Commit | Line | Data |
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61c4628b SS |
1 | #include <linux/errno.h> |
2 | #include <linux/kernel.h> | |
3 | #include <linux/mm.h> | |
4 | #include <linux/smp.h> | |
5 | #include <linux/slab.h> | |
6 | #include <linux/sched.h> | |
7f424a8b PZ |
7 | #include <linux/module.h> |
8 | #include <linux/pm.h> | |
61c4628b | 9 | |
aa283f49 | 10 | struct kmem_cache *task_xstate_cachep; |
61c4628b SS |
11 | |
12 | int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) | |
13 | { | |
14 | *dst = *src; | |
aa283f49 SS |
15 | if (src->thread.xstate) { |
16 | dst->thread.xstate = kmem_cache_alloc(task_xstate_cachep, | |
17 | GFP_KERNEL); | |
18 | if (!dst->thread.xstate) | |
19 | return -ENOMEM; | |
20 | WARN_ON((unsigned long)dst->thread.xstate & 15); | |
21 | memcpy(dst->thread.xstate, src->thread.xstate, xstate_size); | |
22 | } | |
61c4628b SS |
23 | return 0; |
24 | } | |
25 | ||
aa283f49 | 26 | void free_thread_xstate(struct task_struct *tsk) |
61c4628b | 27 | { |
aa283f49 SS |
28 | if (tsk->thread.xstate) { |
29 | kmem_cache_free(task_xstate_cachep, tsk->thread.xstate); | |
30 | tsk->thread.xstate = NULL; | |
31 | } | |
32 | } | |
33 | ||
aa283f49 SS |
34 | void free_thread_info(struct thread_info *ti) |
35 | { | |
36 | free_thread_xstate(ti->task); | |
1679f271 | 37 | free_pages((unsigned long)ti, get_order(THREAD_SIZE)); |
61c4628b SS |
38 | } |
39 | ||
40 | void arch_task_cache_init(void) | |
41 | { | |
42 | task_xstate_cachep = | |
43 | kmem_cache_create("task_xstate", xstate_size, | |
44 | __alignof__(union thread_xstate), | |
45 | SLAB_PANIC, NULL); | |
46 | } | |
7f424a8b | 47 | |
00dba564 TG |
48 | /* |
49 | * Idle related variables and functions | |
50 | */ | |
51 | unsigned long boot_option_idle_override = 0; | |
52 | EXPORT_SYMBOL(boot_option_idle_override); | |
53 | ||
54 | /* | |
55 | * Powermanagement idle function, if any.. | |
56 | */ | |
57 | void (*pm_idle)(void); | |
58 | EXPORT_SYMBOL(pm_idle); | |
59 | ||
60 | #ifdef CONFIG_X86_32 | |
61 | /* | |
62 | * This halt magic was a workaround for ancient floppy DMA | |
63 | * wreckage. It should be safe to remove. | |
64 | */ | |
65 | static int hlt_counter; | |
66 | void disable_hlt(void) | |
67 | { | |
68 | hlt_counter++; | |
69 | } | |
70 | EXPORT_SYMBOL(disable_hlt); | |
71 | ||
72 | void enable_hlt(void) | |
73 | { | |
74 | hlt_counter--; | |
75 | } | |
76 | EXPORT_SYMBOL(enable_hlt); | |
77 | ||
78 | static inline int hlt_use_halt(void) | |
79 | { | |
80 | return (!hlt_counter && boot_cpu_data.hlt_works_ok); | |
81 | } | |
82 | #else | |
83 | static inline int hlt_use_halt(void) | |
84 | { | |
85 | return 1; | |
86 | } | |
87 | #endif | |
88 | ||
89 | /* | |
90 | * We use this if we don't have any better | |
91 | * idle routine.. | |
92 | */ | |
93 | void default_idle(void) | |
94 | { | |
95 | if (hlt_use_halt()) { | |
96 | current_thread_info()->status &= ~TS_POLLING; | |
97 | /* | |
98 | * TS_POLLING-cleared state must be visible before we | |
99 | * test NEED_RESCHED: | |
100 | */ | |
101 | smp_mb(); | |
102 | ||
103 | if (!need_resched()) | |
104 | safe_halt(); /* enables interrupts racelessly */ | |
105 | else | |
106 | local_irq_enable(); | |
107 | current_thread_info()->status |= TS_POLLING; | |
108 | } else { | |
109 | local_irq_enable(); | |
110 | /* loop is done by the caller */ | |
111 | cpu_relax(); | |
112 | } | |
113 | } | |
114 | #ifdef CONFIG_APM_MODULE | |
115 | EXPORT_SYMBOL(default_idle); | |
116 | #endif | |
117 | ||
7f424a8b PZ |
118 | static void do_nothing(void *unused) |
119 | { | |
120 | } | |
121 | ||
122 | /* | |
123 | * cpu_idle_wait - Used to ensure that all the CPUs discard old value of | |
124 | * pm_idle and update to new pm_idle value. Required while changing pm_idle | |
125 | * handler on SMP systems. | |
126 | * | |
127 | * Caller must have changed pm_idle to the new value before the call. Old | |
128 | * pm_idle value will not be used by any CPU after the return of this function. | |
129 | */ | |
130 | void cpu_idle_wait(void) | |
131 | { | |
132 | smp_mb(); | |
133 | /* kick all the CPUs so that they exit out of pm_idle */ | |
134 | smp_call_function(do_nothing, NULL, 0, 1); | |
135 | } | |
136 | EXPORT_SYMBOL_GPL(cpu_idle_wait); | |
137 | ||
138 | /* | |
139 | * This uses new MONITOR/MWAIT instructions on P4 processors with PNI, | |
140 | * which can obviate IPI to trigger checking of need_resched. | |
141 | * We execute MONITOR against need_resched and enter optimized wait state | |
142 | * through MWAIT. Whenever someone changes need_resched, we would be woken | |
143 | * up from MWAIT (without an IPI). | |
144 | * | |
145 | * New with Core Duo processors, MWAIT can take some hints based on CPU | |
146 | * capability. | |
147 | */ | |
148 | void mwait_idle_with_hints(unsigned long ax, unsigned long cx) | |
149 | { | |
150 | if (!need_resched()) { | |
151 | __monitor((void *)¤t_thread_info()->flags, 0, 0); | |
152 | smp_mb(); | |
153 | if (!need_resched()) | |
154 | __mwait(ax, cx); | |
155 | } | |
156 | } | |
157 | ||
158 | /* Default MONITOR/MWAIT with no hints, used for default C1 state */ | |
159 | static void mwait_idle(void) | |
160 | { | |
161 | if (!need_resched()) { | |
162 | __monitor((void *)¤t_thread_info()->flags, 0, 0); | |
163 | smp_mb(); | |
164 | if (!need_resched()) | |
165 | __sti_mwait(0, 0); | |
166 | else | |
167 | local_irq_enable(); | |
168 | } else | |
169 | local_irq_enable(); | |
170 | } | |
171 | ||
7f424a8b PZ |
172 | /* |
173 | * On SMP it's slightly faster (but much more power-consuming!) | |
174 | * to poll the ->work.need_resched flag instead of waiting for the | |
175 | * cross-CPU IPI to arrive. Use this option with caution. | |
176 | */ | |
177 | static void poll_idle(void) | |
178 | { | |
179 | local_irq_enable(); | |
180 | cpu_relax(); | |
181 | } | |
182 | ||
e9623b35 TG |
183 | /* |
184 | * mwait selection logic: | |
185 | * | |
186 | * It depends on the CPU. For AMD CPUs that support MWAIT this is | |
187 | * wrong. Family 0x10 and 0x11 CPUs will enter C1 on HLT. Powersavings | |
188 | * then depend on a clock divisor and current Pstate of the core. If | |
189 | * all cores of a processor are in halt state (C1) the processor can | |
190 | * enter the C1E (C1 enhanced) state. If mwait is used this will never | |
191 | * happen. | |
192 | * | |
193 | * idle=mwait overrides this decision and forces the usage of mwait. | |
194 | */ | |
09fd4b4e TG |
195 | |
196 | #define MWAIT_INFO 0x05 | |
197 | #define MWAIT_ECX_EXTENDED_INFO 0x01 | |
198 | #define MWAIT_EDX_C1 0xf0 | |
199 | ||
e9623b35 TG |
200 | static int __cpuinit mwait_usable(const struct cpuinfo_x86 *c) |
201 | { | |
09fd4b4e TG |
202 | u32 eax, ebx, ecx, edx; |
203 | ||
e9623b35 TG |
204 | if (force_mwait) |
205 | return 1; | |
206 | ||
09fd4b4e TG |
207 | if (c->cpuid_level < MWAIT_INFO) |
208 | return 0; | |
209 | ||
210 | cpuid(MWAIT_INFO, &eax, &ebx, &ecx, &edx); | |
211 | /* Check, whether EDX has extended info about MWAIT */ | |
212 | if (!(ecx & MWAIT_ECX_EXTENDED_INFO)) | |
213 | return 1; | |
214 | ||
215 | /* | |
216 | * edx enumeratios MONITOR/MWAIT extensions. Check, whether | |
217 | * C1 supports MWAIT | |
218 | */ | |
219 | return (edx & MWAIT_EDX_C1); | |
e9623b35 TG |
220 | } |
221 | ||
7f424a8b PZ |
222 | void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c) |
223 | { | |
7f424a8b PZ |
224 | #ifdef CONFIG_X86_SMP |
225 | if (pm_idle == poll_idle && smp_num_siblings > 1) { | |
226 | printk(KERN_WARNING "WARNING: polling idle and HT enabled," | |
227 | " performance may degrade.\n"); | |
228 | } | |
229 | #endif | |
6ddd2a27 TG |
230 | if (pm_idle) |
231 | return; | |
232 | ||
e9623b35 | 233 | if (cpu_has(c, X86_FEATURE_MWAIT) && mwait_usable(c)) { |
7f424a8b | 234 | /* |
7f424a8b PZ |
235 | * One CPU supports mwait => All CPUs supports mwait |
236 | */ | |
6ddd2a27 TG |
237 | printk(KERN_INFO "using mwait in idle threads.\n"); |
238 | pm_idle = mwait_idle; | |
239 | } else | |
240 | pm_idle = default_idle; | |
7f424a8b PZ |
241 | } |
242 | ||
243 | static int __init idle_setup(char *str) | |
244 | { | |
245 | if (!strcmp(str, "poll")) { | |
246 | printk("using polling idle threads.\n"); | |
247 | pm_idle = poll_idle; | |
248 | } else if (!strcmp(str, "mwait")) | |
249 | force_mwait = 1; | |
250 | else | |
251 | return -1; | |
252 | ||
253 | boot_option_idle_override = 1; | |
254 | return 0; | |
255 | } | |
256 | early_param("idle", idle_setup); | |
257 |