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
|
/*
* Copyright (C) 2005 Intel Corporation
* Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
* - Added _PDC for SMP C-states on Intel CPUs
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/acpi.h>
#include <linux/cpu.h>
#include <linux/sched.h>
#include <acpi/processor.h>
#include <asm/acpi.h>
#include <asm/mwait.h>
#include <asm/special_insns.h>
/*
* Initialize bm_flags based on the CPU cache properties
* On SMP it depends on cache configuration
* - When cache is not shared among all CPUs, we flush cache
* before entering C3.
* - When cache is shared among all CPUs, we use bm_check
* mechanism as in UP case
*
* This routine is called only after all the CPUs are online
*/
void acpi_processor_power_init_bm_check(struct acpi_processor_flags *flags,
unsigned int cpu)
{
struct cpuinfo_x86 *c = &cpu_data(cpu);
flags->bm_check = 0;
if (num_online_cpus() == 1)
flags->bm_check = 1;
else if (c->x86_vendor == X86_VENDOR_INTEL) {
/*
* Today all MP CPUs that support C3 share cache.
* And caches should not be flushed by software while
* entering C3 type state.
*/
flags->bm_check = 1;
}
/*
* On all recent Intel platforms, ARB_DISABLE is a nop.
* So, set bm_control to zero to indicate that ARB_DISABLE
* is not required while entering C3 type state on
* P4, Core and beyond CPUs
*/
if (c->x86_vendor == X86_VENDOR_INTEL &&
(c->x86 > 0xf || (c->x86 == 6 && c->x86_model >= 0x0f)))
flags->bm_control = 0;
}
EXPORT_SYMBOL(acpi_processor_power_init_bm_check);
/* The code below handles cstate entry with monitor-mwait pair on Intel*/
struct cstate_entry {
struct {
unsigned int eax;
unsigned int ecx;
} states[ACPI_PROCESSOR_MAX_POWER];
};
static struct cstate_entry __percpu *cpu_cstate_entry; /* per CPU ptr */
static short mwait_supported[ACPI_PROCESSOR_MAX_POWER];
#define NATIVE_CSTATE_BEYOND_HALT (2)
static long acpi_processor_ffh_cstate_probe_cpu(void *_cx)
{
struct acpi_processor_cx *cx = _cx;
long retval;
unsigned int eax, ebx, ecx, edx;
unsigned int edx_part;
unsigned int cstate_type; /* C-state type and not ACPI C-state type */
unsigned int num_cstate_subtype;
cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
/* Check whether this particular cx_type (in CST) is supported or not */
cstate_type = ((cx->address >> MWAIT_SUBSTATE_SIZE) &
MWAIT_CSTATE_MASK) + 1;
edx_part = edx >> (cstate_type * MWAIT_SUBSTATE_SIZE);
num_cstate_subtype = edx_part & MWAIT_SUBSTATE_MASK;
retval = 0;
if (num_cstate_subtype < (cx->address & MWAIT_SUBSTATE_MASK)) {
retval = -1;
goto out;
}
/* mwait ecx extensions INTERRUPT_BREAK should be supported for C2/C3 */
if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
!(ecx & CPUID5_ECX_INTERRUPT_BREAK)) {
retval = -1;
goto out;
}
if (!mwait_supported[cstate_type]) {
mwait_supported[cstate_type] = 1;
printk(KERN_DEBUG
"Monitor-Mwait will be used to enter C-%d "
"state\n", cx->type);
}
snprintf(cx->desc,
ACPI_CX_DESC_LEN, "ACPI FFH INTEL MWAIT 0x%x",
cx->address);
out:
return retval;
}
int acpi_processor_ffh_cstate_probe(unsigned int cpu,
struct acpi_processor_cx *cx, struct acpi_power_register *reg)
{
struct cstate_entry *percpu_entry;
struct cpuinfo_x86 *c = &cpu_data(cpu);
long retval;
if (!cpu_cstate_entry || c->cpuid_level < CPUID_MWAIT_LEAF)
return -1;
if (reg->bit_offset != NATIVE_CSTATE_BEYOND_HALT)
return -1;
percpu_entry = per_cpu_ptr(cpu_cstate_entry, cpu);
percpu_entry->states[cx->index].eax = 0;
percpu_entry->states[cx->index].ecx = 0;
/* Make sure we are running on right CPU */
retval = work_on_cpu(cpu, acpi_processor_ffh_cstate_probe_cpu, cx);
if (retval == 0) {
/* Use the hint in CST */
percpu_entry->states[cx->index].eax = cx->address;
percpu_entry->states[cx->index].ecx = MWAIT_ECX_INTERRUPT_BREAK;
}
/*
* For _CST FFH on Intel, if GAS.access_size bit 1 is cleared,
* then we should skip checking BM_STS for this C-state.
* ref: "Intel Processor Vendor-Specific ACPI Interface Specification"
*/
if ((c->x86_vendor == X86_VENDOR_INTEL) && !(reg->access_size & 0x2))
cx->bm_sts_skip = 1;
return retval;
}
EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_probe);
/*
* This uses new MONITOR/MWAIT instructions on P4 processors with PNI,
* which can obviate IPI to trigger checking of need_resched.
* We execute MONITOR against need_resched and enter optimized wait state
* through MWAIT. Whenever someone changes need_resched, we would be woken
* up from MWAIT (without an IPI).
*
* New with Core Duo processors, MWAIT can take some hints based on CPU
* capability.
*/
void mwait_idle_with_hints(unsigned long ax, unsigned long cx)
{
if (!need_resched()) {
if (this_cpu_has(X86_FEATURE_CLFLUSH_MONITOR))
clflush((void *)¤t_thread_info()->flags);
__monitor((void *)¤t_thread_info()->flags, 0, 0);
smp_mb();
if (!need_resched())
__mwait(ax, cx);
}
}
void acpi_processor_ffh_cstate_enter(struct acpi_processor_cx *cx)
{
unsigned int cpu = smp_processor_id();
struct cstate_entry *percpu_entry;
percpu_entry = per_cpu_ptr(cpu_cstate_entry, cpu);
mwait_idle_with_hints(percpu_entry->states[cx->index].eax,
percpu_entry->states[cx->index].ecx);
}
EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_enter);
static int __init ffh_cstate_init(void)
{
struct cpuinfo_x86 *c = &boot_cpu_data;
if (c->x86_vendor != X86_VENDOR_INTEL)
return -1;
cpu_cstate_entry = alloc_percpu(struct cstate_entry);
return 0;
}
static void __exit ffh_cstate_exit(void)
{
free_percpu(cpu_cstate_entry);
cpu_cstate_entry = NULL;
}
arch_initcall(ffh_cstate_init);
__exitcall(ffh_cstate_exit);
|
