• Christian Borntraeger's avatar
    [S390] kernel: show last breaking-event-address on oops · 9e74a6b8
    Christian Borntraeger authored
    Newer s390 models have a breaking-event-address-recording register.
    Each time an instruction causes a break in the sequential instruction
    execution, the address is saved in that hardware register. On a program
    interrupt the address is copied to the lowcore address 272-279, which
    makes it software accessible.
    This patch changes the program check handler and the stack overflow
    checker to copy the value into the pt_regs argument.
    The oops output is enhanced to show the last known breaking address.
    It might give additional information if the stack trace is corrupted.
    The feature is only available on 64 bit.
    The new oops output looks like:
    Modules linked in: vmcp sunrpc qeth_l2 dm_mod qeth ccwgroup
    CPU: 2 Not tainted 2.6.24zlive-host #8
    Process modprobe (pid: 4788, task: 00000000bf3d8718, ksp: 00000000b2b0b8e0)
    Krnl PSW : 0704200180000000 000003e000020028 (vmcp_init+0x28/0xe4 [vmcp])
               R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:0 CC:2 PM:0 EA:3
    Krnl GPRS: 0000000004000002 000003e000020000 0000000000000000 0000000000000001
               000000000015734c ffffffffffffffff 000003e0000b3b00 0000000000000000
               000003e00007ca30 00000000b5bb5d40 00000000b5bb5800 000003e0000b3b00
               000003e0000a2000 00000000003ecf50 00000000b2b0bd50 00000000b2b0bcb0
    Krnl Code: 000003e000020018: c0c000040ff4       larl    %r12,3e0000a2000
               000003e00002001e: e3e0f0000024       stg     %r14,0(%r15)
               000003e000020024: a7f40001           brc     15,3e000020026
              >000003e000020028: e310c0100004       lg      %r1,16(%r12)
               000003e00002002e: c020000413dc       larl    %r2,3e0000a27e6
               000003e000020034: c0a00004aee6       larl    %r10,3e0000b5e00
               000003e00002003a: a7490001           lghi    %r4,1
               000003e00002003e: a75900f0           lghi    %r5,240
    Call Trace:
    ([<000000000014b300>] blocking_notifier_call_chain+0x2c/0x40)
     [<000000000015735c>] sys_init_module+0x19d8/0x1b08
     [<0000000000110afc>] sysc_noemu+0x10/0x16
     [<000002000011cda2>] 0x2000011cda2
    Last Breaking-Event-Address:
     [<000003e000020024>] vmcp_init+0x24/0xe4 [vmcp]
    Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
    Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
    Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
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