1 // SPDX-License-Identifier: GPL-2.0
2 #include <asm/byteorder.h>
3 #include <asm/lppaca.h>
4
5 /*
6 * The associativity domain numbers are returned from the hypervisor as a
7 * stream of mixed 16-bit and 32-bit fields. The stream is terminated by the
8 * special value of "all ones" (aka. 0xffff) and its size may not exceed 48
9 * bytes.
10 *
11 * --- 16-bit fields -->
12 * _________________________
13 * | 0 | 1 | 2 | 3 | be_packed[0]
14 * ------+-----+-----+------
15 * _________________________
16 * | 4 | 5 | 6 | 7 | be_packed[1]
17 * -------------------------
18 * ...
19 * _________________________
20 * | 20 | 21 | 22 | 23 | be_packed[5]
21 * -------------------------
22 *
23 * Convert to the sequence they would appear in the ibm,associativity property.
24 */
25 static int vphn_unpack_associativity(const long *packed, __be32 *unpacked)
26 {
27 __be64 be_packed[VPHN_REGISTER_COUNT];
28 int i, nr_assoc_doms = 0;
29 const __be16 *field = (const __be16 *) be_packed;
30 u16 last = 0;
31 bool is_32bit = false;
32
33 #define VPHN_FIELD_UNUSED (0xffff)
34 #define VPHN_FIELD_MSB (0x8000)
35 #define VPHN_FIELD_MASK (~VPHN_FIELD_MSB)
36
37 /* Let's fix the values returned by plpar_hcall9() */
38 for (i = 0; i < VPHN_REGISTER_COUNT; i++)
39 be_packed[i] = cpu_to_be64(packed[i]);
40
41 for (i = 1; i < VPHN_ASSOC_BUFSIZE; i++) {
42 u16 new = be16_to_cpup(field++);
43
44 if (is_32bit) {
45 /*
46 * Let's concatenate the 16 bits of this field to the
47 * 15 lower bits of the previous field
48 */
49 unpacked[++nr_assoc_doms] =
50 cpu_to_be32(last << 16 | new);
51 is_32bit = false;
52 } else if (new == VPHN_FIELD_UNUSED)
53 /* This is the list terminator */
54 break;
55 else if (new & VPHN_FIELD_MSB) {
56 /* Data is in the lower 15 bits of this field */
57 unpacked[++nr_assoc_doms] =
58 cpu_to_be32(new & VPHN_FIELD_MASK);
59 } else {
60 /*
61 * Data is in the lower 15 bits of this field
62 * concatenated with the next 16 bit field
63 */
64 last = new;
65 is_32bit = true;
66 }
67 }
68
69 /* The first cell contains the length of the property */
70 unpacked[0] = cpu_to_be32(nr_assoc_doms);
71
72 return nr_assoc_doms;
73 }
74
75 /* NOTE: This file is included by a selftest and built in userspace. */
76 #ifdef __KERNEL__
77 #include <asm/hvcall.h>
78
79 long hcall_vphn(unsigned long cpu, u64 flags, __be32 *associativity)
80 {
81 long rc;
82 long retbuf[PLPAR_HCALL9_BUFSIZE] = {0};
83
84 rc = plpar_hcall9(H_HOME_NODE_ASSOCIATIVITY, retbuf, flags, cpu);
85 vphn_unpack_associativity(retbuf, associativity);
86
87 return rc;
88 }
89 #endif