LXR linux/arch/x86/include/asm/vm86.h

   1#ifndef _ASM_X86_VM86_H
   2#define _ASM_X86_VM86_H
   3
   4
   5#include <asm/ptrace.h>
   6#include <uapi/asm/vm86.h>
   7
   8/*
   9 * This is the (kernel) stack-layout when we have done a "SAVE_ALL" from vm86
  10 * mode - the main change is that the old segment descriptors aren't
  11 * useful any more and are forced to be zero by the kernel (and the
  12 * hardware when a trap occurs), and the real segment descriptors are
  13 * at the end of the structure. Look at ptrace.h to see the "normal"
  14 * setup. For user space layout see 'struct vm86_regs' above.
  15 */
  16
  17struct kernel_vm86_regs {
  18/*
  19 * normal regs, with special meaning for the segment descriptors..
  20 */
  21        struct pt_regs pt;
  22/*
  23 * these are specific to v86 mode:
  24 */
  25        unsigned short es, __esh;
  26        unsigned short ds, __dsh;
  27        unsigned short fs, __fsh;
  28        unsigned short gs, __gsh;
  29};
  30
  31struct kernel_vm86_struct {
  32        struct kernel_vm86_regs regs;
  33/*
  34 * the below part remains on the kernel stack while we are in VM86 mode.
  35 * 'tss.esp0' then contains the address of VM86_TSS_ESP0 below, and when we
  36 * get forced back from VM86, the CPU and "SAVE_ALL" will restore the above
  37 * 'struct kernel_vm86_regs' with the then actual values.
  38 * Therefore, pt_regs in fact points to a complete 'kernel_vm86_struct'
  39 * in kernelspace, hence we need not reget the data from userspace.
  40 */
  41#define VM86_TSS_ESP0 flags
  42        unsigned long flags;
  43        unsigned long screen_bitmap;
  44        unsigned long cpu_type;
  45        struct revectored_struct int_revectored;
  46        struct revectored_struct int21_revectored;
  47        struct vm86plus_info_struct vm86plus;
  48        struct pt_regs *regs32;   /* here we save the pointer to the old regs */
  49/*
  50 * The below is not part of the structure, but the stack layout continues
  51 * this way. In front of 'return-eip' may be some data, depending on
  52 * compilation, so we don't rely on this and save the pointer to 'oldregs'
  53 * in 'regs32' above.
  54 * However, with GCC-2.7.2 and the current CFLAGS you see exactly this:
  55
  56        long return-eip;        from call to vm86()
  57        struct pt_regs oldregs;  user space registers as saved by syscall
  58 */
  59};
  60
  61#ifdef CONFIG_VM86
  62
  63void handle_vm86_fault(struct kernel_vm86_regs *, long);
  64int handle_vm86_trap(struct kernel_vm86_regs *, long, int);
  65struct pt_regs *save_v86_state(struct kernel_vm86_regs *);
  66
  67struct task_struct;
  68void release_vm86_irqs(struct task_struct *);
  69
  70#else
  71
  72#define handle_vm86_fault(a, b)
  73#define release_vm86_irqs(a)
  74
  75static inline int handle_vm86_trap(struct kernel_vm86_regs *a, long b, int c)
  76{
  77        return 0;
  78}
  79
  80#endif /* CONFIG_VM86 */
  81
  82#endif /* _ASM_X86_VM86_H */
  83