arch/s390/hypfs/hypfs_diag0c.c

   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         diag_stat_inc(DIAG_STAT_X00C);
  24         diag_dma_ops.diag0c(((void **) data)[smp_processor_id()]);
  25 }
  26
  27 /*
  28  * Allocate buffer and store diag 0c data
  29  */
  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         get_online_cpus();
  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_put_online_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         put_online_cpus();
  58         return diag0c_data;
  59
  60 fail_kfree_cpu_vec:
  61         kfree(cpu_vec);
  62 fail_put_online_cpus:
  63         put_online_cpus();
  64         return ERR_PTR(-ENOMEM);
  65 }
  66
  67 /*
  68  * Hypfs DBFS callback: Free diag 0c data
  69  */
  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  */
  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         get_tod_clock_ext(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  */
 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  */
 120 void hypfs_diag0c_exit(void)
 121 {
 122         if (!MACHINE_IS_VM)
 123                 return;
 124         hypfs_dbfs_remove_file(&dbfs_file_0c);
 125 }