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/sched.h>
  21 #include <linux/unistd.h>
  22 #include <linux/file.h>
  23 #include <linux/fdtable.h>
  24 #include <linux/fs.h>
  25 #include <linux/syscalls.h>
  26 #include <linux/workqueue.h>
  27 #include <linux/errno.h>
  28 #include <linux/list.h>
  29
  30 #include <asm/vpe.h>
  31 #include <asm/rtlx.h>
  32 #include <asm/kspd.h>
  33
  34 static struct workqueue_struct *workqueue = NULL;
  35 static struct work_struct work;
  36
  37 extern unsigned long cpu_khz;
  38
  39 struct mtsp_syscall {
  40         int cmd;
  41         unsigned char abi;
  42         unsigned char size;
  43 };
  44
  45 struct mtsp_syscall_ret {
  46         int retval;
  47         int errno;
  48 };
  49
  50 struct mtsp_syscall_generic {
  51         int arg0;
  52         int arg1;
  53         int arg2;
  54         int arg3;
  55         int arg4;
  56         int arg5;
  57         int arg6;
  58 };
  59
  60 static struct list_head kspd_notifylist;
  61 static int sp_stopping = 0;
  62
  63 /* these should match with those in the SDE kit */
  64 #define MTSP_SYSCALL_BASE       0
  65 #define MTSP_SYSCALL_EXIT       (MTSP_SYSCALL_BASE + 0)
  66 #define MTSP_SYSCALL_OPEN       (MTSP_SYSCALL_BASE + 1)
  67 #define MTSP_SYSCALL_READ       (MTSP_SYSCALL_BASE + 2)
  68 #define MTSP_SYSCALL_WRITE      (MTSP_SYSCALL_BASE + 3)
  69 #define MTSP_SYSCALL_CLOSE      (MTSP_SYSCALL_BASE + 4)
  70 #define MTSP_SYSCALL_LSEEK32    (MTSP_SYSCALL_BASE + 5)
  71 #define MTSP_SYSCALL_ISATTY     (MTSP_SYSCALL_BASE + 6)
  72 #define MTSP_SYSCALL_GETTIME    (MTSP_SYSCALL_BASE + 7)
  73 #define MTSP_SYSCALL_PIPEFREQ   (MTSP_SYSCALL_BASE + 8)
  74 #define MTSP_SYSCALL_GETTOD     (MTSP_SYSCALL_BASE + 9)
  75 #define MTSP_SYSCALL_IOCTL     (MTSP_SYSCALL_BASE + 10)
  76
  77 #define MTSP_O_RDONLY           0x0000
  78 #define MTSP_O_WRONLY           0x0001
  79 #define MTSP_O_RDWR             0x0002
  80 #define MTSP_O_NONBLOCK         0x0004
  81 #define MTSP_O_APPEND           0x0008
  82 #define MTSP_O_SHLOCK           0x0010
  83 #define MTSP_O_EXLOCK           0x0020
  84 #define MTSP_O_ASYNC            0x0040
  85 #define MTSP_O_FSYNC            O_SYNC
  86 #define MTSP_O_NOFOLLOW         0x0100
  87 #define MTSP_O_SYNC             0x0080
  88 #define MTSP_O_CREAT            0x0200
  89 #define MTSP_O_TRUNC            0x0400
  90 #define MTSP_O_EXCL             0x0800
  91 #define MTSP_O_BINARY           0x8000
  92
  93 extern int tclimit;
  94
  95 struct apsp_table  {
  96         int sp;
  97         int ap;
  98 };
  99
 100 /* we might want to do the mode flags too */
 101 struct apsp_table open_flags_table[] = {
 102         { MTSP_O_RDWR, O_RDWR },
 103         { MTSP_O_WRONLY, O_WRONLY },
 104         { MTSP_O_CREAT, O_CREAT },
 105         { MTSP_O_TRUNC, O_TRUNC },
 106         { MTSP_O_NONBLOCK, O_NONBLOCK },
 107         { MTSP_O_APPEND, O_APPEND },
 108         { MTSP_O_NOFOLLOW, O_NOFOLLOW }
 109 };
 110
 111 struct apsp_table syscall_command_table[] = {
 112         { MTSP_SYSCALL_OPEN, __NR_open },
 113         { MTSP_SYSCALL_CLOSE, __NR_close },
 114         { MTSP_SYSCALL_READ, __NR_read },
 115         { MTSP_SYSCALL_WRITE, __NR_write },
 116         { MTSP_SYSCALL_LSEEK32, __NR_lseek },
 117         { MTSP_SYSCALL_IOCTL, __NR_ioctl }
 118 };
 119
 120 static int sp_syscall(int num, int arg0, int arg1, int arg2, int arg3)
 121 {
 122         register long int _num  __asm__("$2") = num;
 123         register long int _arg0  __asm__("$4") = arg0;
 124         register long int _arg1  __asm__("$5") = arg1;
 125         register long int _arg2  __asm__("$6") = arg2;
 126         register long int _arg3  __asm__("$7") = arg3;
 127
 128         mm_segment_t old_fs;
 129
 130         old_fs = get_fs();
 131         set_fs(KERNEL_DS);
 132
 133         __asm__ __volatile__ (
 134         "       syscall                                 \n"
 135         : "=r" (_num), "=r" (_arg3)
 136         : "r" (_num), "r" (_arg0), "r" (_arg1), "r" (_arg2), "r" (_arg3));
 137
 138         set_fs(old_fs);
 139
 140         /* $a3 is error flag */
 141         if (_arg3)
 142                 return -_num;
 143
 144         return _num;
 145 }
 146
 147 static int translate_syscall_command(int cmd)
 148 {
 149         int i;
 150         int ret = -1;
 151
 152         for (i = 0; i < ARRAY_SIZE(syscall_command_table); i++) {
 153                 if ((cmd == syscall_command_table[i].sp))
 154                         return syscall_command_table[i].ap;
 155         }
 156
 157         return ret;
 158 }
 159
 160 static unsigned int translate_open_flags(int flags)
 161 {
 162         int i;
 163         unsigned int ret = 0;
 164
 165         for (i = 0; i < ARRAY_SIZE(open_flags_table); i++) {
 166                 if( (flags & open_flags_table[i].sp) ) {
 167                         ret |= open_flags_table[i].ap;
 168                 }
 169         }
 170
 171         return ret;
 172 }
 173
 174
 175 static void sp_setfsuidgid( uid_t uid, gid_t gid)
 176 {
 177         current->fsuid = uid;
 178         current->fsgid = gid;
 179
 180         key_fsuid_changed(current);
 181         key_fsgid_changed(current);
 182 }
 183
 184 /*
 185  * Expects a request to be on the sysio channel. Reads it.  Decides whether
 186  * its a linux syscall and runs it, or whatever.  Puts the return code back
 187  * into the request and sends the whole thing back.
 188  */
 189 void sp_work_handle_request(void)
 190 {
 191         struct mtsp_syscall sc;
 192         struct mtsp_syscall_generic generic;
 193         struct mtsp_syscall_ret ret;
 194         struct kspd_notifications *n;
 195         unsigned long written;
 196         mm_segment_t old_fs;
 197         struct timeval tv;
 198         struct timezone tz;
 199         int cmd;
 200
 201         char *vcwd;
 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 privilege of the user who loaded the
 226            SP program */
 227
 228         if (vpe_getuid(tclimit))
 229                 sp_setfsuidgid(vpe_getuid(tclimit), vpe_getgid(tclimit));
 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                 break;
 245
 246         case MTSP_SYSCALL_EXIT:
 247                 list_for_each_entry(n, &kspd_notifylist, list)
 248                         n->kspd_sp_exit(tclimit);
 249                 sp_stopping = 1;
 250
 251                 printk(KERN_DEBUG "KSPD got exit syscall from SP exitcode %d\n",
 252                        generic.arg0);
 253                 break;
 254
 255         case MTSP_SYSCALL_OPEN:
 256                 generic.arg1 = translate_open_flags(generic.arg1);
 257
 258                 vcwd = vpe_getcwd(tclimit);
 259
 260                 /* change to cwd of the process that loaded the SP program */
 261                 old_fs = get_fs();
 262                 set_fs(KERNEL_DS);
 263                 sys_chdir(vcwd);
 264                 set_fs(old_fs);
 265
 266                 sc.cmd = __NR_open;
 267
 268                 /* fall through */
 269
 270         default:
 271                 if ((sc.cmd >= __NR_Linux) &&
 272                     (sc.cmd <= (__NR_Linux +  __NR_Linux_syscalls)) )
 273                         cmd = sc.cmd;
 274                 else
 275                         cmd = translate_syscall_command(sc.cmd);
 276
 277                 if (cmd >= 0) {
 278                         ret.retval = sp_syscall(cmd, generic.arg0, generic.arg1,
 279                                                 generic.arg2, generic.arg3);
 280                 } else
 281                         printk(KERN_WARNING
 282                                "KSPD: Unknown SP syscall number %d\n", sc.cmd);
 283                 break;
 284         } /* switch */
 285
 286         if (vpe_getuid(tclimit))
 287                 sp_setfsuidgid( 0, 0);
 288
 289         old_fs = get_fs();
 290         set_fs(KERNEL_DS);
 291         written = rtlx_write(RTLX_CHANNEL_SYSIO, &ret, sizeof(ret));
 292         set_fs(old_fs);
 293         if (written < sizeof(ret))
 294                 printk("KSPD: sp_work_handle_request failed to send to SP\n");
 295 }
 296
 297 static void sp_cleanup(void)
 298 {
 299         struct files_struct *files = current->files;
 300         int i, j;
 301         struct fdtable *fdt;
 302
 303         j = 0;
 304
 305         /*
 306          * It is safe to dereference the fd table without RCU or
 307          * ->file_lock
 308          */
 309         fdt = files_fdtable(files);
 310         for (;;) {
 311                 unsigned long set;
 312                 i = j * __NFDBITS;
 313                 if (i >= fdt->max_fds)
 314                         break;
 315                 set = fdt->open_fds->fds_bits[j++];
 316                 while (set) {
 317                         if (set & 1) {
 318                                 struct file * file = xchg(&fdt->fd[i], NULL);
 319                                 if (file)
 320                                         filp_close(file, files);
 321                         }
 322                         i++;
 323                         set >>= 1;
 324                 }
 325         }
 326
 327         /* Put daemon cwd back to root to avoid umount problems */
 328         sys_chdir("/");
 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         }
 371
 372         queue_work(workqueue, &work);
 373 }
 374
 375 static void stopwork(int vpe)
 376 {
 377         sp_stopping = 1;
 378
 379         printk(KERN_DEBUG "KSPD: SP stopping\n");
 380 }
 381
 382 void kspd_notify(struct kspd_notifications *notify)
 383 {
 384         list_add(&notify->list, &kspd_notifylist);
 385 }
 386
 387 static struct vpe_notifications notify;
 388 static int kspd_module_init(void)
 389 {
 390         INIT_LIST_HEAD(&kspd_notifylist);
 391
 392         notify.start = startwork;
 393         notify.stop = stopwork;
 394         vpe_notify(tclimit, &notify);
 395
 396         return 0;
 397 }
 398
 399 static void kspd_module_exit(void)
 400 {
 401
 402 }
 403
 404 module_init(kspd_module_init);
 405 module_exit(kspd_module_exit);
 406
 407 MODULE_DESCRIPTION("MIPS KSPD");
 408 MODULE_AUTHOR("Elizabeth Oldham, MIPS Technologies, Inc.");
 409 MODULE_LICENSE("GPL");