summaryrefslogtreecommitdiff
path: root/include/asm-x86/i387_32.h
blob: 9ac2502cdd3d30d0ee0f8fe8861f8aba307d7862 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
/*
 * Copyright (C) 1994 Linus Torvalds
 *
 * Pentium III FXSR, SSE support
 * General FPU state handling cleanups
 *	Gareth Hughes <gareth@valinux.com>, May 2000
 */

#ifndef __ASM_I386_I387_H
#define __ASM_I386_I387_H

#include <linux/sched.h>
#include <linux/init.h>
#include <linux/kernel_stat.h>
#include <asm/processor.h>
#include <asm/sigcontext.h>
#include <asm/user.h>

extern void mxcsr_feature_mask_init(void);
extern void init_fpu(struct task_struct *);

/*
 * FPU lazy state save handling...
 */

/*
 * The "nop" is needed to make the instructions the same
 * length.
 */
#define restore_fpu(tsk)			\
	alternative_input(			\
		"nop ; frstor %1",		\
		"fxrstor %1",			\
		X86_FEATURE_FXSR,		\
		"m" ((tsk)->thread.i387.fxsave))

extern void kernel_fpu_begin(void);
#define kernel_fpu_end() do { stts(); preempt_enable(); } while(0)

/* We need a safe address that is cheap to find and that is already
   in L1 during context switch. The best choices are unfortunately
   different for UP and SMP */
#ifdef CONFIG_SMP
#define safe_address (__per_cpu_offset[0])
#else
#define safe_address (kstat_cpu(0).cpustat.user)
#endif

/*
 * These must be called with preempt disabled
 */
static inline void __save_init_fpu( struct task_struct *tsk )
{
	/* Use more nops than strictly needed in case the compiler
	   varies code */
	alternative_input(
		"fnsave %[fx] ;fwait;" GENERIC_NOP8 GENERIC_NOP4,
		"fxsave %[fx]\n"
		"bt $7,%[fsw] ; jnc 1f ; fnclex\n1:",
		X86_FEATURE_FXSR,
		[fx] "m" (tsk->thread.i387.fxsave),
		[fsw] "m" (tsk->thread.i387.fxsave.swd) : "memory");
	/* AMD K7/K8 CPUs don't save/restore FDP/FIP/FOP unless an exception
	   is pending.  Clear the x87 state here by setting it to fixed
   	   values. safe_address is a random variable that should be in L1 */
	alternative_input(
		GENERIC_NOP8 GENERIC_NOP2,
		"emms\n\t"	  	/* clear stack tags */
		"fildl %[addr]", 	/* set F?P to defined value */
		X86_FEATURE_FXSAVE_LEAK,
		[addr] "m" (safe_address));
	task_thread_info(tsk)->status &= ~TS_USEDFPU;
}

#define __unlazy_fpu( tsk ) do {				\
	if (task_thread_info(tsk)->status & TS_USEDFPU) {	\
		__save_init_fpu(tsk);				\
		stts();						\
	} else							\
		tsk->fpu_counter = 0;				\
} while (0)

#define __clear_fpu( tsk )					\
do {								\
	if (task_thread_info(tsk)->status & TS_USEDFPU) {	\
		asm volatile("fnclex ; fwait");			\
		task_thread_info(tsk)->status &= ~TS_USEDFPU;	\
		stts();						\
	}							\
} while (0)


/*
 * These disable preemption on their own and are safe
 */
static inline void save_init_fpu( struct task_struct *tsk )
{
	preempt_disable();
	__save_init_fpu(tsk);
	stts();
	preempt_enable();
}

#define unlazy_fpu( tsk ) do {	\
	preempt_disable();	\
	__unlazy_fpu(tsk);	\
	preempt_enable();	\
} while (0)

#define clear_fpu( tsk ) do {	\
	preempt_disable();	\
	__clear_fpu( tsk );	\
	preempt_enable();	\
} while (0)

/*
 * FPU state interaction...
 */
extern unsigned short get_fpu_cwd( struct task_struct *tsk );
extern unsigned short get_fpu_swd( struct task_struct *tsk );
extern unsigned short get_fpu_mxcsr( struct task_struct *tsk );
extern asmlinkage void math_state_restore(void);

/*
 * Signal frame handlers...
 */
extern int save_i387( struct _fpstate __user *buf );
extern int restore_i387( struct _fpstate __user *buf );

/*
 * ptrace request handers...
 */
extern int get_fpregs( struct user_i387_struct __user *buf,
		       struct task_struct *tsk );
extern int set_fpregs( struct task_struct *tsk,
		       struct user_i387_struct __user *buf );

extern int get_fpxregs( struct user_fxsr_struct __user *buf,
			struct task_struct *tsk );
extern int set_fpxregs( struct task_struct *tsk,
			struct user_fxsr_struct __user *buf );

/*
 * FPU state for core dumps...
 */
extern int dump_fpu( struct pt_regs *regs,
		     struct user_i387_struct *fpu );

#endif /* __ASM_I386_I387_H */