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 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> 35 36 #include <asm/thread_notify.h> 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 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 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); 78 79 /* Original value of fp_enter from kernel before patched by fpe_init. */ 80 static void (*orig_fp_enter)(void); 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"); 102 103 thread_register_notifier(&nwfpe_notifier_block); 104 105 /* Save pointer to the old FP handler and then patch ourselves in */ 106 orig_fp_enter = kern_fp_enter; 107 kern_fp_enter = nwfpe_enter; 108 109 return 0; 110 } 111 112 static void __exit fpe_exit(void) 113 { 114 thread_unregister_notifier(&nwfpe_notifier_block); 115 /* Restore the values we saved earlier. */ 116 kern_fp_enter = orig_fp_enter; 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] 130 131 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 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); 148 #endif 149 150 /* 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"); 182