traps.c

这个linux源代码是很全面的~基本完整了~使用c编译的~由于时间问题我没有亲自测试~但就算用来做参考资料也是非常好的

#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 *)siaddr; \
	do_trap(trapnr, signr, str, regs, error_code, &info); \
}

DO_ERROR_INFO( 0, SIGFPE,  "divide error", divide_error, FPE_INTDIV, regs->rip)
DO_ERROR( 4, SIGSEGV, "overflow", overflow)
DO_ERROR( 5, SIGSEGV, "bounds", bounds)
DO_ERROR_INFO( 6, SIGILL,  "invalid operand", invalid_op, ILL_ILLOPN, regs->rip)
DO_ERROR( 7, SIGSEGV, "device not available", device_not_available)
DO_ERROR( 8, SIGSEGV, "double fault", double_fault)
DO_ERROR( 9, SIGFPE,  "coprocessor segment overrun", coprocessor_segment_overrun)
DO_ERROR(10, SIGSEGV, "invalid TSS", invalid_TSS)
DO_ERROR(11, SIGBUS,  "segment not present", segment_not_present)
DO_ERROR(12, SIGBUS,  "stack segment", stack_segment)
DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, get_cr2())
DO_ERROR(18, SIGSEGV, "reserved", reserved)

asmlinkage void do_int3(struct pt_regs * regs, long error_code)
{
	if (notify_die(DIE_INT3, "int3", regs, error_code) == NOTIFY_BAD)
		return;
	do_trap(3, SIGTRAP, "int3", regs, error_code, NULL);
}

extern void dump_pagetable(unsigned long);

asmlinkage void do_general_protection(struct pt_regs * regs, long error_code)
{
#ifdef CONFIG_CHECKING
	{ 
		unsigned long gs; 
		struct x8664_pda *pda = cpu_pda + stack_smp_processor_id(); 
		rdmsrl(MSR_GS_BASE, gs); 
		if (gs != (unsigned long)pda) { 
			wrmsrl(MSR_GS_BASE, pda); 
			printk("general protection handler: wrong gs %lx expected %p\n", gs, pda);
		}
	}
#endif

	if (regs->cs & 3) { 		
		current->thread.error_code = error_code;
		current->thread.trap_no = 13;
		if (exception_trace)
			printk("%s[%d] general protection rip:%lx rsp:%lx error:%lx\n",
			       current->comm, current->pid,
			       regs->rip,regs->rsp,error_code); 
		force_sig(SIGSEGV, current);
		return;
	} 

	/* kernel gp */
	{
		unsigned long fixup;
		fixup = search_exception_table(regs->rip);
		if (fixup) {
			extern int exception_trace; 
			if (exception_trace)
				printk(KERN_ERR
			       "%s: fixed kernel gp exception at %lx err:%ld\n",
				       current->comm, regs->rip, error_code);

			regs->rip = fixup;
			return;
		}
		die("general protection fault", regs, error_code);
	}
}

static void mem_parity_error(unsigned char reason, struct pt_regs * regs)
{
	printk("Uhhuh. NMI received. Dazed and confused, but trying to continue\n");
	printk("You probably have a hardware problem with your RAM chips\n");

	/* Clear and disable the memory parity error line. */
	reason = (reason & 0xf) | 4;
	outb(reason, 0x61);
}

static void io_check_error(unsigned char reason, struct pt_regs * regs)
{
	printk("NMI: IOCK error (debug interrupt?)\n");
	show_registers(regs);

	/* Re-enable the IOCK line, wait for a few seconds */
	reason = (reason & 0xf) | 8;
	outb(reason, 0x61);
	mdelay(2000);
	reason &= ~8;
	outb(reason, 0x61);
}

static void unknown_nmi_error(unsigned char reason, struct pt_regs * regs)
{
	printk("Uhhuh. NMI received for unknown reason %02x on CPU %d.\n",
		reason, smp_processor_id());
	printk("Dazed and confused, but trying to continue\n");
	printk("Do you have a strange power saving mode enabled?\n");
}

static void default_do_nmi(struct pt_regs * regs)
{
	unsigned char reason = inb(0x61);
	
	if (!(reason & 0xc0)) {
#if CONFIG_X86_LOCAL_APIC
		/*
		 * Ok, so this is none of the documented NMI sources,
		 * so it must be the NMI watchdog.
		 */
		if (nmi_watchdog) {
			nmi_watchdog_tick(regs);
			return;
		}
#endif
		if (notify_die(DIE_NMI, "nmi", regs, reason) == NOTIFY_BAD)
			return;
		unknown_nmi_error(reason, regs);
		return;
	}
	if (notify_die(DIE_NMI, "nmi", regs, reason) == NOTIFY_BAD)
		return; 
	if (reason & 0x80)
		mem_parity_error(reason, regs);
	if (reason & 0x40)
		io_check_error(reason, regs);

	/*
	 * Reassert NMI in case it became active meanwhile
	 * as it's edge-triggered.
	 */
	outb(0x8f, 0x70);
	inb(0x71);		/* dummy */
	outb(0x0f, 0x70);
	inb(0x71);		/* dummy */
}

static int dummy_nmi_callback(struct pt_regs * regs, int cpu)
{
	return 0;
}
 
static nmi_callback_t nmi_callback = dummy_nmi_callback;
 
asmlinkage void do_nmi(struct pt_regs * regs, long error_code)
{
	int cpu = smp_processor_id();

	++nmi_count(cpu);

	if (!nmi_callback(regs, cpu))
		default_do_nmi(regs);
}

void set_nmi_callback(nmi_callback_t callback)
{
	nmi_callback = callback;
}

void unset_nmi_callback(void)
{
	nmi_callback = dummy_nmi_callback;
}


asmlinkage void do_debug(struct pt_regs * regs, long error_code)
{
	unsigned long condition;
	struct task_struct *tsk = current;
	siginfo_t info;

#ifdef CONFIG_CHECKING
	{ 
		unsigned long gs; 
		struct x8664_pda *pda = cpu_pda + stack_smp_processor_id(); 
		rdmsrl(MSR_GS_BASE, gs); 
		if (gs != (unsigned long)pda) { 
			wrmsrl(MSR_GS_BASE, pda); 
			printk("debug handler: wrong gs %lx expected %p\n", gs, pda);
		}
	}
#endif

	asm("movq %%db6,%0" : "=r" (condition));

	if (notify_die(DIE_DEBUG, "debug", regs, error_code) == NOTIFY_BAD)
		return; 

	/* Mask out spurious debug traps due to lazy DR7 setting */
	if (condition & (DR_TRAP0|DR_TRAP1|DR_TRAP2|DR_TRAP3)) {
		if (!tsk->thread.debugreg[7]) { 
			goto clear_dr7;
		}
	}

	tsk->thread.debugreg[6] = condition;

	/* Mask out spurious TF errors due to lazy TF clearing */
	if (condition & DR_STEP) {
		/*
		 * The TF error should be masked out only if the current
		 * process is not traced and if the TRAP flag has been set
		 * previously by a tracing process (condition detected by
		 * the PT_DTRACE flag); remember that the i386 TRAP flag
		 * can be modified by the process itself in user mode,
		 * allowing programs to debug themselves without the ptrace()
		 * interface.
		 */
                if ((regs->cs & 3) == 0)
                       goto clear_TF;
		if ((tsk->ptrace & (PT_DTRACE|PT_PTRACED)) == PT_DTRACE)
			goto clear_TF;
	}

	/* Ok, finally something we can handle */
	tsk->thread.trap_no = 1;
	tsk->thread.error_code = error_code;
	info.si_signo = SIGTRAP;
	info.si_errno = 0;
	info.si_code = TRAP_BRKPT;
	info.si_addr = ((regs->cs & 3) == 0) ? (void *)tsk->thread.rip : 
	                                        (void *)regs->rip;
	force_sig_info(SIGTRAP, &info, tsk);	
clear_dr7:
	asm("movq %0,%%db7"::"r"(0UL));
	return;

clear_TF:
	regs->eflags &= ~TF_MASK;
	return;
}

/*
 * Note that we play around with the 'TS' bit in an attempt to get
 * the correct behaviour even in the presence of the asynchronous
 * IRQ13 behaviour
 */
void math_error(void *rip)
{
	struct task_struct * task;
	siginfo_t info;
	unsigned short cwd, swd;

	/*
	 * Save the info for the exception handler and clear the error.
	 */
	task = current;
	save_init_fpu(task);
	task->thread.trap_no = 16;
	task->thread.error_code = 0;
	info.si_signo = SIGFPE;
	info.si_errno = 0;
	info.si_code = __SI_FAULT;
	info.si_addr = rip;
	/*
	 * (~cwd & swd) will mask out exceptions that are not set to unmasked
	 * status.  0x3f is the exception bits in these regs, 0x200 is the
	 * C1 reg you need in case of a stack fault, 0x040 is the stack
	 * fault bit.  We should only be taking one exception at a time,
	 * so if this combination doesn't produce any single exception,
	 * then we have a bad program that isn't syncronizing its FPU usage
	 * and it will suffer the consequences since we won't be able to
	 * fully reproduce the context of the exception
	 */
	cwd = get_fpu_cwd(task);
	swd = get_fpu_swd(task);
	switch (((~cwd) & swd & 0x3f) | (swd & 0x240)) {
		case 0x000:
		default:
			break;
		case 0x001: /* Invalid Op */
		case 0x041: /* Stack Fault */
		case 0x241: /* Stack Fault | Direction */
			info.si_code = FPE_FLTINV;
			break;
		case 0x002: /* Denormalize */
		case 0x010: /* Underflow */
			info.si_code = FPE_FLTUND;
			break;
		case 0x004: /* Zero Divide */
			info.si_code = FPE_FLTDIV;
			break;
		case 0x008: /* Overflow */
			info.si_code = FPE_FLTOVF;
			break;
		case 0x020: /* Precision */
			info.si_code = FPE_FLTRES;
			break;
	}
	force_sig_info(SIGFPE, &info, task);
}

asmlinkage void do_coprocessor_error(struct pt_regs * regs, long error_code)
{
	math_error((void *)regs->rip);
}

asmlinkage void bad_intr(void)
{
	printk("bad interrupt"); 
}

static inline void simd_math_error(void *rip)
{
	struct task_struct * task;
	siginfo_t info;
	unsigned short mxcsr;

	/*
	 * Save the info for the exception handler and clear the error.
	 */
	task = current;
	save_init_fpu(task);
	task->thread.trap_no = 19;
	task->thread.error_code = 0;
	info.si_signo = SIGFPE;
	info.si_errno = 0;
	info.si_code = __SI_FAULT;
	info.si_addr = rip;
	/*
	 * The SIMD FPU exceptions are handled a little differently, as there
	 * is only a single status/control register.  Thus, to determine which
	 * unmasked exception was caught we must mask the exception mask bits
	 * at 0x1f80, and then use these to mask the exception bits at 0x3f.
	 */
	mxcsr = get_fpu_mxcsr(task);
	switch (~((mxcsr & 0x1f80) >> 7) & (mxcsr & 0x3f)) {
		case 0x000:
		default:
			break;
		case 0x001: /* Invalid Op */
			info.si_code = FPE_FLTINV;
			break;
		case 0x002: /* Denormalize */
		case 0x010: /* Underflow */
			info.si_code = FPE_FLTUND;
			break;
		case 0x004: /* Zero Divide */
			info.si_code = FPE_FLTDIV;
			break;
		case 0x008: /* Overflow */
			info.si_code = FPE_FLTOVF;
			break;
		case 0x020: /* Precision */
			info.si_code = FPE_FLTRES;
			break;
	}
	force_sig_info(SIGFPE, &info, task);
}

asmlinkage void do_simd_coprocessor_error(struct pt_regs * regs,
					  long error_code)
{
	simd_math_error((void *)regs->rip);
}

asmlinkage void do_spurious_interrupt_bug(struct pt_regs * regs)
{
}

/*
 *  'math_state_restore()' saves the current math information in the
 * old math state array, and gets the new ones from the current task
 *
 * Careful.. There are problems with IBM-designed IRQ13 behaviour.
 * Don't touch unless you *really* know how it works.
 */
asmlinkage void math_state_restore(void)
{
	struct task_struct *me = current;
	clts();			/* Allow maths ops (or we recurse) */

	if (!me->used_math)
		init_fpu();        
	restore_fpu_checking(&me->thread.i387.fxsave);
	me->flags |= PF_USEDFPU;	/* So we fxsave on switch_to() */
}

asmlinkage void math_emulate(void)
{
	BUG();
}

void do_call_debug(struct pt_regs *regs) 
{ 
	notify_die(DIE_CALL, "debug call", regs, 0); 
} 

#ifndef CONFIG_MCE
void do_machine_check(struct pt_regs *regs)
{ 
	printk("Machine check ignored\n");
} 
#endif

void __init trap_init(void)
{
	set_intr_gate(0,&divide_error);
	set_intr_gate(1,&debug);
	set_intr_gate_ist(2,&nmi,NMI_STACK);
	set_system_gate(3,&int3);	/* int3-5 can be called from all */
	set_system_gate(4,&overflow);
	set_system_gate(5,&bounds);
	set_intr_gate(6,&invalid_op);
	set_intr_gate(7,&device_not_available);
	set_intr_gate_ist(8,&double_fault, DOUBLEFAULT_STACK);
	set_intr_gate(9,&coprocessor_segment_overrun);
	set_intr_gate(10,&invalid_TSS);
	set_intr_gate(11,&segment_not_present);
	set_intr_gate_ist(12,&stack_segment,STACKFAULT_STACK);
	set_intr_gate(13,&general_protection);
	set_intr_gate(14,&page_fault);
	set_intr_gate(15,&spurious_interrupt_bug);
	set_intr_gate(16,&coprocessor_error);
	set_intr_gate(17,&alignment_check);
	set_intr_gate(18,&machine_check); 
	set_intr_gate(19,&simd_coprocessor_error);

#ifdef CONFIG_IA32_EMULATION
	set_intr_gate(IA32_SYSCALL_VECTOR, ia32_syscall);
#endif

	set_intr_gate(KDB_VECTOR, call_debug);
       
	notify_die(DIE_TRAPINIT, "traps initialized", 0, 0); 
	
	/*
	 * Should be a barrier for any external CPU state.
	 */
	cpu_init();
}