arch/arm/nwfpe/fpmodule.c

   1 /*
   2     NetWinder Floating Point Emulator
   3     (c) Rebel.com, 1998-1999
   4     (c) Philip Blundell, 1998-1999
   5
   6     Direct questions, comments to Scott Bambrough <scottb@netwinder.org>
   7
   8     This program is free software; you can redistribute it and/or modify
   9     it under the terms of the GNU General Public License as published by
  10     the Free Software Foundation; either version 2 of the License, or
  11     (at your option) any later version.
  12
  13     This program is distributed in the hope that it will be useful,
  14     but WITHOUT ANY WARRANTY; without even the implied warranty of
  15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16     GNU General Public License for more details.
  17
  18     You should have received a copy of the GNU General Public License
  19     along with this program; if not, write to the Free Software
  20     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21 */
  22
  23 #include "config.h"
  24
  25 #ifdef MODULE
  26 #include <linux/module.h>
  27 #include <linux/version.h>
  28 #else
  29 #define MOD_INC_USE_COUNT
  30 #define MOD_DEC_USE_COUNT
  31 #endif
  32
  33 /* XXX */
  34 #include <linux/types.h>
  35 #include <linux/kernel.h>
  36 #include <linux/signal.h>
  37 #include <linux/sched.h>
  38 #include <linux/mm.h>
  39 #include <linux/init.h>
  40 #include <linux/spinlock.h>
  41
  42 #include <asm/system.h>
  43 #include <asm/uaccess.h>
  44 #include <asm/io.h>
  45 #include <asm/atomic.h>
  46 #include <asm/pgtable.h>
  47 /* XXX */
  48
  49 #include "softfloat.h"
  50 #include "fpopcode.h"
  51 #include "fpmodule.h"
  52 #include "fpa11.h"
  53 #include "fpa11.inl"
  54
  55 /* external data */
  56 extern FPA11 *fpa11;
  57
  58 /* kernel symbols required for signal handling */
  59 typedef struct task_struct*     PTASK;
  60
  61 #ifdef MODULE
  62 int fp_printk(const char *,...);
  63 void fp_send_sig(unsigned long sig, PTASK p, int priv);
  64 #if LINUX_VERSION_CODE > 0x20115
  65 MODULE_AUTHOR("Scott Bambrough <scottb@netwinder.org>");
  66 MODULE_DESCRIPTION("NWFPE floating point emulator");
  67 #endif
  68
  69 #else
  70 #define fp_printk       printk
  71 #define fp_send_sig     send_sig
  72 #define kern_fp_enter   fp_enter
  73 #endif
  74
  75 /* kernel function prototypes required */
  76 void C_SYMBOL_NAME(fp_setup)(void);
  77
  78 /* external declarations for saved kernel symbols */
  79 extern unsigned int C_SYMBOL_NAME(kern_fp_enter);
  80
  81 /* forward declarations */
  82 extern void nwfpe_enter(void);
  83
  84 /* Original value of fp_enter from kernel before patched by fpe_init. */
  85 static unsigned int orig_fp_enter;
  86
  87 /* Address of user registers on the kernel stack. */
  88 unsigned int *userRegisters;
  89
  90 void __init C_SYMBOL_NAME(fpe_version)(void)
  91 {
  92   static const char szTitle[] = "<4>NetWinder Floating Point Emulator ";
  93   static const char szVersion[] = "V0.94.1 ";
  94   static const char szCopyright[] = "(c) 1998-1999 Rebel.com\n";
  95   C_SYMBOL_NAME(fp_printk)(szTitle);
  96   C_SYMBOL_NAME(fp_printk)(szVersion);
  97   C_SYMBOL_NAME(fp_printk)(szCopyright);
  98 }
  99
 100 int __init fpe_init(void)
 101 {
 102   /* Display title, version and copyright information. */
 103   C_SYMBOL_NAME(fpe_version)();
 104
 105   /* Save pointer to the old FP handler and then patch ourselves in */
 106   orig_fp_enter = C_SYMBOL_NAME(kern_fp_enter);
 107   C_SYMBOL_NAME(kern_fp_enter) = (unsigned int)C_SYMBOL_NAME(nwfpe_enter);
 108
 109   return 0;
 110 }
 111
 112 #ifdef MODULE
 113 int init_module(void)
 114 {
 115   return(fpe_init());
 116 }
 117
 118 void cleanup_module(void)
 119 {
 120   /* Restore the values we saved earlier. */
 121   C_SYMBOL_NAME(kern_fp_enter) = orig_fp_enter;
 122 }
 123 #endif
 124
 125 #define _ARM_pc 60
 126 #define _ARM_cpsr 64
 127
 128 /*
 129 ScottB:  November 4, 1998
 130
 131 Moved this function out of softfloat-specialize into fpmodule.c.
 132 This effectively isolates all the changes required for integrating with the
 133 Linux kernel into fpmodule.c.  Porting to NetBSD should only require modifying
 134 fpmodule.c to integrate with the NetBSD kernel (I hope!).
 135
 136 [1/1/99: Not quite true any more unfortunately.  There is Linux-specific
 137 code to access data in user space in some other source files at the
 138 moment.  --philb]
 139
 140 float_exception_flags is a global variable in SoftFloat.
 141
 142 This function is called by the SoftFloat routines to raise a floating
 143 point exception.  We check the trap enable byte in the FPSR, and raise
 144 a SIGFPE exception if necessary.  If not the relevant bits in the
 145 cumulative exceptions flag byte are set and we return.
 146 */
 147
 148 void float_raise(signed char flags)
 149 {
 150 #if 0
 151   printk(KERN_DEBUG "NWFPE: exception %08x at %08x from %08x\n", flags,
 152          __builtin_return_address(0), userRegisters[15]);
 153 #endif
 154
 155   float_exception_flags |= flags;
 156   if (readFPSR() & (flags << 16))
 157   {
 158     /* raise exception */
 159     C_SYMBOL_NAME(fp_send_sig)(SIGFPE,C_SYMBOL_NAME(current),1);
 160   }
 161   else
 162   {
 163     /* set the cumulative exceptions flags */
 164     writeFPSR(flags);
 165   }
 166 }