1 /*
2 * arch/s390/kernel/cpcmd.c
3 *
4 * S390 version
5 * Copyright IBM Corp. 1999,2007
6 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
7 * Christian Borntraeger (cborntra@de.ibm.com),
8 */
9
10 #define KMSG_COMPONENT "cpcmd"
11 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
12
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/slab.h>
16 #include <linux/spinlock.h>
17 #include <linux/stddef.h>
18 #include <linux/string.h>
19 #include <asm/ebcdic.h>
20 #include <asm/cpcmd.h>
21 #include <asm/io.h>
22
23 static DEFINE_SPINLOCK(cpcmd_lock);
24 static char cpcmd_buf[241];
25
diag8_noresponse(int cmdlen)26 static int diag8_noresponse(int cmdlen)
27 {
28 register unsigned long reg2 asm ("2") = (addr_t) cpcmd_buf;
29 register unsigned long reg3 asm ("3") = cmdlen;
30
31 asm volatile(
32 #ifndef CONFIG_64BIT
33 " diag %1,%0,0x8\n"
34 #else /* CONFIG_64BIT */
35 " sam31\n"
36 " diag %1,%0,0x8\n"
37 " sam64\n"
38 #endif /* CONFIG_64BIT */
39 : "+d" (reg3) : "d" (reg2) : "cc");
40 return reg3;
41 }
42
diag8_response(int cmdlen,char * response,int * rlen)43 static int diag8_response(int cmdlen, char *response, int *rlen)
44 {
45 register unsigned long reg2 asm ("2") = (addr_t) cpcmd_buf;
46 register unsigned long reg3 asm ("3") = (addr_t) response;
47 register unsigned long reg4 asm ("4") = cmdlen | 0x40000000L;
48 register unsigned long reg5 asm ("5") = *rlen;
49
50 asm volatile(
51 #ifndef CONFIG_64BIT
52 " diag %2,%0,0x8\n"
53 " brc 8,1f\n"
54 " ar %1,%4\n"
55 #else /* CONFIG_64BIT */
56 " sam31\n"
57 " diag %2,%0,0x8\n"
58 " sam64\n"
59 " brc 8,1f\n"
60 " agr %1,%4\n"
61 #endif /* CONFIG_64BIT */
62 "1:\n"
63 : "+d" (reg4), "+d" (reg5)
64 : "d" (reg2), "d" (reg3), "d" (*rlen) : "cc");
65 *rlen = reg5;
66 return reg4;
67 }
68
69 /*
70 * __cpcmd has some restrictions over cpcmd
71 * - the response buffer must reside below 2GB (if any)
72 * - __cpcmd is unlocked and therefore not SMP-safe
73 */
__cpcmd(const char * cmd,char * response,int rlen,int * response_code)74 int __cpcmd(const char *cmd, char *response, int rlen, int *response_code)
75 {
76 int cmdlen;
77 int rc;
78 int response_len;
79
80 cmdlen = strlen(cmd);
81 BUG_ON(cmdlen > 240);
82 memcpy(cpcmd_buf, cmd, cmdlen);
83 ASCEBC(cpcmd_buf, cmdlen);
84
85 if (response) {
86 memset(response, 0, rlen);
87 response_len = rlen;
88 rc = diag8_response(cmdlen, response, &rlen);
89 EBCASC(response, response_len);
90 } else {
91 rc = diag8_noresponse(cmdlen);
92 }
93 if (response_code)
94 *response_code = rc;
95 return rlen;
96 }
97 EXPORT_SYMBOL(__cpcmd);
98
cpcmd(const char * cmd,char * response,int rlen,int * response_code)99 int cpcmd(const char *cmd, char *response, int rlen, int *response_code)
100 {
101 char *lowbuf;
102 int len;
103 unsigned long flags;
104
105 if ((virt_to_phys(response) != (unsigned long) response) ||
106 (((unsigned long)response + rlen) >> 31)) {
107 lowbuf = kmalloc(rlen, GFP_KERNEL | GFP_DMA);
108 if (!lowbuf) {
109 pr_warning("The cpcmd kernel function failed to "
110 "allocate a response buffer\n");
111 return -ENOMEM;
112 }
113 spin_lock_irqsave(&cpcmd_lock, flags);
114 len = __cpcmd(cmd, lowbuf, rlen, response_code);
115 spin_unlock_irqrestore(&cpcmd_lock, flags);
116 memcpy(response, lowbuf, rlen);
117 kfree(lowbuf);
118 } else {
119 spin_lock_irqsave(&cpcmd_lock, flags);
120 len = __cpcmd(cmd, response, rlen, response_code);
121 spin_unlock_irqrestore(&cpcmd_lock, flags);
122 }
123 return len;
124 }
125 EXPORT_SYMBOL(cpcmd);
126