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
  17 struct 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
  31 struct 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
  63 void handle_vm86_fault(struct kernel_vm86_regs *, long);
  64 int handle_vm86_trap(struct kernel_vm86_regs *, long, int);
  65 struct pt_regs *save_v86_state(struct kernel_vm86_regs *);
  66
  67 struct task_struct;
  68 void release_vm86_irqs(struct task_struct *);
  69
  70 #else
  71
  72 #define handle_vm86_fault(a, b)
  73 #define release_vm86_irqs(a)
  74
  75 static 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 */