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-rw-r--r--arch/x86_64/ia32/fpu32.c184
1 files changed, 184 insertions, 0 deletions
diff --git a/arch/x86_64/ia32/fpu32.c b/arch/x86_64/ia32/fpu32.c
new file mode 100644
index 000000000000..1c23095f1813
--- /dev/null
+++ b/arch/x86_64/ia32/fpu32.c
@@ -0,0 +1,184 @@
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.
5 * $Id: fpu32.c,v 1.1 2002/03/21 14:16:32 ak Exp $
6 */
7
8#include <linux/sched.h>
9#include <asm/sigcontext32.h>
10#include <asm/processor.h>
11#include <asm/uaccess.h>
12#include <asm/i387.h>
13
14static inline unsigned short twd_i387_to_fxsr(unsigned short twd)
15{
16 unsigned int tmp; /* to avoid 16 bit prefixes in the code */
17
18 /* Transform each pair of bits into 01 (valid) or 00 (empty) */
19 tmp = ~twd;
20 tmp = (tmp | (tmp>>1)) & 0x5555; /* 0V0V0V0V0V0V0V0V */
21 /* and move the valid bits to the lower byte. */
22 tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */
23 tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */
24 tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */
25 return tmp;
26}
27
28static inline unsigned long twd_fxsr_to_i387(struct i387_fxsave_struct *fxsave)
29{
30 struct _fpxreg *st = NULL;
31 unsigned long tos = (fxsave->swd >> 11) & 7;
32 unsigned long twd = (unsigned long) fxsave->twd;
33 unsigned long tag;
34 unsigned long ret = 0xffff0000;
35 int i;
36
37#define FPREG_ADDR(f, n) ((void *)&(f)->st_space + (n) * 16);
38
39 for (i = 0 ; i < 8 ; i++) {
40 if (twd & 0x1) {
41 st = FPREG_ADDR( fxsave, (i - tos) & 7 );
42
43 switch (st->exponent & 0x7fff) {
44 case 0x7fff:
45 tag = 2; /* Special */
46 break;
47 case 0x0000:
48 if ( !st->significand[0] &&
49 !st->significand[1] &&
50 !st->significand[2] &&
51 !st->significand[3] ) {
52 tag = 1; /* Zero */
53 } else {
54 tag = 2; /* Special */
55 }
56 break;
57 default:
58 if (st->significand[3] & 0x8000) {
59 tag = 0; /* Valid */
60 } else {
61 tag = 2; /* Special */
62 }
63 break;
64 }
65 } else {
66 tag = 3; /* Empty */
67 }
68 ret |= (tag << (2 * i));
69 twd = twd >> 1;
70 }
71 return ret;
72}
73
74
75static inline int convert_fxsr_from_user(struct i387_fxsave_struct *fxsave,
76 struct _fpstate_ia32 __user *buf)
77{
78 struct _fpxreg *to;
79 struct _fpreg __user *from;
80 int i;
81 u32 v;
82 int err = 0;
83
84#define G(num,val) err |= __get_user(val, num + (u32 __user *)buf)
85 G(0, fxsave->cwd);
86 G(1, fxsave->swd);
87 G(2, fxsave->twd);
88 fxsave->twd = twd_i387_to_fxsr(fxsave->twd);
89 G(3, fxsave->rip);
90 G(4, v);
91 fxsave->fop = v>>16; /* cs ignored */
92 G(5, fxsave->rdp);
93 /* 6: ds ignored */
94#undef G
95 if (err)
96 return -1;
97
98 to = (struct _fpxreg *)&fxsave->st_space[0];
99 from = &buf->_st[0];
100 for (i = 0 ; i < 8 ; i++, to++, from++) {
101 if (__copy_from_user(to, from, sizeof(*from)))
102 return -1;
103 }
104 return 0;
105}
106
107
108static inline int convert_fxsr_to_user(struct _fpstate_ia32 __user *buf,
109 struct i387_fxsave_struct *fxsave,
110 struct pt_regs *regs,
111 struct task_struct *tsk)
112{
113 struct _fpreg __user *to;
114 struct _fpxreg *from;
115 int i;
116 u16 cs,ds;
117 int err = 0;
118
119 if (tsk == current) {
120 /* should be actually ds/cs at fpu exception time,
121 but that information is not available in 64bit mode. */
122 asm("movw %%ds,%0 " : "=r" (ds));
123 asm("movw %%cs,%0 " : "=r" (cs));
124 } else { /* ptrace. task has stopped. */
125 ds = tsk->thread.ds;
126 cs = regs->cs;
127 }
128
129#define P(num,val) err |= __put_user(val, num + (u32 __user *)buf)
130 P(0, (u32)fxsave->cwd | 0xffff0000);
131 P(1, (u32)fxsave->swd | 0xffff0000);
132 P(2, twd_fxsr_to_i387(fxsave));
133 P(3, (u32)fxsave->rip);
134 P(4, cs | ((u32)fxsave->fop) << 16);
135 P(5, fxsave->rdp);
136 P(6, 0xffff0000 | ds);
137#undef P
138
139 if (err)
140 return -1;
141
142 to = &buf->_st[0];
143 from = (struct _fpxreg *) &fxsave->st_space[0];
144 for ( i = 0 ; i < 8 ; i++, to++, from++ ) {
145 if (__copy_to_user(to, from, sizeof(*to)))
146 return -1;
147 }
148 return 0;
149}
150
151int restore_i387_ia32(struct task_struct *tsk, struct _fpstate_ia32 __user *buf, int fsave)
152{
153 clear_fpu(tsk);
154 if (!fsave) {
155 if (__copy_from_user(&tsk->thread.i387.fxsave,
156 &buf->_fxsr_env[0],
157 sizeof(struct i387_fxsave_struct)))
158 return -1;
159 tsk->thread.i387.fxsave.mxcsr &= mxcsr_feature_mask;
160 set_stopped_child_used_math(tsk);
161 }
162 return convert_fxsr_from_user(&tsk->thread.i387.fxsave, buf);
163}
164
165int save_i387_ia32(struct task_struct *tsk,
166 struct _fpstate_ia32 __user *buf,
167 struct pt_regs *regs,
168 int fsave)
169{
170 int err = 0;
171
172 init_fpu(tsk);
173 if (convert_fxsr_to_user(buf, &tsk->thread.i387.fxsave, regs, tsk))
174 return -1;
175 if (fsave)
176 return 0;
177 err |= __put_user(tsk->thread.i387.fxsave.swd, &buf->status);
178 if (fsave)
179 return err ? -1 : 1;
180 err |= __put_user(X86_FXSR_MAGIC, &buf->magic);
181 err |= __copy_to_user(&buf->_fxsr_env[0], &tsk->thread.i387.fxsave,
182 sizeof(struct i387_fxsave_struct));
183 return err ? -1 : 1;
184}
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