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422 giacomo 1
#ifndef _LINUX_VM86_H
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#define _LINUX_VM86_H
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/*
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 * I'm guessing at the VIF/VIP flag usage, but hope that this is how
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 * the Pentium uses them. Linux will return from vm86 mode when both
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 * VIF and VIP is set.
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 *
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 * On a Pentium, we could probably optimize the virtual flags directly
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 * in the eflags register instead of doing it "by hand" in vflags...
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 *
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 * Linus
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 */
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#define TF_MASK         0x00000100
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#define IF_MASK         0x00000200
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#define IOPL_MASK       0x00003000
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#define NT_MASK         0x00004000
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#define VM_MASK         0x00020000
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#define AC_MASK         0x00040000
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#define VIF_MASK        0x00080000      /* virtual interrupt flag */
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#define VIP_MASK        0x00100000      /* virtual interrupt pending */
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#define ID_MASK         0x00200000
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#define BIOSSEG         0x0f000
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#define CPU_086         0
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#define CPU_186         1
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#define CPU_286         2
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#define CPU_386         3
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#define CPU_486         4
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#define CPU_586         5
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/*
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 * Return values for the 'vm86()' system call
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 */
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#define VM86_TYPE(retval)       ((retval) & 0xff)
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#define VM86_ARG(retval)        ((retval) >> 8)
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#define VM86_SIGNAL     0       /* return due to signal */
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#define VM86_UNKNOWN    1       /* unhandled GP fault - IO-instruction or similar */
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#define VM86_INTx       2       /* int3/int x instruction (ARG = x) */
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#define VM86_STI        3       /* sti/popf/iret instruction enabled virtual interrupts */
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/*
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 * Additional return values when invoking new vm86()
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 */
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#define VM86_PICRETURN  4       /* return due to pending PIC request */
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#define VM86_TRAP       6       /* return due to DOS-debugger request */
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/*
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 * function codes when invoking new vm86()
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 */
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#define VM86_PLUS_INSTALL_CHECK 0
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#define VM86_ENTER              1
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#define VM86_ENTER_NO_BYPASS    2
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#define VM86_REQUEST_IRQ        3
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#define VM86_FREE_IRQ           4
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#define VM86_GET_IRQ_BITS       5
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#define VM86_GET_AND_RESET_IRQ  6
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/*
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 * This is the stack-layout seen by the user space program when we have
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 * done a translation of "SAVE_ALL" from vm86 mode. The real kernel layout
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 * is 'kernel_vm86_regs' (see below).
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 */
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struct vm86_regs {
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/*
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 * normal regs, with special meaning for the segment descriptors..
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 */
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        long ebx;
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        long ecx;
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        long edx;
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        long esi;
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        long edi;
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        long ebp;
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        long eax;
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        long __null_ds;
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        long __null_es;
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        long __null_fs;
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        long __null_gs;
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        long orig_eax;
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        long eip;
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        unsigned short cs, __csh;
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        long eflags;
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        long esp;
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        unsigned short ss, __ssh;
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/*
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 * these are specific to v86 mode:
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 */
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        unsigned short es, __esh;
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        unsigned short ds, __dsh;
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        unsigned short fs, __fsh;
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        unsigned short gs, __gsh;
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};
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struct revectored_struct {
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        unsigned long __map[8];                 /* 256 bits */
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};
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struct vm86_struct {
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        struct vm86_regs regs;
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        unsigned long flags;
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        unsigned long screen_bitmap;
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        unsigned long cpu_type;
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        struct revectored_struct int_revectored;
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        struct revectored_struct int21_revectored;
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};
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/*
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 * flags masks
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 */
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#define VM86_SCREEN_BITMAP      0x0001
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struct vm86plus_info_struct {
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        unsigned long force_return_for_pic:1;
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        unsigned long vm86dbg_active:1;       /* for debugger */
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        unsigned long vm86dbg_TFpendig:1;     /* for debugger */
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        unsigned long unused:28;
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        unsigned long is_vm86pus:1;           /* for vm86 internal use */
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        unsigned char vm86dbg_intxxtab[32];   /* for debugger */
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};
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struct vm86plus_struct {
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        struct vm86_regs regs;
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        unsigned long flags;
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        unsigned long screen_bitmap;
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        unsigned long cpu_type;
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        struct revectored_struct int_revectored;
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        struct revectored_struct int21_revectored;
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        struct vm86plus_info_struct vm86plus;
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};
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#ifdef __KERNEL__
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/*
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 * This is the (kernel) stack-layout when we have done a "SAVE_ALL" from vm86
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 * mode - the main change is that the old segment descriptors aren't
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 * useful any more and are forced to be zero by the kernel (and the
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 * hardware when a trap occurs), and the real segment descriptors are
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 * at the end of the structure. Look at ptrace.h to see the "normal"
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 * setup. For user space layout see 'struct vm86_regs' above.
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 */
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struct kernel_vm86_regs {
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/*
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 * normal regs, with special meaning for the segment descriptors..
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 */
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        long ebx;
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        long ecx;
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        long edx;
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        long esi;
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        long edi;
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        long ebp;
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        long eax;
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        long __null_ds;
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        long __null_es;
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        long orig_eax;
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        long eip;
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        unsigned short cs, __csh;
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        long eflags;
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        long esp;
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        unsigned short ss, __ssh;
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/*
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 * these are specific to v86 mode:
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 */
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        unsigned short es, __esh;
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        unsigned short ds, __dsh;
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        unsigned short fs, __fsh;
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        unsigned short gs, __gsh;
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};
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struct kernel_vm86_struct {
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        struct kernel_vm86_regs regs;
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/*
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 * the below part remains on the kernel stack while we are in VM86 mode.
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 * 'tss.esp0' then contains the address of VM86_TSS_ESP0 below, and when we
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 * get forced back from VM86, the CPU and "SAVE_ALL" will restore the above
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 * 'struct kernel_vm86_regs' with the then actual values.
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 * Therefore, pt_regs in fact points to a complete 'kernel_vm86_struct'
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 * in kernelspace, hence we need not reget the data from userspace.
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 */
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#define VM86_TSS_ESP0 flags
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        unsigned long flags;
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        unsigned long screen_bitmap;
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        unsigned long cpu_type;
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        struct revectored_struct int_revectored;
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        struct revectored_struct int21_revectored;
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        struct vm86plus_info_struct vm86plus;
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        struct pt_regs *regs32;   /* here we save the pointer to the old regs */
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/*
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 * The below is not part of the structure, but the stack layout continues
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 * this way. In front of 'return-eip' may be some data, depending on
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 * compilation, so we don't rely on this and save the pointer to 'oldregs'
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 * in 'regs32' above.
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 * However, with GCC-2.7.2 and the current CFLAGS you see exactly this:
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        long return-eip;        from call to vm86()
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        struct pt_regs oldregs;  user space registers as saved by syscall
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 */
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};
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void handle_vm86_fault(struct kernel_vm86_regs *, long);
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int handle_vm86_trap(struct kernel_vm86_regs *, long, int);
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#endif /* __KERNEL__ */
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#endif