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02全志r58平臺Android4.4.4下關閉內核中的CPU的開啟關閉提示

2017/8/18 13:53

版本：V1.0

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開發板：SC5806（全志R58平臺）

SDK：android4.4.4

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1、系統編譯：（略）

原始編譯的系統，在串口中會有很多打印：（并且還是不停的顯示打印！）

[ 3277.071614] CPU1: shutdown

[ 3277.534023] CPU2: shutdown

[ 3277.080857] CPU1: Booted secondary processor

[ 3277.540563] CPU2: Booted secondary processor

[ 3275.490031] CPU3: Booted secondary processor

[ 3279.121504] CPU2: shutdown

[ 3279.552958] CPU3: shutdown

[ 3279.577345] CPU1: shutdown

[ 3279.580034] CPU1: Booted secondary processor

[ 3279.130678] CPU2: Booted secondary processor

[ 3279.561647] CPU3: Booted secondary processor

[ 3282.023760] CPU2: shutdown

[ 3282.032309] CPU2: Booted secondary processor

[ 3283.102187] CPU3: shutdown

[ 3283.382554] CPU1: shutdown

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2、

W:\vxiaoyu_s5k5eya\lichee\linux-3.4\arch\arm\kernel\smp.c

/*

?* called on the thread which is asking for a CPU to be shutdown -

?* waits until shutdown has completed, or it is timed out.

?*/

void __cpuinit __cpu_die(unsigned int cpu)

{

if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) {

pr_err("CPU%u: cpu didn't die\n", cpu);

return;

}

//printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);

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if (!platform_cpu_kill(cpu))

printk("CPU%u: unable to kill\n", cpu);

}

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/*

?* This is the secondary CPU boot entry. ?We're using this CPUs

?* idle thread stack, but a set of temporary page tables.

?*/

asmlinkage void __cpuinit secondary_start_kernel(void)

{

struct mm_struct *mm = &init_mm;

unsigned int cpu;

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/*

?* The identity mapping is uncached (strongly ordered), so

?* switch away from it before attempting any exclusive accesses.

?*/

cpu_switch_mm(mm->pgd, mm);

enter_lazy_tlb(mm, current);

local_flush_tlb_all();

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/*

?* All kernel threads share the same mm context; grab a

?* reference and switch to it.

?*/

cpu = smp_processor_id();

atomic_inc(&mm->mm_count);

current->active_mm = mm;

cpumask_set_cpu(cpu, mm_cpumask(mm));

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//printk("CPU%u: Booted secondary processor\n", cpu);

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cpu_init();

preempt_disable();

trace_hardirqs_off();

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/*

?* Give the platform a chance to do its own initialisation.

?*/

platform_secondary_init(cpu);

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notify_cpu_starting(cpu);

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calibrate_delay();

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smp_store_cpu_info(cpu);

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/*

?* OK, now it's safe to let the boot CPU continue. ?Wait for

?* the CPU migration code to notice that the CPU is online

?* before we continue - which happens after __cpu_up returns.

?*/

set_cpu_online(cpu, true);

complete(&cpu_running);

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local_irq_enable();

local_fiq_enable();

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/*

?* OK, it's off to the idle thread for us

?*/

cpu_idle();

}

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3、重新編譯boot/內核打包即可！

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轉載于:https://www.cnblogs.com/wb4916/p/9923005.html

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