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;
  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;
  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 int sp_setfsuidgid(uid_t uid, gid_t gid)
 176 {
 177         struct cred *new;
 178
 179         new = prepare_creds();
 180         if (!new)
 181                 return -ENOMEM;
 182
 183         new->fsuid = uid;
 184         new->fsgid = gid;
 185
 186         commit_creds(new);
 187
 188         return 0;
 189 }
 190
 191 /*
 192  * Expects a request to be on the sysio channel. Reads it.  Decides whether
 193  * its a linux syscall and runs it, or whatever.  Puts the return code back
 194  * into the request and sends the whole thing back.
 195  */
 196 void sp_work_handle_request(void)
 197 {
 198         struct mtsp_syscall sc;
 199         struct mtsp_syscall_generic generic;
 200         struct mtsp_syscall_ret ret;
 201         struct kspd_notifications *n;
 202         unsigned long written;
 203         mm_segment_t old_fs;
 204         struct timeval tv;
 205         struct timezone tz;
 206         int err, cmd;
 207
 208         char *vcwd;
 209         int size;
 210
 211         ret.retval = -1;
 212
 213         old_fs = get_fs();
 214         set_fs(KERNEL_DS);
 215
 216         if (!rtlx_read(RTLX_CHANNEL_SYSIO, &sc, sizeof(struct mtsp_syscall))) {
 217                 set_fs(old_fs);
 218                 printk(KERN_ERR "Expected request but nothing to read\n");
 219                 return;
 220         }
 221
 222         size = sc.size;
 223
 224         if (size) {
 225                 if (!rtlx_read(RTLX_CHANNEL_SYSIO, &generic, size)) {
 226                         set_fs(old_fs);
 227                         printk(KERN_ERR "Expected request but nothing to read\n");
 228                         return;
 229                 }
 230         }
 231
 232         /* Run the syscall at the privilege of the user who loaded the
 233            SP program */
 234
 235         if (vpe_getuid(tclimit)) {
 236                 err = sp_setfsuidgid(vpe_getuid(tclimit), vpe_getgid(tclimit));
 237                 if (!err)
 238                         pr_err("Change of creds failed\n");
 239         }
 240
 241         switch (sc.cmd) {
 242         /* needs the flags argument translating from SDE kit to
 243            linux */
 244         case MTSP_SYSCALL_PIPEFREQ:
 245                 ret.retval = cpu_khz * 1000;
 246                 ret.errno = 0;
 247                 break;
 248
 249         case MTSP_SYSCALL_GETTOD:
 250                 memset(&tz, 0, sizeof(tz));
 251                 if ((ret.retval = sp_syscall(__NR_gettimeofday, (int)&tv,
 252                                              (int)&tz, 0, 0)) == 0)
 253                 ret.retval = tv.tv_sec;
 254                 break;
 255
 256         case MTSP_SYSCALL_EXIT:
 257                 list_for_each_entry(n, &kspd_notifylist, list)
 258                         n->kspd_sp_exit(tclimit);
 259                 sp_stopping = 1;
 260
 261                 printk(KERN_DEBUG "KSPD got exit syscall from SP exitcode %d\n",
 262                        generic.arg0);
 263                 break;
 264
 265         case MTSP_SYSCALL_OPEN:
 266                 generic.arg1 = translate_open_flags(generic.arg1);
 267
 268                 vcwd = vpe_getcwd(tclimit);
 269
 270                 /* change to cwd of the process that loaded the SP program */
 271                 old_fs = get_fs();
 272                 set_fs(KERNEL_DS);
 273                 sys_chdir(vcwd);
 274                 set_fs(old_fs);
 275
 276                 sc.cmd = __NR_open;
 277
 278                 /* fall through */
 279
 280         default:
 281                 if ((sc.cmd >= __NR_Linux) &&
 282                     (sc.cmd <= (__NR_Linux +  __NR_Linux_syscalls)) )
 283                         cmd = sc.cmd;
 284                 else
 285                         cmd = translate_syscall_command(sc.cmd);
 286
 287                 if (cmd >= 0) {
 288                         ret.retval = sp_syscall(cmd, generic.arg0, generic.arg1,
 289                                                 generic.arg2, generic.arg3);
 290                 } else
 291                         printk(KERN_WARNING
 292                                "KSPD: Unknown SP syscall number %d\n", sc.cmd);
 293                 break;
 294         } /* switch */
 295
 296         if (vpe_getuid(tclimit)) {
 297                 err = sp_setfsuidgid(0, 0);
 298                 if (!err)
 299                         pr_err("restoring old creds failed\n");
 300         }
 301
 302         old_fs = get_fs();
 303         set_fs(KERNEL_DS);
 304         written = rtlx_write(RTLX_CHANNEL_SYSIO, &ret, sizeof(ret));
 305         set_fs(old_fs);
 306         if (written < sizeof(ret))
 307                 printk("KSPD: sp_work_handle_request failed to send to SP\n");
 308 }
 309
 310 static void sp_cleanup(void)
 311 {
 312         struct files_struct *files = current->files;
 313         int i, j;
 314         struct fdtable *fdt;
 315
 316         j = 0;
 317
 318         /*
 319          * It is safe to dereference the fd table without RCU or
 320          * ->file_lock
 321          */
 322         fdt = files_fdtable(files);
 323         for (;;) {
 324                 unsigned long set;
 325                 i = j * __NFDBITS;
 326                 if (i >= fdt->max_fds)
 327                         break;
 328                 set = fdt->open_fds->fds_bits[j++];
 329                 while (set) {
 330                         if (set & 1) {
 331                                 struct file * file = xchg(&fdt->fd[i], NULL);
 332                                 if (file)
 333                                         filp_close(file, files);
 334                         }
 335                         i++;
 336                         set >>= 1;
 337                 }
 338         }
 339
 340         /* Put daemon cwd back to root to avoid umount problems */
 341         sys_chdir("/");
 342 }
 343
 344 static int channel_open;
 345
 346 /* the work handler */
 347 static void sp_work(struct work_struct *unused)
 348 {
 349         if (!channel_open) {
 350                 if( rtlx_open(RTLX_CHANNEL_SYSIO, 1) != 0) {
 351                         printk("KSPD: unable to open sp channel\n");
 352                         sp_stopping = 1;
 353                 } else {
 354                         channel_open++;
 355                         printk(KERN_DEBUG "KSPD: SP channel opened\n");
 356                 }
 357         } else {
 358                 /* wait for some data, allow it to sleep */
 359                 rtlx_read_poll(RTLX_CHANNEL_SYSIO, 1);
 360
 361                 /* Check we haven't been woken because we are stopping */
 362                 if (!sp_stopping)
 363                         sp_work_handle_request();
 364         }
 365
 366         if (!sp_stopping)
 367                 queue_work(workqueue, &work);
 368         else
 369                 sp_cleanup();
 370 }
 371
 372 static void startwork(int vpe)
 373 {
 374         sp_stopping = channel_open = 0;
 375
 376         if (workqueue == NULL) {
 377                 if ((workqueue = create_singlethread_workqueue("kspd")) == NULL) {
 378                         printk(KERN_ERR "unable to start kspd\n");
 379                         return;
 380                 }
 381
 382                 INIT_WORK(&work, sp_work);
 383         }
 384
 385         queue_work(workqueue, &work);
 386 }
 387
 388 static void stopwork(int vpe)
 389 {
 390         sp_stopping = 1;
 391
 392         printk(KERN_DEBUG "KSPD: SP stopping\n");
 393 }
 394
 395 void kspd_notify(struct kspd_notifications *notify)
 396 {
 397         list_add(&notify->list, &kspd_notifylist);
 398 }
 399
 400 static struct vpe_notifications notify;
 401 static int kspd_module_init(void)
 402 {
 403         INIT_LIST_HEAD(&kspd_notifylist);
 404
 405         notify.start = startwork;
 406         notify.stop = stopwork;
 407         vpe_notify(tclimit, &notify);
 408
 409         return 0;
 410 }
 411
 412 static void kspd_module_exit(void)
 413 {
 414
 415 }
 416
 417 module_init(kspd_module_init);
 418 module_exit(kspd_module_exit);
 419
 420 MODULE_DESCRIPTION("MIPS KSPD");
 421 MODULE_AUTHOR("Elizabeth Oldham, MIPS Technologies, Inc.");
 422 MODULE_LICENSE("GPL");