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: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index 19f623f..2f51a99 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -126,6 +126,133 @@
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 @@
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 @@
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);
}