traps.c

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/*
 *  linux/arch/x86-64/traps.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
 *
 *  Pentium III FXSR, SSE support
 *	Gareth Hughes <[e-mail]>, May 2000
 *
 *  $Id: traps.c,v 1.36 2002/03/24 11:09:10 ak Exp $
 */

/*
 * 'Traps.c' handles hardware traps and faults after we have saved some
 * state in 'entry.S'.
 */
#include <linux/config.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/module.h>

#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/atomic.h>
#include <asm/debugreg.h>
#include <asm/desc.h>
#include <asm/i387.h>
#include <asm/kdebug.h>

#include <asm/smp.h>
#include <asm/pgalloc.h>
#include <asm/pda.h>

#include <linux/irq.h>

asmlinkage int system_call(void);
asmlinkage int kernel_syscall(void);
extern void ia32_syscall(void);

char doublefault_stack[4*1024]; 
#ifndef CONFIG_SMP
char stackfault_stack[4*1024];
#endif

extern struct gate_struct idt_table[256]; 

asmlinkage void divide_error(void);
asmlinkage void debug(void);
asmlinkage void nmi(void);
asmlinkage void int3(void);
asmlinkage void overflow(void);
asmlinkage void bounds(void);
asmlinkage void invalid_op(void);
asmlinkage void device_not_available(void);
asmlinkage void double_fault(void);
asmlinkage void coprocessor_segment_overrun(void);
asmlinkage void invalid_TSS(void);
asmlinkage void segment_not_present(void);
asmlinkage void stack_segment(void);
asmlinkage void general_protection(void);
asmlinkage void page_fault(void);
asmlinkage void coprocessor_error(void);
asmlinkage void simd_coprocessor_error(void);
asmlinkage void reserved(void);
asmlinkage void alignment_check(void);
asmlinkage void machine_check(void);
asmlinkage void spurious_interrupt_bug(void);
asmlinkage void call_debug(void);

extern char iret_address[];

struct notifier_block *die_chain;

int kstack_depth_to_print = 10;

#ifdef CONFIG_KALLSYMS
#include <linux/kallsyms.h> 
int printk_address(unsigned long address)
{ 
	unsigned long dummy; 
	const char *modname, *secname, *symname;
	unsigned long symstart; 
	char *delim = ":"; 

	/* What a function call! */
	if (!kallsyms_address_to_symbol(address, 
					&modname, &dummy, &dummy, 
					&secname, &dummy, &dummy,
					&symname, &symstart, &dummy)) {
		return printk("[<%016lx>]", address);
	} 
	if (!strcmp(modname, "kernel"))
		modname = delim = ""; 		
        return printk("[%016lx%s%s%s%s%+ld]",
		      address,delim,modname,delim,symname,address-symstart); 
} 
#else
int printk_address(unsigned long address)
{ 
	return printk("[<%016lx>]", address);
} 
#endif


#ifdef CONFIG_MODULES

extern struct module *module_list;
extern struct module kernel_module;

static inline int kernel_text_address(unsigned long addr)
{
   int retval = 0;
   struct module *mod;

   if (addr >= (unsigned long) &_stext &&
       addr <= (unsigned long) &_etext)
       return 1;

   for (mod = module_list; mod != &kernel_module; mod = mod->next) {
       /* mod_bound tests for addr being inside the vmalloc'ed
        * module area. Of course it'd be better to test only
        * for the .text subset... */
       if (mod_bound(addr, 0, mod)) {
           retval = 1;
           break;
       }
   }

   return retval;
}

#else

static inline int kernel_text_address(unsigned long addr)
{
   return (addr >= (unsigned long) &_stext &&
       addr <= (unsigned long) &_etext);
}

#endif

/*
 * These constants are for searching for possible module text
 * segments. MODULE_RANGE is a guess of how much space is likely
 * to be vmalloced.
 */
#define MODULE_RANGE (8*1024*1024)

void show_trace(unsigned long *stack)
{
	unsigned long addr;
	unsigned long *irqstack, *irqstack_end;
	/* FIXME: should read the cpuid from the APIC; to still work with bogus %gs */
	const int cpu = smp_processor_id();
	int i;

	printk("\nCall Trace: ");

	irqstack_end = (unsigned long *) (cpu_pda[cpu].irqstackptr);
	irqstack = (unsigned long *) (cpu_pda[cpu].irqstackptr - IRQSTACKSIZE + 64);

	i = 1;
	if (stack >= irqstack && stack < irqstack_end) {
		unsigned long *tstack;
		while (stack < irqstack_end) {
			addr = *stack++;
			/*
			 * If the address is either in the text segment of the
			 * kernel, or in the region which contains vmalloc'ed
			 * memory, it *may* be the address of a calling
			 * routine; if so, print it so that someone tracing
			 * down the cause of the crash will be able to figure
			 * out the call path that was taken.
			 */
			 if (kernel_text_address(addr)) {  
				 i += printk_address(addr);
				 i += printk(" "); 
				 if (i > 50) { 
					printk("\n       ");
					 i = 0;
				 } 
			}
		} 
		stack = (unsigned long *) (irqstack_end[-1]);
		printk(" <EOI> ");
#if 1
		tstack = (unsigned long *)(current_thread_info()+1);
		if (stack < tstack || (char*)stack > (char*)tstack+THREAD_SIZE) 
			printk("\n" KERN_DEBUG 
		       "no stack at the end of irqstack; stack:%lx, curstack %lx\n",
			       stack, tstack); 
#endif			       
	} 

	

	while (((long) stack & (THREAD_SIZE-1)) != 0) {
		addr = *stack++;
		if (kernel_text_address(addr)) { 	 
			i += printk_address(addr);
			i += printk(" "); 
			if (i > 50) { 
				printk("\n       ");
					 i = 0;
			} 
		}
	}
	printk("\n");
}

void show_trace_task(struct task_struct *tsk)
{
	unsigned long rsp = tsk->thread.rsp;

	/* User space on another CPU? */
	if ((rsp ^ (unsigned long)tsk->thread_info) & (PAGE_MASK<<1))
		return;
	show_trace((unsigned long *)rsp);
}

void show_stack(unsigned long * rsp)
{
	unsigned long *stack;
	int i;
	const int cpu = smp_processor_id();
	unsigned long *irqstack_end = (unsigned long *) (cpu_pda[cpu].irqstackptr);
	unsigned long *irqstack = (unsigned long *) (cpu_pda[cpu].irqstackptr - IRQSTACKSIZE);    

	// debugging aid: "show_stack(NULL);" prints the
	// back trace for this cpu.

	if(rsp==NULL)
		rsp=(unsigned long*)&rsp;

	stack = rsp;
	for(i=0; i < kstack_depth_to_print; i++) {
		if (stack >= irqstack && stack <= irqstack_end) {
			if (stack == irqstack_end) {
				stack = (unsigned long *) (irqstack_end[-1]);
				printk(" <EOI> ");
			}
		} else {
		if (((long) stack & (THREAD_SIZE-1)) == 0)
			break;
		}
		if (i && ((i % 4) == 0))
			printk("\n       ");
		printk("%016lx ", *stack++);
	}
	show_trace((unsigned long *)rsp);
}

void show_registers(struct pt_regs *regs)
{
	int i;
	int in_kernel = 1;
	unsigned long rsp;
#ifdef CONFIG_SMP
	/* For SMP should get the APIC id here, just to protect against corrupted GS */ 
	const int cpu = smp_processor_id(); 
#else
	const int cpu = 0;
#endif	
	struct task_struct *cur = cpu_pda[cpu].pcurrent; 

	rsp = (unsigned long) (&regs->rsp);
	if (regs->rsp < TASK_SIZE) {
		in_kernel = 0;
		rsp = regs->rsp;
	}
	printk("CPU %d ", cpu);
	show_regs(regs);
	printk("Process %s (pid: %d, stackpage=%08lx)\n",
		cur->comm, cur->pid, 4096+(unsigned long)cur);

	/*
	 * When in-kernel, we also print out the stack and code at the
	 * time of the fault..
	 */
	if (in_kernel) {

		printk("Stack: ");
		show_stack((unsigned long*)rsp);

		printk("\nCode: ");
		if(regs->rip < PAGE_OFFSET)
			goto bad;

		for(i=0;i<20;i++)
		{
			unsigned char c;
			if(__get_user(c, &((unsigned char*)regs->rip)[i])) {
bad:
				printk(" Bad RIP value.");
				break;
			}
			printk("%02x ", c);
		}
	}
	printk("\n");
}	

void handle_BUG(struct pt_regs *regs)
{ 
	struct bug_frame f;
	char tmp;

	if (regs->cs & 3)
		return; 
	if (__copy_from_user(&f, (struct bug_frame *) regs->rip, 
			     sizeof(struct bug_frame)))
		return; 
	if ((unsigned long)f.filename < __PAGE_OFFSET || 
	    f.ud2[0] != 0x0f || f.ud2[1] != 0x0b) 
		return;
	if (__get_user(tmp, f.filename))
		f.filename = "unmapped filename"; 
	printk("Kernel BUG at %.50s:%d\n", f.filename, f.line); 	
} 

void out_of_line_bug(void)
{ 
	BUG(); 
} 

spinlock_t die_lock = SPIN_LOCK_UNLOCKED;
int die_owner = -1;

void die(const char * str, struct pt_regs * regs, long err)
{
	int cpu;
	struct die_args args = { regs, str, err };
	console_verbose();
	notifier_call_chain(&die_chain,  DIE_DIE, &args); 
	bust_spinlocks(1);
	handle_BUG(regs); 
	printk("%s: %04lx\n", str, err & 0xffff);
	cpu = smp_processor_id(); 
	/* racy, but better than risking deadlock. */ 
	__cli();
	if (!spin_trylock(&die_lock)) { 
		if (cpu == die_owner) 
			/* nested oops. should stop eventually */;
		else
			spin_lock(&die_lock); 
	}
	die_owner = cpu; 
	show_registers(regs);
	bust_spinlocks(0);
	spin_unlock_irq(&die_lock);
	notify_die(DIE_OOPS, (char *)str, regs, err);
	do_exit(SIGSEGV);
}

static inline void die_if_kernel(const char * str, struct pt_regs * regs, long err)
{
	if (!(regs->eflags & VM_MASK) && (regs->cs == __KERNEL_CS))
		die(str, regs, err);
}

static inline unsigned long get_cr2(void)
{
	unsigned long address;

	/* get the address */
	__asm__("movq %%cr2,%0":"=r" (address));
	return address;
}

static void do_trap(int trapnr, int signr, char *str, 
			   struct pt_regs * regs, long error_code, siginfo_t *info)
{
	if ((regs->cs & 3)  != 0) { 
		struct task_struct *tsk = current;

		if (trapnr != 3)
			printk("%s[%d] trap %s at rip:%lx rsp:%lx err:%lx\n",
		       tsk->comm, tsk->pid, str, regs->rip, regs->rsp, error_code);

		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;