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
72struct 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
102struct revectored_struct {
103	unsigned long __map[8];			/* 256 bits */
104};
105
106struct 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
120struct 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
129struct 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#include <asm/ptrace.h>
149
150struct kernel_vm86_regs {
151/*
152 * normal regs, with special meaning for the segment descriptors..
153 */
154	struct pt_regs pt;
155/*
156 * these are specific to v86 mode:
157 */
158	unsigned short es, __esh;
159	unsigned short ds, __dsh;
160	unsigned short fs, __fsh;
161	unsigned short gs, __gsh;
162};
163
164struct kernel_vm86_struct {
165	struct kernel_vm86_regs regs;
166/*
167 * the below part remains on the kernel stack while we are in VM86 mode.
168 * 'tss.esp0' then contains the address of VM86_TSS_ESP0 below, and when we
169 * get forced back from VM86, the CPU and "SAVE_ALL" will restore the above
170 * 'struct kernel_vm86_regs' with the then actual values.
171 * Therefore, pt_regs in fact points to a complete 'kernel_vm86_struct'
172 * in kernelspace, hence we need not reget the data from userspace.
173 */
174#define VM86_TSS_ESP0 flags
175	unsigned long flags;
176	unsigned long screen_bitmap;
177	unsigned long cpu_type;
178	struct revectored_struct int_revectored;
179	struct revectored_struct int21_revectored;
180	struct vm86plus_info_struct vm86plus;
181	struct pt_regs *regs32;   /* here we save the pointer to the old regs */
182/*
183 * The below is not part of the structure, but the stack layout continues
184 * this way. In front of 'return-eip' may be some data, depending on
185 * compilation, so we don't rely on this and save the pointer to 'oldregs'
186 * in 'regs32' above.
187 * However, with GCC-2.7.2 and the current CFLAGS you see exactly this:
188
189	long return-eip;        from call to vm86()
190	struct pt_regs oldregs;  user space registers as saved by syscall
191 */
192};
193
194#ifdef CONFIG_VM86
195
196void handle_vm86_fault(struct kernel_vm86_regs *, long);
197int handle_vm86_trap(struct kernel_vm86_regs *, long, int);
198
199struct task_struct;
200void release_vm86_irqs(struct task_struct *);
201
202#else
203
204#define handle_vm86_fault(a, b)
205#define release_vm86_irqs(a)
206
207static inline int handle_vm86_trap(struct kernel_vm86_regs *a, long b, int c) {
208	return 0;
209}
210
211#endif /* CONFIG_VM86 */
212
213#endif /* __KERNEL__ */
214
215#endif
216