include/asm-i386/vm86.h

   1 #ifndef _LINUX_VM86_H
   2 #define _LINUX_VM86_H
   3
   4 /*
   5  * I'm guessing at the VIF/VIP flag usage, but hope that this is how
   6  * the Pentium uses them. Linux will return from vm86 mode when both
   7  * VIF and VIP is set.
   8  *
   9  * On a Pentium, we could probably optimize the virtual flags directly
  10  * in the eflags register instead of doing it "by hand" in vflags...
  11  *
  12  * Linus
  13  */
  14
  15 #define TF_MASK         0x00000100
  16 #define IF_MASK         0x00000200
  17 #define IOPL_MASK       0x00003000
  18 #define NT_MASK         0x00004000
  19 #ifdef CONFIG_VM86
  20 #define VM_MASK         0x00020000
  21 #else
  22 #define VM_MASK         0 /* ignored */
  23 #endif
  24 #define AC_MASK         0x00040000
  25 #define VIF_MASK        0x00080000      /* virtual interrupt flag */
  26 #define VIP_MASK        0x00100000      /* virtual interrupt pending */
  27 #define ID_MASK         0x00200000
  28
  29 #define BIOSSEG         0x0f000
  30
  31 #define CPU_086         0
  32 #define CPU_186         1
  33 #define CPU_286         2
  34 #define CPU_386         3
  35 #define CPU_486         4
  36 #define CPU_586         5
  37
  38 /*
  39  * Return values for the 'vm86()' system call
  40  */
  41 #define VM86_TYPE(retval)       ((retval) & 0xff)
  42 #define VM86_ARG(retval)        ((retval) >> 8)
  43
  44 #define VM86_SIGNAL     0       /* return due to signal */
  45 #define VM86_UNKNOWN    1       /* unhandled GP fault - IO-instruction or similar */
  46 #define VM86_INTx       2       /* int3/int x instruction (ARG = x) */
  47 #define VM86_STI        3       /* sti/popf/iret instruction enabled virtual interrupts */
  48
  49 /*
  50  * Additional return values when invoking new vm86()
  51  */
  52 #define VM86_PICRETURN  4       /* return due to pending PIC request */
  53 #define VM86_TRAP       6       /* return due to DOS-debugger request */
  54
  55 /*
  56  * function codes when invoking new vm86()
  57  */
  58 #define VM86_PLUS_INSTALL_CHECK 0
  59 #define VM86_ENTER              1
  60 #define VM86_ENTER_NO_BYPASS    2
  61 #define VM86_REQUEST_IRQ        3
  62 #define VM86_FREE_IRQ           4
  63 #define VM86_GET_IRQ_BITS       5
  64 #define VM86_GET_AND_RESET_IRQ  6
  65
  66 /*
  67  * This is the stack-layout seen by the user space program when we have
  68  * done a translation of "SAVE_ALL" from vm86 mode. The real kernel layout
  69  * is 'kernel_vm86_regs' (see below).
  70  */
  71
  72 struct vm86_regs {
  73 /*
  74  * normal regs, with special meaning for the segment descriptors..
  75  */
  76         long ebx;
  77         long ecx;
  78         long edx;
  79         long esi;
  80         long edi;
  81         long ebp;
  82         long eax;
  83         long __null_ds;
  84         long __null_es;
  85         long __null_fs;
  86         long __null_gs;
  87         long orig_eax;
  88         long eip;
  89         unsigned short cs, __csh;
  90         long eflags;
  91         long esp;
  92         unsigned short ss, __ssh;
  93 /*
  94  * these are specific to v86 mode:
  95  */
  96         unsigned short es, __esh;
  97         unsigned short ds, __dsh;
  98         unsigned short fs, __fsh;
  99         unsigned short gs, __gsh;
 100 };
 101
 102 struct revectored_struct {
 103         unsigned long __map[8];                 /* 256 bits */
 104 };
 105
 106 struct vm86_struct {
 107         struct vm86_regs regs;
 108         unsigned long flags;
 109         unsigned long screen_bitmap;
 110         unsigned long cpu_type;
 111         struct revectored_struct int_revectored;
 112         struct revectored_struct int21_revectored;
 113 };
 114
 115 /*
 116  * flags masks
 117  */
 118 #define VM86_SCREEN_BITMAP      0x0001
 119
 120 struct vm86plus_info_struct {
 121         unsigned long force_return_for_pic:1;
 122         unsigned long vm86dbg_active:1;       /* for debugger */
 123         unsigned long vm86dbg_TFpendig:1;     /* for debugger */
 124         unsigned long unused:28;
 125         unsigned long is_vm86pus:1;           /* for vm86 internal use */
 126         unsigned char vm86dbg_intxxtab[32];   /* for debugger */
 127 };
 128
 129 struct vm86plus_struct {
 130         struct vm86_regs regs;
 131         unsigned long flags;
 132         unsigned long screen_bitmap;
 133         unsigned long cpu_type;
 134         struct revectored_struct int_revectored;
 135         struct revectored_struct int21_revectored;
 136         struct vm86plus_info_struct vm86plus;
 137 };
 138
 139 #ifdef __KERNEL__
 140 /*
 141  * This is the (kernel) stack-layout when we have done a "SAVE_ALL" from vm86
 142  * mode - the main change is that the old segment descriptors aren't
 143  * useful any more and are forced to be zero by the kernel (and the
 144  * hardware when a trap occurs), and the real segment descriptors are
 145  * at the end of the structure. Look at ptrace.h to see the "normal"
 146  * setup. For user space layout see 'struct vm86_regs' above.
 147  */
 148
 149 struct kernel_vm86_regs {
 150 /*
 151  * normal regs, with special meaning for the segment descriptors..
 152  */
 153         long ebx;
 154         long ecx;
 155         long edx;
 156         long esi;
 157         long edi;
 158         long ebp;
 159         long eax;
 160         long __null_ds;
 161         long __null_es;
 162         long orig_eax;
 163         long eip;
 164         unsigned short cs, __csh;
 165         long eflags;
 166         long esp;
 167         unsigned short ss, __ssh;
 168 /*
 169  * these are specific to v86 mode:
 170  */
 171         unsigned short es, __esh;
 172         unsigned short ds, __dsh;
 173         unsigned short fs, __fsh;
 174         unsigned short gs, __gsh;
 175 };
 176
 177 struct kernel_vm86_struct {
 178         struct kernel_vm86_regs regs;
 179 /*
 180  * the below part remains on the kernel stack while we are in VM86 mode.
 181  * 'tss.esp0' then contains the address of VM86_TSS_ESP0 below, and when we
 182  * get forced back from VM86, the CPU and "SAVE_ALL" will restore the above
 183  * 'struct kernel_vm86_regs' with the then actual values.
 184  * Therefore, pt_regs in fact points to a complete 'kernel_vm86_struct'
 185  * in kernelspace, hence we need not reget the data from userspace.
 186  */
 187 #define VM86_TSS_ESP0 flags
 188         unsigned long flags;
 189         unsigned long screen_bitmap;
 190         unsigned long cpu_type;
 191         struct revectored_struct int_revectored;
 192         struct revectored_struct int21_revectored;
 193         struct vm86plus_info_struct vm86plus;
 194         struct pt_regs *regs32;   /* here we save the pointer to the old regs */
 195 /*
 196  * The below is not part of the structure, but the stack layout continues
 197  * this way. In front of 'return-eip' may be some data, depending on
 198  * compilation, so we don't rely on this and save the pointer to 'oldregs'
 199  * in 'regs32' above.
 200  * However, with GCC-2.7.2 and the current CFLAGS you see exactly this:
 201
 202         long return-eip;        from call to vm86()
 203         struct pt_regs oldregs;  user space registers as saved by syscall
 204  */
 205 };
 206
 207 #ifdef CONFIG_VM86
 208
 209 void handle_vm86_fault(struct kernel_vm86_regs *, long);
 210 int handle_vm86_trap(struct kernel_vm86_regs *, long, int);
 211
 212 struct task_struct;
 213 void release_vm86_irqs(struct task_struct *);
 214
 215 #else
 216
 217 #define handle_vm86_fault(a, b)
 218 #define release_vm86_irqs(a)
 219
 220 static inline int handle_vm86_trap(struct kernel_vm86_regs *a, long b, int c) {
 221         return 0;
 222 }
 223
 224 #endif /* CONFIG_VM86 */
 225
 226 #endif /* __KERNEL__ */
 227
 228 #endif