1 #include <linux/errno.h>
2 #include <linux/kernel.h>
5 #include <linux/prctl.h>
6 #include <linux/slab.h>
7 #include <linux/sched.h>
8 #include <linux/module.h>
10 #include <linux/clockchips.h>
11 #include <linux/random.h>
12 #include <linux/user-return-notifier.h>
13 #include <linux/dmi.h>
14 #include <linux/utsname.h>
15 #include <trace/events/power.h>
16 #include <linux/hw_breakpoint.h>
18 #include <asm/system.h>
20 #include <asm/syscalls.h>
22 #include <asm/uaccess.h>
24 #include <asm/debugreg.h>
26 struct kmem_cache
*task_xstate_cachep
;
27 EXPORT_SYMBOL_GPL(task_xstate_cachep
);
29 int arch_dup_task_struct(struct task_struct
*dst
, struct task_struct
*src
)
34 if (fpu_allocated(&src
->thread
.fpu
)) {
35 memset(&dst
->thread
.fpu
, 0, sizeof(dst
->thread
.fpu
));
36 ret
= fpu_alloc(&dst
->thread
.fpu
);
39 fpu_copy(&dst
->thread
.fpu
, &src
->thread
.fpu
);
44 void free_thread_xstate(struct task_struct
*tsk
)
46 fpu_free(&tsk
->thread
.fpu
);
49 void free_thread_info(struct thread_info
*ti
)
51 free_thread_xstate(ti
->task
);
52 free_pages((unsigned long)ti
, get_order(THREAD_SIZE
));
55 void arch_task_cache_init(void)
58 kmem_cache_create("task_xstate", xstate_size
,
59 __alignof__(union thread_xstate
),
60 SLAB_PANIC
| SLAB_NOTRACK
, NULL
);
64 * Free current thread data structures etc..
66 void exit_thread(void)
68 struct task_struct
*me
= current
;
69 struct thread_struct
*t
= &me
->thread
;
70 unsigned long *bp
= t
->io_bitmap_ptr
;
73 struct tss_struct
*tss
= &per_cpu(init_tss
, get_cpu());
75 t
->io_bitmap_ptr
= NULL
;
76 clear_thread_flag(TIF_IO_BITMAP
);
78 * Careful, clear this in the TSS too:
80 memset(tss
->io_bitmap
, 0xff, t
->io_bitmap_max
);
87 void show_regs(struct pt_regs
*regs
)
90 show_trace(NULL
, regs
, (unsigned long *)kernel_stack_pointer(regs
), 0);
93 void show_regs_common(void)
95 const char *vendor
, *product
, *board
;
97 vendor
= dmi_get_system_info(DMI_SYS_VENDOR
);
100 product
= dmi_get_system_info(DMI_PRODUCT_NAME
);
104 /* Board Name is optional */
105 board
= dmi_get_system_info(DMI_BOARD_NAME
);
107 printk(KERN_CONT
"\n");
108 printk(KERN_DEFAULT
"Pid: %d, comm: %.20s %s %s %.*s",
109 current
->pid
, current
->comm
, print_tainted(),
110 init_utsname()->release
,
111 (int)strcspn(init_utsname()->version
, " "),
112 init_utsname()->version
);
113 printk(KERN_CONT
" %s %s", vendor
, product
);
115 printk(KERN_CONT
"/%s", board
);
116 printk(KERN_CONT
"\n");
119 void flush_thread(void)
121 struct task_struct
*tsk
= current
;
123 flush_ptrace_hw_breakpoint(tsk
);
124 memset(tsk
->thread
.tls_array
, 0, sizeof(tsk
->thread
.tls_array
));
126 * Forget coprocessor state..
128 tsk
->fpu_counter
= 0;
133 static void hard_disable_TSC(void)
135 write_cr4(read_cr4() | X86_CR4_TSD
);
138 void disable_TSC(void)
141 if (!test_and_set_thread_flag(TIF_NOTSC
))
143 * Must flip the CPU state synchronously with
144 * TIF_NOTSC in the current running context.
150 static void hard_enable_TSC(void)
152 write_cr4(read_cr4() & ~X86_CR4_TSD
);
155 static void enable_TSC(void)
158 if (test_and_clear_thread_flag(TIF_NOTSC
))
160 * Must flip the CPU state synchronously with
161 * TIF_NOTSC in the current running context.
167 int get_tsc_mode(unsigned long adr
)
171 if (test_thread_flag(TIF_NOTSC
))
172 val
= PR_TSC_SIGSEGV
;
176 return put_user(val
, (unsigned int __user
*)adr
);
179 int set_tsc_mode(unsigned int val
)
181 if (val
== PR_TSC_SIGSEGV
)
183 else if (val
== PR_TSC_ENABLE
)
191 void __switch_to_xtra(struct task_struct
*prev_p
, struct task_struct
*next_p
,
192 struct tss_struct
*tss
)
194 struct thread_struct
*prev
, *next
;
196 prev
= &prev_p
->thread
;
197 next
= &next_p
->thread
;
199 if (test_tsk_thread_flag(prev_p
, TIF_BLOCKSTEP
) ^
200 test_tsk_thread_flag(next_p
, TIF_BLOCKSTEP
)) {
201 unsigned long debugctl
= get_debugctlmsr();
203 debugctl
&= ~DEBUGCTLMSR_BTF
;
204 if (test_tsk_thread_flag(next_p
, TIF_BLOCKSTEP
))
205 debugctl
|= DEBUGCTLMSR_BTF
;
207 update_debugctlmsr(debugctl
);
210 if (test_tsk_thread_flag(prev_p
, TIF_NOTSC
) ^
211 test_tsk_thread_flag(next_p
, TIF_NOTSC
)) {
212 /* prev and next are different */
213 if (test_tsk_thread_flag(next_p
, TIF_NOTSC
))
219 if (test_tsk_thread_flag(next_p
, TIF_IO_BITMAP
)) {
221 * Copy the relevant range of the IO bitmap.
222 * Normally this is 128 bytes or less:
224 memcpy(tss
->io_bitmap
, next
->io_bitmap_ptr
,
225 max(prev
->io_bitmap_max
, next
->io_bitmap_max
));
226 } else if (test_tsk_thread_flag(prev_p
, TIF_IO_BITMAP
)) {
228 * Clear any possible leftover bits:
230 memset(tss
->io_bitmap
, 0xff, prev
->io_bitmap_max
);
232 propagate_user_return_notify(prev_p
, next_p
);
235 int sys_fork(struct pt_regs
*regs
)
237 return do_fork(SIGCHLD
, regs
->sp
, regs
, 0, NULL
, NULL
);
241 * This is trivial, and on the face of it looks like it
242 * could equally well be done in user mode.
244 * Not so, for quite unobvious reasons - register pressure.
245 * In user mode vfork() cannot have a stack frame, and if
246 * done by calling the "clone()" system call directly, you
247 * do not have enough call-clobbered registers to hold all
248 * the information you need.
250 int sys_vfork(struct pt_regs
*regs
)
252 return do_fork(CLONE_VFORK
| CLONE_VM
| SIGCHLD
, regs
->sp
, regs
, 0,
257 sys_clone(unsigned long clone_flags
, unsigned long newsp
,
258 void __user
*parent_tid
, void __user
*child_tid
, struct pt_regs
*regs
)
262 return do_fork(clone_flags
, newsp
, regs
, 0, parent_tid
, child_tid
);
266 * This gets run with %si containing the
267 * function to call, and %di containing
270 extern void kernel_thread_helper(void);
273 * Create a kernel thread
275 int kernel_thread(int (*fn
)(void *), void *arg
, unsigned long flags
)
279 memset(®s
, 0, sizeof(regs
));
281 regs
.si
= (unsigned long) fn
;
282 regs
.di
= (unsigned long) arg
;
287 regs
.fs
= __KERNEL_PERCPU
;
288 regs
.gs
= __KERNEL_STACK_CANARY
;
290 regs
.ss
= __KERNEL_DS
;
294 regs
.ip
= (unsigned long) kernel_thread_helper
;
295 regs
.cs
= __KERNEL_CS
| get_kernel_rpl();
296 regs
.flags
= X86_EFLAGS_IF
| 0x2;
298 /* Ok, create the new process.. */
299 return do_fork(flags
| CLONE_VM
| CLONE_UNTRACED
, 0, ®s
, 0, NULL
, NULL
);
301 EXPORT_SYMBOL(kernel_thread
);
304 * sys_execve() executes a new program.
306 long sys_execve(const char __user
*name
,
307 const char __user
*const __user
*argv
,
308 const char __user
*const __user
*envp
, struct pt_regs
*regs
)
313 filename
= getname(name
);
314 error
= PTR_ERR(filename
);
315 if (IS_ERR(filename
))
317 error
= do_execve(filename
, argv
, envp
, regs
);
321 /* Make sure we don't return using sysenter.. */
322 set_thread_flag(TIF_IRET
);
331 * Idle related variables and functions
333 unsigned long boot_option_idle_override
= IDLE_NO_OVERRIDE
;
334 EXPORT_SYMBOL(boot_option_idle_override
);
337 * Powermanagement idle function, if any..
339 void (*pm_idle
)(void);
340 #ifdef CONFIG_APM_MODULE
341 EXPORT_SYMBOL(pm_idle
);
346 * This halt magic was a workaround for ancient floppy DMA
347 * wreckage. It should be safe to remove.
349 static int hlt_counter
;
350 void disable_hlt(void)
354 EXPORT_SYMBOL(disable_hlt
);
356 void enable_hlt(void)
360 EXPORT_SYMBOL(enable_hlt
);
362 static inline int hlt_use_halt(void)
364 return (!hlt_counter
&& boot_cpu_data
.hlt_works_ok
);
367 static inline int hlt_use_halt(void)
374 * We use this if we don't have any better
377 void default_idle(void)
379 if (hlt_use_halt()) {
380 trace_power_start(POWER_CSTATE
, 1, smp_processor_id());
381 trace_cpu_idle(1, smp_processor_id());
382 current_thread_info()->status
&= ~TS_POLLING
;
384 * TS_POLLING-cleared state must be visible before we
390 safe_halt(); /* enables interrupts racelessly */
393 current_thread_info()->status
|= TS_POLLING
;
394 trace_power_end(smp_processor_id());
395 trace_cpu_idle(PWR_EVENT_EXIT
, smp_processor_id());
398 /* loop is done by the caller */
402 #ifdef CONFIG_APM_MODULE
403 EXPORT_SYMBOL(default_idle
);
406 void stop_this_cpu(void *dummy
)
412 set_cpu_online(smp_processor_id(), false);
413 disable_local_APIC();
416 if (hlt_works(smp_processor_id()))
421 static void do_nothing(void *unused
)
426 * cpu_idle_wait - Used to ensure that all the CPUs discard old value of
427 * pm_idle and update to new pm_idle value. Required while changing pm_idle
428 * handler on SMP systems.
430 * Caller must have changed pm_idle to the new value before the call. Old
431 * pm_idle value will not be used by any CPU after the return of this function.
433 void cpu_idle_wait(void)
436 /* kick all the CPUs so that they exit out of pm_idle */
437 smp_call_function(do_nothing
, NULL
, 1);
439 EXPORT_SYMBOL_GPL(cpu_idle_wait
);
442 * This uses new MONITOR/MWAIT instructions on P4 processors with PNI,
443 * which can obviate IPI to trigger checking of need_resched.
444 * We execute MONITOR against need_resched and enter optimized wait state
445 * through MWAIT. Whenever someone changes need_resched, we would be woken
446 * up from MWAIT (without an IPI).
448 * New with Core Duo processors, MWAIT can take some hints based on CPU
451 void mwait_idle_with_hints(unsigned long ax
, unsigned long cx
)
453 if (!need_resched()) {
454 if (this_cpu_has(X86_FEATURE_CLFLUSH_MONITOR
))
455 clflush((void *)¤t_thread_info()->flags
);
457 __monitor((void *)¤t_thread_info()->flags
, 0, 0);
464 /* Default MONITOR/MWAIT with no hints, used for default C1 state */
465 static void mwait_idle(void)
467 if (!need_resched()) {
468 trace_power_start(POWER_CSTATE
, 1, smp_processor_id());
469 trace_cpu_idle(1, smp_processor_id());
470 if (this_cpu_has(X86_FEATURE_CLFLUSH_MONITOR
))
471 clflush((void *)¤t_thread_info()->flags
);
473 __monitor((void *)¤t_thread_info()->flags
, 0, 0);
479 trace_power_end(smp_processor_id());
480 trace_cpu_idle(PWR_EVENT_EXIT
, smp_processor_id());
486 * On SMP it's slightly faster (but much more power-consuming!)
487 * to poll the ->work.need_resched flag instead of waiting for the
488 * cross-CPU IPI to arrive. Use this option with caution.
490 static void poll_idle(void)
492 trace_power_start(POWER_CSTATE
, 0, smp_processor_id());
493 trace_cpu_idle(0, smp_processor_id());
495 while (!need_resched())
497 trace_power_end(smp_processor_id());
498 trace_cpu_idle(PWR_EVENT_EXIT
, smp_processor_id());
502 * mwait selection logic:
504 * It depends on the CPU. For AMD CPUs that support MWAIT this is
505 * wrong. Family 0x10 and 0x11 CPUs will enter C1 on HLT. Powersavings
506 * then depend on a clock divisor and current Pstate of the core. If
507 * all cores of a processor are in halt state (C1) the processor can
508 * enter the C1E (C1 enhanced) state. If mwait is used this will never
511 * idle=mwait overrides this decision and forces the usage of mwait.
514 #define MWAIT_INFO 0x05
515 #define MWAIT_ECX_EXTENDED_INFO 0x01
516 #define MWAIT_EDX_C1 0xf0
518 int mwait_usable(const struct cpuinfo_x86
*c
)
520 u32 eax
, ebx
, ecx
, edx
;
522 if (boot_option_idle_override
== IDLE_FORCE_MWAIT
)
525 if (c
->cpuid_level
< MWAIT_INFO
)
528 cpuid(MWAIT_INFO
, &eax
, &ebx
, &ecx
, &edx
);
529 /* Check, whether EDX has extended info about MWAIT */
530 if (!(ecx
& MWAIT_ECX_EXTENDED_INFO
))
534 * edx enumeratios MONITOR/MWAIT extensions. Check, whether
537 return (edx
& MWAIT_EDX_C1
);
540 bool amd_e400_c1e_detected
;
541 EXPORT_SYMBOL(amd_e400_c1e_detected
);
543 static cpumask_var_t amd_e400_c1e_mask
;
545 void amd_e400_remove_cpu(int cpu
)
547 if (amd_e400_c1e_mask
!= NULL
)
548 cpumask_clear_cpu(cpu
, amd_e400_c1e_mask
);
552 * AMD Erratum 400 aware idle routine. We check for C1E active in the interrupt
553 * pending message MSR. If we detect C1E, then we handle it the same
554 * way as C3 power states (local apic timer and TSC stop)
556 static void amd_e400_idle(void)
561 if (!amd_e400_c1e_detected
) {
564 rdmsr(MSR_K8_INT_PENDING_MSG
, lo
, hi
);
566 if (lo
& K8_INTP_C1E_ACTIVE_MASK
) {
567 amd_e400_c1e_detected
= true;
568 if (!boot_cpu_has(X86_FEATURE_NONSTOP_TSC
))
569 mark_tsc_unstable("TSC halt in AMD C1E");
570 printk(KERN_INFO
"System has AMD C1E enabled\n");
574 if (amd_e400_c1e_detected
) {
575 int cpu
= smp_processor_id();
577 if (!cpumask_test_cpu(cpu
, amd_e400_c1e_mask
)) {
578 cpumask_set_cpu(cpu
, amd_e400_c1e_mask
);
580 * Force broadcast so ACPI can not interfere.
582 clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_FORCE
,
584 printk(KERN_INFO
"Switch to broadcast mode on CPU%d\n",
587 clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER
, &cpu
);
592 * The switch back from broadcast mode needs to be
593 * called with interrupts disabled.
596 clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT
, &cpu
);
602 void __cpuinit
select_idle_routine(const struct cpuinfo_x86
*c
)
605 if (pm_idle
== poll_idle
&& smp_num_siblings
> 1) {
606 printk_once(KERN_WARNING
"WARNING: polling idle and HT enabled,"
607 " performance may degrade.\n");
613 if (cpu_has(c
, X86_FEATURE_MWAIT
) && mwait_usable(c
)) {
615 * One CPU supports mwait => All CPUs supports mwait
617 printk(KERN_INFO
"using mwait in idle threads.\n");
618 pm_idle
= mwait_idle
;
619 } else if (cpu_has_amd_erratum(amd_erratum_400
)) {
620 /* E400: APIC timer interrupt does not wake up CPU from C1e */
621 printk(KERN_INFO
"using AMD E400 aware idle routine\n");
622 pm_idle
= amd_e400_idle
;
624 pm_idle
= default_idle
;
627 void __init
init_amd_e400_c1e_mask(void)
629 /* If we're using amd_e400_idle, we need to allocate amd_e400_c1e_mask. */
630 if (pm_idle
== amd_e400_idle
)
631 zalloc_cpumask_var(&amd_e400_c1e_mask
, GFP_KERNEL
);
634 static int __init
idle_setup(char *str
)
639 if (!strcmp(str
, "poll")) {
640 printk("using polling idle threads.\n");
642 boot_option_idle_override
= IDLE_POLL
;
643 } else if (!strcmp(str
, "mwait")) {
644 boot_option_idle_override
= IDLE_FORCE_MWAIT
;
645 WARN_ONCE(1, "\"idle=mwait\" will be removed in 2012\n");
646 } else if (!strcmp(str
, "halt")) {
648 * When the boot option of idle=halt is added, halt is
649 * forced to be used for CPU idle. In such case CPU C2/C3
650 * won't be used again.
651 * To continue to load the CPU idle driver, don't touch
652 * the boot_option_idle_override.
654 pm_idle
= default_idle
;
655 boot_option_idle_override
= IDLE_HALT
;
656 } else if (!strcmp(str
, "nomwait")) {
658 * If the boot option of "idle=nomwait" is added,
659 * it means that mwait will be disabled for CPU C2/C3
660 * states. In such case it won't touch the variable
661 * of boot_option_idle_override.
663 boot_option_idle_override
= IDLE_NOMWAIT
;
669 early_param("idle", idle_setup
);
671 unsigned long arch_align_stack(unsigned long sp
)
673 if (!(current
->personality
& ADDR_NO_RANDOMIZE
) && randomize_va_space
)
674 sp
-= get_random_int() % 8192;
678 unsigned long arch_randomize_brk(struct mm_struct
*mm
)
680 unsigned long range_end
= mm
->brk
+ 0x02000000;
681 return randomize_range(mm
->brk
, range_end
, 0) ? : mm
->brk
;