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1da177e4 LT |
1 | |
2 | /* | |
3 | NetWinder Floating Point Emulator | |
4 | (c) Rebel.com, 1998-1999 | |
5 | (c) Philip Blundell, 1998-1999 | |
6 | ||
7 | Direct questions, comments to Scott Bambrough <scottb@netwinder.org> | |
8 | ||
9 | This program is free software; you can redistribute it and/or modify | |
10 | it under the terms of the GNU General Public License as published by | |
11 | the Free Software Foundation; either version 2 of the License, or | |
12 | (at your option) any later version. | |
13 | ||
14 | This program is distributed in the hope that it will be useful, | |
15 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | GNU General Public License for more details. | |
18 | ||
19 | You should have received a copy of the GNU General Public License | |
20 | along with this program; if not, write to the Free Software | |
21 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
22 | */ | |
23 | ||
24 | #include "fpa11.h" | |
25 | ||
26 | #include <linux/module.h> | |
1da177e4 LT |
27 | |
28 | /* XXX */ | |
29 | #include <linux/errno.h> | |
30 | #include <linux/types.h> | |
31 | #include <linux/kernel.h> | |
32 | #include <linux/signal.h> | |
33 | #include <linux/sched.h> | |
34 | #include <linux/init.h> | |
d6551e88 RK |
35 | |
36 | #include <asm/thread_notify.h> | |
1da177e4 LT |
37 | |
38 | #include "softfloat.h" | |
39 | #include "fpopcode.h" | |
40 | #include "fpmodule.h" | |
41 | #include "fpa11.inl" | |
42 | ||
43 | /* kernel symbols required for signal handling */ | |
44 | #ifdef CONFIG_FPE_NWFPE_XP | |
45 | #define NWFPE_BITS "extended" | |
46 | #else | |
47 | #define NWFPE_BITS "double" | |
48 | #endif | |
49 | ||
50 | #ifdef MODULE | |
51 | void fp_send_sig(unsigned long sig, struct task_struct *p, int priv); | |
52 | #else | |
53 | #define fp_send_sig send_sig | |
54 | #define kern_fp_enter fp_enter | |
55 | ||
56 | extern char fpe_type[]; | |
57 | #endif | |
58 | ||
d6551e88 RK |
59 | static int nwfpe_notify(struct notifier_block *self, unsigned long cmd, void *v) |
60 | { | |
61 | struct thread_info *thread = v; | |
62 | ||
63 | if (cmd == THREAD_NOTIFY_FLUSH) | |
64 | nwfpe_init_fpa(&thread->fpstate); | |
65 | ||
66 | return NOTIFY_DONE; | |
67 | } | |
68 | ||
69 | static struct notifier_block nwfpe_notifier_block = { | |
70 | .notifier_call = nwfpe_notify, | |
71 | }; | |
72 | ||
1da177e4 LT |
73 | /* kernel function prototypes required */ |
74 | void fp_setup(void); | |
75 | ||
76 | /* external declarations for saved kernel symbols */ | |
77 | extern void (*kern_fp_enter)(void); | |
1da177e4 LT |
78 | |
79 | /* Original value of fp_enter from kernel before patched by fpe_init. */ | |
80 | static void (*orig_fp_enter)(void); | |
1da177e4 LT |
81 | |
82 | /* forward declarations */ | |
83 | extern void nwfpe_enter(void); | |
84 | ||
85 | static int __init fpe_init(void) | |
86 | { | |
87 | if (sizeof(FPA11) > sizeof(union fp_state)) { | |
88 | printk(KERN_ERR "nwfpe: bad structure size\n"); | |
89 | return -EINVAL; | |
90 | } | |
91 | ||
92 | if (sizeof(FPREG) != 12) { | |
93 | printk(KERN_ERR "nwfpe: bad register size\n"); | |
94 | return -EINVAL; | |
95 | } | |
96 | if (fpe_type[0] && strcmp(fpe_type, "nwfpe")) | |
97 | return 0; | |
98 | ||
99 | /* Display title, version and copyright information. */ | |
100 | printk(KERN_WARNING "NetWinder Floating Point Emulator V0.97 (" | |
101 | NWFPE_BITS " precision)\n"); | |
102 | ||
d6551e88 RK |
103 | thread_register_notifier(&nwfpe_notifier_block); |
104 | ||
1da177e4 LT |
105 | /* Save pointer to the old FP handler and then patch ourselves in */ |
106 | orig_fp_enter = kern_fp_enter; | |
1da177e4 | 107 | kern_fp_enter = nwfpe_enter; |
1da177e4 LT |
108 | |
109 | return 0; | |
110 | } | |
111 | ||
112 | static void __exit fpe_exit(void) | |
113 | { | |
d6551e88 | 114 | thread_unregister_notifier(&nwfpe_notifier_block); |
1da177e4 LT |
115 | /* Restore the values we saved earlier. */ |
116 | kern_fp_enter = orig_fp_enter; | |
1da177e4 LT |
117 | } |
118 | ||
119 | /* | |
120 | ScottB: November 4, 1998 | |
121 | ||
122 | Moved this function out of softfloat-specialize into fpmodule.c. | |
123 | This effectively isolates all the changes required for integrating with the | |
124 | Linux kernel into fpmodule.c. Porting to NetBSD should only require modifying | |
125 | fpmodule.c to integrate with the NetBSD kernel (I hope!). | |
126 | ||
127 | [1/1/99: Not quite true any more unfortunately. There is Linux-specific | |
128 | code to access data in user space in some other source files at the | |
129 | moment (grep for get_user / put_user calls). --philb] | |
130 | ||
1da177e4 LT |
131 | This function is called by the SoftFloat routines to raise a floating |
132 | point exception. We check the trap enable byte in the FPSR, and raise | |
133 | a SIGFPE exception if necessary. If not the relevant bits in the | |
134 | cumulative exceptions flag byte are set and we return. | |
135 | */ | |
136 | ||
137 | void float_raise(signed char flags) | |
138 | { | |
139 | register unsigned int fpsr, cumulativeTraps; | |
140 | ||
141 | #ifdef CONFIG_DEBUG_USER | |
f148af25 RP |
142 | /* Ignore inexact errors as there are far too many of them to log */ |
143 | if (flags & ~BIT_IXC) | |
144 | printk(KERN_DEBUG | |
145 | "NWFPE: %s[%d] takes exception %08x at %p from %08lx\n", | |
146 | current->comm, current->pid, flags, | |
147 | __builtin_return_address(0), GET_USERREG()->ARM_pc); | |
1da177e4 LT |
148 | #endif |
149 | ||
1da177e4 LT |
150 | /* Read fpsr and initialize the cumulativeTraps. */ |
151 | fpsr = readFPSR(); | |
152 | cumulativeTraps = 0; | |
153 | ||
154 | /* For each type of exception, the cumulative trap exception bit is only | |
155 | set if the corresponding trap enable bit is not set. */ | |
156 | if ((!(fpsr & BIT_IXE)) && (flags & BIT_IXC)) | |
157 | cumulativeTraps |= BIT_IXC; | |
158 | if ((!(fpsr & BIT_UFE)) && (flags & BIT_UFC)) | |
159 | cumulativeTraps |= BIT_UFC; | |
160 | if ((!(fpsr & BIT_OFE)) && (flags & BIT_OFC)) | |
161 | cumulativeTraps |= BIT_OFC; | |
162 | if ((!(fpsr & BIT_DZE)) && (flags & BIT_DZC)) | |
163 | cumulativeTraps |= BIT_DZC; | |
164 | if ((!(fpsr & BIT_IOE)) && (flags & BIT_IOC)) | |
165 | cumulativeTraps |= BIT_IOC; | |
166 | ||
167 | /* Set the cumulative exceptions flags. */ | |
168 | if (cumulativeTraps) | |
169 | writeFPSR(fpsr | cumulativeTraps); | |
170 | ||
171 | /* Raise an exception if necessary. */ | |
172 | if (fpsr & (flags << 16)) | |
173 | fp_send_sig(SIGFPE, current, 1); | |
174 | } | |
175 | ||
176 | module_init(fpe_init); | |
177 | module_exit(fpe_exit); | |
178 | ||
179 | MODULE_AUTHOR("Scott Bambrough <scottb@rebel.com>"); | |
180 | MODULE_DESCRIPTION("NWFPE floating point emulator (" NWFPE_BITS " precision)"); | |
181 | MODULE_LICENSE("GPL"); |