arch/s390/hypfs/hypfs_diag0c.c

   1 /*
   2  * Hypervisor filesystem for Linux on s390
   3  *
   4  * Diag 0C implementation
   5  *
   6  * Copyright IBM Corp. 2014
   7  */
   8
   9 #include <linux/slab.h>
  10 #include <linux/cpu.h>
  11 #include <asm/hypfs.h>
  12 #include "hypfs.h"
  13
  14 #define DBFS_D0C_HDR_VERSION 0
  15
  16 /*
  17  * Execute diagnose 0c in 31 bit mode
  18  */
  19 static void diag0c(struct hypfs_diag0c_entry *entry)
  20 {
  21         asm volatile (
  22                 "       sam31\n"
  23                 "       diag    %0,%0,0x0c\n"
  24                 "       sam64\n"
  25                 : /* no output register */
  26                 : "a" (entry)
  27                 : "memory");
  28 }
  29
  30 /*
  31  * Get hypfs_diag0c_entry from CPU vector and store diag0c data
  32  */
  33 static void diag0c_fn(void *data)
  34 {
  35         diag0c(((void **) data)[smp_processor_id()]);
  36 }
  37
  38 /*
  39  * Allocate buffer and store diag 0c data
  40  */
  41 static void *diag0c_store(unsigned int *count)
  42 {
  43         struct hypfs_diag0c_data *diag0c_data;
  44         unsigned int cpu_count, cpu, i;
  45         void **cpu_vec;
  46
  47         get_online_cpus();
  48         cpu_count = num_online_cpus();
  49         cpu_vec = kmalloc(sizeof(*cpu_vec) * num_possible_cpus(), GFP_KERNEL);
  50         if (!cpu_vec)
  51                 goto fail_put_online_cpus;
  52         /* Note: Diag 0c needs 8 byte alignment and real storage */
  53         diag0c_data = kzalloc(sizeof(struct hypfs_diag0c_hdr) +
  54                               cpu_count * sizeof(struct hypfs_diag0c_entry),
  55                               GFP_KERNEL | GFP_DMA);
  56         if (!diag0c_data)
  57                 goto fail_kfree_cpu_vec;
  58         i = 0;
  59         /* Fill CPU vector for each online CPU */
  60         for_each_online_cpu(cpu) {
  61                 diag0c_data->entry[i].cpu = cpu;
  62                 cpu_vec[cpu] = &diag0c_data->entry[i++];
  63         }
  64         /* Collect data all CPUs */
  65         on_each_cpu(diag0c_fn, cpu_vec, 1);
  66         *count = cpu_count;
  67         kfree(cpu_vec);
  68         put_online_cpus();
  69         return diag0c_data;
  70
  71 fail_kfree_cpu_vec:
  72         kfree(cpu_vec);
  73 fail_put_online_cpus:
  74         put_online_cpus();
  75         return ERR_PTR(-ENOMEM);
  76 }
  77
  78 /*
  79  * Hypfs DBFS callback: Free diag 0c data
  80  */
  81 static void dbfs_diag0c_free(const void *data)
  82 {
  83         kfree(data);
  84 }
  85
  86 /*
  87  * Hypfs DBFS callback: Create diag 0c data
  88  */
  89 static int dbfs_diag0c_create(void **data, void **data_free_ptr, size_t *size)
  90 {
  91         struct hypfs_diag0c_data *diag0c_data;
  92         unsigned int count;
  93
  94         diag0c_data = diag0c_store(&count);
  95         if (IS_ERR(diag0c_data))
  96                 return PTR_ERR(diag0c_data);
  97         memset(&diag0c_data->hdr, 0, sizeof(diag0c_data->hdr));
  98         get_tod_clock_ext(diag0c_data->hdr.tod_ext);
  99         diag0c_data->hdr.len = count * sizeof(struct hypfs_diag0c_entry);
 100         diag0c_data->hdr.version = DBFS_D0C_HDR_VERSION;
 101         diag0c_data->hdr.count = count;
 102         *data = diag0c_data;
 103         *data_free_ptr = diag0c_data;
 104         *size = diag0c_data->hdr.len + sizeof(struct hypfs_diag0c_hdr);
 105         return 0;
 106 }
 107
 108 /*
 109  * Hypfs DBFS file structure
 110  */
 111 static struct hypfs_dbfs_file dbfs_file_0c = {
 112         .name           = "diag_0c",
 113         .data_create    = dbfs_diag0c_create,
 114         .data_free      = dbfs_diag0c_free,
 115 };
 116
 117 /*
 118  * Initialize diag 0c interface for z/VM
 119  */
 120 int __init hypfs_diag0c_init(void)
 121 {
 122         if (!MACHINE_IS_VM)
 123                 return 0;
 124         return hypfs_dbfs_create_file(&dbfs_file_0c);
 125 }
 126
 127 /*
 128  * Shutdown diag 0c interface for z/VM
 129  */
 130 void hypfs_diag0c_exit(void)
 131 {
 132         if (!MACHINE_IS_VM)
 133                 return;
 134         hypfs_dbfs_remove_file(&dbfs_file_0c);
 135 }