linux/arch/ia64/kernel/err_inject.c
Srivatsa S. Bhat f2e48a8905 ia64, err-inject: Fix CPU hotplug callback registration
Subsystems that want to register CPU hotplug callbacks, as well as perform
initialization for the CPUs that are already online, often do it as shown
below:

	get_online_cpus();

	for_each_online_cpu(cpu)
		init_cpu(cpu);

	register_cpu_notifier(&foobar_cpu_notifier);

	put_online_cpus();

This is wrong, since it is prone to ABBA deadlocks involving the
cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently
with CPU hotplug operations).

Instead, the correct and race-free way of performing the callback
registration is:

	cpu_notifier_register_begin();

	for_each_online_cpu(cpu)
		init_cpu(cpu);

	/* Note the use of the double underscored version of the API */
	__register_cpu_notifier(&foobar_cpu_notifier);

	cpu_notifier_register_done();

Fix the error injection code in ia64 by using this latter form of callback
registration.

Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-03-20 13:43:41 +01:00

315 lines
7.8 KiB
C

/*
* err_inject.c -
* 1.) Inject errors to a processor.
* 2.) Query error injection capabilities.
* This driver along with user space code can be acting as an error
* injection tool.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* Written by: Fenghua Yu <fenghua.yu@intel.com>, Intel Corporation
* Copyright (C) 2006, Intel Corp. All rights reserved.
*
*/
#include <linux/device.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/cpu.h>
#include <linux/module.h>
#define ERR_INJ_DEBUG
#define ERR_DATA_BUFFER_SIZE 3 // Three 8-byte;
#define define_one_ro(name) \
static DEVICE_ATTR(name, 0444, show_##name, NULL)
#define define_one_rw(name) \
static DEVICE_ATTR(name, 0644, show_##name, store_##name)
static u64 call_start[NR_CPUS];
static u64 phys_addr[NR_CPUS];
static u64 err_type_info[NR_CPUS];
static u64 err_struct_info[NR_CPUS];
static struct {
u64 data1;
u64 data2;
u64 data3;
} __attribute__((__aligned__(16))) err_data_buffer[NR_CPUS];
static s64 status[NR_CPUS];
static u64 capabilities[NR_CPUS];
static u64 resources[NR_CPUS];
#define show(name) \
static ssize_t \
show_##name(struct device *dev, struct device_attribute *attr, \
char *buf) \
{ \
u32 cpu=dev->id; \
return sprintf(buf, "%lx\n", name[cpu]); \
}
#define store(name) \
static ssize_t \
store_##name(struct device *dev, struct device_attribute *attr, \
const char *buf, size_t size) \
{ \
unsigned int cpu=dev->id; \
name[cpu] = simple_strtoull(buf, NULL, 16); \
return size; \
}
show(call_start)
/* It's user's responsibility to call the PAL procedure on a specific
* processor. The cpu number in driver is only used for storing data.
*/
static ssize_t
store_call_start(struct device *dev, struct device_attribute *attr,
const char *buf, size_t size)
{
unsigned int cpu=dev->id;
unsigned long call_start = simple_strtoull(buf, NULL, 16);
#ifdef ERR_INJ_DEBUG
printk(KERN_DEBUG "pal_mc_err_inject for cpu%d:\n", cpu);
printk(KERN_DEBUG "err_type_info=%lx,\n", err_type_info[cpu]);
printk(KERN_DEBUG "err_struct_info=%lx,\n", err_struct_info[cpu]);
printk(KERN_DEBUG "err_data_buffer=%lx, %lx, %lx.\n",
err_data_buffer[cpu].data1,
err_data_buffer[cpu].data2,
err_data_buffer[cpu].data3);
#endif
switch (call_start) {
case 0: /* Do nothing. */
break;
case 1: /* Call pal_mc_error_inject in physical mode. */
status[cpu]=ia64_pal_mc_error_inject_phys(err_type_info[cpu],
err_struct_info[cpu],
ia64_tpa(&err_data_buffer[cpu]),
&capabilities[cpu],
&resources[cpu]);
break;
case 2: /* Call pal_mc_error_inject in virtual mode. */
status[cpu]=ia64_pal_mc_error_inject_virt(err_type_info[cpu],
err_struct_info[cpu],
ia64_tpa(&err_data_buffer[cpu]),
&capabilities[cpu],
&resources[cpu]);
break;
default:
status[cpu] = -EINVAL;
break;
}
#ifdef ERR_INJ_DEBUG
printk(KERN_DEBUG "Returns: status=%d,\n", (int)status[cpu]);
printk(KERN_DEBUG "capapbilities=%lx,\n", capabilities[cpu]);
printk(KERN_DEBUG "resources=%lx\n", resources[cpu]);
#endif
return size;
}
show(err_type_info)
store(err_type_info)
static ssize_t
show_virtual_to_phys(struct device *dev, struct device_attribute *attr,
char *buf)
{
unsigned int cpu=dev->id;
return sprintf(buf, "%lx\n", phys_addr[cpu]);
}
static ssize_t
store_virtual_to_phys(struct device *dev, struct device_attribute *attr,
const char *buf, size_t size)
{
unsigned int cpu=dev->id;
u64 virt_addr=simple_strtoull(buf, NULL, 16);
int ret;
ret = get_user_pages(current, current->mm, virt_addr,
1, VM_READ, 0, NULL, NULL);
if (ret<=0) {
#ifdef ERR_INJ_DEBUG
printk("Virtual address %lx is not existing.\n",virt_addr);
#endif
return -EINVAL;
}
phys_addr[cpu] = ia64_tpa(virt_addr);
return size;
}
show(err_struct_info)
store(err_struct_info)
static ssize_t
show_err_data_buffer(struct device *dev,
struct device_attribute *attr, char *buf)
{
unsigned int cpu=dev->id;
return sprintf(buf, "%lx, %lx, %lx\n",
err_data_buffer[cpu].data1,
err_data_buffer[cpu].data2,
err_data_buffer[cpu].data3);
}
static ssize_t
store_err_data_buffer(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t size)
{
unsigned int cpu=dev->id;
int ret;
#ifdef ERR_INJ_DEBUG
printk("write err_data_buffer=[%lx,%lx,%lx] on cpu%d\n",
err_data_buffer[cpu].data1,
err_data_buffer[cpu].data2,
err_data_buffer[cpu].data3,
cpu);
#endif
ret=sscanf(buf, "%lx, %lx, %lx",
&err_data_buffer[cpu].data1,
&err_data_buffer[cpu].data2,
&err_data_buffer[cpu].data3);
if (ret!=ERR_DATA_BUFFER_SIZE)
return -EINVAL;
return size;
}
show(status)
show(capabilities)
show(resources)
define_one_rw(call_start);
define_one_rw(err_type_info);
define_one_rw(err_struct_info);
define_one_rw(err_data_buffer);
define_one_rw(virtual_to_phys);
define_one_ro(status);
define_one_ro(capabilities);
define_one_ro(resources);
static struct attribute *default_attrs[] = {
&dev_attr_call_start.attr,
&dev_attr_virtual_to_phys.attr,
&dev_attr_err_type_info.attr,
&dev_attr_err_struct_info.attr,
&dev_attr_err_data_buffer.attr,
&dev_attr_status.attr,
&dev_attr_capabilities.attr,
&dev_attr_resources.attr,
NULL
};
static struct attribute_group err_inject_attr_group = {
.attrs = default_attrs,
.name = "err_inject"
};
/* Add/Remove err_inject interface for CPU device */
static int err_inject_add_dev(struct device *sys_dev)
{
return sysfs_create_group(&sys_dev->kobj, &err_inject_attr_group);
}
static int err_inject_remove_dev(struct device *sys_dev)
{
sysfs_remove_group(&sys_dev->kobj, &err_inject_attr_group);
return 0;
}
static int err_inject_cpu_callback(struct notifier_block *nfb,
unsigned long action, void *hcpu)
{
unsigned int cpu = (unsigned long)hcpu;
struct device *sys_dev;
sys_dev = get_cpu_device(cpu);
switch (action) {
case CPU_ONLINE:
case CPU_ONLINE_FROZEN:
err_inject_add_dev(sys_dev);
break;
case CPU_DEAD:
case CPU_DEAD_FROZEN:
err_inject_remove_dev(sys_dev);
break;
}
return NOTIFY_OK;
}
static struct notifier_block err_inject_cpu_notifier =
{
.notifier_call = err_inject_cpu_callback,
};
static int __init
err_inject_init(void)
{
int i;
#ifdef ERR_INJ_DEBUG
printk(KERN_INFO "Enter error injection driver.\n");
#endif
cpu_notifier_register_begin();
for_each_online_cpu(i) {
err_inject_cpu_callback(&err_inject_cpu_notifier, CPU_ONLINE,
(void *)(long)i);
}
__register_hotcpu_notifier(&err_inject_cpu_notifier);
cpu_notifier_register_done();
return 0;
}
static void __exit
err_inject_exit(void)
{
int i;
struct device *sys_dev;
#ifdef ERR_INJ_DEBUG
printk(KERN_INFO "Exit error injection driver.\n");
#endif
cpu_notifier_register_begin();
for_each_online_cpu(i) {
sys_dev = get_cpu_device(i);
sysfs_remove_group(&sys_dev->kobj, &err_inject_attr_group);
}
__unregister_hotcpu_notifier(&err_inject_cpu_notifier);
cpu_notifier_register_done();
}
module_init(err_inject_init);
module_exit(err_inject_exit);
MODULE_AUTHOR("Fenghua Yu <fenghua.yu@intel.com>");
MODULE_DESCRIPTION("MC error injection kernel sysfs interface");
MODULE_LICENSE("GPL");