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1/*
2 * Copyright (C) 2005 Intel Corporation
3 * Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
4 * - Added _PDC for SMP C-states on Intel CPUs
5 */
6
7#include <linux/kernel.h>
8#include <linux/module.h>
9#include <linux/init.h>
10#include <linux/acpi.h>
11#include <linux/cpu.h>
12#include <linux/sched.h>
13
14#include <acpi/processor.h>
15#include <asm/acpi.h>
16#include <asm/mwait.h>
17#include <asm/special_insns.h>
18
19/*
20 * Initialize bm_flags based on the CPU cache properties
21 * On SMP it depends on cache configuration
22 * - When cache is not shared among all CPUs, we flush cache
23 * before entering C3.
24 * - When cache is shared among all CPUs, we use bm_check
25 * mechanism as in UP case
26 *
27 * This routine is called only after all the CPUs are online
28 */
29void acpi_processor_power_init_bm_check(struct acpi_processor_flags *flags,
30 unsigned int cpu)
31{
32 struct cpuinfo_x86 *c = &cpu_data(cpu);
33
34 flags->bm_check = 0;
35 if (num_online_cpus() == 1)
36 flags->bm_check = 1;
37 else if (c->x86_vendor == X86_VENDOR_INTEL) {
38 /*
39 * Today all MP CPUs that support C3 share cache.
40 * And caches should not be flushed by software while
41 * entering C3 type state.
42 */
43 flags->bm_check = 1;
44 }
45
46 /*
47 * On all recent Intel platforms, ARB_DISABLE is a nop.
48 * So, set bm_control to zero to indicate that ARB_DISABLE
49 * is not required while entering C3 type state on
50 * P4, Core and beyond CPUs
51 */
52 if (c->x86_vendor == X86_VENDOR_INTEL &&
53 (c->x86 > 0xf || (c->x86 == 6 && c->x86_model >= 0x0f)))
54 flags->bm_control = 0;
55}
56EXPORT_SYMBOL(acpi_processor_power_init_bm_check);
57
58/* The code below handles cstate entry with monitor-mwait pair on Intel*/
59
60struct cstate_entry {
61 struct {
62 unsigned int eax;
63 unsigned int ecx;
64 } states[ACPI_PROCESSOR_MAX_POWER];
65};
66static struct cstate_entry __percpu *cpu_cstate_entry; /* per CPU ptr */
67
68static short mwait_supported[ACPI_PROCESSOR_MAX_POWER];
69
70#define NATIVE_CSTATE_BEYOND_HALT (2)
71
72static long acpi_processor_ffh_cstate_probe_cpu(void *_cx)
73{
74 struct acpi_processor_cx *cx = _cx;
75 long retval;
76 unsigned int eax, ebx, ecx, edx;
77 unsigned int edx_part;
78 unsigned int cstate_type; /* C-state type and not ACPI C-state type */
79 unsigned int num_cstate_subtype;
80
81 cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
82
83 /* Check whether this particular cx_type (in CST) is supported or not */
84 cstate_type = ((cx->address >> MWAIT_SUBSTATE_SIZE) &
85 MWAIT_CSTATE_MASK) + 1;
86 edx_part = edx >> (cstate_type * MWAIT_SUBSTATE_SIZE);
87 num_cstate_subtype = edx_part & MWAIT_SUBSTATE_MASK;
88
89 retval = 0;
90 if (num_cstate_subtype < (cx->address & MWAIT_SUBSTATE_MASK)) {
91 retval = -1;
92 goto out;
93 }
94
95 /* mwait ecx extensions INTERRUPT_BREAK should be supported for C2/C3 */
96 if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
97 !(ecx & CPUID5_ECX_INTERRUPT_BREAK)) {
98 retval = -1;
99 goto out;
100 }
101
102 if (!mwait_supported[cstate_type]) {
103 mwait_supported[cstate_type] = 1;
104 printk(KERN_DEBUG
105 "Monitor-Mwait will be used to enter C-%d "
106 "state\n", cx->type);
107 }
108 snprintf(cx->desc,
109 ACPI_CX_DESC_LEN, "ACPI FFH INTEL MWAIT 0x%x",
110 cx->address);
111out:
112 return retval;
113}
114
115int acpi_processor_ffh_cstate_probe(unsigned int cpu,
116 struct acpi_processor_cx *cx, struct acpi_power_register *reg)
117{
118 struct cstate_entry *percpu_entry;
119 struct cpuinfo_x86 *c = &cpu_data(cpu);
120 long retval;
121
122 if (!cpu_cstate_entry || c->cpuid_level < CPUID_MWAIT_LEAF)
123 return -1;
124
125 if (reg->bit_offset != NATIVE_CSTATE_BEYOND_HALT)
126 return -1;
127
128 percpu_entry = per_cpu_ptr(cpu_cstate_entry, cpu);
129 percpu_entry->states[cx->index].eax = 0;
130 percpu_entry->states[cx->index].ecx = 0;
131
132 /* Make sure we are running on right CPU */
133
134 retval = work_on_cpu(cpu, acpi_processor_ffh_cstate_probe_cpu, cx);
135 if (retval == 0) {
136 /* Use the hint in CST */
137 percpu_entry->states[cx->index].eax = cx->address;
138 percpu_entry->states[cx->index].ecx = MWAIT_ECX_INTERRUPT_BREAK;
139 }
140
141 /*
142 * For _CST FFH on Intel, if GAS.access_size bit 1 is cleared,
143 * then we should skip checking BM_STS for this C-state.
144 * ref: "Intel Processor Vendor-Specific ACPI Interface Specification"
145 */
146 if ((c->x86_vendor == X86_VENDOR_INTEL) && !(reg->access_size & 0x2))
147 cx->bm_sts_skip = 1;
148
149 return retval;
150}
151EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_probe);
152
153/*
154 * This uses new MONITOR/MWAIT instructions on P4 processors with PNI,
155 * which can obviate IPI to trigger checking of need_resched.
156 * We execute MONITOR against need_resched and enter optimized wait state
157 * through MWAIT. Whenever someone changes need_resched, we would be woken
158 * up from MWAIT (without an IPI).
159 *
160 * New with Core Duo processors, MWAIT can take some hints based on CPU
161 * capability.
162 */
163void mwait_idle_with_hints(unsigned long ax, unsigned long cx)
164{
165 if (!need_resched()) {
166 if (this_cpu_has(X86_FEATURE_CLFLUSH_MONITOR))
167 clflush((void *)¤t_thread_info()->flags);
168
169 __monitor((void *)¤t_thread_info()->flags, 0, 0);
170 smp_mb();
171 if (!need_resched())
172 __mwait(ax, cx);
173 }
174}
175
176void acpi_processor_ffh_cstate_enter(struct acpi_processor_cx *cx)
177{
178 unsigned int cpu = smp_processor_id();
179 struct cstate_entry *percpu_entry;
180
181 percpu_entry = per_cpu_ptr(cpu_cstate_entry, cpu);
182 mwait_idle_with_hints(percpu_entry->states[cx->index].eax,
183 percpu_entry->states[cx->index].ecx);
184}
185EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_enter);
186
187static int __init ffh_cstate_init(void)
188{
189 struct cpuinfo_x86 *c = &boot_cpu_data;
190 if (c->x86_vendor != X86_VENDOR_INTEL)
191 return -1;
192
193 cpu_cstate_entry = alloc_percpu(struct cstate_entry);
194 return 0;
195}
196
197static void __exit ffh_cstate_exit(void)
198{
199 free_percpu(cpu_cstate_entry);
200 cpu_cstate_entry = NULL;
201}
202
203arch_initcall(ffh_cstate_init);
204__exitcall(ffh_cstate_exit);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2005 Intel Corporation
4 * Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
5 * - Added _PDC for SMP C-states on Intel CPUs
6 */
7
8#include <linux/kernel.h>
9#include <linux/export.h>
10#include <linux/init.h>
11#include <linux/acpi.h>
12#include <linux/cpu.h>
13#include <linux/sched.h>
14
15#include <acpi/processor.h>
16#include <asm/mwait.h>
17#include <asm/special_insns.h>
18
19/*
20 * Initialize bm_flags based on the CPU cache properties
21 * On SMP it depends on cache configuration
22 * - When cache is not shared among all CPUs, we flush cache
23 * before entering C3.
24 * - When cache is shared among all CPUs, we use bm_check
25 * mechanism as in UP case
26 *
27 * This routine is called only after all the CPUs are online
28 */
29void acpi_processor_power_init_bm_check(struct acpi_processor_flags *flags,
30 unsigned int cpu)
31{
32 struct cpuinfo_x86 *c = &cpu_data(cpu);
33
34 flags->bm_check = 0;
35 if (num_online_cpus() == 1)
36 flags->bm_check = 1;
37 else if (c->x86_vendor == X86_VENDOR_INTEL) {
38 /*
39 * Today all MP CPUs that support C3 share cache.
40 * And caches should not be flushed by software while
41 * entering C3 type state.
42 */
43 flags->bm_check = 1;
44 }
45
46 /*
47 * On all recent Intel platforms, ARB_DISABLE is a nop.
48 * So, set bm_control to zero to indicate that ARB_DISABLE
49 * is not required while entering C3 type state on
50 * P4, Core and beyond CPUs
51 */
52 if (c->x86_vendor == X86_VENDOR_INTEL &&
53 (c->x86 > 0xf || (c->x86 == 6 && c->x86_model >= 0x0f)))
54 flags->bm_control = 0;
55
56 if (c->x86_vendor == X86_VENDOR_CENTAUR) {
57 if (c->x86 > 6 || (c->x86 == 6 && c->x86_model == 0x0f &&
58 c->x86_stepping >= 0x0e)) {
59 /*
60 * For all recent Centaur CPUs, the ucode will make sure that each
61 * core can keep cache coherence with each other while entering C3
62 * type state. So, set bm_check to 1 to indicate that the kernel
63 * doesn't need to execute a cache flush operation (WBINVD) when
64 * entering C3 type state.
65 */
66 flags->bm_check = 1;
67 /*
68 * For all recent Centaur platforms, ARB_DISABLE is a nop.
69 * Set bm_control to zero to indicate that ARB_DISABLE is
70 * not required while entering C3 type state.
71 */
72 flags->bm_control = 0;
73 }
74 }
75
76 if (c->x86_vendor == X86_VENDOR_ZHAOXIN) {
77 /*
78 * All Zhaoxin CPUs that support C3 share cache.
79 * And caches should not be flushed by software while
80 * entering C3 type state.
81 */
82 flags->bm_check = 1;
83 /*
84 * On all recent Zhaoxin platforms, ARB_DISABLE is a nop.
85 * So, set bm_control to zero to indicate that ARB_DISABLE
86 * is not required while entering C3 type state.
87 */
88 flags->bm_control = 0;
89 }
90 if (c->x86_vendor == X86_VENDOR_AMD && c->x86 >= 0x17) {
91 /*
92 * For all AMD Zen or newer CPUs that support C3, caches
93 * should not be flushed by software while entering C3
94 * type state. Set bm->check to 1 so that kernel doesn't
95 * need to execute cache flush operation.
96 */
97 flags->bm_check = 1;
98 /*
99 * In current AMD C state implementation ARB_DIS is no longer
100 * used. So set bm_control to zero to indicate ARB_DIS is not
101 * required while entering C3 type state.
102 */
103 flags->bm_control = 0;
104 }
105}
106EXPORT_SYMBOL(acpi_processor_power_init_bm_check);
107
108/* The code below handles cstate entry with monitor-mwait pair on Intel*/
109
110struct cstate_entry {
111 struct {
112 unsigned int eax;
113 unsigned int ecx;
114 } states[ACPI_PROCESSOR_MAX_POWER];
115};
116static struct cstate_entry __percpu *cpu_cstate_entry; /* per CPU ptr */
117
118static short mwait_supported[ACPI_PROCESSOR_MAX_POWER];
119
120#define NATIVE_CSTATE_BEYOND_HALT (2)
121
122static long acpi_processor_ffh_cstate_probe_cpu(void *_cx)
123{
124 struct acpi_processor_cx *cx = _cx;
125 long retval;
126 unsigned int eax, ebx, ecx, edx;
127 unsigned int edx_part;
128 unsigned int cstate_type; /* C-state type and not ACPI C-state type */
129 unsigned int num_cstate_subtype;
130
131 cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
132
133 /* Check whether this particular cx_type (in CST) is supported or not */
134 cstate_type = ((cx->address >> MWAIT_SUBSTATE_SIZE) &
135 MWAIT_CSTATE_MASK) + 1;
136 edx_part = edx >> (cstate_type * MWAIT_SUBSTATE_SIZE);
137 num_cstate_subtype = edx_part & MWAIT_SUBSTATE_MASK;
138
139 retval = 0;
140 /* If the HW does not support any sub-states in this C-state */
141 if (num_cstate_subtype == 0) {
142 pr_warn(FW_BUG "ACPI MWAIT C-state 0x%x not supported by HW (0x%x)\n",
143 cx->address, edx_part);
144 retval = -1;
145 goto out;
146 }
147
148 /* mwait ecx extensions INTERRUPT_BREAK should be supported for C2/C3 */
149 if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
150 !(ecx & CPUID5_ECX_INTERRUPT_BREAK)) {
151 retval = -1;
152 goto out;
153 }
154
155 if (!mwait_supported[cstate_type]) {
156 mwait_supported[cstate_type] = 1;
157 printk(KERN_DEBUG
158 "Monitor-Mwait will be used to enter C-%d state\n",
159 cx->type);
160 }
161 snprintf(cx->desc,
162 ACPI_CX_DESC_LEN, "ACPI FFH MWAIT 0x%x",
163 cx->address);
164out:
165 return retval;
166}
167
168int acpi_processor_ffh_cstate_probe(unsigned int cpu,
169 struct acpi_processor_cx *cx, struct acpi_power_register *reg)
170{
171 struct cstate_entry *percpu_entry;
172 struct cpuinfo_x86 *c = &cpu_data(cpu);
173 long retval;
174
175 if (!cpu_cstate_entry || c->cpuid_level < CPUID_MWAIT_LEAF)
176 return -1;
177
178 if (reg->bit_offset != NATIVE_CSTATE_BEYOND_HALT)
179 return -1;
180
181 percpu_entry = per_cpu_ptr(cpu_cstate_entry, cpu);
182 percpu_entry->states[cx->index].eax = 0;
183 percpu_entry->states[cx->index].ecx = 0;
184
185 /* Make sure we are running on right CPU */
186
187 retval = call_on_cpu(cpu, acpi_processor_ffh_cstate_probe_cpu, cx,
188 false);
189 if (retval == 0) {
190 /* Use the hint in CST */
191 percpu_entry->states[cx->index].eax = cx->address;
192 percpu_entry->states[cx->index].ecx = MWAIT_ECX_INTERRUPT_BREAK;
193 }
194
195 /*
196 * For _CST FFH on Intel, if GAS.access_size bit 1 is cleared,
197 * then we should skip checking BM_STS for this C-state.
198 * ref: "Intel Processor Vendor-Specific ACPI Interface Specification"
199 */
200 if ((c->x86_vendor == X86_VENDOR_INTEL) && !(reg->access_size & 0x2))
201 cx->bm_sts_skip = 1;
202
203 return retval;
204}
205EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_probe);
206
207void __cpuidle acpi_processor_ffh_cstate_enter(struct acpi_processor_cx *cx)
208{
209 unsigned int cpu = smp_processor_id();
210 struct cstate_entry *percpu_entry;
211
212 percpu_entry = per_cpu_ptr(cpu_cstate_entry, cpu);
213 mwait_idle_with_hints(percpu_entry->states[cx->index].eax,
214 percpu_entry->states[cx->index].ecx);
215}
216EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_enter);
217
218static int __init ffh_cstate_init(void)
219{
220 struct cpuinfo_x86 *c = &boot_cpu_data;
221
222 if (c->x86_vendor != X86_VENDOR_INTEL &&
223 c->x86_vendor != X86_VENDOR_AMD &&
224 c->x86_vendor != X86_VENDOR_HYGON)
225 return -1;
226
227 cpu_cstate_entry = alloc_percpu(struct cstate_entry);
228 return 0;
229}
230
231static void __exit ffh_cstate_exit(void)
232{
233 free_percpu(cpu_cstate_entry);
234 cpu_cstate_entry = NULL;
235}
236
237arch_initcall(ffh_cstate_init);
238__exitcall(ffh_cstate_exit);