drivers/s390/char/diag_ftp.c

   1 /*
   2  *    DIAGNOSE X'2C4' instruction based HMC FTP services, useable on z/VM
   3  *
   4  *    Copyright IBM Corp. 2013
   5  *    Author(s): Ralf Hoppe (rhoppe@de.ibm.com)
   6  *
   7  */
   8
   9 #define KMSG_COMPONENT "hmcdrv"
  10 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  11
  12 #include <linux/kernel.h>
  13 #include <linux/mm.h>
  14 #include <linux/irq.h>
  15 #include <linux/wait.h>
  16 #include <linux/string.h>
  17 #include <asm/ctl_reg.h>
  18
  19 #include "hmcdrv_ftp.h"
  20 #include "diag_ftp.h"
  21
  22 /* DIAGNOSE X'2C4' return codes in Ry */
  23 #define DIAG_FTP_RET_OK 0 /* HMC FTP started successfully */
  24 #define DIAG_FTP_RET_EBUSY      4 /* HMC FTP service currently busy */
  25 #define DIAG_FTP_RET_EIO        8 /* HMC FTP service I/O error */
  26 /* and an artificial extension */
  27 #define DIAG_FTP_RET_EPERM      2 /* HMC FTP service privilege error */
  28
  29 /* FTP service status codes (after INTR at guest real location 133) */
  30 #define DIAG_FTP_STAT_OK        0U /* request completed successfully */
  31 #define DIAG_FTP_STAT_PGCC      4U /* program check condition */
  32 #define DIAG_FTP_STAT_PGIOE     8U /* paging I/O error */
  33 #define DIAG_FTP_STAT_TIMEOUT   12U /* timeout */
  34 #define DIAG_FTP_STAT_EBASE     16U /* base of error codes from SCLP */
  35 #define DIAG_FTP_STAT_LDFAIL    (DIAG_FTP_STAT_EBASE + 1U) /* failed */
  36 #define DIAG_FTP_STAT_LDNPERM   (DIAG_FTP_STAT_EBASE + 2U) /* not allowed */
  37 #define DIAG_FTP_STAT_LDRUNS    (DIAG_FTP_STAT_EBASE + 3U) /* runs */
  38 #define DIAG_FTP_STAT_LDNRUNS   (DIAG_FTP_STAT_EBASE + 4U) /* not runs */
  39
  40 /**
  41  * struct diag_ftp_ldfpl - load file FTP parameter list (LDFPL)
  42  * @bufaddr: real buffer address (at 4k boundary)
  43  * @buflen: length of buffer
  44  * @offset: dir/file offset
  45  * @intparm: interruption parameter (unused)
  46  * @transferred: bytes transferred
  47  * @fsize: file size, filled on GET
  48  * @failaddr: failing address
  49  * @spare: padding
  50  * @fident: file name - ASCII
  51  */
  52 struct diag_ftp_ldfpl {
  53         u64 bufaddr;
  54         u64 buflen;
  55         u64 offset;
  56         u64 intparm;
  57         u64 transferred;
  58         u64 fsize;
  59         u64 failaddr;
  60         u64 spare;
  61         u8 fident[HMCDRV_FTP_FIDENT_MAX];
  62 } __packed;
  63
  64 static DECLARE_COMPLETION(diag_ftp_rx_complete);
  65 static int diag_ftp_subcode;
  66
  67 /**
  68  * diag_ftp_handler() - FTP services IRQ handler
  69  * @extirq: external interrupt (sub-) code
  70  * @param32: 32-bit interruption parameter from &struct diag_ftp_ldfpl
  71  * @param64: unused (for 64-bit interrupt parameters)
  72  */
  73 static void diag_ftp_handler(struct ext_code extirq,
  74                              unsigned int param32,
  75                              unsigned long param64)
  76 {
  77         if ((extirq.subcode >> 8) != 8)
  78                 return; /* not a FTP services sub-code */
  79
  80         inc_irq_stat(IRQEXT_FTP);
  81         diag_ftp_subcode = extirq.subcode & 0xffU;
  82         complete(&diag_ftp_rx_complete);
  83 }
  84
  85 /**
  86  * diag_ftp_2c4() - DIAGNOSE X'2C4' service call
  87  * @fpl: pointer to prepared LDFPL
  88  * @cmd: FTP command to be executed
  89  *
  90  * Performs a DIAGNOSE X'2C4' call with (input/output) FTP parameter list
  91  * @fpl and FTP function code @cmd. In case of an error the function does
  92  * nothing and returns an (negative) error code.
  93  *
  94  * Notes:
  95  * 1. This function only initiates a transfer, so the caller must wait
  96  *    for completion (asynchronous execution).
  97  * 2. The FTP parameter list @fpl must be aligned to a double-word boundary.
  98  * 3. fpl->bufaddr must be a real address, 4k aligned
  99  */
 100 static int diag_ftp_2c4(struct diag_ftp_ldfpl *fpl,
 101                         enum hmcdrv_ftp_cmdid cmd)
 102 {
 103         int rc;
 104
 105         asm volatile(
 106                 "       diag    %[addr],%[cmd],0x2c4\n"
 107                 "0:     j       2f\n"
 108                 "1:     la      %[rc],%[err]\n"
 109                 "2:\n"
 110                 EX_TABLE(0b, 1b)
 111                 : [rc] "=d" (rc), "+m" (*fpl)
 112                 : [cmd] "0" (cmd), [addr] "d" (virt_to_phys(fpl)),
 113                   [err] "i" (DIAG_FTP_RET_EPERM)
 114                 : "cc");
 115
 116         switch (rc) {
 117         case DIAG_FTP_RET_OK:
 118                 return 0;
 119         case DIAG_FTP_RET_EBUSY:
 120                 return -EBUSY;
 121         case DIAG_FTP_RET_EPERM:
 122                 return -EPERM;
 123         case DIAG_FTP_RET_EIO:
 124         default:
 125                 return -EIO;
 126         }
 127 }
 128
 129 /**
 130  * diag_ftp_cmd() - executes a DIAG X'2C4' FTP command, targeting a HMC
 131  * @ftp: pointer to FTP command specification
 132  * @fsize: return of file size (or NULL if undesirable)
 133  *
 134  * Attention: Notice that this function is not reentrant - so the caller
 135  * must ensure locking.
 136  *
 137  * Return: number of bytes read/written or a (negative) error code
 138  */
 139 ssize_t diag_ftp_cmd(const struct hmcdrv_ftp_cmdspec *ftp, size_t *fsize)
 140 {
 141         struct diag_ftp_ldfpl *ldfpl;
 142         ssize_t len;
 143 #ifdef DEBUG
 144         unsigned long start_jiffies;
 145
 146         pr_debug("starting DIAG X'2C4' on '%s', requesting %zd bytes\n",
 147                  ftp->fname, ftp->len);
 148         start_jiffies = jiffies;
 149 #endif
 150         init_completion(&diag_ftp_rx_complete);
 151
 152         ldfpl = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
 153         if (!ldfpl) {
 154                 len = -ENOMEM;
 155                 goto out;
 156         }
 157
 158         len = strlcpy(ldfpl->fident, ftp->fname, sizeof(ldfpl->fident));
 159         if (len >= HMCDRV_FTP_FIDENT_MAX) {
 160                 len = -EINVAL;
 161                 goto out_free;
 162         }
 163
 164         ldfpl->transferred = 0;
 165         ldfpl->fsize = 0;
 166         ldfpl->offset = ftp->ofs;
 167         ldfpl->buflen = ftp->len;
 168         ldfpl->bufaddr = virt_to_phys(ftp->buf);
 169
 170         len = diag_ftp_2c4(ldfpl, ftp->id);
 171         if (len)
 172                 goto out_free;
 173
 174         /*
 175          * There is no way to cancel the running diag X'2C4', the code
 176          * needs to wait unconditionally until the transfer is complete.
 177          */
 178         wait_for_completion(&diag_ftp_rx_complete);
 179
 180 #ifdef DEBUG
 181         pr_debug("completed DIAG X'2C4' after %lu ms\n",
 182                  (jiffies - start_jiffies) * 1000 / HZ);
 183         pr_debug("status of DIAG X'2C4' is %u, with %lld/%lld bytes\n",
 184                  diag_ftp_subcode, ldfpl->transferred, ldfpl->fsize);
 185 #endif
 186
 187         switch (diag_ftp_subcode) {
 188         case DIAG_FTP_STAT_OK: /* success */
 189                 len = ldfpl->transferred;
 190                 if (fsize)
 191                         *fsize = ldfpl->fsize;
 192                 break;
 193         case DIAG_FTP_STAT_LDNPERM:
 194                 len = -EPERM;
 195                 break;
 196         case DIAG_FTP_STAT_LDRUNS:
 197                 len = -EBUSY;
 198                 break;
 199         case DIAG_FTP_STAT_LDFAIL:
 200                 len = -ENOENT; /* no such file or media */
 201                 break;
 202         default:
 203                 len = -EIO;
 204                 break;
 205         }
 206
 207 out_free:
 208         free_page((unsigned long) ldfpl);
 209 out:
 210         return len;
 211 }
 212
 213 /**
 214  * diag_ftp_startup() - startup of FTP services, when running on z/VM
 215  *
 216  * Return: 0 on success, else an (negative) error code
 217  */
 218 int diag_ftp_startup(void)
 219 {
 220         int rc;
 221
 222         rc = register_external_irq(EXT_IRQ_CP_SERVICE, diag_ftp_handler);
 223         if (rc)
 224                 return rc;
 225
 226         irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
 227         return 0;
 228 }
 229
 230 /**
 231  * diag_ftp_shutdown() - shutdown of FTP services, when running on z/VM
 232  */
 233 void diag_ftp_shutdown(void)
 234 {
 235         irq_subclass_unregister(IRQ_SUBCLASS_SERVICE_SIGNAL);
 236         unregister_external_irq(EXT_IRQ_CP_SERVICE, diag_ftp_handler);
 237 }