1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Hypervisor filesystem for Linux on s390
4 *
5 * Diag 0C implementation
6 *
7 * Copyright IBM Corp. 2014
8 */
9
10 #include <linux/slab.h>
11 #include <linux/cpu.h>
12 #include <asm/diag.h>
13 #include <asm/hypfs.h>
14 #include "hypfs.h"
15
16 #define DBFS_D0C_HDR_VERSION 0
17
18 /*
19 * Get hypfs_diag0c_entry from CPU vector and store diag0c data
20 */
21 static void diag0c_fn(void *data)
22 {
23 diag0c(((void **)data)[smp_processor_id()]);
24 }
25
26 /*
27 * Allocate buffer and store diag 0c data
28 */
29 static void *diag0c_store(unsigned int *count)
30 {
31 struct hypfs_diag0c_data *diag0c_data;
32 unsigned int cpu_count, cpu, i;
33 void **cpu_vec;
34
35 cpus_read_lock();
36 cpu_count = num_online_cpus();
37 cpu_vec = kmalloc_array(num_possible_cpus(), sizeof(*cpu_vec),
38 GFP_KERNEL);
39 if (!cpu_vec)
40 goto fail_unlock_cpus;
41 /* Note: Diag 0c needs 8 byte alignment and real storage */
42 diag0c_data = kzalloc(struct_size(diag0c_data, entry, cpu_count),
43 GFP_KERNEL | GFP_DMA);
44 if (!diag0c_data)
45 goto fail_kfree_cpu_vec;
46 i = 0;
47 /* Fill CPU vector for each online CPU */
48 for_each_online_cpu(cpu) {
49 diag0c_data->entry[i].cpu = cpu;
50 cpu_vec[cpu] = &diag0c_data->entry[i++];
51 }
52 /* Collect data all CPUs */
53 on_each_cpu(diag0c_fn, cpu_vec, 1);
54 *count = cpu_count;
55 kfree(cpu_vec);
56 cpus_read_unlock();
57 return diag0c_data;
58
59 fail_kfree_cpu_vec:
60 kfree(cpu_vec);
61 fail_unlock_cpus:
62 cpus_read_unlock();
63 return ERR_PTR(-ENOMEM);
64 }
65
66 /*
67 * Hypfs DBFS callback: Free diag 0c data
68 */
69 static void dbfs_diag0c_free(const void *data)
70 {
71 kfree(data);
72 }
73
74 /*
75 * Hypfs DBFS callback: Create diag 0c data
76 */
77 static int dbfs_diag0c_create(void **data, void **data_free_ptr, size_t *size)
78 {
79 struct hypfs_diag0c_data *diag0c_data;
80 unsigned int count;
81
82 diag0c_data = diag0c_store(&count);
83 if (IS_ERR(diag0c_data))
84 return PTR_ERR(diag0c_data);
85 memset(&diag0c_data->hdr, 0, sizeof(diag0c_data->hdr));
86 store_tod_clock_ext((union tod_clock *)diag0c_data->hdr.tod_ext);
87 diag0c_data->hdr.len = count * sizeof(struct hypfs_diag0c_entry);
88 diag0c_data->hdr.version = DBFS_D0C_HDR_VERSION;
89 diag0c_data->hdr.count = count;
90 *data = diag0c_data;
91 *data_free_ptr = diag0c_data;
92 *size = diag0c_data->hdr.len + sizeof(struct hypfs_diag0c_hdr);
93 return 0;
94 }
95
96 /*
97 * Hypfs DBFS file structure
98 */
99 static struct hypfs_dbfs_file dbfs_file_0c = {
100 .name = "diag_0c",
101 .data_create = dbfs_diag0c_create,
102 .data_free = dbfs_diag0c_free,
103 };
104
105 /*
106 * Initialize diag 0c interface for z/VM
107 */
108 int __init hypfs_diag0c_init(void)
109 {
110 if (!MACHINE_IS_VM)
111 return 0;
112 hypfs_dbfs_create_file(&dbfs_file_0c);
113 return 0;
114 }
115
116 /*
117 * Shutdown diag 0c interface for z/VM
118 */
119 void hypfs_diag0c_exit(void)
120 {
121 if (!MACHINE_IS_VM)
122 return;
123 hypfs_dbfs_remove_file(&dbfs_file_0c);
124 }
125
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