1 /* 2 * Copyright IBM Corp. 2007,2012 3 * 4 * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>, 5 * Peter Oberparleiter <peter.oberparleiter@de.ibm.com> 6 */ 7 8 #define KMSG_COMPONENT "sclp_cmd" 9 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt 10 11 #include <linux/completion.h> 12 #include <linux/init.h> 13 #include <linux/errno.h> 14 #include <linux/err.h> 15 #include <linux/export.h> 16 #include <linux/slab.h> 17 #include <linux/string.h> 18 #include <linux/mm.h> 19 #include <linux/mmzone.h> 20 #include <linux/memory.h> 21 #include <linux/module.h> 22 #include <linux/platform_device.h> 23 #include <asm/ctl_reg.h> 24 #include <asm/chpid.h> 25 #include <asm/setup.h> 26 #include <asm/page.h> 27 #include <asm/sclp.h> 28 29 #include "sclp.h" 30 31 static void sclp_sync_callback(struct sclp_req *req, void *data) 32 { 33 struct completion *completion = data; 34 35 complete(completion); 36 } 37 38 int sclp_sync_request(sclp_cmdw_t cmd, void *sccb) 39 { 40 return sclp_sync_request_timeout(cmd, sccb, 0); 41 } 42 43 int sclp_sync_request_timeout(sclp_cmdw_t cmd, void *sccb, int timeout) 44 { 45 struct completion completion; 46 struct sclp_req *request; 47 int rc; 48 49 request = kzalloc(sizeof(*request), GFP_KERNEL); 50 if (!request) 51 return -ENOMEM; 52 if (timeout) 53 request->queue_timeout = timeout; 54 request->command = cmd; 55 request->sccb = sccb; 56 request->status = SCLP_REQ_FILLED; 57 request->callback = sclp_sync_callback; 58 request->callback_data = &completion; 59 init_completion(&completion); 60 61 /* Perform sclp request. */ 62 rc = sclp_add_request(request); 63 if (rc) 64 goto out; 65 wait_for_completion(&completion); 66 67 /* Check response. */ 68 if (request->status != SCLP_REQ_DONE) { 69 pr_warning("sync request failed (cmd=0x%08x, " 70 "status=0x%02x)\n", cmd, request->status); 71 rc = -EIO; 72 } 73 out: 74 kfree(request); 75 return rc; 76 } 77 78 /* 79 * CPU configuration related functions. 80 */ 81 82 #define SCLP_CMDW_READ_CPU_INFO 0x00010001 83 #define SCLP_CMDW_CONFIGURE_CPU 0x00110001 84 #define SCLP_CMDW_DECONFIGURE_CPU 0x00100001 85 86 struct read_cpu_info_sccb { 87 struct sccb_header header; 88 u16 nr_configured; 89 u16 offset_configured; 90 u16 nr_standby; 91 u16 offset_standby; 92 u8 reserved[4096 - 16]; 93 } __attribute__((packed, aligned(PAGE_SIZE))); 94 95 static void sclp_fill_core_info(struct sclp_core_info *info, 96 struct read_cpu_info_sccb *sccb) 97 { 98 char *page = (char *) sccb; 99 100 memset(info, 0, sizeof(*info)); 101 info->configured = sccb->nr_configured; 102 info->standby = sccb->nr_standby; 103 info->combined = sccb->nr_configured + sccb->nr_standby; 104 memcpy(&info->core, page + sccb->offset_configured, 105 info->combined * sizeof(struct sclp_core_entry)); 106 } 107 108 int sclp_get_core_info(struct sclp_core_info *info) 109 { 110 int rc; 111 struct read_cpu_info_sccb *sccb; 112 113 if (!SCLP_HAS_CPU_INFO) 114 return -EOPNOTSUPP; 115 sccb = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA); 116 if (!sccb) 117 return -ENOMEM; 118 sccb->header.length = sizeof(*sccb); 119 rc = sclp_sync_request_timeout(SCLP_CMDW_READ_CPU_INFO, sccb, 120 SCLP_QUEUE_INTERVAL); 121 if (rc) 122 goto out; 123 if (sccb->header.response_code != 0x0010) { 124 pr_warning("readcpuinfo failed (response=0x%04x)\n", 125 sccb->header.response_code); 126 rc = -EIO; 127 goto out; 128 } 129 sclp_fill_core_info(info, sccb); 130 out: 131 free_page((unsigned long) sccb); 132 return rc; 133 } 134 135 struct cpu_configure_sccb { 136 struct sccb_header header; 137 } __attribute__((packed, aligned(8))); 138 139 static int do_core_configure(sclp_cmdw_t cmd) 140 { 141 struct cpu_configure_sccb *sccb; 142 int rc; 143 144 if (!SCLP_HAS_CPU_RECONFIG) 145 return -EOPNOTSUPP; 146 /* 147 * This is not going to cross a page boundary since we force 148 * kmalloc to have a minimum alignment of 8 bytes on s390. 149 */ 150 sccb = kzalloc(sizeof(*sccb), GFP_KERNEL | GFP_DMA); 151 if (!sccb) 152 return -ENOMEM; 153 sccb->header.length = sizeof(*sccb); 154 rc = sclp_sync_request_timeout(cmd, sccb, SCLP_QUEUE_INTERVAL); 155 if (rc) 156 goto out; 157 switch (sccb->header.response_code) { 158 case 0x0020: 159 case 0x0120: 160 break; 161 default: 162 pr_warning("configure cpu failed (cmd=0x%08x, " 163 "response=0x%04x)\n", cmd, 164 sccb->header.response_code); 165 rc = -EIO; 166 break; 167 } 168 out: 169 kfree(sccb); 170 return rc; 171 } 172 173 int sclp_core_configure(u8 core) 174 { 175 return do_core_configure(SCLP_CMDW_CONFIGURE_CPU | core << 8); 176 } 177 178 int sclp_core_deconfigure(u8 core) 179 { 180 return do_core_configure(SCLP_CMDW_DECONFIGURE_CPU | core << 8); 181 } 182 183 #ifdef CONFIG_MEMORY_HOTPLUG 184 185 static DEFINE_MUTEX(sclp_mem_mutex); 186 static LIST_HEAD(sclp_mem_list); 187 static u8 sclp_max_storage_id; 188 static DECLARE_BITMAP(sclp_storage_ids, 256); 189 static int sclp_mem_state_changed; 190 191 struct memory_increment { 192 struct list_head list; 193 u16 rn; 194 int standby; 195 }; 196 197 struct assign_storage_sccb { 198 struct sccb_header header; 199 u16 rn; 200 } __packed; 201 202 int arch_get_memory_phys_device(unsigned long start_pfn) 203 { 204 if (!sclp.rzm) 205 return 0; 206 return PFN_PHYS(start_pfn) >> ilog2(sclp.rzm); 207 } 208 209 static unsigned long long rn2addr(u16 rn) 210 { 211 return (unsigned long long) (rn - 1) * sclp.rzm; 212 } 213 214 static int do_assign_storage(sclp_cmdw_t cmd, u16 rn) 215 { 216 struct assign_storage_sccb *sccb; 217 int rc; 218 219 sccb = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA); 220 if (!sccb) 221 return -ENOMEM; 222 sccb->header.length = PAGE_SIZE; 223 sccb->rn = rn; 224 rc = sclp_sync_request_timeout(cmd, sccb, SCLP_QUEUE_INTERVAL); 225 if (rc) 226 goto out; 227 switch (sccb->header.response_code) { 228 case 0x0020: 229 case 0x0120: 230 break; 231 default: 232 pr_warning("assign storage failed (cmd=0x%08x, " 233 "response=0x%04x, rn=0x%04x)\n", cmd, 234 sccb->header.response_code, rn); 235 rc = -EIO; 236 break; 237 } 238 out: 239 free_page((unsigned long) sccb); 240 return rc; 241 } 242 243 static int sclp_assign_storage(u16 rn) 244 { 245 unsigned long long start; 246 int rc; 247 248 rc = do_assign_storage(0x000d0001, rn); 249 if (rc) 250 return rc; 251 start = rn2addr(rn); 252 storage_key_init_range(start, start + sclp.rzm); 253 return 0; 254 } 255 256 static int sclp_unassign_storage(u16 rn) 257 { 258 return do_assign_storage(0x000c0001, rn); 259 } 260 261 struct attach_storage_sccb { 262 struct sccb_header header; 263 u16 :16; 264 u16 assigned; 265 u32 :32; 266 u32 entries[0]; 267 } __packed; 268 269 static int sclp_attach_storage(u8 id) 270 { 271 struct attach_storage_sccb *sccb; 272 int rc; 273 int i; 274 275 sccb = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA); 276 if (!sccb) 277 return -ENOMEM; 278 sccb->header.length = PAGE_SIZE; 279 rc = sclp_sync_request_timeout(0x00080001 | id << 8, sccb, 280 SCLP_QUEUE_INTERVAL); 281 if (rc) 282 goto out; 283 switch (sccb->header.response_code) { 284 case 0x0020: 285 set_bit(id, sclp_storage_ids); 286 for (i = 0; i < sccb->assigned; i++) { 287 if (sccb->entries[i]) 288 sclp_unassign_storage(sccb->entries[i] >> 16); 289 } 290 break; 291 default: 292 rc = -EIO; 293 break; 294 } 295 out: 296 free_page((unsigned long) sccb); 297 return rc; 298 } 299 300 static int sclp_mem_change_state(unsigned long start, unsigned long size, 301 int online) 302 { 303 struct memory_increment *incr; 304 unsigned long long istart; 305 int rc = 0; 306 307 list_for_each_entry(incr, &sclp_mem_list, list) { 308 istart = rn2addr(incr->rn); 309 if (start + size - 1 < istart) 310 break; 311 if (start > istart + sclp.rzm - 1) 312 continue; 313 if (online) 314 rc |= sclp_assign_storage(incr->rn); 315 else 316 sclp_unassign_storage(incr->rn); 317 if (rc == 0) 318 incr->standby = online ? 0 : 1; 319 } 320 return rc ? -EIO : 0; 321 } 322 323 static bool contains_standby_increment(unsigned long start, unsigned long end) 324 { 325 struct memory_increment *incr; 326 unsigned long istart; 327 328 list_for_each_entry(incr, &sclp_mem_list, list) { 329 istart = rn2addr(incr->rn); 330 if (end - 1 < istart) 331 continue; 332 if (start > istart + sclp.rzm - 1) 333 continue; 334 if (incr->standby) 335 return true; 336 } 337 return false; 338 } 339 340 static int sclp_mem_notifier(struct notifier_block *nb, 341 unsigned long action, void *data) 342 { 343 unsigned long start, size; 344 struct memory_notify *arg; 345 unsigned char id; 346 int rc = 0; 347 348 arg = data; 349 start = arg->start_pfn << PAGE_SHIFT; 350 size = arg->nr_pages << PAGE_SHIFT; 351 mutex_lock(&sclp_mem_mutex); 352 for_each_clear_bit(id, sclp_storage_ids, sclp_max_storage_id + 1) 353 sclp_attach_storage(id); 354 switch (action) { 355 case MEM_GOING_OFFLINE: 356 /* 357 * We do not allow to set memory blocks offline that contain 358 * standby memory. This is done to simplify the "memory online" 359 * case. 360 */ 361 if (contains_standby_increment(start, start + size)) 362 rc = -EPERM; 363 break; 364 case MEM_ONLINE: 365 case MEM_CANCEL_OFFLINE: 366 break; 367 case MEM_GOING_ONLINE: 368 rc = sclp_mem_change_state(start, size, 1); 369 break; 370 case MEM_CANCEL_ONLINE: 371 sclp_mem_change_state(start, size, 0); 372 break; 373 case MEM_OFFLINE: 374 sclp_mem_change_state(start, size, 0); 375 break; 376 default: 377 rc = -EINVAL; 378 break; 379 } 380 if (!rc) 381 sclp_mem_state_changed = 1; 382 mutex_unlock(&sclp_mem_mutex); 383 return rc ? NOTIFY_BAD : NOTIFY_OK; 384 } 385 386 static struct notifier_block sclp_mem_nb = { 387 .notifier_call = sclp_mem_notifier, 388 }; 389 390 static void __init align_to_block_size(unsigned long long *start, 391 unsigned long long *size) 392 { 393 unsigned long long start_align, size_align, alignment; 394 395 alignment = memory_block_size_bytes(); 396 start_align = roundup(*start, alignment); 397 size_align = rounddown(*start + *size, alignment) - start_align; 398 399 pr_info("Standby memory at 0x%llx (%lluM of %lluM usable)\n", 400 *start, size_align >> 20, *size >> 20); 401 *start = start_align; 402 *size = size_align; 403 } 404 405 static void __init add_memory_merged(u16 rn) 406 { 407 static u16 first_rn, num; 408 unsigned long long start, size; 409 410 if (rn && first_rn && (first_rn + num == rn)) { 411 num++; 412 return; 413 } 414 if (!first_rn) 415 goto skip_add; 416 start = rn2addr(first_rn); 417 size = (unsigned long long) num * sclp.rzm; 418 if (start >= VMEM_MAX_PHYS) 419 goto skip_add; 420 if (start + size > VMEM_MAX_PHYS) 421 size = VMEM_MAX_PHYS - start; 422 if (memory_end_set && (start >= memory_end)) 423 goto skip_add; 424 if (memory_end_set && (start + size > memory_end)) 425 size = memory_end - start; 426 align_to_block_size(&start, &size); 427 if (size) 428 add_memory(0, start, size); 429 skip_add: 430 first_rn = rn; 431 num = 1; 432 } 433 434 static void __init sclp_add_standby_memory(void) 435 { 436 struct memory_increment *incr; 437 438 list_for_each_entry(incr, &sclp_mem_list, list) 439 if (incr->standby) 440 add_memory_merged(incr->rn); 441 add_memory_merged(0); 442 } 443 444 static void __init insert_increment(u16 rn, int standby, int assigned) 445 { 446 struct memory_increment *incr, *new_incr; 447 struct list_head *prev; 448 u16 last_rn; 449 450 new_incr = kzalloc(sizeof(*new_incr), GFP_KERNEL); 451 if (!new_incr) 452 return; 453 new_incr->rn = rn; 454 new_incr->standby = standby; 455 last_rn = 0; 456 prev = &sclp_mem_list; 457 list_for_each_entry(incr, &sclp_mem_list, list) { 458 if (assigned && incr->rn > rn) 459 break; 460 if (!assigned && incr->rn - last_rn > 1) 461 break; 462 last_rn = incr->rn; 463 prev = &incr->list; 464 } 465 if (!assigned) 466 new_incr->rn = last_rn + 1; 467 if (new_incr->rn > sclp.rnmax) { 468 kfree(new_incr); 469 return; 470 } 471 list_add(&new_incr->list, prev); 472 } 473 474 static int sclp_mem_freeze(struct device *dev) 475 { 476 if (!sclp_mem_state_changed) 477 return 0; 478 pr_err("Memory hotplug state changed, suspend refused.\n"); 479 return -EPERM; 480 } 481 482 struct read_storage_sccb { 483 struct sccb_header header; 484 u16 max_id; 485 u16 assigned; 486 u16 standby; 487 u16 :16; 488 u32 entries[0]; 489 } __packed; 490 491 static const struct dev_pm_ops sclp_mem_pm_ops = { 492 .freeze = sclp_mem_freeze, 493 }; 494 495 static struct platform_driver sclp_mem_pdrv = { 496 .driver = { 497 .name = "sclp_mem", 498 .pm = &sclp_mem_pm_ops, 499 }, 500 }; 501 502 static int __init sclp_detect_standby_memory(void) 503 { 504 struct platform_device *sclp_pdev; 505 struct read_storage_sccb *sccb; 506 int i, id, assigned, rc; 507 508 if (OLDMEM_BASE) /* No standby memory in kdump mode */ 509 return 0; 510 if ((sclp.facilities & 0xe00000000000ULL) != 0xe00000000000ULL) 511 return 0; 512 rc = -ENOMEM; 513 sccb = (void *) __get_free_page(GFP_KERNEL | GFP_DMA); 514 if (!sccb) 515 goto out; 516 assigned = 0; 517 for (id = 0; id <= sclp_max_storage_id; id++) { 518 memset(sccb, 0, PAGE_SIZE); 519 sccb->header.length = PAGE_SIZE; 520 rc = sclp_sync_request(0x00040001 | id << 8, sccb); 521 if (rc) 522 goto out; 523 switch (sccb->header.response_code) { 524 case 0x0010: 525 set_bit(id, sclp_storage_ids); 526 for (i = 0; i < sccb->assigned; i++) { 527 if (!sccb->entries[i]) 528 continue; 529 assigned++; 530 insert_increment(sccb->entries[i] >> 16, 0, 1); 531 } 532 break; 533 case 0x0310: 534 break; 535 case 0x0410: 536 for (i = 0; i < sccb->assigned; i++) { 537 if (!sccb->entries[i]) 538 continue; 539 assigned++; 540 insert_increment(sccb->entries[i] >> 16, 1, 1); 541 } 542 break; 543 default: 544 rc = -EIO; 545 break; 546 } 547 if (!rc) 548 sclp_max_storage_id = sccb->max_id; 549 } 550 if (rc || list_empty(&sclp_mem_list)) 551 goto out; 552 for (i = 1; i <= sclp.rnmax - assigned; i++) 553 insert_increment(0, 1, 0); 554 rc = register_memory_notifier(&sclp_mem_nb); 555 if (rc) 556 goto out; 557 rc = platform_driver_register(&sclp_mem_pdrv); 558 if (rc) 559 goto out; 560 sclp_pdev = platform_device_register_simple("sclp_mem", -1, NULL, 0); 561 rc = PTR_ERR_OR_ZERO(sclp_pdev); 562 if (rc) 563 goto out_driver; 564 sclp_add_standby_memory(); 565 goto out; 566 out_driver: 567 platform_driver_unregister(&sclp_mem_pdrv); 568 out: 569 free_page((unsigned long) sccb); 570 return rc; 571 } 572 __initcall(sclp_detect_standby_memory); 573 574 #endif /* CONFIG_MEMORY_HOTPLUG */ 575 576 /* 577 * PCI I/O adapter configuration related functions. 578 */ 579 #define SCLP_CMDW_CONFIGURE_PCI 0x001a0001 580 #define SCLP_CMDW_DECONFIGURE_PCI 0x001b0001 581 582 #define SCLP_RECONFIG_PCI_ATPYE 2 583 584 struct pci_cfg_sccb { 585 struct sccb_header header; 586 u8 atype; /* adapter type */ 587 u8 reserved1; 588 u16 reserved2; 589 u32 aid; /* adapter identifier */ 590 } __packed; 591 592 static int do_pci_configure(sclp_cmdw_t cmd, u32 fid) 593 { 594 struct pci_cfg_sccb *sccb; 595 int rc; 596 597 if (!SCLP_HAS_PCI_RECONFIG) 598 return -EOPNOTSUPP; 599 600 sccb = (struct pci_cfg_sccb *) get_zeroed_page(GFP_KERNEL | GFP_DMA); 601 if (!sccb) 602 return -ENOMEM; 603 604 sccb->header.length = PAGE_SIZE; 605 sccb->atype = SCLP_RECONFIG_PCI_ATPYE; 606 sccb->aid = fid; 607 rc = sclp_sync_request(cmd, sccb); 608 if (rc) 609 goto out; 610 switch (sccb->header.response_code) { 611 case 0x0020: 612 case 0x0120: 613 break; 614 default: 615 pr_warn("configure PCI I/O adapter failed: cmd=0x%08x response=0x%04x\n", 616 cmd, sccb->header.response_code); 617 rc = -EIO; 618 break; 619 } 620 out: 621 free_page((unsigned long) sccb); 622 return rc; 623 } 624 625 int sclp_pci_configure(u32 fid) 626 { 627 return do_pci_configure(SCLP_CMDW_CONFIGURE_PCI, fid); 628 } 629 EXPORT_SYMBOL(sclp_pci_configure); 630 631 int sclp_pci_deconfigure(u32 fid) 632 { 633 return do_pci_configure(SCLP_CMDW_DECONFIGURE_PCI, fid); 634 } 635 EXPORT_SYMBOL(sclp_pci_deconfigure); 636 637 /* 638 * Channel path configuration related functions. 639 */ 640 641 #define SCLP_CMDW_CONFIGURE_CHPATH 0x000f0001 642 #define SCLP_CMDW_DECONFIGURE_CHPATH 0x000e0001 643 #define SCLP_CMDW_READ_CHPATH_INFORMATION 0x00030001 644 645 struct chp_cfg_sccb { 646 struct sccb_header header; 647 u8 ccm; 648 u8 reserved[6]; 649 u8 cssid; 650 } __attribute__((packed)); 651 652 static int do_chp_configure(sclp_cmdw_t cmd) 653 { 654 struct chp_cfg_sccb *sccb; 655 int rc; 656 657 if (!SCLP_HAS_CHP_RECONFIG) 658 return -EOPNOTSUPP; 659 /* Prepare sccb. */ 660 sccb = (struct chp_cfg_sccb *) get_zeroed_page(GFP_KERNEL | GFP_DMA); 661 if (!sccb) 662 return -ENOMEM; 663 sccb->header.length = sizeof(*sccb); 664 rc = sclp_sync_request(cmd, sccb); 665 if (rc) 666 goto out; 667 switch (sccb->header.response_code) { 668 case 0x0020: 669 case 0x0120: 670 case 0x0440: 671 case 0x0450: 672 break; 673 default: 674 pr_warning("configure channel-path failed " 675 "(cmd=0x%08x, response=0x%04x)\n", cmd, 676 sccb->header.response_code); 677 rc = -EIO; 678 break; 679 } 680 out: 681 free_page((unsigned long) sccb); 682 return rc; 683 } 684 685 /** 686 * sclp_chp_configure - perform configure channel-path sclp command 687 * @chpid: channel-path ID 688 * 689 * Perform configure channel-path command sclp command for specified chpid. 690 * Return 0 after command successfully finished, non-zero otherwise. 691 */ 692 int sclp_chp_configure(struct chp_id chpid) 693 { 694 return do_chp_configure(SCLP_CMDW_CONFIGURE_CHPATH | chpid.id << 8); 695 } 696 697 /** 698 * sclp_chp_deconfigure - perform deconfigure channel-path sclp command 699 * @chpid: channel-path ID 700 * 701 * Perform deconfigure channel-path command sclp command for specified chpid 702 * and wait for completion. On success return 0. Return non-zero otherwise. 703 */ 704 int sclp_chp_deconfigure(struct chp_id chpid) 705 { 706 return do_chp_configure(SCLP_CMDW_DECONFIGURE_CHPATH | chpid.id << 8); 707 } 708 709 struct chp_info_sccb { 710 struct sccb_header header; 711 u8 recognized[SCLP_CHP_INFO_MASK_SIZE]; 712 u8 standby[SCLP_CHP_INFO_MASK_SIZE]; 713 u8 configured[SCLP_CHP_INFO_MASK_SIZE]; 714 u8 ccm; 715 u8 reserved[6]; 716 u8 cssid; 717 } __attribute__((packed)); 718 719 /** 720 * sclp_chp_read_info - perform read channel-path information sclp command 721 * @info: resulting channel-path information data 722 * 723 * Perform read channel-path information sclp command and wait for completion. 724 * On success, store channel-path information in @info and return 0. Return 725 * non-zero otherwise. 726 */ 727 int sclp_chp_read_info(struct sclp_chp_info *info) 728 { 729 struct chp_info_sccb *sccb; 730 int rc; 731 732 if (!SCLP_HAS_CHP_INFO) 733 return -EOPNOTSUPP; 734 /* Prepare sccb. */ 735 sccb = (struct chp_info_sccb *) get_zeroed_page(GFP_KERNEL | GFP_DMA); 736 if (!sccb) 737 return -ENOMEM; 738 sccb->header.length = sizeof(*sccb); 739 rc = sclp_sync_request(SCLP_CMDW_READ_CHPATH_INFORMATION, sccb); 740 if (rc) 741 goto out; 742 if (sccb->header.response_code != 0x0010) { 743 pr_warning("read channel-path info failed " 744 "(response=0x%04x)\n", sccb->header.response_code); 745 rc = -EIO; 746 goto out; 747 } 748 memcpy(info->recognized, sccb->recognized, SCLP_CHP_INFO_MASK_SIZE); 749 memcpy(info->standby, sccb->standby, SCLP_CHP_INFO_MASK_SIZE); 750 memcpy(info->configured, sccb->configured, SCLP_CHP_INFO_MASK_SIZE); 751 out: 752 free_page((unsigned long) sccb); 753 return rc; 754 } 755