arch/microblaze/kernel/exceptions.c

   1 /*
   2  * HW exception handling
   3  *
   4  * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
   5  * Copyright (C) 2008 PetaLogix
   6  *
   7  * This file is subject to the terms and conditions of the GNU General
   8  * Public License.  See the file COPYING in the main directory of this
   9  * archive for more details.
  10  */
  11
  12 /*
  13  * This file handles the architecture-dependent parts of hardware exceptions
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/signal.h>
  18 #include <linux/sched.h>
  19 #include <linux/kallsyms.h>
  20 #include <linux/module.h>
  21
  22 #include <asm/exceptions.h>
  23 #include <asm/entry.h>          /* For KM CPU var */
  24 #include <linux/uaccess.h>
  25 #include <linux/errno.h>
  26 #include <linux/ptrace.h>
  27 #include <asm/current.h>
  28
  29 #define MICROBLAZE_ILL_OPCODE_EXCEPTION 0x02
  30 #define MICROBLAZE_IBUS_EXCEPTION       0x03
  31 #define MICROBLAZE_DBUS_EXCEPTION       0x04
  32 #define MICROBLAZE_DIV_ZERO_EXCEPTION   0x05
  33 #define MICROBLAZE_FPU_EXCEPTION        0x06
  34 #define MICROBLAZE_PRIVILEGED_EXCEPTION 0x07
  35
  36 static DEFINE_SPINLOCK(die_lock);
  37
  38 void die(const char *str, struct pt_regs *fp, long err)
  39 {
  40         console_verbose();
  41         spin_lock_irq(&die_lock);
  42         printk(KERN_WARNING "Oops: %s, sig: %ld\n", str, err);
  43         show_regs(fp);
  44         spin_unlock_irq(&die_lock);
  45         /* do_exit() should take care of panic'ing from an interrupt
  46          * context so we don't handle it here
  47          */
  48         do_exit(err);
  49 }
  50
  51 void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
  52 {
  53         siginfo_t info;
  54
  55         if (kernel_mode(regs)) {
  56                 debugger(regs);
  57                 die("Exception in kernel mode", regs, signr);
  58         }
  59         info.si_signo = signr;
  60         info.si_errno = 0;
  61         info.si_code = code;
  62         info.si_addr = (void __user *) addr;
  63         force_sig_info(signr, &info, current);
  64 }
  65
  66 asmlinkage void full_exception(struct pt_regs *regs, unsigned int type,
  67                                                         int fsr, int addr)
  68 {
  69 #ifdef CONFIG_MMU
  70         int code;
  71         addr = regs->pc;
  72 #endif
  73
  74 #if 0
  75         printk(KERN_WARNING "Exception %02x in %s mode, FSR=%08x PC=%08x " \
  76                                                         "ESR=%08x\n",
  77                         type, user_mode(regs) ? "user" : "kernel", fsr,
  78                         (unsigned int) regs->pc, (unsigned int) regs->esr);
  79 #endif
  80
  81         switch (type & 0x1F) {
  82         case MICROBLAZE_ILL_OPCODE_EXCEPTION:
  83                 if (user_mode(regs)) {
  84                         pr_debug(KERN_WARNING "Illegal opcode exception " \
  85                                                         "in user mode.\n");
  86                         _exception(SIGILL, regs, ILL_ILLOPC, addr);
  87                         return;
  88                 }
  89                 printk(KERN_WARNING "Illegal opcode exception " \
  90                                                         "in kernel mode.\n");
  91                 die("opcode exception", regs, SIGBUS);
  92                 break;
  93         case MICROBLAZE_IBUS_EXCEPTION:
  94                 if (user_mode(regs)) {
  95                         pr_debug(KERN_WARNING "Instruction bus error " \
  96                                                 "exception in user mode.\n");
  97                         _exception(SIGBUS, regs, BUS_ADRERR, addr);
  98                         return;
  99                 }
 100                 printk(KERN_WARNING "Instruction bus error exception " \
 101                                                         "in kernel mode.\n");
 102                 die("bus exception", regs, SIGBUS);
 103                 break;
 104         case MICROBLAZE_DBUS_EXCEPTION:
 105                 if (user_mode(regs)) {
 106                         pr_debug(KERN_WARNING "Data bus error exception " \
 107                                                         "in user mode.\n");
 108                         _exception(SIGBUS, regs, BUS_ADRERR, addr);
 109                         return;
 110                 }
 111                 printk(KERN_WARNING "Data bus error exception " \
 112                                                         "in kernel mode.\n");
 113                 die("bus exception", regs, SIGBUS);
 114                 break;
 115         case MICROBLAZE_DIV_ZERO_EXCEPTION:
 116                 if (user_mode(regs)) {
 117                         pr_debug(KERN_WARNING "Divide by zero exception " \
 118                                                         "in user mode\n");
 119                         _exception(SIGILL, regs, FPE_INTDIV, addr);
 120                         return;
 121                 }
 122                 printk(KERN_WARNING "Divide by zero exception " \
 123                                                         "in kernel mode.\n");
 124                 die("Divide by zero exception", regs, SIGBUS);
 125                 break;
 126         case MICROBLAZE_FPU_EXCEPTION:
 127                 pr_debug(KERN_WARNING "FPU exception\n");
 128                 /* IEEE FP exception */
 129                 /* I removed fsr variable and use code var for storing fsr */
 130                 if (fsr & FSR_IO)
 131                         fsr = FPE_FLTINV;
 132                 else if (fsr & FSR_OF)
 133                         fsr = FPE_FLTOVF;
 134                 else if (fsr & FSR_UF)
 135                         fsr = FPE_FLTUND;
 136                 else if (fsr & FSR_DZ)
 137                         fsr = FPE_FLTDIV;
 138                 else if (fsr & FSR_DO)
 139                         fsr = FPE_FLTRES;
 140                 _exception(SIGFPE, regs, fsr, addr);
 141                 break;
 142
 143 #ifdef CONFIG_MMU
 144         case MICROBLAZE_PRIVILEGED_EXCEPTION:
 145                 pr_debug(KERN_WARNING "Privileged exception\n");
 146                 /* "brk r0,r0" - used as debug breakpoint */
 147                 if (get_user(code, (unsigned long *)regs->pc) == 0
 148                         && code == 0x980c0000) {
 149                         _exception(SIGTRAP, regs, TRAP_BRKPT, addr);
 150                 } else {
 151                         _exception(SIGILL, regs, ILL_PRVOPC, addr);
 152                 }
 153                 break;
 154 #endif
 155         default:
 156         /* FIXME what to do in unexpected exception */
 157                 printk(KERN_WARNING "Unexpected exception %02x "
 158                         "PC=%08x in %s mode\n", type, (unsigned int) addr,
 159                         kernel_mode(regs) ? "kernel" : "user");
 160         }
 161         return;
 162 }