From: rlarndt@austin.ibm.com (Richard L. Arndt)
Subject: Item #232: Halt-MCLogout
Date: Mon, 06 Feb 95 16:32:10 -0600

P1275 Open Firmware Working Group Proposal -- Proposal #232 Ver <Auth-Vers#>

Title:          Halt-MCLogout

Author:         R. L. Arndt rlarndt@austin.ibm.com

Date:           6 Feb 95

Ed/Tech:        Technical

Synopsis:       Add mandatory support of the halt string "machine-check-logout"

Doc & Version:  PowerPC processor binding -- dated: 941006

Problem:        Need mechanisms for the firmware to log out machine dependent
                hardware error status registers.

Proposal:

The firmware shall support halt string "machine-check-logout" in the
following manner.
Function:
 1. The firmware shall analyze any information which may exist in platform
dependent registers to determine the nature of the machine check and
record its findings in the system dependent error logout area.
 2. If the system supports machine check recovery, the firmware returns to
the caller (see System State at return below).  If the system does not
support machine check recovery, or can not do so in this case, the
firmware automatically executes a reboot.

System State at call:
 Memory:
        The ram image outside of that reserved for the Halt procedure is
        reserved for operating system use and shall not be modified by the
        Halt procedure.
 Master processor:
        As specified for other halt call-back functions.
        |%r3 | -halt argument-> | 1st pointer | --> machine-check-logout[0]
 Slave Processors:
        In an SMP system, the state of the other processors is undefined.
 IO Sub-system:
        The state of the IO sub-system is undefined.
 Interrupt Sub-system:
        The processor's MSR EE=0 prior to calling the Halt procedure.

System State at return:
 Memory:
        The state of the memory locations outside of those reserved for
        the HALT procedure are unmodified by the HALT procedure.
 Master Processor:
        The state of the master processor shall be restored to the state
        it had on entrance to the HALT procedure.  NOTE: a machine check
        taken during the machine-check-logout HALT procedure will result in
        a checkstop.
 Slave Processors:
        The state of the slave processors shall not be altered by the
        machine-check-logout HALT procedure.
 IO Sub-system:
        The state of the IO sub-system shall not be altered by the
        machine-check-logout HALT procedure.
 Interrupt Sub-system:
        The processor's MSR EE=0.



[ P1275 Item #232 -- Received: Mon Feb  6 14:34:43 PST 1995 ]