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/* This sets the pointer FPU_info to point to the argument part
20   of the stack frame of math_emulate() */
21#define SETUP_DATA_AREA(arg)	FPU_info = (struct info *) &arg
22
23/* s is always from a cpu register, and the cpu does bounds checking
24 * during register load --> no further bounds checks needed */
25#define LDT_DESCRIPTOR(s)	(((struct desc_struct *)current->mm->context.ldt)[(s) >> 3])
26#define SEG_D_SIZE(x)		((x).b & (3 << 21))
27#define SEG_G_BIT(x)		((x).b & (1 << 23))
28#define SEG_GRANULARITY(x)	(((x).b & (1 << 23)) ? 4096 : 1)
29#define SEG_286_MODE(x)		((x).b & ( 0xff000000 | 0xf0000 | (1 << 23)))
30#define SEG_BASE_ADDR(s)	(((s).b & 0xff000000) \
31				 | (((s).b & 0xff) << 16) | ((s).a >> 16))
32#define SEG_LIMIT(s)		(((s).b & 0xff0000) | ((s).a & 0xffff))
33#define SEG_EXECUTE_ONLY(s)	(((s).b & ((1 << 11) | (1 << 9))) == (1 << 11))
34#define SEG_WRITE_PERM(s)	(((s).b & ((1 << 11) | (1 << 9))) == (1 << 9))
35#define SEG_EXPAND_DOWN(s)	(((s).b & ((1 << 11) | (1 << 10))) \
36				 == (1 << 10))
37
38#define I387			(current->thread.i387)
39#define FPU_info		(I387.soft.info)
40
41#define FPU_CS			(*(unsigned short *) &(FPU_info->___cs))
42#define FPU_SS			(*(unsigned short *) &(FPU_info->___ss))
43#define FPU_DS			(*(unsigned short *) &(FPU_info->___ds))
44#define FPU_EAX			(FPU_info->___eax)
45#define FPU_EFLAGS		(FPU_info->___eflags)
46#define FPU_EIP			(FPU_info->___eip)
47#define FPU_ORIG_EIP		(FPU_info->___orig_eip)
48
49#define FPU_lookahead           (I387.soft.lookahead)
50
51/* nz if ip_offset and cs_selector are not to be set for the current
52   instruction. */
53#define no_ip_update		(*(u_char *)&(I387.soft.no_update))
54#define FPU_rm			(*(u_char *)&(I387.soft.rm))
55
56/* Number of bytes of data which can be legally accessed by the current
57   instruction. This only needs to hold a number <= 108, so a byte will do. */
58#define access_limit		(*(u_char *)&(I387.soft.alimit))
59
60#define partial_status		(I387.soft.swd)
61#define control_word		(I387.soft.cwd)
62#define fpu_tag_word		(I387.soft.twd)
63#define registers		(I387.soft.st_space)
64#define top			(I387.soft.ftop)
65
66#define instruction_address	(*(struct address *)&I387.soft.fip)
67#define operand_address		(*(struct address *)&I387.soft.foo)
68
69#define FPU_access_ok(x,y,z)	if ( !access_ok(x,y,z) ) \
70				math_abort(FPU_info,SIGSEGV)
71#define FPU_abort		math_abort(FPU_info, SIGSEGV)
72
73#undef FPU_IGNORE_CODE_SEGV
74#ifdef FPU_IGNORE_CODE_SEGV
75/* access_ok() is very expensive, and causes the emulator to run
76   about 20% slower if applied to the code. Anyway, errors due to bad
77   code addresses should be much rarer than errors due to bad data
78   addresses. */
79#define	FPU_code_access_ok(z)
80#else
81/* A simpler test than access_ok() can probably be done for
82   FPU_code_access_ok() because the only possible error is to step
83   past the upper boundary of a legal code area. */
84#define	FPU_code_access_ok(z) FPU_access_ok(VERIFY_READ,(void __user *)FPU_EIP,z)
85#endif
86
87#define FPU_get_user(x,y)       get_user((x),(y))
88#define FPU_put_user(x,y)       put_user((x),(y))
89
90#endif
91