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> | |
aa276e1c | 9 | #include <linux/clockchips.h> |
61c4628b | 10 | |
aa283f49 | 11 | struct kmem_cache *task_xstate_cachep; |
61c4628b SS |
12 | |
13 | int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) | |
14 | { | |
15 | *dst = *src; | |
aa283f49 SS |
16 | if (src->thread.xstate) { |
17 | dst->thread.xstate = kmem_cache_alloc(task_xstate_cachep, | |
18 | GFP_KERNEL); | |
19 | if (!dst->thread.xstate) | |
20 | return -ENOMEM; | |
21 | WARN_ON((unsigned long)dst->thread.xstate & 15); | |
22 | memcpy(dst->thread.xstate, src->thread.xstate, xstate_size); | |
23 | } | |
61c4628b SS |
24 | return 0; |
25 | } | |
26 | ||
aa283f49 | 27 | void free_thread_xstate(struct task_struct *tsk) |
61c4628b | 28 | { |
aa283f49 SS |
29 | if (tsk->thread.xstate) { |
30 | kmem_cache_free(task_xstate_cachep, tsk->thread.xstate); | |
31 | tsk->thread.xstate = NULL; | |
32 | } | |
33 | } | |
34 | ||
aa283f49 SS |
35 | void free_thread_info(struct thread_info *ti) |
36 | { | |
37 | free_thread_xstate(ti->task); | |
1679f271 | 38 | free_pages((unsigned long)ti, get_order(THREAD_SIZE)); |
61c4628b SS |
39 | } |
40 | ||
41 | void arch_task_cache_init(void) | |
42 | { | |
43 | task_xstate_cachep = | |
44 | kmem_cache_create("task_xstate", xstate_size, | |
45 | __alignof__(union thread_xstate), | |
46 | SLAB_PANIC, NULL); | |
47 | } | |
7f424a8b | 48 | |
00dba564 TG |
49 | /* |
50 | * Idle related variables and functions | |
51 | */ | |
52 | unsigned long boot_option_idle_override = 0; | |
53 | EXPORT_SYMBOL(boot_option_idle_override); | |
54 | ||
55 | /* | |
56 | * Powermanagement idle function, if any.. | |
57 | */ | |
58 | void (*pm_idle)(void); | |
59 | EXPORT_SYMBOL(pm_idle); | |
60 | ||
61 | #ifdef CONFIG_X86_32 | |
62 | /* | |
63 | * This halt magic was a workaround for ancient floppy DMA | |
64 | * wreckage. It should be safe to remove. | |
65 | */ | |
66 | static int hlt_counter; | |
67 | void disable_hlt(void) | |
68 | { | |
69 | hlt_counter++; | |
70 | } | |
71 | EXPORT_SYMBOL(disable_hlt); | |
72 | ||
73 | void enable_hlt(void) | |
74 | { | |
75 | hlt_counter--; | |
76 | } | |
77 | EXPORT_SYMBOL(enable_hlt); | |
78 | ||
79 | static inline int hlt_use_halt(void) | |
80 | { | |
81 | return (!hlt_counter && boot_cpu_data.hlt_works_ok); | |
82 | } | |
83 | #else | |
84 | static inline int hlt_use_halt(void) | |
85 | { | |
86 | return 1; | |
87 | } | |
88 | #endif | |
89 | ||
90 | /* | |
91 | * We use this if we don't have any better | |
92 | * idle routine.. | |
93 | */ | |
94 | void default_idle(void) | |
95 | { | |
96 | if (hlt_use_halt()) { | |
97 | current_thread_info()->status &= ~TS_POLLING; | |
98 | /* | |
99 | * TS_POLLING-cleared state must be visible before we | |
100 | * test NEED_RESCHED: | |
101 | */ | |
102 | smp_mb(); | |
103 | ||
104 | if (!need_resched()) | |
105 | safe_halt(); /* enables interrupts racelessly */ | |
106 | else | |
107 | local_irq_enable(); | |
108 | current_thread_info()->status |= TS_POLLING; | |
109 | } else { | |
110 | local_irq_enable(); | |
111 | /* loop is done by the caller */ | |
112 | cpu_relax(); | |
113 | } | |
114 | } | |
115 | #ifdef CONFIG_APM_MODULE | |
116 | EXPORT_SYMBOL(default_idle); | |
117 | #endif | |
118 | ||
7f424a8b PZ |
119 | static void do_nothing(void *unused) |
120 | { | |
121 | } | |
122 | ||
123 | /* | |
124 | * cpu_idle_wait - Used to ensure that all the CPUs discard old value of | |
125 | * pm_idle and update to new pm_idle value. Required while changing pm_idle | |
126 | * handler on SMP systems. | |
127 | * | |
128 | * Caller must have changed pm_idle to the new value before the call. Old | |
129 | * pm_idle value will not be used by any CPU after the return of this function. | |
130 | */ | |
131 | void cpu_idle_wait(void) | |
132 | { | |
133 | smp_mb(); | |
134 | /* kick all the CPUs so that they exit out of pm_idle */ | |
135 | smp_call_function(do_nothing, NULL, 0, 1); | |
136 | } | |
137 | EXPORT_SYMBOL_GPL(cpu_idle_wait); | |
138 | ||
139 | /* | |
140 | * This uses new MONITOR/MWAIT instructions on P4 processors with PNI, | |
141 | * which can obviate IPI to trigger checking of need_resched. | |
142 | * We execute MONITOR against need_resched and enter optimized wait state | |
143 | * through MWAIT. Whenever someone changes need_resched, we would be woken | |
144 | * up from MWAIT (without an IPI). | |
145 | * | |
146 | * New with Core Duo processors, MWAIT can take some hints based on CPU | |
147 | * capability. | |
148 | */ | |
149 | void mwait_idle_with_hints(unsigned long ax, unsigned long cx) | |
150 | { | |
151 | if (!need_resched()) { | |
152 | __monitor((void *)¤t_thread_info()->flags, 0, 0); | |
153 | smp_mb(); | |
154 | if (!need_resched()) | |
155 | __mwait(ax, cx); | |
156 | } | |
157 | } | |
158 | ||
159 | /* Default MONITOR/MWAIT with no hints, used for default C1 state */ | |
160 | static void mwait_idle(void) | |
161 | { | |
162 | if (!need_resched()) { | |
163 | __monitor((void *)¤t_thread_info()->flags, 0, 0); | |
164 | smp_mb(); | |
165 | if (!need_resched()) | |
166 | __sti_mwait(0, 0); | |
167 | else | |
168 | local_irq_enable(); | |
169 | } else | |
170 | local_irq_enable(); | |
171 | } | |
172 | ||
7f424a8b PZ |
173 | /* |
174 | * On SMP it's slightly faster (but much more power-consuming!) | |
175 | * to poll the ->work.need_resched flag instead of waiting for the | |
176 | * cross-CPU IPI to arrive. Use this option with caution. | |
177 | */ | |
178 | static void poll_idle(void) | |
179 | { | |
180 | local_irq_enable(); | |
181 | cpu_relax(); | |
182 | } | |
183 | ||
e9623b35 TG |
184 | /* |
185 | * mwait selection logic: | |
186 | * | |
187 | * It depends on the CPU. For AMD CPUs that support MWAIT this is | |
188 | * wrong. Family 0x10 and 0x11 CPUs will enter C1 on HLT. Powersavings | |
189 | * then depend on a clock divisor and current Pstate of the core. If | |
190 | * all cores of a processor are in halt state (C1) the processor can | |
191 | * enter the C1E (C1 enhanced) state. If mwait is used this will never | |
192 | * happen. | |
193 | * | |
194 | * idle=mwait overrides this decision and forces the usage of mwait. | |
195 | */ | |
09fd4b4e TG |
196 | |
197 | #define MWAIT_INFO 0x05 | |
198 | #define MWAIT_ECX_EXTENDED_INFO 0x01 | |
199 | #define MWAIT_EDX_C1 0xf0 | |
200 | ||
e9623b35 TG |
201 | static int __cpuinit mwait_usable(const struct cpuinfo_x86 *c) |
202 | { | |
09fd4b4e TG |
203 | u32 eax, ebx, ecx, edx; |
204 | ||
e9623b35 TG |
205 | if (force_mwait) |
206 | return 1; | |
207 | ||
09fd4b4e TG |
208 | if (c->cpuid_level < MWAIT_INFO) |
209 | return 0; | |
210 | ||
211 | cpuid(MWAIT_INFO, &eax, &ebx, &ecx, &edx); | |
212 | /* Check, whether EDX has extended info about MWAIT */ | |
213 | if (!(ecx & MWAIT_ECX_EXTENDED_INFO)) | |
214 | return 1; | |
215 | ||
216 | /* | |
217 | * edx enumeratios MONITOR/MWAIT extensions. Check, whether | |
218 | * C1 supports MWAIT | |
219 | */ | |
220 | return (edx & MWAIT_EDX_C1); | |
e9623b35 TG |
221 | } |
222 | ||
aa276e1c TG |
223 | /* |
224 | * Check for AMD CPUs, which have potentially C1E support | |
225 | */ | |
226 | static int __cpuinit check_c1e_idle(const struct cpuinfo_x86 *c) | |
227 | { | |
228 | if (c->x86_vendor != X86_VENDOR_AMD) | |
229 | return 0; | |
230 | ||
231 | if (c->x86 < 0x0F) | |
232 | return 0; | |
233 | ||
234 | /* Family 0x0f models < rev F do not have C1E */ | |
235 | if (c->x86 == 0x0f && c->x86_model < 0x40) | |
236 | return 0; | |
237 | ||
238 | return 1; | |
239 | } | |
240 | ||
241 | /* | |
242 | * C1E aware idle routine. We check for C1E active in the interrupt | |
243 | * pending message MSR. If we detect C1E, then we handle it the same | |
244 | * way as C3 power states (local apic timer and TSC stop) | |
245 | */ | |
246 | static void c1e_idle(void) | |
247 | { | |
248 | static cpumask_t c1e_mask = CPU_MASK_NONE; | |
249 | static int c1e_detected; | |
250 | ||
251 | if (need_resched()) | |
252 | return; | |
253 | ||
254 | if (!c1e_detected) { | |
255 | u32 lo, hi; | |
256 | ||
257 | rdmsr(MSR_K8_INT_PENDING_MSG, lo, hi); | |
258 | if (lo & K8_INTP_C1E_ACTIVE_MASK) { | |
259 | c1e_detected = 1; | |
260 | mark_tsc_unstable("TSC halt in C1E"); | |
261 | printk(KERN_INFO "System has C1E enabled\n"); | |
262 | } | |
263 | } | |
264 | ||
265 | if (c1e_detected) { | |
266 | int cpu = smp_processor_id(); | |
267 | ||
268 | if (!cpu_isset(cpu, c1e_mask)) { | |
269 | cpu_set(cpu, c1e_mask); | |
270 | /* Force broadcast so ACPI can not interfere */ | |
271 | clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_FORCE, | |
272 | &cpu); | |
273 | printk(KERN_INFO "Switch to broadcast mode on CPU%d\n", | |
274 | cpu); | |
275 | } | |
276 | clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu); | |
277 | default_idle(); | |
278 | local_irq_disable(); | |
279 | clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu); | |
280 | local_irq_enable(); | |
281 | } else | |
282 | default_idle(); | |
283 | } | |
284 | ||
7f424a8b PZ |
285 | void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c) |
286 | { | |
7f424a8b PZ |
287 | #ifdef CONFIG_X86_SMP |
288 | if (pm_idle == poll_idle && smp_num_siblings > 1) { | |
289 | printk(KERN_WARNING "WARNING: polling idle and HT enabled," | |
290 | " performance may degrade.\n"); | |
291 | } | |
292 | #endif | |
6ddd2a27 TG |
293 | if (pm_idle) |
294 | return; | |
295 | ||
e9623b35 | 296 | if (cpu_has(c, X86_FEATURE_MWAIT) && mwait_usable(c)) { |
7f424a8b | 297 | /* |
7f424a8b PZ |
298 | * One CPU supports mwait => All CPUs supports mwait |
299 | */ | |
6ddd2a27 TG |
300 | printk(KERN_INFO "using mwait in idle threads.\n"); |
301 | pm_idle = mwait_idle; | |
aa276e1c TG |
302 | } else if (check_c1e_idle(c)) { |
303 | printk(KERN_INFO "using C1E aware idle routine\n"); | |
304 | pm_idle = c1e_idle; | |
6ddd2a27 TG |
305 | } else |
306 | pm_idle = default_idle; | |
7f424a8b PZ |
307 | } |
308 | ||
309 | static int __init idle_setup(char *str) | |
310 | { | |
311 | if (!strcmp(str, "poll")) { | |
312 | printk("using polling idle threads.\n"); | |
313 | pm_idle = poll_idle; | |
314 | } else if (!strcmp(str, "mwait")) | |
315 | force_mwait = 1; | |
316 | else | |
317 | return -1; | |
318 | ||
319 | boot_option_idle_override = 1; | |
320 | return 0; | |
321 | } | |
322 | early_param("idle", idle_setup); | |
323 |