arch/s390/include/asm/facility.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Copyright IBM Corp. 1999, 2009
   4  *
   5  * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
   6  */
   7
   8 #ifndef __ASM_FACILITY_H
   9 #define __ASM_FACILITY_H
  10
  11 #include <generated/facilities.h>
  12 #include <linux/string.h>
  13 #include <linux/preempt.h>
  14 #include <asm/lowcore.h>
  15
  16 #define MAX_FACILITY_BIT (sizeof(((struct lowcore *)0)->stfle_fac_list) * 8)
  17
  18 static inline int __test_facility(unsigned long nr, void *facilities)
  19 {
  20         unsigned char *ptr;
  21
  22         if (nr >= MAX_FACILITY_BIT)
  23                 return 0;
  24         ptr = (unsigned char *) facilities + (nr >> 3);
  25         return (*ptr & (0x80 >> (nr & 7))) != 0;
  26 }
  27
  28 /*
  29  * The test_facility function uses the bit odering where the MSB is bit 0.
  30  * That makes it easier to query facility bits with the bit number as
  31  * documented in the Principles of Operation.
  32  */
  33 static inline int test_facility(unsigned long nr)
  34 {
  35         unsigned long facilities_als[] = { FACILITIES_ALS };
  36
  37         if (__builtin_constant_p(nr) && nr < sizeof(facilities_als) * 8) {
  38                 if (__test_facility(nr, &facilities_als))
  39                         return 1;
  40         }
  41         return __test_facility(nr, &S390_lowcore.stfle_fac_list);
  42 }
  43
  44 /**
  45  * stfle - Store facility list extended
  46  * @stfle_fac_list: array where facility list can be stored
  47  * @size: size of passed in array in double words
  48  */
  49 static inline void stfle(u64 *stfle_fac_list, int size)
  50 {
  51         unsigned long nr;
  52
  53         preempt_disable();
  54         asm volatile(
  55                 "       stfl    0(0)\n"
  56                 : "=m" (S390_lowcore.stfl_fac_list));
  57         nr = 4; /* bytes stored by stfl */
  58         memcpy(stfle_fac_list, &S390_lowcore.stfl_fac_list, 4);
  59         if (S390_lowcore.stfl_fac_list & 0x01000000) {
  60                 /* More facility bits available with stfle */
  61                 register unsigned long reg0 asm("0") = size - 1;
  62
  63                 asm volatile(".insn s,0xb2b00000,0(%1)" /* stfle */
  64                              : "+d" (reg0)
  65                              : "a" (stfle_fac_list)
  66                              : "memory", "cc");
  67                 nr = (reg0 + 1) * 8; /* # bytes stored by stfle */
  68         }
  69         memset((char *) stfle_fac_list + nr, 0, size * 8 - nr);
  70         preempt_enable();
  71 }
  72
  73 #endif /* __ASM_FACILITY_H */