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 #ifdef CONFIG_VM86
  18 #define X86_VM_MASK     X86_EFLAGS_VM
  19 #else
  20 #define X86_VM_MASK     0 /* No VM86 support */
  21 #endif
  22
  23 #define BIOSSEG         0x0f000
  24
  25 #define CPU_086         0
  26 #define CPU_186         1
  27 #define CPU_286         2
  28 #define CPU_386         3
  29 #define CPU_486         4
  30 #define CPU_586         5
  31
  32 /*
  33  * Return values for the 'vm86()' system call
  34  */
  35 #define VM86_TYPE(retval)       ((retval) & 0xff)
  36 #define VM86_ARG(retval)        ((retval) >> 8)
  37
  38 #define VM86_SIGNAL     0       /* return due to signal */
  39 #define VM86_UNKNOWN    1       /* unhandled GP fault
  40                                    - IO-instruction or similar */
  41 #define VM86_INTx       2       /* int3/int x instruction (ARG = x) */
  42 #define VM86_STI        3       /* sti/popf/iret instruction enabled
  43                                    virtual interrupts */
  44
  45 /*
  46  * Additional return values when invoking new vm86()
  47  */
  48 #define VM86_PICRETURN  4       /* return due to pending PIC request */
  49 #define VM86_TRAP       6       /* return due to DOS-debugger request */
  50
  51 /*
  52  * function codes when invoking new vm86()
  53  */
  54 #define VM86_PLUS_INSTALL_CHECK 0
  55 #define VM86_ENTER              1
  56 #define VM86_ENTER_NO_BYPASS    2
  57 #define VM86_REQUEST_IRQ        3
  58 #define VM86_FREE_IRQ           4
  59 #define VM86_GET_IRQ_BITS       5
  60 #define VM86_GET_AND_RESET_IRQ  6
  61
  62 /*
  63  * This is the stack-layout seen by the user space program when we have
  64  * done a translation of "SAVE_ALL" from vm86 mode. The real kernel layout
  65  * is 'kernel_vm86_regs' (see below).
  66  */
  67
  68 struct vm86_regs {
  69 /*
  70  * normal regs, with special meaning for the segment descriptors..
  71  */
  72         long ebx;
  73         long ecx;
  74         long edx;
  75         long esi;
  76         long edi;
  77         long ebp;
  78         long eax;
  79         long __null_ds;
  80         long __null_es;
  81         long __null_fs;
  82         long __null_gs;
  83         long orig_eax;
  84         long eip;
  85         unsigned short cs, __csh;
  86         long eflags;
  87         long esp;
  88         unsigned short ss, __ssh;
  89 /*
  90  * these are specific to v86 mode:
  91  */
  92         unsigned short es, __esh;
  93         unsigned short ds, __dsh;
  94         unsigned short fs, __fsh;
  95         unsigned short gs, __gsh;
  96 };
  97
  98 struct revectored_struct {
  99         unsigned long __map[8];                 /* 256 bits */
 100 };
 101
 102 struct vm86_struct {
 103         struct vm86_regs regs;
 104         unsigned long flags;
 105         unsigned long screen_bitmap;
 106         unsigned long cpu_type;
 107         struct revectored_struct int_revectored;
 108         struct revectored_struct int21_revectored;
 109 };
 110
 111 /*
 112  * flags masks
 113  */
 114 #define VM86_SCREEN_BITMAP      0x0001
 115
 116 struct vm86plus_info_struct {
 117         unsigned long force_return_for_pic:1;
 118         unsigned long vm86dbg_active:1;       /* for debugger */
 119         unsigned long vm86dbg_TFpendig:1;     /* for debugger */
 120         unsigned long unused:28;
 121         unsigned long is_vm86pus:1;           /* for vm86 internal use */
 122         unsigned char vm86dbg_intxxtab[32];   /* for debugger */
 123 };
 124
 125 struct vm86plus_struct {
 126         struct vm86_regs regs;
 127         unsigned long flags;
 128         unsigned long screen_bitmap;
 129         unsigned long cpu_type;
 130         struct revectored_struct int_revectored;
 131         struct revectored_struct int21_revectored;
 132         struct vm86plus_info_struct vm86plus;
 133 };
 134
 135 #ifdef __KERNEL__
 136 /*
 137  * This is the (kernel) stack-layout when we have done a "SAVE_ALL" from vm86
 138  * mode - the main change is that the old segment descriptors aren't
 139  * useful any more and are forced to be zero by the kernel (and the
 140  * hardware when a trap occurs), and the real segment descriptors are
 141  * at the end of the structure. Look at ptrace.h to see the "normal"
 142  * setup. For user space layout see 'struct vm86_regs' above.
 143  */
 144 #include <asm/ptrace.h>
 145
 146 struct kernel_vm86_regs {
 147 /*
 148  * normal regs, with special meaning for the segment descriptors..
 149  */
 150         struct pt_regs pt;
 151 /*
 152  * these are specific to v86 mode:
 153  */
 154         unsigned short es, __esh;
 155         unsigned short ds, __dsh;
 156         unsigned short fs, __fsh;
 157         unsigned short gs, __gsh;
 158 };
 159
 160 struct kernel_vm86_struct {
 161         struct kernel_vm86_regs regs;
 162 /*
 163  * the below part remains on the kernel stack while we are in VM86 mode.
 164  * 'tss.esp0' then contains the address of VM86_TSS_ESP0 below, and when we
 165  * get forced back from VM86, the CPU and "SAVE_ALL" will restore the above
 166  * 'struct kernel_vm86_regs' with the then actual values.
 167  * Therefore, pt_regs in fact points to a complete 'kernel_vm86_struct'
 168  * in kernelspace, hence we need not reget the data from userspace.
 169  */
 170 #define VM86_TSS_ESP0 flags
 171         unsigned long flags;
 172         unsigned long screen_bitmap;
 173         unsigned long cpu_type;
 174         struct revectored_struct int_revectored;
 175         struct revectored_struct int21_revectored;
 176         struct vm86plus_info_struct vm86plus;
 177         struct pt_regs *regs32;   /* here we save the pointer to the old regs */
 178 /*
 179  * The below is not part of the structure, but the stack layout continues
 180  * this way. In front of 'return-eip' may be some data, depending on
 181  * compilation, so we don't rely on this and save the pointer to 'oldregs'
 182  * in 'regs32' above.
 183  * However, with GCC-2.7.2 and the current CFLAGS you see exactly this:
 184
 185         long return-eip;        from call to vm86()
 186         struct pt_regs oldregs;  user space registers as saved by syscall
 187  */
 188 };
 189
 190 #ifdef CONFIG_VM86
 191
 192 void handle_vm86_fault(struct kernel_vm86_regs *, long);
 193 int handle_vm86_trap(struct kernel_vm86_regs *, long, int);
 194 struct pt_regs *save_v86_state(struct kernel_vm86_regs *);
 195
 196 struct task_struct;
 197 void release_vm86_irqs(struct task_struct *);
 198
 199 #else
 200
 201 #define handle_vm86_fault(a, b)
 202 #define release_vm86_irqs(a)
 203
 204 static inline int handle_vm86_trap(struct kernel_vm86_regs *a, long b, int c)
 205 {
 206         return 0;
 207 }
 208
 209 #endif /* CONFIG_VM86 */
 210
 211 #endif /* __KERNEL__ */
 212
 213 #endif