arch/s390/mm/cmm.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  Collaborative memory management interface.
   4  *
   5  *    Copyright IBM Corp 2003, 2010
   6  *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
   7  *
   8  */
   9
  10 #include <linux/errno.h>
  11 #include <linux/fs.h>
  12 #include <linux/init.h>
  13 #include <linux/module.h>
  14 #include <linux/moduleparam.h>
  15 #include <linux/gfp.h>
  16 #include <linux/sched.h>
  17 #include <linux/sysctl.h>
  18 #include <linux/ctype.h>
  19 #include <linux/swap.h>
  20 #include <linux/kthread.h>
  21 #include <linux/oom.h>
  22 #include <linux/suspend.h>
  23 #include <linux/uaccess.h>
  24
  25 #include <asm/pgalloc.h>
  26 #include <asm/diag.h>
  27
  28 #ifdef CONFIG_CMM_IUCV
  29 static char *cmm_default_sender = "VMRMSVM";
  30 #endif
  31 static char *sender;
  32 module_param(sender, charp, 0400);
  33 MODULE_PARM_DESC(sender,
  34                  "Guest name that may send SMSG messages (default VMRMSVM)");
  35
  36 #include "../../../drivers/s390/net/smsgiucv.h"
  37
  38 #define CMM_NR_PAGES ((PAGE_SIZE / sizeof(unsigned long)) - 2)
  39
  40 struct cmm_page_array {
  41         struct cmm_page_array *next;
  42         unsigned long index;
  43         unsigned long pages[CMM_NR_PAGES];
  44 };
  45
  46 static long cmm_pages;
  47 static long cmm_timed_pages;
  48 static volatile long cmm_pages_target;
  49 static volatile long cmm_timed_pages_target;
  50 static long cmm_timeout_pages;
  51 static long cmm_timeout_seconds;
  52 static int cmm_suspended;
  53
  54 static struct cmm_page_array *cmm_page_list;
  55 static struct cmm_page_array *cmm_timed_page_list;
  56 static DEFINE_SPINLOCK(cmm_lock);
  57
  58 static struct task_struct *cmm_thread_ptr;
  59 static DECLARE_WAIT_QUEUE_HEAD(cmm_thread_wait);
  60
  61 static void cmm_timer_fn(struct timer_list *);
  62 static void cmm_set_timer(void);
  63 static DEFINE_TIMER(cmm_timer, cmm_timer_fn);
  64
  65 static long cmm_alloc_pages(long nr, long *counter,
  66                             struct cmm_page_array **list)
  67 {
  68         struct cmm_page_array *pa, *npa;
  69         unsigned long addr;
  70
  71         while (nr) {
  72                 addr = __get_free_page(GFP_NOIO);
  73                 if (!addr)
  74                         break;
  75                 spin_lock(&cmm_lock);
  76                 pa = *list;
  77                 if (!pa || pa->index >= CMM_NR_PAGES) {
  78                         /* Need a new page for the page list. */
  79                         spin_unlock(&cmm_lock);
  80                         npa = (struct cmm_page_array *)
  81                                 __get_free_page(GFP_NOIO);
  82                         if (!npa) {
  83                                 free_page(addr);
  84                                 break;
  85                         }
  86                         spin_lock(&cmm_lock);
  87                         pa = *list;
  88                         if (!pa || pa->index >= CMM_NR_PAGES) {
  89                                 npa->next = pa;
  90                                 npa->index = 0;
  91                                 pa = npa;
  92                                 *list = pa;
  93                         } else
  94                                 free_page((unsigned long) npa);
  95                 }
  96                 diag10_range(addr >> PAGE_SHIFT, 1);
  97                 pa->pages[pa->index++] = addr;
  98                 (*counter)++;
  99                 spin_unlock(&cmm_lock);
 100                 nr--;
 101         }
 102         return nr;
 103 }
 104
 105 static long cmm_free_pages(long nr, long *counter, struct cmm_page_array **list)
 106 {
 107         struct cmm_page_array *pa;
 108         unsigned long addr;
 109
 110         spin_lock(&cmm_lock);
 111         pa = *list;
 112         while (nr) {
 113                 if (!pa || pa->index <= 0)
 114                         break;
 115                 addr = pa->pages[--pa->index];
 116                 if (pa->index == 0) {
 117                         pa = pa->next;
 118                         free_page((unsigned long) *list);
 119                         *list = pa;
 120                 }
 121                 free_page(addr);
 122                 (*counter)--;
 123                 nr--;
 124         }
 125         spin_unlock(&cmm_lock);
 126         return nr;
 127 }
 128
 129 static int cmm_oom_notify(struct notifier_block *self,
 130                           unsigned long dummy, void *parm)
 131 {
 132         unsigned long *freed = parm;
 133         long nr = 256;
 134
 135         nr = cmm_free_pages(nr, &cmm_timed_pages, &cmm_timed_page_list);
 136         if (nr > 0)
 137                 nr = cmm_free_pages(nr, &cmm_pages, &cmm_page_list);
 138         cmm_pages_target = cmm_pages;
 139         cmm_timed_pages_target = cmm_timed_pages;
 140         *freed += 256 - nr;
 141         return NOTIFY_OK;
 142 }
 143
 144 static struct notifier_block cmm_oom_nb = {
 145         .notifier_call = cmm_oom_notify,
 146 };
 147
 148 static int cmm_thread(void *dummy)
 149 {
 150         int rc;
 151
 152         while (1) {
 153                 rc = wait_event_interruptible(cmm_thread_wait,
 154                         (!cmm_suspended && (cmm_pages != cmm_pages_target ||
 155                          cmm_timed_pages != cmm_timed_pages_target)) ||
 156                          kthread_should_stop());
 157                 if (kthread_should_stop() || rc == -ERESTARTSYS) {
 158                         cmm_pages_target = cmm_pages;
 159                         cmm_timed_pages_target = cmm_timed_pages;
 160                         break;
 161                 }
 162                 if (cmm_pages_target > cmm_pages) {
 163                         if (cmm_alloc_pages(1, &cmm_pages, &cmm_page_list))
 164                                 cmm_pages_target = cmm_pages;
 165                 } else if (cmm_pages_target < cmm_pages) {
 166                         cmm_free_pages(1, &cmm_pages, &cmm_page_list);
 167                 }
 168                 if (cmm_timed_pages_target > cmm_timed_pages) {
 169                         if (cmm_alloc_pages(1, &cmm_timed_pages,
 170                                            &cmm_timed_page_list))
 171                                 cmm_timed_pages_target = cmm_timed_pages;
 172                 } else if (cmm_timed_pages_target < cmm_timed_pages) {
 173                         cmm_free_pages(1, &cmm_timed_pages,
 174                                        &cmm_timed_page_list);
 175                 }
 176                 if (cmm_timed_pages > 0 && !timer_pending(&cmm_timer))
 177                         cmm_set_timer();
 178         }
 179         return 0;
 180 }
 181
 182 static void cmm_kick_thread(void)
 183 {
 184         wake_up(&cmm_thread_wait);
 185 }
 186
 187 static void cmm_set_timer(void)
 188 {
 189         if (cmm_timed_pages_target <= 0 || cmm_timeout_seconds <= 0) {
 190                 if (timer_pending(&cmm_timer))
 191                         del_timer(&cmm_timer);
 192                 return;
 193         }
 194         if (timer_pending(&cmm_timer)) {
 195                 if (mod_timer(&cmm_timer, jiffies + cmm_timeout_seconds*HZ))
 196                         return;
 197         }
 198         cmm_timer.expires = jiffies + cmm_timeout_seconds*HZ;
 199         add_timer(&cmm_timer);
 200 }
 201
 202 static void cmm_timer_fn(struct timer_list *unused)
 203 {
 204         long nr;
 205
 206         nr = cmm_timed_pages_target - cmm_timeout_pages;
 207         if (nr < 0)
 208                 cmm_timed_pages_target = 0;
 209         else
 210                 cmm_timed_pages_target = nr;
 211         cmm_kick_thread();
 212         cmm_set_timer();
 213 }
 214
 215 static void cmm_set_pages(long nr)
 216 {
 217         cmm_pages_target = nr;
 218         cmm_kick_thread();
 219 }
 220
 221 static long cmm_get_pages(void)
 222 {
 223         return cmm_pages;
 224 }
 225
 226 static void cmm_add_timed_pages(long nr)
 227 {
 228         cmm_timed_pages_target += nr;
 229         cmm_kick_thread();
 230 }
 231
 232 static long cmm_get_timed_pages(void)
 233 {
 234         return cmm_timed_pages;
 235 }
 236
 237 static void cmm_set_timeout(long nr, long seconds)
 238 {
 239         cmm_timeout_pages = nr;
 240         cmm_timeout_seconds = seconds;
 241         cmm_set_timer();
 242 }
 243
 244 static int cmm_skip_blanks(char *cp, char **endp)
 245 {
 246         char *str;
 247
 248         for (str = cp; *str == ' ' || *str == '\t'; str++)
 249                 ;
 250         *endp = str;
 251         return str != cp;
 252 }
 253
 254 static struct ctl_table cmm_table[];
 255
 256 static int cmm_pages_handler(struct ctl_table *ctl, int write,
 257                              void __user *buffer, size_t *lenp, loff_t *ppos)
 258 {
 259         char buf[16], *p;
 260         unsigned int len;
 261         long nr;
 262
 263         if (!*lenp || (*ppos && !write)) {
 264                 *lenp = 0;
 265                 return 0;
 266         }
 267
 268         if (write) {
 269                 len = *lenp;
 270                 if (copy_from_user(buf, buffer,
 271                                    len > sizeof(buf) ? sizeof(buf) : len))
 272                         return -EFAULT;
 273                 buf[sizeof(buf) - 1] = '\0';
 274                 cmm_skip_blanks(buf, &p);
 275                 nr = simple_strtoul(p, &p, 0);
 276                 if (ctl == &cmm_table[0])
 277                         cmm_set_pages(nr);
 278                 else
 279                         cmm_add_timed_pages(nr);
 280         } else {
 281                 if (ctl == &cmm_table[0])
 282                         nr = cmm_get_pages();
 283                 else
 284                         nr = cmm_get_timed_pages();
 285                 len = sprintf(buf, "%ld\n", nr);
 286                 if (len > *lenp)
 287                         len = *lenp;
 288                 if (copy_to_user(buffer, buf, len))
 289                         return -EFAULT;
 290         }
 291         *lenp = len;
 292         *ppos += len;
 293         return 0;
 294 }
 295
 296 static int cmm_timeout_handler(struct ctl_table *ctl, int write,
 297                                void __user *buffer, size_t *lenp, loff_t *ppos)
 298 {
 299         char buf[64], *p;
 300         long nr, seconds;
 301         unsigned int len;
 302
 303         if (!*lenp || (*ppos && !write)) {
 304                 *lenp = 0;
 305                 return 0;
 306         }
 307
 308         if (write) {
 309                 len = *lenp;
 310                 if (copy_from_user(buf, buffer,
 311                                    len > sizeof(buf) ? sizeof(buf) : len))
 312                         return -EFAULT;
 313                 buf[sizeof(buf) - 1] = '\0';
 314                 cmm_skip_blanks(buf, &p);
 315                 nr = simple_strtoul(p, &p, 0);
 316                 cmm_skip_blanks(p, &p);
 317                 seconds = simple_strtoul(p, &p, 0);
 318                 cmm_set_timeout(nr, seconds);
 319         } else {
 320                 len = sprintf(buf, "%ld %ld\n",
 321                               cmm_timeout_pages, cmm_timeout_seconds);
 322                 if (len > *lenp)
 323                         len = *lenp;
 324                 if (copy_to_user(buffer, buf, len))
 325                         return -EFAULT;
 326         }
 327         *lenp = len;
 328         *ppos += len;
 329         return 0;
 330 }
 331
 332 static struct ctl_table cmm_table[] = {
 333         {
 334                 .procname       = "cmm_pages",
 335                 .mode           = 0644,
 336                 .proc_handler   = cmm_pages_handler,
 337         },
 338         {
 339                 .procname       = "cmm_timed_pages",
 340                 .mode           = 0644,
 341                 .proc_handler   = cmm_pages_handler,
 342         },
 343         {
 344                 .procname       = "cmm_timeout",
 345                 .mode           = 0644,
 346                 .proc_handler   = cmm_timeout_handler,
 347         },
 348         { }
 349 };
 350
 351 static struct ctl_table cmm_dir_table[] = {
 352         {
 353                 .procname       = "vm",
 354                 .maxlen         = 0,
 355                 .mode           = 0555,
 356                 .child          = cmm_table,
 357         },
 358         { }
 359 };
 360
 361 #ifdef CONFIG_CMM_IUCV
 362 #define SMSG_PREFIX "CMM"
 363 static void cmm_smsg_target(const char *from, char *msg)
 364 {
 365         long nr, seconds;
 366
 367         if (strlen(sender) > 0 && strcmp(from, sender) != 0)
 368                 return;
 369         if (!cmm_skip_blanks(msg + strlen(SMSG_PREFIX), &msg))
 370                 return;
 371         if (strncmp(msg, "SHRINK", 6) == 0) {
 372                 if (!cmm_skip_blanks(msg + 6, &msg))
 373                         return;
 374                 nr = simple_strtoul(msg, &msg, 0);
 375                 cmm_skip_blanks(msg, &msg);
 376                 if (*msg == '\0')
 377                         cmm_set_pages(nr);
 378         } else if (strncmp(msg, "RELEASE", 7) == 0) {
 379                 if (!cmm_skip_blanks(msg + 7, &msg))
 380                         return;
 381                 nr = simple_strtoul(msg, &msg, 0);
 382                 cmm_skip_blanks(msg, &msg);
 383                 if (*msg == '\0')
 384                         cmm_add_timed_pages(nr);
 385         } else if (strncmp(msg, "REUSE", 5) == 0) {
 386                 if (!cmm_skip_blanks(msg + 5, &msg))
 387                         return;
 388                 nr = simple_strtoul(msg, &msg, 0);
 389                 if (!cmm_skip_blanks(msg, &msg))
 390                         return;
 391                 seconds = simple_strtoul(msg, &msg, 0);
 392                 cmm_skip_blanks(msg, &msg);
 393                 if (*msg == '\0')
 394                         cmm_set_timeout(nr, seconds);
 395         }
 396 }
 397 #endif
 398
 399 static struct ctl_table_header *cmm_sysctl_header;
 400
 401 static int cmm_suspend(void)
 402 {
 403         cmm_suspended = 1;
 404         cmm_free_pages(cmm_pages, &cmm_pages, &cmm_page_list);
 405         cmm_free_pages(cmm_timed_pages, &cmm_timed_pages, &cmm_timed_page_list);
 406         return 0;
 407 }
 408
 409 static int cmm_resume(void)
 410 {
 411         cmm_suspended = 0;
 412         cmm_kick_thread();
 413         return 0;
 414 }
 415
 416 static int cmm_power_event(struct notifier_block *this,
 417                            unsigned long event, void *ptr)
 418 {
 419         switch (event) {
 420         case PM_POST_HIBERNATION:
 421                 return cmm_resume();
 422         case PM_HIBERNATION_PREPARE:
 423                 return cmm_suspend();
 424         default:
 425                 return NOTIFY_DONE;
 426         }
 427 }
 428
 429 static struct notifier_block cmm_power_notifier = {
 430         .notifier_call = cmm_power_event,
 431 };
 432
 433 static int __init cmm_init(void)
 434 {
 435         int rc = -ENOMEM;
 436
 437         cmm_sysctl_header = register_sysctl_table(cmm_dir_table);
 438         if (!cmm_sysctl_header)
 439                 goto out_sysctl;
 440 #ifdef CONFIG_CMM_IUCV
 441         /* convert sender to uppercase characters */
 442         if (sender) {
 443                 int len = strlen(sender);
 444                 while (len--)
 445                         sender[len] = toupper(sender[len]);
 446         } else {
 447                 sender = cmm_default_sender;
 448         }
 449
 450         rc = smsg_register_callback(SMSG_PREFIX, cmm_smsg_target);
 451         if (rc < 0)
 452                 goto out_smsg;
 453 #endif
 454         rc = register_oom_notifier(&cmm_oom_nb);
 455         if (rc < 0)
 456                 goto out_oom_notify;
 457         rc = register_pm_notifier(&cmm_power_notifier);
 458         if (rc)
 459                 goto out_pm;
 460         cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread");
 461         if (!IS_ERR(cmm_thread_ptr))
 462                 return 0;
 463
 464         rc = PTR_ERR(cmm_thread_ptr);
 465         unregister_pm_notifier(&cmm_power_notifier);
 466 out_pm:
 467         unregister_oom_notifier(&cmm_oom_nb);
 468 out_oom_notify:
 469 #ifdef CONFIG_CMM_IUCV
 470         smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
 471 out_smsg:
 472 #endif
 473         unregister_sysctl_table(cmm_sysctl_header);
 474 out_sysctl:
 475         del_timer_sync(&cmm_timer);
 476         return rc;
 477 }
 478 module_init(cmm_init);
 479
 480 static void __exit cmm_exit(void)
 481 {
 482         unregister_sysctl_table(cmm_sysctl_header);
 483 #ifdef CONFIG_CMM_IUCV
 484         smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
 485 #endif
 486         unregister_pm_notifier(&cmm_power_notifier);
 487         unregister_oom_notifier(&cmm_oom_nb);
 488         kthread_stop(cmm_thread_ptr);
 489         del_timer_sync(&cmm_timer);
 490         cmm_free_pages(cmm_pages, &cmm_pages, &cmm_page_list);
 491         cmm_free_pages(cmm_timed_pages, &cmm_timed_pages, &cmm_timed_page_list);
 492 }
 493 module_exit(cmm_exit);
 494
 495 MODULE_LICENSE("GPL");