Linux 4.13.16
[linux/fpc-iii.git] / arch / s390 / kernel / cpcmd.c
blob9f0e4a2785f7fb74d7863da83ba89a0a3458b539
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 */
8 #define KMSG_COMPONENT "cpcmd"
9 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
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 <asm/diag.h>
18 #include <asm/ebcdic.h>
19 #include <asm/cpcmd.h>
20 #include <asm/io.h>
22 static DEFINE_SPINLOCK(cpcmd_lock);
23 static char cpcmd_buf[241];
25 static int diag8_noresponse(int cmdlen)
27 register unsigned long reg2 asm ("2") = (addr_t) cpcmd_buf;
28 register unsigned long reg3 asm ("3") = cmdlen;
30 asm volatile(
31 " sam31\n"
32 " diag %1,%0,0x8\n"
33 " sam64\n"
34 : "+d" (reg3) : "d" (reg2) : "cc");
35 return reg3;
38 static int diag8_response(int cmdlen, char *response, int *rlen)
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;
45 asm volatile(
46 " sam31\n"
47 " diag %2,%0,0x8\n"
48 " sam64\n"
49 " brc 8,1f\n"
50 " agr %1,%4\n"
51 "1:\n"
52 : "+d" (reg4), "+d" (reg5)
53 : "d" (reg2), "d" (reg3), "d" (*rlen) : "cc");
54 *rlen = reg5;
55 return reg4;
59 * __cpcmd has some restrictions over cpcmd
60 * - the response buffer must reside below 2GB (if any)
61 * - __cpcmd is unlocked and therefore not SMP-safe
63 int __cpcmd(const char *cmd, char *response, int rlen, int *response_code)
65 int cmdlen;
66 int rc;
67 int response_len;
69 cmdlen = strlen(cmd);
70 BUG_ON(cmdlen > 240);
71 memcpy(cpcmd_buf, cmd, cmdlen);
72 ASCEBC(cpcmd_buf, cmdlen);
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);
79 EBCASC(response, response_len);
80 } else {
81 rc = diag8_noresponse(cmdlen);
83 if (response_code)
84 *response_code = rc;
85 return rlen;
87 EXPORT_SYMBOL(__cpcmd);
89 int cpcmd(const char *cmd, char *response, int rlen, int *response_code)
91 char *lowbuf;
92 int len;
93 unsigned long flags;
95 if ((virt_to_phys(response) != (unsigned long) response) ||
96 (((unsigned long)response + rlen) >> 31)) {
97 lowbuf = kmalloc(rlen, GFP_KERNEL | GFP_DMA);
98 if (!lowbuf) {
99 pr_warn("The cpcmd kernel function failed to allocate a response buffer\n");
100 return -ENOMEM;
102 spin_lock_irqsave(&cpcmd_lock, flags);
103 len = __cpcmd(cmd, lowbuf, rlen, response_code);
104 spin_unlock_irqrestore(&cpcmd_lock, flags);
105 memcpy(response, lowbuf, rlen);
106 kfree(lowbuf);
107 } else {
108 spin_lock_irqsave(&cpcmd_lock, flags);
109 len = __cpcmd(cmd, response, rlen, response_code);
110 spin_unlock_irqrestore(&cpcmd_lock, flags);
112 return len;
114 EXPORT_SYMBOL(cpcmd);