| 1 | // SPDX-License-Identifier: GPL-2.0 |
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| 2 | #include <asm/byteorder.h> |
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| 3 | #include <asm/vphn.h> |
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| 4 | |
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| 5 | /* |
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| 6 | * The associativity domain numbers are returned from the hypervisor as a |
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| 7 | * stream of mixed 16-bit and 32-bit fields. The stream is terminated by the |
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| 8 | * special value of "all ones" (aka. 0xffff) and its size may not exceed 48 |
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| 9 | * bytes. |
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| 10 | * |
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| 11 | * --- 16-bit fields --> |
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| 12 | * _________________________ |
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| 13 | * | 0 | 1 | 2 | 3 | be_packed[0] |
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| 14 | * ------+-----+-----+------ |
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| 15 | * _________________________ |
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| 16 | * | 4 | 5 | 6 | 7 | be_packed[1] |
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| 17 | * ------------------------- |
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| 18 | * ... |
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| 19 | * _________________________ |
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| 20 | * | 20 | 21 | 22 | 23 | be_packed[5] |
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| 21 | * ------------------------- |
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| 22 | * |
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| 23 | * Convert to the sequence they would appear in the ibm,associativity property. |
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| 24 | */ |
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| 25 | static int vphn_unpack_associativity(const long *packed, __be32 *unpacked) |
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| 26 | { |
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| 27 | __be64 be_packed[VPHN_REGISTER_COUNT]; |
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| 28 | int i, nr_assoc_doms = 0; |
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| 29 | const __be16 *field = (const __be16 *) be_packed; |
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| 30 | u16 last = 0; |
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| 31 | bool is_32bit = false; |
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| 32 | |
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| 33 | #define VPHN_FIELD_UNUSED (0xffff) |
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| 34 | #define VPHN_FIELD_MSB (0x8000) |
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| 35 | #define VPHN_FIELD_MASK (~VPHN_FIELD_MSB) |
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| 36 | |
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| 37 | /* Let's fix the values returned by plpar_hcall9() */ |
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| 38 | for (i = 0; i < VPHN_REGISTER_COUNT; i++) |
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| 39 | be_packed[i] = cpu_to_be64(packed[i]); |
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| 40 | |
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| 41 | for (i = 1; i < VPHN_ASSOC_BUFSIZE; i++) { |
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| 42 | u16 new = be16_to_cpup(field++); |
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| 43 | |
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| 44 | if (is_32bit) { |
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| 45 | /* |
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| 46 | * Let's concatenate the 16 bits of this field to the |
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| 47 | * 15 lower bits of the previous field |
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| 48 | */ |
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| 49 | unpacked[++nr_assoc_doms] = |
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| 50 | cpu_to_be32(last << 16 | new); |
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| 51 | is_32bit = false; |
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| 52 | } else if (new == VPHN_FIELD_UNUSED) |
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| 53 | /* This is the list terminator */ |
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| 54 | break; |
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| 55 | else if (new & VPHN_FIELD_MSB) { |
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| 56 | /* Data is in the lower 15 bits of this field */ |
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| 57 | unpacked[++nr_assoc_doms] = |
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| 58 | cpu_to_be32(new & VPHN_FIELD_MASK); |
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| 59 | } else { |
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| 60 | /* |
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| 61 | * Data is in the lower 15 bits of this field |
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| 62 | * concatenated with the next 16 bit field |
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| 63 | */ |
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| 64 | last = new; |
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| 65 | is_32bit = true; |
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| 66 | } |
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| 67 | } |
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| 68 | |
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| 69 | /* The first cell contains the length of the property */ |
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| 70 | unpacked[0] = cpu_to_be32(nr_assoc_doms); |
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| 71 | |
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| 72 | return nr_assoc_doms; |
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| 73 | } |
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| 74 | |
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| 75 | /* NOTE: This file is included by a selftest and built in userspace. */ |
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| 76 | #ifdef __KERNEL__ |
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| 77 | #include <asm/hvcall.h> |
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| 78 | |
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| 79 | long hcall_vphn(unsigned long cpu, u64 flags, __be32 *associativity) |
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| 80 | { |
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| 81 | long rc; |
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| 82 | long retbuf[PLPAR_HCALL9_BUFSIZE] = {0}; |
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| 83 | |
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| 84 | rc = plpar_hcall9(H_HOME_NODE_ASSOCIATIVITY, retbuf, flags, cpu); |
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| 85 | if (rc == H_SUCCESS) |
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| 86 | vphn_unpack_associativity(packed: retbuf, unpacked: associativity); |
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| 87 | |
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| 88 | return rc; |
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| 89 | } |
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| 90 | #endif |
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| 91 | |
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