xref: /openbmc/linux/arch/s390/include/asm/facility.h (revision 0edbfea5)
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 */
77