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* linux/arch/unicore32/kernel/traps.c
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* Code specific to PKUnity SoC and UniCore ISA
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* Copyright (C) 2001-2010 GUAN Xue-tao
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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* 'traps.c' handles hardware exceptions after we have saved some state.
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* Mostly a debugging aid, but will probably kill the offending process.
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#include <linux/module.h>
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#include <linux/signal.h>
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#include <linux/spinlock.h>
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#include <linux/personality.h>
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#include <linux/kallsyms.h>
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#include <linux/kdebug.h>
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#include <linux/uaccess.h>
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#include <linux/delay.h>
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#include <linux/hardirq.h>
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#include <linux/init.h>
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#include <linux/atomic.h>
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#include <linux/unistd.h>
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#include <asm/cacheflush.h>
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#include <asm/system.h>
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#include <asm/traps.h>
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static void dump_mem(const char *, const char *, unsigned long, unsigned long);
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void dump_backtrace_entry(unsigned long where,
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unsigned long from, unsigned long frame)
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#ifdef CONFIG_KALLSYMS
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printk(KERN_DEFAULT "[<%08lx>] (%pS) from [<%08lx>] (%pS)\n",
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where, (void *)where, from, (void *)from);
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printk(KERN_DEFAULT "Function entered at [<%08lx>] from [<%08lx>]\n",
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* Stack pointers should always be within the kernels view of
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* physical memory. If it is not there, then we can't dump
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* out any information relating to the stack.
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static int verify_stack(unsigned long sp)
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if (sp < PAGE_OFFSET ||
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(sp > (unsigned long)high_memory && high_memory != NULL))
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* Dump out the contents of some memory nicely...
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static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
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* We need to switch to kernel mode so that we can use __get_user
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* to safely read from kernel space. Note that we now dump the
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* code first, just in case the backtrace kills us.
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printk(KERN_DEFAULT "%s%s(0x%08lx to 0x%08lx)\n",
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lvl, str, bottom, top);
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for (first = bottom & ~31; first < top; first += 32) {
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char str[sizeof(" 12345678") * 8 + 1];
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memset(str, ' ', sizeof(str));
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str[sizeof(str) - 1] = '\0';
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for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
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if (p >= bottom && p < top) {
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if (__get_user(val, (unsigned long *)p) == 0)
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sprintf(str + i * 9, " %08lx", val);
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sprintf(str + i * 9, " ????????");
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printk(KERN_DEFAULT "%s%04lx:%s\n", lvl, first & 0xffff, str);
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static void dump_instr(const char *lvl, struct pt_regs *regs)
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unsigned long addr = instruction_pointer(regs);
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char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
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* We need to switch to kernel mode so that we can use __get_user
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* to safely read from kernel space. Note that we now dump the
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* code first, just in case the backtrace kills us.
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for (i = -4; i < 1; i++) {
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unsigned int val, bad;
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bad = __get_user(val, &((u32 *)addr)[i]);
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p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ",
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p += sprintf(p, "bad PC value");
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printk(KERN_DEFAULT "%sCode: %s\n", lvl, str);
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static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
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unsigned int fp, mode;
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printk(KERN_DEFAULT "Backtrace: ");
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mode = processor_mode(regs);
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} else if (tsk != current) {
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fp = thread_saved_fp(tsk);
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asm("mov %0, fp" : "=r" (fp) : : "cc");
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printk("no frame pointer");
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} else if (verify_stack(fp)) {
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printk("invalid frame pointer 0x%08x", fp);
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} else if (fp < (unsigned long)end_of_stack(tsk))
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printk("frame pointer underflow");
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c_backtrace(fp, mode);
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void dump_stack(void)
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dump_backtrace(NULL, NULL);
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EXPORT_SYMBOL(dump_stack);
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void show_stack(struct task_struct *tsk, unsigned long *sp)
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dump_backtrace(NULL, tsk);
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static int __die(const char *str, int err, struct thread_info *thread,
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struct pt_regs *regs)
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struct task_struct *tsk = thread->task;
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static int die_counter;
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printk(KERN_EMERG "Internal error: %s: %x [#%d]\n",
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str, err, ++die_counter);
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/* trap and error numbers are mostly meaningless on UniCore */
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ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, \
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if (ret == NOTIFY_STOP)
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printk(KERN_EMERG "Process %.*s (pid: %d, stack limit = 0x%p)\n",
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TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1);
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if (!user_mode(regs) || in_interrupt()) {
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dump_mem(KERN_EMERG, "Stack: ", regs->UCreg_sp,
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THREAD_SIZE + (unsigned long)task_stack_page(tsk));
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dump_backtrace(regs, tsk);
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dump_instr(KERN_EMERG, regs);
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DEFINE_SPINLOCK(die_lock);
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* This function is protected against re-entrancy.
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void die(const char *str, struct pt_regs *regs, int err)
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struct thread_info *thread = current_thread_info();
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spin_lock_irq(&die_lock);
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ret = __die(str, err, thread, regs);
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add_taint(TAINT_DIE);
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spin_unlock_irq(&die_lock);
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panic("Fatal exception in interrupt");
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panic("Fatal exception");
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if (ret != NOTIFY_STOP)
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void uc32_notify_die(const char *str, struct pt_regs *regs,
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struct siginfo *info, unsigned long err, unsigned long trap)
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if (user_mode(regs)) {
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current->thread.error_code = err;
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current->thread.trap_no = trap;
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force_sig_info(info->si_signo, info, current);
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* bad_mode handles the impossible case in the vectors. If you see one of
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* these, then it's extremely serious, and could mean you have buggy hardware.
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* It never returns, and never tries to sync. We hope that we can at least
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* dump out some state information...
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asmlinkage void bad_mode(struct pt_regs *regs, unsigned int reason)
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printk(KERN_CRIT "Bad mode detected with reason 0x%x\n", reason);
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die("Oops - bad mode", regs, 0);
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void __pte_error(const char *file, int line, unsigned long val)
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printk(KERN_DEFAULT "%s:%d: bad pte %08lx.\n", file, line, val);
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void __pmd_error(const char *file, int line, unsigned long val)
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printk(KERN_DEFAULT "%s:%d: bad pmd %08lx.\n", file, line, val);
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void __pgd_error(const char *file, int line, unsigned long val)
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printk(KERN_DEFAULT "%s:%d: bad pgd %08lx.\n", file, line, val);
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asmlinkage void __div0(void)
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printk(KERN_DEFAULT "Division by zero in kernel.\n");
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EXPORT_SYMBOL(__div0);
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/* if that doesn't kill us, halt */
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panic("Oops failed to kill thread");
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EXPORT_SYMBOL(abort);
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void __init trap_init(void)
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void __init early_trap_init(void)
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unsigned long vectors = VECTORS_BASE;
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* Copy the vectors, stubs (in entry-unicore.S)
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* into the vector page, mapped at 0xffff0000, and ensure these
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* are visible to the instruction stream.
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memcpy((void *)vectors,
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__vectors_end - __vectors_start);
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memcpy((void *)vectors + 0x200,
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__stubs_end - __stubs_start);
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flush_icache_range(vectors, vectors + PAGE_SIZE);