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  */
diag0c_fn(void * data)21 static void diag0c_fn(void *data)
22 {
23 	diag_stat_inc(DIAG_STAT_X00C);
24 	diag_amode31_ops.diag0c(((void **)data)[smp_processor_id()]);
25 }
26 
27 /*
28  * Allocate buffer and store diag 0c data
29  */
diag0c_store(unsigned int * count)30 static void *diag0c_store(unsigned int *count)
31 {
32 	struct hypfs_diag0c_data *diag0c_data;
33 	unsigned int cpu_count, cpu, i;
34 	void **cpu_vec;
35 
36 	cpus_read_lock();
37 	cpu_count = num_online_cpus();
38 	cpu_vec = kmalloc_array(num_possible_cpus(), sizeof(*cpu_vec),
39 				GFP_KERNEL);
40 	if (!cpu_vec)
41 		goto fail_unlock_cpus;
42 	/* Note: Diag 0c needs 8 byte alignment and real storage */
43 	diag0c_data = kzalloc(struct_size(diag0c_data, entry, cpu_count),
44 			      GFP_KERNEL | GFP_DMA);
45 	if (!diag0c_data)
46 		goto fail_kfree_cpu_vec;
47 	i = 0;
48 	/* Fill CPU vector for each online CPU */
49 	for_each_online_cpu(cpu) {
50 		diag0c_data->entry[i].cpu = cpu;
51 		cpu_vec[cpu] = &diag0c_data->entry[i++];
52 	}
53 	/* Collect data all CPUs */
54 	on_each_cpu(diag0c_fn, cpu_vec, 1);
55 	*count = cpu_count;
56 	kfree(cpu_vec);
57 	cpus_read_unlock();
58 	return diag0c_data;
59 
60 fail_kfree_cpu_vec:
61 	kfree(cpu_vec);
62 fail_unlock_cpus:
63 	cpus_read_unlock();
64 	return ERR_PTR(-ENOMEM);
65 }
66 
67 /*
68  * Hypfs DBFS callback: Free diag 0c data
69  */
dbfs_diag0c_free(const void * data)70 static void dbfs_diag0c_free(const void *data)
71 {
72 	kfree(data);
73 }
74 
75 /*
76  * Hypfs DBFS callback: Create diag 0c data
77  */
dbfs_diag0c_create(void ** data,void ** data_free_ptr,size_t * size)78 static int dbfs_diag0c_create(void **data, void **data_free_ptr, size_t *size)
79 {
80 	struct hypfs_diag0c_data *diag0c_data;
81 	unsigned int count;
82 
83 	diag0c_data = diag0c_store(&count);
84 	if (IS_ERR(diag0c_data))
85 		return PTR_ERR(diag0c_data);
86 	memset(&diag0c_data->hdr, 0, sizeof(diag0c_data->hdr));
87 	store_tod_clock_ext((union tod_clock *)diag0c_data->hdr.tod_ext);
88 	diag0c_data->hdr.len = count * sizeof(struct hypfs_diag0c_entry);
89 	diag0c_data->hdr.version = DBFS_D0C_HDR_VERSION;
90 	diag0c_data->hdr.count = count;
91 	*data = diag0c_data;
92 	*data_free_ptr = diag0c_data;
93 	*size = diag0c_data->hdr.len + sizeof(struct hypfs_diag0c_hdr);
94 	return 0;
95 }
96 
97 /*
98  * Hypfs DBFS file structure
99  */
100 static struct hypfs_dbfs_file dbfs_file_0c = {
101 	.name		= "diag_0c",
102 	.data_create	= dbfs_diag0c_create,
103 	.data_free	= dbfs_diag0c_free,
104 };
105 
106 /*
107  * Initialize diag 0c interface for z/VM
108  */
hypfs_diag0c_init(void)109 int __init hypfs_diag0c_init(void)
110 {
111 	if (!MACHINE_IS_VM)
112 		return 0;
113 	hypfs_dbfs_create_file(&dbfs_file_0c);
114 	return 0;
115 }
116 
117 /*
118  * Shutdown diag 0c interface for z/VM
119  */
hypfs_diag0c_exit(void)120 void hypfs_diag0c_exit(void)
121 {
122 	if (!MACHINE_IS_VM)
123 		return;
124 	hypfs_dbfs_remove_file(&dbfs_file_0c);
125 }
126