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

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 1994 - 1999 by Ralf Baechle
 * Copyright (C) 1995, 1996 Paul M. Antoine
 * Copyright (C) 1998 Ulf Carlsson
 * Copyright (C) 1999 Silicon Graphics, Inc.
 * Copyright (C) 2002  Maciej W. Rozycki
 */
#include <linux/config.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/spinlock.h>

#include <asm/bootinfo.h>
#include <asm/branch.h>
#include <asm/cpu.h>
#include <asm/module.h>
#include <asm/pgtable.h>
#include <asm/io.h>
#include <asm/ptrace.h>
#include <asm/watch.h>
#include <asm/system.h>
#include <asm/traps.h>
#include <asm/uaccess.h>
#include <asm/mmu_context.h>
#include <asm/cachectl.h>
#include <asm/types.h>

extern asmlinkage void __xtlb_mod(void);
extern asmlinkage void __xtlb_tlbl(void);
extern asmlinkage void __xtlb_tlbs(void);
extern asmlinkage void handle_adel(void);
extern asmlinkage void handle_ades(void);
extern asmlinkage void handle_ibe(void);
extern asmlinkage void handle_dbe(void);
extern asmlinkage void handle_sys(void);
extern asmlinkage void handle_bp(void);
extern asmlinkage void handle_ri(void);
extern asmlinkage void handle_cpu(void);
extern asmlinkage void handle_ov(void);
extern asmlinkage void handle_tr(void);
extern asmlinkage void handle_fpe(void);
extern asmlinkage void handle_watch(void);
extern asmlinkage void handle_mcheck(void);
extern asmlinkage void handle_reserved(void);

extern int fpu_emulator_cop1Handler(int xcptno, struct pt_regs *xcp,
	struct mips_fpu_soft_struct *ctx);

void fpu_emulator_init_fpu(void);

char watch_available = 0;
char dedicated_iv_available = 0;

int (*be_board_handler)(struct pt_regs *regs, int is_fixup);

int kstack_depth_to_print = 24;

/*
 * These constant is 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)

#define OPCODE 0xfc000000

/*
 * If the address is either in the .text section of the
 * kernel, or in the vmalloc'ed module regions, it *may*
 * be the address of a calling routine
 */

#ifdef CONFIG_MODULES

extern struct module *module_list;
extern struct module kernel_module;

static inline int kernel_text_address(long addr)
{
	extern char _stext, _etext;
	int retval = 0;
	struct module *mod;

	if (addr >= (long) &_stext && addr <= (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(long addr)
{
	extern char _stext, _etext;

	return (addr >= (long) &_stext && addr <= (long) &_etext);
}

#endif

/*
 * This routine abuses get_user()/put_user() to reference pointers
 * with at least a bit of error checking ...
 */
void show_stack(long *sp)
{
	int i;
	long stackdata;

	printk("Stack:");
	i = 0;
	while ((long) sp & (PAGE_SIZE - 1)) {
		if (i && ((i % 4) == 0))
			printk("\n      ");
		if (i > 40) {
			printk(" ...");
			break;
		}

		if (__get_user(stackdata, sp++)) {
			printk(" (Bad stack address)");
			break;
		}

		printk(" %016lx", stackdata);
		i++;
	}
	printk("\n");
}

void show_trace(long *sp)
{
	int i;
	long addr;

	printk("Call Trace:");
	i = 0;
	while ((long) sp & (PAGE_SIZE - 1)) {

		if (__get_user(addr, sp++)) {
			if (i && ((i % 3) == 0))
				printk("\n           ");
			printk(" (Bad stack address)\n");
			break;
		}

		/*
		 * 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)) {
			if (i && ((i % 3) == 0))
				printk("\n           ");
			if (i > 40) {
				printk(" ...");
				break;
			}

			printk(" [<%016lx>]", addr);
			i++;
		}
	}
	printk("\n");
}

void show_trace_task(struct task_struct *tsk)
{
	show_trace((long *)tsk->thread.reg29);
}


void show_code(unsigned int *pc)
{
	long i;

	printk("\nCode:");

	for(i = -3 ; i < 6 ; i++) {
		unsigned int insn;
		if (__get_user(insn, pc + i)) {
			printk(" (Bad address in epc)\n");
			break;
		}
		printk("%c%08x%c",(i?' ':'<'),insn,(i?' ':'>'));
	}
}

void show_regs(struct pt_regs *regs)
{
	printk("Cpu %d\n", smp_processor_id());
	/* Saved main processor registers. */
	printk("$0      : %016lx %016lx %016lx %016lx\n",
	       0UL, regs->regs[1], regs->regs[2], regs->regs[3]);
	printk("$4      : %016lx %016lx %016lx %016lx\n",
               regs->regs[4], regs->regs[5], regs->regs[6], regs->regs[7]);
	printk("$8      : %016lx %016lx %016lx %016lx\n",
	       regs->regs[8], regs->regs[9], regs->regs[10], regs->regs[11]);
	printk("$12     : %016lx %016lx %016lx %016lx\n",
               regs->regs[12], regs->regs[13], regs->regs[14], regs->regs[15]);
	printk("$16     : %016lx %016lx %016lx %016lx\n",
	       regs->regs[16], regs->regs[17], regs->regs[18], regs->regs[19]);
	printk("$20     : %016lx %016lx %016lx %016lx\n",
               regs->regs[20], regs->regs[21], regs->regs[22], regs->regs[23]);
	printk("$24     : %016lx %016lx\n",
	       regs->regs[24], regs->regs[25]);
	printk("$28     : %016lx %016lx %016lx %016lx\n",
	       regs->regs[28], regs->regs[29], regs->regs[30], regs->regs[31]);
	printk("Hi      : %016lx\n", regs->hi);
	printk("Lo      : %016lx\n", regs->lo);

	/* Saved cp0 registers. */
	printk("epc     : %016lx    %s\nbadvaddr: %016lx\n",
	       regs->cp0_epc, print_tainted(), regs->cp0_badvaddr);
	printk("Status  : %08x  [ ", (unsigned int) regs->cp0_status);
	if (regs->cp0_status & ST0_KX) printk("KX ");
	if (regs->cp0_status & ST0_SX) printk("SX ");
	if (regs->cp0_status & ST0_UX) printk("UX ");
	switch (regs->cp0_status & ST0_KSU) {
		case KSU_USER: printk("USER ");			break;
		case KSU_SUPERVISOR: printk("SUPERVISOR ");	break;
		case KSU_KERNEL: printk("KERNEL ");		break;
		default: printk("BAD_MODE ");			break;
	}
	if (regs->cp0_status & ST0_ERL) printk("ERL ");
	if (regs->cp0_status & ST0_EXL) printk("EXL ");
	if (regs->cp0_status & ST0_IE) printk("IE ");
	printk("]\n");

	printk("Cause   : %08x\n", (unsigned int) regs->cp0_cause);
}

void show_registers(struct pt_regs *regs)
{
	show_regs(regs);
	printk("Process %s (pid: %d, stackpage=%016lx)\n",
		current->comm, current->pid, (unsigned long) current);
	show_stack((long *) regs->regs[29]);
	show_trace((long *) regs->regs[29]);
	show_code((unsigned int *) regs->cp0_epc);
	printk("\n");
}

static spinlock_t die_lock = SPIN_LOCK_UNLOCKED;

void __die(const char * str, struct pt_regs * regs, const char * file,
	   const char * func, unsigned long line)
{
	console_verbose();
	spin_lock_irq(&die_lock);
	printk("%s", str);
	if (file && func)
		printk(" in %s:%s, line %ld", file, func, line);
	printk(":\n");
	show_registers(regs);
	spin_unlock_irq(&die_lock);
	do_exit(SIGSEGV);
}

void __die_if_kernel(const char * str, struct pt_regs * regs,
		     const char * file, const char * func, unsigned long line)
{
	if (!user_mode(regs))
		__die(str, regs, file, func, line);
}

extern const struct exception_table_entry __start___dbe_table[];
extern const struct exception_table_entry __stop___dbe_table[];

void __declare_dbe_table(void)
{
	__asm__ __volatile__(
	".section\t__dbe_table,\"a\"\n\t"
	".previous"
	);
}

static inline unsigned long
search_one_table(const struct exception_table_entry *first,
		 const struct exception_table_entry *last,
		 unsigned long value)
{
	const struct exception_table_entry *mid;
	long diff;

	while (first < last) {
		mid = (last - first) / 2 + first;
		diff = mid->insn - value;
		if (diff < 0)
			first = mid + 1;
		else
			last = mid;
	}
	return (first == last && first->insn == value) ? first->nextinsn : 0;
}

extern spinlock_t modlist_lock;

static inline unsigned long
search_dbe_table(unsigned long addr)
{
	unsigned long ret = 0;

#ifndef CONFIG_MODULES
	/* There is only the kernel to search.  */
	ret = search_one_table(__start___dbe_table, __stop___dbe_table-1, addr);
	return ret;
#else
	unsigned long flags;

	/* The kernel is the last "module" -- no need to treat it special.  */
	struct module *mp;
	struct archdata *ap;

	spin_lock_irqsave(&modlist_lock, flags);
	for (mp = module_list; mp != NULL; mp = mp->next) {
		if (!mod_member_present(mp, archdata_end) ||
        	    !mod_archdata_member_present(mp, struct archdata,
						 dbe_table_end))
			continue;
		ap = (struct archdata *)(mp->archdata_start);

		if (ap->dbe_table_start == NULL ||
		    !(mp->flags & (MOD_RUNNING | MOD_INITIALIZING)))
			continue;
		ret = search_one_table(ap->dbe_table_start,
				       ap->dbe_table_end - 1, addr);
		if (ret)
			break;
	}
	spin_unlock_irqrestore(&modlist_lock, flags);
	return ret;
#endif
}

asmlinkage void do_be(struct pt_regs *regs)
{
	unsigned long new_epc;
	unsigned long fixup = 0;
	int data = regs->cp0_cause & 4;
	int action = MIPS_BE_FATAL;

	if (data && !user_mode(regs))
		fixup = search_dbe_table(regs->cp0_epc);

	if (fixup)
		action = MIPS_BE_FIXUP;

	if (be_board_handler)
		action = be_board_handler(regs, fixup != 0);

	switch (action) {
	case MIPS_BE_DISCARD:
		return;
	case MIPS_BE_FIXUP:
		if (fixup) {
			new_epc = fixup_exception(dpf_reg, fixup,
						  regs->cp0_epc);
			regs->cp0_epc = new_epc;
			return;
		}
		break;
	default:
		break;
	}

	/*
	 * Assume it would be too dangerous to continue ...
	 */
	printk(KERN_ALERT "%s bus error, epc == %08lx, ra == %08lx\n",
	       data ? "Data" : "Instruction",
	       regs->cp0_epc, regs->regs[31]);
	die_if_kernel("Oops", regs);
	force_sig(SIGBUS, current);
}

asmlinkage void do_ov(struct pt_regs *regs)
{
	siginfo_t info;

	if (compute_return_epc(regs))
		return;

	info.si_code = FPE_INTOVF;
	info.si_signo = SIGFPE;
	info.si_errno = 0;
	info.si_addr = (void *)regs->cp0_epc;
	force_sig_info(SIGFPE, &info, current);
}

/*
 * XXX Delayed fp exceptions when doing a lazy ctx switch XXX
 */
asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
{
	if (fcr31 & FPU_CSR_UNI_X) {
		int sig;

		/*
	 	 * Unimplemented operation exception.  If we've got the full
		 * software emulator on-board, let's use it...
		 *
		 * Force FPU to dump state into task/thread context.  We're
		 * moving a lot of data here for what is probably a single
		 * instruction, but the alternative is to pre-decode the FP
		 * register operands before invoking the emulator, which seems
		 * a bit extreme for what should be an infrequent event.
		 */
		save_fp(current);