访问 ARM 外设寄存器：非行获取时的外部中止 (0x1008)

如何解决访问 ARM 外设寄存器：非行获取时的外部中止 (0x1008)

我是 Linux 内核驱动程序的新手，正在尝试学习。

我尝试访问集成外设的寄存器，作为测试，我只是读取了修订版 ID。 在函数“probe”中，它按预期工作，我得到了正确的值（根据处理器参考手册）。 在函数“remove”中执行完全相同的操作会生成错误：“未处理的错误：0xe0fb61dc 处的非行获取（0x1008）上的外部中止”。

你能告诉我我遗漏了什么或做错了什么吗？

感谢您的时间。

我的环境： ARM、Beaglebone Black、Linux 4.20.17-bone15

这是我的代码：

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/of_device.h>

#define QREVID     0x005C

static int module_1_probe(struct platform_device *pdev)
{
    void *pmemBase;
    u32 status = 0;

    pmemBase = memremap(pdev->resource->start,pdev->resource->end - pdev->resource->start,MEMREMAP_WT);
    status = readl(pmemBase + QREVID);
    printk(KERN_INFO "module_1_probe: QREVID = 0x%08x\n",status);
    memunmap(pmemBase);
    
    return 0 ;
}

static int module_1_remove(struct platform_device *pdev)
{
    void *pmemBase;
    u32 status = 0;

    pmemBase = memremap(pdev->resource->start,MEMREMAP_WT);
    status = readl(pmemBase + QREVID);
    printk(KERN_INFO "module_1_remove: QREVID = 0x%08x\n",status);
    memunmap(pmemBase);

    return 0 ;
}

static struct of_device_id module_1_of_match[] =
{
    { .compatible = "ti,am33xx-eqep" },{}
};
MODULE_DEVICE_TABLE(of,module_1_of_match);

static struct platform_driver module_1_driver = 
{
    .probe = module_1_probe,.remove = module_1_remove,.driver = 
    {
        .name = "module_1",.owner = THIS_MODULE,.of_match_table = module_1_of_match,},};
module_platform_driver(module_1_driver);

MODULE_LICENSE("GPL");

insmod 的结果如预期：

[  402.117788] module_1_probe: QREVID = 0x44d31103
[  402.130355] module_1_probe: QREVID = 0x44d31103
[  402.149061] module_1_probe: QREVID = 0x44d31103

rmmod 的结果：

[  415.102993] Unhandled fault: external abort on non-linefetch (0x1008) at 0xe0fb61dc
[  415.110706] pgd = 75ae9daa
[  415.113422] [e0fb61dc] *pgd=9b5d0811,*pte=48304267,*ppte=48304017
[  415.119727] Internal error: : 1008 [#1] PREEMPT THUMB2
[  415.124887] Modules linked in: module_1(O-) usb_f_acm u_serial usb_f_ecm usb_f_mass_storage usb_f_rndis u_ether libcomposite evdev spidev uio_pdrv_genirq uio ip_tables x_tables
[  415.140721] CPU: 0 PID: 2049 Comm: rmmod Tainted: G           O      4.20.17-bone15 #1
[  415.148668] Hardware name: Generic AM33XX (Flattened Device Tree)
[  415.154796] PC is at module_1_remove+0x3d/0x70 [module_1]
[  415.160233] LR is at ioremap_page_range+0xa7/0x110
[  415.165041] pc : [<bf8c10ae>]    lr : [<c089a213>]    psr: 80000033
[  415.171332] sp : d40b3ed8  ip : 00000000  fp : 00000002
[  415.176575] r10: 00000081  r9 : d40b2000  r8 : dc2eac44
[  415.181818] r7 : d40b3ed8  r6 : dc2eac10  r5 : dc52a610  r4 : bf8c1071
[  415.188371] r3 : e0fb61dc  r2 : 00000000  r1 : 48304a27  r0 : e0fb6180
[  415.194926] Flags: Nzcv  IRQs on  FIQs on  Mode SVC_32  ISA Thumb  Segment none
[  415.202264] Control: 50c5387d  Table: 94098019  DAC: 00000051
[  415.208032] Process rmmod (pid: 2049,stack limit = 0x13eca31e)
[  415.213975] Stack: (0xd40b3ed8 to 0xd40b4000)
[  415.218348] 3ec0:                                                       dc52a610 dc52a600
[  415.226562] 3ee0: 00000000 e0fb6180 40000013 bf8c319c e0fb61dc c061de0d bf8c319c c0617223
[  415.234776] 3f00: c061720d dc52a610 dc52a644 c0615f97 dc52a610 bf8c319c ffffe000 d40b3f40
[  415.242990] 3f20: 00000800 c061604f bf8c319c c0e05088 c0f16a20 c061506f bf8c3200 bf8c10f1
[  415.251204] 3f40: 00000000 c0183a1f 75646f6d 315f656c 00000000 00000000 c0e05088 db6cbb40
[  415.259417] 3f60: 00000002 00000000 db6cbb40 bee60a26 0000001d c024c6d5 db6cbb40 db6cbb40
[  415.267631] 3f80: 006cb6c0 21efe3aa 00000000 00000000 0054b1a0 0054b1a0 00000081 c0101224
[  415.275845] 3fa0: d40b2000 c0101001 00000000 0054b1a0 0054b1dc 00000800 25abd200 25abd200
[  415.284059] 3fc0: 00000000 0054b1a0 0054b1a0 00000081 bee61ae0 bee61ccc 00000001 00000002
[  415.292272] 3fe0: 004f3f5c bee61a7c 004d8d97 b6d45d68 60000030 0054b1dc 00000000 00000000
[  415.300520] [<bf8c10ae>] (module_1_remove [module_1]) from [<c0617223>] (platform_drv_remove+0x17/0x24)
[  415.309962] [<c0617223>] (platform_drv_remove) from [<c0615f97>] (device_release_driver_internal+0xf3/0x154)
[  415.319837] [<c0615f97>] (device_release_driver_internal) from [<c061604f>] (driver_detach+0x47/0x94)
[  415.329099] [<c061604f>] (driver_detach) from [<c061506f>] (bus_remove_driver+0x4f/0x90)
[  415.337228] [<c061506f>] (bus_remove_driver) from [<bf8c10f1>] (module_1_driver_exit+0x10/0xf1f [module_1])
[  415.347025] [<bf8c10f1>] (module_1_driver_exit [module_1]) from [<c0183a1f>] (sys_delete_module+0x12f/0x1c0)
[  415.356902] [<c0183a1f>] (sys_delete_module) from [<c0101001>] (ret_fast_syscall+0x1/0x62)
[  415.365198] Exception stack(0xd40b3fa8 to 0xd40b3ff0)
[  415.370271] 3fa0:                   00000000 0054b1a0 0054b1dc 00000800 25abd200 25abd200
[  415.378485] 3fc0: 00000000 0054b1a0 0054b1a0 00000081 bee61ae0 bee61ccc 00000001 00000002
[  415.386696] 3fe0: 004f3f5c bee61a7c 004d8d97 b6d45d68
[  415.391773] Code: 68fb 335c 61bb 69bb (681b) 61fb
[  415.396586] ---[ end trace ba68be8b0115d034 ]---