traps.c

linux-2.6.15.6

/*
 *  arch/s390/kernel/traps.c
 *
 *  S390 version
 *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
 *    Author(s): Martin Schwidefsky ([e-mail]),
 *               Denis Joseph Barrow ([e-mail],[e-mail]),
 *
 *  Derived from "arch/i386/kernel/traps.c"
 *    Copyright (C) 1991, 1992 Linus Torvalds
 */

/*
 * 'Traps.c' handles hardware traps and faults after we have saved some
 * state in 'asm.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/smp.h>
#include <linux/smp_lock.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/kallsyms.h>
#include <linux/reboot.h>

#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/atomic.h>
#include <asm/mathemu.h>
#include <asm/cpcmd.h>
#include <asm/s390_ext.h>
#include <asm/lowcore.h>
#include <asm/debug.h>

/* Called from entry.S only */
extern void handle_per_exception(struct pt_regs *regs);

typedef void pgm_check_handler_t(struct pt_regs *, long);
pgm_check_handler_t *pgm_check_table[128];

#ifdef CONFIG_SYSCTL
#ifdef CONFIG_PROCESS_DEBUG
int sysctl_userprocess_debug = 1;
#else
int sysctl_userprocess_debug = 0;
#endif
#endif

extern pgm_check_handler_t do_protection_exception;
extern pgm_check_handler_t do_dat_exception;
#ifdef CONFIG_PFAULT
extern int pfault_init(void);
extern void pfault_fini(void);
extern void pfault_interrupt(struct pt_regs *regs, __u16 error_code);
static ext_int_info_t ext_int_pfault;
#endif
extern pgm_check_handler_t do_monitor_call;

#define stack_pointer ({ void **sp; asm("la %0,0(15)" : "=&d" (sp)); sp; })

#ifndef CONFIG_ARCH_S390X
#define FOURLONG "%08lx %08lx %08lx %08lx\n"
static int kstack_depth_to_print = 12;
#else /* CONFIG_ARCH_S390X */
#define FOURLONG "%016lx %016lx %016lx %016lx\n"
static int kstack_depth_to_print = 20;
#endif /* CONFIG_ARCH_S390X */

/*
 * For show_trace we have tree different stack to consider:
 *   - the panic stack which is used if the kernel stack has overflown
 *   - the asynchronous interrupt stack (cpu related)
 *   - the synchronous kernel stack (process related)
 * The stack trace can start at any of the three stack and can potentially
 * touch all of them. The order is: panic stack, async stack, sync stack.
 */
static unsigned long
__show_trace(unsigned long sp, unsigned long low, unsigned long high)
{
	struct stack_frame *sf;
	struct pt_regs *regs;

	while (1) {
		sp = sp & PSW_ADDR_INSN;
		if (sp < low || sp > high - sizeof(*sf))
			return sp;
		sf = (struct stack_frame *) sp;
		printk("([<%016lx>] ", sf->gprs[8] & PSW_ADDR_INSN);
		print_symbol("%s)\n", sf->gprs[8] & PSW_ADDR_INSN);
		/* Follow the backchain. */
		while (1) {
			low = sp;
			sp = sf->back_chain & PSW_ADDR_INSN;
			if (!sp)
				break;
			if (sp <= low || sp > high - sizeof(*sf))
				return sp;
			sf = (struct stack_frame *) sp;
			printk(" [<%016lx>] ", sf->gprs[8] & PSW_ADDR_INSN);
			print_symbol("%s\n", sf->gprs[8] & PSW_ADDR_INSN);
		}
		/* Zero backchain detected, check for interrupt frame. */
		sp = (unsigned long) (sf + 1);
		if (sp <= low || sp > high - sizeof(*regs))
			return sp;
		regs = (struct pt_regs *) sp;
		printk(" [<%016lx>] ", regs->psw.addr & PSW_ADDR_INSN);
		print_symbol("%s\n", regs->psw.addr & PSW_ADDR_INSN);
		low = sp;
		sp = regs->gprs[15];
	}
}

void show_trace(struct task_struct *task, unsigned long * stack)
{
	register unsigned long __r15 asm ("15");
	unsigned long sp;

	sp = (unsigned long) stack;
	if (!sp)
		sp = task ? task->thread.ksp : __r15;
	printk("Call Trace:\n");
#ifdef CONFIG_CHECK_STACK
	sp = __show_trace(sp, S390_lowcore.panic_stack - 4096,
			  S390_lowcore.panic_stack);
#endif
	sp = __show_trace(sp, S390_lowcore.async_stack - ASYNC_SIZE,
			  S390_lowcore.async_stack);
	if (task)
		__show_trace(sp, (unsigned long) task->thread_info,
			     (unsigned long) task->thread_info + THREAD_SIZE);
	else
		__show_trace(sp, S390_lowcore.thread_info,
			     S390_lowcore.thread_info + THREAD_SIZE);
	printk("\n");
}

void show_stack(struct task_struct *task, unsigned long *sp)
{
	register unsigned long * __r15 asm ("15");
	unsigned long *stack;
	int i;

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

	if (!sp)
		sp = task ? (unsigned long *) task->thread.ksp : __r15;

	stack = sp;
	for (i = 0; i < kstack_depth_to_print; i++) {
		if (((addr_t) stack & (THREAD_SIZE-1)) == 0)
			break;
		if (i && ((i * sizeof (long) % 32) == 0))
			printk("\n       ");
		printk("%p ", (void *)*stack++);
	}
	printk("\n");
	show_trace(task, sp);
}

/*
 * The architecture-independent dump_stack generator
 */
void dump_stack(void)
{
	show_stack(0, 0);
}

EXPORT_SYMBOL(dump_stack);

void show_registers(struct pt_regs *regs)
{
	mm_segment_t old_fs;
	char *mode;
	int i;

	mode = (regs->psw.mask & PSW_MASK_PSTATE) ? "User" : "Krnl";
	printk("%s PSW : %p %p",
	       mode, (void *) regs->psw.mask,
	       (void *) regs->psw.addr);
	print_symbol(" (%s)\n", regs->psw.addr & PSW_ADDR_INSN);
	printk("%s GPRS: " FOURLONG, mode,
	       regs->gprs[0], regs->gprs[1], regs->gprs[2], regs->gprs[3]);
	printk("           " FOURLONG,
	       regs->gprs[4], regs->gprs[5], regs->gprs[6], regs->gprs[7]);
	printk("           " FOURLONG,
	       regs->gprs[8], regs->gprs[9], regs->gprs[10], regs->gprs[11]);
	printk("           " FOURLONG,
	       regs->gprs[12], regs->gprs[13], regs->gprs[14], regs->gprs[15]);

#if 0
	/* FIXME: this isn't needed any more but it changes the ksymoops
	 * input. To remove or not to remove ... */
	save_access_regs(regs->acrs);
	printk("%s ACRS: %08x %08x %08x %08x\n", mode,
	       regs->acrs[0], regs->acrs[1], regs->acrs[2], regs->acrs[3]);
	printk("           %08x %08x %08x %08x\n",
	       regs->acrs[4], regs->acrs[5], regs->acrs[6], regs->acrs[7]);
	printk("           %08x %08x %08x %08x\n",
	       regs->acrs[8], regs->acrs[9], regs->acrs[10], regs->acrs[11]);
	printk("           %08x %08x %08x %08x\n",
	       regs->acrs[12], regs->acrs[13], regs->acrs[14], regs->acrs[15]);
#endif

	/*
	 * Print the first 20 byte of the instruction stream at the
	 * time of the fault.
	 */
	old_fs = get_fs();
	if (regs->psw.mask & PSW_MASK_PSTATE)
		set_fs(USER_DS);
	else
		set_fs(KERNEL_DS);
	printk("%s Code: ", mode);
	for (i = 0; i < 20; i++) {
		unsigned char c;
		if (__get_user(c, (char __user *)(regs->psw.addr + i))) {
			printk(" Bad PSW.");
			break;
		}
		printk("%02x ", c);
	}
	set_fs(old_fs);

	printk("\n");
}	

/* This is called from fs/proc/array.c */
char *task_show_regs(struct task_struct *task, char *buffer)
{
	struct pt_regs *regs;

	regs = __KSTK_PTREGS(task);
	buffer += sprintf(buffer, "task: %p, ksp: %p\n",
		       task, (void *)task->thread.ksp);
	buffer += sprintf(buffer, "User PSW : %p %p\n",
		       (void *) regs->psw.mask, (void *)regs->psw.addr);

	buffer += sprintf(buffer, "User GPRS: " FOURLONG,
			  regs->gprs[0], regs->gprs[1],
			  regs->gprs[2], regs->gprs[3]);
	buffer += sprintf(buffer, "           " FOURLONG,
			  regs->gprs[4], regs->gprs[5],
			  regs->gprs[6], regs->gprs[7]);
	buffer += sprintf(buffer, "           " FOURLONG,
			  regs->gprs[8], regs->gprs[9],
			  regs->gprs[10], regs->gprs[11]);
	buffer += sprintf(buffer, "           " FOURLONG,
			  regs->gprs[12], regs->gprs[13],
			  regs->gprs[14], regs->gprs[15]);
	buffer += sprintf(buffer, "User ACRS: %08x %08x %08x %08x\n",
			  task->thread.acrs[0], task->thread.acrs[1],
			  task->thread.acrs[2], task->thread.acrs[3]);
	buffer += sprintf(buffer, "           %08x %08x %08x %08x\n",
			  task->thread.acrs[4], task->thread.acrs[5],
			  task->thread.acrs[6], task->thread.acrs[7]);
	buffer += sprintf(buffer, "           %08x %08x %08x %08x\n",
			  task->thread.acrs[8], task->thread.acrs[9],
			  task->thread.acrs[10], task->thread.acrs[11]);
	buffer += sprintf(buffer, "           %08x %08x %08x %08x\n",
			  task->thread.acrs[12], task->thread.acrs[13],
			  task->thread.acrs[14], task->thread.acrs[15]);
	return buffer;
}

DEFINE_SPINLOCK(die_lock);

void die(const char * str, struct pt_regs * regs, long err)
{
	static int die_counter;

	debug_stop_all();
	console_verbose();
	spin_lock_irq(&die_lock);
	bust_spinlocks(1);
	printk("%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
        show_regs(regs);
	bust_spinlocks(0);
        spin_unlock_irq(&die_lock);
	if (in_interrupt())
		panic("Fatal exception in interrupt");
	if (panic_on_oops)
		panic("Fatal exception: panic_on_oops");
        do_exit(SIGSEGV);
}

static void inline
report_user_fault(long interruption_code, struct pt_regs *regs)
{
#if defined(CONFIG_SYSCTL)
	if (!sysctl_userprocess_debug)
		return;
#endif
#if defined(CONFIG_SYSCTL) || defined(CONFIG_PROCESS_DEBUG)
	printk("User process fault: interruption code 0x%lX\n",
	       interruption_code);
	show_regs(regs);
#endif
}

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_MASK_PSTATE)
		local_irq_enable();

        if (regs->psw.mask & PSW_MASK_PSTATE) {
                struct task_struct *tsk = current;

                tsk->thread.trap_no = interruption_code & 0xffff;
		force_sig_info(signr, info, tsk);
		report_user_fault(interruption_code, regs);
        } else {
                const struct exception_table_entry *fixup;
                fixup = search_exception_tables(regs->psw.addr & PSW_ADDR_INSN);
                if (fixup)
                        regs->psw.addr = fixup->fixup | PSW_ADDR_AMODE;
                else
                        die(str, regs, interruption_code);
        }
}

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

void do_single_step(struct pt_regs *regs)
{
	if ((current->ptrace & PT_PTRACED) != 0)
		force_sig(SIGTRAP, current);
}

asmlinkage void
default_trap_handler(struct pt_regs * regs, long interruption_code)
{
        if (regs->psw.mask & PSW_MASK_PSTATE) {
		local_irq_enable();
		do_exit(SIGSEGV);
		report_user_fault(interruption_code, regs);
	} else
		die("Unknown program exception", regs, interruption_code);
}

#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); \