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 <linux/io.h>
20#include <asm/diag.h>
21#include <asm/ebcdic.h>
22#include <asm/cpcmd.h>
23
24static DEFINE_SPINLOCK(cpcmd_lock);
25static char cpcmd_buf[241];
26
27static int diag8_noresponse(int cmdlen)
28{
29	asm volatile(
30		"	diag	%[rx],%[ry],0x8\n"
31		: [ry] "+&d" (cmdlen)
32		: [rx] "d" (__pa(cpcmd_buf))
33		: "cc");
34	return cmdlen;
35}
36
37static int diag8_response(int cmdlen, char *response, int *rlen)
38{
39	union register_pair rx, ry;
40	int cc;
41
42	rx.even = __pa(cpcmd_buf);
43	rx.odd	= __pa(response);
44	ry.even = cmdlen | 0x40000000L;
45	ry.odd	= *rlen;
46	asm volatile(
47		"	diag	%[rx],%[ry],0x8\n"
48		"	ipm	%[cc]\n"
49		"	srl	%[cc],28\n"
50		: [cc] "=&d" (cc), [ry] "+&d" (ry.pair)
51		: [rx] "d" (rx.pair)
52		: "cc");
53	if (cc)
54		*rlen += ry.odd;
55	else
56		*rlen = ry.odd;
57	return ry.even;
58}
59
60/*
61 * __cpcmd has some restrictions over cpcmd
62 *  - __cpcmd is unlocked and therefore not SMP-safe
63 */
64int  __cpcmd(const char *cmd, char *response, int rlen, int *response_code)
65{
66	int cmdlen;
67	int rc;
68	int response_len;
69
70	cmdlen = strlen(cmd);
71	BUG_ON(cmdlen > 240);
72	memcpy(cpcmd_buf, cmd, cmdlen);
73	ASCEBC(cpcmd_buf, cmdlen);
74
75	diag_stat_inc(DIAG_STAT_X008);
76	if (response) {
77		memset(response, 0, rlen);
78		response_len = rlen;
79		rc = diag8_response(cmdlen, response, &rlen);
80		EBCASC(response, response_len);
81        } else {
82		rc = diag8_noresponse(cmdlen);
83        }
84	if (response_code)
85		*response_code = rc;
86	return rlen;
87}
88EXPORT_SYMBOL(__cpcmd);
89
90int cpcmd(const char *cmd, char *response, int rlen, int *response_code)
91{
92	unsigned long flags;
93	char *lowbuf;
94	int len;
95
96	if (is_vmalloc_or_module_addr(response)) {
97		lowbuf = kmalloc(rlen, GFP_KERNEL);
98		if (!lowbuf) {
99			pr_warn("The cpcmd kernel function failed to allocate a response buffer\n");
100			return -ENOMEM;
101		}
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);
111	}
112	return len;
113}
114EXPORT_SYMBOL(cpcmd);
115