cpcmd.c

  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 pr_fmt(fmt) "cpcmd: " fmt
 10
 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 <linux/mm.h>
 18#include <linux/io.h>
 19#include <asm/diag.h>
 20#include <asm/ebcdic.h>
 21#include <asm/cpcmd.h>
 22#include <asm/asm.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		CC_IPM(cc)
 49		: CC_OUT(cc, cc), [ry] "+d" (ry.pair)
 50		: [rx] "d" (rx.pair)
 51		: CC_CLOBBER);
 52	if (CC_TRANSFORM(cc))
 53		*rlen += ry.odd;
 54	else
 55		*rlen = ry.odd;
 56	return ry.even;
 57}
 58
 59/*
 60 * __cpcmd has some restrictions over cpcmd
 61 *  - __cpcmd is unlocked and therefore not SMP-safe
 62 */
 63int  __cpcmd(const char *cmd, char *response, int rlen, int *response_code)
 64{
 65	int cmdlen;
 66	int rc;
 67	int response_len;
 68
 69	cmdlen = strlen(cmd);
 70	BUG_ON(cmdlen > 240);
 71	memcpy(cpcmd_buf, cmd, cmdlen);
 72	ASCEBC(cpcmd_buf, cmdlen);
 73
 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);
 82        }
 83	if (response_code)
 84		*response_code = rc;
 85	return rlen;
 86}
 87EXPORT_SYMBOL(__cpcmd);
 88
 89int cpcmd(const char *cmd, char *response, int rlen, int *response_code)
 90{
 91	unsigned long flags;
 92	char *lowbuf;
 93	int len;
 94
 95	if (is_vmalloc_or_module_addr(response)) {
 96		lowbuf = kmalloc(rlen, GFP_KERNEL);
 97		if (!lowbuf) {
 98			pr_warn("The cpcmd kernel function failed to allocate a response buffer\n");
 99			return -ENOMEM;
100		}
101		spin_lock_irqsave(&cpcmd_lock, flags);
102		len = __cpcmd(cmd, lowbuf, rlen, response_code);
103		spin_unlock_irqrestore(&cpcmd_lock, flags);
104		memcpy(response, lowbuf, rlen);
105		kfree(lowbuf);
106	} else {
107		spin_lock_irqsave(&cpcmd_lock, flags);
108		len = __cpcmd(cmd, response, rlen, response_code);
109		spin_unlock_irqrestore(&cpcmd_lock, flags);
110	}
111	return len;
112}
113EXPORT_SYMBOL(cpcmd);