1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * S390 version
4 * Copyright IBM Corp. 1999, 2007
5 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
6 * Christian Borntraeger (cborntra@de.ibm.com),
7 */
8
9 #define KMSG_COMPONENT "cpcmd"
10 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
11
12 #include <linux/kernel.h>
13 #include <linux/export.h>
14 #include <linux/slab.h>
15 #include <linux/spinlock.h>
16 #include <linux/stddef.h>
17 #include <linux/string.h>
18 #include <linux/mm.h>
19 #include <linux/io.h>
20 #include <asm/diag.h>
21 #include <asm/ebcdic.h>
22 #include <asm/cpcmd.h>
23
24 static DEFINE_SPINLOCK(cpcmd_lock);
25 static char cpcmd_buf[241];
26
27 static int diag8_noresponse(int cmdlen)
28 {
29 asm volatile(
30 " diag %[rx],%[ry],0x8\n"
31 : [ry] "+&d" (cmdlen)
32 : [rx] "d" (__pa(cpcmd_buf))
33 : "cc");
34 return cmdlen;
35 }
36
37 static int diag8_response(int cmdlen, char *response, int *rlen)
38 {
39 union register_pair rx, ry;
40 int cc;
41
42 rx.even = __pa(cpcmd_buf);
43 rx.odd = __pa(response);
44 ry.even = cmdlen | 0x40000000L;
45 ry.odd = *rlen;
46 asm volatile(
47 " diag %[rx],%[ry],0x8\n"
48 " ipm %[cc]\n"
49 " srl %[cc],28\n"
50 : [cc] "=&d" (cc), [ry] "+&d" (ry.pair)
51 : [rx] "d" (rx.pair)
52 : "cc");
53 if (cc)
54 *rlen += ry.odd;
55 else
56 *rlen = ry.odd;
57 return ry.even;
58 }
59
60 /*
61 * __cpcmd has some restrictions over cpcmd
62 * - __cpcmd is unlocked and therefore not SMP-safe
63 */
64 int __cpcmd(const char *cmd, char *response, int rlen, int *response_code)
65 {
66 int cmdlen;
67 int rc;
68 int response_len;
69
70 cmdlen = strlen(cmd);
71 BUG_ON(cmdlen > 240);
72 memcpy(cpcmd_buf, cmd, cmdlen);
73 ASCEBC(cpcmd_buf, cmdlen);
74
75 diag_stat_inc(DIAG_STAT_X008);
76 if (response) {
77 memset(response, 0, rlen);
78 response_len = rlen;
79 rc = diag8_response(cmdlen, response, &rlen);
80 EBCASC(response, response_len);
81 } else {
82 rc = diag8_noresponse(cmdlen);
83 }
84 if (response_code)
85 *response_code = rc;
86 return rlen;
87 }
88 EXPORT_SYMBOL(__cpcmd);
89
90 int cpcmd(const char *cmd, char *response, int rlen, int *response_code)
91 {
92 unsigned long flags;
93 char *lowbuf;
94 int len;
95
96 if (is_vmalloc_or_module_addr(response)) {
97 lowbuf = kmalloc(rlen, GFP_KERNEL);
98 if (!lowbuf) {
99 pr_warn("The cpcmd kernel function failed to allocate a response buffer\n");
100 return -ENOMEM;
101 }
102 spin_lock_irqsave(&cpcmd_lock, flags);
103 len = __cpcmd(cmd, lowbuf, rlen, response_code);
104 spin_unlock_irqrestore(&cpcmd_lock, flags);
105 memcpy(response, lowbuf, rlen);
106 kfree(lowbuf);
107 } else {
108 spin_lock_irqsave(&cpcmd_lock, flags);
109 len = __cpcmd(cmd, response, rlen, response_code);
110 spin_unlock_irqrestore(&cpcmd_lock, flags);
111 }
112 return len;
113 }
114 EXPORT_SYMBOL(cpcmd);
115
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