmd);
+		return;
+	}
+	pte = pte_offset(pmd, address);
+	address &= ~PMD_MASK;
+	end = address + size;
+	if (end > PMD_SIZE)
+		end = PMD_SIZE;
+	do {
+		if (pte_present(*pte)) {
+			pte_t entry;
+
+			/* Avoid an SMP race with hardware updated dirty/clean
+			 * bits by wiping the pte and then setting the new pte
+			 * into place.
+			 */
+			entry = ptep_get_and_clear(pte);
+			set_pte(pte, pte_modify(entry, newprot));
+		}
+		address += PAGE_SIZE;
+		pte++;
+	} while (address && (address < end));
+}
+
+static inline void change_pmd_range(pgd_t * pgd, unsigned long address,
+	unsigned long size, pgprot_t newprot)
+{
+	pmd_t * pmd;
+	unsigned long end;
+
+	if (pgd_none(*pgd))
+		return;
+	if (pgd_bad(*pgd)) {
+		pgd_ERROR(*pgd);
+		pgd_clear(pgd);
+		return;
+	}
+	pmd = pmd_offset(pgd, address);
+	address &= ~PGDIR_MASK;
+	end = address + size;
+	if (end > PGDIR_SIZE)
+		end = PGDIR_SIZE;
+	do {
+		change_pte_range(pmd, address, end - address, newprot);
+		address = (address + PMD_SIZE) & PMD_MASK;
+		pmd++;
+	} while (address && (address < end));
+}
+
+static void change_protection(unsigned long start, unsigned long end, pgprot_t newprot)
+{
+	pgd_t *dir;
+	unsigned long beg = start;
+
+	dir = pgd_offset(current->mm, start);
+	flush_cache_range(current->mm, beg, end);
+	if (start >= end)
+		BUG();
+	spin_lock(&current->mm->page_table_lock);
+	do {
+		change_pmd_range(dir, start, end - start, newprot);
+		start = (start + PGDIR_SIZE) & PGDIR_MASK;
+		dir++;
+	} while (start && (start < end));
+	spin_unlock(&current->mm->page_table_lock);
+	flush_tlb_range(current->mm, beg, end);
+	return;
+}
+
+static inline int mprotect_fixup_all(struct vm_area_struct * vma, struct vm_area_struct ** pprev,
+	int newflags, pgprot_t prot)
+{
+	struct vm_area_struct * prev = *pprev;
+	struct mm_struct * mm = vma->vm_mm;
+
+	if (prev && prev->vm_end == vma->vm_start && can_vma_merge(prev, newflags) &&
+	    !vma->vm_file && !(vma->vm_flags & VM_SHARED)) {
+		spin_lock(&mm->page_table_lock);
+		prev->vm_end = vma->vm_end;
+		__vma_unlink(mm, vma, prev);
+		spin_unlock(&mm->page_table_lock);
+
+		kmem_cache_free(vm_area_cachep, vma);
+		mm->map_count--;
+
+		return 0;
+	}
+
+	spin_lock(&mm->page_table_lock);
+	vma->vm_flags = newflags;
+	vma->vm_page_prot = prot;
+	spin_unlock(&mm->page_table_lock);
+
+	*pprev = vma;
+
+	return 0;
+}
+
+static inline int mprotect_fixup_start(struct vm_area_struct * vma, struct vm_area_struct ** pprev,
+	unsigned long end,
+	int newflags, pgprot_t prot)
+{
+	struct vm_area_struct * n, * prev = *pprev;
+
+	*pprev = vma;
+
+	if (prev && prev->vm_end == vma->vm_start && can_vma_merge(prev, newflags) &&
+	    !vma->vm_file && !(vma->vm_flags & VM_SHARED)) {
+		spin_lock(&vma->vm_mm->page_table_lock);
+		prev->vm_end = end;
+		vma->vm_start = end;
+		spin_unlock(&vma->vm_mm->page_table_lock);
+
+		return 0;
+	}
+	n = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
+	if (!n)
+		return -ENOMEM;
+	*n = *vma;
+	n->vm_end = end;
+	n->vm_flags = newflags;
+	n->vm_raend = 0;
+	n->vm_page_prot = prot;
+	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->vm_start) >> PAGE_SHIFT;
+	lock_vma_mappings(vma);
+	spin_lock(&vma->vm_mm->page_table_lock);
+	vma->vm_start = end;
+	__insert_vm_struct(current->mm, n);
+	spin_unlock(&vma->vm_mm->page_table_lock);
+	unlock_vma_mappings(vma);
+
+	return 0;
+}
+
+static inline int mprotect_fixup_end(struct vm_area_struct * vma, struct vm_area_struct ** pprev,
+	unsigned long start,
+	int newflags, pgprot_t prot)
+{
+	struct vm_area_struct * n;
+
+	n = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
+	if (!n)
+		return -ENOMEM;
+	*n = *vma;
+	n->vm_start = start;
+	n->vm_pgoff += (n->vm_start - vma->vm_start) >> PAGE_SHIFT;
+	n->vm_flags = newflags;
+	n->vm_raend = 0;
+	n->vm_page_prot = prot;
+	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);
+	spin_lock(&vma->vm_mm->page_table_lock);
+	vma->vm_end = start;
+	__insert_vm_struct(current->mm, n);
+	spin_unlock(&vma->vm_mm->page_table_lock);
+	unlock_vma_mappings(vma);
+
+	*pprev = n;
+
+	return 0;
+}
+
+static inline int mprotect_fixup_middle(struct vm_area_struct * vma, struct vm_area_struct ** pprev,
+	unsigned long start, unsigned long end,
+	int newflags, pgprot_t prot)
+{
+	struct vm_area_struct * left, * right;
+
+	left = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
+	if (!left)
+		return -ENOMEM;
+	right = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
+	if (!right) {
+		kmem_cache_free(vm_area_cachep, left);
+		return -ENOMEM;
+	}
+	*left = *vma;
+	*right = *vma;
+	left->vm_end = start;
+	right->vm_start = end;
+	right->vm_pgoff += (right->vm_start - left->vm_start) >> PAGE_SHIFT;
+	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_pgoff += (start - vma->vm_start) >> PAGE_SHIFT;
+	vma->vm_raend = 0;
+	vma->vm_page_prot = prot;
+	lock_vma_mappings(vma);
+	spin_lock(&vma->vm_mm->page_table_lock);
+	vma->vm_start = start;
+	vma->vm_end = end;
+	vma->vm_flags = newflags;
+	__insert_vm_struct(current->mm, left);
+	__insert_vm_struct(current->mm, right);
+	spin_unlock(&vma->vm_mm->page_table_lock);
+	unlock_vma_mappings(vma);
+
+	*pprev = right;
+
+	return 0;
+}
+
+static int mprotect_fixup(struct vm_area_struct * vma, struct vm_area_struct ** pprev,
+	unsigned long start, unsigned long end, unsigned int newflags)
+{
+	pgprot_t newprot;
+	int error;
+
+	if (newflags == vma->vm_flags) {
+		*pprev = vma;
+		return 0;
+	}
+	newprot = protection_map[newflags & 0xf];
+	if (start == vma->vm_start) {
+		if (end == vma->vm_end)
+			error = mprotect_fixup_all(vma, pprev, newflags, newprot);
+		else
+			error = mprotect_fixup_start(vma, pprev, end, newflags, newprot);
+	} else if (end == vma->vm_end)
+		error = mprotect_fixup_end(vma, pprev, start, newflags, newprot);
+	else
+		error = mprotect_fixup_middle(vma, pprev, start, end, newflags, newprot);
+
+	if (error)
+		return error;
+
+	change_protection(start, end, newprot);
+	return 0;
+}
+
+asmlinkage long sys_mprotect(unsigned long start, size_t len, unsigned long prot)
+{
+	unsigned long nstart, end, tmp;
+	struct vm_area_struct * vma, * next, * prev;
+	int error = -EINVAL;
+
+	if (start & ~PAGE_MASK)
+		return -EINVAL;
+	len = PAGE_ALIGN(len);
+	end = start + len;
+	if (end < start)
+		return -ENOMEM;
+	if (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC))
+		return -EINVAL;
+	if (end == start)
+		return 0;
+
+	down_write(&current->mm->mmap_sem);
+
+	vma = find_vma_prev(current->mm, start, &prev);
+	error = -ENOMEM;
+	if (!vma || vma->vm_start > start)
+		goto out;
+
+#if defined(CONFIG_XENO_PRIV)
+	/* mprotect() unsupported for I/O mappings in Xenolinux. */
+	error = -EINVAL;
+	if (vma->vm_flags & VM_IO)
+		goto out;
+#endif
+
+	for (nstart = start ; ; ) {
+		unsigned int newflags;
+		int last = 0;
+
+		/* Here we know that  vma->vm_start <= nstart < vma->vm_end. */
+
+		newflags = prot | (vma->vm_flags & ~(PROT_READ | PROT_WRITE | PROT_EXEC));
+		if ((newflags & ~(newflags >> 4)) & 0xf) {
+			error = -EACCES;
+			goto out;
+		}
+
+		if (vma->vm_end > end) {
+			error = mprotect_fixup(vma, &prev, nstart, end, newflags);
+			goto out;
+		}
+		if (vma->vm_end == end)
+			last = 1;
+
+		tmp = vma->vm_end;
+		next = vma->vm_next;
+		error = mprotect_fixup(vma, &prev, nstart, tmp, newflags);
+		if (error)
+			goto out;
+		if (last)
+			break;
+		nstart = tmp;
+		vma = next;
+		if (!vma || vma->vm_start != nstart) {
+			error = -ENOMEM;
+			goto out;
+		}
+	}
+	if (next && prev->vm_end == next->vm_start && can_vma_merge(next, prev->vm_flags) &&
+	    !prev->vm_file && !(prev->vm_flags & VM_SHARED)) {
+		spin_lock(&prev->vm_mm->page_table_lock);
+		prev->vm_end = next->vm_end;
+		__vma_unlink(prev->vm_mm, next, prev);
+		spin_unlock(&prev->vm_mm->page_table_lock);
+
+		kmem_cache_free(vm_area_cachep, next);
+		prev->vm_mm->map_count--;
+	}
+out:
+	up_write(&current->mm->mmap_sem);
+	return error;
+}