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> 27 #include <linux/moduleparam.h> 28 29 /* XXX */ 30 #include <linux/errno.h> 31 #include <linux/types.h> 32 #include <linux/kernel.h> 33 #include <linux/signal.h> 34 #include <linux/sched.h> 35 #include <linux/init.h> 36 37 #include <asm/thread_notify.h> 38 39 #include "softfloat.h" 40 #include "fpopcode.h" 41 #include "fpmodule.h" 42 #include "fpa11.inl" 43 44 /* kernel symbols required for signal handling */ 45 #ifdef CONFIG_FPE_NWFPE_XP 46 #define NWFPE_BITS "extended" 47 #else 48 #define NWFPE_BITS "double" 49 #endif 50 51 #ifdef MODULE 52 void fp_send_sig(unsigned long sig, struct task_struct *p, int priv); 53 #else 54 #define fp_send_sig send_sig 55 #define kern_fp_enter fp_enter 56 57 extern char fpe_type[]; 58 #endif 59 60 static int nwfpe_notify(struct notifier_block *self, unsigned long cmd, void *v) 61 { 62 struct thread_info *thread = v; 63 64 if (cmd == THREAD_NOTIFY_FLUSH) 65 nwfpe_init_fpa(&thread->fpstate); 66 67 return NOTIFY_DONE; 68 } 69 70 static struct notifier_block nwfpe_notifier_block = { 71 .notifier_call = nwfpe_notify, 72 }; 73 74 /* kernel function prototypes required */ 75 void fp_setup(void); 76 77 /* external declarations for saved kernel symbols */ 78 extern void (*kern_fp_enter)(void); 79 80 /* Original value of fp_enter from kernel before patched by fpe_init. */ 81 static void (*orig_fp_enter)(void); 82 83 /* forward declarations */ 84 extern void nwfpe_enter(void); 85 86 static int __init fpe_init(void) 87 { 88 if (sizeof(FPA11) > sizeof(union fp_state)) { 89 pr_err("nwfpe: bad structure size\n"); 90 return -EINVAL; 91 } 92 93 if (sizeof(FPREG) != 12) { 94 pr_err("nwfpe: bad register size\n"); 95 return -EINVAL; 96 } 97 if (fpe_type[0] && strcmp(fpe_type, "nwfpe")) 98 return 0; 99 100 /* Display title, version and copyright information. */ 101 pr_info("NetWinder Floating Point Emulator V0.97 (" 102 NWFPE_BITS " precision)\n"); 103 104 thread_register_notifier(&nwfpe_notifier_block); 105 106 /* Save pointer to the old FP handler and then patch ourselves in */ 107 orig_fp_enter = kern_fp_enter; 108 kern_fp_enter = nwfpe_enter; 109 110 return 0; 111 } 112 113 static void __exit fpe_exit(void) 114 { 115 thread_unregister_notifier(&nwfpe_notifier_block); 116 /* Restore the values we saved earlier. */ 117 kern_fp_enter = orig_fp_enter; 118 } 119 120 /* 121 ScottB: November 4, 1998 122 123 Moved this function out of softfloat-specialize into fpmodule.c. 124 This effectively isolates all the changes required for integrating with the 125 Linux kernel into fpmodule.c. Porting to NetBSD should only require modifying 126 fpmodule.c to integrate with the NetBSD kernel (I hope!). 127 128 [1/1/99: Not quite true any more unfortunately. There is Linux-specific 129 code to access data in user space in some other source files at the 130 moment (grep for get_user / put_user calls). --philb] 131 132 This function is called by the SoftFloat routines to raise a floating 133 point exception. We check the trap enable byte in the FPSR, and raise 134 a SIGFPE exception if necessary. If not the relevant bits in the 135 cumulative exceptions flag byte are set and we return. 136 */ 137 138 #ifdef CONFIG_DEBUG_USER 139 /* By default, ignore inexact errors as there are far too many of them to log */ 140 static int debug = ~BIT_IXC; 141 #endif 142 143 void float_raise(signed char flags) 144 { 145 register unsigned int fpsr, cumulativeTraps; 146 147 #ifdef CONFIG_DEBUG_USER 148 if (flags & debug) 149 printk(KERN_DEBUG 150 "NWFPE: %s[%d] takes exception %08x at %pf from %08lx\n", 151 current->comm, current->pid, flags, 152 __builtin_return_address(0), GET_USERREG()->ARM_pc); 153 #endif 154 155 /* Read fpsr and initialize the cumulativeTraps. */ 156 fpsr = readFPSR(); 157 cumulativeTraps = 0; 158 159 /* For each type of exception, the cumulative trap exception bit is only 160 set if the corresponding trap enable bit is not set. */ 161 if ((!(fpsr & BIT_IXE)) && (flags & BIT_IXC)) 162 cumulativeTraps |= BIT_IXC; 163 if ((!(fpsr & BIT_UFE)) && (flags & BIT_UFC)) 164 cumulativeTraps |= BIT_UFC; 165 if ((!(fpsr & BIT_OFE)) && (flags & BIT_OFC)) 166 cumulativeTraps |= BIT_OFC; 167 if ((!(fpsr & BIT_DZE)) && (flags & BIT_DZC)) 168 cumulativeTraps |= BIT_DZC; 169 if ((!(fpsr & BIT_IOE)) && (flags & BIT_IOC)) 170 cumulativeTraps |= BIT_IOC; 171 172 /* Set the cumulative exceptions flags. */ 173 if (cumulativeTraps) 174 writeFPSR(fpsr | cumulativeTraps); 175 176 /* Raise an exception if necessary. */ 177 if (fpsr & (flags << 16)) 178 fp_send_sig(SIGFPE, current, 1); 179 } 180 181 module_init(fpe_init); 182 module_exit(fpe_exit); 183 184 MODULE_AUTHOR("Scott Bambrough <scottb@rebel.com>"); 185 MODULE_DESCRIPTION("NWFPE floating point emulator (" NWFPE_BITS " precision)"); 186 MODULE_LICENSE("GPL"); 187 188 #ifdef CONFIG_DEBUG_USER 189 module_param(debug, int, 0644); 190 #endif 191