arch/sh/kernel/traps.c

   1 /*
   2  *  linux/arch/sh/traps.c
   3  *
   4  *  SuperH version: Copyright (C) 1999  Niibe Yutaka
   5  */
   6
   7 /*
   8  * 'Traps.c' handles hardware traps and faults after we have saved some
   9  * state in 'entry.S'.
  10  */
  11 #include <linux/sched.h>
  12 #include <linux/kernel.h>
  13 #include <linux/string.h>
  14 #include <linux/errno.h>
  15 #include <linux/ptrace.h>
  16 #include <linux/timer.h>
  17 #include <linux/mm.h>
  18 #include <linux/smp.h>
  19 #include <linux/smp_lock.h>
  20 #include <linux/init.h>
  21 #include <linux/delay.h>
  22 #include <linux/spinlock.h>
  23
  24 #include <asm/system.h>
  25 #include <asm/uaccess.h>
  26 #include <asm/io.h>
  27 #include <asm/atomic.h>
  28
  29 static inline void console_verbose(void)
  30 {
  31         extern int console_loglevel;
  32         console_loglevel = 15;
  33 }
  34
  35 #define DO_ERROR(trapnr, signr, str, name, tsk) \
  36 asmlinkage void do_##name(unsigned long r4, unsigned long r5, \
  37                           unsigned long r6, unsigned long r7, \
  38                           struct pt_regs regs) \
  39 { \
  40         unsigned long error_code; \
  41  \
  42         asm volatile("stc       r2_bank,%0": "=r" (error_code)); \
  43         sti(); \
  44         regs.syscall_nr = -1; \
  45         tsk->thread.error_code = error_code; \
  46         tsk->thread.trap_no = trapnr; \
  47         force_sig(signr, tsk); \
  48         die_if_no_fixup(str,&regs,error_code); \
  49 }
  50
  51 /*
  52  * These constants are for searching for possible module text
  53  * segments.  VMALLOC_OFFSET comes from mm/vmalloc.c; MODULE_RANGE is
  54  * a guess of how much space is likely to be vmalloced.
  55  */
  56 #define VMALLOC_OFFSET (8*1024*1024)
  57 #define MODULE_RANGE (8*1024*1024)
  58
  59 static void show_registers(struct pt_regs *regs)
  60 {/* Not implemented yet. */
  61 }
  62
  63 spinlock_t die_lock;
  64
  65 void die(const char * str, struct pt_regs * regs, long err)
  66 {
  67         console_verbose();
  68         spin_lock_irq(&die_lock);
  69         printk("%s: %04lx\n", str, err & 0xffff);
  70         show_registers(regs);
  71         spin_unlock_irq(&die_lock);
  72         do_exit(SIGSEGV);
  73 }
  74
  75 static inline void die_if_kernel(const char * str, struct pt_regs * regs, long err)
  76 {
  77         if (!user_mode(regs))
  78                 die(str, regs, err);
  79 }
  80
  81 static void die_if_no_fixup(const char * str, struct pt_regs * regs, long err)
  82 {
  83         if (!user_mode(regs))
  84         {
  85                 unsigned long fixup;
  86                 fixup = search_exception_table(regs->pc);
  87                 if (fixup) {
  88                         regs->pc = fixup;
  89                         return;
  90                 }
  91                 die(str, regs, err);
  92         }
  93 }
  94
  95 DO_ERROR( 7, SIGSEGV, "address error (load)", address_error_load, current)
  96 DO_ERROR( 8, SIGSEGV, "address error (store)", address_error_store, current)
  97 DO_ERROR(12, SIGILL,  "reserved instruction", reserved_inst, current)
  98 DO_ERROR(13, SIGILL,  "illegal slot instruction", illegal_slot_inst, current)
  99
 100 asmlinkage void do_exception_error (unsigned long r4, unsigned long r5,
 101                                     unsigned long r6, unsigned long r7,
 102                                     struct pt_regs regs)
 103 {
 104         long ex;
 105         asm volatile("stc       r2_bank,%0" : "=r" (ex));
 106         die_if_kernel("exception", &regs, ex);
 107 }
 108
 109 void __init trap_init(void)
 110 {
 111         extern void *vbr_base;
 112         extern void *exception_handling_table[14];
 113
 114         exception_handling_table[7] = (void *)do_address_error_load;
 115         exception_handling_table[8] = (void *)do_address_error_store;
 116         exception_handling_table[12] = (void *)do_reserved_inst;
 117         exception_handling_table[13] = (void *)do_illegal_slot_inst;
 118
 119         /* NOTE: The VBR value should be at P1
 120            (or P2, virtural "fixed" address space).
 121            It's definitely should not in physical address.  */
 122
 123         asm volatile("ldc       %0,vbr"
 124                      : /* no output */
 125                      : "r" (&vbr_base)
 126                      : "memory");
 127 }