pci_disable_msi糟糕问题

我正在尝试编写一个内核模块来处理PCIe设备的MSI中断。我为我的驱动程序写了一个简单的骨架轮廓，当我尝试调用'pci_disable_msi（dev）'时，我得到无法处理内核NULL指针解除引用错误。我完全按照/Documentation/PCI/MSI-HOWTO.txt中的描述进行操作，在我看来，我不应该得到这个错误。这是一个错误还是我的设置不正确？根据发生的最后一次打印判断，当我调用pci_disable_msi（）时，我确信它发生在fpga_remove（）处。（显然，这occures当我移动模块），pci_disable_msi糟糕问题

static struct pci_driver fpga_driver = { 
     .name  = "PCIe_test", 
     .id_table = fpga_dev_table, 
     .probe  = fpga_probe, 
     .remove  = fpga_remove, 
     .suspend = fpga_suspend, 
     .resume  = fpga_resume, 
}; 

static irqreturn_t fpga_isr(int irq, struct pci_dev *dev) 
{ 

    printk(KERN_NOTICE "THIS is the ISR\n"); 

    return IRQ_HANDLED; 
} 


static int setup_MSI_interrupt(struct pci_dev *dev, int num_msi) 
{ 

    int result; 
    result = pci_enable_msi(dev); 
    if(result) 
    { 
     printk(KERN_WARNING "Could not enable MSI\n"); 
     return result; 

    } 
    printk(KERN_NOTICE "MSI has been enabled\n"); 
    printk(KERN_NOTICE "dev->irq line is %d", dev->irq); 

    result = request_irq(dev->irq, fpga_isr, IRQF_SHARED, fpga_driver.name, dev); 
    printk(KERN_NOTICE "Using IRQ num %d\n", dev->irq); 

    if (result) { 
     dev_err(&dev->dev, "Failed to allocate irq %d: %d\n", dev->irq, result); 
     goto exit1; 
    } 
     dev_info(&dev->dev, "FPGA using PCIe Interrupt\n"); 

    return 0; 
exit1: 
    return -1; 
} 

static int fpga_probe(struct pci_dev *dev, const struct pci_device_id *id) 
{ 
    printk(KERN_NOTICE "Probing driver\n"); 
    switch(dev->vendor) { 
    case VENDOR://0x1708: 
     printk(KERN_NOTICE "Xilinx device found\n"); 
     break; 
    default: 
     printk(KERN_NOTICE "Device found that does not match id: id = 0x%04X\n", dev->device); 
    }; 

    int err = pci_enable_device(dev); 
    if (err) { 
     dev_err(&dev->dev, "Failed to enable FPGA PCI device (%d)\n", err); 
     goto exit; 
    } 

    err = setup_MSI_interrupt(dev, NUM_MSI); 

    if(err) 
     goto exit; 

    return 0; 

exit: 
    return -1; 
} 

static void fpga_remove(struct pci_dev *dev) 
{ 
    printk(KERN_NOTICE "REMOVING IRQ # %d\n", dev->irq); 

    free_irq(dev->irq, dev); 
    printk(KERN_NOTICE "IRQ has been freed\n"); 
    pci_disable_msi(dev);            // This causes a NUll Pointer to be dereferenced but needs to be added 
    printk(KERN_NOTICE "MSI has been disabled\n"); 
} 

static int __init fpga_init(void) 
{ 
    printk(KERN_NOTICE "Registering Driver\n"); 
    return pci_register_driver(&fpga_driver); 
    return 0; 
}

来源

2014-06-18 whh4000

你可能不应该使用在request_irq(...)的struct pci_dev作为void *dev_id参数和free_irq(...)功能。使用正确且唯一的中断参数dev_id来调用它们非常重要。这样做不会导致内核恐慌在pci_disable_msi()删除模块。

在这里阅读更多： What is dev_id parameter in request_irq?

来源

2015-04-14 12:02:34 passerby

而且不要忘记调用'pci_disable_device（）'在fpga_remove（）。 – passerby

pci_disable_msi糟糕问题

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