include/asm-x86/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 #include <asm/processor-flags.h>
  16
  17 #define BIOSSEG         0x0f000
  18
  19 #define CPU_086         0
  20 #define CPU_186         1
  21 #define CPU_286         2
  22 #define CPU_386         3
  23 #define CPU_486         4
  24 #define CPU_586         5
  25
  26 /*
  27  * Return values for the 'vm86()' system call
  28  */
  29 #define VM86_TYPE(retval)       ((retval) & 0xff)
  30 #define VM86_ARG(retval)        ((retval) >> 8)
  31
  32 #define VM86_SIGNAL     0       /* return due to signal */
  33 #define VM86_UNKNOWN    1       /* unhandled GP fault
  34                                    - IO-instruction or similar */
  35 #define VM86_INTx       2       /* int3/int x instruction (ARG = x) */
  36 #define VM86_STI        3       /* sti/popf/iret instruction enabled
  37                                    virtual interrupts */
  38
  39 /*
  40  * Additional return values when invoking new vm86()
  41  */
  42 #define VM86_PICRETURN  4       /* return due to pending PIC request */
  43 #define VM86_TRAP       6       /* return due to DOS-debugger request */
  44
  45 /*
  46  * function codes when invoking new vm86()
  47  */
  48 #define VM86_PLUS_INSTALL_CHECK 0
  49 #define VM86_ENTER              1
  50 #define VM86_ENTER_NO_BYPASS    2
  51 #define VM86_REQUEST_IRQ        3
  52 #define VM86_FREE_IRQ           4
  53 #define VM86_GET_IRQ_BITS       5
  54 #define VM86_GET_AND_RESET_IRQ  6
  55
  56 /*
  57  * This is the stack-layout seen by the user space program when we have
  58  * done a translation of "SAVE_ALL" from vm86 mode. The real kernel layout
  59  * is 'kernel_vm86_regs' (see below).
  60  */
  61
  62 struct vm86_regs {
  63 /*
  64  * normal regs, with special meaning for the segment descriptors..
  65  */
  66         long ebx;
  67         long ecx;
  68         long edx;
  69         long esi;
  70         long edi;
  71         long ebp;
  72         long eax;
  73         long __null_ds;
  74         long __null_es;
  75         long __null_fs;
  76         long __null_gs;
  77         long orig_eax;
  78         long eip;
  79         unsigned short cs, __csh;
  80         long eflags;
  81         long esp;
  82         unsigned short ss, __ssh;
  83 /*
  84  * these are specific to v86 mode:
  85  */
  86         unsigned short es, __esh;
  87         unsigned short ds, __dsh;
  88         unsigned short fs, __fsh;
  89         unsigned short gs, __gsh;
  90 };
  91
  92 struct revectored_struct {
  93         unsigned long __map[8];                 /* 256 bits */
  94 };
  95
  96 struct vm86_struct {
  97         struct vm86_regs regs;
  98         unsigned long flags;
  99         unsigned long screen_bitmap;
 100         unsigned long cpu_type;
 101         struct revectored_struct int_revectored;
 102         struct revectored_struct int21_revectored;
 103 };
 104
 105 /*
 106  * flags masks
 107  */
 108 #define VM86_SCREEN_BITMAP      0x0001
 109
 110 struct vm86plus_info_struct {
 111         unsigned long force_return_for_pic:1;
 112         unsigned long vm86dbg_active:1;       /* for debugger */
 113         unsigned long vm86dbg_TFpendig:1;     /* for debugger */
 114         unsigned long unused:28;
 115         unsigned long is_vm86pus:1;           /* for vm86 internal use */
 116         unsigned char vm86dbg_intxxtab[32];   /* for debugger */
 117 };
 118 struct vm86plus_struct {
 119         struct vm86_regs regs;
 120         unsigned long flags;
 121         unsigned long screen_bitmap;
 122         unsigned long cpu_type;
 123         struct revectored_struct int_revectored;
 124         struct revectored_struct int21_revectored;
 125         struct vm86plus_info_struct vm86plus;
 126 };
 127
 128 #ifdef __KERNEL__
 129
 130 #include <asm/ptrace.h>
 131
 132 /*
 133  * This is the (kernel) stack-layout when we have done a "SAVE_ALL" from vm86
 134  * mode - the main change is that the old segment descriptors aren't
 135  * useful any more and are forced to be zero by the kernel (and the
 136  * hardware when a trap occurs), and the real segment descriptors are
 137  * at the end of the structure. Look at ptrace.h to see the "normal"
 138  * setup. For user space layout see 'struct vm86_regs' above.
 139  */
 140
 141 struct kernel_vm86_regs {
 142 /*
 143  * normal regs, with special meaning for the segment descriptors..
 144  */
 145         struct pt_regs pt;
 146 /*
 147  * these are specific to v86 mode:
 148  */
 149         unsigned short es, __esh;
 150         unsigned short ds, __dsh;
 151         unsigned short fs, __fsh;
 152         unsigned short gs, __gsh;
 153 };
 154
 155 struct kernel_vm86_struct {
 156         struct kernel_vm86_regs regs;
 157 /*
 158  * the below part remains on the kernel stack while we are in VM86 mode.
 159  * 'tss.esp0' then contains the address of VM86_TSS_ESP0 below, and when we
 160  * get forced back from VM86, the CPU and "SAVE_ALL" will restore the above
 161  * 'struct kernel_vm86_regs' with the then actual values.
 162  * Therefore, pt_regs in fact points to a complete 'kernel_vm86_struct'
 163  * in kernelspace, hence we need not reget the data from userspace.
 164  */
 165 #define VM86_TSS_ESP0 flags
 166         unsigned long flags;
 167         unsigned long screen_bitmap;
 168         unsigned long cpu_type;
 169         struct revectored_struct int_revectored;
 170         struct revectored_struct int21_revectored;
 171         struct vm86plus_info_struct vm86plus;
 172         struct pt_regs *regs32;   /* here we save the pointer to the old regs */
 173 /*
 174  * The below is not part of the structure, but the stack layout continues
 175  * this way. In front of 'return-eip' may be some data, depending on
 176  * compilation, so we don't rely on this and save the pointer to 'oldregs'
 177  * in 'regs32' above.
 178  * However, with GCC-2.7.2 and the current CFLAGS you see exactly this:
 179
 180         long return-eip;        from call to vm86()
 181         struct pt_regs oldregs;  user space registers as saved by syscall
 182  */
 183 };
 184
 185 #ifdef CONFIG_VM86
 186
 187 void handle_vm86_fault(struct kernel_vm86_regs *, long);
 188 int handle_vm86_trap(struct kernel_vm86_regs *, long, int);
 189 struct pt_regs *save_v86_state(struct kernel_vm86_regs *);
 190
 191 struct task_struct;
 192 void release_vm86_irqs(struct task_struct *);
 193
 194 #else
 195
 196 #define handle_vm86_fault(a, b)
 197 #define release_vm86_irqs(a)
 198
 199 static inline int handle_vm86_trap(struct kernel_vm86_regs *a, long b, int c)
 200 {
 201         return 0;
 202 }
 203
 204 #endif /* CONFIG_VM86 */
 205
 206 #endif /* __KERNEL__ */
 207
 208 #endif