traps.c

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/*
 *  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/uaccess.h>
#include <asm/io.h>
#include <linux/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);
extern void smp_call_function_single_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

static 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;    /* CPU_BOOT_IPI */
    eit_vector[190] = (unsigned long)smp_call_function_single_interrupt;
    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();
}

static int kstack_depth_to_print = 24;

static 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");
}

static 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);
    }
}