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>

diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c
index 163af2c..47a6ca4 100644 (file)
--- 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);