1 /*
2 * S390 version
3 * Copyright IBM Corp. 1999, 2007
4 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
5 * Christian Borntraeger (cborntra@de.ibm.com),
6 */
7
8 #define KMSG_COMPONENT "cpcmd"
9 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
10
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/slab.h>
14 #include <linux/spinlock.h>
15 #include <linux/stddef.h>
16 #include <linux/string.h>
17 #include <asm/ebcdic.h>
18 #include <asm/cpcmd.h>
19 #include <asm/io.h>
20
21 static DEFINE_SPINLOCK(cpcmd_lock);
22 static char cpcmd_buf[241];
23
diag8_noresponse(int cmdlen)24 static int diag8_noresponse(int cmdlen)
25 {
26 register unsigned long reg2 asm ("2") = (addr_t) cpcmd_buf;
27 register unsigned long reg3 asm ("3") = cmdlen;
28
29 asm volatile(
30 #ifndef CONFIG_64BIT
31 " diag %1,%0,0x8\n"
32 #else /* CONFIG_64BIT */
33 " sam31\n"
34 " diag %1,%0,0x8\n"
35 " sam64\n"
36 #endif /* CONFIG_64BIT */
37 : "+d" (reg3) : "d" (reg2) : "cc");
38 return reg3;
39 }
40
diag8_response(int cmdlen,char * response,int * rlen)41 static int diag8_response(int cmdlen, char *response, int *rlen)
42 {
43 register unsigned long reg2 asm ("2") = (addr_t) cpcmd_buf;
44 register unsigned long reg3 asm ("3") = (addr_t) response;
45 register unsigned long reg4 asm ("4") = cmdlen | 0x40000000L;
46 register unsigned long reg5 asm ("5") = *rlen;
47
48 asm volatile(
49 #ifndef CONFIG_64BIT
50 " diag %2,%0,0x8\n"
51 " brc 8,1f\n"
52 " ar %1,%4\n"
53 #else /* CONFIG_64BIT */
54 " sam31\n"
55 " diag %2,%0,0x8\n"
56 " sam64\n"
57 " brc 8,1f\n"
58 " agr %1,%4\n"
59 #endif /* CONFIG_64BIT */
60 "1:\n"
61 : "+d" (reg4), "+d" (reg5)
62 : "d" (reg2), "d" (reg3), "d" (*rlen) : "cc");
63 *rlen = reg5;
64 return reg4;
65 }
66
67 /*
68 * __cpcmd has some restrictions over cpcmd
69 * - the response buffer must reside below 2GB (if any)
70 * - __cpcmd is unlocked and therefore not SMP-safe
71 */
__cpcmd(const char * cmd,char * response,int rlen,int * response_code)72 int __cpcmd(const char *cmd, char *response, int rlen, int *response_code)
73 {
74 int cmdlen;
75 int rc;
76 int response_len;
77
78 cmdlen = strlen(cmd);
79 BUG_ON(cmdlen > 240);
80 memcpy(cpcmd_buf, cmd, cmdlen);
81 ASCEBC(cpcmd_buf, cmdlen);
82
83 if (response) {
84 memset(response, 0, rlen);
85 response_len = rlen;
86 rc = diag8_response(cmdlen, response, &rlen);
87 EBCASC(response, response_len);
88 } else {
89 rc = diag8_noresponse(cmdlen);
90 }
91 if (response_code)
92 *response_code = rc;
93 return rlen;
94 }
95 EXPORT_SYMBOL(__cpcmd);
96
cpcmd(const char * cmd,char * response,int rlen,int * response_code)97 int cpcmd(const char *cmd, char *response, int rlen, int *response_code)
98 {
99 char *lowbuf;
100 int len;
101 unsigned long flags;
102
103 if ((virt_to_phys(response) != (unsigned long) response) ||
104 (((unsigned long)response + rlen) >> 31)) {
105 lowbuf = kmalloc(rlen, GFP_KERNEL | GFP_DMA);
106 if (!lowbuf) {
107 pr_warning("The cpcmd kernel function failed to "
108 "allocate a response buffer\n");
109 return -ENOMEM;
110 }
111 spin_lock_irqsave(&cpcmd_lock, flags);
112 len = __cpcmd(cmd, lowbuf, rlen, response_code);
113 spin_unlock_irqrestore(&cpcmd_lock, flags);
114 memcpy(response, lowbuf, rlen);
115 kfree(lowbuf);
116 } else {
117 spin_lock_irqsave(&cpcmd_lock, flags);
118 len = __cpcmd(cmd, response, rlen, response_code);
119 spin_unlock_irqrestore(&cpcmd_lock, flags);
120 }
121 return len;
122 }
123 EXPORT_SYMBOL(cpcmd);
124