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
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(¤t->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(¤t->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
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
51 static inline unsigned long seg_get_limit(struct desc_struct *d)
52 {
53 return ((unsigned long)d->limit1 << 16) | d->limit0;
54 }
55
56 static inline unsigned long seg_get_granularity(struct desc_struct *d)
57 {
58 return d->g ? 4096 : 1;
59 }
60
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
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
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 (¤t->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
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