traps.c

linux-2.4.29操作系统的源码

        show_regs(regs);
	bust_spinlocks(0);
        spin_unlock_irq(&die_lock);
        do_exit(SIGSEGV);
}

static void inline do_trap(long interruption_code, int signr, char *str,
                           struct pt_regs *regs, siginfo_t *info)
{
	/*
	 * We got all needed information from the lowcore and can
	 * now safely switch on interrupts.
	 */
	if (regs->psw.mask & PSW_PROBLEM_STATE)
		__sti();

        if (regs->psw.mask & PSW_PROBLEM_STATE) {
                struct task_struct *tsk = current;
                tsk->thread.trap_no = interruption_code & 0xffff;
		if (info)
			force_sig_info(signr, info, tsk);
		else
                	force_sig(signr, tsk);
#ifndef CONFIG_SYSCTL
#ifdef CONFIG_PROCESS_DEBUG
                printk("User process fault: interruption code 0x%lX\n",
                       interruption_code);
                show_regs(regs);
#endif
#else
		if (sysctl_userprocess_debug) {
			printk("User process fault: interruption code 0x%lX\n",
			       interruption_code);
			show_regs(regs);
		}
#endif
        } else {
                unsigned long fixup = search_exception_table(regs->psw.addr);
                if (fixup)
                        regs->psw.addr = fixup;
                else
                        die(str, regs, interruption_code);
        }
}

static inline void *get_check_address(struct pt_regs *regs)
{
	return (void *) ADDR_BITS_REMOVE(regs->psw.addr-S390_lowcore.pgm_ilc);
}

int do_debugger_trap(struct pt_regs *regs,int signal)
{
	if(regs->psw.mask&PSW_PROBLEM_STATE)
	{
		if(current->ptrace & PT_PTRACED)
			force_sig(signal,current);
		else
			return 1;
	}
	else
	{
#if CONFIG_REMOTE_DEBUG
		if(gdb_stub_initialised)
		{
			gdb_stub_handle_exception(regs, signal);
			return 0;
		}
#endif
		return 1;
	}
	return 0;
}

#define DO_ERROR(signr, str, name) \
asmlinkage void name(struct pt_regs * regs, long interruption_code) \
{ \
	do_trap(interruption_code, signr, str, regs, NULL); \
}

#define DO_ERROR_INFO(signr, str, name, sicode, siaddr) \
asmlinkage void name(struct pt_regs * regs, long interruption_code) \
{ \
        siginfo_t info; \
        info.si_signo = signr; \
        info.si_errno = 0; \
        info.si_code = sicode; \
        info.si_addr = (void *)siaddr; \
        do_trap(interruption_code, signr, str, regs, &info); \
}

DO_ERROR(SIGSEGV, "Unknown program exception", default_trap_handler)

DO_ERROR_INFO(SIGBUS, "addressing exception", addressing_exception,
	      BUS_ADRERR, get_check_address(regs))
DO_ERROR_INFO(SIGILL,  "execute exception", execute_exception,
	      ILL_ILLOPN, get_check_address(regs))
DO_ERROR_INFO(SIGFPE,  "fixpoint divide exception", divide_exception,
	      FPE_INTDIV, get_check_address(regs))
DO_ERROR_INFO(SIGILL,  "operand exception", operand_exception,
	      ILL_ILLOPN, get_check_address(regs))
DO_ERROR_INFO(SIGILL,  "privileged operation", privileged_op,
	      ILL_PRVOPC, get_check_address(regs))
DO_ERROR_INFO(SIGILL,  "special operation exception", special_op_exception,
	      ILL_ILLOPN, get_check_address(regs))
DO_ERROR_INFO(SIGILL,  "specification exception", specification_exception,
	      ILL_ILLOPN, get_check_address(regs))
DO_ERROR_INFO(SIGILL,  "translation exception", translation_exception,
	      ILL_ILLOPN, get_check_address(regs))

static inline void
do_fp_trap(struct pt_regs *regs, void *location,
           int fpc, long interruption_code)
{
	siginfo_t si;

	si.si_signo = SIGFPE;
	si.si_errno = 0;
	si.si_addr = location;
	si.si_code = 0;
	/* FPC[2] is Data Exception Code */
	if ((fpc & 0x00000300) == 0) {
		/* bits 6 and 7 of DXC are 0 iff IEEE exception */
		if (fpc & 0x8000) /* invalid fp operation */
			si.si_code = FPE_FLTINV;
		else if (fpc & 0x4000) /* div by 0 */
			si.si_code = FPE_FLTDIV;
		else if (fpc & 0x2000) /* overflow */
			si.si_code = FPE_FLTOVF;
		else if (fpc & 0x1000) /* underflow */
			si.si_code = FPE_FLTUND;
		else if (fpc & 0x0800) /* inexact */
			si.si_code = FPE_FLTRES;
	}
	current->thread.ieee_instruction_pointer = (addr_t) location;
	do_trap(interruption_code, SIGFPE,
		"floating point exception", regs, &si);
}

asmlinkage void illegal_op(struct pt_regs * regs, long interruption_code)
{
        __u8 opcode[6];
	__u16 *location;
	int do_sig = 0;

	location = (__u16 *) get_check_address(regs);

	/*
	 * We got all needed information from the lowcore and can
	 * now safely switch on interrupts.
	 */
	if (regs->psw.mask & PSW_PROBLEM_STATE)
		__sti();

	/* WARNING don't change this check back to */
	/* int problem_state=(regs->psw.mask & PSW_PROBLEM_STATE); */
	/* & then doing if(problem_state) an int is too small for this */
	/* check on 64 bit. */
	if(regs->psw.mask & PSW_PROBLEM_STATE)
		get_user(*((__u16 *) opcode), location);
	else
		*((__u16 *)opcode)=*((__u16 *)location);
	if(*((__u16 *)opcode)==S390_BREAKPOINT_U16)
        {
		if(do_debugger_trap(regs,SIGTRAP))
			do_sig=1;
	}
	else
		do_sig = 1;
	if (do_sig)
		do_trap(interruption_code, SIGILL,
			"illegal operation", regs, NULL);
}

asmlinkage void data_exception(struct pt_regs * regs, long interruption_code)
{
	__u16 *location;

	location = (__u16 *) get_check_address(regs);

	/*
	 * We got all needed information from the lowcore and can
	 * now safely switch on interrupts.
	 */
	if (regs->psw.mask & PSW_PROBLEM_STATE)
		__sti();

	__asm__ volatile ("stfpc %0\n\t" 
			  : "=m" (current->thread.fp_regs.fpc));

	if (current->thread.fp_regs.fpc & FPC_DXC_MASK)
		do_fp_trap(regs, location,
                           current->thread.fp_regs.fpc, interruption_code);
        else {
		siginfo_t info;
		info.si_signo = SIGILL;
		info.si_errno = 0;
		info.si_code = ILL_ILLOPN;
		info.si_addr = location;
		do_trap(interruption_code, SIGILL, 
			"data exception", regs, &info);
	}
}



/* init is done in lowcore.S and head.S */

void __init trap_init(void)
{
        int i;

        for (i = 0; i < 128; i++)
          pgm_check_table[i] = &default_trap_handler;
        pgm_check_table[1] = &illegal_op;
        pgm_check_table[2] = &privileged_op;
        pgm_check_table[3] = &execute_exception;
        pgm_check_table[4] = &do_protection_exception;
        pgm_check_table[5] = &addressing_exception;
        pgm_check_table[6] = &specification_exception;
        pgm_check_table[7] = &data_exception;
        pgm_check_table[9] = &divide_exception;
        pgm_check_table[0x12] = &translation_exception;
        pgm_check_table[0x13] = &special_op_exception;
        pgm_check_table[0x15] = &operand_exception;
        pgm_check_table[0x10] = &do_segment_exception;
        pgm_check_table[0x11] = &do_page_exception;
        pgm_check_table[0x1C] = &privileged_op;
        pgm_check_table[0x38] = &addressing_exception;
        pgm_check_table[0x3B] = &do_region_exception;
#ifdef CONFIG_PFAULT
	if (MACHINE_IS_VM) {
		/* request the 0x2603 external interrupt */
		if (register_early_external_interrupt(0x2603, pfault_interrupt,
						      &ext_int_pfault) != 0)
			panic("Couldn't request external interrupt 0x2603");
		/*
		 * Try to get pfault pseudo page faults going.
		 */
		if (pfault_init() != 0) {
			/* Tough luck, no pfault. */
			unregister_early_external_interrupt(0x2603,
							    pfault_interrupt,
							    &ext_int_pfault);
		}
	}
#endif
}


void handle_per_exception(struct pt_regs *regs)
{
	if(regs->psw.mask&PSW_PROBLEM_STATE)
	{
		per_struct *per_info=&current->thread.per_info;
		per_info->lowcore.words.perc_atmid=S390_lowcore.per_perc_atmid;
		per_info->lowcore.words.address=S390_lowcore.per_address;
		per_info->lowcore.words.access_id=S390_lowcore.per_access_id;
	}
	if(do_debugger_trap(regs,SIGTRAP))
	{
		/* I've seen this possibly a task structure being reused ? */
		printk("Spurious per exception detected\n");
		printk("switching off per tracing for this task.\n");
		show_regs(regs);
		/* Hopefully switching off per tracing will help us survive */
		regs->psw.mask &= ~PSW_PER_MASK;
	}
}