arch/x86/kernel/cpu/cpufreq/pcc-cpufreq.c

   1 /*
   2  *  pcc-cpufreq.c - Processor Clocking Control firmware cpufreq interface
   3  *
   4  *  Copyright (C) 2009 Red Hat, Matthew Garrett <mjg@redhat.com>
   5  *  Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
   6  *      Nagananda Chumbalkar <nagananda.chumbalkar@hp.com>
   7  *
   8  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License as published by
  12  *  the Free Software Foundation; version 2 of the License.
  13  *
  14  *  This program is distributed in the hope that it will be useful, but
  15  *  WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or NON
  17  *  INFRINGEMENT. See the GNU General Public License for more details.
  18  *
  19  *  You should have received a copy of the GNU General Public License along
  20  *  with this program; if not, write to the Free Software Foundation, Inc.,
  21  *  675 Mass Ave, Cambridge, MA 02139, USA.
  22  *
  23  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  24  */
  25
  26 #include <linux/kernel.h>
  27 #include <linux/module.h>
  28 #include <linux/init.h>
  29 #include <linux/smp.h>
  30 #include <linux/sched.h>
  31 #include <linux/cpufreq.h>
  32 #include <linux/compiler.h>
  33 #include <linux/slab.h>
  34
  35 #include <linux/acpi.h>
  36 #include <linux/io.h>
  37 #include <linux/spinlock.h>
  38 #include <linux/uaccess.h>
  39
  40 #include <acpi/processor.h>
  41
  42 #define PCC_VERSION     "1.00.00"
  43 #define POLL_LOOPS      300
  44
  45 #define CMD_COMPLETE    0x1
  46 #define CMD_GET_FREQ    0x0
  47 #define CMD_SET_FREQ    0x1
  48
  49 #define BUF_SZ          4
  50
  51 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER,      \
  52                                              "pcc-cpufreq", msg)
  53
  54 struct pcc_register_resource {
  55         u8 descriptor;
  56         u16 length;
  57         u8 space_id;
  58         u8 bit_width;
  59         u8 bit_offset;
  60         u8 access_size;
  61         u64 address;
  62 } __attribute__ ((packed));
  63
  64 struct pcc_memory_resource {
  65         u8 descriptor;
  66         u16 length;
  67         u8 space_id;
  68         u8 resource_usage;
  69         u8 type_specific;
  70         u64 granularity;
  71         u64 minimum;
  72         u64 maximum;
  73         u64 translation_offset;
  74         u64 address_length;
  75 } __attribute__ ((packed));
  76
  77 static struct cpufreq_driver pcc_cpufreq_driver;
  78
  79 struct pcc_header {
  80         u32 signature;
  81         u16 length;
  82         u8 major;
  83         u8 minor;
  84         u32 features;
  85         u16 command;
  86         u16 status;
  87         u32 latency;
  88         u32 minimum_time;
  89         u32 maximum_time;
  90         u32 nominal;
  91         u32 throttled_frequency;
  92         u32 minimum_frequency;
  93 };
  94
  95 static void __iomem *pcch_virt_addr;
  96 static struct pcc_header __iomem *pcch_hdr;
  97
  98 static DEFINE_SPINLOCK(pcc_lock);
  99
 100 static struct acpi_generic_address doorbell;
 101
 102 static u64 doorbell_preserve;
 103 static u64 doorbell_write;
 104
 105 static u8 OSC_UUID[16] = {0x63, 0x9B, 0x2C, 0x9F, 0x70, 0x91, 0x49, 0x1f,
 106                           0xBB, 0x4F, 0xA5, 0x98, 0x2F, 0xA1, 0xB5, 0x46};
 107
 108 struct pcc_cpu {
 109         u32 input_offset;
 110         u32 output_offset;
 111 };
 112
 113 static struct pcc_cpu __percpu *pcc_cpu_info;
 114
 115 static int pcc_cpufreq_verify(struct cpufreq_policy *policy)
 116 {
 117         cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
 118                                      policy->cpuinfo.max_freq);
 119         return 0;
 120 }
 121
 122 static inline void pcc_cmd(void)
 123 {
 124         u64 doorbell_value;
 125         int i;
 126
 127         acpi_read(&doorbell_value, &doorbell);
 128         acpi_write((doorbell_value & doorbell_preserve) | doorbell_write,
 129                    &doorbell);
 130
 131         for (i = 0; i < POLL_LOOPS; i++) {
 132                 if (ioread16(&pcch_hdr->status) & CMD_COMPLETE)
 133                         break;
 134         }
 135 }
 136
 137 static inline void pcc_clear_mapping(void)
 138 {
 139         if (pcch_virt_addr)
 140                 iounmap(pcch_virt_addr);
 141         pcch_virt_addr = NULL;
 142 }
 143
 144 static unsigned int pcc_get_freq(unsigned int cpu)
 145 {
 146         struct pcc_cpu *pcc_cpu_data;
 147         unsigned int curr_freq;
 148         unsigned int freq_limit;
 149         u16 status;
 150         u32 input_buffer;
 151         u32 output_buffer;
 152
 153         spin_lock(&pcc_lock);
 154
 155         dprintk("get: get_freq for CPU %d\n", cpu);
 156         pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu);
 157
 158         input_buffer = 0x1;
 159         iowrite32(input_buffer,
 160                         (pcch_virt_addr + pcc_cpu_data->input_offset));
 161         iowrite16(CMD_GET_FREQ, &pcch_hdr->command);
 162
 163         pcc_cmd();
 164
 165         output_buffer =
 166                 ioread32(pcch_virt_addr + pcc_cpu_data->output_offset);
 167
 168         /* Clear the input buffer - we are done with the current command */
 169         memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ);
 170
 171         status = ioread16(&pcch_hdr->status);
 172         if (status != CMD_COMPLETE) {
 173                 dprintk("get: FAILED: for CPU %d, status is %d\n",
 174                         cpu, status);
 175                 goto cmd_incomplete;
 176         }
 177         iowrite16(0, &pcch_hdr->status);
 178         curr_freq = (((ioread32(&pcch_hdr->nominal) * (output_buffer & 0xff))
 179                         / 100) * 1000);
 180
 181         dprintk("get: SUCCESS: (virtual) output_offset for cpu %d is "
 182                 "0x%x, contains a value of: 0x%x. Speed is: %d MHz\n",
 183                 cpu, (pcch_virt_addr + pcc_cpu_data->output_offset),
 184                 output_buffer, curr_freq);
 185
 186         freq_limit = (output_buffer >> 8) & 0xff;
 187         if (freq_limit != 0xff) {
 188                 dprintk("get: frequency for cpu %d is being temporarily"
 189                         " capped at %d\n", cpu, curr_freq);
 190         }
 191
 192         spin_unlock(&pcc_lock);
 193         return curr_freq;
 194
 195 cmd_incomplete:
 196         iowrite16(0, &pcch_hdr->status);
 197         spin_unlock(&pcc_lock);
 198         return -EINVAL;
 199 }
 200
 201 static int pcc_cpufreq_target(struct cpufreq_policy *policy,
 202                               unsigned int target_freq,
 203                               unsigned int relation)
 204 {
 205         struct pcc_cpu *pcc_cpu_data;
 206         struct cpufreq_freqs freqs;
 207         u16 status;
 208         u32 input_buffer;
 209         int cpu;
 210
 211         spin_lock(&pcc_lock);
 212         cpu = policy->cpu;
 213         pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu);
 214
 215         dprintk("target: CPU %d should go to target freq: %d "
 216                 "(virtual) input_offset is 0x%x\n",
 217                 cpu, target_freq,
 218                 (pcch_virt_addr + pcc_cpu_data->input_offset));
 219
 220         freqs.new = target_freq;
 221         freqs.cpu = cpu;
 222         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 223
 224         input_buffer = 0x1 | (((target_freq * 100)
 225                                / (ioread32(&pcch_hdr->nominal) * 1000)) << 8);
 226         iowrite32(input_buffer,
 227                         (pcch_virt_addr + pcc_cpu_data->input_offset));
 228         iowrite16(CMD_SET_FREQ, &pcch_hdr->command);
 229
 230         pcc_cmd();
 231
 232         /* Clear the input buffer - we are done with the current command */
 233         memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ);
 234
 235         status = ioread16(&pcch_hdr->status);
 236         if (status != CMD_COMPLETE) {
 237                 dprintk("target: FAILED for cpu %d, with status: 0x%x\n",
 238                         cpu, status);
 239                 goto cmd_incomplete;
 240         }
 241         iowrite16(0, &pcch_hdr->status);
 242
 243         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 244         dprintk("target: was SUCCESSFUL for cpu %d\n", cpu);
 245         spin_unlock(&pcc_lock);
 246
 247         return 0;
 248
 249 cmd_incomplete:
 250         iowrite16(0, &pcch_hdr->status);
 251         spin_unlock(&pcc_lock);
 252         return -EINVAL;
 253 }
 254
 255 static int pcc_get_offset(int cpu)
 256 {
 257         acpi_status status;
 258         struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
 259         union acpi_object *pccp, *offset;
 260         struct pcc_cpu *pcc_cpu_data;
 261         struct acpi_processor *pr;
 262         int ret = 0;
 263
 264         pr = per_cpu(processors, cpu);
 265         pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu);
 266
 267         status = acpi_evaluate_object(pr->handle, "PCCP", NULL, &buffer);
 268         if (ACPI_FAILURE(status))
 269                 return -ENODEV;
 270
 271         pccp = buffer.pointer;
 272         if (!pccp || pccp->type != ACPI_TYPE_PACKAGE) {
 273                 ret = -ENODEV;
 274                 goto out_free;
 275         };
 276
 277         offset = &(pccp->package.elements[0]);
 278         if (!offset || offset->type != ACPI_TYPE_INTEGER) {
 279                 ret = -ENODEV;
 280                 goto out_free;
 281         }
 282
 283         pcc_cpu_data->input_offset = offset->integer.value;
 284
 285         offset = &(pccp->package.elements[1]);
 286         if (!offset || offset->type != ACPI_TYPE_INTEGER) {
 287                 ret = -ENODEV;
 288                 goto out_free;
 289         }
 290
 291         pcc_cpu_data->output_offset = offset->integer.value;
 292
 293         memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ);
 294         memset_io((pcch_virt_addr + pcc_cpu_data->output_offset), 0, BUF_SZ);
 295
 296         dprintk("pcc_get_offset: for CPU %d: pcc_cpu_data "
 297                 "input_offset: 0x%x, pcc_cpu_data output_offset: 0x%x\n",
 298                 cpu, pcc_cpu_data->input_offset, pcc_cpu_data->output_offset);
 299 out_free:
 300         kfree(buffer.pointer);
 301         return ret;
 302 }
 303
 304 static int __init pcc_cpufreq_do_osc(acpi_handle *handle)
 305 {
 306         acpi_status status;
 307         struct acpi_object_list input;
 308         struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
 309         union acpi_object in_params[4];
 310         union acpi_object *out_obj;
 311         u32 capabilities[2];
 312         u32 errors;
 313         u32 supported;
 314         int ret = 0;
 315
 316         input.count = 4;
 317         input.pointer = in_params;
 318         input.count = 4;
 319         input.pointer = in_params;
 320         in_params[0].type               = ACPI_TYPE_BUFFER;
 321         in_params[0].buffer.length      = 16;
 322         in_params[0].buffer.pointer     = OSC_UUID;
 323         in_params[1].type               = ACPI_TYPE_INTEGER;
 324         in_params[1].integer.value      = 1;
 325         in_params[2].type               = ACPI_TYPE_INTEGER;
 326         in_params[2].integer.value      = 2;
 327         in_params[3].type               = ACPI_TYPE_BUFFER;
 328         in_params[3].buffer.length      = 8;
 329         in_params[3].buffer.pointer     = (u8 *)&capabilities;
 330
 331         capabilities[0] = OSC_QUERY_ENABLE;
 332         capabilities[1] = 0x1;
 333
 334         status = acpi_evaluate_object(*handle, "_OSC", &input, &output);
 335         if (ACPI_FAILURE(status))
 336                 return -ENODEV;
 337
 338         if (!output.length)
 339                 return -ENODEV;
 340
 341         out_obj = output.pointer;
 342         if (out_obj->type != ACPI_TYPE_BUFFER) {
 343                 ret = -ENODEV;
 344                 goto out_free;
 345         }
 346
 347         errors = *((u32 *)out_obj->buffer.pointer) & ~(1 << 0);
 348         if (errors) {
 349                 ret = -ENODEV;
 350                 goto out_free;
 351         }
 352
 353         supported = *((u32 *)(out_obj->buffer.pointer + 4));
 354         if (!(supported & 0x1)) {
 355                 ret = -ENODEV;
 356                 goto out_free;
 357         }
 358
 359         kfree(output.pointer);
 360         capabilities[0] = 0x0;
 361         capabilities[1] = 0x1;
 362
 363         status = acpi_evaluate_object(*handle, "_OSC", &input, &output);
 364         if (ACPI_FAILURE(status))
 365                 return -ENODEV;
 366
 367         if (!output.length)
 368                 return -ENODEV;
 369
 370         out_obj = output.pointer;
 371         if (out_obj->type != ACPI_TYPE_BUFFER) {
 372                 ret = -ENODEV;
 373                 goto out_free;
 374         }
 375
 376         errors = *((u32 *)out_obj->buffer.pointer) & ~(1 << 0);
 377         if (errors) {
 378                 ret = -ENODEV;
 379                 goto out_free;
 380         }
 381
 382         supported = *((u32 *)(out_obj->buffer.pointer + 4));
 383         if (!(supported & 0x1)) {
 384                 ret = -ENODEV;
 385                 goto out_free;
 386         }
 387
 388 out_free:
 389         kfree(output.pointer);
 390         return ret;
 391 }
 392
 393 static int __init pcc_cpufreq_probe(void)
 394 {
 395         acpi_status status;
 396         struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
 397         struct pcc_memory_resource *mem_resource;
 398         struct pcc_register_resource *reg_resource;
 399         union acpi_object *out_obj, *member;
 400         acpi_handle handle, osc_handle, pcch_handle;
 401         int ret = 0;
 402
 403         status = acpi_get_handle(NULL, "\\_SB", &handle);
 404         if (ACPI_FAILURE(status))
 405                 return -ENODEV;
 406
 407         status = acpi_get_handle(handle, "PCCH", &pcch_handle);
 408         if (ACPI_FAILURE(status))
 409                 return -ENODEV;
 410
 411         status = acpi_get_handle(handle, "_OSC", &osc_handle);
 412         if (ACPI_SUCCESS(status)) {
 413                 ret = pcc_cpufreq_do_osc(&osc_handle);
 414                 if (ret)
 415                         dprintk("probe: _OSC evaluation did not succeed\n");
 416                 /* Firmware's use of _OSC is optional */
 417                 ret = 0;
 418         }
 419
 420         status = acpi_evaluate_object(handle, "PCCH", NULL, &output);
 421         if (ACPI_FAILURE(status))
 422                 return -ENODEV;
 423
 424         out_obj = output.pointer;
 425         if (out_obj->type != ACPI_TYPE_PACKAGE) {
 426                 ret = -ENODEV;
 427                 goto out_free;
 428         }
 429
 430         member = &out_obj->package.elements[0];
 431         if (member->type != ACPI_TYPE_BUFFER) {
 432                 ret = -ENODEV;
 433                 goto out_free;
 434         }
 435
 436         mem_resource = (struct pcc_memory_resource *)member->buffer.pointer;
 437
 438         dprintk("probe: mem_resource descriptor: 0x%x,"
 439                 " length: %d, space_id: %d, resource_usage: %d,"
 440                 " type_specific: %d, granularity: 0x%llx,"
 441                 " minimum: 0x%llx, maximum: 0x%llx,"
 442                 " translation_offset: 0x%llx, address_length: 0x%llx\n",
 443                 mem_resource->descriptor, mem_resource->length,
 444                 mem_resource->space_id, mem_resource->resource_usage,
 445                 mem_resource->type_specific, mem_resource->granularity,
 446                 mem_resource->minimum, mem_resource->maximum,
 447                 mem_resource->translation_offset,
 448                 mem_resource->address_length);
 449
 450         if (mem_resource->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY) {
 451                 ret = -ENODEV;
 452                 goto out_free;
 453         }
 454
 455         pcch_virt_addr = ioremap_nocache(mem_resource->minimum,
 456                                         mem_resource->address_length);
 457         if (pcch_virt_addr == NULL) {
 458                 dprintk("probe: could not map shared mem region\n");
 459                 goto out_free;
 460         }
 461         pcch_hdr = pcch_virt_addr;
 462
 463         dprintk("probe: PCCH header (virtual) addr: 0x%p\n", pcch_hdr);
 464         dprintk("probe: PCCH header is at physical address: 0x%llx,"
 465                 " signature: 0x%x, length: %d bytes, major: %d, minor: %d,"
 466                 " supported features: 0x%x, command field: 0x%x,"
 467                 " status field: 0x%x, nominal latency: %d us\n",
 468                 mem_resource->minimum, ioread32(&pcch_hdr->signature),
 469                 ioread16(&pcch_hdr->length), ioread8(&pcch_hdr->major),
 470                 ioread8(&pcch_hdr->minor), ioread32(&pcch_hdr->features),
 471                 ioread16(&pcch_hdr->command), ioread16(&pcch_hdr->status),
 472                 ioread32(&pcch_hdr->latency));
 473
 474         dprintk("probe: min time between commands: %d us,"
 475                 " max time between commands: %d us,"
 476                 " nominal CPU frequency: %d MHz,"
 477                 " minimum CPU frequency: %d MHz,"
 478                 " minimum CPU frequency without throttling: %d MHz\n",
 479                 ioread32(&pcch_hdr->minimum_time),
 480                 ioread32(&pcch_hdr->maximum_time),
 481                 ioread32(&pcch_hdr->nominal),
 482                 ioread32(&pcch_hdr->throttled_frequency),
 483                 ioread32(&pcch_hdr->minimum_frequency));
 484
 485         member = &out_obj->package.elements[1];
 486         if (member->type != ACPI_TYPE_BUFFER) {
 487                 ret = -ENODEV;
 488                 goto pcch_free;
 489         }
 490
 491         reg_resource = (struct pcc_register_resource *)member->buffer.pointer;
 492
 493         doorbell.space_id = reg_resource->space_id;
 494         doorbell.bit_width = reg_resource->bit_width;
 495         doorbell.bit_offset = reg_resource->bit_offset;
 496         doorbell.access_width = 64;
 497         doorbell.address = reg_resource->address;
 498
 499         dprintk("probe: doorbell: space_id is %d, bit_width is %d, "
 500                 "bit_offset is %d, access_width is %d, address is 0x%llx\n",
 501                 doorbell.space_id, doorbell.bit_width, doorbell.bit_offset,
 502                 doorbell.access_width, reg_resource->address);
 503
 504         member = &out_obj->package.elements[2];
 505         if (member->type != ACPI_TYPE_INTEGER) {
 506                 ret = -ENODEV;
 507                 goto pcch_free;
 508         }
 509
 510         doorbell_preserve = member->integer.value;
 511
 512         member = &out_obj->package.elements[3];
 513         if (member->type != ACPI_TYPE_INTEGER) {
 514                 ret = -ENODEV;
 515                 goto pcch_free;
 516         }
 517
 518         doorbell_write = member->integer.value;
 519
 520         dprintk("probe: doorbell_preserve: 0x%llx,"
 521                 " doorbell_write: 0x%llx\n",
 522                 doorbell_preserve, doorbell_write);
 523
 524         pcc_cpu_info = alloc_percpu(struct pcc_cpu);
 525         if (!pcc_cpu_info) {
 526                 ret = -ENOMEM;
 527                 goto pcch_free;
 528         }
 529
 530         printk(KERN_DEBUG "pcc-cpufreq: (v%s) driver loaded with frequency"
 531                " limits: %d MHz, %d MHz\n", PCC_VERSION,
 532                ioread32(&pcch_hdr->minimum_frequency),
 533                ioread32(&pcch_hdr->nominal));
 534         kfree(output.pointer);
 535         return ret;
 536 pcch_free:
 537         pcc_clear_mapping();
 538 out_free:
 539         kfree(output.pointer);
 540         return ret;
 541 }
 542
 543 static int pcc_cpufreq_cpu_init(struct cpufreq_policy *policy)
 544 {
 545         unsigned int cpu = policy->cpu;
 546         unsigned int result = 0;
 547
 548         if (!pcch_virt_addr) {
 549                 result = -1;
 550                 goto out;
 551         }
 552
 553         result = pcc_get_offset(cpu);
 554         if (result) {
 555                 dprintk("init: PCCP evaluation failed\n");
 556                 goto out;
 557         }
 558
 559         policy->max = policy->cpuinfo.max_freq =
 560                 ioread32(&pcch_hdr->nominal) * 1000;
 561         policy->min = policy->cpuinfo.min_freq =
 562                 ioread32(&pcch_hdr->minimum_frequency) * 1000;
 563         policy->cur = pcc_get_freq(cpu);
 564
 565         if (!policy->cur) {
 566                 dprintk("init: Unable to get current CPU frequency\n");
 567                 result = -EINVAL;
 568                 goto out;
 569         }
 570
 571         dprintk("init: policy->max is %d, policy->min is %d\n",
 572                 policy->max, policy->min);
 573 out:
 574         return result;
 575 }
 576
 577 static int pcc_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 578 {
 579         return 0;
 580 }
 581
 582 static struct cpufreq_driver pcc_cpufreq_driver = {
 583         .flags = CPUFREQ_CONST_LOOPS,
 584         .get = pcc_get_freq,
 585         .verify = pcc_cpufreq_verify,
 586         .target = pcc_cpufreq_target,
 587         .init = pcc_cpufreq_cpu_init,
 588         .exit = pcc_cpufreq_cpu_exit,
 589         .name = "pcc-cpufreq",
 590         .owner = THIS_MODULE,
 591 };
 592
 593 static int __init pcc_cpufreq_init(void)
 594 {
 595         int ret;
 596
 597         if (acpi_disabled)
 598                 return 0;
 599
 600         ret = pcc_cpufreq_probe();
 601         if (ret) {
 602                 dprintk("pcc_cpufreq_init: PCCH evaluation failed\n");
 603                 return ret;
 604         }
 605
 606         ret = cpufreq_register_driver(&pcc_cpufreq_driver);
 607
 608         return ret;
 609 }
 610
 611 static void __exit pcc_cpufreq_exit(void)
 612 {
 613         cpufreq_unregister_driver(&pcc_cpufreq_driver);
 614
 615         pcc_clear_mapping();
 616
 617         free_percpu(pcc_cpu_info);
 618 }
 619
 620 MODULE_AUTHOR("Matthew Garrett, Naga Chumbalkar");
 621 MODULE_VERSION(PCC_VERSION);
 622 MODULE_DESCRIPTION("Processor Clocking Control interface driver");
 623 MODULE_LICENSE("GPL");
 624
 625 late_initcall(pcc_cpufreq_init);
 626 module_exit(pcc_cpufreq_exit);