big.LITTLE

https://github.com/gatieme/CC-A80-kernel-source/blob/master/3.4/kernel/sched/fair.c

https://github.com/gatieme/big.LITTLE/blob/master/3.10/kernel/sched/fair.c

https://github.com/meizuosc/m681/blob/master/kernel/sched/fair.c

#1 CONFIG_OF 宏的问题

##1.1 启用

我们启用了 CONFIG_OF

##1.2 引入的问题

但是发现驱动中很多 OF 相关的函数, 未定义

drivers/clocksource/sunxi_timer.c

error: implicit declaration of function ‘of_clk_get’ [-Werror=implicit-function-declaration]

drivers/pinctrl/pinctrl-sunxi.c
error: implicit declaration of function ‘of_property_for_each_string’ [-Werror=implicit-function-declaration]

解决办法

1 实现未定义的函数

2 在驱动中取消 CONFIG_OF 宏

3 用其他函数替代

4 #if 0 屏蔽有问题的代码

#2 arch/arm/kernel/topology.c

其中未定义

static DEFINE_PER_CPU(unsigned long, cpu_scale);

及其函数接口, 于是我们定义了宏

/*  add by gatieme(ChengJean) @ 2016-12-08 00:19 */
#ifdef CONFIG_CPU_POWER_MANAGEMENT
#endif

#3 kernel/stop_machine.c

未定义 cpu_stopper_task, 及其函数

#4 CONFIG_NO_HZ_COMMON

未定义CONFIG_NO_HZ_COMMON 宏, 因此很多函数未定义

#5 arm-linux-gnueabi-nm

/home/gatieme/Work/Arm/Kernel/3.4/GitHub/3.4/scripts/mksysmap: line 44: ~/Work/Arm/Board/cubieboard/cc-a80/cc-a80-linux-sdk/tools/crosscompiler/bin/arm-linux-gnueabi-nm: No such file or directory

#6 runnable_load_avg

cpu_rq(cpu)->load.weight; 均被修改为 cpu_rq(cpu)->cfs.runnable_load_avg;

tg_load_down task_h_load task_h_load

#7 lb_env中定义的问题

#8 自打6930-7467行开始 update_sg_lb_stats函数参数变换 update_sd_pick_busiest update_sd_lb_stats check_asym_packing calculate_imbalance find_busiest_queue

#9 enqueue_entity_load_avg 和 dequeue_entity_load_avg

#10 启动过程

[init/main.c] start_kernel

        setup_arch(&command_line);
	mm_init_owner(&init_mm, &init_task);
	mm_init_cpumask(&init_mm);
	setup_command_line(command_line);
	setup_nr_cpu_ids();
	setup_per_cpu_areas();

[arch/arm/kernel/setup.c] setup_arch

#ifdef CONFIG_SMP
        if (is_smp()) {
                if (!mdesc->smp_init || !mdesc->smp_init())
                        smp_set_ops(mdesc->smp);
                        smp_init_cpus();        /* add by gatieme for debug */
                        smp_build_mpidr_hash();
        }
#endif

[arch/arm/kernel/smp.c] smp_init_cpus

        if (smp_ops.smp_init_cpus)
                smp_ops.smp_init_cpus();

[arch/arm/common/mcpm_platsmp.c]

.smp_init_cpus = mcpm_smp_init_cpus,

[arch/arm/common/mcpm_entry.c] mcmp_smp_init_cpus