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  * the caller of __cpcmd has to ensure that the response buffer is below 2 GB
  25  */
  26 int  __cpcmd(const char *cmd, char *response, int rlen, int *response_code)
  27 {
  28         const int mask = 0x40000000L;
  29         unsigned long flags;
  30         int return_code;
  31         int return_len;
  32         int cmdlen;
  33
  34         spin_lock_irqsave(&cpcmd_lock, flags);
  35         cmdlen = strlen(cmd);
  36         BUG_ON(cmdlen > 240);
  37         memcpy(cpcmd_buf, cmd, cmdlen);
  38         ASCEBC(cpcmd_buf, cmdlen);
  39
  40         if (response != NULL && rlen > 0) {
  41                 memset(response, 0, rlen);
  42 #ifndef CONFIG_64BIT
  43                 asm volatile (  "lra    2,0(%2)\n"
  44                                 "lr     4,%3\n"
  45                                 "o      4,%6\n"
  46                                 "lra    3,0(%4)\n"
  47                                 "lr     5,%5\n"
  48                                 "diag   2,4,0x8\n"
  49                                 "brc    8, 1f\n"
  50                                 "ar     5, %5\n"
  51                                 "1: \n"
  52                                 "lr     %0,4\n"
  53                                 "lr     %1,5\n"
  54                                 : "=d" (return_code), "=d" (return_len)
  55                                 : "a" (cpcmd_buf), "d" (cmdlen),
  56                                 "a" (response), "d" (rlen), "m" (mask)
  57                                 : "cc", "2", "3", "4", "5" );
  58 #else /* CONFIG_64BIT */
  59                 asm volatile (  "lrag   2,0(%2)\n"
  60                                 "lgr    4,%3\n"
  61                                 "o      4,%6\n"
  62                                 "lrag   3,0(%4)\n"
  63                                 "lgr    5,%5\n"
  64                                 "sam31\n"
  65                                 "diag   2,4,0x8\n"
  66                                 "sam64\n"
  67                                 "brc    8, 1f\n"
  68                                 "agr    5, %5\n"
  69                                 "1: \n"
  70                                 "lgr    %0,4\n"
  71                                 "lgr    %1,5\n"
  72                                 : "=d" (return_code), "=d" (return_len)
  73                                 : "a" (cpcmd_buf), "d" (cmdlen),
  74                                 "a" (response), "d" (rlen), "m" (mask)
  75                                 : "cc", "2", "3", "4", "5" );
  76 #endif /* CONFIG_64BIT */
  77                 EBCASC(response, rlen);
  78         } else {
  79                 return_len = 0;
  80 #ifndef CONFIG_64BIT
  81                 asm volatile (  "lra    2,0(%1)\n"
  82                                 "lr     3,%2\n"
  83                                 "diag   2,3,0x8\n"
  84                                 "lr     %0,3\n"
  85                                 : "=d" (return_code)
  86                                 : "a" (cpcmd_buf), "d" (cmdlen)
  87                                 : "2", "3"  );
  88 #else /* CONFIG_64BIT */
  89                 asm volatile (  "lrag   2,0(%1)\n"
  90                                 "lgr    3,%2\n"
  91                                 "sam31\n"
  92                                 "diag   2,3,0x8\n"
  93                                 "sam64\n"
  94                                 "lgr    %0,3\n"
  95                                 : "=d" (return_code)
  96                                 : "a" (cpcmd_buf), "d" (cmdlen)
  97                                 : "2", "3" );
  98 #endif /* CONFIG_64BIT */
  99         }
 100         spin_unlock_irqrestore(&cpcmd_lock, flags);
 101         if (response_code != NULL)
 102                 *response_code = return_code;
 103         return return_len;
 104 }
 105
 106 EXPORT_SYMBOL(__cpcmd);
 107
 108 #ifdef CONFIG_64BIT
 109 int cpcmd(const char *cmd, char *response, int rlen, int *response_code)
 110 {
 111         char *lowbuf;
 112         int len;
 113
 114         if ((rlen == 0) || (response == NULL)
 115             || !((unsigned long)response >> 31))
 116                 len = __cpcmd(cmd, response, rlen, response_code);
 117         else {
 118                 lowbuf = kmalloc(rlen, GFP_KERNEL | GFP_DMA);
 119                 if (!lowbuf) {
 120                         printk(KERN_WARNING
 121                                 "cpcmd: could not allocate response buffer\n");
 122                         return -ENOMEM;
 123                 }
 124                 len = __cpcmd(cmd, lowbuf, rlen, response_code);
 125                 memcpy(response, lowbuf, rlen);
 126                 kfree(lowbuf);
 127         }
 128         return len;
 129 }
 130
 131 EXPORT_SYMBOL(cpcmd);
 132 #endif          /* CONFIG_64BIT */