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git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Revert "ACPI: processor: idle: Optimize ACPI idle driver registration"
Revert commit 7a8c994cbb2d ("ACPI: processor: idle: Optimize ACPI idle
driver registration") because it is reported to introduce a cpuidle
regression leading to a kernel crash on a platform using the ACPI idle
driver.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reported-by: Borislav Petkov <bp@alien8.de>
Tested-by: Borislav Petkov (AMD) <bp@alien8.de>
Closes: https://lore.kernel.org/lkml/20251124200019.GIaSS5U9HhsWBotrQZ@fat_crate.local/
+23
-47
-3
drivers/acpi/processor_driver.c
-3
drivers/acpi/processor_driver.c
···
263
263
if (result < 0)
264
264
return result;
265
265
266
-
acpi_processor_register_idle_driver();
267
-
268
266
result = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,
269
267
"acpi/cpu-drv:online",
270
268
acpi_soft_cpu_online, NULL);
···
301
303
302
304
cpuhp_remove_state_nocalls(hp_online);
303
305
cpuhp_remove_state_nocalls(CPUHP_ACPI_CPUDRV_DEAD);
304
-
acpi_processor_unregister_idle_driver();
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driver_unregister(&acpi_processor_driver);
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}
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308
+23
-42
drivers/acpi/processor_idle.c
+23
-42
drivers/acpi/processor_idle.c
···
1357
1357
return 0;
1358
1358
}
1359
1359
1360
-
void acpi_processor_register_idle_driver(void)
1361
-
{
1362
-
struct acpi_processor *pr;
1363
-
int ret = -ENODEV;
1364
-
int cpu;
1365
-
1366
-
/*
1367
-
* Acpi idle driver is used by all possible CPUs.
1368
-
* Install the idle handler by the processor power info of one in them.
1369
-
* Note that we use previously set idle handler will be used on
1370
-
* platforms that only support C1.
1371
-
*/
1372
-
for_each_cpu(cpu, (struct cpumask *)cpu_possible_mask) {
1373
-
pr = per_cpu(processors, cpu);
1374
-
if (!pr)
1375
-
continue;
1376
-
1377
-
ret = acpi_processor_get_power_info(pr);
1378
-
if (!ret) {
1379
-
pr->flags.power_setup_done = 1;
1380
-
acpi_processor_setup_cpuidle_states(pr);
1381
-
break;
1382
-
}
1383
-
}
1384
-
1385
-
if (ret) {
1386
-
pr_debug("No ACPI power information from any CPUs.\n");
1387
-
return;
1388
-
}
1389
-
1390
-
ret = cpuidle_register_driver(&acpi_idle_driver);
1391
-
if (ret) {
1392
-
pr_debug("register %s failed.\n", acpi_idle_driver.name);
1393
-
return;
1394
-
}
1395
-
pr_debug("%s registered with cpuidle.\n", acpi_idle_driver.name);
1396
-
}
1397
-
1398
-
void acpi_processor_unregister_idle_driver(void)
1399
-
{
1400
-
cpuidle_unregister_driver(&acpi_idle_driver);
1401
-
}
1360
+
static int acpi_processor_registered;
1402
1361
1403
1362
int acpi_processor_power_init(struct acpi_processor *pr)
1404
1363
{
···
1372
1413
if (!acpi_processor_get_power_info(pr))
1373
1414
pr->flags.power_setup_done = 1;
1374
1415
1416
+
/*
1417
+
* Install the idle handler if processor power management is supported.
1418
+
* Note that we use previously set idle handler will be used on
1419
+
* platforms that only support C1.
1420
+
*/
1375
1421
if (pr->flags.power) {
1422
+
/* Register acpi_idle_driver if not already registered */
1423
+
if (!acpi_processor_registered) {
1424
+
acpi_processor_setup_cpuidle_states(pr);
1425
+
retval = cpuidle_register_driver(&acpi_idle_driver);
1426
+
if (retval)
1427
+
return retval;
1428
+
pr_debug("%s registered with cpuidle\n",
1429
+
acpi_idle_driver.name);
1430
+
}
1431
+
1376
1432
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1377
1433
if (!dev)
1378
1434
return -ENOMEM;
···
1400
1426
*/
1401
1427
retval = cpuidle_register_device(dev);
1402
1428
if (retval) {
1429
+
if (acpi_processor_registered == 0)
1430
+
cpuidle_unregister_driver(&acpi_idle_driver);
1403
1431
1404
1432
per_cpu(acpi_cpuidle_device, pr->id) = NULL;
1405
1433
kfree(dev);
1406
1434
return retval;
1407
1435
}
1436
+
acpi_processor_registered++;
1408
1437
}
1409
1438
return 0;
1410
1439
}
···
1421
1444
1422
1445
if (pr->flags.power) {
1423
1446
cpuidle_unregister_device(dev);
1447
+
acpi_processor_registered--;
1448
+
if (acpi_processor_registered == 0)
1449
+
cpuidle_unregister_driver(&acpi_idle_driver);
1450
+
1424
1451
kfree(dev);
1425
1452
}
1426
1453
-2
include/acpi/processor.h
-2
include/acpi/processor.h
···
423
423
int acpi_processor_power_exit(struct acpi_processor *pr);
424
424
int acpi_processor_power_state_has_changed(struct acpi_processor *pr);
425
425
int acpi_processor_hotplug(struct acpi_processor *pr);
426
-
void acpi_processor_register_idle_driver(void);
427
-
void acpi_processor_unregister_idle_driver(void);
428
426
#else
429
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static inline int acpi_processor_power_init(struct acpi_processor *pr)
430
428
{