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traps.c

/* MN10300 Exception handling
 *
 * Copyright (C) 2007 Matsushita Electric Industrial Co., Ltd.
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Modified by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/kallsyms.h>
#include <linux/pci.h>
#include <linux/kdebug.h>
#include <linux/bug.h>
#include <linux/irq.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 <asm/pgalloc.h>
#include <asm/cacheflush.h>
#include <asm/cpu-regs.h>
#include <asm/busctl-regs.h>
#include <asm/unit/leds.h>
#include <asm/fpu.h>
#include <asm/gdb-stub.h>
#include <asm/sections.h>

#if (CONFIG_INTERRUPT_VECTOR_BASE & 0xffffff)
#error "INTERRUPT_VECTOR_BASE not aligned to 16MiB boundary!"
#endif

struct pt_regs *__frame; /* current frame pointer */
EXPORT_SYMBOL(__frame);

int kstack_depth_to_print = 24;

spinlock_t die_lock = __SPIN_LOCK_UNLOCKED(die_lock);

ATOMIC_NOTIFIER_HEAD(mn10300_die_chain);

/*
 * These constants are for searching for possible module text
 * segments. MODULE_RANGE is a guess of how much space is likely
 * to be vmalloced.
 */
#define MODULE_RANGE (8 * 1024 * 1024)

#define DO_ERROR(signr, prologue, str, name)                \
asmlinkage void name(struct pt_regs *regs, u32 intcode)           \
{                                               \
      prologue;                                 \
      if (die_if_no_fixup(str, regs, intcode))        \
            return;                                   \
      force_sig(signr, current);                      \
}

#define DO_EINFO(signr, prologue, str, name, sicode)              \
asmlinkage void name(struct pt_regs *regs, u32 intcode)                 \
{                                                     \
      siginfo_t info;                                       \
      prologue;                                       \
      if (die_if_no_fixup(str, regs, intcode))              \
            return;                                         \
      info.si_signo = signr;                                \
      if (signr == SIGILL && sicode == ILL_ILLOPC) {              \
            uint8_t opcode;                                 \
            if (get_user(opcode, (uint8_t __user *)regs->pc) == 0)      \
                  if (opcode == 0xff)                       \
                        info.si_signo = SIGTRAP;            \
      }                                               \
      info.si_errno = 0;                                    \
      info.si_code = sicode;                                \
      info.si_addr = (void *) regs->pc;                     \
      force_sig_info(info.si_signo, &info, current);              \
}

DO_ERROR(SIGTRAP, {}, "trap",             trap);
DO_ERROR(SIGSEGV, {}, "ibreak",                 ibreak);
DO_ERROR(SIGSEGV, {}, "obreak",                 obreak);
DO_EINFO(SIGSEGV, {}, "access error",           access_error,     SEGV_ACCERR);
DO_EINFO(SIGSEGV, {}, "insn access error",      insn_acc_error,   SEGV_ACCERR);
DO_EINFO(SIGSEGV, {}, "data access error",      data_acc_error,   SEGV_ACCERR);
DO_EINFO(SIGILL,  {}, "privileged opcode",      priv_op,    ILL_PRVOPC);
DO_EINFO(SIGILL,  {}, "invalid opcode",         invalid_op, ILL_ILLOPC);
DO_EINFO(SIGILL,  {}, "invalid ex opcode",      invalid_exop,     ILL_ILLOPC);
DO_EINFO(SIGBUS,  {}, "invalid address",  mem_error,  BUS_ADRERR);
DO_EINFO(SIGBUS,  {}, "bus error",        bus_error,  BUS_ADRERR);
DO_EINFO(SIGILL,  {}, "FPU invalid opcode",     fpu_invalid_op,   ILL_COPROC);

DO_ERROR(SIGTRAP,
#ifndef CONFIG_MN10300_USING_JTAG
       DCR &= ~0x0001,
#else
       {},
#endif
       "single step", istep);

/*
 * handle NMI
 */
asmlinkage void nmi(struct pt_regs *regs, enum exception_code code)
{
      /* see if gdbstub wants to deal with it */
#ifdef CONFIG_GDBSTUB
      if (gdbstub_intercept(regs, code))
            return;
#endif

      printk(KERN_WARNING "--- Register Dump ---\n");
      show_registers(regs);
      printk(KERN_WARNING "---------------------\n");
}

/*
 * show a stack trace from the specified stack pointer
 */
void show_trace(unsigned long *sp)
{
      unsigned long *stack, addr, module_start, module_end;
      int i;

      printk(KERN_EMERG "\n"
             KERN_EMERG "Call Trace:");

      stack = sp;
      i = 0;
      module_start = VMALLOC_START;
      module_end = VMALLOC_END;

      while (((long) stack & (THREAD_SIZE - 1)) != 0) {
            addr = *stack++;
            if (__kernel_text_address(addr)) {
#if 1
                  printk(" [<%08lx>]", addr);
                  print_symbol(" %s", addr);
                  printk("\n");
#else
                  if ((i % 6) == 0)
                        printk("\n" KERN_EMERG "  ");
                  printk("[<%08lx>] ", addr);
                  i++;
#endif
            }
      }

      printk("\n");
}

/*
 * show the raw stack from the specified stack pointer
 */
void show_stack(struct task_struct *task, unsigned long *sp)
{
      unsigned long *stack;
      int i;

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

      stack = sp;
      printk(KERN_EMERG "Stack:");
      for (i = 0; i < kstack_depth_to_print; i++) {
            if (((long) stack & (THREAD_SIZE - 1)) == 0)
                  break;
            if ((i % 8) == 0)
                  printk("\n" KERN_EMERG "  ");
            printk("%08lx ", *stack++);
      }

      show_trace(sp);
}

/*
 * the architecture-independent dump_stack generator
 */
void dump_stack(void)
{
      unsigned long stack;

      show_stack(current, &stack);
}
EXPORT_SYMBOL(dump_stack);

/*
 * dump the register file in the specified exception frame
 */
void show_registers_only(struct pt_regs *regs)
{
      unsigned long ssp;

      ssp = (unsigned long) regs + sizeof(*regs);

      printk(KERN_EMERG "PC:  %08lx EPSW:  %08lx  SSP: %08lx mode: %s\n",
             regs->pc, regs->epsw, ssp, user_mode(regs) ? "User" : "Super");
      printk(KERN_EMERG "d0:  %08lx   d1:  %08lx   d2: %08lx   d3: %08lx\n",
             regs->d0, regs->d1, regs->d2, regs->d3);
      printk(KERN_EMERG "a0:  %08lx   a1:  %08lx   a2: %08lx   a3: %08lx\n",
             regs->a0, regs->a1, regs->a2, regs->a3);
      printk(KERN_EMERG "e0:  %08lx   e1:  %08lx   e2: %08lx   e3: %08lx\n",
             regs->e0, regs->e1, regs->e2, regs->e3);
      printk(KERN_EMERG "e4:  %08lx   e5:  %08lx   e6: %08lx   e7: %08lx\n",
             regs->e4, regs->e5, regs->e6, regs->e7);
      printk(KERN_EMERG "lar: %08lx   lir: %08lx  mdr: %08lx  usp: %08lx\n",
             regs->lar, regs->lir, regs->mdr, regs->sp);
      printk(KERN_EMERG "cvf: %08lx   crl: %08lx  crh: %08lx  drq: %08lx\n",
             regs->mcvf, regs->mcrl, regs->mcrh, regs->mdrq);
      printk(KERN_EMERG "threadinfo=%p task=%p)\n",
             current_thread_info(), current);

      if ((unsigned long) current >= 0x90000000UL &&
          (unsigned long) current < 0x94000000UL)
            printk(KERN_EMERG "Process %s (pid: %d)\n",
                   current->comm, current->pid);

      printk(KERN_EMERG "CPUP:   %04hx\n", CPUP);
      printk(KERN_EMERG "TBR:    %08x\n", TBR);
      printk(KERN_EMERG "DEAR:   %08x\n", DEAR);
      printk(KERN_EMERG "sISR:   %08x\n", sISR);
      printk(KERN_EMERG "NMICR:  %04hx\n", NMICR);
      printk(KERN_EMERG "BCBERR: %08x\n", BCBERR);
      printk(KERN_EMERG "BCBEAR: %08x\n", BCBEAR);
      printk(KERN_EMERG "MMUFCR: %08x\n", MMUFCR);
      printk(KERN_EMERG "IPTEU : %08x  IPTEL2: %08x\n", IPTEU, IPTEL2);
      printk(KERN_EMERG "DPTEU:  %08x  DPTEL2: %08x\n", DPTEU, DPTEL2);
}

/*
 * dump the registers and the stack
 */
void show_registers(struct pt_regs *regs)
{
      unsigned long sp;
      int i;

      show_registers_only(regs);

      if (!user_mode(regs))
            sp = (unsigned long) regs + sizeof(*regs);
      else
            sp = regs->sp;

      /* when in-kernel, we also print out the stack and code at the
       * time of the fault..
       */
      if (!user_mode(regs)) {
            printk(KERN_EMERG "\n");
            show_stack(current, (unsigned long *) sp);

#if 0
            printk(KERN_EMERG "\n"
                   KERN_EMERG "Code: ");
            if (regs->pc < PAGE_OFFSET)
                  goto bad;

            for (i = 0; i < 20; i++) {
                  unsigned char c;
                  if (__get_user(c, &((unsigned char *) regs->pc)[i]))
                        goto bad;
                  printk("%02x ", c);
            }
#else
            i = 0;
#endif
      }

      printk("\n");
      return;

#if 0
bad:
      printk(KERN_EMERG " Bad PC value.");
      break;
#endif
}

/*
 *
 */
void show_trace_task(struct task_struct *tsk)
{
      unsigned long sp = tsk->thread.sp;

      /* User space on another CPU? */
      if ((sp ^ (unsigned long) tsk) & (PAGE_MASK << 1))
            return;

      show_trace((unsigned long *) sp);
}

/*
 * note the untimely death of part of the kernel
 */
void die(const char *str, struct pt_regs *regs, enum exception_code code)
{
      console_verbose();
      spin_lock_irq(&die_lock);
      printk(KERN_EMERG "\n"
             KERN_EMERG "%s: %04x\n",
             str, code & 0xffff);
      show_registers(regs);

      if (regs->pc >= 0x02000000 && regs->pc < 0x04000000 &&
          (regs->epsw & (EPSW_IM | EPSW_IE)) != (EPSW_IM | EPSW_IE)) {
            printk(KERN_EMERG "Exception in usermode interrupt handler\n");
            printk(KERN_EMERG "\n"
                   KERN_EMERG "  Please connect to kernel debugger !!\n");
            asm volatile ("0: bra 0b");
      }

      spin_unlock_irq(&die_lock);
      do_exit(SIGSEGV);
}

/*
 * see if there's a fixup handler we can force a jump to when an exception
 * happens due to something kernel code did
 */
int die_if_no_fixup(const char *str, struct pt_regs *regs,
                enum exception_code code)
{
      if (user_mode(regs))
            return 0;

      peripheral_leds_display_exception(code);

      switch (code) {
            /* see if we can fixup the kernel accessing memory */
      case EXCEP_ITLBMISS:
      case EXCEP_DTLBMISS:
      case EXCEP_IAERROR:
      case EXCEP_DAERROR:
      case EXCEP_MEMERR:
      case EXCEP_MISALIGN:
      case EXCEP_BUSERROR:
      case EXCEP_ILLDATACC:
      case EXCEP_IOINSACC:
      case EXCEP_PRIVINSACC:
      case EXCEP_PRIVDATACC:
      case EXCEP_DATINSACC:
            if (fixup_exception(regs))
                  return 1;
      case EXCEP_UNIMPINS:
            if (regs->pc && *(uint8_t *)regs->pc == 0xff)
                  if (notify_die(DIE_BREAKPOINT, str, regs, code, 0, 0))
                        return 1;
            break;
      default:
            break;
      }

      /* see if gdbstub wants to deal with it */
#ifdef CONFIG_GDBSTUB
      if (gdbstub_intercept(regs, code))
            return 1;
#endif

      if (notify_die(DIE_GPF, str, regs, code, 0, 0))
            return 1;

      /* make the process die as the last resort */
      die(str, regs, code);
}

/*
 * handle unsupported syscall instructions (syscall 1-15)
 */
static asmlinkage void unsupported_syscall(struct pt_regs *regs,
                                 enum exception_code code)
{
      struct task_struct *tsk = current;
      siginfo_t info;

      /* catch a kernel BUG() */
      if (code == EXCEP_SYSCALL15 && !user_mode(regs)) {
            if (report_bug(regs->pc, regs) == BUG_TRAP_TYPE_BUG) {
#ifdef CONFIG_GDBSTUB
                  gdbstub_intercept(regs, code);
#endif
            }
      }

      regs->pc -= 2; /* syscall return addr is _after_ the instruction */

      die_if_no_fixup("An unsupported syscall insn was used by the kernel\n",
                  regs, code);

      info.si_signo     = SIGILL;
      info.si_errno     = ENOSYS;
      info.si_code      = ILL_ILLTRP;
      info.si_addr      = (void *) regs->pc;
      force_sig_info(SIGILL, &info, tsk);
}

/*
 * display the register file when the stack pointer gets clobbered
 */
asmlinkage void do_double_fault(struct pt_regs *regs)
{
      struct task_struct *tsk = current;

      strcpy(tsk->comm, "emergency tsk");
      tsk->pid = 0;
      console_verbose();
      printk(KERN_EMERG "--- double fault ---\n");
      show_registers(regs);
}

/*
 * asynchronous bus error (external, usually I/O DMA)
 */
asmlinkage void io_bus_error(u32 bcberr, u32 bcbear, struct pt_regs *regs)
{
      console_verbose();

      printk(KERN_EMERG "\n"
             KERN_EMERG "Asynchronous I/O Bus Error\n"
             KERN_EMERG "==========================\n");

      if (bcberr & BCBERR_BEME)
            printk(KERN_EMERG "- Multiple recorded errors\n");

      printk(KERN_EMERG "- Faulting Buses:%s%s%s\n",
             bcberr & BCBERR_BEMR_CI  ? " CPU-Ins-Fetch" : "",
             bcberr & BCBERR_BEMR_CD  ? " CPU-Data" : "",
             bcberr & BCBERR_BEMR_DMA ? " DMA" : "");

      printk(KERN_EMERG "- %s %s access made to %s at address %08x\n",
             bcberr &   BCBERR_BEBST ? "Burst" : "Single",
             bcberr &   BCBERR_BERW ? "Read" : "Write",
             bcberr &   BCBERR_BESB_MON  ? "Monitor Space" :
             bcberr &   BCBERR_BESB_IO   ? "Internal CPU I/O Space" :
             bcberr &   BCBERR_BESB_EX   ? "External I/O Bus" :
             bcberr &   BCBERR_BESB_OPEX ? "External Memory Bus" :
             "On Chip Memory",
             bcbear
             );

      printk(KERN_EMERG "- Detected by the %s\n",
             bcberr&BCBERR_BESD ? "Bus Control Unit" : "Slave Bus");

#ifdef CONFIG_PCI
#define BRIDGEREGB(X) (*(volatile __u8  *)(0xBE040000 + (X)))
#define BRIDGEREGW(X) (*(volatile __u16 *)(0xBE040000 + (X)))
#define BRIDGEREGL(X) (*(volatile __u32 *)(0xBE040000 + (X)))

      printk(KERN_EMERG "- PCI Memory Paging Reg:         %08x\n",
             *(volatile __u32 *) (0xBFFFFFF4));
      printk(KERN_EMERG "- PCI Bridge Base Address 0:     %08x\n",
             BRIDGEREGL(PCI_BASE_ADDRESS_0));
      printk(KERN_EMERG "- PCI Bridge AMPCI Base Address: %08x\n",
             BRIDGEREGL(0x48));
      printk(KERN_EMERG "- PCI Bridge Command:                %04hx\n",
             BRIDGEREGW(PCI_COMMAND));
      printk(KERN_EMERG "- PCI Bridge Status:                 %04hx\n",
             BRIDGEREGW(PCI_STATUS));
      printk(KERN_EMERG "- PCI Bridge Int Status:         %08hx\n",
             BRIDGEREGL(0x4c));
#endif

      printk(KERN_EMERG "\n");
      show_registers(regs);

      panic("Halted due to asynchronous I/O Bus Error\n");
}

/*
 * handle an exception for which a handler has not yet been installed
 */
asmlinkage void uninitialised_exception(struct pt_regs *regs,
                              enum exception_code code)
{

      /* see if gdbstub wants to deal with it */
#ifdef CONFIG_GDBSTUB
      if (gdbstub_intercept(regs, code))
            return;
#endif

      peripheral_leds_display_exception(code);
      printk(KERN_EMERG "Uninitialised Exception 0x%04x\n", code & 0xFFFF);
      show_registers(regs);

      for (;;)
            continue;
}

/*
 * set an interrupt stub to jump to a handler
 * ! NOTE: this does *not* flush the caches
 */
void __init __set_intr_stub(enum exception_code code, void *handler)
{
      unsigned long addr;
      u8 *vector = (u8 *)(CONFIG_INTERRUPT_VECTOR_BASE + code);

      addr = (unsigned long) handler - (unsigned long) vector;
      vector[0] = 0xdc;       /* JMP handler */
      vector[1] = addr;
      vector[2] = addr >> 8;
      vector[3] = addr >> 16;
      vector[4] = addr >> 24;
      vector[5] = 0xcb;
      vector[6] = 0xcb;
      vector[7] = 0xcb;
}

/*
 * set an interrupt stub to jump to a handler
 */
void __init set_intr_stub(enum exception_code code, void *handler)
{
      unsigned long addr;
      u8 *vector = (u8 *)(CONFIG_INTERRUPT_VECTOR_BASE + code);

      addr = (unsigned long) handler - (unsigned long) vector;
      vector[0] = 0xdc;       /* JMP handler */
      vector[1] = addr;
      vector[2] = addr >> 8;
      vector[3] = addr >> 16;
      vector[4] = addr >> 24;
      vector[5] = 0xcb;
      vector[6] = 0xcb;
      vector[7] = 0xcb;

      mn10300_dcache_flush_inv();
      mn10300_icache_inv();
}

/*
 * set an interrupt stub to invoke the JTAG unit and then jump to a handler
 */
void __init set_jtag_stub(enum exception_code code, void *handler)
{
      unsigned long addr;
      u8 *vector = (u8 *)(CONFIG_INTERRUPT_VECTOR_BASE + code);

      addr = (unsigned long) handler - ((unsigned long) vector + 1);
      vector[0] = 0xff;       /* PI to jump into JTAG debugger */
      vector[1] = 0xdc;       /* jmp handler */
      vector[2] = addr;
      vector[3] = addr >> 8;
      vector[4] = addr >> 16;
      vector[5] = addr >> 24;
      vector[6] = 0xcb;
      vector[7] = 0xcb;

      mn10300_dcache_flush_inv();
      flush_icache_range((unsigned long) vector, (unsigned long) vector + 8);
}

/*
 * initialise the exception table
 */
void __init trap_init(void)
{
      set_excp_vector(EXCEP_TRAP,         trap);
      set_excp_vector(EXCEP_ISTEP,        istep);
      set_excp_vector(EXCEP_IBREAK,       ibreak);
      set_excp_vector(EXCEP_OBREAK,       obreak);

      set_excp_vector(EXCEP_PRIVINS,            priv_op);
      set_excp_vector(EXCEP_UNIMPINS,           invalid_op);
      set_excp_vector(EXCEP_UNIMPEXINS,   invalid_exop);
      set_excp_vector(EXCEP_MEMERR,       mem_error);
      set_excp_vector(EXCEP_MISALIGN,           misalignment);
      set_excp_vector(EXCEP_BUSERROR,           bus_error);
      set_excp_vector(EXCEP_ILLINSACC,    insn_acc_error);
      set_excp_vector(EXCEP_ILLDATACC,    data_acc_error);
      set_excp_vector(EXCEP_IOINSACC,           insn_acc_error);
      set_excp_vector(EXCEP_PRIVINSACC,   insn_acc_error);
      set_excp_vector(EXCEP_PRIVDATACC,   data_acc_error);
      set_excp_vector(EXCEP_DATINSACC,    insn_acc_error);
      set_excp_vector(EXCEP_FPU_DISABLED, fpu_disabled);
      set_excp_vector(EXCEP_FPU_UNIMPINS, fpu_invalid_op);
      set_excp_vector(EXCEP_FPU_OPERATION,      fpu_exception);

      set_excp_vector(EXCEP_NMI,          nmi);

      set_excp_vector(EXCEP_SYSCALL1,           unsupported_syscall);
      set_excp_vector(EXCEP_SYSCALL2,           unsupported_syscall);
      set_excp_vector(EXCEP_SYSCALL3,           unsupported_syscall);
      set_excp_vector(EXCEP_SYSCALL4,           unsupported_syscall);
      set_excp_vector(EXCEP_SYSCALL5,           unsupported_syscall);
      set_excp_vector(EXCEP_SYSCALL6,           unsupported_syscall);
      set_excp_vector(EXCEP_SYSCALL7,           unsupported_syscall);
      set_excp_vector(EXCEP_SYSCALL8,           unsupported_syscall);
      set_excp_vector(EXCEP_SYSCALL9,           unsupported_syscall);
      set_excp_vector(EXCEP_SYSCALL10,    unsupported_syscall);
      set_excp_vector(EXCEP_SYSCALL11,    unsupported_syscall);
      set_excp_vector(EXCEP_SYSCALL12,    unsupported_syscall);
      set_excp_vector(EXCEP_SYSCALL13,    unsupported_syscall);
      set_excp_vector(EXCEP_SYSCALL14,    unsupported_syscall);
      set_excp_vector(EXCEP_SYSCALL15,    unsupported_syscall);
}

/*
 * determine if a program counter value is a valid bug address
 */
int is_valid_bugaddr(unsigned long pc)
{
      return pc >= PAGE_OFFSET;
}

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