arch/tile: add descriptive text if the kernel reports a bad trap

If the kernel unexpectedly takes a bad trap, it's convenient to
have it report the type of trap as part of the error.  This gives
customers a bit more context before they call up customer support.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

diff --git a/arch/tile/kernel/traps.c b/arch/tile/kernel/traps.c
index 73cff814ac57252065ca8086185f2fc7bb87c012..5b19a23c890801ef4f577228e083518d09302a58 100644 (file)
--- a/arch/tile/kernel/traps.c
+++ b/arch/tile/kernel/traps.c
@@ -195,6 +195,25 @@ static int special_ill(bundle_bits bundle, int *sigp, int *codep)
        return 1;
 }
 
+static const char *const int_name[] = {
+       [INT_MEM_ERROR] = "Memory error",
+       [INT_ILL] = "Illegal instruction",
+       [INT_GPV] = "General protection violation",
+       [INT_UDN_ACCESS] = "UDN access",
+       [INT_IDN_ACCESS] = "IDN access",
+#if CHIP_HAS_SN()
+       [INT_SN_ACCESS] = "SN access",
+#endif
+       [INT_SWINT_3] = "Software interrupt 3",
+       [INT_SWINT_2] = "Software interrupt 2",
+       [INT_SWINT_0] = "Software interrupt 0",
+       [INT_UNALIGN_DATA] = "Unaligned data",
+       [INT_DOUBLE_FAULT] = "Double fault",
+#ifdef __tilegx__
+       [INT_ILL_TRANS] = "Illegal virtual address",
+#endif
+};
+
 void __kprobes do_trap(struct pt_regs *regs, int fault_num,
                       unsigned long reason)
 {
@@ -211,10 +230,17 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num,
         * current process and hope for the best.
         */
        if (!user_mode(regs)) {
+               const char *name;
                if (fixup_exception(regs))  /* only UNALIGN_DATA in practice */
                        return;
-               pr_alert("Kernel took bad trap %d at PC %#lx\n",
-                      fault_num, regs->pc);
+               if (fault_num >= 0 &&
+                   fault_num < sizeof(int_name)/sizeof(int_name[0]) &&
+                   int_name[fault_num] != NULL)
+                       name = int_name[fault_num];
+               else
+                       name = "Unknown interrupt";
+               pr_alert("Kernel took bad trap %d (%s) at PC %#lx\n",
+                        fault_num, name, regs->pc);
                if (fault_num == INT_GPV)
                        pr_alert("GPV_REASON is %#lx\n", reason);
                show_regs(regs);