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1da177e4 LT |
1 | /* |
2 | * Copyright 2002 Andi Kleen, SuSE Labs. | |
3 | * FXSAVE<->i387 conversion support. Based on code by Gareth Hughes. | |
4 | * This is used for ptrace, signals and coredumps in 32bit emulation. | |
1da177e4 LT |
5 | */ |
6 | ||
7 | #include <linux/sched.h> | |
8 | #include <asm/sigcontext32.h> | |
9 | #include <asm/processor.h> | |
10 | #include <asm/uaccess.h> | |
11 | #include <asm/i387.h> | |
12 | ||
13 | static inline unsigned short twd_i387_to_fxsr(unsigned short twd) | |
14 | { | |
15 | unsigned int tmp; /* to avoid 16 bit prefixes in the code */ | |
16 | ||
17 | /* Transform each pair of bits into 01 (valid) or 00 (empty) */ | |
18 | tmp = ~twd; | |
19 | tmp = (tmp | (tmp>>1)) & 0x5555; /* 0V0V0V0V0V0V0V0V */ | |
20 | /* and move the valid bits to the lower byte. */ | |
21 | tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */ | |
22 | tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */ | |
23 | tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */ | |
24 | return tmp; | |
25 | } | |
26 | ||
27 | static inline unsigned long twd_fxsr_to_i387(struct i387_fxsave_struct *fxsave) | |
28 | { | |
29 | struct _fpxreg *st = NULL; | |
30 | unsigned long tos = (fxsave->swd >> 11) & 7; | |
31 | unsigned long twd = (unsigned long) fxsave->twd; | |
32 | unsigned long tag; | |
33 | unsigned long ret = 0xffff0000; | |
34 | int i; | |
35 | ||
36 | #define FPREG_ADDR(f, n) ((void *)&(f)->st_space + (n) * 16); | |
37 | ||
38 | for (i = 0 ; i < 8 ; i++) { | |
39 | if (twd & 0x1) { | |
40 | st = FPREG_ADDR( fxsave, (i - tos) & 7 ); | |
41 | ||
42 | switch (st->exponent & 0x7fff) { | |
43 | case 0x7fff: | |
44 | tag = 2; /* Special */ | |
45 | break; | |
46 | case 0x0000: | |
47 | if ( !st->significand[0] && | |
48 | !st->significand[1] && | |
49 | !st->significand[2] && | |
50 | !st->significand[3] ) { | |
51 | tag = 1; /* Zero */ | |
52 | } else { | |
53 | tag = 2; /* Special */ | |
54 | } | |
55 | break; | |
56 | default: | |
57 | if (st->significand[3] & 0x8000) { | |
58 | tag = 0; /* Valid */ | |
59 | } else { | |
60 | tag = 2; /* Special */ | |
61 | } | |
62 | break; | |
63 | } | |
64 | } else { | |
65 | tag = 3; /* Empty */ | |
66 | } | |
67 | ret |= (tag << (2 * i)); | |
68 | twd = twd >> 1; | |
69 | } | |
70 | return ret; | |
71 | } | |
72 | ||
73 | ||
74 | static inline int convert_fxsr_from_user(struct i387_fxsave_struct *fxsave, | |
75 | struct _fpstate_ia32 __user *buf) | |
76 | { | |
77 | struct _fpxreg *to; | |
78 | struct _fpreg __user *from; | |
79 | int i; | |
80 | u32 v; | |
81 | int err = 0; | |
82 | ||
83 | #define G(num,val) err |= __get_user(val, num + (u32 __user *)buf) | |
84 | G(0, fxsave->cwd); | |
85 | G(1, fxsave->swd); | |
86 | G(2, fxsave->twd); | |
87 | fxsave->twd = twd_i387_to_fxsr(fxsave->twd); | |
88 | G(3, fxsave->rip); | |
89 | G(4, v); | |
90 | fxsave->fop = v>>16; /* cs ignored */ | |
91 | G(5, fxsave->rdp); | |
92 | /* 6: ds ignored */ | |
93 | #undef G | |
94 | if (err) | |
95 | return -1; | |
96 | ||
97 | to = (struct _fpxreg *)&fxsave->st_space[0]; | |
98 | from = &buf->_st[0]; | |
99 | for (i = 0 ; i < 8 ; i++, to++, from++) { | |
100 | if (__copy_from_user(to, from, sizeof(*from))) | |
101 | return -1; | |
102 | } | |
103 | return 0; | |
104 | } | |
105 | ||
106 | ||
107 | static inline int convert_fxsr_to_user(struct _fpstate_ia32 __user *buf, | |
108 | struct i387_fxsave_struct *fxsave, | |
109 | struct pt_regs *regs, | |
110 | struct task_struct *tsk) | |
111 | { | |
112 | struct _fpreg __user *to; | |
113 | struct _fpxreg *from; | |
114 | int i; | |
115 | u16 cs,ds; | |
116 | int err = 0; | |
117 | ||
118 | if (tsk == current) { | |
119 | /* should be actually ds/cs at fpu exception time, | |
120 | but that information is not available in 64bit mode. */ | |
121 | asm("movw %%ds,%0 " : "=r" (ds)); | |
122 | asm("movw %%cs,%0 " : "=r" (cs)); | |
123 | } else { /* ptrace. task has stopped. */ | |
124 | ds = tsk->thread.ds; | |
125 | cs = regs->cs; | |
126 | } | |
127 | ||
128 | #define P(num,val) err |= __put_user(val, num + (u32 __user *)buf) | |
129 | P(0, (u32)fxsave->cwd | 0xffff0000); | |
130 | P(1, (u32)fxsave->swd | 0xffff0000); | |
131 | P(2, twd_fxsr_to_i387(fxsave)); | |
132 | P(3, (u32)fxsave->rip); | |
133 | P(4, cs | ((u32)fxsave->fop) << 16); | |
134 | P(5, fxsave->rdp); | |
135 | P(6, 0xffff0000 | ds); | |
136 | #undef P | |
137 | ||
138 | if (err) | |
139 | return -1; | |
140 | ||
141 | to = &buf->_st[0]; | |
142 | from = (struct _fpxreg *) &fxsave->st_space[0]; | |
143 | for ( i = 0 ; i < 8 ; i++, to++, from++ ) { | |
144 | if (__copy_to_user(to, from, sizeof(*to))) | |
145 | return -1; | |
146 | } | |
147 | return 0; | |
148 | } | |
149 | ||
150 | int restore_i387_ia32(struct task_struct *tsk, struct _fpstate_ia32 __user *buf, int fsave) | |
151 | { | |
152 | clear_fpu(tsk); | |
153 | if (!fsave) { | |
154 | if (__copy_from_user(&tsk->thread.i387.fxsave, | |
155 | &buf->_fxsr_env[0], | |
156 | sizeof(struct i387_fxsave_struct))) | |
157 | return -1; | |
158 | tsk->thread.i387.fxsave.mxcsr &= mxcsr_feature_mask; | |
159 | set_stopped_child_used_math(tsk); | |
160 | } | |
161 | return convert_fxsr_from_user(&tsk->thread.i387.fxsave, buf); | |
162 | } | |
163 | ||
164 | int save_i387_ia32(struct task_struct *tsk, | |
165 | struct _fpstate_ia32 __user *buf, | |
166 | struct pt_regs *regs, | |
167 | int fsave) | |
168 | { | |
169 | int err = 0; | |
170 | ||
171 | init_fpu(tsk); | |
172 | if (convert_fxsr_to_user(buf, &tsk->thread.i387.fxsave, regs, tsk)) | |
173 | return -1; | |
174 | if (fsave) | |
175 | return 0; | |
176 | err |= __put_user(tsk->thread.i387.fxsave.swd, &buf->status); | |
177 | if (fsave) | |
178 | return err ? -1 : 1; | |
179 | err |= __put_user(X86_FXSR_MAGIC, &buf->magic); | |
180 | err |= __copy_to_user(&buf->_fxsr_env[0], &tsk->thread.i387.fxsave, | |
181 | sizeof(struct i387_fxsave_struct)); | |
182 | return err ? -1 : 1; | |
183 | } |