[S390] Improved oops output.

This patch adds two improvements to the oops output. First it adds an
additional line after the PSW which decodes the different fields of it.
Second a disassembler is added that decodes the instructions surrounding
the faulting PSW. The output of a test oops now looks like this:

kernel BUG at init/main.c:419
illegal operation: 0001 [#1]
CPU:    0    Not tainted
Process swapper (pid: 0, task: 0000000000464968, ksp: 00000000004be000)
Krnl PSW : 0700000180000000 00000000000120b6 (rest_init+0x36/0x38)
           R:0 T:1 IO:1 EX:1 Key:0 M:0 W:0 P:0 AS:0 CC:0 PM:0 EA:3
Krnl GPRS: 0000000000000003 00000000004ba017 0000000000000022 0000000000000001
           000000000003a5f6 0000000000000000 00000000004be6a8 0000000000000000
           0000000000000000 00000000004b8200 0000000000003a50 0000000000008000
           0000000000516368 000000000033d008 00000000000120b2 00000000004bdee0
Krnl Code: 00000000000120a6: e3e0f0980024       stg     %r14,152(%r15)
           00000000000120ac: c0e500014296       brasl   %r14,3a5d8
           00000000000120b2: a7f40001           brc     15,120b4
          >00000000000120b6: 0707               bcr     0,%r7
           00000000000120b8: eb7ff0500024       stmg    %r7,%r15,80(%r15)
           00000000000120be: c0d000195825       larl    %r13,33d108
           00000000000120c4: a7f13f00           tmll    %r15,16128
           00000000000120c8: a7840001           brc     8,120ca
Call Trace:
([<00000000000120b2>] rest_init+0x32/0x38)
 [<00000000004be614>] start_kernel+0x37c/0x410
 [<0000000000012020>] _ehead+0x20/0x80

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

1 files changed, 17 insertions, 38 deletions

diff --git a/arch/s390/kernel/traps.c b/arch/s390/kernel/traps.c
index f0e5a320e2ec..a6540940190b 100644
--- a/arch/s390/kernel/traps.c
+++ b/arch/s390/kernel/traps.c
@@ -188,18 +188,31 @@ void dump_stack(void)
 
 EXPORT_SYMBOL(dump_stack);
 
+static inline int mask_bits(struct pt_regs *regs, unsigned long bits)
+{
+        return (regs->psw.mask & bits) / ((~bits + 1) & bits);
+}
+
 void show_registers(struct pt_regs *regs)
 {
-        mm_segment_t old_fs;
         char *mode;
-        int i;
 
         mode = (regs->psw.mask & PSW_MASK_PSTATE) ? "User" : "Krnl";
         printk("%s PSW : %p %p",
                mode, (void *) regs->psw.mask,
                (void *) regs->psw.addr);
         print_symbol(" (%s)\n", regs->psw.addr & PSW_ADDR_INSN);
-        printk("%s GPRS: " FOURLONG, mode,
+        printk("           R:%x T:%x IO:%x EX:%x Key:%x M:%x W:%x "
+               "P:%x AS:%x CC:%x PM:%x", mask_bits(regs, PSW_MASK_PER),
+               mask_bits(regs, PSW_MASK_DAT), mask_bits(regs, PSW_MASK_IO),
+               mask_bits(regs, PSW_MASK_EXT), mask_bits(regs, PSW_MASK_KEY),
+               mask_bits(regs, PSW_MASK_MCHECK), mask_bits(regs, PSW_MASK_WAIT),
+               mask_bits(regs, PSW_MASK_PSTATE), mask_bits(regs, PSW_MASK_ASC),
+               mask_bits(regs, PSW_MASK_CC), mask_bits(regs, PSW_MASK_PM));
+#ifdef CONFIG_64BIT
+        printk(" EA:%x", mask_bits(regs, PSW_BASE_BITS));
+#endif
+        printk("\n%s GPRS: " FOURLONG, mode,
                regs->gprs[0], regs->gprs[1], regs->gprs[2], regs->gprs[3]);
         printk("           " FOURLONG,
                regs->gprs[4], regs->gprs[5], regs->gprs[6], regs->gprs[7]);
@@ -208,41 +221,7 @@ void show_registers(struct pt_regs *regs)
         printk("           " FOURLONG,
                regs->gprs[12], regs->gprs[13], regs->gprs[14], regs->gprs[15]);
 
-#if 0
-        /* FIXME: this isn't needed any more but it changes the ksymoops
-         * input. To remove or not to remove ... */
-        save_access_regs(regs->acrs);
-        printk("%s ACRS: %08x %08x %08x %08x\n", mode,
-               regs->acrs[0], regs->acrs[1], regs->acrs[2], regs->acrs[3]);
-        printk("           %08x %08x %08x %08x\n",
-               regs->acrs[4], regs->acrs[5], regs->acrs[6], regs->acrs[7]);
-        printk("           %08x %08x %08x %08x\n",
-               regs->acrs[8], regs->acrs[9], regs->acrs[10], regs->acrs[11]);
-        printk("           %08x %08x %08x %08x\n",
-               regs->acrs[12], regs->acrs[13], regs->acrs[14], regs->acrs[15]);
-#endif
-
-        /*
-         * Print the first 20 byte of the instruction stream at the
-         * time of the fault.
-         */
-        old_fs = get_fs();
-        if (regs->psw.mask & PSW_MASK_PSTATE)
-                set_fs(USER_DS);
-        else
-                set_fs(KERNEL_DS);
-        printk("%s Code: ", mode);
-        for (i = 0; i < 20; i++) {
-                unsigned char c;
-                if (__get_user(c, (char __user *)(regs->psw.addr + i))) {
-                        printk(" Bad PSW.");
-                        break;
-                }
-                printk("%02x ", c);
-        }
-        set_fs(old_fs);
-
-        printk("\n");
+        show_code(regs);
 }       
 
 /* This is called from fs/proc/array.c */