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#ifndef _LINUX_VM86_H

#define _LINUX_VM86_H

/*

 * I'm guessing at the VIF/VIP flag usage, but hope that this is how

 * the Pentium uses them. Linux will return from vm86 mode when both

 * VIF and VIP is set.

 *

 * On a Pentium, we could probably optimize the virtual flags directly

 * in the eflags register instead of doing it "by hand" in vflags...

 *

 * Linus

 */

#define TF_MASK         0x00000100

#define IF_MASK         0x00000200

#define IOPL_MASK       0x00003000

#define NT_MASK         0x00004000

#define VM_MASK         0x00020000

#define AC_MASK         0x00040000

#define VIF_MASK        0x00080000      /* virtual interrupt flag */

#define VIP_MASK        0x00100000      /* virtual interrupt pending */

#define ID_MASK         0x00200000

#define BIOSSEG         0x0f000

#define CPU_086         0

#define CPU_186         1

#define CPU_286         2

#define CPU_386         3

#define CPU_486         4

#define CPU_586         5

/*

 * Return values for the 'vm86()' system call

 */

#define VM86_TYPE(retval)       ((retval) & 0xff)

#define VM86_ARG(retval)        ((retval) >> 8)

#define VM86_SIGNAL     0        /* return due to signal */

#define VM86_UNKNOWN    1       /* unhandled GP fault - IO-instruction or similar */

#define VM86_INTx       2       /* int3/int x instruction (ARG = x) */

#define VM86_STI        3       /* sti/popf/iret instruction enabled virtual interrupts */

/*

 * Additional return values when invoking new vm86()

 */

#define VM86_PICRETURN  4       /* return due to pending PIC request */

#define VM86_TRAP       6       /* return due to DOS-debugger request */

/*

 * function codes when invoking new vm86()

 */

#define VM86_PLUS_INSTALL_CHECK 0

#define VM86_ENTER              1

#define VM86_ENTER_NO_BYPASS    2

#define VM86_REQUEST_IRQ        3

#define VM86_FREE_IRQ           4

#define VM86_GET_IRQ_BITS       5

#define VM86_GET_AND_RESET_IRQ  6

/*

 * This is the stack-layout when we have done a "SAVE_ALL" from vm86

 * mode - the main change is that the old segment descriptors aren't

 * useful any more and are forced to be zero by the kernel (and the

 * hardware when a trap occurs), and the real segment descriptors are

 * at the end of the structure. Look at ptrace.h to see the "normal"

 * setup.

 */

struct vm86_regs {

/*

 * normal regs, with special meaning for the segment descriptors..

 */

        long ebx;

        long ecx;

        long edx;

        long esi;

        long edi;

        long ebp;

        long eax;

        long __null_ds;

        long __null_es;

        long __null_fs;

        long __null_gs;

        long orig_eax;

        long eip;

        unsigned short cs, __csh;

        long eflags;

        long esp;

        unsigned short ss, __ssh;

/*

 * these are specific to v86 mode:

 */

        unsigned short es, __esh;

        unsigned short ds, __dsh;

        unsigned short fs, __fsh;

        unsigned short gs, __gsh;

};

struct revectored_struct {

        unsigned long __map[8];                 /* 256 bits */

};

struct vm86_struct {

        struct vm86_regs regs;

        unsigned long flags;

        unsigned long screen_bitmap;

        unsigned long cpu_type;

        struct revectored_struct int_revectored;

        struct revectored_struct int21_revectored;

};

/*

 * flags masks

 */

#define VM86_SCREEN_BITMAP      0x0001

struct vm86plus_info_struct {

        unsigned long force_return_for_pic:1;

        unsigned long vm86dbg_active:1;       /* for debugger */

        unsigned long vm86dbg_TFpendig:1;     /* for debugger */

        unsigned long unused:28;

        unsigned long is_vm86pus:1;           /* for vm86 internal use */

        unsigned char vm86dbg_intxxtab[32];   /* for debugger */

};

struct vm86plus_struct {

        struct vm86_regs regs;

        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 __KERNEL__

struct kernel_vm86_struct {

        struct vm86_regs regs;

/*

 * the below part remains on the kernel stack while we are in VM86 mode.

 * 'tss.esp0' then contains the address of VM86_TSS_ESP0 below, and when we

 * get forced back from VM86, the CPU and "SAVE_ALL" will restore the above

 * 'struct kernel_vm86_regs' with the then actual values.

 * 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;

        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

 * this way. In front of 'return-eip' may be some data, depending on

 * compilation, so we don't rely on this and save the pointer to 'oldregs'

 * in 'regs32' above.

 * However, with GCC-2.7.2 and the current CFLAGS you see exactly this:

        long return-eip;        from call to vm86()

        struct pt_regs oldregs;  user space registers as saved by syscall

 */

};

void handle_vm86_fault(struct vm86_regs *, long);

int handle_vm86_trap(struct vm86_regs *, long, int);

#endif /* __KERNEL__ */

#endif