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traps.c

/*
 *  linux/arch/m32r/kernel/traps.c
 *
 *  Copyright (C) 2001, 2002  Hirokazu Takata, Hiroyuki Kondo,
 *                            Hitoshi Yamamoto
 */

/*
 * 'traps.c' handles hardware traps and faults after we have saved some
 * state in 'entry.S'.
 */
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/kallsyms.h>
#include <linux/stddef.h>
#include <linux/ptrace.h>
#include <linux/mm.h>
#include <asm/page.h>
#include <asm/processor.h>

#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/atomic.h>

#include <asm/smp.h>

#include <linux/module.h>

asmlinkage void alignment_check(void);
asmlinkage void ei_handler(void);
asmlinkage void rie_handler(void);
asmlinkage void debug_trap(void);
asmlinkage void cache_flushing_handler(void);
asmlinkage void ill_trap(void);

#ifdef CONFIG_SMP
extern void smp_reschedule_interrupt(void);
extern void smp_invalidate_interrupt(void);
extern void smp_call_function_interrupt(void);
extern void smp_ipi_timer_interrupt(void);
extern void smp_flush_cache_all_interrupt(void);

/*
 * for Boot AP function
 */
asm (
      "     .section .eit_vector4,\"ax\"  \n"
      "     .global _AP_RE                \n"
      "     .global startup_AP            \n"
      "_AP_RE:                      \n"
      "     .fill 32, 4, 0                \n"
      "_AP_EI: bra      startup_AP        \n"
      "     .previous               \n"
);
#endif  /* CONFIG_SMP */

extern unsigned long    eit_vector[];
#define BRA_INSN(func, entry) \
      ((unsigned long)func - (unsigned long)eit_vector - entry*4)/4 \
      + 0xff000000UL

void  set_eit_vector_entries(void)
{
      extern void default_eit_handler(void);
      extern void system_call(void);
      extern void pie_handler(void);
      extern void ace_handler(void);
      extern void tme_handler(void);
      extern void _flush_cache_copyback_all(void);

      eit_vector[0] = 0xd0c00001; /* seth r0, 0x01 */
      eit_vector[1] = BRA_INSN(default_eit_handler, 1);
      eit_vector[4] = 0xd0c00010; /* seth r0, 0x10 */
      eit_vector[5] = BRA_INSN(default_eit_handler, 5);
      eit_vector[8] = BRA_INSN(rie_handler, 8);
      eit_vector[12] = BRA_INSN(alignment_check, 12);
      eit_vector[16] = BRA_INSN(ill_trap, 16);
      eit_vector[17] = BRA_INSN(debug_trap, 17);
      eit_vector[18] = BRA_INSN(system_call, 18);
      eit_vector[19] = BRA_INSN(ill_trap, 19);
      eit_vector[20] = BRA_INSN(ill_trap, 20);
      eit_vector[21] = BRA_INSN(ill_trap, 21);
      eit_vector[22] = BRA_INSN(ill_trap, 22);
      eit_vector[23] = BRA_INSN(ill_trap, 23);
      eit_vector[24] = BRA_INSN(ill_trap, 24);
      eit_vector[25] = BRA_INSN(ill_trap, 25);
      eit_vector[26] = BRA_INSN(ill_trap, 26);
      eit_vector[27] = BRA_INSN(ill_trap, 27);
      eit_vector[28] = BRA_INSN(cache_flushing_handler, 28);
      eit_vector[29] = BRA_INSN(ill_trap, 29);
      eit_vector[30] = BRA_INSN(ill_trap, 30);
      eit_vector[31] = BRA_INSN(ill_trap, 31);
      eit_vector[32] = BRA_INSN(ei_handler, 32);
      eit_vector[64] = BRA_INSN(pie_handler, 64);
#ifdef CONFIG_MMU
      eit_vector[68] = BRA_INSN(ace_handler, 68);
      eit_vector[72] = BRA_INSN(tme_handler, 72);
#endif /* CONFIG_MMU */
#ifdef CONFIG_SMP
      eit_vector[184] = (unsigned long)smp_reschedule_interrupt;
      eit_vector[185] = (unsigned long)smp_invalidate_interrupt;
      eit_vector[186] = (unsigned long)smp_call_function_interrupt;
      eit_vector[187] = (unsigned long)smp_ipi_timer_interrupt;
      eit_vector[188] = (unsigned long)smp_flush_cache_all_interrupt;
      eit_vector[189] = 0;
      eit_vector[190] = 0;
      eit_vector[191] = 0;
#endif
      _flush_cache_copyback_all();
}

void __init trap_init(void)
{
      set_eit_vector_entries();

      /*
       * Should be a barrier for any external CPU state.
       */
      cpu_init();
}

int kstack_depth_to_print = 24;

void show_trace(struct task_struct *task, unsigned long *stack)
{
      unsigned long addr;

      if (!stack)
            stack = (unsigned long*)&stack;

      printk("Call Trace: ");
      while (!kstack_end(stack)) {
            addr = *stack++;
            if (__kernel_text_address(addr)) {
                  printk("[<%08lx>] ", addr);
                  print_symbol("%s\n", addr);
            }
      }
      printk("\n");
}

void show_stack(struct task_struct *task, unsigned long *sp)
{
      unsigned long  *stack;
      int  i;

      /*
       * debugging aid: "show_stack(NULL);" prints the
       * back trace for this cpu.
       */

      if(sp==NULL) {
            if (task)
                  sp = (unsigned long *)task->thread.sp;
            else
                  sp=(unsigned long*)&sp;
      }

      stack = sp;
      for(i=0; i < kstack_depth_to_print; i++) {
            if (kstack_end(stack))
                  break;
            if (i && ((i % 4) == 0))
                  printk("\n       ");
            printk("%08lx ", *stack++);
      }
      printk("\n");
      show_trace(task, sp);
}

void dump_stack(void)
{
      unsigned long stack;

      show_trace(current, &stack);
}

EXPORT_SYMBOL(dump_stack);

static void show_registers(struct pt_regs *regs)
{
      int i = 0;
      int in_kernel = 1;
      unsigned long sp;

      printk("CPU:    %d\n", smp_processor_id());
      show_regs(regs);

      sp = (unsigned long) (1+regs);
      if (user_mode(regs)) {
            in_kernel = 0;
            sp = regs->spu;
            printk("SPU: %08lx\n", sp);
      } else {
            printk("SPI: %08lx\n", sp);
      }
      printk("Process %s (pid: %d, process nr: %d, stackpage=%08lx)",
            current->comm, task_pid_nr(current), 0xffff & i, 4096+(unsigned long)current);

      /*
       * When in-kernel, we also print out the stack and code at the
       * time of the fault..
       */
      if (in_kernel) {
            printk("\nStack: ");
            show_stack(current, (unsigned long*) sp);

            printk("\nCode: ");
            if (regs->bpc < PAGE_OFFSET)
                  goto bad;

            for(i=0;i<20;i++) {
                  unsigned char c;
                  if (__get_user(c, &((unsigned char*)regs->bpc)[i])) {
bad:
                        printk(" Bad PC value.");
                        break;
                  }
                  printk("%02x ", c);
            }
      }
      printk("\n");
}

DEFINE_SPINLOCK(die_lock);

void die(const char * str, struct pt_regs * regs, long err)
{
      console_verbose();
      spin_lock_irq(&die_lock);
      bust_spinlocks(1);
      printk("%s: %04lx\n", str, err & 0xffff);
      show_registers(regs);
      bust_spinlocks(0);
      spin_unlock_irq(&die_lock);
      do_exit(SIGSEGV);
}

static __inline__ void die_if_kernel(const char * str,
      struct pt_regs * regs, long err)
{
      if (!user_mode(regs))
            die(str, regs, err);
}

static __inline__ void do_trap(int trapnr, int signr, const char * str,
      struct pt_regs * regs, long error_code, siginfo_t *info)
{
      if (user_mode(regs)) {
            /* trap_signal */
            struct task_struct *tsk = current;
            tsk->thread.error_code = error_code;
            tsk->thread.trap_no = trapnr;
            if (info)
                  force_sig_info(signr, info, tsk);
            else
                  force_sig(signr, tsk);
            return;
      } else {
            /* kernel_trap */
            if (!fixup_exception(regs))
                  die(str, regs, error_code);
            return;
      }
}

#define DO_ERROR(trapnr, signr, str, name) \
asmlinkage void do_##name(struct pt_regs * regs, long error_code) \
{ \
      do_trap(trapnr, signr, NULL, regs, error_code, NULL); \
}

#define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \
asmlinkage void do_##name(struct pt_regs * regs, long error_code) \
{ \
      siginfo_t info; \
      info.si_signo = signr; \
      info.si_errno = 0; \
      info.si_code = sicode; \
      info.si_addr = (void __user *)siaddr; \
      do_trap(trapnr, signr, str, regs, error_code, &info); \
}

DO_ERROR( 1, SIGTRAP, "debug trap", debug_trap)
DO_ERROR_INFO(0x20, SIGILL,  "reserved instruction ", rie_handler, ILL_ILLOPC, regs->bpc)
DO_ERROR_INFO(0x100, SIGILL,  "privileged instruction", pie_handler, ILL_PRVOPC, regs->bpc)
DO_ERROR_INFO(-1, SIGILL,  "illegal trap", ill_trap, ILL_ILLTRP, regs->bpc)

extern int handle_unaligned_access(unsigned long, struct pt_regs *);

/* This code taken from arch/sh/kernel/traps.c */
asmlinkage void do_alignment_check(struct pt_regs *regs, long error_code)
{
      mm_segment_t oldfs;
      unsigned long insn;
      int tmp;

      oldfs = get_fs();

      if (user_mode(regs)) {
            local_irq_enable();
            current->thread.error_code = error_code;
            current->thread.trap_no = 0x17;

            set_fs(USER_DS);
            if (copy_from_user(&insn, (void *)regs->bpc, 4)) {
                  set_fs(oldfs);
                  goto uspace_segv;
            }
            tmp = handle_unaligned_access(insn, regs);
            set_fs(oldfs);

            if (!tmp)
                  return;

      uspace_segv:
            printk(KERN_NOTICE "Killing process \"%s\" due to unaligned "
                  "access\n", current->comm);
            force_sig(SIGSEGV, current);
      } else {
            set_fs(KERNEL_DS);
            if (copy_from_user(&insn, (void *)regs->bpc, 4)) {
                  set_fs(oldfs);
                  die("insn faulting in do_address_error", regs, 0);
            }
            handle_unaligned_access(insn, regs);
            set_fs(oldfs);
      }
}

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