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1da177e4 LT |
1 | /* |
2 | * include/asm-x86_64/i387.h | |
3 | * | |
4 | * Copyright (C) 1994 Linus Torvalds | |
5 | * | |
6 | * Pentium III FXSR, SSE support | |
7 | * General FPU state handling cleanups | |
8 | * Gareth Hughes <gareth@valinux.com>, May 2000 | |
9 | * x86-64 work by Andi Kleen 2002 | |
10 | */ | |
11 | ||
12 | #ifndef __ASM_X86_64_I387_H | |
13 | #define __ASM_X86_64_I387_H | |
14 | ||
15 | #include <linux/sched.h> | |
16 | #include <asm/processor.h> | |
17 | #include <asm/sigcontext.h> | |
18 | #include <asm/user.h> | |
19 | #include <asm/thread_info.h> | |
20 | #include <asm/uaccess.h> | |
21 | ||
22 | extern void fpu_init(void); | |
23 | extern unsigned int mxcsr_feature_mask; | |
24 | extern void mxcsr_feature_mask_init(void); | |
25 | extern void init_fpu(struct task_struct *child); | |
26 | extern int save_i387(struct _fpstate __user *buf); | |
27 | ||
28 | /* | |
29 | * FPU lazy state save handling... | |
30 | */ | |
31 | ||
32 | #define unlazy_fpu(tsk) do { \ | |
e4f17c43 | 33 | if (task_thread_info(tsk)->status & TS_USEDFPU) \ |
1da177e4 LT |
34 | save_init_fpu(tsk); \ |
35 | } while (0) | |
36 | ||
37 | /* Ignore delayed exceptions from user space */ | |
38 | static inline void tolerant_fwait(void) | |
39 | { | |
40 | asm volatile("1: fwait\n" | |
41 | "2:\n" | |
42 | " .section __ex_table,\"a\"\n" | |
43 | " .align 8\n" | |
44 | " .quad 1b,2b\n" | |
45 | " .previous\n"); | |
46 | } | |
47 | ||
48 | #define clear_fpu(tsk) do { \ | |
e4f17c43 | 49 | if (task_thread_info(tsk)->status & TS_USEDFPU) { \ |
1da177e4 | 50 | tolerant_fwait(); \ |
e4f17c43 | 51 | task_thread_info(tsk)->status &= ~TS_USEDFPU; \ |
1da177e4 LT |
52 | stts(); \ |
53 | } \ | |
54 | } while (0) | |
55 | ||
56 | /* | |
57 | * ptrace request handers... | |
58 | */ | |
59 | extern int get_fpregs(struct user_i387_struct __user *buf, | |
60 | struct task_struct *tsk); | |
61 | extern int set_fpregs(struct task_struct *tsk, | |
62 | struct user_i387_struct __user *buf); | |
63 | ||
64 | /* | |
65 | * i387 state interaction | |
66 | */ | |
67 | #define get_fpu_mxcsr(t) ((t)->thread.i387.fxsave.mxcsr) | |
68 | #define get_fpu_cwd(t) ((t)->thread.i387.fxsave.cwd) | |
69 | #define get_fpu_fxsr_twd(t) ((t)->thread.i387.fxsave.twd) | |
70 | #define get_fpu_swd(t) ((t)->thread.i387.fxsave.swd) | |
71 | #define set_fpu_cwd(t,val) ((t)->thread.i387.fxsave.cwd = (val)) | |
72 | #define set_fpu_swd(t,val) ((t)->thread.i387.fxsave.swd = (val)) | |
73 | #define set_fpu_fxsr_twd(t,val) ((t)->thread.i387.fxsave.twd = (val)) | |
74 | ||
75 | static inline int restore_fpu_checking(struct i387_fxsave_struct *fx) | |
76 | { | |
77 | int err; | |
7180d4fb JB |
78 | |
79 | asm volatile("1: rex64/fxrstor (%[fx])\n\t" | |
1da177e4 LT |
80 | "2:\n" |
81 | ".section .fixup,\"ax\"\n" | |
82 | "3: movl $-1,%[err]\n" | |
83 | " jmp 2b\n" | |
84 | ".previous\n" | |
85 | ".section __ex_table,\"a\"\n" | |
86 | " .align 8\n" | |
87 | " .quad 1b,3b\n" | |
88 | ".previous" | |
89 | : [err] "=r" (err) | |
7180d4fb JB |
90 | #if 0 /* See comment in __fxsave_clear() below. */ |
91 | : [fx] "r" (fx), "m" (*fx), "0" (0)); | |
92 | #else | |
93 | : [fx] "cdaSDb" (fx), "m" (*fx), "0" (0)); | |
94 | #endif | |
1da177e4 LT |
95 | if (unlikely(err)) |
96 | init_fpu(current); | |
97 | return err; | |
98 | } | |
99 | ||
100 | static inline int save_i387_checking(struct i387_fxsave_struct __user *fx) | |
101 | { | |
102 | int err; | |
7180d4fb JB |
103 | |
104 | asm volatile("1: rex64/fxsave (%[fx])\n\t" | |
1da177e4 LT |
105 | "2:\n" |
106 | ".section .fixup,\"ax\"\n" | |
107 | "3: movl $-1,%[err]\n" | |
108 | " jmp 2b\n" | |
109 | ".previous\n" | |
110 | ".section __ex_table,\"a\"\n" | |
111 | " .align 8\n" | |
112 | " .quad 1b,3b\n" | |
113 | ".previous" | |
7180d4fb JB |
114 | : [err] "=r" (err), "=m" (*fx) |
115 | #if 0 /* See comment in __fxsave_clear() below. */ | |
116 | : [fx] "r" (fx), "0" (0)); | |
117 | #else | |
118 | : [fx] "cdaSDb" (fx), "0" (0)); | |
119 | #endif | |
1da177e4 LT |
120 | if (unlikely(err)) |
121 | __clear_user(fx, sizeof(struct i387_fxsave_struct)); | |
122 | return err; | |
123 | } | |
124 | ||
7180d4fb JB |
125 | static inline void __fxsave_clear(struct task_struct *tsk) |
126 | { | |
127 | /* Using "rex64; fxsave %0" is broken because, if the memory operand | |
128 | uses any extended registers for addressing, a second REX prefix | |
129 | will be generated (to the assembler, rex64 followed by semicolon | |
130 | is a separate instruction), and hence the 64-bitness is lost. */ | |
131 | #if 0 | |
132 | /* Using "fxsaveq %0" would be the ideal choice, but is only supported | |
133 | starting with gas 2.16. */ | |
134 | __asm__ __volatile__("fxsaveq %0" | |
135 | : "=m" (tsk->thread.i387.fxsave)); | |
136 | #elif 0 | |
137 | /* Using, as a workaround, the properly prefixed form below isn't | |
138 | accepted by any binutils version so far released, complaining that | |
139 | the same type of prefix is used twice if an extended register is | |
140 | needed for addressing (fix submitted to mainline 2005-11-21). */ | |
141 | __asm__ __volatile__("rex64/fxsave %0" | |
142 | : "=m" (tsk->thread.i387.fxsave)); | |
143 | #else | |
144 | /* This, however, we can work around by forcing the compiler to select | |
145 | an addressing mode that doesn't require extended registers. */ | |
146 | __asm__ __volatile__("rex64/fxsave %P2(%1)" | |
147 | : "=m" (tsk->thread.i387.fxsave) | |
148 | : "cdaSDb" (tsk), | |
149 | "i" (offsetof(__typeof__(*tsk), | |
150 | thread.i387.fxsave))); | |
151 | #endif | |
152 | __asm__ __volatile__("fnclex"); | |
153 | } | |
154 | ||
1da177e4 LT |
155 | static inline void kernel_fpu_begin(void) |
156 | { | |
157 | struct thread_info *me = current_thread_info(); | |
158 | preempt_disable(); | |
7180d4fb JB |
159 | if (me->status & TS_USEDFPU) { |
160 | __fxsave_clear(me->task); | |
1da177e4 LT |
161 | me->status &= ~TS_USEDFPU; |
162 | return; | |
163 | } | |
164 | clts(); | |
165 | } | |
166 | ||
167 | static inline void kernel_fpu_end(void) | |
168 | { | |
169 | stts(); | |
170 | preempt_enable(); | |
171 | } | |
172 | ||
e4f17c43 | 173 | static inline void save_init_fpu(struct task_struct *tsk) |
1da177e4 | 174 | { |
7180d4fb | 175 | __fxsave_clear(tsk); |
e4f17c43 | 176 | task_thread_info(tsk)->status &= ~TS_USEDFPU; |
1da177e4 LT |
177 | stts(); |
178 | } | |
179 | ||
180 | /* | |
181 | * This restores directly out of user space. Exceptions are handled. | |
182 | */ | |
183 | static inline int restore_i387(struct _fpstate __user *buf) | |
184 | { | |
185 | return restore_fpu_checking((__force struct i387_fxsave_struct *)buf); | |
186 | } | |
187 | ||
188 | #endif /* __ASM_X86_64_I387_H */ |