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 <asm/facility-defs.h>
12
13 #include <linux/minmax.h>
14 #include <linux/string.h>
15 #include <linux/types.h>
16 #include <linux/preempt.h>
17 #include <asm/alternative.h>
18 #include <asm/lowcore.h>
19
20 #define MAX_FACILITY_BIT (sizeof(stfle_fac_list) * 8)
21
22 extern u64 stfle_fac_list[16];
23
24 static inline void __set_facility(unsigned long nr, void *facilities)
25 {
26 unsigned char *ptr = (unsigned char *) facilities;
27
28 if (nr >= MAX_FACILITY_BIT)
29 return;
30 ptr[nr >> 3] |= 0x80 >> (nr & 7);
31 }
32
33 static inline void __clear_facility(unsigned long nr, void *facilities)
34 {
35 unsigned char *ptr = (unsigned char *) facilities;
36
37 if (nr >= MAX_FACILITY_BIT)
38 return;
39 ptr[nr >> 3] &= ~(0x80 >> (nr & 7));
40 }
41
42 static __always_inline bool __test_facility(unsigned long nr, void *facilities)
43 {
44 unsigned char *ptr;
45
46 if (nr >= MAX_FACILITY_BIT)
47 return false;
48 ptr = (unsigned char *) facilities + (nr >> 3);
49 return (*ptr & (0x80 >> (nr & 7))) != 0;
50 }
51
52 /*
53 * __test_facility_constant() generates a single instruction branch. If the
54 * tested facility is available (likely) the branch is patched into a nop.
55 *
56 * Do not use this function unless you know what you are doing. All users are
57 * supposed to use test_facility() which will do the right thing.
58 */
59 static __always_inline bool __test_facility_constant(unsigned long nr)
60 {
61 asm goto(
62 ALTERNATIVE("brcl 15,%l[l_no]", "brcl 0,0", ALT_FACILITY(%[nr]))
63 :
64 : [nr] "i" (nr)
65 :
66 : l_no);
67 return true;
68 l_no:
69 return false;
70 }
71
72 /*
73 * The test_facility function uses the bit ordering where the MSB is bit 0.
74 * That makes it easier to query facility bits with the bit number as
75 * documented in the Principles of Operation.
76 */
77 static __always_inline bool test_facility(unsigned long nr)
78 {
79 unsigned long facilities_als[] = { FACILITIES_ALS };
80
81 if (!__is_defined(__DECOMPRESSOR) && __builtin_constant_p(nr)) {
82 if (nr < sizeof(facilities_als) * 8) {
83 if (__test_facility(nr, &facilities_als))
84 return true;
85 }
86 return __test_facility_constant(nr);
87 }
88 return __test_facility(nr, &stfle_fac_list);
89 }
90
91 static inline unsigned long __stfle_asm(u64 *stfle_fac_list, int size)
92 {
93 unsigned long reg0 = size - 1;
94
95 asm volatile(
96 " lgr 0,%[reg0]\n"
97 " .insn s,0xb2b00000,%[list]\n" /* stfle */
98 " lgr %[reg0],0\n"
99 : [reg0] "+&d" (reg0), [list] "+Q" (*stfle_fac_list)
100 :
101 : "memory", "cc", "");
102 return reg0;
103 }
104
105 /**
106 * stfle - Store facility list extended
107 * @stfle_fac_list: array where facility list can be stored
108 * @size: size of passed in array in double words
109 */
110 static inline void __stfle(u64 *stfle_fac_list, int size)
111 {
112 unsigned long nr;
113 u32 stfl_fac_list;
114
115 asm volatile(
116 " stfl 0(0)\n"
117 : "=m" (get_lowcore()->stfl_fac_list));
118 stfl_fac_list = get_lowcore()->stfl_fac_list;
119 memcpy(stfle_fac_list, &stfl_fac_list, 4);
120 nr = 4; /* bytes stored by stfl */
121 if (stfl_fac_list & 0x01000000) {
122 /* More facility bits available with stfle */
123 nr = __stfle_asm(stfle_fac_list, size);
124 nr = min_t(unsigned long, (nr + 1) * 8, size * 8);
125 }
126 memset((char *) stfle_fac_list + nr, 0, size * 8 - nr);
127 }
128
129 static inline void stfle(u64 *stfle_fac_list, int size)
130 {
131 preempt_disable();
132 __stfle(stfle_fac_list, size);
133 preempt_enable();
134 }
135
136 /**
137 * stfle_size - Actual size of the facility list as specified by stfle
138 * (number of double words)
139 */
140 unsigned int stfle_size(void);
141
142 #endif /* __ASM_FACILITY_H */
143
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