(linux 内核) 在 available_filter_functions 中添加新函数

问题描述

硬件 - Raspberry pi 4 Model B 8GB 操作系统 - 树莓派操作系统 Buster(10)(2020-05-27-raspios-buster-full-armhf.img)(linux kerenl 4.19.y)

我在 proc.c 中添加了 rpi_get_interrupt_info() 并修改了 show_interrupts()

rpi_get_interrupt_info() 和 show_interrupts() 的完整代码

void rpi_get_interrupt_info(struct irqaction *action_p)
{
    unsigned int irq_num = action_p->irq;
    void *irq_handler = NULL;
    
    if (action_p->handler) {
        irq_handler = (void*)action_p->handler;
    }

    if (irq_handler) {
        trace_printk("[%s] %d: %s,irq_handler: %pS \n",current->comm,irq_num,action_p->name,irq_handler);
    }
}
    
int show_interrupts(struct seq_file *p,void *v)
{
    static int prec;

    unsigned long flags,any_count = 0;
    int i = *(loff_t *) v,j;
    struct irqaction *action;
    struct irq_desc *desc;

    if (i > ACTUAL_NR_IRQS)
        return 0;

    if (i == ACTUAL_NR_IRQS)
        return arch_show_interrupts(p,prec);

    /* print header and calculate the width of the first column */
    if (i == 0) {
        for (prec = 3,j = 1000; prec < 10 && j <= nr_irqs; ++prec)
            j *= 10;

        seq_printf(p,"%*s",prec + 8,"");
        for_each_online_cpu(j)
            seq_printf(p,"CPU%-8d",j);
        seq_putc(p,'\n');
    }

    rcu_read_lock();
    desc = irq_to_desc(i);
    if (!desc)
        goto outsparse;

    if (desc->kstat_irqs)
        for_each_online_cpu(j)
            any_count |= *per_cpu_ptr(desc->kstat_irqs,j);

    if ((!desc->action || irq_desc_is_chained(desc)) && !any_count)
        goto outsparse;

    seq_printf(p,"%*d: ",prec,i);
    for_each_online_cpu(j)
        seq_printf(p,"%10u ",desc->kstat_irqs ?
                    *per_cpu_ptr(desc->kstat_irqs,j) : 0);

    raw_spin_lock_irqsave(&desc->lock,flags);
    if (desc->irq_data.chip) {
        if (desc->irq_data.chip->irq_print_chip)
            desc->irq_data.chip->irq_print_chip(&desc->irq_data,p);
        else if (desc->irq_data.chip->name)
            seq_printf(p," %8s",desc->irq_data.chip->name);
        else
            seq_printf(p,"-");
    } else {
        seq_printf(p,"None");
    }
    if (desc->irq_data.domain)
        seq_printf(p," %*d",(int) desc->irq_data.hwirq);
    else
        seq_printf(p," %*s","");
#ifdef CONFIG_GENERIC_IRQ_SHOW_LEVEL
    seq_printf(p," %-8s",irqd_is_level_type(&desc->irq_data) ? "Level" : "Edge");
#endif
    if (desc->name)
        seq_printf(p,"-%-8s",desc->name);

    action = desc->action;

    if (action)
        rpi_get_interrupt_info(action);

    if (action) {
        seq_printf(p,"  %s",action->name);
        while ((action = action->next) != NULL)
            seq_printf(p,",%s",action->name);
    }

    seq_putc(p,'\n');
    raw_spin_unlock_irqrestore(&desc->lock,flags);
outsparse:
    rcu_read_unlock();
    return 0;
}
#endif

我更改的代码

void rpi_get_interrupt_info(struct irqaction *action_p)
{
    unsigned int irq_num = action_p->irq;
    void *irq_handler = NULL;
    
    if (action_p->handler) {
        irq_handler = (void*)action_p->handler;
    }

    if (irq_handler) {
        trace_printk("[%s] %d: %s,irq_handler);
    }
}

....

if (action)
        rpi_get_interrupt_info(action);

当我尝试 echo rpi_get_interrupt_info > /sys/kernel/debug/tracing/set_ftrace_filter 时，它显示 echo: write error: Invalid argument

所以我查看了/sys/kernel/debug/tracing/available_filter_functions，没有rpi_get_interrupt_info

我试过 noinline void rpi_get_interrupt_info(struct irqaction *action_p)，但没有用。

解决方法

抱歉，我在配置 bcm2711_defconfig 文件时犯了一些错误。感谢所有想帮助我的人:)