8818760512
This patch fixes a race in the command reference counting logic by putting spinlocks around kobject_put() in the command_put function. - Also added debug messages. - Changed a memcpy to memcpy_fromio since we are reading from io space. Signed-off-by: Max Asbock <masbock@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
100 lines
3.1 KiB
C
100 lines
3.1 KiB
C
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/*
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* IBM ASM Service Processor Device Driver
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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* Copyright (C) IBM Corporation, 2004
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*
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* Author: Max Asböck <amax@us.ibm.com>
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*
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*/
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#include <linux/notifier.h>
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#include "ibmasm.h"
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#include "dot_command.h"
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#include "lowlevel.h"
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static int suspend_heartbeats = 0;
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/*
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* Once the driver indicates to the service processor that it is running
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* - see send_os_state() - the service processor sends periodic heartbeats
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* to the driver. The driver must respond to the heartbeats or else the OS
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* will be rebooted.
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* In the case of a panic the interrupt handler continues to work and thus
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* continues to respond to heartbeats, making the service processor believe
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* the OS is still running and thus preventing a reboot.
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* To prevent this from happening a callback is added the panic_notifier_list.
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* Before responding to a heartbeat the driver checks if a panic has happened,
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* if yes it suspends heartbeat, causing the service processor to reboot as
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* expected.
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*/
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static int panic_happened(struct notifier_block *n, unsigned long val, void *v)
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{
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suspend_heartbeats = 1;
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return 0;
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}
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static struct notifier_block panic_notifier = { panic_happened, NULL, 1 };
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void ibmasm_register_panic_notifier(void)
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{
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notifier_chain_register(&panic_notifier_list, &panic_notifier);
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}
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void ibmasm_unregister_panic_notifier(void)
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{
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notifier_chain_unregister(&panic_notifier_list, &panic_notifier);
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}
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int ibmasm_heartbeat_init(struct service_processor *sp)
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{
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sp->heartbeat = ibmasm_new_command(sp, HEARTBEAT_BUFFER_SIZE);
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if (sp->heartbeat == NULL)
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return -ENOMEM;
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return 0;
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}
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void ibmasm_heartbeat_exit(struct service_processor *sp)
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{
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char tsbuf[32];
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dbg("%s:%d at %s\n", __FUNCTION__, __LINE__, get_timestamp(tsbuf));
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ibmasm_wait_for_response(sp->heartbeat, IBMASM_CMD_TIMEOUT_NORMAL);
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dbg("%s:%d at %s\n", __FUNCTION__, __LINE__, get_timestamp(tsbuf));
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suspend_heartbeats = 1;
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command_put(sp->heartbeat);
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}
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void ibmasm_receive_heartbeat(struct service_processor *sp, void *message, size_t size)
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{
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struct command *cmd = sp->heartbeat;
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struct dot_command_header *header = (struct dot_command_header *)cmd->buffer;
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char tsbuf[32];
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dbg("%s:%d at %s\n", __FUNCTION__, __LINE__, get_timestamp(tsbuf));
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if (suspend_heartbeats)
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return;
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/* return the received dot command to sender */
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cmd->status = IBMASM_CMD_PENDING;
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size = min(size, cmd->buffer_size);
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memcpy_fromio(cmd->buffer, message, size);
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header->type = sp_write;
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ibmasm_exec_command(sp, cmd);
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}
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