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Commit d4ce0f26 authored by Brian Gerst's avatar Brian Gerst Committed by Ingo Molnar
Browse files

x86/vm86: Move fields from 'struct kernel_vm86_struct' to 'struct vm86' 



Move the non-regs fields to the off-stack data.

Signed-off-by: default avatarBrian Gerst <brgerst@gmail.com>
Acked-by: default avatarAndy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1438148483-11932-3-git-send-email-brgerst@gmail.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 9fda6a06

arch/x86/include/asm/vm86.h

+8 −8
Original line number Diff line number Diff line
@@ -37,13 +37,7 @@ struct kernel_vm86_struct { 
 * Therefore, pt_regs in fact points to a complete 'kernel_vm86_struct'

 * in kernelspace, hence we need not reget the data from userspace.

 */

#define VM86_TSS_ESP0 flags

	unsigned long flags;

	unsigned long screen_bitmap;

	unsigned long cpu_type;

	struct revectored_struct int_revectored;

	struct revectored_struct int21_revectored;

	struct vm86plus_info_struct vm86plus;

#define VM86_TSS_ESP0 regs32

	struct pt_regs *regs32;   /* here we save the pointer to the old regs */

/*

 * The below is not part of the structure, but the stack layout continues
@@ -59,10 +53,16 @@ struct kernel_vm86_struct { 


struct vm86 {

	struct vm86plus_struct __user *vm86_info;

	unsigned long screen_bitmap;

	unsigned long v86flags;

	unsigned long v86mask;

	unsigned long saved_sp0;



	unsigned long flags;

	unsigned long screen_bitmap;

	unsigned long cpu_type;

	struct revectored_struct int_revectored;

	struct revectored_struct int21_revectored;

	struct vm86plus_info_struct vm86plus;

};



#ifdef CONFIG_VM86

arch/x86/kernel/vm86_32.c

+22 −20
Original line number Diff line number Diff line
@@ -68,7 +68,6 @@ 




#define KVM86	((struct kernel_vm86_struct *)regs)

#define VMPI	KVM86->vm86plus





/*
@@ -114,7 +113,7 @@ struct pt_regs *save_v86_state(struct kernel_vm86_regs *regs) 
	set_flags(regs->pt.flags, VEFLAGS, X86_EFLAGS_VIF | vm86->v86mask);

	user = vm86->vm86_info;



	if (!access_ok(VERIFY_WRITE, user, VMPI.is_vm86pus ?

	if (!access_ok(VERIFY_WRITE, user, vm86->vm86plus.is_vm86pus ?

		       sizeof(struct vm86plus_struct) :

		       sizeof(struct vm86_struct))) {

		pr_alert("could not access userspace vm86_info\n");
@@ -282,25 +281,27 @@ static long do_sys_vm86(struct vm86plus_struct __user *v86, bool plus, 
		get_user_ex(info->regs.fs, &v86->regs.fs);

		get_user_ex(info->regs.gs, &v86->regs.gs);



		get_user_ex(info->flags, &v86->flags);

		get_user_ex(info->screen_bitmap, &v86->screen_bitmap);

		get_user_ex(info->cpu_type, &v86->cpu_type);

		get_user_ex(vm86->flags, &v86->flags);

		get_user_ex(vm86->screen_bitmap, &v86->screen_bitmap);

		get_user_ex(vm86->cpu_type, &v86->cpu_type);

	} get_user_catch(err);

	if (err)

		return err;



	if (copy_from_user(&info->int_revectored, &v86->int_revectored,

	if (copy_from_user(&vm86->int_revectored, &v86->int_revectored,

			   sizeof(struct revectored_struct)))

		return -EFAULT;

	if (copy_from_user(&info->int21_revectored, &v86->int21_revectored,

	if (copy_from_user(&vm86->int21_revectored, &v86->int21_revectored,

			   sizeof(struct revectored_struct)))

		return -EFAULT;

	if (plus) {

		if (copy_from_user(&info->vm86plus, &v86->vm86plus,

		if (copy_from_user(&vm86->vm86plus, &v86->vm86plus,

				   sizeof(struct vm86plus_info_struct)))

			return -EFAULT;

		info->vm86plus.is_vm86pus = 1;

	}

		vm86->vm86plus.is_vm86pus = 1;

	} else

		memset(&vm86->vm86plus, 0,

		       sizeof(struct vm86plus_info_struct));



	info->regs32 = current_pt_regs();

	vm86->vm86_info = v86;
@@ -317,7 +318,7 @@ static long do_sys_vm86(struct vm86plus_struct __user *v86, bool plus, 


	info->regs.pt.orig_ax = info->regs32->orig_ax;



	switch (info->cpu_type) {

	switch (vm86->cpu_type) {

	case CPU_286:

		vm86->v86mask = 0;

		break;
@@ -346,8 +347,7 @@ static long do_sys_vm86(struct vm86plus_struct __user *v86, bool plus, 
	load_sp0(tss, &tsk->thread);

	put_cpu();



	vm86->screen_bitmap = info->screen_bitmap;

	if (info->flags & VM86_SCREEN_BITMAP)

	if (vm86->flags & VM86_SCREEN_BITMAP)

		mark_screen_rdonly(tsk->mm);



	/*call __audit_syscall_exit since we do not exit via the normal paths */
@@ -539,12 +539,13 @@ static void do_int(struct kernel_vm86_regs *regs, int i, 
{

	unsigned long __user *intr_ptr;

	unsigned long segoffs;

	struct kernel_vm86_info *vm86 = current->thread.vm86;



	if (regs->pt.cs == BIOSSEG)

		goto cannot_handle;

	if (is_revectored(i, &KVM86->int_revectored))

	if (is_revectored(i, &vm86->int_revectored))

		goto cannot_handle;

	if (i == 0x21 && is_revectored(AH(regs), &KVM86->int21_revectored))

	if (i == 0x21 && is_revectored(AH(regs), &vm86->int21_revectored))

		goto cannot_handle;

	intr_ptr = (unsigned long __user *) (i << 2);

	if (get_user(segoffs, intr_ptr))
@@ -568,7 +569,7 @@ static void do_int(struct kernel_vm86_regs *regs, int i, 


int handle_vm86_trap(struct kernel_vm86_regs *regs, long error_code, int trapno)

{

	if (VMPI.is_vm86pus) {

	if (current->thread.vm86->vm86plus.is_vm86pus) {

		if ((trapno == 3) || (trapno == 1)) {

			KVM86->regs32->ax = VM86_TRAP + (trapno << 8);

			/* setting this flag forces the code in entry_32.S to
@@ -595,12 +596,13 @@ void handle_vm86_fault(struct kernel_vm86_regs *regs, long error_code) 
	unsigned char __user *ssp;

	unsigned short ip, sp, orig_flags;

	int data32, pref_done;

	struct vm86plus_info_struct *vmpi = &current->thread.vm86->vm86plus;



#define CHECK_IF_IN_TRAP \

	if (VMPI.vm86dbg_active && VMPI.vm86dbg_TFpendig) \

	if (vmpi->vm86dbg_active && vmpi->vm86dbg_TFpendig) \

		newflags |= X86_EFLAGS_TF

#define VM86_FAULT_RETURN do { \

	if (VMPI.force_return_for_pic  && (VEFLAGS & (X86_EFLAGS_IF | X86_EFLAGS_VIF))) \

	if (vmpi->force_return_for_pic  && (VEFLAGS & (X86_EFLAGS_IF | X86_EFLAGS_VIF))) \

		return_to_32bit(regs, VM86_PICRETURN); \

	if (orig_flags & X86_EFLAGS_TF) \

		handle_vm86_trap(regs, 0, 1); \
@@ -670,8 +672,8 @@ void handle_vm86_fault(struct kernel_vm86_regs *regs, long error_code) 
	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])

		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);