1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Channel report handling code |
4 | * |
5 | * Copyright IBM Corp. 2000, 2009 |
6 | * Author(s): Ingo Adlung <adlung@de.ibm.com>, |
7 | * Martin Schwidefsky <schwidefsky@de.ibm.com>, |
8 | * Cornelia Huck <cornelia.huck@de.ibm.com>, |
9 | */ |
10 | |
11 | #include <linux/mutex.h> |
12 | #include <linux/kthread.h> |
13 | #include <linux/init.h> |
14 | #include <linux/wait.h> |
15 | #include <asm/ctlreg.h> |
16 | #include <asm/crw.h> |
17 | #include "ioasm.h" |
18 | |
19 | static DEFINE_MUTEX(crw_handler_mutex); |
20 | static crw_handler_t crw_handlers[NR_RSCS]; |
21 | static atomic_t crw_nr_req = ATOMIC_INIT(0); |
22 | static DECLARE_WAIT_QUEUE_HEAD(crw_handler_wait_q); |
23 | |
24 | /** |
25 | * crw_register_handler() - register a channel report word handler |
26 | * @rsc: reporting source code to handle |
27 | * @handler: handler to be registered |
28 | * |
29 | * Returns %0 on success and a negative error value otherwise. |
30 | */ |
31 | int crw_register_handler(int rsc, crw_handler_t handler) |
32 | { |
33 | int rc = 0; |
34 | |
35 | if ((rsc < 0) || (rsc >= NR_RSCS)) |
36 | return -EINVAL; |
37 | mutex_lock(&crw_handler_mutex); |
38 | if (crw_handlers[rsc]) |
39 | rc = -EBUSY; |
40 | else |
41 | crw_handlers[rsc] = handler; |
42 | mutex_unlock(lock: &crw_handler_mutex); |
43 | return rc; |
44 | } |
45 | |
46 | /** |
47 | * crw_unregister_handler() - unregister a channel report word handler |
48 | * @rsc: reporting source code to handle |
49 | */ |
50 | void crw_unregister_handler(int rsc) |
51 | { |
52 | if ((rsc < 0) || (rsc >= NR_RSCS)) |
53 | return; |
54 | mutex_lock(&crw_handler_mutex); |
55 | crw_handlers[rsc] = NULL; |
56 | mutex_unlock(lock: &crw_handler_mutex); |
57 | } |
58 | |
59 | /* |
60 | * Retrieve CRWs and call function to handle event. |
61 | */ |
62 | static int crw_collect_info(void *unused) |
63 | { |
64 | struct crw crw[2]; |
65 | int ccode, signal; |
66 | unsigned int chain; |
67 | |
68 | repeat: |
69 | signal = wait_event_interruptible(crw_handler_wait_q, |
70 | atomic_read(&crw_nr_req) > 0); |
71 | if (unlikely(signal)) |
72 | atomic_inc(v: &crw_nr_req); |
73 | chain = 0; |
74 | while (1) { |
75 | crw_handler_t handler; |
76 | |
77 | if (unlikely(chain > 1)) { |
78 | struct crw tmp_crw; |
79 | |
80 | printk(KERN_WARNING"%s: Code does not support more " |
81 | "than two chained crws; please report to " |
82 | "linux390@de.ibm.com!\n" , __func__); |
83 | ccode = stcrw(crw: &tmp_crw); |
84 | printk(KERN_WARNING"%s: crw reports slct=%d, oflw=%d, " |
85 | "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n" , |
86 | __func__, tmp_crw.slct, tmp_crw.oflw, |
87 | tmp_crw.chn, tmp_crw.rsc, tmp_crw.anc, |
88 | tmp_crw.erc, tmp_crw.rsid); |
89 | printk(KERN_WARNING"%s: This was crw number %x in the " |
90 | "chain\n" , __func__, chain); |
91 | if (ccode != 0) |
92 | break; |
93 | chain = tmp_crw.chn ? chain + 1 : 0; |
94 | continue; |
95 | } |
96 | ccode = stcrw(crw: &crw[chain]); |
97 | if (ccode != 0) |
98 | break; |
99 | printk(KERN_DEBUG "crw_info : CRW reports slct=%d, oflw=%d, " |
100 | "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n" , |
101 | crw[chain].slct, crw[chain].oflw, crw[chain].chn, |
102 | crw[chain].rsc, crw[chain].anc, crw[chain].erc, |
103 | crw[chain].rsid); |
104 | /* Check for overflows. */ |
105 | if (crw[chain].oflw) { |
106 | int i; |
107 | |
108 | pr_debug("%s: crw overflow detected!\n" , __func__); |
109 | mutex_lock(&crw_handler_mutex); |
110 | for (i = 0; i < NR_RSCS; i++) { |
111 | if (crw_handlers[i]) |
112 | crw_handlers[i](NULL, NULL, 1); |
113 | } |
114 | mutex_unlock(lock: &crw_handler_mutex); |
115 | chain = 0; |
116 | continue; |
117 | } |
118 | if (crw[0].chn && !chain) { |
119 | chain++; |
120 | continue; |
121 | } |
122 | mutex_lock(&crw_handler_mutex); |
123 | handler = crw_handlers[crw[chain].rsc]; |
124 | if (handler) |
125 | handler(&crw[0], chain ? &crw[1] : NULL, 0); |
126 | mutex_unlock(lock: &crw_handler_mutex); |
127 | /* chain is always 0 or 1 here. */ |
128 | chain = crw[chain].chn ? chain + 1 : 0; |
129 | } |
130 | if (atomic_dec_and_test(v: &crw_nr_req)) |
131 | wake_up(&crw_handler_wait_q); |
132 | goto repeat; |
133 | return 0; |
134 | } |
135 | |
136 | void crw_handle_channel_report(void) |
137 | { |
138 | atomic_inc(v: &crw_nr_req); |
139 | wake_up(&crw_handler_wait_q); |
140 | } |
141 | |
142 | void crw_wait_for_channel_report(void) |
143 | { |
144 | crw_handle_channel_report(); |
145 | wait_event(crw_handler_wait_q, atomic_read(&crw_nr_req) == 0); |
146 | } |
147 | |
148 | /* |
149 | * Machine checks for the channel subsystem must be enabled |
150 | * after the channel subsystem is initialized |
151 | */ |
152 | static int __init crw_machine_check_init(void) |
153 | { |
154 | struct task_struct *task; |
155 | |
156 | task = kthread_run(crw_collect_info, NULL, "kmcheck" ); |
157 | if (IS_ERR(ptr: task)) |
158 | return PTR_ERR(ptr: task); |
159 | system_ctl_set_bit(14, CR14_CHANNEL_REPORT_SUBMASK_BIT); |
160 | return 0; |
161 | } |
162 | device_initcall(crw_machine_check_init); |
163 | |