traps.c

Linux内核源代码 为压缩文件 是<<Linux内核>>一书中的源代码

/*
 * 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
 * Modified for R3000 by Paul M. Antoine, 1995, 1996
 * Complete output from die() by Ulf Carlsson, 1998
 * Copyright (C) 1999 Silicon Graphics, Inc.
 */
#include <linux/config.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/spinlock.h>

#include <asm/branch.h>
#include <asm/cachectl.h>
#include <asm/jazz.h>
#include <asm/pgtable.h>
#include <asm/io.h>
#include <asm/bootinfo.h>
#include <asm/watch.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/mmu_context.h>

/*
 * Machine specific interrupt handlers
 */
extern asmlinkage void acer_pica_61_handle_int(void);
extern asmlinkage void decstation_handle_int(void);
extern asmlinkage void deskstation_rpc44_handle_int(void);
extern asmlinkage void deskstation_tyne_handle_int(void);
extern asmlinkage void mips_magnum_4000_handle_int(void);

extern asmlinkage void handle_mod(void);
extern asmlinkage void handle_tlbl(void);
extern asmlinkage void handle_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_reserved(void);

static char *cpu_names[] = CPU_NAMES;

char watch_available = 0;
char dedicated_iv_available = 0;
char vce_available = 0;

void (*ibe_board_handler)(struct pt_regs *regs);
void (*dbe_board_handler)(struct pt_regs *regs);

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)

#if !defined(CONFIG_CPU_HAS_LLSC)
/*
 * This stuff is needed for the userland ll-sc emulation for R2300
 */
void simulate_ll(struct pt_regs *regs, unsigned int opcode);
void simulate_sc(struct pt_regs *regs, unsigned int opcode);

#define OPCODE 0xfc000000
#define BASE   0x03e00000
#define RT     0x001f0000
#define OFFSET 0x0000ffff
#define LL     0xc0000000
#define SC     0xd0000000

#define DEBUG_LLSC
#endif

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

	stack = sp;
	i = 0;

	printk("Stack:");
	while ((unsigned long) stack & (PAGE_SIZE - 1)) {
		unsigned long stackdata;

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

		printk(" %08lx", stackdata);

		if (++i > 40) {
			printk(" ...");
			break;
		}

		if (i % 8 == 0)
			printk("\n      ");
	}
}

void show_trace(unsigned int *sp)
{
	int i;
	unsigned int *stack;
	unsigned long kernel_start, kernel_end;
	unsigned long module_start, module_end;
	extern char _stext, _etext;

	stack = sp;
	i = 0;

	kernel_start = (unsigned long) &_stext;
	kernel_end = (unsigned long) &_etext;
	module_start = VMALLOC_START;
	module_end = module_start + MODULE_RANGE;

	printk("\nCall Trace:");

	while ((unsigned long) stack & (PAGE_SIZE -1)) {
		unsigned long addr;

		if (__get_user(addr, stack++)) {
			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 ((addr >= kernel_start && addr < kernel_end) ||
		    (addr >= module_start && addr < module_end)) { 

			printk(" [<%08lx>]", addr);
			if (++i > 40) {
				printk(" ...");
				break;
			}
		}
	}
}

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

	printk("\nCode:");

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

spinlock_t die_lock;

extern void __die(const char * str, struct pt_regs * regs, const char *where,
                  unsigned long line)
{
	console_verbose();
	spin_lock_irq(&die_lock);
	printk("%s", str);
	if (where)
		printk(" in %s, line %ld", where, line);
	printk(":\n");
	show_regs(regs);
	printk("Process %s (pid: %d, stackpage=%08lx)\n",
		current->comm, current->pid, (unsigned long) current);
	show_stack((unsigned int *) regs->regs[29]);
	show_trace((unsigned int *) regs->regs[29]);
	show_code((unsigned int *) regs->cp0_epc);
	printk("\n");
while(1);
	spin_unlock_irq(&die_lock);
	do_exit(SIGSEGV);
}

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

#define search_dbe_table(addr)	\
	search_one_table(__start___dbe_table, __stop___dbe_table - 1, (addr))

static void default_be_board_handler(struct pt_regs *regs)
{
	unsigned long new_epc;
	unsigned long fixup = search_dbe_table(regs->cp0_epc);

	if (fixup) {
		new_epc = fixup_exception(dpf_reg, fixup, regs->cp0_epc);
		regs->cp0_epc = new_epc;
		return;
	}

	/*
	 * Assume it would be too dangerous to continue ...
	 */
/* XXX */
printk("Got Bus Error at %08x\n", (unsigned int)regs->cp0_epc);
show_regs(regs); while(1);
	force_sig(SIGBUS, current);
}

void do_ibe(struct pt_regs *regs)
{
	ibe_board_handler(regs);
}

void do_dbe(struct pt_regs *regs)
{
	dbe_board_handler(regs);
}

void do_ov(struct pt_regs *regs)
{
	if (compute_return_epc(regs))
		return;
	force_sig(SIGFPE, current);
}

#ifdef CONFIG_MIPS_FPE_MODULE
static void (*fpe_handler)(struct pt_regs *regs, unsigned int fcr31);

/*
 * Register_fpe/unregister_fpe are for debugging purposes only.  To make
 * this hack work a bit better there is no error checking.
 */
int register_fpe(void (*handler)(struct pt_regs *regs, unsigned int fcr31))
{
	fpe_handler = handler;
	return 0;
}

int unregister_fpe(void (*handler)(struct pt_regs *regs, unsigned int fcr31))
{
	fpe_handler = NULL;
	return 0;
}
#endif

/*
 * XXX Delayed fp exceptions when doing a lazy ctx switch XXX
 */
void do_fpe(struct pt_regs *regs, unsigned long fcr31)
{
	unsigned long pc;
	unsigned int insn;
	extern void simfp(unsigned int);

#ifdef CONFIG_MIPS_FPE_MODULE
	if (fpe_handler != NULL) {
		fpe_handler(regs, fcr31);
		return;
	}
#endif
	if (fcr31 & 0x20000) {
		/* Retry instruction with flush to zero ...  */
		if (!(fcr31 & (1<<24))) {
			printk("Setting flush to zero for %s.\n",
			       current->comm);
			fcr31 &= ~0x20000;
			fcr31 |= (1<<24);
			__asm__ __volatile__(
				"ctc1\t%0,$31"
				: /* No outputs */
				: "r" (fcr31));
			return;
		}
		pc = regs->cp0_epc + ((regs->cp0_cause & CAUSEF_BD) ? 4 : 0);
		if (get_user(insn, (unsigned int *)pc)) {
			/* XXX Can this happen?  */
			force_sig(SIGSEGV, current);
		}

		printk(KERN_DEBUG "Unimplemented exception for insn %08x at 0x%08lx in %s.\n",
		       insn, regs->cp0_epc, current->comm);
		simfp(insn);
	}

	if (compute_return_epc(regs))
		return;
	//force_sig(SIGFPE, current);
	printk(KERN_DEBUG "Should send SIGFPE to %s\n", current->comm);
}

static inline int get_insn_opcode(struct pt_regs *regs, unsigned int *opcode)
{
	unsigned int *epc;

	epc = (unsigned int *) (unsigned long) regs->cp0_epc;
	if (regs->cp0_cause & CAUSEF_BD)
		epc += 4;

	if (verify_area(VERIFY_READ, epc, 4)) {
		force_sig(SIGSEGV, current);
		return 1;
	}
	*opcode = *epc;

	return 0;
}

void do_bp(struct pt_regs *regs)
{
	unsigned int opcode, bcode;

	/*
	 * There is the ancient bug in the MIPS assemblers that the break
	 * code starts left to bit 16 instead to bit 6 in the opcode.
	 * Gas is bug-compatible ...
	 */
	if (get_insn_opcode(regs, &opcode))
		return;
	bcode = ((opcode >> 16) & ((1 << 20) - 1));

	/*
	 * (A short test says that IRIX 5.3 sends SIGTRAP for all break