cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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smsgiucv.c (4151B)

      1// SPDX-License-Identifier: GPL-2.0+
      2/*
      3 * IUCV special message driver
      4 *
      5 * Copyright IBM Corp. 2003, 2009
      6 *
      7 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
      8 */
      9
     10#include <linux/module.h>
     11#include <linux/init.h>
     12#include <linux/errno.h>
     13#include <linux/device.h>
     14#include <linux/slab.h>
     15#include <net/iucv/iucv.h>
     16#include <asm/cpcmd.h>
     17#include <asm/ebcdic.h>
     18#include "smsgiucv.h"
     19
     20struct smsg_callback {
     21	struct list_head list;
     22	const char *prefix;
     23	int len;
     24	void (*callback)(const char *from, char *str);
     25};
     26
     27MODULE_AUTHOR
     28   ("(C) 2003 IBM Corporation by Martin Schwidefsky (schwidefsky@de.ibm.com)");
     29MODULE_DESCRIPTION ("Linux for S/390 IUCV special message driver");
     30
     31static struct iucv_path *smsg_path;
     32
     33static DEFINE_SPINLOCK(smsg_list_lock);
     34static LIST_HEAD(smsg_list);
     35
     36static int smsg_path_pending(struct iucv_path *, u8 *, u8 *);
     37static void smsg_message_pending(struct iucv_path *, struct iucv_message *);
     38
     39static struct iucv_handler smsg_handler = {
     40	.path_pending	 = smsg_path_pending,
     41	.message_pending = smsg_message_pending,
     42};
     43
     44static int smsg_path_pending(struct iucv_path *path, u8 *ipvmid, u8 *ipuser)
     45{
     46	if (strncmp(ipvmid, "*MSG    ", 8) != 0)
     47		return -EINVAL;
     48	/* Path pending from *MSG. */
     49	return iucv_path_accept(path, &smsg_handler, "SMSGIUCV        ", NULL);
     50}
     51
     52static void smsg_message_pending(struct iucv_path *path,
     53				 struct iucv_message *msg)
     54{
     55	struct smsg_callback *cb;
     56	unsigned char *buffer;
     57	unsigned char sender[9];
     58	int rc, i;
     59
     60	buffer = kmalloc(msg->length + 1, GFP_ATOMIC | GFP_DMA);
     61	if (!buffer) {
     62		iucv_message_reject(path, msg);
     63		return;
     64	}
     65	rc = iucv_message_receive(path, msg, 0, buffer, msg->length, NULL);
     66	if (rc == 0) {
     67		buffer[msg->length] = 0;
     68		EBCASC(buffer, msg->length);
     69		memcpy(sender, buffer, 8);
     70		sender[8] = 0;
     71		/* Remove trailing whitespace from the sender name. */
     72		for (i = 7; i >= 0; i--) {
     73			if (sender[i] != ' ' && sender[i] != '\t')
     74				break;
     75			sender[i] = 0;
     76		}
     77		spin_lock(&smsg_list_lock);
     78		list_for_each_entry(cb, &smsg_list, list)
     79			if (strncmp(buffer + 8, cb->prefix, cb->len) == 0) {
     80				cb->callback(sender, buffer + 8);
     81				break;
     82			}
     83		spin_unlock(&smsg_list_lock);
     84	}
     85	kfree(buffer);
     86}
     87
     88int smsg_register_callback(const char *prefix,
     89			   void (*callback)(const char *from, char *str))
     90{
     91	struct smsg_callback *cb;
     92
     93	cb = kmalloc(sizeof(struct smsg_callback), GFP_KERNEL);
     94	if (!cb)
     95		return -ENOMEM;
     96	cb->prefix = prefix;
     97	cb->len = strlen(prefix);
     98	cb->callback = callback;
     99	spin_lock_bh(&smsg_list_lock);
    100	list_add_tail(&cb->list, &smsg_list);
    101	spin_unlock_bh(&smsg_list_lock);
    102	return 0;
    103}
    104
    105void smsg_unregister_callback(const char *prefix,
    106			      void (*callback)(const char *from,
    107					       char *str))
    108{
    109	struct smsg_callback *cb, *tmp;
    110
    111	spin_lock_bh(&smsg_list_lock);
    112	cb = NULL;
    113	list_for_each_entry(tmp, &smsg_list, list)
    114		if (tmp->callback == callback &&
    115		    strcmp(tmp->prefix, prefix) == 0) {
    116			cb = tmp;
    117			list_del(&cb->list);
    118			break;
    119		}
    120	spin_unlock_bh(&smsg_list_lock);
    121	kfree(cb);
    122}
    123
    124static struct device_driver smsg_driver = {
    125	.owner = THIS_MODULE,
    126	.name = SMSGIUCV_DRV_NAME,
    127	.bus  = &iucv_bus,
    128};
    129
    130static void __exit smsg_exit(void)
    131{
    132	cpcmd("SET SMSG OFF", NULL, 0, NULL);
    133	iucv_unregister(&smsg_handler, 1);
    134	driver_unregister(&smsg_driver);
    135}
    136
    137static int __init smsg_init(void)
    138{
    139	int rc;
    140
    141	if (!MACHINE_IS_VM) {
    142		rc = -EPROTONOSUPPORT;
    143		goto out;
    144	}
    145	rc = driver_register(&smsg_driver);
    146	if (rc != 0)
    147		goto out;
    148	rc = iucv_register(&smsg_handler, 1);
    149	if (rc)
    150		goto out_driver;
    151	smsg_path = iucv_path_alloc(255, 0, GFP_KERNEL);
    152	if (!smsg_path) {
    153		rc = -ENOMEM;
    154		goto out_register;
    155	}
    156	rc = iucv_path_connect(smsg_path, &smsg_handler, "*MSG    ",
    157			       NULL, NULL, NULL);
    158	if (rc)
    159		goto out_free_path;
    160
    161	cpcmd("SET SMSG IUCV", NULL, 0, NULL);
    162	return 0;
    163
    164out_free_path:
    165	iucv_path_free(smsg_path);
    166	smsg_path = NULL;
    167out_register:
    168	iucv_unregister(&smsg_handler, 1);
    169out_driver:
    170	driver_unregister(&smsg_driver);
    171out:
    172	return rc;
    173}
    174
    175module_init(smsg_init);
    176module_exit(smsg_exit);
    177MODULE_LICENSE("GPL");
    178
    179EXPORT_SYMBOL(smsg_register_callback);
    180EXPORT_SYMBOL(smsg_unregister_callback);