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533 lines
13 KiB
533 lines
13 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Character device driver for reading z/VM *MONITOR service records. |
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* |
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* Copyright IBM Corp. 2004, 2009 |
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* |
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* Author: Gerald Schaefer <[email protected]> |
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*/ |
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#define KMSG_COMPONENT "monreader" |
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#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt |
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#include <linux/module.h> |
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#include <linux/moduleparam.h> |
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#include <linux/init.h> |
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#include <linux/errno.h> |
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#include <linux/types.h> |
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#include <linux/kernel.h> |
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#include <linux/miscdevice.h> |
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#include <linux/ctype.h> |
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#include <linux/spinlock.h> |
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#include <linux/interrupt.h> |
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#include <linux/poll.h> |
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#include <linux/slab.h> |
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#include <net/iucv/iucv.h> |
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#include <linux/uaccess.h> |
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#include <asm/ebcdic.h> |
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#include <asm/extmem.h> |
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#define MON_COLLECT_SAMPLE 0x80 |
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#define MON_COLLECT_EVENT 0x40 |
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#define MON_SERVICE "*MONITOR" |
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#define MON_IN_USE 0x01 |
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#define MON_MSGLIM 255 |
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static char mon_dcss_name[9] = "MONDCSS\0"; |
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struct mon_msg { |
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u32 pos; |
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u32 mca_offset; |
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struct iucv_message msg; |
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char msglim_reached; |
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char replied_msglim; |
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}; |
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struct mon_private { |
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struct iucv_path *path; |
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struct mon_msg *msg_array[MON_MSGLIM]; |
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unsigned int write_index; |
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unsigned int read_index; |
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atomic_t msglim_count; |
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atomic_t read_ready; |
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atomic_t iucv_connected; |
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atomic_t iucv_severed; |
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}; |
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static unsigned long mon_in_use = 0; |
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static unsigned long mon_dcss_start; |
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static unsigned long mon_dcss_end; |
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static DECLARE_WAIT_QUEUE_HEAD(mon_read_wait_queue); |
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static DECLARE_WAIT_QUEUE_HEAD(mon_conn_wait_queue); |
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static u8 user_data_connect[16] = { |
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/* Version code, must be 0x01 for shared mode */ |
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0x01, |
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/* what to collect */ |
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MON_COLLECT_SAMPLE | MON_COLLECT_EVENT, |
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/* DCSS name in EBCDIC, 8 bytes padded with blanks */ |
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, |
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, |
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}; |
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static u8 user_data_sever[16] = { |
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, |
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, |
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}; |
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/****************************************************************************** |
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* helper functions * |
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*****************************************************************************/ |
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/* |
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* Create the 8 bytes EBCDIC DCSS segment name from |
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* an ASCII name, incl. padding |
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*/ |
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static void dcss_mkname(char *ascii_name, char *ebcdic_name) |
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{ |
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int i; |
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for (i = 0; i < 8; i++) { |
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if (ascii_name[i] == '\0') |
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break; |
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ebcdic_name[i] = toupper(ascii_name[i]); |
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} |
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for (; i < 8; i++) |
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ebcdic_name[i] = ' '; |
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ASCEBC(ebcdic_name, 8); |
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} |
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static inline unsigned long mon_mca_start(struct mon_msg *monmsg) |
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{ |
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return *(u32 *) &monmsg->msg.rmmsg; |
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} |
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static inline unsigned long mon_mca_end(struct mon_msg *monmsg) |
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{ |
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return *(u32 *) &monmsg->msg.rmmsg[4]; |
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} |
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static inline u8 mon_mca_type(struct mon_msg *monmsg, u8 index) |
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{ |
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return *((u8 *) mon_mca_start(monmsg) + monmsg->mca_offset + index); |
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} |
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static inline u32 mon_mca_size(struct mon_msg *monmsg) |
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{ |
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return mon_mca_end(monmsg) - mon_mca_start(monmsg) + 1; |
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} |
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static inline u32 mon_rec_start(struct mon_msg *monmsg) |
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{ |
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return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 4)); |
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} |
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static inline u32 mon_rec_end(struct mon_msg *monmsg) |
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{ |
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return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 8)); |
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} |
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static int mon_check_mca(struct mon_msg *monmsg) |
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{ |
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if ((mon_rec_end(monmsg) <= mon_rec_start(monmsg)) || |
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(mon_rec_start(monmsg) < mon_dcss_start) || |
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(mon_rec_end(monmsg) > mon_dcss_end) || |
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(mon_mca_type(monmsg, 0) == 0) || |
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(mon_mca_size(monmsg) % 12 != 0) || |
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(mon_mca_end(monmsg) <= mon_mca_start(monmsg)) || |
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(mon_mca_end(monmsg) > mon_dcss_end) || |
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(mon_mca_start(monmsg) < mon_dcss_start) || |
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((mon_mca_type(monmsg, 1) == 0) && (mon_mca_type(monmsg, 2) == 0))) |
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return -EINVAL; |
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return 0; |
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} |
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static int mon_send_reply(struct mon_msg *monmsg, |
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struct mon_private *monpriv) |
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{ |
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int rc; |
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rc = iucv_message_reply(monpriv->path, &monmsg->msg, |
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IUCV_IPRMDATA, NULL, 0); |
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atomic_dec(&monpriv->msglim_count); |
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if (likely(!monmsg->msglim_reached)) { |
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monmsg->pos = 0; |
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monmsg->mca_offset = 0; |
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monpriv->read_index = (monpriv->read_index + 1) % |
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MON_MSGLIM; |
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atomic_dec(&monpriv->read_ready); |
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} else |
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monmsg->replied_msglim = 1; |
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if (rc) { |
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pr_err("Reading monitor data failed with rc=%i\n", rc); |
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return -EIO; |
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} |
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return 0; |
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} |
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static void mon_free_mem(struct mon_private *monpriv) |
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{ |
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int i; |
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for (i = 0; i < MON_MSGLIM; i++) |
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kfree(monpriv->msg_array[i]); |
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kfree(monpriv); |
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} |
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static struct mon_private *mon_alloc_mem(void) |
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{ |
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int i; |
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struct mon_private *monpriv; |
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monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL); |
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if (!monpriv) |
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return NULL; |
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for (i = 0; i < MON_MSGLIM; i++) { |
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monpriv->msg_array[i] = kzalloc(sizeof(struct mon_msg), |
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GFP_KERNEL); |
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if (!monpriv->msg_array[i]) { |
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mon_free_mem(monpriv); |
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return NULL; |
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} |
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} |
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return monpriv; |
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} |
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static inline void mon_next_mca(struct mon_msg *monmsg) |
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{ |
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if (likely((mon_mca_size(monmsg) - monmsg->mca_offset) == 12)) |
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return; |
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monmsg->mca_offset += 12; |
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monmsg->pos = 0; |
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} |
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static struct mon_msg *mon_next_message(struct mon_private *monpriv) |
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{ |
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struct mon_msg *monmsg; |
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if (!atomic_read(&monpriv->read_ready)) |
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return NULL; |
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monmsg = monpriv->msg_array[monpriv->read_index]; |
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if (unlikely(monmsg->replied_msglim)) { |
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monmsg->replied_msglim = 0; |
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monmsg->msglim_reached = 0; |
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monmsg->pos = 0; |
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monmsg->mca_offset = 0; |
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monpriv->read_index = (monpriv->read_index + 1) % |
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MON_MSGLIM; |
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atomic_dec(&monpriv->read_ready); |
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return ERR_PTR(-EOVERFLOW); |
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} |
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return monmsg; |
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} |
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/****************************************************************************** |
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* IUCV handler * |
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*****************************************************************************/ |
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static void mon_iucv_path_complete(struct iucv_path *path, u8 *ipuser) |
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{ |
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struct mon_private *monpriv = path->private; |
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atomic_set(&monpriv->iucv_connected, 1); |
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wake_up(&mon_conn_wait_queue); |
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} |
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static void mon_iucv_path_severed(struct iucv_path *path, u8 *ipuser) |
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{ |
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struct mon_private *monpriv = path->private; |
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pr_err("z/VM *MONITOR system service disconnected with rc=%i\n", |
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ipuser[0]); |
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iucv_path_sever(path, NULL); |
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atomic_set(&monpriv->iucv_severed, 1); |
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wake_up(&mon_conn_wait_queue); |
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wake_up_interruptible(&mon_read_wait_queue); |
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} |
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static void mon_iucv_message_pending(struct iucv_path *path, |
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struct iucv_message *msg) |
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{ |
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struct mon_private *monpriv = path->private; |
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memcpy(&monpriv->msg_array[monpriv->write_index]->msg, |
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msg, sizeof(*msg)); |
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if (atomic_inc_return(&monpriv->msglim_count) == MON_MSGLIM) { |
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pr_warn("The read queue for monitor data is full\n"); |
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monpriv->msg_array[monpriv->write_index]->msglim_reached = 1; |
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} |
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monpriv->write_index = (monpriv->write_index + 1) % MON_MSGLIM; |
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atomic_inc(&monpriv->read_ready); |
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wake_up_interruptible(&mon_read_wait_queue); |
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} |
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static struct iucv_handler monreader_iucv_handler = { |
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.path_complete = mon_iucv_path_complete, |
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.path_severed = mon_iucv_path_severed, |
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.message_pending = mon_iucv_message_pending, |
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}; |
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/****************************************************************************** |
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* file operations * |
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*****************************************************************************/ |
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static int mon_open(struct inode *inode, struct file *filp) |
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{ |
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struct mon_private *monpriv; |
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int rc; |
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/* |
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* only one user allowed |
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*/ |
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rc = -EBUSY; |
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if (test_and_set_bit(MON_IN_USE, &mon_in_use)) |
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goto out; |
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rc = -ENOMEM; |
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monpriv = mon_alloc_mem(); |
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if (!monpriv) |
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goto out_use; |
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/* |
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* Connect to *MONITOR service |
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*/ |
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monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL); |
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if (!monpriv->path) |
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goto out_priv; |
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rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler, |
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MON_SERVICE, NULL, user_data_connect, monpriv); |
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if (rc) { |
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pr_err("Connecting to the z/VM *MONITOR system service " |
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"failed with rc=%i\n", rc); |
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rc = -EIO; |
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goto out_path; |
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} |
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/* |
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* Wait for connection confirmation |
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*/ |
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wait_event(mon_conn_wait_queue, |
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atomic_read(&monpriv->iucv_connected) || |
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atomic_read(&monpriv->iucv_severed)); |
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if (atomic_read(&monpriv->iucv_severed)) { |
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atomic_set(&monpriv->iucv_severed, 0); |
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atomic_set(&monpriv->iucv_connected, 0); |
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rc = -EIO; |
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goto out_path; |
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} |
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filp->private_data = monpriv; |
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return nonseekable_open(inode, filp); |
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out_path: |
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iucv_path_free(monpriv->path); |
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out_priv: |
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mon_free_mem(monpriv); |
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out_use: |
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clear_bit(MON_IN_USE, &mon_in_use); |
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out: |
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return rc; |
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} |
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static int mon_close(struct inode *inode, struct file *filp) |
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{ |
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int rc, i; |
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struct mon_private *monpriv = filp->private_data; |
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/* |
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* Close IUCV connection and unregister |
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*/ |
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if (monpriv->path) { |
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rc = iucv_path_sever(monpriv->path, user_data_sever); |
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if (rc) |
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pr_warn("Disconnecting the z/VM *MONITOR system service failed with rc=%i\n", |
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rc); |
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iucv_path_free(monpriv->path); |
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} |
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atomic_set(&monpriv->iucv_severed, 0); |
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atomic_set(&monpriv->iucv_connected, 0); |
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atomic_set(&monpriv->read_ready, 0); |
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atomic_set(&monpriv->msglim_count, 0); |
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monpriv->write_index = 0; |
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monpriv->read_index = 0; |
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for (i = 0; i < MON_MSGLIM; i++) |
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kfree(monpriv->msg_array[i]); |
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kfree(monpriv); |
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clear_bit(MON_IN_USE, &mon_in_use); |
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return 0; |
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} |
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static ssize_t mon_read(struct file *filp, char __user *data, |
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size_t count, loff_t *ppos) |
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{ |
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struct mon_private *monpriv = filp->private_data; |
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struct mon_msg *monmsg; |
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int ret; |
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u32 mce_start; |
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monmsg = mon_next_message(monpriv); |
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if (IS_ERR(monmsg)) |
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return PTR_ERR(monmsg); |
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if (!monmsg) { |
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if (filp->f_flags & O_NONBLOCK) |
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return -EAGAIN; |
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ret = wait_event_interruptible(mon_read_wait_queue, |
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atomic_read(&monpriv->read_ready) || |
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atomic_read(&monpriv->iucv_severed)); |
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if (ret) |
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return ret; |
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if (unlikely(atomic_read(&monpriv->iucv_severed))) |
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return -EIO; |
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monmsg = monpriv->msg_array[monpriv->read_index]; |
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} |
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if (!monmsg->pos) |
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monmsg->pos = mon_mca_start(monmsg) + monmsg->mca_offset; |
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if (mon_check_mca(monmsg)) |
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goto reply; |
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/* read monitor control element (12 bytes) first */ |
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mce_start = mon_mca_start(monmsg) + monmsg->mca_offset; |
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if ((monmsg->pos >= mce_start) && (monmsg->pos < mce_start + 12)) { |
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count = min(count, (size_t) mce_start + 12 - monmsg->pos); |
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ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos, |
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count); |
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if (ret) |
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return -EFAULT; |
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monmsg->pos += count; |
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if (monmsg->pos == mce_start + 12) |
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monmsg->pos = mon_rec_start(monmsg); |
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goto out_copy; |
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} |
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/* read records */ |
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if (monmsg->pos <= mon_rec_end(monmsg)) { |
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count = min(count, (size_t) mon_rec_end(monmsg) - monmsg->pos |
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+ 1); |
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ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos, |
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count); |
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if (ret) |
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return -EFAULT; |
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monmsg->pos += count; |
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if (monmsg->pos > mon_rec_end(monmsg)) |
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mon_next_mca(monmsg); |
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goto out_copy; |
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} |
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reply: |
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ret = mon_send_reply(monmsg, monpriv); |
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return ret; |
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out_copy: |
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*ppos += count; |
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return count; |
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} |
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static __poll_t mon_poll(struct file *filp, struct poll_table_struct *p) |
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{ |
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struct mon_private *monpriv = filp->private_data; |
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poll_wait(filp, &mon_read_wait_queue, p); |
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if (unlikely(atomic_read(&monpriv->iucv_severed))) |
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return EPOLLERR; |
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if (atomic_read(&monpriv->read_ready)) |
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return EPOLLIN | EPOLLRDNORM; |
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return 0; |
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} |
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static const struct file_operations mon_fops = { |
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.owner = THIS_MODULE, |
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.open = &mon_open, |
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.release = &mon_close, |
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.read = &mon_read, |
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.poll = &mon_poll, |
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.llseek = noop_llseek, |
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}; |
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static struct miscdevice mon_dev = { |
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.name = "monreader", |
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.fops = &mon_fops, |
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.minor = MISC_DYNAMIC_MINOR, |
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}; |
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/****************************************************************************** |
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* module init/exit * |
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*****************************************************************************/ |
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static int __init mon_init(void) |
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{ |
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int rc; |
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if (!MACHINE_IS_VM) { |
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pr_err("The z/VM *MONITOR record device driver cannot be " |
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"loaded without z/VM\n"); |
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return -ENODEV; |
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} |
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/* |
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* Register with IUCV and connect to *MONITOR service |
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*/ |
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rc = iucv_register(&monreader_iucv_handler, 1); |
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if (rc) { |
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pr_err("The z/VM *MONITOR record device driver failed to " |
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"register with IUCV\n"); |
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return rc; |
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} |
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rc = segment_type(mon_dcss_name); |
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if (rc < 0) { |
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segment_warning(rc, mon_dcss_name); |
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goto out_iucv; |
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} |
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if (rc != SEG_TYPE_SC) { |
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pr_err("The specified *MONITOR DCSS %s does not have the " |
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"required type SC\n", mon_dcss_name); |
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rc = -EINVAL; |
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goto out_iucv; |
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} |
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rc = segment_load(mon_dcss_name, SEGMENT_SHARED, |
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&mon_dcss_start, &mon_dcss_end); |
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if (rc < 0) { |
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segment_warning(rc, mon_dcss_name); |
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rc = -EINVAL; |
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goto out_iucv; |
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} |
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dcss_mkname(mon_dcss_name, &user_data_connect[8]); |
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/* |
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* misc_register() has to be the last action in module_init(), because |
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* file operations will be available right after this. |
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*/ |
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rc = misc_register(&mon_dev); |
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if (rc < 0 ) |
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goto out; |
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return 0; |
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out: |
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segment_unload(mon_dcss_name); |
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out_iucv: |
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iucv_unregister(&monreader_iucv_handler, 1); |
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return rc; |
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} |
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static void __exit mon_exit(void) |
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{ |
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segment_unload(mon_dcss_name); |
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misc_deregister(&mon_dev); |
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iucv_unregister(&monreader_iucv_handler, 1); |
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return; |
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} |
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module_init(mon_init); |
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module_exit(mon_exit); |
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module_param_string(mondcss, mon_dcss_name, 9, 0444); |
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MODULE_PARM_DESC(mondcss, "Name of DCSS segment to be used for *MONITOR " |
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"service, max. 8 chars. Default is MONDCSS"); |
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MODULE_AUTHOR("Gerald Schaefer <[email protected]>"); |
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MODULE_DESCRIPTION("Character device driver for reading z/VM " |
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"monitor service records."); |
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MODULE_LICENSE("GPL");
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