i386: prepare shared kernel/vm86.c

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 0 insertions, 843 deletions

diff --git a/arch/i386/kernel/vm86.c b/arch/i386/kernel/vm86.c
deleted file mode 100644
index f2dcd1d..0000000
--- a/arch/i386/kernel/vm86.c
+++ /dev/null
@@ -1,843 +0,0 @@
-/*
- *  linux/kernel/vm86.c
- *
- *  Copyright (C) 1994  Linus Torvalds
- *
- *  29 dec 2001 - Fixed oopses caused by unchecked access to the vm86
- *                stack - Manfred Spraul <manfred@colorfullife.com>
- *
- *  22 mar 2002 - Manfred detected the stackfaults, but didn't handle
- *                them correctly. Now the emulation will be in a
- *                consistent state after stackfaults - Kasper Dupont
- *                <kasperd@daimi.au.dk>
- *
- *  22 mar 2002 - Added missing clear_IF in set_vflags_* Kasper Dupont
- *                <kasperd@daimi.au.dk>
- *
- *  ?? ??? 2002 - Fixed premature returns from handle_vm86_fault
- *                caused by Kasper Dupont's changes - Stas Sergeev
- *
- *   4 apr 2002 - Fixed CHECK_IF_IN_TRAP broken by Stas' changes.
- *                Kasper Dupont <kasperd@daimi.au.dk>
- *
- *   9 apr 2002 - Changed syntax of macros in handle_vm86_fault.
- *                Kasper Dupont <kasperd@daimi.au.dk>
- *
- *   9 apr 2002 - Changed stack access macros to jump to a label
- *                instead of returning to userspace. This simplifies
- *                do_int, and is needed by handle_vm6_fault. Kasper
- *                Dupont <kasperd@daimi.au.dk>
- *
- */
-
-#include <linux/capability.h>
-#include <linux/errno.h>
-#include <linux/interrupt.h>
-#include <linux/sched.h>
-#include <linux/kernel.h>
-#include <linux/signal.h>
-#include <linux/string.h>
-#include <linux/mm.h>
-#include <linux/smp.h>
-#include <linux/highmem.h>
-#include <linux/ptrace.h>
-#include <linux/audit.h>
-#include <linux/stddef.h>
-
-#include <asm/uaccess.h>
-#include <asm/io.h>
-#include <asm/tlbflush.h>
-#include <asm/irq.h>
-
-/*
- * Known problems:
- *
- * Interrupt handling is not guaranteed:
- * - a real x86 will disable all interrupts for one instruction
- *   after a "mov ss,xx" to make stack handling atomic even without
- *   the 'lss' instruction. We can't guarantee this in v86 mode,
- *   as the next instruction might result in a page fault or similar.
- * - a real x86 will have interrupts disabled for one instruction
- *   past the 'sti' that enables them. We don't bother with all the
- *   details yet.
- *
- * Let's hope these problems do not actually matter for anything.
- */
-
-
-#define KVM86	((struct kernel_vm86_struct *)regs)
-#define VMPI 	KVM86->vm86plus
-
-
-/*
- * 8- and 16-bit register defines..
- */
-#define AL(regs)	(((unsigned char *)&((regs)->pt.eax))[0])
-#define AH(regs)	(((unsigned char *)&((regs)->pt.eax))[1])
-#define IP(regs)	(*(unsigned short *)&((regs)->pt.eip))
-#define SP(regs)	(*(unsigned short *)&((regs)->pt.esp))
-
-/*
- * virtual flags (16 and 32-bit versions)
- */
-#define VFLAGS	(*(unsigned short *)&(current->thread.v86flags))
-#define VEFLAGS	(current->thread.v86flags)
-
-#define set_flags(X,new,mask) \
-((X) = ((X) & ~(mask)) | ((new) & (mask)))
-
-#define SAFE_MASK	(0xDD5)
-#define RETURN_MASK	(0xDFF)
-
-/* convert kernel_vm86_regs to vm86_regs */
-static int copy_vm86_regs_to_user(struct vm86_regs __user *user,
-				  const struct kernel_vm86_regs *regs)
-{
-	int ret = 0;
-
-	/* kernel_vm86_regs is missing xgs, so copy everything up to
-	   (but not including) orig_eax, and then rest including orig_eax. */
-	ret += copy_to_user(user, regs, offsetof(struct kernel_vm86_regs, pt.orig_eax));
-	ret += copy_to_user(&user->orig_eax, &regs->pt.orig_eax,
-			    sizeof(struct kernel_vm86_regs) -
-			    offsetof(struct kernel_vm86_regs, pt.orig_eax));
-
-	return ret;
-}
-
-/* convert vm86_regs to kernel_vm86_regs */
-static int copy_vm86_regs_from_user(struct kernel_vm86_regs *regs,
-				    const struct vm86_regs __user *user,
-				    unsigned extra)
-{
-	int ret = 0;
-
-	/* copy eax-xfs inclusive */
-	ret += copy_from_user(regs, user, offsetof(struct kernel_vm86_regs, pt.orig_eax));
-	/* copy orig_eax-__gsh+extra */
-	ret += copy_from_user(&regs->pt.orig_eax, &user->orig_eax,
-			      sizeof(struct kernel_vm86_regs) -
-			      offsetof(struct kernel_vm86_regs, pt.orig_eax) +
-			      extra);
-	return ret;
-}
-
-struct pt_regs * FASTCALL(save_v86_state(struct kernel_vm86_regs * regs));
-struct pt_regs * fastcall save_v86_state(struct kernel_vm86_regs * regs)
-{
-	struct tss_struct *tss;
-	struct pt_regs *ret;
-	unsigned long tmp;
-
-	/*
-	 * This gets called from entry.S with interrupts disabled, but
-	 * from process context. Enable interrupts here, before trying
-	 * to access user space.
-	 */
-	local_irq_enable();
-
-	if (!current->thread.vm86_info) {
-		printk("no vm86_info: BAD\n");
-		do_exit(SIGSEGV);
-	}
-	set_flags(regs->pt.eflags, VEFLAGS, VIF_MASK | current->thread.v86mask);
-	tmp = copy_vm86_regs_to_user(&current->thread.vm86_info->regs,regs);
-	tmp += put_user(current->thread.screen_bitmap,&current->thread.vm86_info->screen_bitmap);
-	if (tmp) {
-		printk("vm86: could not access userspace vm86_info\n");
-		do_exit(SIGSEGV);
-	}
-
-	tss = &per_cpu(init_tss, get_cpu());
-	current->thread.esp0 = current->thread.saved_esp0;
-	current->thread.sysenter_cs = __KERNEL_CS;
-	load_esp0(tss, &current->thread);
-	current->thread.saved_esp0 = 0;
-	put_cpu();
-
-	ret = KVM86->regs32;
-
-	ret->xfs = current->thread.saved_fs;
-	loadsegment(gs, current->thread.saved_gs);
-
-	return ret;
-}
-
-static void mark_screen_rdonly(struct mm_struct *mm)
-{
-	pgd_t *pgd;
-	pud_t *pud;
-	pmd_t *pmd;
-	pte_t *pte;
-	spinlock_t *ptl;
-	int i;
-
-	pgd = pgd_offset(mm, 0xA0000);
-	if (pgd_none_or_clear_bad(pgd))
-		goto out;
-	pud = pud_offset(pgd, 0xA0000);
-	if (pud_none_or_clear_bad(pud))
-		goto out;
-	pmd = pmd_offset(pud, 0xA0000);
-	if (pmd_none_or_clear_bad(pmd))
-		goto out;
-	pte = pte_offset_map_lock(mm, pmd, 0xA0000, &ptl);
-	for (i = 0; i < 32; i++) {
-		if (pte_present(*pte))
-			set_pte(pte, pte_wrprotect(*pte));
-		pte++;
-	}
-	pte_unmap_unlock(pte, ptl);
-out:
-	flush_tlb();
-}
-
-
-
-static int do_vm86_irq_handling(int subfunction, int irqnumber);
-static void do_sys_vm86(struct kernel_vm86_struct *info, struct task_struct *tsk);
-
-asmlinkage int sys_vm86old(struct pt_regs regs)
-{
-	struct vm86_struct __user *v86 = (struct vm86_struct __user *)regs.ebx;
-	struct kernel_vm86_struct info; /* declare this _on top_,
-					 * this avoids wasting of stack space.
-					 * This remains on the stack until we
-					 * return to 32 bit user space.
-					 */
-	struct task_struct *tsk;
-	int tmp, ret = -EPERM;
-
-	tsk = current;
-	if (tsk->thread.saved_esp0)
-		goto out;
-	tmp = copy_vm86_regs_from_user(&info.regs, &v86->regs,
-				       offsetof(struct kernel_vm86_struct, vm86plus) -
-				       sizeof(info.regs));
-	ret = -EFAULT;
-	if (tmp)
-		goto out;
-	memset(&info.vm86plus, 0, (int)&info.regs32 - (int)&info.vm86plus);
-	info.regs32 = &regs;
-	tsk->thread.vm86_info = v86;
-	do_sys_vm86(&info, tsk);
-	ret = 0;	/* we never return here */
-out:
-	return ret;
-}
-
-
-asmlinkage int sys_vm86(struct pt_regs regs)
-{
-	struct kernel_vm86_struct info; /* declare this _on top_,
-					 * this avoids wasting of stack space.
-					 * This remains on the stack until we
-					 * return to 32 bit user space.
-					 */
-	struct task_struct *tsk;
-	int tmp, ret;
-	struct vm86plus_struct __user *v86;
-
-	tsk = current;
-	switch (regs.ebx) {
-		case VM86_REQUEST_IRQ:
-		case VM86_FREE_IRQ:
-		case VM86_GET_IRQ_BITS:
-		case VM86_GET_AND_RESET_IRQ:
-			ret = do_vm86_irq_handling(regs.ebx, (int)regs.ecx);
-			goto out;
-		case VM86_PLUS_INSTALL_CHECK:
-			/* NOTE: on old vm86 stuff this will return the error
-			   from access_ok(), because the subfunction is
-			   interpreted as (invalid) address to vm86_struct.
-			   So the installation check works.
-			 */
-			ret = 0;
-			goto out;
-	}
-
-	/* we come here only for functions VM86_ENTER, VM86_ENTER_NO_BYPASS */
-	ret = -EPERM;
-	if (tsk->thread.saved_esp0)
-		goto out;
-	v86 = (struct vm86plus_struct __user *)regs.ecx;
-	tmp = copy_vm86_regs_from_user(&info.regs, &v86->regs,
-				       offsetof(struct kernel_vm86_struct, regs32) -
-				       sizeof(info.regs));
-	ret = -EFAULT;
-	if (tmp)
-		goto out;
-	info.regs32 = &regs;
-	info.vm86plus.is_vm86pus = 1;
-	tsk->thread.vm86_info = (struct vm86_struct __user *)v86;
-	do_sys_vm86(&info, tsk);
-	ret = 0;	/* we never return here */
-out:
-	return ret;
-}
-
-
-static void do_sys_vm86(struct kernel_vm86_struct *info, struct task_struct *tsk)
-{
-	struct tss_struct *tss;
-/*
- * make sure the vm86() system call doesn't try to do anything silly
- */
-	info->regs.pt.xds = 0;
-	info->regs.pt.xes = 0;
-	info->regs.pt.xfs = 0;
-
-/* we are clearing gs later just before "jmp resume_userspace",
- * because it is not saved/restored.
- */
-
-/*
- * The eflags register is also special: we cannot trust that the user
- * has set it up safely, so this makes sure interrupt etc flags are
- * inherited from protected mode.
- */
- 	VEFLAGS = info->regs.pt.eflags;
-	info->regs.pt.eflags &= SAFE_MASK;
-	info->regs.pt.eflags |= info->regs32->eflags & ~SAFE_MASK;
-	info->regs.pt.eflags |= VM_MASK;
-
-	switch (info->cpu_type) {
-		case CPU_286:
-			tsk->thread.v86mask = 0;
-			break;
-		case CPU_386:
-			tsk->thread.v86mask = NT_MASK | IOPL_MASK;
-			break;
-		case CPU_486:
-			tsk->thread.v86mask = AC_MASK | NT_MASK | IOPL_MASK;
-			break;
-		default:
-			tsk->thread.v86mask = ID_MASK | AC_MASK | NT_MASK | IOPL_MASK;
-			break;
-	}
-
-/*
- * Save old state, set default return value (%eax) to 0
- */
-	info->regs32->eax = 0;
-	tsk->thread.saved_esp0 = tsk->thread.esp0;
-	tsk->thread.saved_fs = info->regs32->xfs;
-	savesegment(gs, tsk->thread.saved_gs);
-
-	tss = &per_cpu(init_tss, get_cpu());
-	tsk->thread.esp0 = (unsigned long) &info->VM86_TSS_ESP0;
-	if (cpu_has_sep)
-		tsk->thread.sysenter_cs = 0;
-	load_esp0(tss, &tsk->thread);
-	put_cpu();
-
-	tsk->thread.screen_bitmap = info->screen_bitmap;
-	if (info->flags & VM86_SCREEN_BITMAP)
-		mark_screen_rdonly(tsk->mm);
-
-	/*call audit_syscall_exit since we do not exit via the normal paths */
-	if (unlikely(current->audit_context))
-		audit_syscall_exit(AUDITSC_RESULT(0), 0);
-
-	__asm__ __volatile__(
-		"movl %0,%%esp\n\t"
-		"movl %1,%%ebp\n\t"
-		"mov  %2, %%gs\n\t"
-		"jmp resume_userspace"
-		: /* no outputs */
-		:"r" (&info->regs), "r" (task_thread_info(tsk)), "r" (0));
-	/* we never return here */
-}
-
-static inline void return_to_32bit(struct kernel_vm86_regs * regs16, int retval)
-{
-	struct pt_regs * regs32;
-
-	regs32 = save_v86_state(regs16);
-	regs32->eax = retval;
-	__asm__ __volatile__("movl %0,%%esp\n\t"
-		"movl %1,%%ebp\n\t"
-		"jmp resume_userspace"
-		: : "r" (regs32), "r" (current_thread_info()));
-}
-
-static inline void set_IF(struct kernel_vm86_regs * regs)
-{
-	VEFLAGS |= VIF_MASK;
-	if (VEFLAGS & VIP_MASK)
-		return_to_32bit(regs, VM86_STI);
-}
-
-static inline void clear_IF(struct kernel_vm86_regs * regs)
-{
-	VEFLAGS &= ~VIF_MASK;
-}
-
-static inline void clear_TF(struct kernel_vm86_regs * regs)
-{
-	regs->pt.eflags &= ~TF_MASK;
-}
-
-static inline void clear_AC(struct kernel_vm86_regs * regs)
-{
-	regs->pt.eflags &= ~AC_MASK;
-}
-
-/* It is correct to call set_IF(regs) from the set_vflags_*
- * functions. However someone forgot to call clear_IF(regs)
- * in the opposite case.
- * After the command sequence CLI PUSHF STI POPF you should
- * end up with interrups disabled, but you ended up with
- * interrupts enabled.
- *  ( I was testing my own changes, but the only bug I
- *    could find was in a function I had not changed. )
- * [KD]
- */
-
-static inline void set_vflags_long(unsigned long eflags, struct kernel_vm86_regs * regs)
-{
-	set_flags(VEFLAGS, eflags, current->thread.v86mask);
-	set_flags(regs->pt.eflags, eflags, SAFE_MASK);
-	if (eflags & IF_MASK)
-		set_IF(regs);
-	else
-		clear_IF(regs);
-}
-
-static inline void set_vflags_short(unsigned short flags, struct kernel_vm86_regs * regs)
-{
-	set_flags(VFLAGS, flags, current->thread.v86mask);
-	set_flags(regs->pt.eflags, flags, SAFE_MASK);
-	if (flags & IF_MASK)
-		set_IF(regs);
-	else
-		clear_IF(regs);
-}
-
-static inline unsigned long get_vflags(struct kernel_vm86_regs * regs)
-{
-	unsigned long flags = regs->pt.eflags & RETURN_MASK;
-
-	if (VEFLAGS & VIF_MASK)
-		flags |= IF_MASK;
-	flags |= IOPL_MASK;
-	return flags | (VEFLAGS & current->thread.v86mask);
-}
-
-static inline int is_revectored(int nr, struct revectored_struct * bitmap)
-{
-	__asm__ __volatile__("btl %2,%1\n\tsbbl %0,%0"
-		:"=r" (nr)
-		:"m" (*bitmap),"r" (nr));
-	return nr;
-}
-
-#define val_byte(val, n) (((__u8 *)&val)[n])
-
-#define pushb(base, ptr, val, err_label) \
-	do { \
-		__u8 __val = val; \
-		ptr--; \
-		if (put_user(__val, base + ptr) < 0) \
-			goto err_label; \
-	} while(0)
-
-#define pushw(base, ptr, val, err_label) \
-	do { \
-		__u16 __val = val; \
-		ptr--; \
-		if (put_user(val_byte(__val, 1), base + ptr) < 0) \
-			goto err_label; \
-		ptr--; \
-		if (put_user(val_byte(__val, 0), base + ptr) < 0) \
-			goto err_label; \
-	} while(0)
-
-#define pushl(base, ptr, val, err_label) \
-	do { \
-		__u32 __val = val; \
-		ptr--; \
-		if (put_user(val_byte(__val, 3), base + ptr) < 0) \
-			goto err_label; \
-		ptr--; \
-		if (put_user(val_byte(__val, 2), base + ptr) < 0) \
-			goto err_label; \
-		ptr--; \
-		if (put_user(val_byte(__val, 1), base + ptr) < 0) \
-			goto err_label; \
-		ptr--; \
-		if (put_user(val_byte(__val, 0), base + ptr) < 0) \
-			goto err_label; \
-	} while(0)
-
-#define popb(base, ptr, err_label) \
-	({ \
-		__u8 __res; \
-		if (get_user(__res, base + ptr) < 0) \
-			goto err_label; \
-		ptr++; \
-		__res; \
-	})
-
-#define popw(base, ptr, err_label) \
-	({ \
-		__u16 __res; \
-		if (get_user(val_byte(__res, 0), base + ptr) < 0) \
-			goto err_label; \
-		ptr++; \
-		if (get_user(val_byte(__res, 1), base + ptr) < 0) \
-			goto err_label; \
-		ptr++; \
-		__res; \
-	})
-
-#define popl(base, ptr, err_label) \
-	({ \
-		__u32 __res; \
-		if (get_user(val_byte(__res, 0), base + ptr) < 0) \
-			goto err_label; \
-		ptr++; \
-		if (get_user(val_byte(__res, 1), base + ptr) < 0) \
-			goto err_label; \
-		ptr++; \
-		if (get_user(val_byte(__res, 2), base + ptr) < 0) \
-			goto err_label; \
-		ptr++; \
-		if (get_user(val_byte(__res, 3), base + ptr) < 0) \
-			goto err_label; \
-		ptr++; \
-		__res; \
-	})
-
-/* There are so many possible reasons for this function to return
- * VM86_INTx, so adding another doesn't bother me. We can expect
- * userspace programs to be able to handle it. (Getting a problem
- * in userspace is always better than an Oops anyway.) [KD]
- */
-static void do_int(struct kernel_vm86_regs *regs, int i,
-    unsigned char __user * ssp, unsigned short sp)
-{
-	unsigned long __user *intr_ptr;
-	unsigned long segoffs;
-
-	if (regs->pt.xcs == BIOSSEG)
-		goto cannot_handle;
-	if (is_revectored(i, &KVM86->int_revectored))
-		goto cannot_handle;
-	if (i==0x21 && is_revectored(AH(regs),&KVM86->int21_revectored))
-		goto cannot_handle;
-	intr_ptr = (unsigned long __user *) (i << 2);
-	if (get_user(segoffs, intr_ptr))
-		goto cannot_handle;
-	if ((segoffs >> 16) == BIOSSEG)
-		goto cannot_handle;
-	pushw(ssp, sp, get_vflags(regs), cannot_handle);
-	pushw(ssp, sp, regs->pt.xcs, cannot_handle);
-	pushw(ssp, sp, IP(regs), cannot_handle);
-	regs->pt.xcs = segoffs >> 16;
-	SP(regs) -= 6;
-	IP(regs) = segoffs & 0xffff;
-	clear_TF(regs);
-	clear_IF(regs);
-	clear_AC(regs);
-	return;
-
-cannot_handle:
-	return_to_32bit(regs, VM86_INTx + (i << 8));
-}
-
-int handle_vm86_trap(struct kernel_vm86_regs * regs, long error_code, int trapno)
-{
-	if (VMPI.is_vm86pus) {
-		if ( (trapno==3) || (trapno==1) )
-			return_to_32bit(regs, VM86_TRAP + (trapno << 8));
-		do_int(regs, trapno, (unsigned char __user *) (regs->pt.xss << 4), SP(regs));
-		return 0;
-	}
-	if (trapno !=1)
-		return 1; /* we let this handle by the calling routine */
-	if (current->ptrace & PT_PTRACED) {
-		unsigned long flags;
-		spin_lock_irqsave(&current->sighand->siglock, flags);
-		sigdelset(&current->blocked, SIGTRAP);
-		recalc_sigpending();
-		spin_unlock_irqrestore(&current->sighand->siglock, flags);
-	}
-	send_sig(SIGTRAP, current, 1);
-	current->thread.trap_no = trapno;
-	current->thread.error_code = error_code;
-	return 0;
-}
-
-void handle_vm86_fault(struct kernel_vm86_regs * regs, long error_code)
-{
-	unsigned char opcode;
-	unsigned char __user *csp;
-	unsigned char __user *ssp;
-	unsigned short ip, sp, orig_flags;
-	int data32, pref_done;
-
-#define CHECK_IF_IN_TRAP \
-	if (VMPI.vm86dbg_active && VMPI.vm86dbg_TFpendig) \
-		newflags |= TF_MASK
-#define VM86_FAULT_RETURN do { \
-	if (VMPI.force_return_for_pic  && (VEFLAGS & (IF_MASK | VIF_MASK))) \
-		return_to_32bit(regs, VM86_PICRETURN); \
-	if (orig_flags & TF_MASK) \
-		handle_vm86_trap(regs, 0, 1); \
-	return; } while (0)
-
-	orig_flags = *(unsigned short *)&regs->pt.eflags;
-
-	csp = (unsigned char __user *) (regs->pt.xcs << 4);
-	ssp = (unsigned char __user *) (regs->pt.xss << 4);
-	sp = SP(regs);
-	ip = IP(regs);
-
-	data32 = 0;
-	pref_done = 0;
-	do {
-		switch (opcode = popb(csp, ip, simulate_sigsegv)) {
-			case 0x66:      /* 32-bit data */     data32=1; break;
-			case 0x67:      /* 32-bit address */  break;
-			case 0x2e:      /* CS */              break;
-			case 0x3e:      /* DS */              break;
-			case 0x26:      /* ES */              break;
-			case 0x36:      /* SS */              break;
-			case 0x65:      /* GS */              break;
-			case 0x64:      /* FS */              break;
-			case 0xf2:      /* repnz */       break;
-			case 0xf3:      /* rep */             break;
-			default: pref_done = 1;
-		}
-	} while (!pref_done);
-
-	switch (opcode) {
-
-	/* pushf */
-	case 0x9c:
-		if (data32) {
-			pushl(ssp, sp, get_vflags(regs), simulate_sigsegv);
-			SP(regs) -= 4;
-		} else {
-			pushw(ssp, sp, get_vflags(regs), simulate_sigsegv);
-			SP(regs) -= 2;
-		}
-		IP(regs) = ip;
-		VM86_FAULT_RETURN;
-
-	/* popf */
-	case 0x9d:
-		{
-		unsigned long newflags;
-		if (data32) {
-			newflags=popl(ssp, sp, simulate_sigsegv);
-			SP(regs) += 4;
-		} else {
-			newflags = popw(ssp, sp, simulate_sigsegv);
-			SP(regs) += 2;
-		}
-		IP(regs) = ip;
-		CHECK_IF_IN_TRAP;
-		if (data32) {
-			set_vflags_long(newflags, regs);
-		} else {
-			set_vflags_short(newflags, regs);
-		}
-		VM86_FAULT_RETURN;
-		}
-
-	/* int xx */
-	case 0xcd: {
-		int intno=popb(csp, ip, simulate_sigsegv);
-		IP(regs) = ip;
-		if (VMPI.vm86dbg_active) {
-			if ( (1 << (intno &7)) & VMPI.vm86dbg_intxxtab[intno >> 3] )
-				return_to_32bit(regs, VM86_INTx + (intno << 8));
-		}
-		do_int(regs, intno, ssp, sp);
-		return;
-	}
-
-	/* iret */
-	case 0xcf:
-		{
-		unsigned long newip;
-		unsigned long newcs;
-		unsigned long newflags;
-		if (data32) {
-			newip=popl(ssp, sp, simulate_sigsegv);
-			newcs=popl(ssp, sp, simulate_sigsegv);
-			newflags=popl(ssp, sp, simulate_sigsegv);
-			SP(regs) += 12;
-		} else {
-			newip = popw(ssp, sp, simulate_sigsegv);
-			newcs = popw(ssp, sp, simulate_sigsegv);
-			newflags = popw(ssp, sp, simulate_sigsegv);
-			SP(regs) += 6;
-		}
-		IP(regs) = newip;
-		regs->pt.xcs = newcs;
-		CHECK_IF_IN_TRAP;
-		if (data32) {
-			set_vflags_long(newflags, regs);
-		} else {
-			set_vflags_short(newflags, regs);
-		}
-		VM86_FAULT_RETURN;
-		}
-
-	/* cli */
-	case 0xfa:
-		IP(regs) = ip;
-		clear_IF(regs);
-		VM86_FAULT_RETURN;
-
-	/* sti */
-	/*
-	 * Damn. This is incorrect: the 'sti' instruction should actually
-	 * enable interrupts after the /next/ instruction. Not good.
-	 *
-	 * Probably needs some horsing around with the TF flag. Aiee..
-	 */
-	case 0xfb:
-		IP(regs) = ip;
-		set_IF(regs);
-		VM86_FAULT_RETURN;
-
-	default:
-		return_to_32bit(regs, VM86_UNKNOWN);
-	}
-
-	return;
-
-simulate_sigsegv:
-	/* FIXME: After a long discussion with Stas we finally
-	 *        agreed, that this is wrong. Here we should
-	 *        really send a SIGSEGV to the user program.
-	 *        But how do we create the correct context? We
-	 *        are inside a general protection fault handler
-	 *        and has just returned from a page fault handler.
-	 *        The correct context for the signal handler
-	 *        should be a mixture of the two, but how do we
-	 *        get the information? [KD]
-	 */
-	return_to_32bit(regs, VM86_UNKNOWN);
-}
-
-/* ---------------- vm86 special IRQ passing stuff ----------------- */
-
-#define VM86_IRQNAME		"vm86irq"
-
-static struct vm86_irqs {
-	struct task_struct *tsk;
-	int sig;
-} vm86_irqs[16];
-
-static DEFINE_SPINLOCK(irqbits_lock);
-static int irqbits;
-
-#define ALLOWED_SIGS ( 1 /* 0 = don't send a signal */ \
-	| (1 << SIGUSR1) | (1 << SIGUSR2) | (1 << SIGIO)  | (1 << SIGURG) \
-	| (1 << SIGUNUSED) )
-	
-static irqreturn_t irq_handler(int intno, void *dev_id)
-{
-	int irq_bit;
-	unsigned long flags;
-
-	spin_lock_irqsave(&irqbits_lock, flags);	
-	irq_bit = 1 << intno;
-	if ((irqbits & irq_bit) || ! vm86_irqs[intno].tsk)
-		goto out;
-	irqbits |= irq_bit;
-	if (vm86_irqs[intno].sig)
-		send_sig(vm86_irqs[intno].sig, vm86_irqs[intno].tsk, 1);
-	/*
-	 * IRQ will be re-enabled when user asks for the irq (whether
-	 * polling or as a result of the signal)
-	 */
-	disable_irq_nosync(intno);
-	spin_unlock_irqrestore(&irqbits_lock, flags);
-	return IRQ_HANDLED;
-
-out:
-	spin_unlock_irqrestore(&irqbits_lock, flags);	
-	return IRQ_NONE;
-}
-
-static inline void free_vm86_irq(int irqnumber)
-{
-	unsigned long flags;
-
-	free_irq(irqnumber, NULL);
-	vm86_irqs[irqnumber].tsk = NULL;
-
-	spin_lock_irqsave(&irqbits_lock, flags);	
-	irqbits &= ~(1 << irqnumber);
-	spin_unlock_irqrestore(&irqbits_lock, flags);	
-}
-
-void release_vm86_irqs(struct task_struct *task)
-{
-	int i;
-	for (i = FIRST_VM86_IRQ ; i <= LAST_VM86_IRQ; i++)
-	    if (vm86_irqs[i].tsk == task)
-		free_vm86_irq(i);
-}
-
-static inline int get_and_reset_irq(int irqnumber)
-{
-	int bit;
-	unsigned long flags;
-	int ret = 0;
-	
-	if (invalid_vm86_irq(irqnumber)) return 0;
-	if (vm86_irqs[irqnumber].tsk != current) return 0;
-	spin_lock_irqsave(&irqbits_lock, flags);	
-	bit = irqbits & (1 << irqnumber);
-	irqbits &= ~bit;
-	if (bit) {
-		enable_irq(irqnumber);
-		ret = 1;
-	}
-
-	spin_unlock_irqrestore(&irqbits_lock, flags);	
-	return ret;
-}
-
-
-static int do_vm86_irq_handling(int subfunction, int irqnumber)
-{
-	int ret;
-	switch (subfunction) {
-		case VM86_GET_AND_RESET_IRQ: {
-			return get_and_reset_irq(irqnumber);
-		}
-		case VM86_GET_IRQ_BITS: {
-			return irqbits;
-		}
-		case VM86_REQUEST_IRQ: {
-			int sig = irqnumber >> 8;
-			int irq = irqnumber & 255;
-			if (!capable(CAP_SYS_ADMIN)) return -EPERM;
-			if (!((1 << sig) & ALLOWED_SIGS)) return -EPERM;
-			if (invalid_vm86_irq(irq)) return -EPERM;
-			if (vm86_irqs[irq].tsk) return -EPERM;
-			ret = request_irq(irq, &irq_handler, 0, VM86_IRQNAME, NULL);
-			if (ret) return ret;
-			vm86_irqs[irq].sig = sig;
-			vm86_irqs[irq].tsk = current;
-			return irq;
-		}
-		case  VM86_FREE_IRQ: {
-			if (invalid_vm86_irq(irqnumber)) return -EPERM;
-			if (!vm86_irqs[irqnumber].tsk) return 0;
-			if (vm86_irqs[irqnumber].tsk != current) return -EPERM;
-			free_vm86_irq(irqnumber);
-			return 0;
-		}
-	}
-	return -EINVAL;
-}
-