arch/s390/kernel/cpcmd.c

   1 /*
   2  *  arch/s390/kernel/cpcmd.c
   3  *
   4  *  S390 version
   5  *    Copyright (C) 1999,2005 IBM Deutschland Entwicklung GmbH, IBM Corporation
   6  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
   7  *               Christian Borntraeger (cborntra@de.ibm.com),
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/slab.h>
  13 #include <linux/spinlock.h>
  14 #include <linux/stddef.h>
  15 #include <linux/string.h>
  16 #include <asm/ebcdic.h>
  17 #include <asm/cpcmd.h>
  18 #include <asm/system.h>
  19
  20 static DEFINE_SPINLOCK(cpcmd_lock);
  21 static char cpcmd_buf[241];
  22
  23 /*
  24  * __cpcmd has some restrictions over cpcmd
  25  *  - the response buffer must reside below 2GB (if any)
  26  *  - __cpcmd is unlocked and therefore not SMP-safe
  27  */
  28 int  __cpcmd(const char *cmd, char *response, int rlen, int *response_code)
  29 {
  30         unsigned cmdlen;
  31         int return_code, return_len;
  32
  33         cmdlen = strlen(cmd);
  34         BUG_ON(cmdlen > 240);
  35         memcpy(cpcmd_buf, cmd, cmdlen);
  36         ASCEBC(cpcmd_buf, cmdlen);
  37
  38         if (response != NULL && rlen > 0) {
  39                 register unsigned long reg2 asm ("2") = (addr_t) cpcmd_buf;
  40                 register unsigned long reg3 asm ("3") = (addr_t) response;
  41                 register unsigned long reg4 asm ("4") = cmdlen | 0x40000000L;
  42                 register unsigned long reg5 asm ("5") = rlen;
  43
  44                 memset(response, 0, rlen);
  45                 asm volatile(
  46 #ifndef CONFIG_64BIT
  47                         "       diag    %2,%0,0x8\n"
  48                         "       brc     8,1f\n"
  49                         "       ar      %1,%4\n"
  50 #else /* CONFIG_64BIT */
  51                         "       sam31\n"
  52                         "       diag    %2,%0,0x8\n"
  53                         "       sam64\n"
  54                         "       brc     8,1f\n"
  55                         "       agr     %1,%4\n"
  56 #endif /* CONFIG_64BIT */
  57                         "1:\n"
  58                         : "+d" (reg4), "+d" (reg5)
  59                         : "d" (reg2), "d" (reg3), "d" (rlen) : "cc");
  60                 return_code = (int) reg4;
  61                 return_len = (int) reg5;
  62                 EBCASC(response, rlen);
  63         } else {
  64                 register unsigned long reg2 asm ("2") = (addr_t) cpcmd_buf;
  65                 register unsigned long reg3 asm ("3") = cmdlen;
  66                 return_len = 0;
  67                 asm volatile(
  68 #ifndef CONFIG_64BIT
  69                         "       diag    %1,%0,0x8\n"
  70 #else /* CONFIG_64BIT */
  71                         "       sam31\n"
  72                         "       diag    %1,%0,0x8\n"
  73                         "       sam64\n"
  74 #endif /* CONFIG_64BIT */
  75                         : "+d" (reg3) : "d" (reg2) : "cc");
  76                 return_code = (int) reg3;
  77         }
  78         if (response_code != NULL)
  79                 *response_code = return_code;
  80         return return_len;
  81 }
  82
  83 EXPORT_SYMBOL(__cpcmd);
  84
  85 int cpcmd(const char *cmd, char *response, int rlen, int *response_code)
  86 {
  87         char *lowbuf;
  88         int len;
  89         unsigned long flags;
  90
  91         if ((rlen == 0) || (response == NULL)
  92             || !((unsigned long)response >> 31)) {
  93                 spin_lock_irqsave(&cpcmd_lock, flags);
  94                 len = __cpcmd(cmd, response, rlen, response_code);
  95                 spin_unlock_irqrestore(&cpcmd_lock, flags);
  96         }
  97         else {
  98                 lowbuf = kmalloc(rlen, GFP_KERNEL | GFP_DMA);
  99                 if (!lowbuf) {
 100                         printk(KERN_WARNING
 101                                 "cpcmd: could not allocate response buffer\n");
 102                         return -ENOMEM;
 103                 }
 104                 spin_lock_irqsave(&cpcmd_lock, flags);
 105                 len = __cpcmd(cmd, lowbuf, rlen, response_code);
 106                 spin_unlock_irqrestore(&cpcmd_lock, flags);
 107                 memcpy(response, lowbuf, rlen);
 108                 kfree(lowbuf);
 109         }
 110         return len;
 111 }
 112
 113 EXPORT_SYMBOL(cpcmd);