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 #include <asm/io.h>
  20
  21 static DEFINE_SPINLOCK(cpcmd_lock);
  22 static char cpcmd_buf[241];
  23
  24 /*
  25  * __cpcmd has some restrictions over cpcmd
  26  *  - the response buffer must reside below 2GB (if any)
  27  *  - __cpcmd is unlocked and therefore not SMP-safe
  28  */
  29 int  __cpcmd(const char *cmd, char *response, int rlen, int *response_code)
  30 {
  31         unsigned cmdlen;
  32         int return_code, return_len;
  33
  34         cmdlen = strlen(cmd);
  35         BUG_ON(cmdlen > 240);
  36         memcpy(cpcmd_buf, cmd, cmdlen);
  37         ASCEBC(cpcmd_buf, cmdlen);
  38
  39         if (response != NULL && rlen > 0) {
  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                 memset(response, 0, rlen);
  46                 asm volatile(
  47 #ifndef CONFIG_64BIT
  48                         "       diag    %2,%0,0x8\n"
  49                         "       brc     8,1f\n"
  50                         "       ar      %1,%4\n"
  51 #else /* CONFIG_64BIT */
  52                         "       sam31\n"
  53                         "       diag    %2,%0,0x8\n"
  54                         "       sam64\n"
  55                         "       brc     8,1f\n"
  56                         "       agr     %1,%4\n"
  57 #endif /* CONFIG_64BIT */
  58                         "1:\n"
  59                         : "+d" (reg4), "+d" (reg5)
  60                         : "d" (reg2), "d" (reg3), "d" (rlen) : "cc");
  61                 return_code = (int) reg4;
  62                 return_len = (int) reg5;
  63                 EBCASC(response, rlen);
  64         } else {
  65                 register unsigned long reg2 asm ("2") = (addr_t) cpcmd_buf;
  66                 register unsigned long reg3 asm ("3") = cmdlen;
  67                 return_len = 0;
  68                 asm volatile(
  69 #ifndef CONFIG_64BIT
  70                         "       diag    %1,%0,0x8\n"
  71 #else /* CONFIG_64BIT */
  72                         "       sam31\n"
  73                         "       diag    %1,%0,0x8\n"
  74                         "       sam64\n"
  75 #endif /* CONFIG_64BIT */
  76                         : "+d" (reg3) : "d" (reg2) : "cc");
  77                 return_code = (int) reg3;
  78         }
  79         if (response_code != NULL)
  80                 *response_code = return_code;
  81         return return_len;
  82 }
  83
  84 EXPORT_SYMBOL(__cpcmd);
  85
  86 int cpcmd(const char *cmd, char *response, int rlen, int *response_code)
  87 {
  88         char *lowbuf;
  89         int len;
  90         unsigned long flags;
  91
  92         if ((virt_to_phys(response) != (unsigned long) response) ||
  93                         (((unsigned long)response + rlen) >> 31)) {
  94                 lowbuf = kmalloc(rlen, GFP_KERNEL | GFP_DMA);
  95                 if (!lowbuf) {
  96                         printk(KERN_WARNING
  97                                 "cpcmd: could not allocate response buffer\n");
  98                         return -ENOMEM;
  99                 }
 100                 spin_lock_irqsave(&cpcmd_lock, flags);
 101                 len = __cpcmd(cmd, lowbuf, rlen, response_code);
 102                 spin_unlock_irqrestore(&cpcmd_lock, flags);
 103                 memcpy(response, lowbuf, rlen);
 104                 kfree(lowbuf);
 105         } else {
 106                 spin_lock_irqsave(&cpcmd_lock, flags);
 107                 len = __cpcmd(cmd, response, rlen, response_code);
 108                 spin_unlock_irqrestore(&cpcmd_lock, flags);
 109         }
 110         return len;
 111 }
 112
 113 EXPORT_SYMBOL(cpcmd);