xref: /linux/arch/s390/include/asm/facility.h (revision 0d456bad36d42d16022be045c8a53ddbb59ee478)
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 /*
17  * The test_facility function uses the bit odering where the MSB is bit 0.
18  * That makes it easier to query facility bits with the bit number as
19  * documented in the Principles of Operation.
20  */
21 static inline int test_facility(unsigned long nr)
22 {
23 	unsigned char *ptr;
24 
25 	if (nr >= MAX_FACILITY_BIT)
26 		return 0;
27 	ptr = (unsigned char *) &S390_lowcore.stfle_fac_list + (nr >> 3);
28 	return (*ptr & (0x80 >> (nr & 7))) != 0;
29 }
30 
31 /**
32  * stfle - Store facility list extended
33  * @stfle_fac_list: array where facility list can be stored
34  * @size: size of passed in array in double words
35  */
36 static inline void stfle(u64 *stfle_fac_list, int size)
37 {
38 	unsigned long nr;
39 
40 	preempt_disable();
41 	asm volatile(
42 		"	.insn s,0xb2b10000,0(0)\n" /* stfl */
43 		"0:\n"
44 		EX_TABLE(0b, 0b)
45 		: "+m" (S390_lowcore.stfl_fac_list));
46 	nr = 4; /* bytes stored by stfl */
47 	memcpy(stfle_fac_list, &S390_lowcore.stfl_fac_list, 4);
48 	if (S390_lowcore.stfl_fac_list & 0x01000000) {
49 		/* More facility bits available with stfle */
50 		register unsigned long reg0 asm("0") = size - 1;
51 
52 		asm volatile(".insn s,0xb2b00000,0(%1)" /* stfle */
53 			     : "+d" (reg0)
54 			     : "a" (stfle_fac_list)
55 			     : "memory", "cc");
56 		nr = (reg0 + 1) * 8; /* # bytes stored by stfle */
57 	}
58 	memset((char *) stfle_fac_list + nr, 0, size * 8 - nr);
59 	preempt_enable();
60 }
61 
62 #endif /* __ASM_FACILITY_H */
63