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  * Execute diagnose 0c in 31 bit mode
  20  */
  21 static void diag0c(struct hypfs_diag0c_entry *entry)
  22 {
  23         diag_stat_inc(DIAG_STAT_X00C);
  24         asm volatile (
  25                 "       sam31\n"
  26                 "       diag    %0,%0,0x0c\n"
  27                 "       sam64\n"
  28                 : /* no output register */
  29                 : "a" (entry)
  30                 : "memory");
  31 }
  32
  33 /*
  34  * Get hypfs_diag0c_entry from CPU vector and store diag0c data
  35  */
  36 static void diag0c_fn(void *data)
  37 {
  38         diag0c(((void **) data)[smp_processor_id()]);
  39 }
  40
  41 /*
  42  * Allocate buffer and store diag 0c data
  43  */
  44 static void *diag0c_store(unsigned int *count)
  45 {
  46         struct hypfs_diag0c_data *diag0c_data;
  47         unsigned int cpu_count, cpu, i;
  48         void **cpu_vec;
  49
  50         get_online_cpus();
  51         cpu_count = num_online_cpus();
  52         cpu_vec = kmalloc_array(num_possible_cpus(), sizeof(*cpu_vec),
  53                                 GFP_KERNEL);
  54         if (!cpu_vec)
  55                 goto fail_put_online_cpus;
  56         /* Note: Diag 0c needs 8 byte alignment and real storage */
  57         diag0c_data = kzalloc(sizeof(struct hypfs_diag0c_hdr) +
  58                               cpu_count * sizeof(struct hypfs_diag0c_entry),
  59                               GFP_KERNEL | GFP_DMA);
  60         if (!diag0c_data)
  61                 goto fail_kfree_cpu_vec;
  62         i = 0;
  63         /* Fill CPU vector for each online CPU */
  64         for_each_online_cpu(cpu) {
  65                 diag0c_data->entry[i].cpu = cpu;
  66                 cpu_vec[cpu] = &diag0c_data->entry[i++];
  67         }
  68         /* Collect data all CPUs */
  69         on_each_cpu(diag0c_fn, cpu_vec, 1);
  70         *count = cpu_count;
  71         kfree(cpu_vec);
  72         put_online_cpus();
  73         return diag0c_data;
  74
  75 fail_kfree_cpu_vec:
  76         kfree(cpu_vec);
  77 fail_put_online_cpus:
  78         put_online_cpus();
  79         return ERR_PTR(-ENOMEM);
  80 }
  81
  82 /*
  83  * Hypfs DBFS callback: Free diag 0c data
  84  */
  85 static void dbfs_diag0c_free(const void *data)
  86 {
  87         kfree(data);
  88 }
  89
  90 /*
  91  * Hypfs DBFS callback: Create diag 0c data
  92  */
  93 static int dbfs_diag0c_create(void **data, void **data_free_ptr, size_t *size)
  94 {
  95         struct hypfs_diag0c_data *diag0c_data;
  96         unsigned int count;
  97
  98         diag0c_data = diag0c_store(&count);
  99         if (IS_ERR(diag0c_data))
 100                 return PTR_ERR(diag0c_data);
 101         memset(&diag0c_data->hdr, 0, sizeof(diag0c_data->hdr));
 102         get_tod_clock_ext(diag0c_data->hdr.tod_ext);
 103         diag0c_data->hdr.len = count * sizeof(struct hypfs_diag0c_entry);
 104         diag0c_data->hdr.version = DBFS_D0C_HDR_VERSION;
 105         diag0c_data->hdr.count = count;
 106         *data = diag0c_data;
 107         *data_free_ptr = diag0c_data;
 108         *size = diag0c_data->hdr.len + sizeof(struct hypfs_diag0c_hdr);
 109         return 0;
 110 }
 111
 112 /*
 113  * Hypfs DBFS file structure
 114  */
 115 static struct hypfs_dbfs_file dbfs_file_0c = {
 116         .name           = "diag_0c",
 117         .data_create    = dbfs_diag0c_create,
 118         .data_free      = dbfs_diag0c_free,
 119 };
 120
 121 /*
 122  * Initialize diag 0c interface for z/VM
 123  */
 124 int __init hypfs_diag0c_init(void)
 125 {
 126         if (!MACHINE_IS_VM)
 127                 return 0;
 128         return hypfs_dbfs_create_file(&dbfs_file_0c);
 129 }
 130
 131 /*
 132  * Shutdown diag 0c interface for z/VM
 133  */
 134 void hypfs_diag0c_exit(void)
 135 {
 136         if (!MACHINE_IS_VM)
 137                 return;
 138         hypfs_dbfs_remove_file(&dbfs_file_0c);
 139 }