1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*---------------------------------------------------------------------------+
3  |  fpu_system.h                                                             |
4  |                                                                           |
5  | Copyright (C) 1992,1994,1997                                              |
6  |                       W. Metzenthen, 22 Parker St, Ormond, Vic 3163,      |
7  |                       Australia.  E-mail   billm@suburbia.net             |
8  |                                                                           |
9  +---------------------------------------------------------------------------*/
10 
11 #ifndef _FPU_SYSTEM_H
12 #define _FPU_SYSTEM_H
13 
14 /* system dependent definitions */
15 
16 #include <linux/sched.h>
17 #include <linux/kernel.h>
18 #include <linux/mm.h>
19 
20 #include <asm/desc.h>
21 #include <asm/mmu_context.h>
22 
FPU_get_ldt_descriptor(unsigned seg)23 static inline struct desc_struct FPU_get_ldt_descriptor(unsigned seg)
24 {
25 	static struct desc_struct zero_desc;
26 	struct desc_struct ret = zero_desc;
27 
28 #ifdef CONFIG_MODIFY_LDT_SYSCALL
29 	seg >>= 3;
30 	mutex_lock(&current->mm->context.lock);
31 	if (current->mm->context.ldt && seg < current->mm->context.ldt->nr_entries)
32 		ret = current->mm->context.ldt->entries[seg];
33 	mutex_unlock(&current->mm->context.lock);
34 #endif
35 	return ret;
36 }
37 
38 #define SEG_TYPE_WRITABLE	(1U << 1)
39 #define SEG_TYPE_EXPANDS_DOWN	(1U << 2)
40 #define SEG_TYPE_EXECUTE	(1U << 3)
41 #define SEG_TYPE_EXPAND_MASK	(SEG_TYPE_EXPANDS_DOWN | SEG_TYPE_EXECUTE)
42 #define SEG_TYPE_EXECUTE_MASK	(SEG_TYPE_WRITABLE | SEG_TYPE_EXECUTE)
43 
seg_get_base(struct desc_struct * d)44 static inline unsigned long seg_get_base(struct desc_struct *d)
45 {
46 	unsigned long base = (unsigned long)d->base2 << 24;
47 
48 	return base | ((unsigned long)d->base1 << 16) | d->base0;
49 }
50 
seg_get_limit(struct desc_struct * d)51 static inline unsigned long seg_get_limit(struct desc_struct *d)
52 {
53 	return ((unsigned long)d->limit1 << 16) | d->limit0;
54 }
55 
seg_get_granularity(struct desc_struct * d)56 static inline unsigned long seg_get_granularity(struct desc_struct *d)
57 {
58 	return d->g ? 4096 : 1;
59 }
60 
seg_expands_down(struct desc_struct * d)61 static inline bool seg_expands_down(struct desc_struct *d)
62 {
63 	return (d->type & SEG_TYPE_EXPAND_MASK) == SEG_TYPE_EXPANDS_DOWN;
64 }
65 
seg_execute_only(struct desc_struct * d)66 static inline bool seg_execute_only(struct desc_struct *d)
67 {
68 	return (d->type & SEG_TYPE_EXECUTE_MASK) == SEG_TYPE_EXECUTE;
69 }
70 
seg_writable(struct desc_struct * d)71 static inline bool seg_writable(struct desc_struct *d)
72 {
73 	return (d->type & SEG_TYPE_EXECUTE_MASK) == SEG_TYPE_WRITABLE;
74 }
75 
76 #define I387			(&current->thread.fpu.fpstate->regs)
77 #define FPU_info		(I387->soft.info)
78 
79 #define FPU_CS			(*(unsigned short *) &(FPU_info->regs->cs))
80 #define FPU_SS			(*(unsigned short *) &(FPU_info->regs->ss))
81 #define FPU_DS			(*(unsigned short *) &(FPU_info->regs->ds))
82 #define FPU_EAX			(FPU_info->regs->ax)
83 #define FPU_EFLAGS		(FPU_info->regs->flags)
84 #define FPU_EIP			(FPU_info->regs->ip)
85 #define FPU_ORIG_EIP		(FPU_info->___orig_eip)
86 
87 #define FPU_lookahead           (I387->soft.lookahead)
88 
89 /* nz if ip_offset and cs_selector are not to be set for the current
90    instruction. */
91 #define no_ip_update		(*(u_char *)&(I387->soft.no_update))
92 #define FPU_rm			(*(u_char *)&(I387->soft.rm))
93 
94 /* Number of bytes of data which can be legally accessed by the current
95    instruction. This only needs to hold a number <= 108, so a byte will do. */
96 #define access_limit		(*(u_char *)&(I387->soft.alimit))
97 
98 #define partial_status		(I387->soft.swd)
99 #define control_word		(I387->soft.cwd)
100 #define fpu_tag_word		(I387->soft.twd)
101 #define registers		(I387->soft.st_space)
102 #define top			(I387->soft.ftop)
103 
104 #define instruction_address	(*(struct address *)&I387->soft.fip)
105 #define operand_address		(*(struct address *)&I387->soft.foo)
106 
107 #define FPU_access_ok(y,z)	if ( !access_ok(y,z) ) \
108 				math_abort(FPU_info,SIGSEGV)
109 #define FPU_abort		math_abort(FPU_info, SIGSEGV)
110 #define FPU_copy_from_user(to, from, n)	\
111 		do { if (copy_from_user(to, from, n)) FPU_abort; } while (0)
112 
113 #undef FPU_IGNORE_CODE_SEGV
114 #ifdef FPU_IGNORE_CODE_SEGV
115 /* access_ok() is very expensive, and causes the emulator to run
116    about 20% slower if applied to the code. Anyway, errors due to bad
117    code addresses should be much rarer than errors due to bad data
118    addresses. */
119 #define	FPU_code_access_ok(z)
120 #else
121 /* A simpler test than access_ok() can probably be done for
122    FPU_code_access_ok() because the only possible error is to step
123    past the upper boundary of a legal code area. */
124 #define	FPU_code_access_ok(z) FPU_access_ok((void __user *)FPU_EIP,z)
125 #endif
126 
127 #define FPU_get_user(x,y) do { if (get_user((x),(y))) FPU_abort; } while (0)
128 #define FPU_put_user(x,y) do { if (put_user((x),(y))) FPU_abort; } while (0)
129 
130 #endif
131