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74ba9207 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
1da177e4 LT |
2 | |
3 | /* | |
4 | NetWinder Floating Point Emulator | |
5 | (c) Rebel.com, 1998-1999 | |
6 | (c) Philip Blundell, 1998-1999 | |
7 | ||
8 | Direct questions, comments to Scott Bambrough <scottb@netwinder.org> | |
9 | ||
1da177e4 LT |
10 | */ |
11 | ||
12 | #include "fpa11.h" | |
13 | ||
14 | #include <linux/module.h> | |
49aea0fd | 15 | #include <linux/moduleparam.h> |
1da177e4 LT |
16 | |
17 | /* XXX */ | |
18 | #include <linux/errno.h> | |
19 | #include <linux/types.h> | |
20 | #include <linux/kernel.h> | |
21 | #include <linux/signal.h> | |
c3edc401 | 22 | #include <linux/sched/signal.h> |
1da177e4 | 23 | #include <linux/init.h> |
d6551e88 RK |
24 | |
25 | #include <asm/thread_notify.h> | |
1da177e4 LT |
26 | |
27 | #include "softfloat.h" | |
28 | #include "fpopcode.h" | |
29 | #include "fpmodule.h" | |
30 | #include "fpa11.inl" | |
31 | ||
32 | /* kernel symbols required for signal handling */ | |
33 | #ifdef CONFIG_FPE_NWFPE_XP | |
34 | #define NWFPE_BITS "extended" | |
35 | #else | |
36 | #define NWFPE_BITS "double" | |
37 | #endif | |
38 | ||
39 | #ifdef MODULE | |
40 | void fp_send_sig(unsigned long sig, struct task_struct *p, int priv); | |
41 | #else | |
42 | #define fp_send_sig send_sig | |
43 | #define kern_fp_enter fp_enter | |
44 | ||
45 | extern char fpe_type[]; | |
46 | #endif | |
47 | ||
d6551e88 RK |
48 | static int nwfpe_notify(struct notifier_block *self, unsigned long cmd, void *v) |
49 | { | |
50 | struct thread_info *thread = v; | |
51 | ||
52 | if (cmd == THREAD_NOTIFY_FLUSH) | |
53 | nwfpe_init_fpa(&thread->fpstate); | |
54 | ||
55 | return NOTIFY_DONE; | |
56 | } | |
57 | ||
58 | static struct notifier_block nwfpe_notifier_block = { | |
59 | .notifier_call = nwfpe_notify, | |
60 | }; | |
61 | ||
1da177e4 LT |
62 | /* kernel function prototypes required */ |
63 | void fp_setup(void); | |
64 | ||
65 | /* external declarations for saved kernel symbols */ | |
66 | extern void (*kern_fp_enter)(void); | |
1da177e4 LT |
67 | |
68 | /* Original value of fp_enter from kernel before patched by fpe_init. */ | |
69 | static void (*orig_fp_enter)(void); | |
1da177e4 LT |
70 | |
71 | /* forward declarations */ | |
72 | extern void nwfpe_enter(void); | |
73 | ||
74 | static int __init fpe_init(void) | |
75 | { | |
76 | if (sizeof(FPA11) > sizeof(union fp_state)) { | |
4ed89f22 | 77 | pr_err("nwfpe: bad structure size\n"); |
1da177e4 LT |
78 | return -EINVAL; |
79 | } | |
80 | ||
81 | if (sizeof(FPREG) != 12) { | |
4ed89f22 | 82 | pr_err("nwfpe: bad register size\n"); |
1da177e4 LT |
83 | return -EINVAL; |
84 | } | |
85 | if (fpe_type[0] && strcmp(fpe_type, "nwfpe")) | |
86 | return 0; | |
87 | ||
88 | /* Display title, version and copyright information. */ | |
8a2ab42b RK |
89 | pr_info("NetWinder Floating Point Emulator V0.97 (" |
90 | NWFPE_BITS " precision)\n"); | |
1da177e4 | 91 | |
d6551e88 RK |
92 | thread_register_notifier(&nwfpe_notifier_block); |
93 | ||
1da177e4 LT |
94 | /* Save pointer to the old FP handler and then patch ourselves in */ |
95 | orig_fp_enter = kern_fp_enter; | |
1da177e4 | 96 | kern_fp_enter = nwfpe_enter; |
1da177e4 LT |
97 | |
98 | return 0; | |
99 | } | |
100 | ||
101 | static void __exit fpe_exit(void) | |
102 | { | |
d6551e88 | 103 | thread_unregister_notifier(&nwfpe_notifier_block); |
1da177e4 LT |
104 | /* Restore the values we saved earlier. */ |
105 | kern_fp_enter = orig_fp_enter; | |
1da177e4 LT |
106 | } |
107 | ||
108 | /* | |
109 | ScottB: November 4, 1998 | |
110 | ||
111 | Moved this function out of softfloat-specialize into fpmodule.c. | |
112 | This effectively isolates all the changes required for integrating with the | |
113 | Linux kernel into fpmodule.c. Porting to NetBSD should only require modifying | |
114 | fpmodule.c to integrate with the NetBSD kernel (I hope!). | |
115 | ||
116 | [1/1/99: Not quite true any more unfortunately. There is Linux-specific | |
117 | code to access data in user space in some other source files at the | |
118 | moment (grep for get_user / put_user calls). --philb] | |
119 | ||
1da177e4 LT |
120 | This function is called by the SoftFloat routines to raise a floating |
121 | point exception. We check the trap enable byte in the FPSR, and raise | |
122 | a SIGFPE exception if necessary. If not the relevant bits in the | |
123 | cumulative exceptions flag byte are set and we return. | |
124 | */ | |
125 | ||
49aea0fd RK |
126 | #ifdef CONFIG_DEBUG_USER |
127 | /* By default, ignore inexact errors as there are far too many of them to log */ | |
128 | static int debug = ~BIT_IXC; | |
129 | #endif | |
130 | ||
1da177e4 LT |
131 | void float_raise(signed char flags) |
132 | { | |
133 | register unsigned int fpsr, cumulativeTraps; | |
134 | ||
135 | #ifdef CONFIG_DEBUG_USER | |
49aea0fd | 136 | if (flags & debug) |
f148af25 | 137 | printk(KERN_DEBUG |
d75f773c | 138 | "NWFPE: %s[%d] takes exception %08x at %ps from %08lx\n", |
f148af25 RP |
139 | current->comm, current->pid, flags, |
140 | __builtin_return_address(0), GET_USERREG()->ARM_pc); | |
1da177e4 LT |
141 | #endif |
142 | ||
1da177e4 LT |
143 | /* Read fpsr and initialize the cumulativeTraps. */ |
144 | fpsr = readFPSR(); | |
145 | cumulativeTraps = 0; | |
146 | ||
147 | /* For each type of exception, the cumulative trap exception bit is only | |
148 | set if the corresponding trap enable bit is not set. */ | |
149 | if ((!(fpsr & BIT_IXE)) && (flags & BIT_IXC)) | |
150 | cumulativeTraps |= BIT_IXC; | |
151 | if ((!(fpsr & BIT_UFE)) && (flags & BIT_UFC)) | |
152 | cumulativeTraps |= BIT_UFC; | |
153 | if ((!(fpsr & BIT_OFE)) && (flags & BIT_OFC)) | |
154 | cumulativeTraps |= BIT_OFC; | |
155 | if ((!(fpsr & BIT_DZE)) && (flags & BIT_DZC)) | |
156 | cumulativeTraps |= BIT_DZC; | |
157 | if ((!(fpsr & BIT_IOE)) && (flags & BIT_IOC)) | |
158 | cumulativeTraps |= BIT_IOC; | |
159 | ||
160 | /* Set the cumulative exceptions flags. */ | |
161 | if (cumulativeTraps) | |
162 | writeFPSR(fpsr | cumulativeTraps); | |
163 | ||
164 | /* Raise an exception if necessary. */ | |
165 | if (fpsr & (flags << 16)) | |
166 | fp_send_sig(SIGFPE, current, 1); | |
167 | } | |
168 | ||
169 | module_init(fpe_init); | |
170 | module_exit(fpe_exit); | |
171 | ||
172 | MODULE_AUTHOR("Scott Bambrough <scottb@rebel.com>"); | |
173 | MODULE_DESCRIPTION("NWFPE floating point emulator (" NWFPE_BITS " precision)"); | |
174 | MODULE_LICENSE("GPL"); | |
49aea0fd RK |
175 | |
176 | #ifdef CONFIG_DEBUG_USER | |
177 | module_param(debug, int, 0644); | |
178 | #endif |