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 <generated/facilities.h>
  11
  12 #ifndef __ASSEMBLY__
  13
  14 #include <linux/string.h>
  15 #include <linux/preempt.h>
  16 #include <asm/lowcore.h>
  17
  18 #define MAX_FACILITY_BIT (256*8)        /* stfle_fac_list has 256 bytes */
  19
  20 static inline int __test_facility(unsigned long nr, void *facilities)
  21 {
  22         unsigned char *ptr;
  23
  24         if (nr >= MAX_FACILITY_BIT)
  25                 return 0;
  26         ptr = (unsigned char *) facilities + (nr >> 3);
  27         return (*ptr & (0x80 >> (nr & 7))) != 0;
  28 }
  29
  30 /*
  31  * The test_facility function uses the bit odering where the MSB is bit 0.
  32  * That makes it easier to query facility bits with the bit number as
  33  * documented in the Principles of Operation.
  34  */
  35 static inline int test_facility(unsigned long nr)
  36 {
  37         unsigned long facilities_als[] = { FACILITIES_ALS };
  38
  39         if (__builtin_constant_p(nr) && nr < sizeof(facilities_als) * 8) {
  40                 if (__test_facility(nr, &facilities_als))
  41                         return 1;
  42         }
  43         return __test_facility(nr, &S390_lowcore.stfle_fac_list);
  44 }
  45
  46 /**
  47  * stfle - Store facility list extended
  48  * @stfle_fac_list: array where facility list can be stored
  49  * @size: size of passed in array in double words
  50  */
  51 static inline void stfle(u64 *stfle_fac_list, int size)
  52 {
  53         unsigned long nr;
  54
  55         preempt_disable();
  56         asm volatile(
  57                 "       stfl    0(0)\n"
  58                 : "=m" (S390_lowcore.stfl_fac_list));
  59         nr = 4; /* bytes stored by stfl */
  60         memcpy(stfle_fac_list, &S390_lowcore.stfl_fac_list, 4);
  61         if (S390_lowcore.stfl_fac_list & 0x01000000) {
  62                 /* More facility bits available with stfle */
  63                 register unsigned long reg0 asm("0") = size - 1;
  64
  65                 asm volatile(".insn s,0xb2b00000,0(%1)" /* stfle */
  66                              : "+d" (reg0)
  67                              : "a" (stfle_fac_list)
  68                              : "memory", "cc");
  69                 nr = (reg0 + 1) * 8; /* # bytes stored by stfle */
  70         }
  71         memset((char *) stfle_fac_list + nr, 0, size * 8 - nr);
  72         preempt_enable();
  73 }
  74
  75 #endif /* __ASSEMBLY__ */
  76 #endif /* __ASM_FACILITY_H */