arch/s390/include/asm/facility.h

   1 /*
   2  * Copyright IBM Corp. 1999, 2009
   3  *
   4  * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
   5  */
   6
   7 #ifndef __ASM_FACILITY_H
   8 #define __ASM_FACILITY_H
   9
  10 #include <linux/string.h>
  11 #include <linux/preempt.h>
  12 #include <asm/lowcore.h>
  13
  14 #define MAX_FACILITY_BIT (256*8)        /* stfle_fac_list has 256 bytes */
  15
  16 static inline int __test_facility(unsigned long nr, void *facilities)
  17 {
  18         unsigned char *ptr;
  19
  20         if (nr >= MAX_FACILITY_BIT)
  21                 return 0;
  22         ptr = (unsigned char *) facilities + (nr >> 3);
  23         return (*ptr & (0x80 >> (nr & 7))) != 0;
  24 }
  25
  26 /*
  27  * The test_facility function uses the bit odering where the MSB is bit 0.
  28  * That makes it easier to query facility bits with the bit number as
  29  * documented in the Principles of Operation.
  30  */
  31 static inline int test_facility(unsigned long nr)
  32 {
  33         return __test_facility(nr, &S390_lowcore.stfle_fac_list);
  34 }
  35
  36 /**
  37  * stfle - Store facility list extended
  38  * @stfle_fac_list: array where facility list can be stored
  39  * @size: size of passed in array in double words
  40  */
  41 static inline void stfle(u64 *stfle_fac_list, int size)
  42 {
  43         unsigned long nr;
  44
  45         preempt_disable();
  46         asm volatile(
  47                 "       .insn s,0xb2b10000,0(0)\n" /* stfl */
  48                 "0:\n"
  49                 EX_TABLE(0b, 0b)
  50                 : "+m" (S390_lowcore.stfl_fac_list));
  51         nr = 4; /* bytes stored by stfl */
  52         memcpy(stfle_fac_list, &S390_lowcore.stfl_fac_list, 4);
  53         if (S390_lowcore.stfl_fac_list & 0x01000000) {
  54                 /* More facility bits available with stfle */
  55                 register unsigned long reg0 asm("0") = size - 1;
  56
  57                 asm volatile(".insn s,0xb2b00000,0(%1)" /* stfle */
  58                              : "+d" (reg0)
  59                              : "a" (stfle_fac_list)
  60                              : "memory", "cc");
  61                 nr = (reg0 + 1) * 8; /* # bytes stored by stfle */
  62         }
  63         memset((char *) stfle_fac_list + nr, 0, size * 8 - nr);
  64         preempt_enable();
  65 }
  66
  67 #endif /* __ASM_FACILITY_H */