LXR linux/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
  20static 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 */
  35static 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 */
  51static 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 */
  77