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 pr_fmt(fmt) "cpcmd: " fmt
10
11#include <linux/kernel.h>
12#include <linux/export.h>
13#include <linux/slab.h>
14#include <linux/spinlock.h>
15#include <linux/stddef.h>
16#include <linux/string.h>
17#include <linux/mm.h>
18#include <linux/io.h>
19#include <asm/diag.h>
20#include <asm/ebcdic.h>
21#include <asm/cpcmd.h>
22#include <asm/asm.h>
23
24static DEFINE_SPINLOCK(cpcmd_lock);
25static char cpcmd_buf[241];
26
27static 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
37static 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 CC_IPM(cc)
49 : CC_OUT(cc, cc), [ry] "+d" (ry.pair)
50 : [rx] "d" (rx.pair)
51 : CC_CLOBBER);
52 if (CC_TRANSFORM(cc))
53 *rlen += ry.odd;
54 else
55 *rlen = ry.odd;
56 return ry.even;
57}
58
59/*
60 * __cpcmd has some restrictions over cpcmd
61 * - __cpcmd is unlocked and therefore not SMP-safe
62 */
63int __cpcmd(const char *cmd, char *response, int rlen, int *response_code)
64{
65 int cmdlen;
66 int rc;
67 int response_len;
68
69 cmdlen = strlen(cmd);
70 BUG_ON(cmdlen > 240);
71 memcpy(cpcmd_buf, cmd, cmdlen);
72 ASCEBC(cpcmd_buf, cmdlen);
73
74 diag_stat_inc(DIAG_STAT_X008);
75 if (response) {
76 memset(response, 0, rlen);
77 response_len = rlen;
78 rc = diag8_response(cmdlen, response, rlen: &rlen);
79 EBCASC(response, response_len);
80 } else {
81 rc = diag8_noresponse(cmdlen);
82 }
83 if (response_code)
84 *response_code = rc;
85 return rlen;
86}
87EXPORT_SYMBOL(__cpcmd);
88
89int cpcmd(const char *cmd, char *response, int rlen, int *response_code)
90{
91 unsigned long flags;
92 char *lowbuf;
93 int len;
94
95 if (is_vmalloc_or_module_addr(x: response)) {
96 lowbuf = kmalloc(rlen, GFP_KERNEL);
97 if (!lowbuf) {
98 pr_warn("The cpcmd kernel function failed to allocate a response buffer\n");
99 return -ENOMEM;
100 }
101 spin_lock_irqsave(&cpcmd_lock, flags);
102 len = __cpcmd(cmd, lowbuf, rlen, response_code);
103 spin_unlock_irqrestore(lock: &cpcmd_lock, flags);
104 memcpy(response, lowbuf, rlen);
105 kfree(objp: lowbuf);
106 } else {
107 spin_lock_irqsave(&cpcmd_lock, flags);
108 len = __cpcmd(cmd, response, rlen, response_code);
109 spin_unlock_irqrestore(lock: &cpcmd_lock, flags);
110 }
111 return len;
112}
113EXPORT_SYMBOL(cpcmd);
114

source code of linux/arch/s390/kernel/cpcmd.c