parisc: Report trap type as human readable string

When faulting on some trap, the kernel currently reports in dmesg:

 do_page_fault() command='perl' type=6 address=0xbe400403 in libcrypt-2.24.so[f9086000+9000]
 vm_start = 0x00922000, vm_end = 0x00aed000

With this change the trap type additionally gets reported as human readable
string which makes it simpler to recognize the type of problem:

 do_page_fault() command='perl' type=6 address=0xbe400403 in libcrypt-2.24.so[f9086000+9000]
 trap #6: Instruction TLB miss fault, vm_start = 0x00922000, vm_end = 0x00aed000

Signed-off-by: Helge Deller <deller@gmx.de>

1 files changed, 47 insertions, 1 deletions

diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c
index 163af2c31d76..47a6ca4c9e40 100644
--- a/arch/parisc/mm/fault.c
+++ b/arch/parisc/mm/fault.c
@@ -168,6 +168,43 @@ int fixup_exception(struct pt_regs *regs)
 }
 
 /*
+ * parisc hardware trap list
+ *
+ * Documented in section 3 "Addressing and Access Control" of the
+ * "PA-RISC 1.1 Architecture and Instruction Set Reference Manual"
+ * https://parisc.wiki.kernel.org/index.php/File:Pa11_acd.pdf
+ *
+ * For implementation see handle_interruption() in traps.c
+ */
+static const char * const trap_description[] = {
+        [1] "High-priority machine check (HPMC)",
+        [2] "Power failure interrupt",
+        [3] "Recovery counter trap",
+        [5] "Low-priority machine check",
+        [6] "Instruction TLB miss fault",
+        [7] "Instruction access rights / protection trap",
+        [8] "Illegal instruction trap",
+        [9] "Break instruction trap",
+        [10] "Privileged operation trap",
+        [11] "Privileged register trap",
+        [12] "Overflow trap",
+        [13] "Conditional trap",
+        [14] "FP Assist Exception trap",
+        [15] "Data TLB miss fault",
+        [16] "Non-access ITLB miss fault",
+        [17] "Non-access DTLB miss fault",
+        [18] "Data memory protection/unaligned access trap",
+        [19] "Data memory break trap",
+        [20] "TLB dirty bit trap",
+        [21] "Page reference trap",
+        [22] "Assist emulation trap",
+        [25] "Taken branch trap",
+        [26] "Data memory access rights trap",
+        [27] "Data memory protection ID trap",
+        [28] "Unaligned data reference trap",
+};
+
+/*
  * Print out info about fatal segfaults, if the show_unhandled_signals
  * sysctl is set:
  */
@@ -176,6 +213,8 @@ show_signal_msg(struct pt_regs *regs, unsigned long code,
                 unsigned long address, struct task_struct *tsk,
                 struct vm_area_struct *vma)
 {
+        const char *trap_name = NULL;
+
         if (!unhandled_signal(tsk, SIGSEGV))
                 return;
 
@@ -186,8 +225,15 @@ show_signal_msg(struct pt_regs *regs, unsigned long code,
         pr_warn("do_page_fault() command='%s' type=%lu address=0x%08lx",
             tsk->comm, code, address);
         print_vma_addr(KERN_CONT " in ", regs->iaoq[0]);
+
+        if (code < ARRAY_SIZE(trap_description))
+                trap_name = trap_description[code];
+        pr_warn(KERN_CONT " trap #%lu: %s%c", code,
+                trap_name ? trap_name : "unknown",
+                vma ? ',':'\n');
+
         if (vma)
-                pr_warn(" vm_start = 0x%08lx, vm_end = 0x%08lx\n",
+                pr_warn(KERN_CONT " vm_start = 0x%08lx, vm_end = 0x%08lx\n",
                                 vma->vm_start, vma->vm_end);
 
         show_regs(regs);