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 */
56 #include <asm/intel-family.h>
58 #include <asm/spec-ctrl.h>
69 static int max_cstate = CPUIDLE_STATE_MAX - 1;
89 	 * Hardware C-state auto-demotion may not always be optimal.
104  * Enable interrupts before entering the C-state. On some platforms and for
105  * some C-states, this may measurably decrease interrupt latency.
121  * Initialize large xstate for the C6-state entrance.
126  * Ignore the sub-state when matching mwait hints between the ACPI _CST and
132  * MWAIT takes an 8-bit "hint" in EAX "suggesting"
133  * the C-state (top nibble) and sub-state (bottom nibble)
145 	struct cpuidle_state *state = &drv->states[index];  in __intel_idle()
146 	unsigned long eax = flg2MWAIT(state->flags);  in __intel_idle()
147 	unsigned long ecx = 1*irqoff; /* break on interrupt flag */  in __intel_idle()  local
149 	mwait_idle_with_hints(eax, ecx);  in __intel_idle()
155  * intel_idle - Ask the processor to enter the given idle state.
164  * enable one-shot tick broadcasting for the target CPU before executing MWAIT.
206  * intel_idle_s2idle - Ask the processor to enter the given idle state.
214  * Invoked as a suspend-to-idle callback routine with frozen user space, frozen
220 	unsigned long ecx = 1; /* break on interrupt flag */  in intel_idle_s2idle()  local
221 	struct cpuidle_state *state = &drv->states[index];  in intel_idle_s2idle()
222 	unsigned long eax = flg2MWAIT(state->flags);  in intel_idle_s2idle()
224 	if (state->flags & CPUIDLE_FLAG_INIT_XSTATE)  in intel_idle_s2idle()
227 	mwait_idle_with_hints(eax, ecx);  in intel_idle_s2idle()
1067 		.target_residency = 1000,
1273 		.exit_latency = 1000,
1274 		.target_residency = 1000,
1676 	unsigned long eax = flg2MWAIT(state->flags);  in intel_idle_state_needs_timer_stop()
1682 	 * Switch over to one-shot tick broadcast if the target C-state  in intel_idle_state_needs_timer_stop()
1702  * intel_idle_cst_usable - Check if the _CST information can be used.
1704  * Check if all of the C-states listed by _CST in the max_cstate range are
1717 		if (cx->entry_method != ACPI_CSTATE_FFH)  in intel_idle_cst_usable()
1739 		if (acpi_processor_evaluate_cst(pr->handle, cpu, &acpi_state_table))  in intel_idle_acpi_cst_extract()
1770 		if (intel_idle_max_cstate_reached(cstate - 1))  in intel_idle_init_cstates_acpi()
1775 		state = &drv->states[drv->state_count++];  in intel_idle_init_cstates_acpi()
1777 		snprintf(state->name, CPUIDLE_NAME_LEN, "C%d_ACPI", cstate);  in intel_idle_init_cstates_acpi()
1778 		strscpy(state->desc, cx->desc, CPUIDLE_DESC_LEN);  in intel_idle_init_cstates_acpi()
1779 		state->exit_latency = cx->latency;  in intel_idle_init_cstates_acpi()
1781 		 * For C1-type C-states use the same number for both the exit  in intel_idle_init_cstates_acpi()
1783 		 * C1 in the majority of the static C-states tables above.  in intel_idle_init_cstates_acpi()
1784 		 * For the other types of C-states, however, set the target  in intel_idle_init_cstates_acpi()
1786 		 * a reasonable balance between energy-efficiency and  in intel_idle_init_cstates_acpi()
1789 		state->target_residency = cx->latency;  in intel_idle_init_cstates_acpi()
1790 		if (cx->type > ACPI_STATE_C1)  in intel_idle_init_cstates_acpi()
1791 			state->target_residency *= 3;  in intel_idle_init_cstates_acpi()
1793 		state->flags = MWAIT2flg(cx->address);  in intel_idle_init_cstates_acpi()
1794 		if (cx->type > ACPI_STATE_C2)  in intel_idle_init_cstates_acpi()
1795 			state->flags |= CPUIDLE_FLAG_TLB_FLUSHED;  in intel_idle_init_cstates_acpi()
1798 			state->flags |= CPUIDLE_FLAG_OFF;  in intel_idle_init_cstates_acpi()
1801 			state->flags |= CPUIDLE_FLAG_TIMER_STOP;  in intel_idle_init_cstates_acpi()
1803 		if (cx->type > ACPI_STATE_C1 && !boot_cpu_has(X86_FEATURE_NONSTOP_TSC))  in intel_idle_init_cstates_acpi()
1806 		state->enter = intel_idle;  in intel_idle_init_cstates_acpi()
1807 		state->enter_s2idle = intel_idle_s2idle;  in intel_idle_init_cstates_acpi()
1816 	 * If there are no _CST C-states, do not disable any C-states by  in intel_idle_off_by_default()
1853  * ivt_idle_state_table_update - Tune the idle states table for Ivy Town.
1855  * Tune IVT multi-socket targets.
1860 	/* IVT uses a different table for 1-2, 3-4, and > 4 sockets */  in ivt_idle_state_table_update()
1882  * irtl_2_usec - IRTL to microseconds conversion.
1903  * bxt_idle_state_table_update - Fix up the Broxton idle states table.
1951  * sklh_idle_state_table_update - Fix up the Sky Lake idle states table.
1953  * On SKL-H (model 0x5e) skip C8 and C9 if C10 is enabled and SGX disabled.
1958 	unsigned int eax, ebx, ecx, edx;  in sklh_idle_state_table_update()  local
1971 	/* PC10 is not enabled in PKG C-state limit */  in sklh_idle_state_table_update()
1975 	ecx = 0;  in sklh_idle_state_table_update()
1976 	cpuid(7, &eax, &ebx, &ecx, &edx);  in sklh_idle_state_table_update()
1988 	skl_cstates[5].flags |= CPUIDLE_FLAG_UNUSABLE;	/* C8-SKL */  in sklh_idle_state_table_update()
1989 	skl_cstates[6].flags |= CPUIDLE_FLAG_UNUSABLE;	/* C9-SKL */  in sklh_idle_state_table_update()
1993  * skx_idle_state_table_update - Adjust the Sky Lake/Cascade Lake
2003 	 * 000b: C0/C1 (no package C-state support)  in skx_idle_state_table_update()
2005 	 * 010b: C6 (non-retention)  in skx_idle_state_table_update()
2023  * adl_idle_state_table_update - Adjust AlderLake idle states table.
2042  * spr_idle_state_table_update - Adjust Sapphire Rapids idle states table.
2049 	 * By default, the C6 state assumes the worst-case scenario of package  in spr_idle_state_table_update()
2069 	/* Ignore the C-state if there are NO sub-states in CPUID for it. */  in intel_idle_verify_cstate()
2081 	if (state->flags & CPUIDLE_FLAG_INIT_XSTATE) {  in state_update_enter_method()
2086 		WARN_ON_ONCE(state->flags & CPUIDLE_FLAG_IBRS);  in state_update_enter_method()
2087 		WARN_ON_ONCE(state->flags & CPUIDLE_FLAG_IRQ_ENABLE);  in state_update_enter_method()
2088 		state->enter = intel_idle_xstate;  in state_update_enter_method()
2093 			((state->flags & CPUIDLE_FLAG_IBRS) || ibrs_off)) {  in state_update_enter_method()
2095 		 * IBRS mitigation requires that C-states are entered  in state_update_enter_method()
2098 		if (ibrs_off && (state->flags & CPUIDLE_FLAG_IRQ_ENABLE))  in state_update_enter_method()
2099 			state->flags &= ~CPUIDLE_FLAG_IRQ_ENABLE;  in state_update_enter_method()
2100 		WARN_ON_ONCE(state->flags & CPUIDLE_FLAG_IRQ_ENABLE);  in state_update_enter_method()
2101 		state->enter = intel_idle_ibrs;  in state_update_enter_method()
2105 	if (state->flags & CPUIDLE_FLAG_IRQ_ENABLE) {  in state_update_enter_method()
2106 		state->enter = intel_idle_irq;  in state_update_enter_method()
2112 		state->enter = intel_idle_irq;  in state_update_enter_method()
2168 		drv->states[drv->state_count] = cpuidle_state_table[cstate];  in intel_idle_init_cstates_icpu()
2169 		state = &drv->states[drv->state_count];  in intel_idle_init_cstates_icpu()
2174 		if ((disabled_states_mask & BIT(drv->state_count)) ||  in intel_idle_init_cstates_icpu()
2175 		    ((icpu->use_acpi || force_use_acpi) &&  in intel_idle_init_cstates_icpu()
2176 		     intel_idle_off_by_default(state->flags, mwait_hint) &&  in intel_idle_init_cstates_icpu()
2177 		     !(state->flags & CPUIDLE_FLAG_ALWAYS_ENABLE)))  in intel_idle_init_cstates_icpu()
2178 			state->flags |= CPUIDLE_FLAG_OFF;  in intel_idle_init_cstates_icpu()
2181 			state->flags |= CPUIDLE_FLAG_TIMER_STOP;  in intel_idle_init_cstates_icpu()
2183 		drv->state_count++;  in intel_idle_init_cstates_icpu()
2186 	if (icpu->byt_auto_demotion_disable_flag) {  in intel_idle_init_cstates_icpu()
2193  * intel_idle_cpuidle_driver_init - Create the list of available idle states.
2201 		drv->states[0].flags |= CPUIDLE_FLAG_OFF;  in intel_idle_cpuidle_driver_init()
2203 	drv->state_count = 1;  in intel_idle_cpuidle_driver_init()
2205 	if (icpu && icpu->state_table)  in intel_idle_cpuidle_driver_init()
2239  * intel_idle_cpu_init - Register the target CPU with the cpuidle core.
2250 	dev->cpu = cpu;  in intel_idle_cpu_init()
2254 		return -EIO;  in intel_idle_cpu_init()
2281 	if (!dev->registered)  in intel_idle_cpu_online()
2288  * intel_idle_cpuidle_devices_uninit - Unregister all cpuidle devices.
2301 	unsigned int eax, ebx, ecx;  in intel_idle_init()  local
2306 		return -ENODEV;  in intel_idle_init()
2310 		return -EPERM;  in intel_idle_init()
2317 			return -ENODEV;  in intel_idle_init()
2322 			return -ENODEV;  in intel_idle_init()
2325 	cpuid(CPUID_LEAF_MWAIT, &eax, &ebx, &ecx, &mwait_substates);  in intel_idle_init()
2327 	if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||  in intel_idle_init()
2328 	    !(ecx & CPUID5_ECX_INTERRUPT_BREAK) ||  in intel_idle_init()
2330 			return -ENODEV;  in intel_idle_init()
2334 	icpu = (const struct idle_cpu *)id->driver_data;  in intel_idle_init()
2336 		if (icpu->state_table)  in intel_idle_init()
2337 			cpuidle_state_table = icpu->state_table;  in intel_idle_init()
2339 			return -ENODEV;  in intel_idle_init()
2341 		auto_demotion_disable_flags = icpu->auto_demotion_disable_flags;  in intel_idle_init()
2342 		if (icpu->disable_promotion_to_c1e)  in intel_idle_init()
2344 		if (icpu->use_acpi || force_use_acpi)  in intel_idle_init()
2347 		return -ENODEV;  in intel_idle_init()
2355 		return -ENOMEM;  in intel_idle_init()
2363 		       drv ? drv->name : "none");  in intel_idle_init()
2373 		 boot_cpu_has(X86_FEATURE_ARAT) ? "all C-states" : "C1");  in intel_idle_init()
2389  * support "intel_idle.max_cstate=..." at boot and also a read-only export of
2390  * it at /sys/module/intel_idle/parameters/max_cstate -- so using module_param
2403  * Some platforms come with mutually exclusive C-states, so that if one is
2404  * enabled, the other C-states must not be used. Example: C1 and C1E on
2406  * preferred C-states among the groups of mutually exclusive C-states - the
2407  * selected C-states will be registered, the other C-states from the mutually
2409  * exclusive C-states, this parameter has no effect.
2414  * Debugging option that forces the driver to enter all C-states with
2415  * interrupts enabled. Does not apply to C-states with