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/*

 *  linux/arch/arm/kernel/traps.c

 *

 *  Copyright (C) 1995, 1996 Russell King

 *  Fragments that appear the same as linux/arch/i386/kernel/traps.c (C) Linus Torvalds

 */

/*

 * 'traps.c' handles hardware exceptions after we have saved some state in

 * 'linux/arch/arm/lib/traps.S'.  Mostly a debugging aid, but will probably

 * kill the offending process.

 */

#include <linux/config.h>

#include <linux/types.h>

#include <linux/kernel.h>

#include <linux/signal.h>

#include <linux/sched.h>

#include <linux/mm.h>

extern void fpe_save(struct fp_soft_struct *);

extern void fpe_restore(struct fp_soft_struct *);

extern void die_if_kernel(char *str, struct pt_regs *regs, int err, int ret);

extern void c_backtrace (unsigned long fp, int pmode);

extern int ptrace_cancel_bpt (struct task_struct *);

char *processor_modes[]=

{ "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,

  "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",

  "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "UK6_32" , "ABT_32" ,

  "UK8_32" , "UK9_32" , "UK10_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"

};

static char *handler[]= { "prefetch abort", "data abort", "address exception", "interrupt" };

static inline void console_verbose(void)

{

        extern int console_loglevel;

        console_loglevel = 15;

}

int kstack_depth_to_print = 200;

static int verify_stack_pointer (unsigned long stackptr, int size)

{

#if defined(CONFIG_CPU_ARM2) || defined(CONFIG_CPU_ARM3)

        if (stackptr < 0x02048000 || stackptr + size > 0x03000000)

                return -EFAULT;

#else

        if (stackptr < 0xc0000000 || stackptr + size > high_memory)

                return -EFAULT;

#endif

                return 0;

}

static void dump_stack (unsigned long *start, unsigned long *end, int offset, int max)

{

        unsigned long *p;

        int i;

        for (p = start + offset, i = 0; i < max && p < end; i++, p++) {

                if (i && (i & 7) == 0)

                        printk ("\n       ");

                printk ("%08lx ", *p);

        }

        printk ("\n");

}

/*

 * These constants are for searching for possible module text

 * segments.  VMALLOC_OFFSET comes from mm/vmalloc.c; MODULE_RANGE is

 * a guess of how much space is likely to be vmalloced.

 */

#define VMALLOC_OFFSET (8*1024*1024)

#define MODULE_RANGE (8*1024*1024)

static void dump_instr (unsigned long pc)

{

        unsigned long module_start, module_end;

        int pmin = -2, pmax = 3, ok = 0;

        extern char start_kernel, _etext;

        module_start = ((high_memory + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1));

        module_end   = module_start + MODULE_RANGE;

        if ((pc >= (unsigned long) &start_kernel) &&

            (pc <= (unsigned long) &_etext)) {

                if (pc + pmin < (unsigned long) &start_kernel)

                        pmin = ((unsigned long) &start_kernel) - pc;

                if (pc + pmax > (unsigned long) &_etext)

                        pmax = ((unsigned long) &_etext) - pc;

                ok = 1;

        } else if (pc >= module_start && pc <= module_end) {

                if (pc + pmin < module_start)

                        pmin = module_start - pc;

                if (pc + pmax > module_end)

                        pmax = module_end - pc;

                ok = 1;

        }

        printk ("Code: ");

        if (ok) {

                int i;

                for (i = pmin; i < pmax; i++)

                        printk("%08lx ", ((unsigned long *)pc)[i]);

                printk ("\n");

        } else

                printk ("pc not in code space\n");

}

/*

 * This function is protected against kernel-mode re-entrancy.  If it

 * is re-entered it will hang the system since we can't guarantee in

 * this case that any of the functions that it calls are safe any more.

 * Even the panic function could be a problem, but we'll give it a go.

 */

void die_if_kernel(char *str, struct pt_regs *regs, int err, int ret)

{

        static int died = 0;

        unsigned long cstack, sstack, frameptr;

        if (user_mode(regs))

                return;

        switch (died) {

        case 2:

                while (1);

        case 1:

                died ++;

                panic ("die_if_kernel re-entered.  Major kernel corruption.  Please reboot me!");

                break;

        case 0:

                died ++;

                break;

        }

        console_verbose ();

        printk ("Internal error: %s: %x\n", str, err);

        printk ("CPU: %d", smp_processor_id());

        show_regs (regs);

        printk ("Process %s (pid: %d, stackpage=%08lx)\nStack: ",

                current->comm, current->pid, current->kernel_stack_page);

        cstack = (unsigned long)(regs + 1);

        sstack = (unsigned long)current->kernel_stack_page;

        if (*(unsigned long *)sstack != STACK_MAGIC)

                printk ("*** corrupted stack page\n       ");

        if (verify_stack_pointer (cstack, 4))

                printk ("%08lx invalid kernel stack pointer\n", cstack);

        else if(cstack > sstack + 4096)

                printk("(sp overflow)\n");

        else if(cstack < sstack)

                printk("(sp underflow)\n");

        else

                dump_stack ((unsigned long *)sstack, (unsigned long *)sstack + 1024,

                        cstack - sstack, kstack_depth_to_print);

        frameptr = regs->ARM_fp;

        if (frameptr) {

                if (verify_stack_pointer (frameptr, 4))

                        printk ("Backtrace: invalid frame pointer\n");

                else {

                        printk("Backtrace: \n");

                        c_backtrace (frameptr, processor_mode(regs));

                }

        }

        dump_instr (instruction_pointer(regs));

        died = 0;

        if (ret != -1)

                do_exit (ret);

        else {

                cli ();

                while (1);

        }

}

void bad_user_access_alignment (const void *ptr)

{

        void *pc;

        __asm__("mov %0, lr\n": "=r" (pc));

        printk ("bad_user_access_alignment called: ptr = %p, pc = %p\n", ptr, pc);

        current->tss.error_code = 0;

        current->tss.trap_no = 11;

        force_sig (SIGBUS, current);

/*      die_if_kernel("Oops - bad user access alignment", regs, mode, SIGBUS);*/

}

asmlinkage void do_undefinstr (int address, struct pt_regs *regs, int mode)

{

        current->tss.error_code = 0;

        current->tss.trap_no = 6;

        force_sig (SIGILL, current);

        die_if_kernel("Oops - undefined instruction", regs, mode, SIGILL);

}

asmlinkage void do_excpt (int address, struct pt_regs *regs, int mode)

{

        current->tss.error_code = 0;

        current->tss.trap_no = 11;

        force_sig (SIGBUS, current);

        die_if_kernel("Oops - address exception", regs, mode, SIGBUS);

}

asmlinkage void do_unexp_fiq (struct pt_regs *regs)

{

#ifndef CONFIG_IGNORE_FIQ

        printk ("Hmm.  Unexpected FIQ received, but trying to continue\n");

        printk ("You may have a hardware problem...\n");

#endif

}

asmlinkage void bad_mode(struct pt_regs *regs, int reason, int proc_mode)

{

        printk ("Bad mode in %s handler detected: mode %s\n",

                handler[reason],

                processor_modes[proc_mode]);

        die_if_kernel ("Oops", regs, 0, -1);

}

/*

 * 'math_state_restore()' saves the current math information in the

 * old math state array, and gets the new ones from the current task.

 *

 * We no longer save/restore the math state on every context switch

 * any more.  We only do this now if it actually gets used.

 */

asmlinkage void math_state_restore (void)

{

        if (last_task_used_math == current)

                return;

        if (last_task_used_math)

                /*

                 * Save current fp state into last_task_used_math->tss.fpe_save

                 */

                fpe_save (&last_task_used_math->tss.fpstate.soft);

        last_task_used_math = current;

        if (current->used_math) {

                /*

                 * Restore current fp state from current->tss.fpe_save

                 */

                fpe_restore (&current->tss.fpstate.soft);

        } else {

                /*

                 * initialise fp state

                 */

                fpe_restore (&init_task.tss.fpstate.soft);

                current->used_math = 1;

        }

}

asmlinkage void arm_syscall (int no, struct pt_regs *regs)

{

        switch (no) {

        case 0: /* branch through 0 */

                printk ("[%d] %s: branch through zero\n", current->pid, current->comm);

                force_sig (SIGILL, current);

                if (user_mode(regs)) {

                        show_regs (regs);

                        c_backtrace (regs->ARM_fp, processor_mode(regs));

                }

                die_if_kernel ("Oops", regs, 0, SIGILL);

                break;

        case 1: /* SWI_BREAK_POINT */

                regs->ARM_pc -= 4; /* Decrement PC by one instruction */

                ptrace_cancel_bpt (current);

                force_sig (SIGTRAP, current);

                break;

        default:

                printk ("[%d] %s: arm syscall %d\n", current->pid, current->comm, no);

                force_sig (SIGILL, current);

                if (user_mode(regs)) {

                        show_regs (regs);

                        c_backtrace (regs->ARM_fp, processor_mode(regs));

                }

                die_if_kernel ("Oops", regs, no, SIGILL);

                break;

        }

}

asmlinkage void deferred(int n, struct pt_regs *regs)

{

        printk ("[%d] %s: old system call %X\n", current->pid, current->comm, n);

        show_regs (regs);

        force_sig (SIGILL, current);

}

asmlinkage void arm_malalignedptr(const char *str, void *pc, volatile void *ptr)

{

        printk ("Mal-aligned pointer in %s: %p (PC=%p)\n", str, ptr, pc);

}

asmlinkage void arm_invalidptr (const char *function, int size)

{

        printk ("Invalid pointer size in %s (PC=%p) size %d\n",

                function, __builtin_return_address(0), size);

}