LXR linux/arch/s390/hypfs/hypfs

   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 */
  21static 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 */
  36static 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 */
  44static 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
  75fail_kfree_cpu_vec:
  76        kfree(cpu_vec);
  77fail_put_online_cpus:
  78        put_online_cpus();
  79        return ERR_PTR(-ENOMEM);
  80}
  81
  82/*
  83 * Hypfs DBFS callback: Free diag 0c data
  84 */
  85static void dbfs_diag0c_free(const void *data)
  86{
  87        kfree(data);
  88}
  89
  90/*
  91 * Hypfs DBFS callback: Create diag 0c data
  92 */
  93static 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 */
 115static 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 */
 124int __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 */
 134void hypfs_diag0c_exit(void)
 135{
 136        if (!MACHINE_IS_VM)
 137                return;
 138        hypfs_dbfs_remove_file(&dbfs_file_0c);
 139}
 140