xref: /linux/arch/s390/include/asm/facility.h (revision 93d90ad708b8da6efc0e487b66111aa9db7f70c7)
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 <linux/string.h>
11 #include <linux/preempt.h>
12 #include <asm/lowcore.h>
13 
14 #define MAX_FACILITY_BIT (256*8)	/* stfle_fac_list has 256 bytes */
15 
16 static inline int __test_facility(unsigned long nr, void *facilities)
17 {
18 	unsigned char *ptr;
19 
20 	if (nr >= MAX_FACILITY_BIT)
21 		return 0;
22 	ptr = (unsigned char *) facilities + (nr >> 3);
23 	return (*ptr & (0x80 >> (nr & 7))) != 0;
24 }
25 
26 /*
27  * The test_facility function uses the bit odering where the MSB is bit 0.
28  * That makes it easier to query facility bits with the bit number as
29  * documented in the Principles of Operation.
30  */
31 static inline int test_facility(unsigned long nr)
32 {
33 	return __test_facility(nr, &S390_lowcore.stfle_fac_list);
34 }
35 
36 /**
37  * stfle - Store facility list extended
38  * @stfle_fac_list: array where facility list can be stored
39  * @size: size of passed in array in double words
40  */
41 static inline void stfle(u64 *stfle_fac_list, int size)
42 {
43 	unsigned long nr;
44 
45 	preempt_disable();
46 	asm volatile(
47 		"	.insn s,0xb2b10000,0(0)\n" /* stfl */
48 		"0:\n"
49 		EX_TABLE(0b, 0b)
50 		: "+m" (S390_lowcore.stfl_fac_list));
51 	nr = 4; /* bytes stored by stfl */
52 	memcpy(stfle_fac_list, &S390_lowcore.stfl_fac_list, 4);
53 	if (S390_lowcore.stfl_fac_list & 0x01000000) {
54 		/* More facility bits available with stfle */
55 		register unsigned long reg0 asm("0") = size - 1;
56 
57 		asm volatile(".insn s,0xb2b00000,0(%1)" /* stfle */
58 			     : "+d" (reg0)
59 			     : "a" (stfle_fac_list)
60 			     : "memory", "cc");
61 		nr = (reg0 + 1) * 8; /* # bytes stored by stfle */
62 	}
63 	memset((char *) stfle_fac_list + nr, 0, size * 8 - nr);
64 	preempt_enable();
65 }
66 
67 #endif /* __ASM_FACILITY_H */
68