Linux Kernel  3.7.1
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vm86.h
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1 #ifndef _ASM_X86_VM86_H
2 #define _ASM_X86_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;
103 };
104 
105 /*
106  * flags masks
107  */
108 #define VM86_SCREEN_BITMAP 0x0001
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 };
119  struct vm86_regs regs;
120  unsigned long flags;
121  unsigned long screen_bitmap;
122  unsigned long cpu_type;
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 /* _ASM_X86_VM86_H */