traps_32.c

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/*
 * arch/sparc/kernel/traps.c
 *
 * Copyright 1995, 2008 David S. Miller ([email protected])
 * Copyright 2000 Jakub Jelinek ([email protected])
 */

/*
 * I hate traps on the sparc, grrr...
 */

#include <linux/sched.h>  /* for jiffies */
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/smp.h>
#include <linux/kdebug.h>
#include <linux/export.h>

#include <asm/delay.h>
#include <asm/ptrace.h>
#include <asm/oplib.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/unistd.h>
#include <asm/traps.h>

#include "entry.h"
#include "kernel.h"

/* #define TRAP_DEBUG */

static void instruction_dump(unsigned long *pc)
{
    int i;
    
    if((((unsigned long) pc) & 3))
                return;

    for(i = -3; i < 6; i++)
        printk("%c%08lx%c",i?' ':'<',pc[i],i?' ':'>');
    printk("\n");
}

#define __SAVE __asm__ __volatile__("save %sp, -0x40, %sp\n\t")
#define __RESTORE __asm__ __volatile__("restore %g0, %g0, %g0\n\t")

void die_if_kernel(char *str, struct pt_regs *regs)
{
    static int die_counter;
    int count = 0;

    /* Amuse the user. */
    printk(
"              \\|/ ____ \\|/\n"
"              \"@'/ ,. \\`@\"\n"
"              /_| \\__/ |_\\\n"
"                 \\__U_/\n");

    printk("%s(%d): %s [#%d]\n", current->comm, task_pid_nr(current), str, ++die_counter);
    show_regs(regs);
    add_taint(TAINT_DIE);

    __SAVE; __SAVE; __SAVE; __SAVE;
    __SAVE; __SAVE; __SAVE; __SAVE;
    __RESTORE; __RESTORE; __RESTORE; __RESTORE;
    __RESTORE; __RESTORE; __RESTORE; __RESTORE;

    {
        struct reg_window32 *rw = (struct reg_window32 *)regs->u_regs[UREG_FP];

        /* Stop the back trace when we hit userland or we
         * find some badly aligned kernel stack. Set an upper
         * bound in case our stack is trashed and we loop.
         */
        while(rw                    &&
              count++ < 30              &&
                      (((unsigned long) rw) >= PAGE_OFFSET) &&
              !(((unsigned long) rw) & 0x7)) {
            printk("Caller[%08lx]: %pS\n", rw->ins[7],
                   (void *) rw->ins[7]);
            rw = (struct reg_window32 *)rw->ins[6];
        }
    }
    printk("Instruction DUMP:");
    instruction_dump ((unsigned long *) regs->pc);
    if(regs->psr & PSR_PS)
        do_exit(SIGKILL);
    do_exit(SIGSEGV);
}

void do_hw_interrupt(struct pt_regs *regs, unsigned long type)
{
    siginfo_t info;

    if(type < 0x80) {
        /* Sun OS's puke from bad traps, Linux survives! */
        printk("Unimplemented Sparc TRAP, type = %02lx\n", type);
        die_if_kernel("Whee... Hello Mr. Penguin", regs);
    }   

    if(regs->psr & PSR_PS)
        die_if_kernel("Kernel bad trap", regs);

    info.si_signo = SIGILL;
    info.si_errno = 0;
    info.si_code = ILL_ILLTRP;
    info.si_addr = (void __user *)regs->pc;
    info.si_trapno = type - 0x80;
    force_sig_info(SIGILL, &info, current);
}

void do_illegal_instruction(struct pt_regs *regs, unsigned long pc, unsigned long npc,
                unsigned long psr)
{
    siginfo_t info;

    if(psr & PSR_PS)
        die_if_kernel("Kernel illegal instruction", regs);
#ifdef TRAP_DEBUG
    printk("Ill instr. at pc=%08lx instruction is %08lx\n",
           regs->pc, *(unsigned long *)regs->pc);
#endif

    info.si_signo = SIGILL;
    info.si_errno = 0;
    info.si_code = ILL_ILLOPC;
    info.si_addr = (void __user *)pc;
    info.si_trapno = 0;
    send_sig_info(SIGILL, &info, current);
}

void do_priv_instruction(struct pt_regs *regs, unsigned long pc, unsigned long npc,
             unsigned long psr)
{
    siginfo_t info;

    if(psr & PSR_PS)
        die_if_kernel("Penguin instruction from Penguin mode??!?!", regs);
    info.si_signo = SIGILL;
    info.si_errno = 0;
    info.si_code = ILL_PRVOPC;
    info.si_addr = (void __user *)pc;
    info.si_trapno = 0;
    send_sig_info(SIGILL, &info, current);
}

/* XXX User may want to be allowed to do this. XXX */

void do_memaccess_unaligned(struct pt_regs *regs, unsigned long pc, unsigned long npc,
                unsigned long psr)
{
    siginfo_t info;

    if(regs->psr & PSR_PS) {
        printk("KERNEL MNA at pc %08lx npc %08lx called by %08lx\n", pc, npc,
               regs->u_regs[UREG_RETPC]);
        die_if_kernel("BOGUS", regs);
        /* die_if_kernel("Kernel MNA access", regs); */
    }
#if 0
    show_regs (regs);
    instruction_dump ((unsigned long *) regs->pc);
    printk ("do_MNA!\n");
#endif
    info.si_signo = SIGBUS;
    info.si_errno = 0;
    info.si_code = BUS_ADRALN;
    info.si_addr = /* FIXME: Should dig out mna address */ (void *)0;
    info.si_trapno = 0;
    send_sig_info(SIGBUS, &info, current);
}

static unsigned long init_fsr = 0x0UL;
static unsigned long init_fregs[32] __attribute__ ((aligned (8))) =
                { ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL,
          ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL,
          ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL,
          ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL };

void do_fpd_trap(struct pt_regs *regs, unsigned long pc, unsigned long npc,
         unsigned long psr)
{
    /* Sanity check... */
    if(psr & PSR_PS)
        die_if_kernel("Kernel gets FloatingPenguinUnit disabled trap", regs);

    put_psr(get_psr() | PSR_EF);    /* Allow FPU ops. */
    regs->psr |= PSR_EF;
#ifndef CONFIG_SMP
    if(last_task_used_math == current)
        return;
    if(last_task_used_math) {
        /* Other processes fpu state, save away */
        struct task_struct *fptask = last_task_used_math;
        fpsave(&fptask->thread.float_regs[0], &fptask->thread.fsr,
               &fptask->thread.fpqueue[0], &fptask->thread.fpqdepth);
    }
    last_task_used_math = current;
    if(used_math()) {
        fpload(&current->thread.float_regs[0], &current->thread.fsr);
    } else {
        /* Set initial sane state. */
        fpload(&init_fregs[0], &init_fsr);
        set_used_math();
    }
#else
    if(!used_math()) {
        fpload(&init_fregs[0], &init_fsr);
        set_used_math();
    } else {
        fpload(&current->thread.float_regs[0], &current->thread.fsr);
    }
    set_thread_flag(TIF_USEDFPU);
#endif
}

static unsigned long fake_regs[32] __attribute__ ((aligned (8)));
static unsigned long fake_fsr;
static unsigned long fake_queue[32] __attribute__ ((aligned (8)));
static unsigned long fake_depth;

extern int do_mathemu(struct pt_regs *, struct task_struct *);

void do_fpe_trap(struct pt_regs *regs, unsigned long pc, unsigned long npc,
         unsigned long psr)
{
    static int calls;
    siginfo_t info;
    unsigned long fsr;
    int ret = 0;
#ifndef CONFIG_SMP
    struct task_struct *fpt = last_task_used_math;
#else
    struct task_struct *fpt = current;
#endif
    put_psr(get_psr() | PSR_EF);
    /* If nobody owns the fpu right now, just clear the
     * error into our fake static buffer and hope it don't
     * happen again.  Thank you crashme...
     */
#ifndef CONFIG_SMP
    if(!fpt) {
#else
    if (!test_tsk_thread_flag(fpt, TIF_USEDFPU)) {
#endif
        fpsave(&fake_regs[0], &fake_fsr, &fake_queue[0], &fake_depth);
        regs->psr &= ~PSR_EF;
        return;
    }
    fpsave(&fpt->thread.float_regs[0], &fpt->thread.fsr,
           &fpt->thread.fpqueue[0], &fpt->thread.fpqdepth);
#ifdef DEBUG_FPU
    printk("Hmm, FP exception, fsr was %016lx\n", fpt->thread.fsr);
#endif

    switch ((fpt->thread.fsr & 0x1c000)) {
    /* switch on the contents of the ftt [floating point trap type] field */
#ifdef DEBUG_FPU
    case (1 << 14):
        printk("IEEE_754_exception\n");
        break;
#endif
    case (2 << 14):  /* unfinished_FPop (underflow & co) */
    case (3 << 14):  /* unimplemented_FPop (quad stuff, maybe sqrt) */
        ret = do_mathemu(regs, fpt);
        break;
#ifdef DEBUG_FPU
    case (4 << 14):
        printk("sequence_error (OS bug...)\n");
        break;
    case (5 << 14):
        printk("hardware_error (uhoh!)\n");
        break;
    case (6 << 14):
        printk("invalid_fp_register (user error)\n");
        break;
#endif /* DEBUG_FPU */
    }
    /* If we successfully emulated the FPop, we pretend the trap never happened :-> */
    if (ret) {
        fpload(&current->thread.float_regs[0], &current->thread.fsr);
        return;
    }
    /* nope, better SIGFPE the offending process... */
           
#ifdef CONFIG_SMP
    clear_tsk_thread_flag(fpt, TIF_USEDFPU);
#endif
    if(psr & PSR_PS) {
        /* The first fsr store/load we tried trapped,
         * the second one will not (we hope).
         */
        printk("WARNING: FPU exception from kernel mode. at pc=%08lx\n",
               regs->pc);
        regs->pc = regs->npc;
        regs->npc += 4;
        calls++;
        if(calls > 2)
            die_if_kernel("Too many Penguin-FPU traps from kernel mode",
                      regs);
        return;
    }

    fsr = fpt->thread.fsr;
    info.si_signo = SIGFPE;
    info.si_errno = 0;
    info.si_addr = (void __user *)pc;
    info.si_trapno = 0;
    info.si_code = __SI_FAULT;
    if ((fsr & 0x1c000) == (1 << 14)) {
        if (fsr & 0x10)
            info.si_code = FPE_FLTINV;
        else if (fsr & 0x08)
            info.si_code = FPE_FLTOVF;
        else if (fsr & 0x04)
            info.si_code = FPE_FLTUND;
        else if (fsr & 0x02)
            info.si_code = FPE_FLTDIV;
        else if (fsr & 0x01)
            info.si_code = FPE_FLTRES;
    }
    send_sig_info(SIGFPE, &info, fpt);
#ifndef CONFIG_SMP
    last_task_used_math = NULL;
#endif
    regs->psr &= ~PSR_EF;
    if(calls > 0)
        calls=0;
}

void handle_tag_overflow(struct pt_regs *regs, unsigned long pc, unsigned long npc,
             unsigned long psr)
{
    siginfo_t info;

    if(psr & PSR_PS)
        die_if_kernel("Penguin overflow trap from kernel mode", regs);
    info.si_signo = SIGEMT;
    info.si_errno = 0;
    info.si_code = EMT_TAGOVF;
    info.si_addr = (void __user *)pc;
    info.si_trapno = 0;
    send_sig_info(SIGEMT, &info, current);
}

void handle_watchpoint(struct pt_regs *regs, unsigned long pc, unsigned long npc,
               unsigned long psr)
{
#ifdef TRAP_DEBUG
    printk("Watchpoint detected at PC %08lx NPC %08lx PSR %08lx\n",
           pc, npc, psr);
#endif
    if(psr & PSR_PS)
        panic("Tell me what a watchpoint trap is, and I'll then deal "
              "with such a beast...");
}

void handle_reg_access(struct pt_regs *regs, unsigned long pc, unsigned long npc,
               unsigned long psr)
{
    siginfo_t info;

#ifdef TRAP_DEBUG
    printk("Register Access Exception at PC %08lx NPC %08lx PSR %08lx\n",
           pc, npc, psr);
#endif
    info.si_signo = SIGBUS;
    info.si_errno = 0;
    info.si_code = BUS_OBJERR;
    info.si_addr = (void __user *)pc;
    info.si_trapno = 0;
    force_sig_info(SIGBUS, &info, current);
}

void handle_cp_disabled(struct pt_regs *regs, unsigned long pc, unsigned long npc,
            unsigned long psr)
{
    siginfo_t info;

    info.si_signo = SIGILL;
    info.si_errno = 0;
    info.si_code = ILL_COPROC;
    info.si_addr = (void __user *)pc;
    info.si_trapno = 0;
    send_sig_info(SIGILL, &info, current);
}

void handle_cp_exception(struct pt_regs *regs, unsigned long pc, unsigned long npc,
             unsigned long psr)
{
    siginfo_t info;

#ifdef TRAP_DEBUG
    printk("Co-Processor Exception at PC %08lx NPC %08lx PSR %08lx\n",
           pc, npc, psr);
#endif
    info.si_signo = SIGILL;
    info.si_errno = 0;
    info.si_code = ILL_COPROC;
    info.si_addr = (void __user *)pc;
    info.si_trapno = 0;
    send_sig_info(SIGILL, &info, current);
}

void handle_hw_divzero(struct pt_regs *regs, unsigned long pc, unsigned long npc,
               unsigned long psr)
{
    siginfo_t info;

    info.si_signo = SIGFPE;
    info.si_errno = 0;
    info.si_code = FPE_INTDIV;
    info.si_addr = (void __user *)pc;
    info.si_trapno = 0;
    send_sig_info(SIGFPE, &info, current);
}

#ifdef CONFIG_DEBUG_BUGVERBOSE
void do_BUG(const char *file, int line)
{
        // bust_spinlocks(1);   XXX Not in our original BUG()
        printk("kernel BUG at %s:%d!\n", file, line);
}
EXPORT_SYMBOL(do_BUG);
#endif

/* Since we have our mappings set up, on multiprocessors we can spin them
 * up here so that timer interrupts work during initialization.
 */

void trap_init(void)
{
    extern void thread_info_offsets_are_bolixed_pete(void);

    /* Force linker to barf if mismatched */
    if (TI_UWINMASK    != offsetof(struct thread_info, uwinmask) ||
        TI_TASK        != offsetof(struct thread_info, task) ||
        TI_EXECDOMAIN  != offsetof(struct thread_info, exec_domain) ||
        TI_FLAGS       != offsetof(struct thread_info, flags) ||
        TI_CPU         != offsetof(struct thread_info, cpu) ||
        TI_PREEMPT     != offsetof(struct thread_info, preempt_count) ||
        TI_SOFTIRQ     != offsetof(struct thread_info, softirq_count) ||
        TI_HARDIRQ     != offsetof(struct thread_info, hardirq_count) ||
        TI_KSP         != offsetof(struct thread_info, ksp) ||
        TI_KPC         != offsetof(struct thread_info, kpc) ||
        TI_KPSR        != offsetof(struct thread_info, kpsr) ||
        TI_KWIM        != offsetof(struct thread_info, kwim) ||
        TI_REG_WINDOW  != offsetof(struct thread_info, reg_window) ||
        TI_RWIN_SPTRS  != offsetof(struct thread_info, rwbuf_stkptrs) ||
        TI_W_SAVED     != offsetof(struct thread_info, w_saved))
        thread_info_offsets_are_bolixed_pete();

    /* Attach to the address space of init_task. */
    atomic_inc(&init_mm.mm_count);
    current->active_mm = &init_mm;

    /* NOTE: Other cpus have this done as they are started
     *       up on SMP.
     */
}