Question

使用ARM GCC工具链可以很好地构建这个内核..出于某种原因，aarch64工具链会抛出此错误。

kernel/sched/core_ctl.c: In function 'cpufreq_gov_cb':
kernel/sched/core_ctl.c:1086:25: error: dereferencing pointer to incomplete type
   core_ctl_set_busy(info->cpu, info->load);
                         ^
kernel/sched/core_ctl.c:1086:36: error: dereferencing pointer to incomplete type
   core_ctl_set_busy(info->cpu, info->load);
                                    ^
scripts/Makefile.build:257: recipe for target 'kernel/sched/core_ctl.o' failed

这是＆＃34; cpu＆＃34;已定义（无法在c文件中找到负载）：

#include <linux/init.h>
#include <linux/notifier.h>
#include <linux/cpu.h>
#include <linux/cpumask.h>
#include <linux/cpufreq.h>
#include <linux/timer.h>
#include <linux/kthread.h>
#include <linux/sched.h>
#include <linux/sched/rt.h>
#include <linux/mutex.h>

#include <trace/events/sched.h>

#define MAX_CPUS_PER_GROUP 4

struct cpu_data {
    /* Per CPU data. */
    bool    inited;
    bool    online;
    bool    rejected;
    bool    is_busy;
    bool    not_preferred;
    unsigned int busy;
    unsigned int cpu;
    struct list_head sib;
    unsigned int first_cpu;
    struct list_head pending_sib;

    /* Per cluster data set only on first CPU */
    unsigned int min_cpus;
    unsigned int max_cpus;
    unsigned int offline_delay_ms;
    unsigned int busy_up_thres[MAX_CPUS_PER_GROUP];
    unsigned int busy_down_thres[MAX_CPUS_PER_GROUP];
    unsigned int online_cpus;
    unsigned int avail_cpus;
    unsigned int num_cpus;
    unsigned int need_cpus;
    unsigned int task_thres;
    s64 need_ts;
    struct list_head lru;
    bool pending;
    spinlock_t pending_lock;
    bool is_big_cluster;
    int nrrun;
    bool nrrun_changed;
    struct timer_list timer;
    struct task_struct *hotplug_thread;
    struct kobject kobj;
    struct list_head pending_lru;
    bool disabled;
};

什么可以使编译器报告不完整类型？我对C中的指针和结构不太熟悉，但是无法解决这个问题。

Answer 1

在您的计算机上编译kernel / sched / core_ctl.c时，似乎缺少struct cpufreq_govinfo的头文件。

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在我的机器（ARM：CortexA7）上，GCC编译器不会抛出编译错误，因为正确包含了以下头文件。

struct cpufreq_govinfo {
 unsigned int cpu;
 unsigned int load;
 unsigned int sampling_rate_us;
};

此外，以下补丁将使您在构建Linux内核后拥有预处理文件。

  kernel/include/linux/cpufreq.h

如果您查看预处理文件.tmp_core_ctl.i，您将能够看到所有用于编译core_ctl.c的头文件。

Android内核构建错误：core_ctl.c - 解除引用指向不完整类型的指针

1 个答案: