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 <asm/diag.h>
20 #include <asm/ebcdic.h>
21 #include <asm/cpcmd.h>
22 #include <asm/io.h>
23
24 static DEFINE_SPINLOCK(cpcmd_lock);
25 static char cpcmd_buf[241];
26
diag8_noresponse(int cmdlen)27 static int diag8_noresponse(int cmdlen)
28 {
29 register unsigned long reg2 asm ("2") = (addr_t) cpcmd_buf;
30 register unsigned long reg3 asm ("3") = cmdlen;
31
32 asm volatile(
33 " diag %1,%0,0x8\n"
34 : "+d" (reg3) : "d" (reg2) : "cc");
35 return reg3;
36 }
37
diag8_response(int cmdlen,char * response,int * rlen)38 static int diag8_response(int cmdlen, char *response, int *rlen)
39 {
40 register unsigned long reg2 asm ("2") = (addr_t) cpcmd_buf;
41 register unsigned long reg3 asm ("3") = (addr_t) response;
42 register unsigned long reg4 asm ("4") = cmdlen | 0x40000000L;
43 register unsigned long reg5 asm ("5") = *rlen;
44
45 asm volatile(
46 " diag %2,%0,0x8\n"
47 " brc 8,1f\n"
48 " agr %1,%4\n"
49 "1:\n"
50 : "+d" (reg4), "+d" (reg5)
51 : "d" (reg2), "d" (reg3), "d" (*rlen) : "cc");
52 *rlen = reg5;
53 return reg4;
54 }
55
56 /*
57 * __cpcmd has some restrictions over cpcmd
58 * - __cpcmd is unlocked and therefore not SMP-safe
59 */
__cpcmd(const char * cmd,char * response,int rlen,int * response_code)60 int __cpcmd(const char *cmd, char *response, int rlen, int *response_code)
61 {
62 int cmdlen;
63 int rc;
64 int response_len;
65
66 cmdlen = strlen(cmd);
67 BUG_ON(cmdlen > 240);
68 memcpy(cpcmd_buf, cmd, cmdlen);
69 ASCEBC(cpcmd_buf, cmdlen);
70
71 diag_stat_inc(DIAG_STAT_X008);
72 if (response) {
73 memset(response, 0, rlen);
74 response_len = rlen;
75 rc = diag8_response(cmdlen, response, &rlen);
76 EBCASC(response, response_len);
77 } else {
78 rc = diag8_noresponse(cmdlen);
79 }
80 if (response_code)
81 *response_code = rc;
82 return rlen;
83 }
84 EXPORT_SYMBOL(__cpcmd);
85
cpcmd(const char * cmd,char * response,int rlen,int * response_code)86 int cpcmd(const char *cmd, char *response, int rlen, int *response_code)
87 {
88 unsigned long flags;
89 char *lowbuf;
90 int len;
91
92 if (is_vmalloc_or_module_addr(response)) {
93 lowbuf = kmalloc(rlen, GFP_KERNEL);
94 if (!lowbuf) {
95 pr_warn("The cpcmd kernel function failed to allocate a response buffer\n");
96 return -ENOMEM;
97 }
98 spin_lock_irqsave(&cpcmd_lock, flags);
99 len = __cpcmd(cmd, lowbuf, rlen, response_code);
100 spin_unlock_irqrestore(&cpcmd_lock, flags);
101 memcpy(response, lowbuf, rlen);
102 kfree(lowbuf);
103 } else {
104 spin_lock_irqsave(&cpcmd_lock, flags);
105 len = __cpcmd(cmd, response, rlen, response_code);
106 spin_unlock_irqrestore(&cpcmd_lock, flags);
107 }
108 return len;
109 }
110 EXPORT_SYMBOL(cpcmd);
111
