kernel-ark/drivers/s390/char/monreader.c
Arjan van de Ven d54b1fdb1d [PATCH] mark struct file_operations const 5
Many struct file_operations in the kernel can be "const".  Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data.  In addition it'll catch accidental writes at compile time to
these shared resources.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 09:48:45 -08:00

644 lines
17 KiB
C

/*
* drivers/s390/char/monreader.c
*
* Character device driver for reading z/VM *MONITOR service records.
*
* Copyright 2004 IBM Corporation, IBM Deutschland Entwicklung GmbH.
*
* Author: Gerald Schaefer <geraldsc@de.ibm.com>
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/ctype.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <asm/uaccess.h>
#include <asm/ebcdic.h>
#include <asm/extmem.h>
#include <linux/poll.h>
#include <net/iucv/iucv.h>
//#define MON_DEBUG /* Debug messages on/off */
#define MON_NAME "monreader"
#define P_INFO(x...) printk(KERN_INFO MON_NAME " info: " x)
#define P_ERROR(x...) printk(KERN_ERR MON_NAME " error: " x)
#define P_WARNING(x...) printk(KERN_WARNING MON_NAME " warning: " x)
#ifdef MON_DEBUG
#define P_DEBUG(x...) printk(KERN_DEBUG MON_NAME " debug: " x)
#else
#define P_DEBUG(x...) do {} while (0)
#endif
#define MON_COLLECT_SAMPLE 0x80
#define MON_COLLECT_EVENT 0x40
#define MON_SERVICE "*MONITOR"
#define MON_IN_USE 0x01
#define MON_MSGLIM 255
static char mon_dcss_name[9] = "MONDCSS\0";
struct mon_msg {
u32 pos;
u32 mca_offset;
struct iucv_message msg;
char msglim_reached;
char replied_msglim;
};
struct mon_private {
struct iucv_path *path;
struct mon_msg *msg_array[MON_MSGLIM];
unsigned int write_index;
unsigned int read_index;
atomic_t msglim_count;
atomic_t read_ready;
atomic_t iucv_connected;
atomic_t iucv_severed;
};
static unsigned long mon_in_use = 0;
static unsigned long mon_dcss_start;
static unsigned long mon_dcss_end;
static DECLARE_WAIT_QUEUE_HEAD(mon_read_wait_queue);
static DECLARE_WAIT_QUEUE_HEAD(mon_conn_wait_queue);
static u8 user_data_connect[16] = {
/* Version code, must be 0x01 for shared mode */
0x01,
/* what to collect */
MON_COLLECT_SAMPLE | MON_COLLECT_EVENT,
/* DCSS name in EBCDIC, 8 bytes padded with blanks */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
};
static u8 user_data_sever[16] = {
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
};
/******************************************************************************
* helper functions *
*****************************************************************************/
/*
* Create the 8 bytes EBCDIC DCSS segment name from
* an ASCII name, incl. padding
*/
static inline void dcss_mkname(char *ascii_name, char *ebcdic_name)
{
int i;
for (i = 0; i < 8; i++) {
if (ascii_name[i] == '\0')
break;
ebcdic_name[i] = toupper(ascii_name[i]);
};
for (; i < 8; i++)
ebcdic_name[i] = ' ';
ASCEBC(ebcdic_name, 8);
}
/*
* print appropriate error message for segment_load()/segment_type()
* return code
*/
static void mon_segment_warn(int rc, char* seg_name)
{
switch (rc) {
case -ENOENT:
P_WARNING("cannot load/query segment %s, does not exist\n",
seg_name);
break;
case -ENOSYS:
P_WARNING("cannot load/query segment %s, not running on VM\n",
seg_name);
break;
case -EIO:
P_WARNING("cannot load/query segment %s, hardware error\n",
seg_name);
break;
case -ENOTSUPP:
P_WARNING("cannot load/query segment %s, is a multi-part "
"segment\n", seg_name);
break;
case -ENOSPC:
P_WARNING("cannot load/query segment %s, overlaps with "
"storage\n", seg_name);
break;
case -EBUSY:
P_WARNING("cannot load/query segment %s, overlaps with "
"already loaded dcss\n", seg_name);
break;
case -EPERM:
P_WARNING("cannot load/query segment %s, already loaded in "
"incompatible mode\n", seg_name);
break;
case -ENOMEM:
P_WARNING("cannot load/query segment %s, out of memory\n",
seg_name);
break;
case -ERANGE:
P_WARNING("cannot load/query segment %s, exceeds kernel "
"mapping range\n", seg_name);
break;
default:
P_WARNING("cannot load/query segment %s, return value %i\n",
seg_name, rc);
break;
}
}
static inline unsigned long mon_mca_start(struct mon_msg *monmsg)
{
return *(u32 *) &monmsg->msg.rmmsg;
}
static inline unsigned long mon_mca_end(struct mon_msg *monmsg)
{
return *(u32 *) &monmsg->msg.rmmsg[4];
}
static inline u8 mon_mca_type(struct mon_msg *monmsg, u8 index)
{
return *((u8 *) mon_mca_start(monmsg) + monmsg->mca_offset + index);
}
static inline u32 mon_mca_size(struct mon_msg *monmsg)
{
return mon_mca_end(monmsg) - mon_mca_start(monmsg) + 1;
}
static inline u32 mon_rec_start(struct mon_msg *monmsg)
{
return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 4));
}
static inline u32 mon_rec_end(struct mon_msg *monmsg)
{
return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 8));
}
static inline int mon_check_mca(struct mon_msg *monmsg)
{
if ((mon_rec_end(monmsg) <= mon_rec_start(monmsg)) ||
(mon_rec_start(monmsg) < mon_dcss_start) ||
(mon_rec_end(monmsg) > mon_dcss_end) ||
(mon_mca_type(monmsg, 0) == 0) ||
(mon_mca_size(monmsg) % 12 != 0) ||
(mon_mca_end(monmsg) <= mon_mca_start(monmsg)) ||
(mon_mca_end(monmsg) > mon_dcss_end) ||
(mon_mca_start(monmsg) < mon_dcss_start) ||
((mon_mca_type(monmsg, 1) == 0) && (mon_mca_type(monmsg, 2) == 0)))
{
P_DEBUG("READ, IGNORED INVALID MCA\n\n");
return -EINVAL;
}
return 0;
}
static inline int mon_send_reply(struct mon_msg *monmsg,
struct mon_private *monpriv)
{
int rc;
P_DEBUG("read, REPLY: pathid = 0x%04X, msgid = 0x%08X, trgcls = "
"0x%08X\n\n",
monpriv->path->pathid, monmsg->msg.id, monmsg->msg.class);
rc = iucv_message_reply(monpriv->path, &monmsg->msg,
IUCV_IPRMDATA, NULL, 0);
atomic_dec(&monpriv->msglim_count);
if (likely(!monmsg->msglim_reached)) {
monmsg->pos = 0;
monmsg->mca_offset = 0;
monpriv->read_index = (monpriv->read_index + 1) %
MON_MSGLIM;
atomic_dec(&monpriv->read_ready);
} else
monmsg->replied_msglim = 1;
if (rc) {
P_ERROR("read, IUCV reply failed with rc = %i\n\n", rc);
return -EIO;
}
return 0;
}
static inline void mon_free_mem(struct mon_private *monpriv)
{
int i;
for (i = 0; i < MON_MSGLIM; i++)
if (monpriv->msg_array[i])
kfree(monpriv->msg_array[i]);
kfree(monpriv);
}
static inline struct mon_private *mon_alloc_mem(void)
{
int i;
struct mon_private *monpriv;
monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL);
if (!monpriv) {
P_ERROR("no memory for monpriv\n");
return NULL;
}
for (i = 0; i < MON_MSGLIM; i++) {
monpriv->msg_array[i] = kzalloc(sizeof(struct mon_msg),
GFP_KERNEL);
if (!monpriv->msg_array[i]) {
P_ERROR("open, no memory for msg_array\n");
mon_free_mem(monpriv);
return NULL;
}
}
return monpriv;
}
static inline void mon_read_debug(struct mon_msg *monmsg,
struct mon_private *monpriv)
{
#ifdef MON_DEBUG
u8 msg_type[2], mca_type;
unsigned long records_len;
records_len = mon_rec_end(monmsg) - mon_rec_start(monmsg) + 1;
memcpy(msg_type, &monmsg->msg.class, 2);
EBCASC(msg_type, 2);
mca_type = mon_mca_type(monmsg, 0);
EBCASC(&mca_type, 1);
P_DEBUG("read, mon_read_index = %i, mon_write_index = %i\n",
monpriv->read_index, monpriv->write_index);
P_DEBUG("read, pathid = 0x%04X, msgid = 0x%08X, trgcls = 0x%08X\n",
monpriv->path->pathid, monmsg->msg.id, monmsg->msg.class);
P_DEBUG("read, msg_type = '%c%c', mca_type = '%c' / 0x%X / 0x%X\n",
msg_type[0], msg_type[1], mca_type ? mca_type : 'X',
mon_mca_type(monmsg, 1), mon_mca_type(monmsg, 2));
P_DEBUG("read, MCA: start = 0x%lX, end = 0x%lX\n",
mon_mca_start(monmsg), mon_mca_end(monmsg));
P_DEBUG("read, REC: start = 0x%X, end = 0x%X, len = %lu\n\n",
mon_rec_start(monmsg), mon_rec_end(monmsg), records_len);
if (mon_mca_size(monmsg) > 12)
P_DEBUG("READ, MORE THAN ONE MCA\n\n");
#endif
}
static inline void mon_next_mca(struct mon_msg *monmsg)
{
if (likely((mon_mca_size(monmsg) - monmsg->mca_offset) == 12))
return;
P_DEBUG("READ, NEXT MCA\n\n");
monmsg->mca_offset += 12;
monmsg->pos = 0;
}
static inline struct mon_msg *mon_next_message(struct mon_private *monpriv)
{
struct mon_msg *monmsg;
if (!atomic_read(&monpriv->read_ready))
return NULL;
monmsg = monpriv->msg_array[monpriv->read_index];
if (unlikely(monmsg->replied_msglim)) {
monmsg->replied_msglim = 0;
monmsg->msglim_reached = 0;
monmsg->pos = 0;
monmsg->mca_offset = 0;
P_WARNING("read, message limit reached\n");
monpriv->read_index = (monpriv->read_index + 1) %
MON_MSGLIM;
atomic_dec(&monpriv->read_ready);
return ERR_PTR(-EOVERFLOW);
}
return monmsg;
}
/******************************************************************************
* IUCV handler *
*****************************************************************************/
static void mon_iucv_path_complete(struct iucv_path *path, u8 ipuser[16])
{
struct mon_private *monpriv = path->private;
P_DEBUG("IUCV connection completed\n");
P_DEBUG("IUCV ACCEPT (from *MONITOR): Version = 0x%02X, Event = "
"0x%02X, Sample = 0x%02X\n",
ipuser[0], ipuser[1], ipuser[2]);
atomic_set(&monpriv->iucv_connected, 1);
wake_up(&mon_conn_wait_queue);
}
static void mon_iucv_path_severed(struct iucv_path *path, u8 ipuser[16])
{
struct mon_private *monpriv = path->private;
P_ERROR("IUCV connection severed with rc = 0x%X\n", ipuser[0]);
iucv_path_sever(path, NULL);
atomic_set(&monpriv->iucv_severed, 1);
wake_up(&mon_conn_wait_queue);
wake_up_interruptible(&mon_read_wait_queue);
}
static void mon_iucv_message_pending(struct iucv_path *path,
struct iucv_message *msg)
{
struct mon_private *monpriv = path->private;
P_DEBUG("IUCV message pending\n");
memcpy(&monpriv->msg_array[monpriv->write_index]->msg,
msg, sizeof(*msg));
if (atomic_inc_return(&monpriv->msglim_count) == MON_MSGLIM) {
P_WARNING("IUCV message pending, message limit (%i) reached\n",
MON_MSGLIM);
monpriv->msg_array[monpriv->write_index]->msglim_reached = 1;
}
monpriv->write_index = (monpriv->write_index + 1) % MON_MSGLIM;
atomic_inc(&monpriv->read_ready);
wake_up_interruptible(&mon_read_wait_queue);
}
static struct iucv_handler monreader_iucv_handler = {
.path_complete = mon_iucv_path_complete,
.path_severed = mon_iucv_path_severed,
.message_pending = mon_iucv_message_pending,
};
/******************************************************************************
* file operations *
*****************************************************************************/
static int mon_open(struct inode *inode, struct file *filp)
{
struct mon_private *monpriv;
int rc;
/*
* only one user allowed
*/
rc = -EBUSY;
if (test_and_set_bit(MON_IN_USE, &mon_in_use))
goto out;
rc = -ENOMEM;
monpriv = mon_alloc_mem();
if (!monpriv)
goto out_use;
/*
* Connect to *MONITOR service
*/
monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL);
if (!monpriv->path)
goto out_priv;
rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler,
MON_SERVICE, NULL, user_data_connect, monpriv);
if (rc) {
P_ERROR("iucv connection to *MONITOR failed with "
"IPUSER SEVER code = %i\n", rc);
rc = -EIO;
goto out_path;
}
/*
* Wait for connection confirmation
*/
wait_event(mon_conn_wait_queue,
atomic_read(&monpriv->iucv_connected) ||
atomic_read(&monpriv->iucv_severed));
if (atomic_read(&monpriv->iucv_severed)) {
atomic_set(&monpriv->iucv_severed, 0);
atomic_set(&monpriv->iucv_connected, 0);
rc = -EIO;
goto out_path;
}
P_INFO("open, established connection to *MONITOR service\n\n");
filp->private_data = monpriv;
return nonseekable_open(inode, filp);
out_path:
kfree(monpriv->path);
out_priv:
mon_free_mem(monpriv);
out_use:
clear_bit(MON_IN_USE, &mon_in_use);
out:
return rc;
}
static int mon_close(struct inode *inode, struct file *filp)
{
int rc, i;
struct mon_private *monpriv = filp->private_data;
/*
* Close IUCV connection and unregister
*/
rc = iucv_path_sever(monpriv->path, user_data_sever);
if (rc)
P_ERROR("close, iucv_sever failed with rc = %i\n", rc);
else
P_INFO("close, terminated connection to *MONITOR service\n");
atomic_set(&monpriv->iucv_severed, 0);
atomic_set(&monpriv->iucv_connected, 0);
atomic_set(&monpriv->read_ready, 0);
atomic_set(&monpriv->msglim_count, 0);
monpriv->write_index = 0;
monpriv->read_index = 0;
for (i = 0; i < MON_MSGLIM; i++)
kfree(monpriv->msg_array[i]);
kfree(monpriv);
clear_bit(MON_IN_USE, &mon_in_use);
return 0;
}
static ssize_t mon_read(struct file *filp, char __user *data,
size_t count, loff_t *ppos)
{
struct mon_private *monpriv = filp->private_data;
struct mon_msg *monmsg;
int ret;
u32 mce_start;
monmsg = mon_next_message(monpriv);
if (IS_ERR(monmsg))
return PTR_ERR(monmsg);
if (!monmsg) {
if (filp->f_flags & O_NONBLOCK)
return -EAGAIN;
ret = wait_event_interruptible(mon_read_wait_queue,
atomic_read(&monpriv->read_ready) ||
atomic_read(&monpriv->iucv_severed));
if (ret)
return ret;
if (unlikely(atomic_read(&monpriv->iucv_severed)))
return -EIO;
monmsg = monpriv->msg_array[monpriv->read_index];
}
if (!monmsg->pos) {
monmsg->pos = mon_mca_start(monmsg) + monmsg->mca_offset;
mon_read_debug(monmsg, monpriv);
}
if (mon_check_mca(monmsg))
goto reply;
/* read monitor control element (12 bytes) first */
mce_start = mon_mca_start(monmsg) + monmsg->mca_offset;
if ((monmsg->pos >= mce_start) && (monmsg->pos < mce_start + 12)) {
count = min(count, (size_t) mce_start + 12 - monmsg->pos);
ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
count);
if (ret)
return -EFAULT;
monmsg->pos += count;
if (monmsg->pos == mce_start + 12)
monmsg->pos = mon_rec_start(monmsg);
goto out_copy;
}
/* read records */
if (monmsg->pos <= mon_rec_end(monmsg)) {
count = min(count, (size_t) mon_rec_end(monmsg) - monmsg->pos
+ 1);
ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
count);
if (ret)
return -EFAULT;
monmsg->pos += count;
if (monmsg->pos > mon_rec_end(monmsg))
mon_next_mca(monmsg);
goto out_copy;
}
reply:
ret = mon_send_reply(monmsg, monpriv);
return ret;
out_copy:
*ppos += count;
return count;
}
static unsigned int mon_poll(struct file *filp, struct poll_table_struct *p)
{
struct mon_private *monpriv = filp->private_data;
poll_wait(filp, &mon_read_wait_queue, p);
if (unlikely(atomic_read(&monpriv->iucv_severed)))
return POLLERR;
if (atomic_read(&monpriv->read_ready))
return POLLIN | POLLRDNORM;
return 0;
}
static const struct file_operations mon_fops = {
.owner = THIS_MODULE,
.open = &mon_open,
.release = &mon_close,
.read = &mon_read,
.poll = &mon_poll,
};
static struct miscdevice mon_dev = {
.name = "monreader",
.fops = &mon_fops,
.minor = MISC_DYNAMIC_MINOR,
};
/******************************************************************************
* module init/exit *
*****************************************************************************/
static int __init mon_init(void)
{
int rc;
if (!MACHINE_IS_VM) {
P_ERROR("not running under z/VM, driver not loaded\n");
return -ENODEV;
}
/*
* Register with IUCV and connect to *MONITOR service
*/
rc = iucv_register(&monreader_iucv_handler, 1);
if (rc) {
P_ERROR("failed to register with iucv driver\n");
return rc;
}
P_INFO("open, registered with IUCV\n");
rc = segment_type(mon_dcss_name);
if (rc < 0) {
mon_segment_warn(rc, mon_dcss_name);
goto out_iucv;
}
if (rc != SEG_TYPE_SC) {
P_ERROR("segment %s has unsupported type, should be SC\n",
mon_dcss_name);
rc = -EINVAL;
goto out_iucv;
}
rc = segment_load(mon_dcss_name, SEGMENT_SHARED,
&mon_dcss_start, &mon_dcss_end);
if (rc < 0) {
mon_segment_warn(rc, mon_dcss_name);
rc = -EINVAL;
goto out_iucv;
}
dcss_mkname(mon_dcss_name, &user_data_connect[8]);
rc = misc_register(&mon_dev);
if (rc < 0 ) {
P_ERROR("misc_register failed, rc = %i\n", rc);
goto out;
}
P_INFO("Loaded segment %s from %p to %p, size = %lu Byte\n",
mon_dcss_name, (void *) mon_dcss_start, (void *) mon_dcss_end,
mon_dcss_end - mon_dcss_start + 1);
return 0;
out:
segment_unload(mon_dcss_name);
out_iucv:
iucv_unregister(&monreader_iucv_handler, 1);
return rc;
}
static void __exit mon_exit(void)
{
segment_unload(mon_dcss_name);
WARN_ON(misc_deregister(&mon_dev) != 0);
iucv_unregister(&monreader_iucv_handler, 1);
return;
}
module_init(mon_init);
module_exit(mon_exit);
module_param_string(mondcss, mon_dcss_name, 9, 0444);
MODULE_PARM_DESC(mondcss, "Name of DCSS segment to be used for *MONITOR "
"service, max. 8 chars. Default is MONDCSS");
MODULE_AUTHOR("Gerald Schaefer <geraldsc@de.ibm.com>");
MODULE_DESCRIPTION("Character device driver for reading z/VM "
"monitor service records.");
MODULE_LICENSE("GPL");