1 /*---------------------------------------------------------------------------+
2  |  fpu_system.h                                                             |
3  |                                                                           |
4  | Copyright (C) 1992,1994,1997                                              |
5  |                       W. Metzenthen, 22 Parker St, Ormond, Vic 3163,      |
6  |                       Australia.  E-mail   billm@suburbia.net             |
7  |                                                                           |
8  +---------------------------------------------------------------------------*/
9 
10 #ifndef _FPU_SYSTEM_H
11 #define _FPU_SYSTEM_H
12 
13 /* system dependent definitions */
14 
15 #include <linux/sched.h>
16 #include <linux/kernel.h>
17 #include <linux/mm.h>
18 
19 /* s is always from a cpu register, and the cpu does bounds checking
20  * during register load --> no further bounds checks needed */
21 #define LDT_DESCRIPTOR(s)	(((struct desc_struct *)current->mm->context.ldt)[(s) >> 3])
22 #define SEG_D_SIZE(x)		((x).b & (3 << 21))
23 #define SEG_G_BIT(x)		((x).b & (1 << 23))
24 #define SEG_GRANULARITY(x)	(((x).b & (1 << 23)) ? 4096 : 1)
25 #define SEG_286_MODE(x)		((x).b & ( 0xff000000 | 0xf0000 | (1 << 23)))
26 #define SEG_BASE_ADDR(s)	(((s).b & 0xff000000) \
27 				 | (((s).b & 0xff) << 16) | ((s).a >> 16))
28 #define SEG_LIMIT(s)		(((s).b & 0xff0000) | ((s).a & 0xffff))
29 #define SEG_EXECUTE_ONLY(s)	(((s).b & ((1 << 11) | (1 << 9))) == (1 << 11))
30 #define SEG_WRITE_PERM(s)	(((s).b & ((1 << 11) | (1 << 9))) == (1 << 9))
31 #define SEG_EXPAND_DOWN(s)	(((s).b & ((1 << 11) | (1 << 10))) \
32 				 == (1 << 10))
33 
34 #define I387			(current->thread.fpu.state)
35 #define FPU_info		(I387->soft.info)
36 
37 #define FPU_CS			(*(unsigned short *) &(FPU_info->regs->cs))
38 #define FPU_SS			(*(unsigned short *) &(FPU_info->regs->ss))
39 #define FPU_DS			(*(unsigned short *) &(FPU_info->regs->ds))
40 #define FPU_EAX			(FPU_info->regs->ax)
41 #define FPU_EFLAGS		(FPU_info->regs->flags)
42 #define FPU_EIP			(FPU_info->regs->ip)
43 #define FPU_ORIG_EIP		(FPU_info->___orig_eip)
44 
45 #define FPU_lookahead           (I387->soft.lookahead)
46 
47 /* nz if ip_offset and cs_selector are not to be set for the current
48    instruction. */
49 #define no_ip_update		(*(u_char *)&(I387->soft.no_update))
50 #define FPU_rm			(*(u_char *)&(I387->soft.rm))
51 
52 /* Number of bytes of data which can be legally accessed by the current
53    instruction. This only needs to hold a number <= 108, so a byte will do. */
54 #define access_limit		(*(u_char *)&(I387->soft.alimit))
55 
56 #define partial_status		(I387->soft.swd)
57 #define control_word		(I387->soft.cwd)
58 #define fpu_tag_word		(I387->soft.twd)
59 #define registers		(I387->soft.st_space)
60 #define top			(I387->soft.ftop)
61 
62 #define instruction_address	(*(struct address *)&I387->soft.fip)
63 #define operand_address		(*(struct address *)&I387->soft.foo)
64 
65 #define FPU_access_ok(x,y,z)	if ( !access_ok(x,y,z) ) \
66 				math_abort(FPU_info,SIGSEGV)
67 #define FPU_abort		math_abort(FPU_info, SIGSEGV)
68 
69 #undef FPU_IGNORE_CODE_SEGV
70 #ifdef FPU_IGNORE_CODE_SEGV
71 /* access_ok() is very expensive, and causes the emulator to run
72    about 20% slower if applied to the code. Anyway, errors due to bad
73    code addresses should be much rarer than errors due to bad data
74    addresses. */
75 #define	FPU_code_access_ok(z)
76 #else
77 /* A simpler test than access_ok() can probably be done for
78    FPU_code_access_ok() because the only possible error is to step
79    past the upper boundary of a legal code area. */
80 #define	FPU_code_access_ok(z) FPU_access_ok(VERIFY_READ,(void __user *)FPU_EIP,z)
81 #endif
82 
83 #define FPU_get_user(x,y)       get_user((x),(y))
84 #define FPU_put_user(x,y)       put_user((x),(y))
85 
86 #endif
87