arch/mips/kernel/kspd.c

   1 /*
   2  * Copyright (C) 2005 MIPS Technologies, Inc.  All rights reserved.
   3  *
   4  *  This program is free software; you can distribute it and/or modify it
   5  *  under the terms of the GNU General Public License (Version 2) as
   6  *  published by the Free Software Foundation.
   7  *
   8  *  This program is distributed in the hope it will be useful, but WITHOUT
   9  *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  11  *  for more details.
  12  *
  13  *  You should have received a copy of the GNU General Public License along
  14  *  with this program; if not, write to the Free Software Foundation, Inc.,
  15  *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
  16  *
  17  */
  18 #include <linux/kernel.h>
  19 #include <linux/module.h>
  20 #include <linux/unistd.h>
  21 #include <linux/file.h>
  22 #include <linux/fs.h>
  23 #include <linux/syscalls.h>
  24 #include <linux/workqueue.h>
  25 #include <linux/errno.h>
  26 #include <linux/list.h>
  27
  28 #include <asm/vpe.h>
  29 #include <asm/rtlx.h>
  30 #include <asm/kspd.h>
  31
  32 static struct workqueue_struct *workqueue = NULL;
  33 static struct work_struct work;
  34
  35 extern unsigned long cpu_khz;
  36
  37 struct mtsp_syscall {
  38         int cmd;
  39         unsigned char abi;
  40         unsigned char size;
  41 };
  42
  43 struct mtsp_syscall_ret {
  44         int retval;
  45         int errno;
  46 };
  47
  48 struct mtsp_syscall_generic {
  49         int arg0;
  50         int arg1;
  51         int arg2;
  52         int arg3;
  53         int arg4;
  54         int arg5;
  55         int arg6;
  56 };
  57
  58 static struct list_head kspd_notifylist;
  59 static int sp_stopping = 0;
  60
  61 /* these should match with those in the SDE kit */
  62 #define MTSP_SYSCALL_BASE       0
  63 #define MTSP_SYSCALL_EXIT       (MTSP_SYSCALL_BASE + 0)
  64 #define MTSP_SYSCALL_OPEN       (MTSP_SYSCALL_BASE + 1)
  65 #define MTSP_SYSCALL_READ       (MTSP_SYSCALL_BASE + 2)
  66 #define MTSP_SYSCALL_WRITE      (MTSP_SYSCALL_BASE + 3)
  67 #define MTSP_SYSCALL_CLOSE      (MTSP_SYSCALL_BASE + 4)
  68 #define MTSP_SYSCALL_LSEEK32    (MTSP_SYSCALL_BASE + 5)
  69 #define MTSP_SYSCALL_ISATTY     (MTSP_SYSCALL_BASE + 6)
  70 #define MTSP_SYSCALL_GETTIME    (MTSP_SYSCALL_BASE + 7)
  71 #define MTSP_SYSCALL_PIPEFREQ   (MTSP_SYSCALL_BASE + 8)
  72 #define MTSP_SYSCALL_GETTOD     (MTSP_SYSCALL_BASE + 9)
  73 #define MTSP_SYSCALL_IOCTL     (MTSP_SYSCALL_BASE + 10)
  74
  75 #define MTSP_O_RDONLY           0x0000
  76 #define MTSP_O_WRONLY           0x0001
  77 #define MTSP_O_RDWR             0x0002
  78 #define MTSP_O_NONBLOCK         0x0004
  79 #define MTSP_O_APPEND           0x0008
  80 #define MTSP_O_SHLOCK           0x0010
  81 #define MTSP_O_EXLOCK           0x0020
  82 #define MTSP_O_ASYNC            0x0040
  83 #define MTSP_O_FSYNC            O_SYNC
  84 #define MTSP_O_NOFOLLOW         0x0100
  85 #define MTSP_O_SYNC             0x0080
  86 #define MTSP_O_CREAT            0x0200
  87 #define MTSP_O_TRUNC            0x0400
  88 #define MTSP_O_EXCL             0x0800
  89 #define MTSP_O_BINARY           0x8000
  90
  91 #define SP_VPE 1
  92
  93 struct apsp_table  {
  94         int sp;
  95         int ap;
  96 };
  97
  98 /* we might want to do the mode flags too */
  99 struct apsp_table open_flags_table[] = {
 100         { MTSP_O_RDWR, O_RDWR },
 101         { MTSP_O_WRONLY, O_WRONLY },
 102         { MTSP_O_CREAT, O_CREAT },
 103         { MTSP_O_TRUNC, O_TRUNC },
 104         { MTSP_O_NONBLOCK, O_NONBLOCK },
 105         { MTSP_O_APPEND, O_APPEND },
 106         { MTSP_O_NOFOLLOW, O_NOFOLLOW }
 107 };
 108
 109 struct apsp_table syscall_command_table[] = {
 110         { MTSP_SYSCALL_OPEN, __NR_open },
 111         { MTSP_SYSCALL_CLOSE, __NR_close },
 112         { MTSP_SYSCALL_READ, __NR_read },
 113         { MTSP_SYSCALL_WRITE, __NR_write },
 114         { MTSP_SYSCALL_LSEEK32, __NR_lseek },
 115         { MTSP_SYSCALL_IOCTL, __NR_ioctl }
 116 };
 117
 118 static int sp_syscall(int num, int arg0, int arg1, int arg2, int arg3)
 119 {
 120         register long int _num  __asm__ ("$2") = num;
 121         register long int _arg0  __asm__ ("$4") = arg0;
 122         register long int _arg1  __asm__ ("$5") = arg1;
 123         register long int _arg2  __asm__ ("$6") = arg2;
 124         register long int _arg3  __asm__ ("$7") = arg3;
 125
 126         mm_segment_t old_fs;
 127
 128         old_fs = get_fs();
 129         set_fs(KERNEL_DS);
 130
 131         __asm__ __volatile__ (
 132         "       syscall                                 \n"
 133         : "=r" (_num), "=r" (_arg3)
 134         : "r" (_num), "r" (_arg0), "r" (_arg1), "r" (_arg2), "r" (_arg3));
 135
 136         set_fs(old_fs);
 137
 138         /* $a3 is error flag */
 139         if (_arg3)
 140                 return -_num;
 141
 142         return _num;
 143 }
 144
 145 static int translate_syscall_command(int cmd)
 146 {
 147         int i;
 148         int ret = -1;
 149
 150         for (i = 0; i < ARRAY_SIZE(syscall_command_table); i++) {
 151                 if ((cmd == syscall_command_table[i].sp))
 152                         return syscall_command_table[i].ap;
 153         }
 154
 155         return ret;
 156 }
 157
 158 static unsigned int translate_open_flags(int flags)
 159 {
 160         int i;
 161         unsigned int ret = 0;
 162
 163         for (i = 0; i < (sizeof(open_flags_table) / sizeof(struct apsp_table));
 164              i++) {
 165                 if( (flags & open_flags_table[i].sp) ) {
 166                         ret |= open_flags_table[i].ap;
 167                 }
 168         }
 169
 170         return ret;
 171 }
 172
 173
 174 static void sp_setfsuidgid( uid_t uid, gid_t gid)
 175 {
 176         current->fsuid = uid;
 177         current->fsgid = gid;
 178
 179         key_fsuid_changed(current);
 180         key_fsgid_changed(current);
 181 }
 182
 183 /*
 184  * Expects a request to be on the sysio channel. Reads it.  Decides whether
 185  * its a linux syscall and runs it, or whatever.  Puts the return code back
 186  * into the request and sends the whole thing back.
 187  */
 188 void sp_work_handle_request(void)
 189 {
 190         struct mtsp_syscall sc;
 191         struct mtsp_syscall_generic generic;
 192         struct mtsp_syscall_ret ret;
 193         struct kspd_notifications *n;
 194         unsigned long written;
 195         mm_segment_t old_fs;
 196         struct timeval tv;
 197         struct timezone tz;
 198         int cmd;
 199
 200         char *vcwd;
 201         mm_segment_t old_fs;
 202         int size;
 203
 204         ret.retval = -1;
 205
 206         old_fs = get_fs();
 207         set_fs(KERNEL_DS);
 208
 209         if (!rtlx_read(RTLX_CHANNEL_SYSIO, &sc, sizeof(struct mtsp_syscall))) {
 210                 set_fs(old_fs);
 211                 printk(KERN_ERR "Expected request but nothing to read\n");
 212                 return;
 213         }
 214
 215         size = sc.size;
 216
 217         if (size) {
 218                 if (!rtlx_read(RTLX_CHANNEL_SYSIO, &generic, size)) {
 219                         set_fs(old_fs);
 220                         printk(KERN_ERR "Expected request but nothing to read\n");
 221                         return;
 222                 }
 223         }
 224
 225         /* Run the syscall at the priviledge of the user who loaded the
 226            SP program */
 227
 228         if (vpe_getuid(SP_VPE))
 229                 sp_setfsuidgid( vpe_getuid(SP_VPE), vpe_getgid(SP_VPE));
 230
 231         switch (sc.cmd) {
 232         /* needs the flags argument translating from SDE kit to
 233            linux */
 234         case MTSP_SYSCALL_PIPEFREQ:
 235                 ret.retval = cpu_khz * 1000;
 236                 ret.errno = 0;
 237                 break;
 238
 239         case MTSP_SYSCALL_GETTOD:
 240                 memset(&tz, 0, sizeof(tz));
 241                 if ((ret.retval = sp_syscall(__NR_gettimeofday, (int)&tv,
 242                                              (int)&tz, 0,0)) == 0)
 243                 ret.retval = tv.tv_sec;
 244
 245                 ret.errno = errno;
 246                 break;
 247
 248         case MTSP_SYSCALL_EXIT:
 249                 list_for_each_entry(n, &kspd_notifylist, list)
 250                         n->kspd_sp_exit(SP_VPE);
 251                 sp_stopping = 1;
 252
 253                 printk(KERN_DEBUG "KSPD got exit syscall from SP exitcode %d\n",
 254                        generic.arg0);
 255                 break;
 256
 257         case MTSP_SYSCALL_OPEN:
 258                 generic.arg1 = translate_open_flags(generic.arg1);
 259
 260                 vcwd = vpe_getcwd(SP_VPE);
 261
 262                 /* change to the cwd of the process that loaded the SP program */
 263                 old_fs = get_fs();
 264                 set_fs(KERNEL_DS);
 265                 sys_chdir(vcwd);
 266                 set_fs(old_fs);
 267
 268                 sc.cmd = __NR_open;
 269
 270                 /* fall through */
 271
 272         default:
 273                 if ((sc.cmd >= __NR_Linux) &&
 274                     (sc.cmd <= (__NR_Linux +  __NR_Linux_syscalls)) )
 275                         cmd = sc.cmd;
 276                 else
 277                         cmd = translate_syscall_command(sc.cmd);
 278
 279                 if (cmd >= 0) {
 280                         ret.retval = sp_syscall(cmd, generic.arg0, generic.arg1,
 281                                                 generic.arg2, generic.arg3);
 282                         ret.errno = errno;
 283                 } else
 284                         printk(KERN_WARNING
 285                                "KSPD: Unknown SP syscall number %d\n", sc.cmd);
 286                 break;
 287         } /* switch */
 288
 289         if (vpe_getuid(SP_VPE))
 290                 sp_setfsuidgid( 0, 0);
 291
 292         old_fs = get_fs();
 293         set_fs(KERNEL_DS);
 294         written = rtlx_write(RTLX_CHANNEL_SYSIO, &ret, sizeof(ret));
 295         set_fs(old_fs);
 296         if (written < sizeof(ret))
 297                 printk("KSPD: sp_work_handle_request failed to send to SP\n");
 298 }
 299
 300 static void sp_cleanup(void)
 301 {
 302         struct files_struct *files = current->files;
 303         int i, j;
 304         struct fdtable *fdt;
 305
 306         j = 0;
 307
 308         /*
 309          * It is safe to dereference the fd table without RCU or
 310          * ->file_lock
 311          */
 312         fdt = files_fdtable(files);
 313         for (;;) {
 314                 unsigned long set;
 315                 i = j * __NFDBITS;
 316                 if (i >= fdt->max_fds)
 317                         break;
 318                 set = fdt->open_fds->fds_bits[j++];
 319                 while (set) {
 320                         if (set & 1) {
 321                                 struct file * file = xchg(&fdt->fd[i], NULL);
 322                                 if (file)
 323                                         filp_close(file, files);
 324                         }
 325                         i++;
 326                         set >>= 1;
 327                 }
 328         }
 329 }
 330
 331 static int channel_open = 0;
 332
 333 /* the work handler */
 334 static void sp_work(struct work_struct *unused)
 335 {
 336         if (!channel_open) {
 337                 if( rtlx_open(RTLX_CHANNEL_SYSIO, 1) != 0) {
 338                         printk("KSPD: unable to open sp channel\n");
 339                         sp_stopping = 1;
 340                 } else {
 341                         channel_open++;
 342                         printk(KERN_DEBUG "KSPD: SP channel opened\n");
 343                 }
 344         } else {
 345                 /* wait for some data, allow it to sleep */
 346                 rtlx_read_poll(RTLX_CHANNEL_SYSIO, 1);
 347
 348                 /* Check we haven't been woken because we are stopping */
 349                 if (!sp_stopping)
 350                         sp_work_handle_request();
 351         }
 352
 353         if (!sp_stopping)
 354                 queue_work(workqueue, &work);
 355         else
 356                 sp_cleanup();
 357 }
 358
 359 static void startwork(int vpe)
 360 {
 361         sp_stopping = channel_open = 0;
 362
 363         if (workqueue == NULL) {
 364                 if ((workqueue = create_singlethread_workqueue("kspd")) == NULL) {
 365                         printk(KERN_ERR "unable to start kspd\n");
 366                         return;
 367                 }
 368
 369                 INIT_WORK(&work, sp_work);
 370                 queue_work(workqueue, &work);
 371         } else
 372                 queue_work(workqueue, &work);
 373
 374 }
 375
 376 static void stopwork(int vpe)
 377 {
 378         sp_stopping = 1;
 379
 380         printk(KERN_DEBUG "KSPD: SP stopping\n");
 381 }
 382
 383 void kspd_notify(struct kspd_notifications *notify)
 384 {
 385         list_add(&notify->list, &kspd_notifylist);
 386 }
 387
 388 static struct vpe_notifications notify;
 389 static int kspd_module_init(void)
 390 {
 391         INIT_LIST_HEAD(&kspd_notifylist);
 392
 393         notify.start = startwork;
 394         notify.stop = stopwork;
 395         vpe_notify(SP_VPE, &notify);
 396
 397         return 0;
 398 }
 399
 400 static void kspd_module_exit(void)
 401 {
 402
 403 }
 404
 405 module_init(kspd_module_init);
 406 module_exit(kspd_module_exit);
 407
 408 MODULE_DESCRIPTION("MIPS KSPD");
 409 MODULE_AUTHOR("Elizabeth Oldham, MIPS Technologies, Inc.");
 410 MODULE_LICENSE("GPL");