diff -Naur host/arch/i386/config.in host-ptrace/arch/i386/config.in
--- host/arch/i386/config.in	Fri Aug  9 15:57:14 2002
+++ host-ptrace/arch/i386/config.in	Sun Nov 10 18:40:09 2002
@@ -291,6 +291,8 @@
    bool '    Use real mode APM BIOS call to power off' CONFIG_APM_REAL_MODE_POWER_OFF
 fi
 
+bool '/proc/mm' CONFIG_PROC_MM
+
 endmenu
 
 source drivers/mtd/Config.in
diff -Naur host/arch/i386/kernel/ldt.c host-ptrace/arch/i386/kernel/ldt.c
--- host/arch/i386/kernel/ldt.c	Fri Oct 26 00:01:41 2001
+++ host-ptrace/arch/i386/kernel/ldt.c	Sun Nov  3 18:37:48 2002
@@ -24,11 +24,12 @@
  * assured by user-space anyway. Writes are atomic, to protect
  * the security checks done on new descriptors.
  */
-static int read_ldt(void * ptr, unsigned long bytecount)
+static int read_ldt(struct task_struct *task, void * ptr, 
+		    unsigned long bytecount)
 {
 	int err;
 	unsigned long size;
-	struct mm_struct * mm = current->mm;
+	struct mm_struct * mm = task->mm;
 
 	err = 0;
 	if (!mm->context.segments)
@@ -64,9 +65,10 @@
 	return err;
 }
 
-static int write_ldt(void * ptr, unsigned long bytecount, int oldmode)
+static int write_ldt(struct task_struct *task, void * ptr, 
+		     unsigned long bytecount, int oldmode)
 {
-	struct mm_struct * mm = current->mm;
+	struct mm_struct * mm = task->mm;
 	__u32 entry_1, entry_2, *lp;
 	int error;
 	struct modify_ldt_ldt_s ldt_info;
@@ -148,23 +150,29 @@
 	return error;
 }
 
-asmlinkage int sys_modify_ldt(int func, void *ptr, unsigned long bytecount)
+int modify_ldt(struct task_struct *task, int func, void *ptr, 
+	       unsigned long bytecount)
 {
 	int ret = -ENOSYS;
 
 	switch (func) {
 	case 0:
-		ret = read_ldt(ptr, bytecount);
+		ret = read_ldt(task, ptr, bytecount);
 		break;
 	case 1:
-		ret = write_ldt(ptr, bytecount, 1);
+		ret = write_ldt(task, ptr, bytecount, 1);
 		break;
 	case 2:
 		ret = read_default_ldt(ptr, bytecount);
 		break;
 	case 0x11:
-		ret = write_ldt(ptr, bytecount, 0);
+		ret = write_ldt(task, ptr, bytecount, 0);
 		break;
 	}
 	return ret;
+}
+
+asmlinkage int sys_modify_ldt(int func, void *ptr, unsigned long bytecount)
+{
+	return(modify_ldt(current, func, ptr, bytecount));
 }
diff -Naur host/arch/i386/kernel/process.c host-ptrace/arch/i386/kernel/process.c
--- host/arch/i386/kernel/process.c	Fri Aug  9 15:57:14 2002
+++ host-ptrace/arch/i386/kernel/process.c	Wed Nov  6 22:12:45 2002
@@ -551,13 +551,11 @@
  * we do not have to muck with descriptors here, that is
  * done in switch_mm() as needed.
  */
-void copy_segments(struct task_struct *p, struct mm_struct *new_mm)
+void mm_copy_segments(struct mm_struct *old_mm, struct mm_struct *new_mm)
 {
-	struct mm_struct * old_mm;
 	void *old_ldt, *ldt;
 
 	ldt = NULL;
-	old_mm = current->mm;
 	if (old_mm && (old_ldt = old_mm->context.segments) != NULL) {
 		/*
 		 * Completely new LDT, we initialize it from the parent:
@@ -570,6 +568,16 @@
 	}
 	new_mm->context.segments = ldt;
 	new_mm->context.cpuvalid = ~0UL;	/* valid on all CPU's - they can't have stale data */
+}
+
+void copy_segments(struct task_struct *p, struct mm_struct *new_mm)
+{
+	mm_copy_segments(current->mm, new_mm);
+}
+
+void copy_task_segments(struct task_struct *from, struct mm_struct *new_mm)
+{
+	mm_copy_segments(from->mm, new_mm);
 }
 
 /*
diff -Naur host/arch/i386/kernel/ptrace.c host-ptrace/arch/i386/kernel/ptrace.c
--- host/arch/i386/kernel/ptrace.c	Fri Aug  9 15:57:14 2002
+++ host-ptrace/arch/i386/kernel/ptrace.c	Mon Nov 11 19:03:38 2002
@@ -147,6 +147,11 @@
 	put_stack_long(child, EFL_OFFSET, tmp);
 }
 
+extern int modify_ldt(struct task_struct *task, int func, void *ptr, 
+		      unsigned long bytecount);
+
+extern struct mm_struct *proc_mm_get_mm(int fd);
+
 asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
 {
 	struct task_struct *child;
@@ -415,6 +420,53 @@
 			child->ptrace |= PT_TRACESYSGOOD;
 		else
 			child->ptrace &= ~PT_TRACESYSGOOD;
+		ret = 0;
+		break;
+	}
+
+	case PTRACE_FAULTINFO: {
+		struct ptrace_faultinfo fault;
+
+		fault = ((struct ptrace_faultinfo) 
+			{ .is_write	= child->thread.error_code,
+			  .addr		= child->thread.cr2 });
+		ret = copy_to_user((unsigned long *) data, &fault, 
+				   sizeof(fault));
+		if(ret)
+			break;
+		break;
+	}
+	case PTRACE_SIGPENDING:
+		ret = copy_to_user((unsigned long *) data, 
+				   &child->pending.signal,
+				   sizeof(child->pending.signal));
+		break;
+
+	case PTRACE_LDT: {
+		struct ptrace_ldt ldt;
+
+		if(copy_from_user(&ldt, (unsigned long *) data, 
+				  sizeof(ldt))){
+			ret = -EIO;
+			break;
+		}
+		ret = modify_ldt(child, ldt.func, ldt.ptr, ldt.bytecount);
+		break;
+	}
+
+	case PTRACE_SWITCH_MM: {
+		struct mm_struct *old = child->mm;
+		struct mm_struct *new = proc_mm_get_mm(data);
+
+		if(IS_ERR(new)){
+			ret = PTR_ERR(new);
+			break;
+		}
+
+		atomic_inc(&new->mm_users);
+		child->mm = new;
+		child->active_mm = new;
+		mmput(old);
 		ret = 0;
 		break;
 	}
diff -Naur host/arch/i386/kernel/sys_i386.c host-ptrace/arch/i386/kernel/sys_i386.c
--- host/arch/i386/kernel/sys_i386.c	Mon Mar 19 15:35:09 2001
+++ host-ptrace/arch/i386/kernel/sys_i386.c	Mon Nov 11 17:23:25 2002
@@ -40,7 +40,7 @@
 }
 
 /* common code for old and new mmaps */
-static inline long do_mmap2(
+long do_mmap2(struct mm_struct *mm,
 	unsigned long addr, unsigned long len,
 	unsigned long prot, unsigned long flags,
 	unsigned long fd, unsigned long pgoff)
@@ -55,9 +55,9 @@
 			goto out;
 	}
 
-	down_write(&current->mm->mmap_sem);
-	error = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
-	up_write(&current->mm->mmap_sem);
+	down_write(&mm->mmap_sem);
+	error = do_mmap_pgoff(mm, file, addr, len, prot, flags, pgoff);
+	up_write(&mm->mmap_sem);
 
 	if (file)
 		fput(file);
@@ -69,7 +69,7 @@
 	unsigned long prot, unsigned long flags,
 	unsigned long fd, unsigned long pgoff)
 {
-	return do_mmap2(addr, len, prot, flags, fd, pgoff);
+	return do_mmap2(current->mm, addr, len, prot, flags, fd, pgoff);
 }
 
 /*
@@ -100,7 +100,7 @@
 	if (a.offset & ~PAGE_MASK)
 		goto out;
 
-	err = do_mmap2(a.addr, a.len, a.prot, a.flags, a.fd, a.offset >> PAGE_SHIFT);
+	err = do_mmap2(current->mm, a.addr, a.len, a.prot, a.flags, a.fd, a.offset >> PAGE_SHIFT);
 out:
 	return err;
 }
diff -Naur host/include/asm-i386/processor.h host-ptrace/include/asm-i386/processor.h
--- host/include/asm-i386/processor.h	Sun Nov 10 18:47:37 2002
+++ host-ptrace/include/asm-i386/processor.h	Mon Nov 11 17:33:30 2002
@@ -436,6 +436,8 @@
 extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
 
 /* Copy and release all segment info associated with a VM */
+extern void mm_copy_segments(struct mm_struct *old_mm, 
+			     struct mm_struct *new_mm);
 extern void copy_segments(struct task_struct *p, struct mm_struct * mm);
 extern void release_segments(struct mm_struct * mm);
 
diff -Naur host/include/asm-i386/ptrace.h host-ptrace/include/asm-i386/ptrace.h
--- host/include/asm-i386/ptrace.h	Sun Sep 23 19:20:51 2001
+++ host-ptrace/include/asm-i386/ptrace.h	Sun Nov 10 18:36:22 2002
@@ -51,6 +51,22 @@
 
 #define PTRACE_SETOPTIONS         21
 
+struct ptrace_faultinfo {
+	int is_write;
+	unsigned long addr;
+};
+
+struct ptrace_ldt {
+	int func;
+  	void *ptr;
+	unsigned long bytecount;
+};
+
+#define PTRACE_FAULTINFO 52
+#define PTRACE_SIGPENDING 53
+#define PTRACE_LDT 54
+#define PTRACE_SWITCH_MM 55
+
 /* options set using PTRACE_SETOPTIONS */
 #define PTRACE_O_TRACESYSGOOD     0x00000001
 
diff -Naur host/include/linux/mm.h host-ptrace/include/linux/mm.h
--- host/include/linux/mm.h	Fri Aug 30 15:03:44 2002
+++ host-ptrace/include/linux/mm.h	Mon Nov 11 19:08:53 2002
@@ -492,6 +492,9 @@
 int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, unsigned long start,
 		int len, int write, int force, struct page **pages, struct vm_area_struct **vmas);
 
+extern long do_mprotect(struct mm_struct *mm, unsigned long start, 
+			size_t len, unsigned long prot);
+
 /*
  * On a two-level page table, this ends up being trivial. Thus the
  * inlining and the symmetry break with pte_alloc() that does all
@@ -539,9 +542,10 @@
 
 extern unsigned long get_unmapped_area(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
 
-extern unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
-	unsigned long len, unsigned long prot,
-	unsigned long flag, unsigned long pgoff);
+extern unsigned long do_mmap_pgoff(struct mm_struct *mm, 
+				   struct file *file, unsigned long addr,
+				   unsigned long len, unsigned long prot,
+				   unsigned long flag, unsigned long pgoff);
 
 static inline unsigned long do_mmap(struct file *file, unsigned long addr,
 	unsigned long len, unsigned long prot,
@@ -551,7 +555,7 @@
 	if ((offset + PAGE_ALIGN(len)) < offset)
 		goto out;
 	if (!(offset & ~PAGE_MASK))
-		ret = do_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT);
+		ret = do_mmap_pgoff(current->mm, file, addr, len, prot, flag, offset >> PAGE_SHIFT);
 out:
 	return ret;
 }
diff -Naur host/include/linux/proc_mm.h host-ptrace/include/linux/proc_mm.h
--- host/include/linux/proc_mm.h	Wed Dec 31 19:00:00 1969
+++ host-ptrace/include/linux/proc_mm.h	Mon Nov 11 17:41:09 2002
@@ -0,0 +1,44 @@
+/* 
+ * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
+ * Licensed under the GPL
+ */
+
+#ifndef __PROC_MM_H
+#define __PROC_MM_H
+
+#define MM_MMAP 54
+#define MM_MUNMAP 55
+#define MM_MPROTECT 56
+#define MM_COPY_SEGMENTS 57
+
+struct mm_mmap {
+	unsigned long addr;
+	unsigned long len;
+	unsigned long prot;
+	unsigned long flags;
+	unsigned long fd;
+	unsigned long offset;
+};
+
+struct mm_munmap {
+	unsigned long addr;
+	unsigned long len;	
+};
+
+struct mm_mprotect {
+	unsigned long addr;
+	unsigned long len;
+        unsigned int prot;
+};
+
+struct proc_mm_op {
+	int op;
+	union {
+		struct mm_mmap mmap;
+		struct mm_munmap munmap;
+	        struct mm_mprotect mprotect;
+		int copy_segments;
+	} u;
+};
+
+#endif
diff -Naur host/mm/Makefile host-ptrace/mm/Makefile
--- host/mm/Makefile	Fri Aug  9 15:57:31 2002
+++ host-ptrace/mm/Makefile	Sun Nov 10 18:37:33 2002
@@ -17,5 +17,6 @@
 	    shmem.o
 
 obj-$(CONFIG_HIGHMEM) += highmem.o
+obj-$(CONFIG_PROC_MM) += proc_mm.o
 
 include $(TOPDIR)/Rules.make
diff -Naur host/mm/mmap.c host-ptrace/mm/mmap.c
--- host/mm/mmap.c	Fri Aug  9 15:57:31 2002
+++ host-ptrace/mm/mmap.c	Mon Nov 11 17:24:18 2002
@@ -390,10 +390,11 @@
 	return 0;
 }
 
-unsigned long do_mmap_pgoff(struct file * file, unsigned long addr, unsigned long len,
-	unsigned long prot, unsigned long flags, unsigned long pgoff)
+unsigned long do_mmap_pgoff(struct mm_struct *mm, struct file * file, 
+			    unsigned long addr, unsigned long len,
+			    unsigned long prot, unsigned long flags, 
+			    unsigned long pgoff)
 {
-	struct mm_struct * mm = current->mm;
 	struct vm_area_struct * vma, * prev;
 	unsigned int vm_flags;
 	int correct_wcount = 0;
diff -Naur host/mm/mprotect.c host-ptrace/mm/mprotect.c
--- host/mm/mprotect.c	Fri Aug  9 15:57:31 2002
+++ host-ptrace/mm/mprotect.c	Mon Nov 11 17:47:58 2002
@@ -264,7 +264,8 @@
 	return 0;
 }
 
-asmlinkage long sys_mprotect(unsigned long start, size_t len, unsigned long prot)
+long do_mprotect(struct mm_struct *mm, unsigned long start, size_t len, 
+		 unsigned long prot)
 {
 	unsigned long nstart, end, tmp;
 	struct vm_area_struct * vma, * next, * prev;
@@ -281,9 +282,9 @@
 	if (end == start)
 		return 0;
 
-	down_write(&current->mm->mmap_sem);
+	down_write(&mm->mmap_sem);
 
-	vma = find_vma_prev(current->mm, start, &prev);
+	vma = find_vma_prev(mm, start, &prev);
 	error = -ENOMEM;
 	if (!vma || vma->vm_start > start)
 		goto out;
@@ -332,6 +333,11 @@
 		prev->vm_mm->map_count--;
 	}
 out:
-	up_write(&current->mm->mmap_sem);
+	up_write(&mm->mmap_sem);
 	return error;
+}
+
+asmlinkage long sys_mprotect(unsigned long start, size_t len, unsigned long prot)
+{
+	return(do_mprotect(current->mm, start, len, prot));
 }
diff -Naur host/mm/proc_mm.c host-ptrace/mm/proc_mm.c
--- host/mm/proc_mm.c	Wed Dec 31 19:00:00 1969
+++ host-ptrace/mm/proc_mm.c	Mon Nov 11 19:07:52 2002
@@ -0,0 +1,173 @@
+/* 
+ * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
+ * Licensed under the GPL
+ */
+
+#include "linux/proc_fs.h"
+#include "linux/proc_mm.h"
+#include "linux/file.h"
+#include "asm/uaccess.h"
+#include "asm/mmu_context.h"
+
+static struct file_operations proc_mm_fops;
+
+struct mm_struct *proc_mm_get_mm(int fd)
+{
+	struct mm_struct *ret = ERR_PTR(-EBADF);
+	struct file *file;
+
+	file = fget(fd);
+	if (!file)
+		goto out;
+
+	ret = ERR_PTR(-EINVAL);
+	if(file->f_op != &proc_mm_fops)
+		goto out_fput;
+
+	ret = file->private_data;
+
+ out_fput:
+	fput(file);
+ out:
+	return(ret);
+}
+
+extern long do_mmap2(struct mm_struct *mm, unsigned long addr, 
+		     unsigned long len, unsigned long prot, 
+		     unsigned long flags, unsigned long fd,
+		     unsigned long pgoff);
+
+static ssize_t write_proc_mm(struct file *file, const char *buffer,
+			     size_t count, loff_t *ppos)
+{
+	struct mm_struct *mm = file->private_data;
+	struct proc_mm_op req;
+	int n, ret;
+
+	if(count > sizeof(req))
+		return(-EINVAL);
+
+	n = copy_from_user(&req, buffer, count);
+	if(n != 0)
+		return(-EFAULT);
+
+	ret = count;
+	switch(req.op){
+	case MM_MMAP: {
+		struct mm_mmap *map = &req.u.mmap;
+
+		ret = do_mmap2(mm, map->addr, map->len, map->prot, 
+			       map->flags, map->fd, map->offset >> PAGE_SHIFT);
+		if((ret & ~PAGE_MASK) == 0)
+			ret = count;
+	
+		break;
+	}
+	case MM_MUNMAP: {
+		struct mm_munmap *unmap = &req.u.munmap;
+
+		down_write(&mm->mmap_sem);
+		ret = do_munmap(mm, unmap->addr, unmap->len);
+		up_write(&mm->mmap_sem);
+
+		if(ret == 0)
+			ret = count;
+		break;
+	}
+	case MM_MPROTECT: {
+		struct mm_mprotect *protect = &req.u.mprotect;
+
+		ret = do_mprotect(mm, protect->addr, protect->len, 
+				  protect->prot);
+		if(ret == 0)
+			ret = count;
+		break;
+	}
+
+	case MM_COPY_SEGMENTS: {
+		struct mm_struct *from = proc_mm_get_mm(req.u.copy_segments);
+
+		if(IS_ERR(from)){
+			ret = PTR_ERR(from);
+			break;
+		}
+
+		mm_copy_segments(from, mm);
+		break;
+	}
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	return(ret);
+}
+
+static int open_proc_mm(struct inode *inode, struct file *file)
+{
+	struct mm_struct *mm = mm_alloc();
+	int ret;
+
+	ret = -ENOMEM;
+	if(mm == NULL)
+		goto out_mem;
+
+	ret = init_new_context(current, mm);
+	if(ret)
+		goto out_free;
+
+	spin_lock(&mmlist_lock);
+	list_add(&mm->mmlist, &current->mm->mmlist);
+	mmlist_nr++;
+	spin_unlock(&mmlist_lock);
+
+	file->private_data = mm;
+
+	return(0);
+
+ out_free:
+	mmput(mm);
+ out_mem:
+	return(ret);
+}
+
+static int release_proc_mm(struct inode *inode, struct file *file)
+{
+	struct mm_struct *mm = file->private_data;
+
+	mmput(mm);
+	return(0);
+}
+
+static struct file_operations proc_mm_fops = {
+	.open		= open_proc_mm,
+	.release	= release_proc_mm,
+	.write		= write_proc_mm,
+};
+
+static int make_proc_mm(void)
+{
+	struct proc_dir_entry *ent;
+
+	ent = create_proc_entry("mm", 0222, &proc_root);
+	if(ent == NULL){
+		printk("make_proc_mm : Failed to register /proc/mm\n");
+		return(0);
+	}
+	ent->proc_fops = &proc_mm_fops;
+
+	return(0);
+}
+
+__initcall(make_proc_mm);
+
+/*
+ * Overrides for Emacs so that we follow Linus's tabbing style.
+ * Emacs will notice this stuff at the end of the file and automatically
+ * adjust the settings for this buffer only.  This must remain at the end
+ * of the file.
+ * ---------------------------------------------------------------------------
+ * Local variables:
+ * c-file-style: "linux"
+ * End:
+ */