Import 2.3.18pre1

[davej-history.git] / arch / arm / kernel / traps.c

/*
 *  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>
#include <linux/spinlock.h>

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

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;

/*
 * Stack pointers should always be within the kernels view of
 * physical memory.  If it is not there, then we can't dump
 * out any information relating to the stack.
 */
static int verify_stack(unsigned long sp)
{
        if (sp < PAGE_OFFSET || sp > (unsigned long)high_memory)
                return -EFAULT;

        return 0;
}

/*
 * Dump out the contents of some memory nicely...
 */
void dump_mem(unsigned long bottom, unsigned long top)
{
        unsigned long p = bottom & ~31;
        int i;

        for (p = bottom & ~31; p < top;) {
                printk("%08lx: ", p);

                for (i = 0; i < 8; i++, p += 4) {
                        if (p < bottom || p >= top)
                                printk("         ");
                        else
                                printk("%08lx ", *(unsigned long *)p);
                        if (i == 3)
                                printk(" ");
                }
                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, int user)
{
        int pmin = -2, pmax = 3, ok = 0;
        extern char start_kernel, _etext;

        if (!user) {
                unsigned long module_start, module_end;
                unsigned long kernel_start, kernel_end;

                module_start = VMALLOC_START;
                module_end   = module_start + MODULE_RANGE;

                kernel_start = (unsigned long)&start_kernel;
                kernel_end   = (unsigned long)&_etext;

                if (pc >= kernel_start && pc < kernel_end) {
                        if (pc + pmin < kernel_start)
                                pmin = kernel_start - pc;
                        if (pc + pmax > kernel_end)
                                pmax = kernel_end - 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;
                }
        } else
                ok = verify_area(VERIFY_READ, (void *)(pc + pmin), pmax - pmin) == 0;

        printk ("Code: ");
        if (ok) {
                int i;
                for (i = pmin; i < pmax; i++)
                        printk(i == 0 ? "(%08lx) " : "%08lx ", ((unsigned long *)pc)[i]);
                printk ("\n");
        } else
                printk ("pc not in code space\n");
}

spinlock_t die_lock;

/*
 * This function is protected against re-entrancy.
 */
void die(const char *str, struct pt_regs *regs, int err)
{
        struct task_struct *tsk = current;

        spin_lock_irq(&die_lock);

        console_verbose();
        printk("Internal error: %s: %x\n", str, err);
        printk("CPU: %d\n", smp_processor_id());
        show_regs(regs);
        printk("Process %s (pid: %d, stackpage=%08lx)\n",
                current->comm, current->pid, 4096+(unsigned long)tsk);

        if (!user_mode(regs)) {
                unsigned long sp = (unsigned long)(regs + 1);
                unsigned long fp;
                int dump_info = 1;

                printk("Stack: ");
                if (verify_stack(sp)) {
                        printk("invalid kernel stack pointer %08lx", sp);
                        dump_info = 0;
                } else if (sp < 4096+(unsigned long)tsk)
                        printk("kernel stack pointer underflow");
                printk("\n");

                if (dump_info)
                        dump_mem(sp - 16, 8192+(unsigned long)tsk);

                dump_info = 1;

                printk("Backtrace: ");
                fp = regs->ARM_fp;
                if (!fp) {
                        printk("no frame pointer");
                        dump_info = 0;
                } else if (verify_stack(fp)) {
                        printk("invalid frame pointer %08lx", fp);
                        dump_info = 0;
                } else if (fp < 4096+(unsigned long)tsk)
                        printk("frame pointer underflow");
                printk("\n");

                if (dump_info)
                        c_backtrace(fp, processor_mode(regs));

                dump_instr(instruction_pointer(regs), 0);
        }

        spin_unlock_irq(&die_lock);     
}

static void die_if_kernel(const char *str, struct pt_regs *regs, int err)
{
        if (user_mode(regs))
                return;

        die(str, regs, err);
}

void bad_user_access_alignment(const void *ptr)
{
        printk(KERN_ERR "bad user access alignment: ptr = %p, pc = %p\n", ptr, 
                __builtin_return_address(0));
        current->thread.error_code = 0;
        current->thread.trap_no = 11;
        force_sig(SIGBUS, current);
/*      die_if_kernel("Oops - bad user access alignment", regs, mode);*/
}

asmlinkage void do_undefinstr(int address, struct pt_regs *regs, int mode)
{
#ifdef CONFIG_DEBUG_USER
        printk(KERN_INFO "%s (%d): undefined instruction: pc=%08lx\n",
                current->comm, current->pid, instruction_pointer(regs));
#endif
        current->thread.error_code = 0;
        current->thread.trap_no = 6;
        force_sig(SIGILL, current);
        die_if_kernel("Oops - undefined instruction", regs, mode);
}

asmlinkage void do_excpt(int address, struct pt_regs *regs, int mode)
{
#ifdef CONFIG_DEBUG_USER
        printk(KERN_INFO "%s (%d): address exception: pc=%08lx\n",
                current->comm, current->pid, instruction_pointer(regs));
#endif
        current->thread.error_code = 0;
        current->thread.trap_no = 11;
        force_sig(SIGBUS, current);
        die_if_kernel("Oops - address exception", regs, mode);
}

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
}

/*
 * bad_mode handles the impossible case in the vectors.
 * If you see one of these, then it's extremely serious,
 * and could mean you have buggy hardware.  It never
 * returns, and never tries to sync.  We hope that we
 * can dump out some state information...
 */
asmlinkage void bad_mode(struct pt_regs *regs, int reason, int proc_mode)
{
        console_verbose();

        printk(KERN_CRIT "Bad mode in %s handler detected: mode %s\n",
                handler[reason], processor_modes[proc_mode]);

        /*
         * Dump out the vectors and stub routines
         */
        printk(KERN_CRIT "Vectors:\n");
        dump_mem(0, 0x40);
        printk(KERN_CRIT "Stubs:\n");
        dump_mem(0x200, 0x4b8);

        die("Oops", regs, 0);
        cli();
        while(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)
{
        current->used_math = 1;
}

asmlinkage int arm_syscall (int no, struct pt_regs *regs)
{
        switch (no) {
        case 0: /* branch through 0 */
                force_sig(SIGSEGV, current);
                die_if_kernel("branch through zero", regs, 0);
                break;

        case 1: /* SWI_BREAK_POINT */
                regs->ARM_pc -= 4; /* Decrement PC by one instruction */
                ptrace_cancel_bpt(current);
                force_sig(SIGTRAP, current);
                return regs->ARM_r0;

        case 2: /* sys_cacheflush */
#ifdef CONFIG_CPU_32
                /* r0 = start, r1 = length, r2 = flags */
                cpu_flush_cache_area(regs->ARM_r0, regs->ARM_r1, 1);
#endif
                break;

        default:
                /* Calls 9f00xx..9f07ff are defined to return -ENOSYS
                   if not implemented, rather than raising SIGILL.  This
                   way the calling program can gracefully determine whether
                   a feature is supported.  */
                if (no <= 0x7ff)
                        return -ENOSYS;
#ifdef CONFIG_DEBUG_USER
                /* experiance shows that these seem to indicate that
                 * something catastrophic has happened
                 */
                printk("[%d] %s: arm syscall %d\n", current->pid, current->comm, no);
                if (user_mode(regs)) {
                        show_regs(regs);
                        c_backtrace(regs->ARM_fp, processor_mode(regs));
                }
#endif
                force_sig(SIGILL, current);
                die_if_kernel("Oops", regs, no);
                break;
        }
        return 0;
}

asmlinkage void deferred(int n, struct pt_regs *regs)
{
        /* You might think just testing `handler' would be enough, but PER_LINUX
         * points it to no_lcall7 to catch undercover SVr4 binaries.  Gutted.
         */
        if (current->personality != PER_LINUX && current->exec_domain->handler) {
                /* Hand it off to iBCS.  The extra parameter and consequent type 
                 * forcing is necessary because of the weird ARM calling convention.
                 */
                void (*handler)(int nr, struct pt_regs *regs) = (void *)current->exec_domain->handler;
                (*handler)(n, regs);
                return;
        }

#ifdef CONFIG_DEBUG_USER
        printk(KERN_ERR "[%d] %s: old system call.\n", current->pid, 
               current->comm);
#endif
        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);
}

#ifdef CONFIG_CPU_26
asmlinkage void baddataabort(int code, unsigned long instr, struct pt_regs *regs)
{
        unsigned long phys, addr = instruction_pointer(regs);

#ifdef CONFIG_DEBUG_ERRORS
        printk("pid=%d\n", current->pid);

        show_regs(regs);
        dump_instr(instruction_pointer(regs), 1);
        {
                pgd_t *pgd;

                printk ("current->thread.memmap = %08lX\n", current->thread.memmap);
                pgd = pgd_offset(current->mm, addr);
                printk ("*pgd = %08lx", pgd_val (*pgd));
                if (!pgd_none (*pgd)) {
                        pmd_t *pmd;
                        pmd = pmd_offset (pgd, addr);
                        printk (", *pmd = %08lx", pmd_val (*pmd));
                        if (!pmd_none (*pmd)) {
                                unsigned long ptr = pte_page(*pte_offset(pmd, addr));
                                printk (", *pte = %08lx", pte_val (*pte_offset (pmd, addr)));
                                phys = ptr + (addr & 0x7fff);
                        }
                }
                printk ("\n");
        }
#endif
        panic("unknown data abort code %d [pc=%08lx *pc=%08lx lr=%08lx sp=%08lx]",
                code, regs->ARM_pc, instr, regs->ARM_lr, regs->ARM_sp);
}
#endif

asmlinkage void __div0(void)
{
        printk("Awooga, division by zero in kernel.\n");
        __backtrace();
}