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 52void 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 57extern char fpe_type[]; 58#endif 59 60static 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 70static struct notifier_block nwfpe_notifier_block = { 71 .notifier_call = nwfpe_notify, 72}; 73 74/* kernel function prototypes required */ 75void fp_setup(void); 76 77/* external declarations for saved kernel symbols */ 78extern void (*kern_fp_enter)(void); 79 80/* Original value of fp_enter from kernel before patched by fpe_init. */ 81static void (*orig_fp_enter)(void); 82 83/* forward declarations */ 84extern void nwfpe_enter(void); 85 86static int __init fpe_init(void) 87{ 88 if (sizeof(FPA11) > sizeof(union fp_state)) { 89 printk(KERN_ERR "nwfpe: bad structure size\n"); 90 return -EINVAL; 91 } 92 93 if (sizeof(FPREG) != 12) { 94 printk(KERN_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 printk(KERN_WARNING "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 113static 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/* 121ScottB: November 4, 1998 122 123Moved this function out of softfloat-specialize into fpmodule.c. 124This effectively isolates all the changes required for integrating with the 125Linux kernel into fpmodule.c. Porting to NetBSD should only require modifying 126fpmodule.c to integrate with the NetBSD kernel (I hope!). 127 128[1/1/99: Not quite true any more unfortunately. There is Linux-specific 129code to access data in user space in some other source files at the 130moment (grep for get_user / put_user calls). --philb] 131 132This function is called by the SoftFloat routines to raise a floating 133point exception. We check the trap enable byte in the FPSR, and raise 134a SIGFPE exception if necessary. If not the relevant bits in the 135cumulative 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 */ 140static int debug = ~BIT_IXC; 141#endif 142 143void 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 %p 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 181module_init(fpe_init); 182module_exit(fpe_exit); 183 184MODULE_AUTHOR("Scott Bambrough <scottb@rebel.com>"); 185MODULE_DESCRIPTION("NWFPE floating point emulator (" NWFPE_BITS " precision)"); 186MODULE_LICENSE("GPL"); 187 188#ifdef CONFIG_DEBUG_USER 189module_param(debug, int, 0644); 190#endif 191