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/diag.h>
  12 #include <asm/hypfs.h>
  13 #include "hypfs.h"
  14
  15 #define DBFS_D0C_HDR_VERSION 0
  16
  17 /*
  18  * Execute diagnose 0c in 31 bit mode
  19  */
  20 static void diag0c(struct hypfs_diag0c_entry *entry)
  21 {
  22         diag_stat_inc(DIAG_STAT_X00C);
  23         asm volatile (
  24                 "       sam31\n"
  25                 "       diag    %0,%0,0x0c\n"
  26                 "       sam64\n"
  27                 : /* no output register */
  28                 : "a" (entry)
  29                 : "memory");
  30 }
  31
  32 /*
  33  * Get hypfs_diag0c_entry from CPU vector and store diag0c data
  34  */
  35 static void diag0c_fn(void *data)
  36 {
  37         diag0c(((void **) data)[smp_processor_id()]);
  38 }
  39
  40 /*
  41  * Allocate buffer and store diag 0c data
  42  */
  43 static void *diag0c_store(unsigned int *count)
  44 {
  45         struct hypfs_diag0c_data *diag0c_data;
  46         unsigned int cpu_count, cpu, i;
  47         void **cpu_vec;
  48
  49         get_online_cpus();
  50         cpu_count = num_online_cpus();
  51         cpu_vec = kmalloc(sizeof(*cpu_vec) * num_possible_cpus(), GFP_KERNEL);
  52         if (!cpu_vec)
  53                 goto fail_put_online_cpus;
  54         /* Note: Diag 0c needs 8 byte alignment and real storage */
  55         diag0c_data = kzalloc(sizeof(struct hypfs_diag0c_hdr) +
  56                               cpu_count * sizeof(struct hypfs_diag0c_entry),
  57                               GFP_KERNEL | GFP_DMA);
  58         if (!diag0c_data)
  59                 goto fail_kfree_cpu_vec;
  60         i = 0;
  61         /* Fill CPU vector for each online CPU */
  62         for_each_online_cpu(cpu) {
  63                 diag0c_data->entry[i].cpu = cpu;
  64                 cpu_vec[cpu] = &diag0c_data->entry[i++];
  65         }
  66         /* Collect data all CPUs */
  67         on_each_cpu(diag0c_fn, cpu_vec, 1);
  68         *count = cpu_count;
  69         kfree(cpu_vec);
  70         put_online_cpus();
  71         return diag0c_data;
  72
  73 fail_kfree_cpu_vec:
  74         kfree(cpu_vec);
  75 fail_put_online_cpus:
  76         put_online_cpus();
  77         return ERR_PTR(-ENOMEM);
  78 }
  79
  80 /*
  81  * Hypfs DBFS callback: Free diag 0c data
  82  */
  83 static void dbfs_diag0c_free(const void *data)
  84 {
  85         kfree(data);
  86 }
  87
  88 /*
  89  * Hypfs DBFS callback: Create diag 0c data
  90  */
  91 static int dbfs_diag0c_create(void **data, void **data_free_ptr, size_t *size)
  92 {
  93         struct hypfs_diag0c_data *diag0c_data;
  94         unsigned int count;
  95
  96         diag0c_data = diag0c_store(&count);
  97         if (IS_ERR(diag0c_data))
  98                 return PTR_ERR(diag0c_data);
  99         memset(&diag0c_data->hdr, 0, sizeof(diag0c_data->hdr));
 100         get_tod_clock_ext(diag0c_data->hdr.tod_ext);
 101         diag0c_data->hdr.len = count * sizeof(struct hypfs_diag0c_entry);
 102         diag0c_data->hdr.version = DBFS_D0C_HDR_VERSION;
 103         diag0c_data->hdr.count = count;
 104         *data = diag0c_data;
 105         *data_free_ptr = diag0c_data;
 106         *size = diag0c_data->hdr.len + sizeof(struct hypfs_diag0c_hdr);
 107         return 0;
 108 }
 109
 110 /*
 111  * Hypfs DBFS file structure
 112  */
 113 static struct hypfs_dbfs_file dbfs_file_0c = {
 114         .name           = "diag_0c",
 115         .data_create    = dbfs_diag0c_create,
 116         .data_free      = dbfs_diag0c_free,
 117 };
 118
 119 /*
 120  * Initialize diag 0c interface for z/VM
 121  */
 122 int __init hypfs_diag0c_init(void)
 123 {
 124         if (!MACHINE_IS_VM)
 125                 return 0;
 126         return hypfs_dbfs_create_file(&dbfs_file_0c);
 127 }
 128
 129 /*
 130  * Shutdown diag 0c interface for z/VM
 131  */
 132 void hypfs_diag0c_exit(void)
 133 {
 134         if (!MACHINE_IS_VM)
 135                 return;
 136         hypfs_dbfs_remove_file(&dbfs_file_0c);
 137 }