kernel-ark/drivers/char/hvc_iucv.c
Hendrik Brueckner 91a970d988 [S390] hvc_iucv: allocate memory buffers for IUCV in zone DMA
The device driver must allocate memory for IUCV buffers with GFP_DMA,
because IUCV cannot address memory above 2GB (31bit addresses only).

Because the IUCV ignores the higher bits of the address, sending and
receiving IUCV data with this driver might cause memory corruptions.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-03-08 12:25:29 +01:00

1334 lines
37 KiB
C

/*
* hvc_iucv.c - z/VM IUCV hypervisor console (HVC) device driver
*
* This HVC device driver provides terminal access using
* z/VM IUCV communication paths.
*
* Copyright IBM Corp. 2008, 2009
*
* Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
*/
#define KMSG_COMPONENT "hvc_iucv"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/types.h>
#include <asm/ebcdic.h>
#include <linux/ctype.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/mempool.h>
#include <linux/moduleparam.h>
#include <linux/tty.h>
#include <linux/wait.h>
#include <net/iucv/iucv.h>
#include "hvc_console.h"
/* General device driver settings */
#define HVC_IUCV_MAGIC 0xc9e4c3e5
#define MAX_HVC_IUCV_LINES HVC_ALLOC_TTY_ADAPTERS
#define MEMPOOL_MIN_NR (PAGE_SIZE / sizeof(struct iucv_tty_buffer)/4)
/* IUCV TTY message */
#define MSG_VERSION 0x02 /* Message version */
#define MSG_TYPE_ERROR 0x01 /* Error message */
#define MSG_TYPE_TERMENV 0x02 /* Terminal environment variable */
#define MSG_TYPE_TERMIOS 0x04 /* Terminal IO struct update */
#define MSG_TYPE_WINSIZE 0x08 /* Terminal window size update */
#define MSG_TYPE_DATA 0x10 /* Terminal data */
struct iucv_tty_msg {
u8 version; /* Message version */
u8 type; /* Message type */
#define MSG_MAX_DATALEN ((u16)(~0))
u16 datalen; /* Payload length */
u8 data[]; /* Payload buffer */
} __attribute__((packed));
#define MSG_SIZE(s) ((s) + offsetof(struct iucv_tty_msg, data))
enum iucv_state_t {
IUCV_DISCONN = 0,
IUCV_CONNECTED = 1,
IUCV_SEVERED = 2,
};
enum tty_state_t {
TTY_CLOSED = 0,
TTY_OPENED = 1,
};
struct hvc_iucv_private {
struct hvc_struct *hvc; /* HVC struct reference */
u8 srv_name[8]; /* IUCV service name (ebcdic) */
unsigned char is_console; /* Linux console usage flag */
enum iucv_state_t iucv_state; /* IUCV connection status */
enum tty_state_t tty_state; /* TTY status */
struct iucv_path *path; /* IUCV path pointer */
spinlock_t lock; /* hvc_iucv_private lock */
#define SNDBUF_SIZE (PAGE_SIZE) /* must be < MSG_MAX_DATALEN */
void *sndbuf; /* send buffer */
size_t sndbuf_len; /* length of send buffer */
#define QUEUE_SNDBUF_DELAY (HZ / 25)
struct delayed_work sndbuf_work; /* work: send iucv msg(s) */
wait_queue_head_t sndbuf_waitq; /* wait for send completion */
struct list_head tty_outqueue; /* outgoing IUCV messages */
struct list_head tty_inqueue; /* incoming IUCV messages */
struct device *dev; /* device structure */
};
struct iucv_tty_buffer {
struct list_head list; /* list pointer */
struct iucv_message msg; /* store an IUCV message */
size_t offset; /* data buffer offset */
struct iucv_tty_msg *mbuf; /* buffer to store input/output data */
};
/* IUCV callback handler */
static int hvc_iucv_path_pending(struct iucv_path *, u8[8], u8[16]);
static void hvc_iucv_path_severed(struct iucv_path *, u8[16]);
static void hvc_iucv_msg_pending(struct iucv_path *, struct iucv_message *);
static void hvc_iucv_msg_complete(struct iucv_path *, struct iucv_message *);
/* Kernel module parameter: use one terminal device as default */
static unsigned long hvc_iucv_devices = 1;
/* Array of allocated hvc iucv tty lines... */
static struct hvc_iucv_private *hvc_iucv_table[MAX_HVC_IUCV_LINES];
#define IUCV_HVC_CON_IDX (0)
/* List of z/VM user ID filter entries (struct iucv_vmid_filter) */
#define MAX_VMID_FILTER (500)
static size_t hvc_iucv_filter_size;
static void *hvc_iucv_filter;
static const char *hvc_iucv_filter_string;
static DEFINE_RWLOCK(hvc_iucv_filter_lock);
/* Kmem cache and mempool for iucv_tty_buffer elements */
static struct kmem_cache *hvc_iucv_buffer_cache;
static mempool_t *hvc_iucv_mempool;
/* IUCV handler callback functions */
static struct iucv_handler hvc_iucv_handler = {
.path_pending = hvc_iucv_path_pending,
.path_severed = hvc_iucv_path_severed,
.message_complete = hvc_iucv_msg_complete,
.message_pending = hvc_iucv_msg_pending,
};
/**
* hvc_iucv_get_private() - Return a struct hvc_iucv_private instance.
* @num: The HVC virtual terminal number (vtermno)
*
* This function returns the struct hvc_iucv_private instance that corresponds
* to the HVC virtual terminal number specified as parameter @num.
*/
struct hvc_iucv_private *hvc_iucv_get_private(uint32_t num)
{
if ((num < HVC_IUCV_MAGIC) || (num - HVC_IUCV_MAGIC > hvc_iucv_devices))
return NULL;
return hvc_iucv_table[num - HVC_IUCV_MAGIC];
}
/**
* alloc_tty_buffer() - Return a new struct iucv_tty_buffer element.
* @size: Size of the internal buffer used to store data.
* @flags: Memory allocation flags passed to mempool.
*
* This function allocates a new struct iucv_tty_buffer element and, optionally,
* allocates an internal data buffer with the specified size @size.
* The internal data buffer is always allocated with GFP_DMA which is
* required for receiving and sending data with IUCV.
* Note: The total message size arises from the internal buffer size and the
* members of the iucv_tty_msg structure.
* The function returns NULL if memory allocation has failed.
*/
static struct iucv_tty_buffer *alloc_tty_buffer(size_t size, gfp_t flags)
{
struct iucv_tty_buffer *bufp;
bufp = mempool_alloc(hvc_iucv_mempool, flags);
if (!bufp)
return NULL;
memset(bufp, 0, sizeof(*bufp));
if (size > 0) {
bufp->msg.length = MSG_SIZE(size);
bufp->mbuf = kmalloc(bufp->msg.length, flags | GFP_DMA);
if (!bufp->mbuf) {
mempool_free(bufp, hvc_iucv_mempool);
return NULL;
}
bufp->mbuf->version = MSG_VERSION;
bufp->mbuf->type = MSG_TYPE_DATA;
bufp->mbuf->datalen = (u16) size;
}
return bufp;
}
/**
* destroy_tty_buffer() - destroy struct iucv_tty_buffer element.
* @bufp: Pointer to a struct iucv_tty_buffer element, SHALL NOT be NULL.
*/
static void destroy_tty_buffer(struct iucv_tty_buffer *bufp)
{
kfree(bufp->mbuf);
mempool_free(bufp, hvc_iucv_mempool);
}
/**
* destroy_tty_buffer_list() - call destroy_tty_buffer() for each list element.
* @list: List containing struct iucv_tty_buffer elements.
*/
static void destroy_tty_buffer_list(struct list_head *list)
{
struct iucv_tty_buffer *ent, *next;
list_for_each_entry_safe(ent, next, list, list) {
list_del(&ent->list);
destroy_tty_buffer(ent);
}
}
/**
* hvc_iucv_write() - Receive IUCV message & write data to HVC buffer.
* @priv: Pointer to struct hvc_iucv_private
* @buf: HVC buffer for writing received terminal data.
* @count: HVC buffer size.
* @has_more_data: Pointer to an int variable.
*
* The function picks up pending messages from the input queue and receives
* the message data that is then written to the specified buffer @buf.
* If the buffer size @count is less than the data message size, the
* message is kept on the input queue and @has_more_data is set to 1.
* If all message data has been written, the message is removed from
* the input queue.
*
* The function returns the number of bytes written to the terminal, zero if
* there are no pending data messages available or if there is no established
* IUCV path.
* If the IUCV path has been severed, then -EPIPE is returned to cause a
* hang up (that is issued by the HVC layer).
*/
static int hvc_iucv_write(struct hvc_iucv_private *priv,
char *buf, int count, int *has_more_data)
{
struct iucv_tty_buffer *rb;
int written;
int rc;
/* immediately return if there is no IUCV connection */
if (priv->iucv_state == IUCV_DISCONN)
return 0;
/* if the IUCV path has been severed, return -EPIPE to inform the
* HVC layer to hang up the tty device. */
if (priv->iucv_state == IUCV_SEVERED)
return -EPIPE;
/* check if there are pending messages */
if (list_empty(&priv->tty_inqueue))
return 0;
/* receive an iucv message and flip data to the tty (ldisc) */
rb = list_first_entry(&priv->tty_inqueue, struct iucv_tty_buffer, list);
written = 0;
if (!rb->mbuf) { /* message not yet received ... */
/* allocate mem to store msg data; if no memory is available
* then leave the buffer on the list and re-try later */
rb->mbuf = kmalloc(rb->msg.length, GFP_ATOMIC | GFP_DMA);
if (!rb->mbuf)
return -ENOMEM;
rc = __iucv_message_receive(priv->path, &rb->msg, 0,
rb->mbuf, rb->msg.length, NULL);
switch (rc) {
case 0: /* Successful */
break;
case 2: /* No message found */
case 9: /* Message purged */
break;
default:
written = -EIO;
}
/* remove buffer if an error has occured or received data
* is not correct */
if (rc || (rb->mbuf->version != MSG_VERSION) ||
(rb->msg.length != MSG_SIZE(rb->mbuf->datalen)))
goto out_remove_buffer;
}
switch (rb->mbuf->type) {
case MSG_TYPE_DATA:
written = min_t(int, rb->mbuf->datalen - rb->offset, count);
memcpy(buf, rb->mbuf->data + rb->offset, written);
if (written < (rb->mbuf->datalen - rb->offset)) {
rb->offset += written;
*has_more_data = 1;
goto out_written;
}
break;
case MSG_TYPE_WINSIZE:
if (rb->mbuf->datalen != sizeof(struct winsize))
break;
/* The caller must ensure that the hvc is locked, which
* is the case when called from hvc_iucv_get_chars() */
__hvc_resize(priv->hvc, *((struct winsize *) rb->mbuf->data));
break;
case MSG_TYPE_ERROR: /* ignored ... */
case MSG_TYPE_TERMENV: /* ignored ... */
case MSG_TYPE_TERMIOS: /* ignored ... */
break;
}
out_remove_buffer:
list_del(&rb->list);
destroy_tty_buffer(rb);
*has_more_data = !list_empty(&priv->tty_inqueue);
out_written:
return written;
}
/**
* hvc_iucv_get_chars() - HVC get_chars operation.
* @vtermno: HVC virtual terminal number.
* @buf: Pointer to a buffer to store data
* @count: Size of buffer available for writing
*
* The HVC thread calls this method to read characters from the back-end.
* If an IUCV communication path has been established, pending IUCV messages
* are received and data is copied into buffer @buf up to @count bytes.
*
* Locking: The routine gets called under an irqsave() spinlock; and
* the routine locks the struct hvc_iucv_private->lock to call
* helper functions.
*/
static int hvc_iucv_get_chars(uint32_t vtermno, char *buf, int count)
{
struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
int written;
int has_more_data;
if (count <= 0)
return 0;
if (!priv)
return -ENODEV;
spin_lock(&priv->lock);
has_more_data = 0;
written = hvc_iucv_write(priv, buf, count, &has_more_data);
spin_unlock(&priv->lock);
/* if there are still messages on the queue... schedule another run */
if (has_more_data)
hvc_kick();
return written;
}
/**
* hvc_iucv_queue() - Buffer terminal data for sending.
* @priv: Pointer to struct hvc_iucv_private instance.
* @buf: Buffer containing data to send.
* @count: Size of buffer and amount of data to send.
*
* The function queues data for sending. To actually send the buffered data,
* a work queue function is scheduled (with QUEUE_SNDBUF_DELAY).
* The function returns the number of data bytes that has been buffered.
*
* If the device is not connected, data is ignored and the function returns
* @count.
* If the buffer is full, the function returns 0.
* If an existing IUCV communicaton path has been severed, -EPIPE is returned
* (that can be passed to HVC layer to cause a tty hangup).
*/
static int hvc_iucv_queue(struct hvc_iucv_private *priv, const char *buf,
int count)
{
size_t len;
if (priv->iucv_state == IUCV_DISCONN)
return count; /* ignore data */
if (priv->iucv_state == IUCV_SEVERED)
return -EPIPE;
len = min_t(size_t, count, SNDBUF_SIZE - priv->sndbuf_len);
if (!len)
return 0;
memcpy(priv->sndbuf + priv->sndbuf_len, buf, len);
priv->sndbuf_len += len;
if (priv->iucv_state == IUCV_CONNECTED)
schedule_delayed_work(&priv->sndbuf_work, QUEUE_SNDBUF_DELAY);
return len;
}
/**
* hvc_iucv_send() - Send an IUCV message containing terminal data.
* @priv: Pointer to struct hvc_iucv_private instance.
*
* If an IUCV communication path has been established, the buffered output data
* is sent via an IUCV message and the number of bytes sent is returned.
* Returns 0 if there is no established IUCV communication path or
* -EPIPE if an existing IUCV communicaton path has been severed.
*/
static int hvc_iucv_send(struct hvc_iucv_private *priv)
{
struct iucv_tty_buffer *sb;
int rc, len;
if (priv->iucv_state == IUCV_SEVERED)
return -EPIPE;
if (priv->iucv_state == IUCV_DISCONN)
return -EIO;
if (!priv->sndbuf_len)
return 0;
/* allocate internal buffer to store msg data and also compute total
* message length */
sb = alloc_tty_buffer(priv->sndbuf_len, GFP_ATOMIC);
if (!sb)
return -ENOMEM;
memcpy(sb->mbuf->data, priv->sndbuf, priv->sndbuf_len);
sb->mbuf->datalen = (u16) priv->sndbuf_len;
sb->msg.length = MSG_SIZE(sb->mbuf->datalen);
list_add_tail(&sb->list, &priv->tty_outqueue);
rc = __iucv_message_send(priv->path, &sb->msg, 0, 0,
(void *) sb->mbuf, sb->msg.length);
if (rc) {
/* drop the message here; however we might want to handle
* 0x03 (msg limit reached) by trying again... */
list_del(&sb->list);
destroy_tty_buffer(sb);
}
len = priv->sndbuf_len;
priv->sndbuf_len = 0;
return len;
}
/**
* hvc_iucv_sndbuf_work() - Send buffered data over IUCV
* @work: Work structure.
*
* This work queue function sends buffered output data over IUCV and,
* if not all buffered data could be sent, reschedules itself.
*/
static void hvc_iucv_sndbuf_work(struct work_struct *work)
{
struct hvc_iucv_private *priv;
priv = container_of(work, struct hvc_iucv_private, sndbuf_work.work);
if (!priv)
return;
spin_lock_bh(&priv->lock);
hvc_iucv_send(priv);
spin_unlock_bh(&priv->lock);
}
/**
* hvc_iucv_put_chars() - HVC put_chars operation.
* @vtermno: HVC virtual terminal number.
* @buf: Pointer to an buffer to read data from
* @count: Size of buffer available for reading
*
* The HVC thread calls this method to write characters to the back-end.
* The function calls hvc_iucv_queue() to queue terminal data for sending.
*
* Locking: The method gets called under an irqsave() spinlock; and
* locks struct hvc_iucv_private->lock.
*/
static int hvc_iucv_put_chars(uint32_t vtermno, const char *buf, int count)
{
struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
int queued;
if (count <= 0)
return 0;
if (!priv)
return -ENODEV;
spin_lock(&priv->lock);
queued = hvc_iucv_queue(priv, buf, count);
spin_unlock(&priv->lock);
return queued;
}
/**
* hvc_iucv_notifier_add() - HVC notifier for opening a TTY for the first time.
* @hp: Pointer to the HVC device (struct hvc_struct)
* @id: Additional data (originally passed to hvc_alloc): the index of an struct
* hvc_iucv_private instance.
*
* The function sets the tty state to TTY_OPENED for the struct hvc_iucv_private
* instance that is derived from @id. Always returns 0.
*
* Locking: struct hvc_iucv_private->lock, spin_lock_bh
*/
static int hvc_iucv_notifier_add(struct hvc_struct *hp, int id)
{
struct hvc_iucv_private *priv;
priv = hvc_iucv_get_private(id);
if (!priv)
return 0;
spin_lock_bh(&priv->lock);
priv->tty_state = TTY_OPENED;
spin_unlock_bh(&priv->lock);
return 0;
}
/**
* hvc_iucv_cleanup() - Clean up and reset a z/VM IUCV HVC instance.
* @priv: Pointer to the struct hvc_iucv_private instance.
*/
static void hvc_iucv_cleanup(struct hvc_iucv_private *priv)
{
destroy_tty_buffer_list(&priv->tty_outqueue);
destroy_tty_buffer_list(&priv->tty_inqueue);
priv->tty_state = TTY_CLOSED;
priv->iucv_state = IUCV_DISCONN;
priv->sndbuf_len = 0;
}
/**
* tty_outqueue_empty() - Test if the tty outq is empty
* @priv: Pointer to struct hvc_iucv_private instance.
*/
static inline int tty_outqueue_empty(struct hvc_iucv_private *priv)
{
int rc;
spin_lock_bh(&priv->lock);
rc = list_empty(&priv->tty_outqueue);
spin_unlock_bh(&priv->lock);
return rc;
}
/**
* flush_sndbuf_sync() - Flush send buffer and wait for completion
* @priv: Pointer to struct hvc_iucv_private instance.
*
* The routine cancels a pending sndbuf work, calls hvc_iucv_send()
* to flush any buffered terminal output data and waits for completion.
*/
static void flush_sndbuf_sync(struct hvc_iucv_private *priv)
{
int sync_wait;
cancel_delayed_work_sync(&priv->sndbuf_work);
spin_lock_bh(&priv->lock);
hvc_iucv_send(priv); /* force sending buffered data */
sync_wait = !list_empty(&priv->tty_outqueue); /* anything queued ? */
spin_unlock_bh(&priv->lock);
if (sync_wait)
wait_event_timeout(priv->sndbuf_waitq,
tty_outqueue_empty(priv), HZ/10);
}
/**
* hvc_iucv_hangup() - Sever IUCV path and schedule hvc tty hang up
* @priv: Pointer to hvc_iucv_private structure
*
* This routine severs an existing IUCV communication path and hangs
* up the underlying HVC terminal device.
* The hang-up occurs only if an IUCV communication path is established;
* otherwise there is no need to hang up the terminal device.
*
* The IUCV HVC hang-up is separated into two steps:
* 1. After the IUCV path has been severed, the iucv_state is set to
* IUCV_SEVERED.
* 2. Later, when the HVC thread calls hvc_iucv_get_chars(), the
* IUCV_SEVERED state causes the tty hang-up in the HVC layer.
*
* If the tty has not yet been opened, clean up the hvc_iucv_private
* structure to allow re-connects.
* If the tty has been opened, let get_chars() return -EPIPE to signal
* the HVC layer to hang up the tty and, if so, wake up the HVC thread
* to call get_chars()...
*
* Special notes on hanging up a HVC terminal instantiated as console:
* Hang-up: 1. do_tty_hangup() replaces file ops (= hung_up_tty_fops)
* 2. do_tty_hangup() calls tty->ops->close() for console_filp
* => no hangup notifier is called by HVC (default)
* 2. hvc_close() returns because of tty_hung_up_p(filp)
* => no delete notifier is called!
* Finally, the back-end is not being notified, thus, the tty session is
* kept active (TTY_OPEN) to be ready for re-connects.
*
* Locking: spin_lock(&priv->lock) w/o disabling bh
*/
static void hvc_iucv_hangup(struct hvc_iucv_private *priv)
{
struct iucv_path *path;
path = NULL;
spin_lock(&priv->lock);
if (priv->iucv_state == IUCV_CONNECTED) {
path = priv->path;
priv->path = NULL;
priv->iucv_state = IUCV_SEVERED;
if (priv->tty_state == TTY_CLOSED)
hvc_iucv_cleanup(priv);
else
/* console is special (see above) */
if (priv->is_console) {
hvc_iucv_cleanup(priv);
priv->tty_state = TTY_OPENED;
} else
hvc_kick();
}
spin_unlock(&priv->lock);
/* finally sever path (outside of priv->lock due to lock ordering) */
if (path) {
iucv_path_sever(path, NULL);
iucv_path_free(path);
}
}
/**
* hvc_iucv_notifier_hangup() - HVC notifier for TTY hangups.
* @hp: Pointer to the HVC device (struct hvc_struct)
* @id: Additional data (originally passed to hvc_alloc):
* the index of an struct hvc_iucv_private instance.
*
* This routine notifies the HVC back-end that a tty hangup (carrier loss,
* virtual or otherwise) has occured.
* The z/VM IUCV HVC device driver ignores virtual hangups (vhangup())
* to keep an existing IUCV communication path established.
* (Background: vhangup() is called from user space (by getty or login) to
* disable writing to the tty by other applications).
* If the tty has been opened and an established IUCV path has been severed
* (we caused the tty hangup), the function calls hvc_iucv_cleanup().
*
* Locking: struct hvc_iucv_private->lock
*/
static void hvc_iucv_notifier_hangup(struct hvc_struct *hp, int id)
{
struct hvc_iucv_private *priv;
priv = hvc_iucv_get_private(id);
if (!priv)
return;
flush_sndbuf_sync(priv);
spin_lock_bh(&priv->lock);
/* NOTE: If the hangup was scheduled by ourself (from the iucv
* path_servered callback [IUCV_SEVERED]), we have to clean up
* our structure and to set state to TTY_CLOSED.
* If the tty was hung up otherwise (e.g. vhangup()), then we
* ignore this hangup and keep an established IUCV path open...
* (...the reason is that we are not able to connect back to the
* client if we disconnect on hang up) */
priv->tty_state = TTY_CLOSED;
if (priv->iucv_state == IUCV_SEVERED)
hvc_iucv_cleanup(priv);
spin_unlock_bh(&priv->lock);
}
/**
* hvc_iucv_notifier_del() - HVC notifier for closing a TTY for the last time.
* @hp: Pointer to the HVC device (struct hvc_struct)
* @id: Additional data (originally passed to hvc_alloc):
* the index of an struct hvc_iucv_private instance.
*
* This routine notifies the HVC back-end that the last tty device fd has been
* closed. The function calls hvc_iucv_cleanup() to clean up the struct
* hvc_iucv_private instance.
*
* Locking: struct hvc_iucv_private->lock
*/
static void hvc_iucv_notifier_del(struct hvc_struct *hp, int id)
{
struct hvc_iucv_private *priv;
struct iucv_path *path;
priv = hvc_iucv_get_private(id);
if (!priv)
return;
flush_sndbuf_sync(priv);
spin_lock_bh(&priv->lock);
path = priv->path; /* save reference to IUCV path */
priv->path = NULL;
hvc_iucv_cleanup(priv);
spin_unlock_bh(&priv->lock);
/* sever IUCV path outside of priv->lock due to lock ordering of:
* priv->lock <--> iucv_table_lock */
if (path) {
iucv_path_sever(path, NULL);
iucv_path_free(path);
}
}
/**
* hvc_iucv_filter_connreq() - Filter connection request based on z/VM user ID
* @ipvmid: Originating z/VM user ID (right padded with blanks)
*
* Returns 0 if the z/VM user ID @ipvmid is allowed to connection, otherwise
* non-zero.
*/
static int hvc_iucv_filter_connreq(u8 ipvmid[8])
{
size_t i;
/* Note: default policy is ACCEPT if no filter is set */
if (!hvc_iucv_filter_size)
return 0;
for (i = 0; i < hvc_iucv_filter_size; i++)
if (0 == memcmp(ipvmid, hvc_iucv_filter + (8 * i), 8))
return 0;
return 1;
}
/**
* hvc_iucv_path_pending() - IUCV handler to process a connection request.
* @path: Pending path (struct iucv_path)
* @ipvmid: z/VM system identifier of originator
* @ipuser: User specified data for this path
* (AF_IUCV: port/service name and originator port)
*
* The function uses the @ipuser data to determine if the pending path belongs
* to a terminal managed by this device driver.
* If the path belongs to this driver, ensure that the terminal is not accessed
* multiple times (only one connection to a terminal is allowed).
* If the terminal is not yet connected, the pending path is accepted and is
* associated to the appropriate struct hvc_iucv_private instance.
*
* Returns 0 if @path belongs to a terminal managed by the this device driver;
* otherwise returns -ENODEV in order to dispatch this path to other handlers.
*
* Locking: struct hvc_iucv_private->lock
*/
static int hvc_iucv_path_pending(struct iucv_path *path,
u8 ipvmid[8], u8 ipuser[16])
{
struct hvc_iucv_private *priv;
u8 nuser_data[16];
u8 vm_user_id[9];
int i, rc;
priv = NULL;
for (i = 0; i < hvc_iucv_devices; i++)
if (hvc_iucv_table[i] &&
(0 == memcmp(hvc_iucv_table[i]->srv_name, ipuser, 8))) {
priv = hvc_iucv_table[i];
break;
}
if (!priv)
return -ENODEV;
/* Enforce that ipvmid is allowed to connect to us */
read_lock(&hvc_iucv_filter_lock);
rc = hvc_iucv_filter_connreq(ipvmid);
read_unlock(&hvc_iucv_filter_lock);
if (rc) {
iucv_path_sever(path, ipuser);
iucv_path_free(path);
memcpy(vm_user_id, ipvmid, 8);
vm_user_id[8] = 0;
pr_info("A connection request from z/VM user ID %s "
"was refused\n", vm_user_id);
return 0;
}
spin_lock(&priv->lock);
/* If the terminal is already connected or being severed, then sever
* this path to enforce that there is only ONE established communication
* path per terminal. */
if (priv->iucv_state != IUCV_DISCONN) {
iucv_path_sever(path, ipuser);
iucv_path_free(path);
goto out_path_handled;
}
/* accept path */
memcpy(nuser_data, ipuser + 8, 8); /* remote service (for af_iucv) */
memcpy(nuser_data + 8, ipuser, 8); /* local service (for af_iucv) */
path->msglim = 0xffff; /* IUCV MSGLIMIT */
path->flags &= ~IUCV_IPRMDATA; /* TODO: use IUCV_IPRMDATA */
rc = iucv_path_accept(path, &hvc_iucv_handler, nuser_data, priv);
if (rc) {
iucv_path_sever(path, ipuser);
iucv_path_free(path);
goto out_path_handled;
}
priv->path = path;
priv->iucv_state = IUCV_CONNECTED;
/* flush buffered output data... */
schedule_delayed_work(&priv->sndbuf_work, 5);
out_path_handled:
spin_unlock(&priv->lock);
return 0;
}
/**
* hvc_iucv_path_severed() - IUCV handler to process a path sever.
* @path: Pending path (struct iucv_path)
* @ipuser: User specified data for this path
* (AF_IUCV: port/service name and originator port)
*
* This function calls the hvc_iucv_hangup() function for the
* respective IUCV HVC terminal.
*
* Locking: struct hvc_iucv_private->lock
*/
static void hvc_iucv_path_severed(struct iucv_path *path, u8 ipuser[16])
{
struct hvc_iucv_private *priv = path->private;
hvc_iucv_hangup(priv);
}
/**
* hvc_iucv_msg_pending() - IUCV handler to process an incoming IUCV message.
* @path: Pending path (struct iucv_path)
* @msg: Pointer to the IUCV message
*
* The function puts an incoming message on the input queue for later
* processing (by hvc_iucv_get_chars() / hvc_iucv_write()).
* If the tty has not yet been opened, the message is rejected.
*
* Locking: struct hvc_iucv_private->lock
*/
static void hvc_iucv_msg_pending(struct iucv_path *path,
struct iucv_message *msg)
{
struct hvc_iucv_private *priv = path->private;
struct iucv_tty_buffer *rb;
/* reject messages that exceed max size of iucv_tty_msg->datalen */
if (msg->length > MSG_SIZE(MSG_MAX_DATALEN)) {
iucv_message_reject(path, msg);
return;
}
spin_lock(&priv->lock);
/* reject messages if tty has not yet been opened */
if (priv->tty_state == TTY_CLOSED) {
iucv_message_reject(path, msg);
goto unlock_return;
}
/* allocate tty buffer to save iucv msg only */
rb = alloc_tty_buffer(0, GFP_ATOMIC);
if (!rb) {
iucv_message_reject(path, msg);
goto unlock_return; /* -ENOMEM */
}
rb->msg = *msg;
list_add_tail(&rb->list, &priv->tty_inqueue);
hvc_kick(); /* wake up hvc thread */
unlock_return:
spin_unlock(&priv->lock);
}
/**
* hvc_iucv_msg_complete() - IUCV handler to process message completion
* @path: Pending path (struct iucv_path)
* @msg: Pointer to the IUCV message
*
* The function is called upon completion of message delivery to remove the
* message from the outqueue. Additional delivery information can be found
* msg->audit: rejected messages (0x040000 (IPADRJCT)), and
* purged messages (0x010000 (IPADPGNR)).
*
* Locking: struct hvc_iucv_private->lock
*/
static void hvc_iucv_msg_complete(struct iucv_path *path,
struct iucv_message *msg)
{
struct hvc_iucv_private *priv = path->private;
struct iucv_tty_buffer *ent, *next;
LIST_HEAD(list_remove);
spin_lock(&priv->lock);
list_for_each_entry_safe(ent, next, &priv->tty_outqueue, list)
if (ent->msg.id == msg->id) {
list_move(&ent->list, &list_remove);
break;
}
wake_up(&priv->sndbuf_waitq);
spin_unlock(&priv->lock);
destroy_tty_buffer_list(&list_remove);
}
/**
* hvc_iucv_pm_freeze() - Freeze PM callback
* @dev: IUVC HVC terminal device
*
* Sever an established IUCV communication path and
* trigger a hang-up of the underlying HVC terminal.
*/
static int hvc_iucv_pm_freeze(struct device *dev)
{
struct hvc_iucv_private *priv = dev_get_drvdata(dev);
local_bh_disable();
hvc_iucv_hangup(priv);
local_bh_enable();
return 0;
}
/**
* hvc_iucv_pm_restore_thaw() - Thaw and restore PM callback
* @dev: IUVC HVC terminal device
*
* Wake up the HVC thread to trigger hang-up and respective
* HVC back-end notifier invocations.
*/
static int hvc_iucv_pm_restore_thaw(struct device *dev)
{
hvc_kick();
return 0;
}
/* HVC operations */
static const struct hv_ops hvc_iucv_ops = {
.get_chars = hvc_iucv_get_chars,
.put_chars = hvc_iucv_put_chars,
.notifier_add = hvc_iucv_notifier_add,
.notifier_del = hvc_iucv_notifier_del,
.notifier_hangup = hvc_iucv_notifier_hangup,
};
/* Suspend / resume device operations */
static const struct dev_pm_ops hvc_iucv_pm_ops = {
.freeze = hvc_iucv_pm_freeze,
.thaw = hvc_iucv_pm_restore_thaw,
.restore = hvc_iucv_pm_restore_thaw,
};
/* IUCV HVC device driver */
static struct device_driver hvc_iucv_driver = {
.name = KMSG_COMPONENT,
.bus = &iucv_bus,
.pm = &hvc_iucv_pm_ops,
};
/**
* hvc_iucv_alloc() - Allocates a new struct hvc_iucv_private instance
* @id: hvc_iucv_table index
* @is_console: Flag if the instance is used as Linux console
*
* This function allocates a new hvc_iucv_private structure and stores
* the instance in hvc_iucv_table at index @id.
* Returns 0 on success; otherwise non-zero.
*/
static int __init hvc_iucv_alloc(int id, unsigned int is_console)
{
struct hvc_iucv_private *priv;
char name[9];
int rc;
priv = kzalloc(sizeof(struct hvc_iucv_private), GFP_KERNEL);
if (!priv)
return -ENOMEM;
spin_lock_init(&priv->lock);
INIT_LIST_HEAD(&priv->tty_outqueue);
INIT_LIST_HEAD(&priv->tty_inqueue);
INIT_DELAYED_WORK(&priv->sndbuf_work, hvc_iucv_sndbuf_work);
init_waitqueue_head(&priv->sndbuf_waitq);
priv->sndbuf = (void *) get_zeroed_page(GFP_KERNEL);
if (!priv->sndbuf) {
kfree(priv);
return -ENOMEM;
}
/* set console flag */
priv->is_console = is_console;
/* allocate hvc device */
priv->hvc = hvc_alloc(HVC_IUCV_MAGIC + id, /* PAGE_SIZE */
HVC_IUCV_MAGIC + id, &hvc_iucv_ops, 256);
if (IS_ERR(priv->hvc)) {
rc = PTR_ERR(priv->hvc);
goto out_error_hvc;
}
/* notify HVC thread instead of using polling */
priv->hvc->irq_requested = 1;
/* setup iucv related information */
snprintf(name, 9, "lnxhvc%-2d", id);
memcpy(priv->srv_name, name, 8);
ASCEBC(priv->srv_name, 8);
/* create and setup device */
priv->dev = kzalloc(sizeof(*priv->dev), GFP_KERNEL);
if (!priv->dev) {
rc = -ENOMEM;
goto out_error_dev;
}
dev_set_name(priv->dev, "hvc_iucv%d", id);
dev_set_drvdata(priv->dev, priv);
priv->dev->bus = &iucv_bus;
priv->dev->parent = iucv_root;
priv->dev->driver = &hvc_iucv_driver;
priv->dev->release = (void (*)(struct device *)) kfree;
rc = device_register(priv->dev);
if (rc) {
put_device(priv->dev);
goto out_error_dev;
}
hvc_iucv_table[id] = priv;
return 0;
out_error_dev:
hvc_remove(priv->hvc);
out_error_hvc:
free_page((unsigned long) priv->sndbuf);
kfree(priv);
return rc;
}
/**
* hvc_iucv_destroy() - Destroy and free hvc_iucv_private instances
*/
static void __init hvc_iucv_destroy(struct hvc_iucv_private *priv)
{
hvc_remove(priv->hvc);
device_unregister(priv->dev);
free_page((unsigned long) priv->sndbuf);
kfree(priv);
}
/**
* hvc_iucv_parse_filter() - Parse filter for a single z/VM user ID
* @filter: String containing a comma-separated list of z/VM user IDs
*/
static const char *hvc_iucv_parse_filter(const char *filter, char *dest)
{
const char *nextdelim, *residual;
size_t len;
nextdelim = strchr(filter, ',');
if (nextdelim) {
len = nextdelim - filter;
residual = nextdelim + 1;
} else {
len = strlen(filter);
residual = filter + len;
}
if (len == 0)
return ERR_PTR(-EINVAL);
/* check for '\n' (if called from sysfs) */
if (filter[len - 1] == '\n')
len--;
if (len > 8)
return ERR_PTR(-EINVAL);
/* pad with blanks and save upper case version of user ID */
memset(dest, ' ', 8);
while (len--)
dest[len] = toupper(filter[len]);
return residual;
}
/**
* hvc_iucv_setup_filter() - Set up z/VM user ID filter
* @filter: String consisting of a comma-separated list of z/VM user IDs
*
* The function parses the @filter string and creates an array containing
* the list of z/VM user ID filter entries.
* Return code 0 means success, -EINVAL if the filter is syntactically
* incorrect, -ENOMEM if there was not enough memory to allocate the
* filter list array, or -ENOSPC if too many z/VM user IDs have been specified.
*/
static int hvc_iucv_setup_filter(const char *val)
{
const char *residual;
int err;
size_t size, count;
void *array, *old_filter;
count = strlen(val);
if (count == 0 || (count == 1 && val[0] == '\n')) {
size = 0;
array = NULL;
goto out_replace_filter; /* clear filter */
}
/* count user IDs in order to allocate sufficient memory */
size = 1;
residual = val;
while ((residual = strchr(residual, ',')) != NULL) {
residual++;
size++;
}
/* check if the specified list exceeds the filter limit */
if (size > MAX_VMID_FILTER)
return -ENOSPC;
array = kzalloc(size * 8, GFP_KERNEL);
if (!array)
return -ENOMEM;
count = size;
residual = val;
while (*residual && count) {
residual = hvc_iucv_parse_filter(residual,
array + ((size - count) * 8));
if (IS_ERR(residual)) {
err = PTR_ERR(residual);
kfree(array);
goto out_err;
}
count--;
}
out_replace_filter:
write_lock_bh(&hvc_iucv_filter_lock);
old_filter = hvc_iucv_filter;
hvc_iucv_filter_size = size;
hvc_iucv_filter = array;
write_unlock_bh(&hvc_iucv_filter_lock);
kfree(old_filter);
err = 0;
out_err:
return err;
}
/**
* param_set_vmidfilter() - Set z/VM user ID filter parameter
* @val: String consisting of a comma-separated list of z/VM user IDs
* @kp: Kernel parameter pointing to hvc_iucv_filter array
*
* The function sets up the z/VM user ID filter specified as comma-separated
* list of user IDs in @val.
* Note: If it is called early in the boot process, @val is stored and
* parsed later in hvc_iucv_init().
*/
static int param_set_vmidfilter(const char *val, struct kernel_param *kp)
{
int rc;
if (!MACHINE_IS_VM || !hvc_iucv_devices)
return -ENODEV;
if (!val)
return -EINVAL;
rc = 0;
if (slab_is_available())
rc = hvc_iucv_setup_filter(val);
else
hvc_iucv_filter_string = val; /* defer... */
return rc;
}
/**
* param_get_vmidfilter() - Get z/VM user ID filter
* @buffer: Buffer to store z/VM user ID filter,
* (buffer size assumption PAGE_SIZE)
* @kp: Kernel parameter pointing to the hvc_iucv_filter array
*
* The function stores the filter as a comma-separated list of z/VM user IDs
* in @buffer. Typically, sysfs routines call this function for attr show.
*/
static int param_get_vmidfilter(char *buffer, struct kernel_param *kp)
{
int rc;
size_t index, len;
void *start, *end;
if (!MACHINE_IS_VM || !hvc_iucv_devices)
return -ENODEV;
rc = 0;
read_lock_bh(&hvc_iucv_filter_lock);
for (index = 0; index < hvc_iucv_filter_size; index++) {
start = hvc_iucv_filter + (8 * index);
end = memchr(start, ' ', 8);
len = (end) ? end - start : 8;
memcpy(buffer + rc, start, len);
rc += len;
buffer[rc++] = ',';
}
read_unlock_bh(&hvc_iucv_filter_lock);
if (rc)
buffer[--rc] = '\0'; /* replace last comma and update rc */
return rc;
}
#define param_check_vmidfilter(name, p) __param_check(name, p, void)
/**
* hvc_iucv_init() - z/VM IUCV HVC device driver initialization
*/
static int __init hvc_iucv_init(void)
{
int rc;
unsigned int i;
if (!hvc_iucv_devices)
return -ENODEV;
if (!MACHINE_IS_VM) {
pr_notice("The z/VM IUCV HVC device driver cannot "
"be used without z/VM\n");
rc = -ENODEV;
goto out_error;
}
if (hvc_iucv_devices > MAX_HVC_IUCV_LINES) {
pr_err("%lu is not a valid value for the hvc_iucv= "
"kernel parameter\n", hvc_iucv_devices);
rc = -EINVAL;
goto out_error;
}
/* register IUCV HVC device driver */
rc = driver_register(&hvc_iucv_driver);
if (rc)
goto out_error;
/* parse hvc_iucv_allow string and create z/VM user ID filter list */
if (hvc_iucv_filter_string) {
rc = hvc_iucv_setup_filter(hvc_iucv_filter_string);
switch (rc) {
case 0:
break;
case -ENOMEM:
pr_err("Allocating memory failed with "
"reason code=%d\n", 3);
goto out_error;
case -EINVAL:
pr_err("hvc_iucv_allow= does not specify a valid "
"z/VM user ID list\n");
goto out_error;
case -ENOSPC:
pr_err("hvc_iucv_allow= specifies too many "
"z/VM user IDs\n");
goto out_error;
default:
goto out_error;
}
}
hvc_iucv_buffer_cache = kmem_cache_create(KMSG_COMPONENT,
sizeof(struct iucv_tty_buffer),
0, 0, NULL);
if (!hvc_iucv_buffer_cache) {
pr_err("Allocating memory failed with reason code=%d\n", 1);
rc = -ENOMEM;
goto out_error;
}
hvc_iucv_mempool = mempool_create_slab_pool(MEMPOOL_MIN_NR,
hvc_iucv_buffer_cache);
if (!hvc_iucv_mempool) {
pr_err("Allocating memory failed with reason code=%d\n", 2);
kmem_cache_destroy(hvc_iucv_buffer_cache);
rc = -ENOMEM;
goto out_error;
}
/* register the first terminal device as console
* (must be done before allocating hvc terminal devices) */
rc = hvc_instantiate(HVC_IUCV_MAGIC, IUCV_HVC_CON_IDX, &hvc_iucv_ops);
if (rc) {
pr_err("Registering HVC terminal device as "
"Linux console failed\n");
goto out_error_memory;
}
/* allocate hvc_iucv_private structs */
for (i = 0; i < hvc_iucv_devices; i++) {
rc = hvc_iucv_alloc(i, (i == IUCV_HVC_CON_IDX) ? 1 : 0);
if (rc) {
pr_err("Creating a new HVC terminal device "
"failed with error code=%d\n", rc);
goto out_error_hvc;
}
}
/* register IUCV callback handler */
rc = iucv_register(&hvc_iucv_handler, 0);
if (rc) {
pr_err("Registering IUCV handlers failed with error code=%d\n",
rc);
goto out_error_iucv;
}
return 0;
out_error_iucv:
iucv_unregister(&hvc_iucv_handler, 0);
out_error_hvc:
for (i = 0; i < hvc_iucv_devices; i++)
if (hvc_iucv_table[i])
hvc_iucv_destroy(hvc_iucv_table[i]);
out_error_memory:
mempool_destroy(hvc_iucv_mempool);
kmem_cache_destroy(hvc_iucv_buffer_cache);
out_error:
if (hvc_iucv_filter)
kfree(hvc_iucv_filter);
hvc_iucv_devices = 0; /* ensure that we do not provide any device */
return rc;
}
/**
* hvc_iucv_config() - Parsing of hvc_iucv= kernel command line parameter
* @val: Parameter value (numeric)
*/
static int __init hvc_iucv_config(char *val)
{
return strict_strtoul(val, 10, &hvc_iucv_devices);
}
device_initcall(hvc_iucv_init);
__setup("hvc_iucv=", hvc_iucv_config);
core_param(hvc_iucv_allow, hvc_iucv_filter, vmidfilter, 0640);