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Commit 3b7df342 authored by Heiko Carstens's avatar Heiko Carstens Committed by Martin Schwidefsky
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s390/mm: print control registers and page table walk on crash 



Print extra debugging information to the console if the kernel or a user
space process crashed (with user space debugging enabled):

- contents of control register 7 and 13
- failing address and translation exception identification
- page table walk for the failing address

Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent e7c46c66

arch/s390/mm/fault.c

+135 −5
Original line number Diff line number Diff line
@@ -126,6 +126,133 @@ static inline int user_space_fault(struct pt_regs *regs) 
	return 0;

}



static int bad_address(void *p)

{

	unsigned long dummy;



	return probe_kernel_address((unsigned long *)p, dummy);

}



#ifdef CONFIG_64BIT

static void dump_pagetable(unsigned long asce, unsigned long address)

{

	unsigned long *table = __va(asce & PAGE_MASK);



	pr_alert("AS:%016lx ", asce);

	switch (asce & _ASCE_TYPE_MASK) {

	case _ASCE_TYPE_REGION1:

		table = table + ((address >> 53) & 0x7ff);

		if (bad_address(table))

			goto bad;

		pr_cont("R1:%016lx ", *table);

		if (*table & _REGION_ENTRY_INVALID)

			goto out;

		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);

		/* fallthrough */

	case _ASCE_TYPE_REGION2:

		table = table + ((address >> 42) & 0x7ff);

		if (bad_address(table))

			goto bad;

		pr_cont("R2:%016lx ", *table);

		if (*table & _REGION_ENTRY_INVALID)

			goto out;

		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);

		/* fallthrough */

	case _ASCE_TYPE_REGION3:

		table = table + ((address >> 31) & 0x7ff);

		if (bad_address(table))

			goto bad;

		pr_cont("R3:%016lx ", *table);

		if (*table & (_REGION_ENTRY_INVALID | _REGION3_ENTRY_LARGE))

			goto out;

		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);

		/* fallthrough */

	case _ASCE_TYPE_SEGMENT:

		table = table + ((address >> 20) & 0x7ff);

		if (bad_address(table))

			goto bad;

		pr_cont(KERN_CONT "S:%016lx ", *table);

		if (*table & (_SEGMENT_ENTRY_INVALID | _SEGMENT_ENTRY_LARGE))

			goto out;

		table = (unsigned long *)(*table & _SEGMENT_ENTRY_ORIGIN);

	}

	table = table + ((address >> 12) & 0xff);

	if (bad_address(table))

		goto bad;

	pr_cont("P:%016lx ", *table);

out:

	pr_cont("\n");

	return;

bad:

	pr_cont("BAD\n");

}



#else /* CONFIG_64BIT */



static void dump_pagetable(unsigned long asce, unsigned long address)

{

	unsigned long *table = __va(asce & PAGE_MASK);



	pr_alert("AS:%08lx ", asce);

	table = table + ((address >> 20) & 0x7ff);

	if (bad_address(table))

		goto bad;

	pr_cont("S:%08lx ", *table);

	if (*table & _SEGMENT_ENTRY_INVALID)

		goto out;

	table = (unsigned long *)(*table & _SEGMENT_ENTRY_ORIGIN);

	table = table + ((address >> 12) & 0xff);

	if (bad_address(table))

		goto bad;

	pr_cont("P:%08lx ", *table);

out:

	pr_cont("\n");

	return;

bad:

	pr_cont("BAD\n");

}



#endif /* CONFIG_64BIT */



static void dump_fault_info(struct pt_regs *regs)

{

	unsigned long asce;



	pr_alert("Fault in ");

	switch (regs->int_parm_long & 3) {

	case 3:

		pr_cont("home space ");

		break;

	case 2:

		pr_cont("secondary space ");

		break;

	case 1:

		pr_cont("access register ");

		break;

	case 0:

		pr_cont("primary space ");

		break;

	}

	pr_cont("mode while using ");

	if (!user_space_fault(regs)) {

		asce = S390_lowcore.kernel_asce;

		pr_cont("kernel ");

	}

#ifdef CONFIG_PGSTE

	else if ((current->flags & PF_VCPU) && S390_lowcore.gmap) {

		struct gmap *gmap = (struct gmap *)S390_lowcore.gmap;

		asce = gmap->asce;

		pr_cont("gmap ");

	}

#endif

	else {

		asce = S390_lowcore.user_asce;

		pr_cont("user ");

	}

	pr_cont("ASCE.\n");

	dump_pagetable(asce, regs->int_parm_long & __FAIL_ADDR_MASK);

}



static inline void report_user_fault(struct pt_regs *regs, long signr)

{

	if ((task_pid_nr(current) > 1) && !show_unhandled_signals)
@@ -138,8 +265,9 @@ static inline void report_user_fault(struct pt_regs *regs, long signr) 
	       regs->int_code);

	print_vma_addr(KERN_CONT "in ", regs->psw.addr & PSW_ADDR_INSN);

	printk(KERN_CONT "\n");

	printk(KERN_ALERT "failing address: %lX\n",

	       regs->int_parm_long & __FAIL_ADDR_MASK);

	printk(KERN_ALERT "failing address: %016lx TEID: %016lx\n",

	       regs->int_parm_long & __FAIL_ADDR_MASK, regs->int_parm_long);

	dump_fault_info(regs);

	show_regs(regs);

}
@@ -177,11 +305,13 @@ static noinline void do_no_context(struct pt_regs *regs) 
	address = regs->int_parm_long & __FAIL_ADDR_MASK;

	if (!user_space_fault(regs))

		printk(KERN_ALERT "Unable to handle kernel pointer dereference"

		       " at virtual kernel address %p\n", (void *)address);

		       " in virtual kernel address space\n");

	else

		printk(KERN_ALERT "Unable to handle kernel paging request"

		       " at virtual user address %p\n", (void *)address);



		       " in virtual user address space\n");

	printk(KERN_ALERT "failing address: %016lx TEID: %016lx\n",

	       regs->int_parm_long & __FAIL_ADDR_MASK, regs->int_parm_long);

	dump_fault_info(regs);

	die(regs, "Oops");

	do_exit(SIGKILL);

}