LXR linux/arch/s390/kernel/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 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 <asm/diag.h>
  20#include <asm/ebcdic.h>
  21#include <asm/cpcmd.h>
  22#include <asm/io.h>
  23
  24static DEFINE_SPINLOCK(cpcmd_lock);
  25static char cpcmd_buf[241];
  26
  27static 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                "       diag    %1,%0,0x8\n"
  34                : "+d" (reg3) : "d" (reg2) : "cc");
  35        return reg3;
  36}
  37
  38static int diag8_response(int cmdlen, char *response, int *rlen)
  39{
  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;
  44
  45        asm volatile(
  46                "       diag    %2,%0,0x8\n"
  47                "       brc     8,1f\n"
  48                "       agr     %1,%4\n"
  49                "1:\n"
  50                : "+d" (reg4), "+d" (reg5)
  51                : "d" (reg2), "d" (reg3), "d" (*rlen) : "cc");
  52        *rlen = reg5;
  53        return reg4;
  54}
  55
  56/*
  57 * __cpcmd has some restrictions over cpcmd
  58 *  - __cpcmd is unlocked and therefore not SMP-safe
  59 */
  60int  __cpcmd(const char *cmd, char *response, int rlen, int *response_code)
  61{
  62        int cmdlen;
  63        int rc;
  64        int response_len;
  65
  66        cmdlen = strlen(cmd);
  67        BUG_ON(cmdlen > 240);
  68        memcpy(cpcmd_buf, cmd, cmdlen);
  69        ASCEBC(cpcmd_buf, cmdlen);
  70
  71        diag_stat_inc(DIAG_STAT_X008);
  72        if (response) {
  73                memset(response, 0, rlen);
  74                response_len = rlen;
  75                rc = diag8_response(cmdlen, response, &rlen);
  76                EBCASC(response, response_len);
  77        } else {
  78                rc = diag8_noresponse(cmdlen);
  79        }
  80        if (response_code)
  81                *response_code = rc;
  82        return rlen;
  83}
  84EXPORT_SYMBOL(__cpcmd);
  85
  86int cpcmd(const char *cmd, char *response, int rlen, int *response_code)
  87{
  88        unsigned long flags;
  89        char *lowbuf;
  90        int len;
  91
  92        if (is_vmalloc_or_module_addr(response)) {
  93                lowbuf = kmalloc(rlen, GFP_KERNEL);
  94                if (!lowbuf) {
  95                        pr_warn("The cpcmd kernel function failed to allocate a response buffer\n");
  96                        return -ENOMEM;
  97                }
  98                spin_lock_irqsave(&cpcmd_lock, flags);
  99                len = __cpcmd(cmd, lowbuf, rlen, response_code);
 100                spin_unlock_irqrestore(&cpcmd_lock, flags);
 101                memcpy(response, lowbuf, rlen);
 102                kfree(lowbuf);
 103        } else {
 104                spin_lock_irqsave(&cpcmd_lock, flags);
 105                len = __cpcmd(cmd, response, rlen, response_code);
 106                spin_unlock_irqrestore(&cpcmd_lock, flags);
 107        }
 108        return len;
 109}
 110EXPORT_SYMBOL(cpcmd);
 111