1 // SPDX-License-Identifier: GPL-2.0-only
3  * intel_idle.c - native hardware idle loop for modern Intel processors
5  * Copyright (c) 2013 - 2020, Intel Corporation.
23  *	for preventing entry into deep C-states
25  * CPU will flush caches as needed when entering a C-state via MWAIT
33  * ACPI has a .suspend hack to turn off deep c-statees during suspend
39 /* un-comment DEBUG to enable pr_debug() statements */
55 #include <asm/intel-family.h>
56 #include <asm/nospec-branch.h>
67 static int max_cstate = CPUIDLE_STATE_MAX - 1;
79 	 * Hardware C-state auto-demotion may not always be optimal.
105  * MWAIT takes an 8-bit "hint" in EAX "suggesting"
106  * the C-state (top nibble) and sub-state (bottom nibble)
115  * intel_idle - Ask the processor to enter the given idle state.
124  * enable one-shot tick broadcasting for the target CPU before executing MWAIT.
134 	struct cpuidle_state *state = &drv->states[index];  in intel_idle()
135 	unsigned long eax = flg2MWAIT(state->flags);  in intel_idle()
136 	unsigned long ecx = 1; /* break on interrupt flag */  in intel_idle()  local
138 	mwait_idle_with_hints(eax, ecx);  in intel_idle()
162  * intel_idle_s2idle - Ask the processor to enter the given idle state.
170  * Invoked as a suspend-to-idle callback routine with frozen user space, frozen
176 	unsigned long eax = flg2MWAIT(drv->states[index].flags);  in intel_idle_s2idle()
177 	unsigned long ecx = 1; /* break on interrupt flag */  in intel_idle_s2idle()  local
179 	mwait_idle_with_hints(eax, ecx);  in intel_idle_s2idle()
947 		.exit_latency = 2000,
948 		.target_residency = 2000,
1171 	unsigned long eax = flg2MWAIT(state->flags);  in intel_idle_state_needs_timer_stop()
1177 	 * Switch over to one-shot tick broadcast if the target C-state  in intel_idle_state_needs_timer_stop()
1197  * intel_idle_cst_usable - Check if the _CST information can be used.
1199  * Check if all of the C-states listed by _CST in the max_cstate range are
1212 		if (cx->entry_method != ACPI_CSTATE_FFH)  in intel_idle_cst_usable()
1234 		if (acpi_processor_evaluate_cst(pr->handle, cpu, &acpi_state_table))  in intel_idle_acpi_cst_extract()
1265 		if (intel_idle_max_cstate_reached(cstate - 1))  in intel_idle_init_cstates_acpi()
1270 		state = &drv->states[drv->state_count++];  in intel_idle_init_cstates_acpi()
1272 		snprintf(state->name, CPUIDLE_NAME_LEN, "C%d_ACPI", cstate);  in intel_idle_init_cstates_acpi()
1273 		strlcpy(state->desc, cx->desc, CPUIDLE_DESC_LEN);  in intel_idle_init_cstates_acpi()
1274 		state->exit_latency = cx->latency;  in intel_idle_init_cstates_acpi()
1276 		 * For C1-type C-states use the same number for both the exit  in intel_idle_init_cstates_acpi()
1278 		 * C1 in the majority of the static C-states tables above.  in intel_idle_init_cstates_acpi()
1279 		 * For the other types of C-states, however, set the target  in intel_idle_init_cstates_acpi()
1281 		 * a reasonable balance between energy-efficiency and  in intel_idle_init_cstates_acpi()
1284 		state->target_residency = cx->latency;  in intel_idle_init_cstates_acpi()
1285 		if (cx->type > ACPI_STATE_C1)  in intel_idle_init_cstates_acpi()
1286 			state->target_residency *= 3;  in intel_idle_init_cstates_acpi()
1288 		state->flags = MWAIT2flg(cx->address);  in intel_idle_init_cstates_acpi()
1289 		if (cx->type > ACPI_STATE_C2)  in intel_idle_init_cstates_acpi()
1290 			state->flags |= CPUIDLE_FLAG_TLB_FLUSHED;  in intel_idle_init_cstates_acpi()
1293 			state->flags |= CPUIDLE_FLAG_OFF;  in intel_idle_init_cstates_acpi()
1296 			state->flags |= CPUIDLE_FLAG_TIMER_STOP;  in intel_idle_init_cstates_acpi()
1298 		state->enter = intel_idle;  in intel_idle_init_cstates_acpi()
1299 		state->enter_s2idle = intel_idle_s2idle;  in intel_idle_init_cstates_acpi()
1308 	 * If there are no _CST C-states, do not disable any C-states by  in intel_idle_off_by_default()
1334  * ivt_idle_state_table_update - Tune the idle states table for Ivy Town.
1336  * Tune IVT multi-socket targets.
1341 	/* IVT uses a different table for 1-2, 3-4, and > 4 sockets */  in ivt_idle_state_table_update()
1363  * irtl_2_usec - IRTL to microseconds conversion.
1384  * bxt_idle_state_table_update - Fix up the Broxton idle states table.
1432  * sklh_idle_state_table_update - Fix up the Sky Lake idle states table.
1434  * On SKL-H (model 0x5e) skip C8 and C9 if C10 is enabled and SGX disabled.
1439 	unsigned int eax, ebx, ecx, edx;  in sklh_idle_state_table_update()  local
1452 	/* PC10 is not enabled in PKG C-state limit */  in sklh_idle_state_table_update()
1456 	ecx = 0;  in sklh_idle_state_table_update()
1457 	cpuid(7, &eax, &ebx, &ecx, &edx);  in sklh_idle_state_table_update()
1469 	skl_cstates[5].flags |= CPUIDLE_FLAG_UNUSABLE;	/* C8-SKL */  in sklh_idle_state_table_update()
1470 	skl_cstates[6].flags |= CPUIDLE_FLAG_UNUSABLE;	/* C9-SKL */  in sklh_idle_state_table_update()
1479 	/* Ignore the C-state if there are NO sub-states in CPUID for it. */  in intel_idle_verify_cstate()
1528 		drv->states[drv->state_count] = cpuidle_state_table[cstate];  in intel_idle_init_cstates_icpu()
1532 			drv->states[drv->state_count].enter = intel_idle_ibrs;  in intel_idle_init_cstates_icpu()
1535 		if ((disabled_states_mask & BIT(drv->state_count)) ||  in intel_idle_init_cstates_icpu()
1536 		    ((icpu->use_acpi || force_use_acpi) &&  in intel_idle_init_cstates_icpu()
1539 			drv->states[drv->state_count].flags |= CPUIDLE_FLAG_OFF;  in intel_idle_init_cstates_icpu()
1541 		if (intel_idle_state_needs_timer_stop(&drv->states[drv->state_count]))  in intel_idle_init_cstates_icpu()
1542 			drv->states[drv->state_count].flags |= CPUIDLE_FLAG_TIMER_STOP;  in intel_idle_init_cstates_icpu()
1544 		drv->state_count++;  in intel_idle_init_cstates_icpu()
1547 	if (icpu->byt_auto_demotion_disable_flag) {  in intel_idle_init_cstates_icpu()
1554  * intel_idle_cpuidle_driver_init - Create the list of available idle states.
1562 		drv->states[0].flags |= CPUIDLE_FLAG_OFF;  in intel_idle_cpuidle_driver_init()
1564 	drv->state_count = 1;  in intel_idle_cpuidle_driver_init()
1591  * intel_idle_cpu_init - Register the target CPU with the cpuidle core.
1602 	dev->cpu = cpu;  in intel_idle_cpu_init()
1606 		return -EIO;  in intel_idle_cpu_init()
1631 	if (!dev->registered)  in intel_idle_cpu_online()
1638  * intel_idle_cpuidle_devices_uninit - Unregister all cpuidle devices.
1651 	unsigned int eax, ebx, ecx;  in intel_idle_init()  local
1656 		return -ENODEV;  in intel_idle_init()
1660 		return -EPERM;  in intel_idle_init()
1667 			return -ENODEV;  in intel_idle_init()
1672 			return -ENODEV;  in intel_idle_init()
1676 		return -ENODEV;  in intel_idle_init()
1678 	cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &mwait_substates);  in intel_idle_init()
1680 	if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||  in intel_idle_init()
1681 	    !(ecx & CPUID5_ECX_INTERRUPT_BREAK) ||  in intel_idle_init()
1683 			return -ENODEV;  in intel_idle_init()
1687 	icpu = (const struct idle_cpu *)id->driver_data;  in intel_idle_init()
1689 		cpuidle_state_table = icpu->state_table;  in intel_idle_init()
1690 		auto_demotion_disable_flags = icpu->auto_demotion_disable_flags;  in intel_idle_init()
1691 		disable_promotion_to_c1e = icpu->disable_promotion_to_c1e;  in intel_idle_init()
1692 		if (icpu->use_acpi || force_use_acpi)  in intel_idle_init()
1695 		return -ENODEV;  in intel_idle_init()
1703 		return -ENOMEM;  in intel_idle_init()
1711 		       drv ? drv->name : "none");  in intel_idle_init()
1721 		 boot_cpu_has(X86_FEATURE_ARAT) ? "all C-states" : "C1");  in intel_idle_init()
1737  * support "intel_idle.max_cstate=..." at boot and also a read-only export of
1738  * it at /sys/module/intel_idle/parameters/max_cstate -- so using module_param