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/system.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 #ifndef CONFIG_64BIT
34 " diag %1,%0,0x8\n"
35 #else /* CONFIG_64BIT */
36 " sam31\n"
37 " diag %1,%0,0x8\n"
38 " sam64\n"
39 #endif /* CONFIG_64BIT */
40 : "+d" (reg3) : "d" (reg2) : "cc");
41 return reg3;
42 }
43
diag8_response(int cmdlen,char * response,int * rlen)44 static int diag8_response(int cmdlen, char *response, int *rlen)
45 {
46 register unsigned long reg2 asm ("2") = (addr_t) cpcmd_buf;
47 register unsigned long reg3 asm ("3") = (addr_t) response;
48 register unsigned long reg4 asm ("4") = cmdlen | 0x40000000L;
49 register unsigned long reg5 asm ("5") = *rlen;
50
51 asm volatile(
52 #ifndef CONFIG_64BIT
53 " diag %2,%0,0x8\n"
54 " brc 8,1f\n"
55 " ar %1,%4\n"
56 #else /* CONFIG_64BIT */
57 " sam31\n"
58 " diag %2,%0,0x8\n"
59 " sam64\n"
60 " brc 8,1f\n"
61 " agr %1,%4\n"
62 #endif /* CONFIG_64BIT */
63 "1:\n"
64 : "+d" (reg4), "+d" (reg5)
65 : "d" (reg2), "d" (reg3), "d" (*rlen) : "cc");
66 *rlen = reg5;
67 return reg4;
68 }
69
70 /*
71 * __cpcmd has some restrictions over cpcmd
72 * - the response buffer must reside below 2GB (if any)
73 * - __cpcmd is unlocked and therefore not SMP-safe
74 */
__cpcmd(const char * cmd,char * response,int rlen,int * response_code)75 int __cpcmd(const char *cmd, char *response, int rlen, int *response_code)
76 {
77 int cmdlen;
78 int rc;
79 int response_len;
80
81 cmdlen = strlen(cmd);
82 BUG_ON(cmdlen > 240);
83 memcpy(cpcmd_buf, cmd, cmdlen);
84 ASCEBC(cpcmd_buf, cmdlen);
85
86 if (response) {
87 memset(response, 0, rlen);
88 response_len = rlen;
89 rc = diag8_response(cmdlen, response, &rlen);
90 EBCASC(response, response_len);
91 } else {
92 rc = diag8_noresponse(cmdlen);
93 }
94 if (response_code)
95 *response_code = rc;
96 return rlen;
97 }
98 EXPORT_SYMBOL(__cpcmd);
99
cpcmd(const char * cmd,char * response,int rlen,int * response_code)100 int cpcmd(const char *cmd, char *response, int rlen, int *response_code)
101 {
102 char *lowbuf;
103 int len;
104 unsigned long flags;
105
106 if ((virt_to_phys(response) != (unsigned long) response) ||
107 (((unsigned long)response + rlen) >> 31)) {
108 lowbuf = kmalloc(rlen, GFP_KERNEL | GFP_DMA);
109 if (!lowbuf) {
110 pr_warning("The cpcmd kernel function failed to "
111 "allocate a response buffer\n");
112 return -ENOMEM;
113 }
114 spin_lock_irqsave(&cpcmd_lock, flags);
115 len = __cpcmd(cmd, lowbuf, rlen, response_code);
116 spin_unlock_irqrestore(&cpcmd_lock, flags);
117 memcpy(response, lowbuf, rlen);
118 kfree(lowbuf);
119 } else {
120 spin_lock_irqsave(&cpcmd_lock, flags);
121 len = __cpcmd(cmd, response, rlen, response_code);
122 spin_unlock_irqrestore(&cpcmd_lock, flags);
123 }
124 return len;
125 }
126 EXPORT_SYMBOL(cpcmd);
127