Free Electrons

Embedded Linux Experts

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
/*
 * Copyright 2012 by Oracle Inc
 * Author: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
 *
 * This code borrows ideas from https://lkml.org/lkml/2011/11/30/249
 * so many thanks go to Kevin Tian <kevin.tian@intel.com>
 * and Yu Ke <ke.yu@intel.com>.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 */

#include <linux/cpumask.h>
#include <linux/cpufreq.h>
#include <linux/freezer.h>
#include <linux/kernel.h>
#include <linux/kthread.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/types.h>
#include <acpi/acpi_bus.h>
#include <acpi/acpi_drivers.h>
#include <acpi/processor.h>

#include <xen/interface/platform.h>
#include <asm/xen/hypercall.h>

#define DRV_NAME "xen-acpi-processor: "

static int no_hypercall;
MODULE_PARM_DESC(off, "Inhibit the hypercall.");
module_param_named(off, no_hypercall, int, 0400);

/*
 * Note: Do not convert the acpi_id* below to cpumask_var_t or use cpumask_bit
 * - as those shrink to nr_cpu_bits (which is dependent on possible_cpu), which
 * can be less than what we want to put in. Instead use the 'nr_acpi_bits'
 * which is dynamically computed based on the MADT or x2APIC table.
 */
static unsigned int nr_acpi_bits;
/* Mutex to protect the acpi_ids_done - for CPU hotplug use. */
static DEFINE_MUTEX(acpi_ids_mutex);
/* Which ACPI ID we have processed from 'struct acpi_processor'. */
static unsigned long *acpi_ids_done;
/* Which ACPI ID exist in the SSDT/DSDT processor definitions. */
static unsigned long __initdata *acpi_id_present;
/* And if there is an _CST definition (or a PBLK) for the ACPI IDs */
static unsigned long __initdata *acpi_id_cst_present;

static int push_cxx_to_hypervisor(struct acpi_processor *_pr)
{
	struct xen_platform_op op = {
		.cmd			= XENPF_set_processor_pminfo,
		.interface_version	= XENPF_INTERFACE_VERSION,
		.u.set_pminfo.id	= _pr->acpi_id,
		.u.set_pminfo.type	= XEN_PM_CX,
	};
	struct xen_processor_cx *dst_cx, *dst_cx_states = NULL;
	struct acpi_processor_cx *cx;
	unsigned int i, ok;
	int ret = 0;

	dst_cx_states = kcalloc(_pr->power.count,
				sizeof(struct xen_processor_cx), GFP_KERNEL);
	if (!dst_cx_states)
		return -ENOMEM;

	for (ok = 0, i = 1; i <= _pr->power.count; i++) {
		cx = &_pr->power.states[i];
		if (!cx->valid)
			continue;

		dst_cx = &(dst_cx_states[ok++]);

		dst_cx->reg.space_id = ACPI_ADR_SPACE_SYSTEM_IO;
		if (cx->entry_method == ACPI_CSTATE_SYSTEMIO) {
			dst_cx->reg.bit_width = 8;
			dst_cx->reg.bit_offset = 0;
			dst_cx->reg.access_size = 1;
		} else {
			dst_cx->reg.space_id = ACPI_ADR_SPACE_FIXED_HARDWARE;
			if (cx->entry_method == ACPI_CSTATE_FFH) {
				/* NATIVE_CSTATE_BEYOND_HALT */
				dst_cx->reg.bit_offset = 2;
				dst_cx->reg.bit_width = 1; /* VENDOR_INTEL */
			}
			dst_cx->reg.access_size = 0;
		}
		dst_cx->reg.address = cx->address;

		dst_cx->type = cx->type;
		dst_cx->latency = cx->latency;
		dst_cx->power = cx->power;

		dst_cx->dpcnt = 0;
		set_xen_guest_handle(dst_cx->dp, NULL);
	}
	if (!ok) {
		pr_debug(DRV_NAME "No _Cx for ACPI CPU %u\n", _pr->acpi_id);
		kfree(dst_cx_states);
		return -EINVAL;
	}
	op.u.set_pminfo.power.count = ok;
	op.u.set_pminfo.power.flags.bm_control = _pr->flags.bm_control;
	op.u.set_pminfo.power.flags.bm_check = _pr->flags.bm_check;
	op.u.set_pminfo.power.flags.has_cst = _pr->flags.has_cst;
	op.u.set_pminfo.power.flags.power_setup_done =
		_pr->flags.power_setup_done;

	set_xen_guest_handle(op.u.set_pminfo.power.states, dst_cx_states);

	if (!no_hypercall)
		ret = HYPERVISOR_dom0_op(&op);

	if (!ret) {
		pr_debug("ACPI CPU%u - C-states uploaded.\n", _pr->acpi_id);
		for (i = 1; i <= _pr->power.count; i++) {
			cx = &_pr->power.states[i];
			if (!cx->valid)
				continue;
			pr_debug("     C%d: %s %d uS\n",
				 cx->type, cx->desc, (u32)cx->latency);
		}
	} else if (ret != -EINVAL)
		/* EINVAL means the ACPI ID is incorrect - meaning the ACPI
		 * table is referencing a non-existing CPU - which can happen
		 * with broken ACPI tables. */
		pr_err(DRV_NAME "(CX): Hypervisor error (%d) for ACPI CPU%u\n",
		       ret, _pr->acpi_id);

	kfree(dst_cx_states);

	return ret;
}
static struct xen_processor_px *
xen_copy_pss_data(struct acpi_processor *_pr,
		  struct xen_processor_performance *dst_perf)
{
	struct xen_processor_px *dst_states = NULL;
	unsigned int i;

	BUILD_BUG_ON(sizeof(struct xen_processor_px) !=
		     sizeof(struct acpi_processor_px));

	dst_states = kcalloc(_pr->performance->state_count,
			     sizeof(struct xen_processor_px), GFP_KERNEL);
	if (!dst_states)
		return ERR_PTR(-ENOMEM);

	dst_perf->state_count = _pr->performance->state_count;
	for (i = 0; i < _pr->performance->state_count; i++) {
		/* Fortunatly for us, they are both the same size */
		memcpy(&(dst_states[i]), &(_pr->performance->states[i]),
		       sizeof(struct acpi_processor_px));
	}
	return dst_states;
}
static int xen_copy_psd_data(struct acpi_processor *_pr,
			     struct xen_processor_performance *dst)
{
	struct acpi_psd_package *pdomain;

	BUILD_BUG_ON(sizeof(struct xen_psd_package) !=
		     sizeof(struct acpi_psd_package));

	/* This information is enumerated only if acpi_processor_preregister_performance
	 * has been called.
	 */
	dst->shared_type = _pr->performance->shared_type;

	pdomain = &(_pr->performance->domain_info);

	/* 'acpi_processor_preregister_performance' does not parse if the
	 * num_processors <= 1, but Xen still requires it. Do it manually here.
	 */
	if (pdomain->num_processors <= 1) {
		if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ALL)
			dst->shared_type = CPUFREQ_SHARED_TYPE_ALL;
		else if (pdomain->coord_type == DOMAIN_COORD_TYPE_HW_ALL)
			dst->shared_type = CPUFREQ_SHARED_TYPE_HW;
		else if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ANY)
			dst->shared_type = CPUFREQ_SHARED_TYPE_ANY;

	}
	memcpy(&(dst->domain_info), pdomain, sizeof(struct acpi_psd_package));
	return 0;
}
static int xen_copy_pct_data(struct acpi_pct_register *pct,
			     struct xen_pct_register *dst_pct)
{
	/* It would be nice if you could just do 'memcpy(pct, dst_pct') but
	 * sadly the Xen structure did not have the proper padding so the
	 * descriptor field takes two (dst_pct) bytes instead of one (pct).
	 */
	dst_pct->descriptor = pct->descriptor;
	dst_pct->length = pct->length;
	dst_pct->space_id = pct->space_id;
	dst_pct->bit_width = pct->bit_width;
	dst_pct->bit_offset = pct->bit_offset;
	dst_pct->reserved = pct->reserved;
	dst_pct->address = pct->address;
	return 0;
}
static int push_pxx_to_hypervisor(struct acpi_processor *_pr)
{
	int ret = 0;
	struct xen_platform_op op = {
		.cmd			= XENPF_set_processor_pminfo,
		.interface_version	= XENPF_INTERFACE_VERSION,
		.u.set_pminfo.id	= _pr->acpi_id,
		.u.set_pminfo.type	= XEN_PM_PX,
	};
	struct xen_processor_performance *dst_perf;
	struct xen_processor_px *dst_states = NULL;

	dst_perf = &op.u.set_pminfo.perf;

	dst_perf->platform_limit = _pr->performance_platform_limit;
	dst_perf->flags |= XEN_PX_PPC;
	xen_copy_pct_data(&(_pr->performance->control_register),
			  &dst_perf->control_register);
	xen_copy_pct_data(&(_pr->performance->status_register),
			  &dst_perf->status_register);
	dst_perf->flags |= XEN_PX_PCT;
	dst_states = xen_copy_pss_data(_pr, dst_perf);
	if (!IS_ERR_OR_NULL(dst_states)) {
		set_xen_guest_handle(dst_perf->states, dst_states);
		dst_perf->flags |= XEN_PX_PSS;
	}
	if (!xen_copy_psd_data(_pr, dst_perf))
		dst_perf->flags |= XEN_PX_PSD;

	if (dst_perf->flags != (XEN_PX_PSD | XEN_PX_PSS | XEN_PX_PCT | XEN_PX_PPC)) {
		pr_warn(DRV_NAME "ACPI CPU%u missing some P-state data (%x), skipping.\n",
			_pr->acpi_id, dst_perf->flags);
		ret = -ENODEV;
		goto err_free;
	}

	if (!no_hypercall)
		ret = HYPERVISOR_dom0_op(&op);

	if (!ret) {
		struct acpi_processor_performance *perf;
		unsigned int i;

		perf = _pr->performance;
		pr_debug("ACPI CPU%u - P-states uploaded.\n", _pr->acpi_id);
		for (i = 0; i < perf->state_count; i++) {
			pr_debug("     %cP%d: %d MHz, %d mW, %d uS\n",
			(i == perf->state ? '*' : ' '), i,
			(u32) perf->states[i].core_frequency,
			(u32) perf->states[i].power,
			(u32) perf->states[i].transition_latency);
		}
	} else if (ret != -EINVAL)
		/* EINVAL means the ACPI ID is incorrect - meaning the ACPI
		 * table is referencing a non-existing CPU - which can happen
		 * with broken ACPI tables. */
		pr_warn(DRV_NAME "(_PXX): Hypervisor error (%d) for ACPI CPU%u\n",
		       ret, _pr->acpi_id);
err_free:
	if (!IS_ERR_OR_NULL(dst_states))
		kfree(dst_states);

	return ret;
}
static int upload_pm_data(struct acpi_processor *_pr)
{
	int err = 0;

	mutex_lock(&acpi_ids_mutex);
	if (__test_and_set_bit(_pr->acpi_id, acpi_ids_done)) {
		mutex_unlock(&acpi_ids_mutex);
		return -EBUSY;
	}
	if (_pr->flags.power)
		err = push_cxx_to_hypervisor(_pr);

	if (_pr->performance && _pr->performance->states)
		err |= push_pxx_to_hypervisor(_pr);

	mutex_unlock(&acpi_ids_mutex);
	return err;
}
static unsigned int __init get_max_acpi_id(void)
{
	struct xenpf_pcpuinfo *info;
	struct xen_platform_op op = {
		.cmd = XENPF_get_cpuinfo,
		.interface_version = XENPF_INTERFACE_VERSION,
	};
	int ret = 0;
	unsigned int i, last_cpu, max_acpi_id = 0;

	info = &op.u.pcpu_info;
	info->xen_cpuid = 0;

	ret = HYPERVISOR_dom0_op(&op);
	if (ret)
		return NR_CPUS;

	/* The max_present is the same irregardless of the xen_cpuid */
	last_cpu = op.u.pcpu_info.max_present;
	for (i = 0; i <= last_cpu; i++) {
		info->xen_cpuid = i;
		ret = HYPERVISOR_dom0_op(&op);
		if (ret)
			continue;
		max_acpi_id = max(info->acpi_id, max_acpi_id);
	}
	max_acpi_id *= 2; /* Slack for CPU hotplug support. */
	pr_debug(DRV_NAME "Max ACPI ID: %u\n", max_acpi_id);
	return max_acpi_id;
}
/*
 * The read_acpi_id and check_acpi_ids are there to support the Xen
 * oddity of virtual CPUs != physical CPUs in the initial domain.
 * The user can supply 'xen_max_vcpus=X' on the Xen hypervisor line
 * which will band the amount of CPUs the initial domain can see.
 * In general that is OK, except it plays havoc with any of the
 * for_each_[present|online]_cpu macros which are banded to the virtual
 * CPU amount.
 */
static acpi_status __init
read_acpi_id(acpi_handle handle, u32 lvl, void *context, void **rv)
{
	u32 acpi_id;
	acpi_status status;
	acpi_object_type acpi_type;
	unsigned long long tmp;
	union acpi_object object = { 0 };
	struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
	acpi_io_address pblk = 0;

	status = acpi_get_type(handle, &acpi_type);
	if (ACPI_FAILURE(status))
		return AE_OK;

	switch (acpi_type) {
	case ACPI_TYPE_PROCESSOR:
		status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
		if (ACPI_FAILURE(status))
			return AE_OK;
		acpi_id = object.processor.proc_id;
		pblk = object.processor.pblk_address;
		break;
	case ACPI_TYPE_DEVICE:
		status = acpi_evaluate_integer(handle, "_UID", NULL, &tmp);
		if (ACPI_FAILURE(status))
			return AE_OK;
		acpi_id = tmp;
		break;
	default:
		return AE_OK;
	}
	/* There are more ACPI Processor objects than in x2APIC or MADT.
	 * This can happen with incorrect ACPI SSDT declerations. */
	if (acpi_id > nr_acpi_bits) {
		pr_debug(DRV_NAME "We only have %u, trying to set %u\n",
			 nr_acpi_bits, acpi_id);
		return AE_OK;
	}
	/* OK, There is a ACPI Processor object */
	__set_bit(acpi_id, acpi_id_present);

	pr_debug(DRV_NAME "ACPI CPU%u w/ PBLK:0x%lx\n", acpi_id,
		 (unsigned long)pblk);

	status = acpi_evaluate_object(handle, "_CST", NULL, &buffer);
	if (ACPI_FAILURE(status)) {
		if (!pblk)
			return AE_OK;
	}
	/* .. and it has a C-state */
	__set_bit(acpi_id, acpi_id_cst_present);

	return AE_OK;
}
static int __init check_acpi_ids(struct acpi_processor *pr_backup)
{

	if (!pr_backup)
		return -ENODEV;

	/* All online CPUs have been processed at this stage. Now verify
	 * whether in fact "online CPUs" == physical CPUs.
	 */
	acpi_id_present = kcalloc(BITS_TO_LONGS(nr_acpi_bits), sizeof(unsigned long), GFP_KERNEL);
	if (!acpi_id_present)
		return -ENOMEM;

	acpi_id_cst_present = kcalloc(BITS_TO_LONGS(nr_acpi_bits), sizeof(unsigned long), GFP_KERNEL);
	if (!acpi_id_cst_present) {
		kfree(acpi_id_present);
		return -ENOMEM;
	}

	acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
			    ACPI_UINT32_MAX,
			    read_acpi_id, NULL, NULL, NULL);
	acpi_get_devices("ACPI0007", read_acpi_id, NULL, NULL);

	if (!bitmap_equal(acpi_id_present, acpi_ids_done, nr_acpi_bits)) {
		unsigned int i;
		for_each_set_bit(i, acpi_id_present, nr_acpi_bits) {
			pr_backup->acpi_id = i;
			/* Mask out C-states if there are no _CST or PBLK */
			pr_backup->flags.power = test_bit(i, acpi_id_cst_present);
			(void)upload_pm_data(pr_backup);
		}
	}
	kfree(acpi_id_present);
	acpi_id_present = NULL;
	kfree(acpi_id_cst_present);
	acpi_id_cst_present = NULL;
	return 0;
}
static int __init check_prereq(void)
{
	struct cpuinfo_x86 *c = &cpu_data(0);

	if (!xen_initial_domain())
		return -ENODEV;

	if (!acpi_gbl_FADT.smi_command)
		return -ENODEV;

	if (c->x86_vendor == X86_VENDOR_INTEL) {
		if (!cpu_has(c, X86_FEATURE_EST))
			return -ENODEV;

		return 0;
	}
	if (c->x86_vendor == X86_VENDOR_AMD) {
		/* Copied from powernow-k8.h, can't include ../cpufreq/powernow
		 * as we get compile warnings for the static functions.
		 */
#define CPUID_FREQ_VOLT_CAPABILITIES    0x80000007
#define USE_HW_PSTATE                   0x00000080
		u32 eax, ebx, ecx, edx;
		cpuid(CPUID_FREQ_VOLT_CAPABILITIES, &eax, &ebx, &ecx, &edx);
		if ((edx & USE_HW_PSTATE) != USE_HW_PSTATE)
			return -ENODEV;
		return 0;
	}
	return -ENODEV;
}
/* acpi_perf_data is a pointer to percpu data. */
static struct acpi_processor_performance __percpu *acpi_perf_data;

static void free_acpi_perf_data(void)
{
	unsigned int i;

	/* Freeing a NULL pointer is OK, and alloc_percpu zeroes. */
	for_each_possible_cpu(i)
		free_cpumask_var(per_cpu_ptr(acpi_perf_data, i)
				 ->shared_cpu_map);
	free_percpu(acpi_perf_data);
}

static int __init xen_acpi_processor_init(void)
{
	struct acpi_processor *pr_backup = NULL;
	unsigned int i;
	int rc = check_prereq();

	if (rc)
		return rc;

	nr_acpi_bits = get_max_acpi_id() + 1;
	acpi_ids_done = kcalloc(BITS_TO_LONGS(nr_acpi_bits), sizeof(unsigned long), GFP_KERNEL);
	if (!acpi_ids_done)
		return -ENOMEM;

	acpi_perf_data = alloc_percpu(struct acpi_processor_performance);
	if (!acpi_perf_data) {
		pr_debug(DRV_NAME "Memory allocation error for acpi_perf_data.\n");
		kfree(acpi_ids_done);
		return -ENOMEM;
	}
	for_each_possible_cpu(i) {
		if (!zalloc_cpumask_var_node(
			&per_cpu_ptr(acpi_perf_data, i)->shared_cpu_map,
			GFP_KERNEL, cpu_to_node(i))) {
			rc = -ENOMEM;
			goto err_out;
		}
	}

	/* Do initialization in ACPI core. It is OK to fail here. */
	(void)acpi_processor_preregister_performance(acpi_perf_data);

	for_each_possible_cpu(i) {
		struct acpi_processor_performance *perf;

		perf = per_cpu_ptr(acpi_perf_data, i);
		rc = acpi_processor_register_performance(perf, i);
		if (rc)
			goto err_out;
	}
	rc = acpi_processor_notify_smm(THIS_MODULE);
	if (rc)
		goto err_unregister;

	for_each_possible_cpu(i) {
		struct acpi_processor *_pr;
		_pr = per_cpu(processors, i /* APIC ID */);
		if (!_pr)
			continue;

		if (!pr_backup) {
			pr_backup = kzalloc(sizeof(struct acpi_processor), GFP_KERNEL);
			memcpy(pr_backup, _pr, sizeof(struct acpi_processor));
		}
		(void)upload_pm_data(_pr);
	}
	rc = check_acpi_ids(pr_backup);
	if (rc)
		goto err_unregister;

	kfree(pr_backup);

	return 0;
err_unregister:
	for_each_possible_cpu(i) {
		struct acpi_processor_performance *perf;
		perf = per_cpu_ptr(acpi_perf_data, i);
		acpi_processor_unregister_performance(perf, i);
	}
err_out:
	/* Freeing a NULL pointer is OK: alloc_percpu zeroes. */
	free_acpi_perf_data();
	kfree(acpi_ids_done);
	return rc;
}
static void __exit xen_acpi_processor_exit(void)
{
	int i;

	kfree(acpi_ids_done);
	for_each_possible_cpu(i) {
		struct acpi_processor_performance *perf;
		perf = per_cpu_ptr(acpi_perf_data, i);
		acpi_processor_unregister_performance(perf, i);
	}
	free_acpi_perf_data();
}

MODULE_AUTHOR("Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>");
MODULE_DESCRIPTION("Xen ACPI Processor P-states (and Cx) driver which uploads PM data to Xen hypervisor");
MODULE_LICENSE("GPL");

/* We want to be loaded before the CPU freq scaling drivers are loaded.
 * They are loaded in late_initcall. */
device_initcall(xen_acpi_processor_init);
module_exit(xen_acpi_processor_exit);