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
  74 #define MTSP_O_RDONLY           0x0000
  75 #define MTSP_O_WRONLY           0x0001
  76 #define MTSP_O_RDWR             0x0002
  77 #define MTSP_O_NONBLOCK         0x0004
  78 #define MTSP_O_APPEND           0x0008
  79 #define MTSP_O_SHLOCK           0x0010
  80 #define MTSP_O_EXLOCK           0x0020
  81 #define MTSP_O_ASYNC            0x0040
  82 #define MTSP_O_FSYNC            O_SYNC
  83 #define MTSP_O_NOFOLLOW         0x0100
  84 #define MTSP_O_SYNC             0x0080
  85 #define MTSP_O_CREAT            0x0200
  86 #define MTSP_O_TRUNC            0x0400
  87 #define MTSP_O_EXCL             0x0800
  88 #define MTSP_O_BINARY           0x8000
  89
  90 #define SP_VPE 1
  91
  92 struct apsp_table  {
  93         int sp;
  94         int ap;
  95 };
  96
  97 /* we might want to do the mode flags too */
  98 struct apsp_table open_flags_table[] = {
  99         { MTSP_O_RDWR, O_RDWR },
 100         { MTSP_O_WRONLY, O_WRONLY },
 101         { MTSP_O_CREAT, O_CREAT },
 102         { MTSP_O_TRUNC, O_TRUNC },
 103         { MTSP_O_NONBLOCK, O_NONBLOCK },
 104         { MTSP_O_APPEND, O_APPEND },
 105         { MTSP_O_NOFOLLOW, O_NOFOLLOW }
 106 };
 107
 108 struct apsp_table syscall_command_table[] = {
 109         { MTSP_SYSCALL_OPEN, __NR_open },
 110         { MTSP_SYSCALL_CLOSE, __NR_close },
 111         { MTSP_SYSCALL_READ, __NR_read },
 112         { MTSP_SYSCALL_WRITE, __NR_write },
 113         { MTSP_SYSCALL_LSEEK32, __NR_lseek }
 114 };
 115
 116 static int sp_syscall(int num, int arg0, int arg1, int arg2, int arg3)
 117 {
 118         register long int _num  __asm__ ("$2") = num;
 119         register long int _arg0  __asm__ ("$4") = arg0;
 120         register long int _arg1  __asm__ ("$5") = arg1;
 121         register long int _arg2  __asm__ ("$6") = arg2;
 122         register long int _arg3  __asm__ ("$7") = arg3;
 123
 124         mm_segment_t old_fs;
 125
 126         old_fs = get_fs();
 127         set_fs(KERNEL_DS);
 128
 129         __asm__ __volatile__ (
 130         "       syscall                                 \n"
 131         : "=r" (_num), "=r" (_arg3)
 132         : "r" (_num), "r" (_arg0), "r" (_arg1), "r" (_arg2), "r" (_arg3));
 133
 134         set_fs(old_fs);
 135
 136         /* $a3 is error flag */
 137         if (_arg3)
 138                 return -_num;
 139
 140         return _num;
 141 }
 142
 143 static int translate_syscall_command(int cmd)
 144 {
 145         int i;
 146         int ret = -1;
 147
 148         for (i = 0; i < ARRAY_SIZE(syscall_command_table); i++) {
 149                 if ((cmd == syscall_command_table[i].sp))
 150                         return syscall_command_table[i].ap;
 151         }
 152
 153         return ret;
 154 }
 155
 156 static unsigned int translate_open_flags(int flags)
 157 {
 158         int i;
 159         unsigned int ret = 0;
 160
 161         for (i = 0; i < (sizeof(open_flags_table) / sizeof(struct apsp_table));
 162              i++) {
 163                 if( (flags & open_flags_table[i].sp) ) {
 164                         ret |= open_flags_table[i].ap;
 165                 }
 166         }
 167
 168         return ret;
 169 }
 170
 171
 172 static void sp_setfsuidgid( uid_t uid, gid_t gid)
 173 {
 174         current->fsuid = uid;
 175         current->fsgid = gid;
 176
 177         key_fsuid_changed(current);
 178         key_fsgid_changed(current);
 179 }
 180
 181 /*
 182  * Expects a request to be on the sysio channel. Reads it.  Decides whether
 183  * its a linux syscall and runs it, or whatever.  Puts the return code back
 184  * into the request and sends the whole thing back.
 185  */
 186 void sp_work_handle_request(void)
 187 {
 188         struct mtsp_syscall sc;
 189         struct mtsp_syscall_generic generic;
 190         struct mtsp_syscall_ret ret;
 191         struct kspd_notifications *n;
 192         struct timeval tv;
 193         struct timezone tz;
 194         int cmd;
 195
 196         char *vcwd;
 197         mm_segment_t old_fs;
 198         int size;
 199
 200         ret.retval = -1;
 201
 202         if (!rtlx_read(RTLX_CHANNEL_SYSIO, &sc, sizeof(struct mtsp_syscall), 0)) {
 203                 printk(KERN_ERR "Expected request but nothing to read\n");
 204                 return;
 205         }
 206
 207         size = sc.size;
 208
 209         if (size) {
 210                 if (!rtlx_read(RTLX_CHANNEL_SYSIO, &generic, size, 0)) {
 211                         printk(KERN_ERR "Expected request but nothing to read\n");
 212                         return;
 213                 }
 214         }
 215
 216         /* Run the syscall at the priviledge of the user who loaded the
 217            SP program */
 218
 219         if (vpe_getuid(SP_VPE))
 220                 sp_setfsuidgid( vpe_getuid(SP_VPE), vpe_getgid(SP_VPE));
 221
 222         switch (sc.cmd) {
 223         /* needs the flags argument translating from SDE kit to
 224            linux */
 225         case MTSP_SYSCALL_PIPEFREQ:
 226                 ret.retval = cpu_khz * 1000;
 227                 ret.errno = 0;
 228                 break;
 229
 230         case MTSP_SYSCALL_GETTOD:
 231                 memset(&tz, 0, sizeof(tz));
 232                 if ((ret.retval = sp_syscall(__NR_gettimeofday, (int)&tv,
 233                                              (int)&tz, 0,0)) == 0)
 234                 ret.retval = tv.tv_sec;
 235
 236                 ret.errno = errno;
 237                 break;
 238
 239         case MTSP_SYSCALL_EXIT:
 240                 list_for_each_entry(n, &kspd_notifylist, list)
 241                         n->kspd_sp_exit(SP_VPE);
 242                 sp_stopping = 1;
 243
 244                 printk(KERN_DEBUG "KSPD got exit syscall from SP exitcode %d\n",
 245                        generic.arg0);
 246                 break;
 247
 248         case MTSP_SYSCALL_OPEN:
 249                 generic.arg1 = translate_open_flags(generic.arg1);
 250
 251                 vcwd = vpe_getcwd(SP_VPE);
 252
 253                 /* change to the cwd of the process that loaded the SP program */
 254                 old_fs = get_fs();
 255                 set_fs(KERNEL_DS);
 256                 sys_chdir(vcwd);
 257                 set_fs(old_fs);
 258
 259                 sc.cmd = __NR_open;
 260
 261                 /* fall through */
 262
 263         default:
 264                 if ((sc.cmd >= __NR_Linux) &&
 265                     (sc.cmd <= (__NR_Linux +  __NR_Linux_syscalls)) )
 266                         cmd = sc.cmd;
 267                 else
 268                         cmd = translate_syscall_command(sc.cmd);
 269
 270                 if (cmd >= 0) {
 271                         ret.retval = sp_syscall(cmd, generic.arg0, generic.arg1,
 272                                                 generic.arg2, generic.arg3);
 273                         ret.errno = errno;
 274                 } else
 275                         printk(KERN_WARNING
 276                                "KSPD: Unknown SP syscall number %d\n", sc.cmd);
 277                 break;
 278         } /* switch */
 279
 280         if (vpe_getuid(SP_VPE))
 281                 sp_setfsuidgid( 0, 0);
 282
 283         if ((rtlx_write(RTLX_CHANNEL_SYSIO, &ret, sizeof(struct mtsp_syscall_ret), 0))
 284             < sizeof(struct mtsp_syscall_ret))
 285                 printk("KSPD: sp_work_handle_request failed to send to SP\n");
 286 }
 287
 288 static void sp_cleanup(void)
 289 {
 290         struct files_struct *files = current->files;
 291         int i, j;
 292         struct fdtable *fdt;
 293
 294         j = 0;
 295
 296         /*
 297          * It is safe to dereference the fd table without RCU or
 298          * ->file_lock
 299          */
 300         fdt = files_fdtable(files);
 301         for (;;) {
 302                 unsigned long set;
 303                 i = j * __NFDBITS;
 304                 if (i >= fdt->max_fdset || i >= fdt->max_fds)
 305                         break;
 306                 set = fdt->open_fds->fds_bits[j++];
 307                 while (set) {
 308                         if (set & 1) {
 309                                 struct file * file = xchg(&fdt->fd[i], NULL);
 310                                 if (file)
 311                                         filp_close(file, files);
 312                         }
 313                         i++;
 314                         set >>= 1;
 315                 }
 316         }
 317 }
 318
 319 static int channel_open = 0;
 320
 321 /* the work handler */
 322 static void sp_work(struct work_struct *unused)
 323 {
 324         if (!channel_open) {
 325                 if( rtlx_open(RTLX_CHANNEL_SYSIO, 1) != 0) {
 326                         printk("KSPD: unable to open sp channel\n");
 327                         sp_stopping = 1;
 328                 } else {
 329                         channel_open++;
 330                         printk(KERN_DEBUG "KSPD: SP channel opened\n");
 331                 }
 332         } else {
 333                 /* wait for some data, allow it to sleep */
 334                 rtlx_read_poll(RTLX_CHANNEL_SYSIO, 1);
 335
 336                 /* Check we haven't been woken because we are stopping */
 337                 if (!sp_stopping)
 338                         sp_work_handle_request();
 339         }
 340
 341         if (!sp_stopping)
 342                 queue_work(workqueue, &work);
 343         else
 344                 sp_cleanup();
 345 }
 346
 347 static void startwork(int vpe)
 348 {
 349         sp_stopping = channel_open = 0;
 350
 351         if (workqueue == NULL) {
 352                 if ((workqueue = create_singlethread_workqueue("kspd")) == NULL) {
 353                         printk(KERN_ERR "unable to start kspd\n");
 354                         return;
 355                 }
 356
 357                 INIT_WORK(&work, sp_work);
 358                 queue_work(workqueue, &work);
 359         } else
 360                 queue_work(workqueue, &work);
 361
 362 }
 363
 364 static void stopwork(int vpe)
 365 {
 366         sp_stopping = 1;
 367
 368         printk(KERN_DEBUG "KSPD: SP stopping\n");
 369 }
 370
 371 void kspd_notify(struct kspd_notifications *notify)
 372 {
 373         list_add(&notify->list, &kspd_notifylist);
 374 }
 375
 376 static struct vpe_notifications notify;
 377 static int kspd_module_init(void)
 378 {
 379         INIT_LIST_HEAD(&kspd_notifylist);
 380
 381         notify.start = startwork;
 382         notify.stop = stopwork;
 383         vpe_notify(SP_VPE, &notify);
 384
 385         return 0;
 386 }
 387
 388 static void kspd_module_exit(void)
 389 {
 390
 391 }
 392
 393 module_init(kspd_module_init);
 394 module_exit(kspd_module_exit);
 395
 396 MODULE_DESCRIPTION("MIPS KSPD");
 397 MODULE_AUTHOR("Elizabeth Oldham, MIPS Technologies, Inc.");
 398 MODULE_LICENSE("GPL");