debian內核代碼執行流程(三）

時間 2019-12-10

標籤 debian 內核代碼執行流程简体版

原文原文鏈接

下面這行輸出信息是啓動udevd進程產生的輸出信息：linux

[    3.306217] udevd[49]: starting version 175

175是udevd的版本號。ios

根據《essential linux device drivers》中關於udev的說明（英文書140頁），設備能夠分紅熱插拔和冷插拔。git

熱插拔是在已經運行的系統中鏈接的設備，冷插拔是系統啓動前插入的設備。併發

當系統檢測到熱插拔設備時，系統使用netlink socket向用戶空間發送uevents。異步

在用戶端，udev管理設備的建立和刪除、接收uevent,管理熱插拔設備。udev也能夠處理冷插拔。由於udev是用戶程序，只能在內核驅動後纔開始執行，須要特殊的機制來模擬熱插拔時間。socket

在啓動時，內核在sysfs下爲全部設備建立名爲uevent的文件，而後向這些文件發送冷插拔時間。async

當udev啓動後，它會從sysfs中讀取uevent，爲每一個冷插拔設備產生熱插拔時間。函數

此時加載r8169.ko模塊，執行r8169.ko模塊的初始化函數，即rtl8169_init_module（drivers/net/ethernet/realtek/r8169.c）.post

以後調用rtl8169_pci_driver.probe函數，即rtl8169_init_one，rtl8169_init_one中輸出下面信息：

[    3.346446] r8169 Gigabit Ethernet driver 2.3LK-NAPI loaded

rtl8169_init_one中調用pci_set_master,pci_set_master調用pcibios_set_master,輸出下面信息：

[    2.854355] pcieport 0000:00:1c.0: setting latency timer to 64

下面信息是由setup_msi_irq輸出的（但不知道是從哪一個函數調用過去的）：

[    2.854395] pcieport 0000:00:1c.0: irq 40 for MSI/MSI-X

rtl8169_init_one中繼續輸出下面信息：

[    3.346995] r8169 0000:04:00.0: eth0: RTL8102e at 0xf821a000, 00:e0:4c:26:51:75, XID 14c00000 IRQ 44

接着加載scsi模塊，執行init_scsi，輸出下面信息：

[    3.372657] SCSI subsystem initialized

接着加載usbcore模塊，執行usb_init(drivers/usb/core/usb.c),usb_init調用usb_register(&usbfs_driver),輸出下面信息：

[    3.384633] usbcore: registered new interface driver usbfs

usb_init調用usb_hub_init,usb_hub_init調用usb_register(&hub_driver),輸出下面信息：

[    3.384665] usbcore: registered new interface driver hub

usb_hub_init中還建立了khubd線程，線程執行函數是hub_thread,用於監控hub狀態變動。

usb_init中接着調用usb_register_device_driver(&usb_generic_driver,THIS_MODULE),輸出下面信息：

[    3.384694] usbcore: registered new device driver usb

接着加載ehci-hcd模塊，執行ehci_hcd_init（drivers/usb/host/ehci-hcd.c)，輸出下面信息：

[    3.385735] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver

ehci_hcd_init調用pci_register_driver(&PCI_DRIVER),而PCI_DRIVER即ehci_pci_driver.

以後會調用ehci_pci_driver.probe，即usb_hcd_pci_probe函數。

usb_hcd_pci_probe調用pci_set_master, pci_set_master調用pcibios_set_master,輸出下面信息:

[    3.385794] ehci_hcd 0000:00:1d.7: setting latency timer to 64

usb_hcd_pci_probe接着調用usb_add_hcd，輸出下面信息：

[    3.385798] ehci_hcd 0000:00:1d.7: EHCI Host Controller

usb_add_hcd調用usb_register_bus,輸出下面信息：

[    3.385826] ehci_hcd 0000:00:1d.7: new USB bus registered, assigned bus number 1

usb_add_hcd調用hcd->driver->reset,即ehci_pci_hc_driver->reset,也即ehci_pci_setup,echi_pci_setup中輸出下面信息：

[    3.385849] ehci_hcd 0000:00:1d.7: using broken periodic workaround
[    3.385859] ehci_hcd 0000:00:1d.7: debug port 1

ehci_pci_setup調用echi_pci_reinit,ehci_pci_reinit調用pci_set_mwi,pci_set_mwi調用pci_set_cacheline_size, 輸出下面信息：

[    3.389747] ehci_hcd 0000:00:1d.7: cache line size of 32 is not supported

usb_add_hcd調用usb_hcd_request_irqs,輸出下面信息：

[    3.408370] ehci_hcd 0000:00:1d.7: irq 23, io mem 0xfdfff000

接着加載libata.ko模塊，調用ata_init,輸出下面信息：

[    3.412309] libata version 3.00 loaded.

接着加載uhci-hcd.ko模塊，調用uhci_hcd_init,輸出下面信息：

[    3.412721] uhci_hcd: USB Universal Host Controller Interface driver

接着加載floppy.ko模塊，調用floppy_module_init, floppy_module_init調用floppy_init,floppy_init調用get_fdc_version,輸出下面信息：

[    3.423746] FDC 0 is a post-1991 82077

上面ehci-hcd模塊中usb_add_hcd調用hcd->driver->start，即ehci_pci_hc_driver->start,即ehci_run函數，輸出下面信息：

[    3.424024] ehci_hcd 0000:00:1d.7: USB 2.0 started, EHCI 1.00

因而可知，模塊加載多是併發執行的。

usb_add_hcd中接着調用register_root_hub,register_root_hub調用usb_new_device,usb_new_device調用annouce_device,輸出下面信息：

[    3.424090] usb usb1: New USB device found, idVendor=1d6b, idProduct=0002
[    3.424095] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[    3.424100] usb usb1: Product: EHCI Host Controller
[    3.424104] usb usb1: Manufacturer: Linux 3.2.57 ehci_hcd
[    3.424107] usb usb1: SerialNumber: 0000:00:1d.7

調用hub_probe（不知道從哪兒開始調用的），輸出下面信息：

[    3.424288] hub 1-0:1.0: USB hub found

hub_probe調用hub_configure,輸出下面信息：

[    3.424294] hub 1-0:1.0: 8 ports detected

上面uhci_hcd_init調用pci_register_driver(&PCI_DRIVER),而PCI_DRIVER即uhci_pci_driver,

以後調用uhci_pci_driver.probe,即usb_hcd_pci_probe函數，跟前面ehci的例子相似輸出下面信息：

[    3.425261] uhci_hcd 0000:00:1d.0: setting latency timer to 64
[    3.425267] uhci_hcd 0000:00:1d.0: UHCI Host Controller
[    3.425283] uhci_hcd 0000:00:1d.0: new USB bus registered, assigned bus number 2
[    3.425315] uhci_hcd 0000:00:1d.0: irq 23, io base 0x0000fe00
[    3.425351] usb usb2: New USB device found, idVendor=1d6b, idProduct=0001
[    3.425353] usb usb2: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[    3.425355] usb usb2: Product: UHCI Host Controller
[    3.425357] usb usb2: Manufacturer: Linux 3.2.57 uhci_hcd
[    3.425359] usb usb2: SerialNumber: 0000:00:1d.0
[    3.425647] hub 2-0:1.0: USB hub found
[    3.425653] hub 2-0:1.0: 2 ports detected
[    3.425743] uhci_hcd 0000:00:1d.1: setting latency timer to 64
[    3.425746] uhci_hcd 0000:00:1d.1: UHCI Host Controller
[    3.425753] uhci_hcd 0000:00:1d.1: new USB bus registered, assigned bus number 3
[    3.425790] uhci_hcd 0000:00:1d.1: irq 19, io base 0x0000fd00
[    3.425824] usb usb3: New USB device found, idVendor=1d6b, idProduct=0001
[    3.425826] usb usb3: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[    3.425828] usb usb3: Product: UHCI Host Controller
[    3.425830] usb usb3: Manufacturer: Linux 3.2.57 uhci_hcd
[    3.425832] usb usb3: SerialNumber: 0000:00:1d.1
[    3.425938] hub 3-0:1.0: USB hub found
[    3.425942] hub 3-0:1.0: 2 ports detected
[    3.426010] uhci_hcd 0000:00:1d.2: setting latency timer to 64
[    3.426014] uhci_hcd 0000:00:1d.2: UHCI Host Controller
[    3.426020] uhci_hcd 0000:00:1d.2: new USB bus registered, assigned bus number 4
[    3.426051] uhci_hcd 0000:00:1d.2: irq 18, io base 0x0000fc00
[    3.426082] usb usb4: New USB device found, idVendor=1d6b, idProduct=0001
[    3.426085] usb usb4: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[    3.426087] usb usb4: Product: UHCI Host Controller
[    3.426089] usb usb4: Manufacturer: Linux 3.2.57 uhci_hcd
[    3.426091] usb usb4: SerialNumber: 0000:00:1d.2
[    3.426198] hub 4-0:1.0: USB hub found
[    3.426202] hub 4-0:1.0: 2 ports detected
[    3.426273] uhci_hcd 0000:00:1d.3: setting latency timer to 64
[    3.426276] uhci_hcd 0000:00:1d.3: UHCI Host Controller
[    3.426283] uhci_hcd 0000:00:1d.3: new USB bus registered, assigned bus number 5
[    3.426314] uhci_hcd 0000:00:1d.3: irq 16, io base 0x0000fb00
[    3.426344] usb usb5: New USB device found, idVendor=1d6b, idProduct=0001
[    3.426347] usb usb5: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[    3.426349] usb usb5: Product: UHCI Host Controller
[    3.426351] usb usb5: Manufacturer: Linux 3.2.57 uhci_hcd
[    3.426353] usb usb5: SerialNumber: 0000:00:1d.3
[    3.426454] hub 5-0:1.0: USB hub found
[    3.426457] hub 5-0:1.0: 2 ports detected

由於當前系統上有多個uhci hcd controller，對每一個uhci hcd controller都有相應的輸出信息。

在當前系統上能夠列出全部的hcd controller信息：

$ tree /sys/bus/usb/devices
/sys/bus/usb/devices
├── 1-0:1.0 -> ../../../devices/pci0000:00/0000:00:1d.7/usb1/1-0:1.0
├── 1-1 -> ../../../devices/pci0000:00/0000:00:1d.7/usb1/1-1
├── 1-1:1.0 -> ../../../devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1:1.0
├── 1-1.2 -> ../../../devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.2
├── 1-1.2:1.0 -> ../../../devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.2/1-1.2:1.0
├── 1-1.2:1.1 -> ../../../devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.2/1-1.2:1.1
├── 1-4 -> ../../../devices/pci0000:00/0000:00:1d.7/usb1/1-4
├── 1-4:1.0 -> ../../../devices/pci0000:00/0000:00:1d.7/usb1/1-4/1-4:1.0
├── 2-0:1.0 -> ../../../devices/pci0000:00/0000:00:1d.0/usb2/2-0:1.0
├── 2-2 -> ../../../devices/pci0000:00/0000:00:1d.0/usb2/2-2
├── 2-2:1.0 -> ../../../devices/pci0000:00/0000:00:1d.0/usb2/2-2/2-2:1.0
├── 3-0:1.0 -> ../../../devices/pci0000:00/0000:00:1d.1/usb3/3-0:1.0
├── 3-1 -> ../../../devices/pci0000:00/0000:00:1d.1/usb3/3-1
├── 3-1:1.0 -> ../../../devices/pci0000:00/0000:00:1d.1/usb3/3-1/3-1:1.0
├── 4-0:1.0 -> ../../../devices/pci0000:00/0000:00:1d.2/usb4/4-0:1.0
├── 5-0:1.0 -> ../../../devices/pci0000:00/0000:00:1d.3/usb5/5-0:1.0
├── usb1 -> ../../../devices/pci0000:00/0000:00:1d.7/usb1
├── usb2 -> ../../../devices/pci0000:00/0000:00:1d.0/usb2
├── usb3 -> ../../../devices/pci0000:00/0000:00:1d.1/usb3
├── usb4 -> ../../../devices/pci0000:00/0000:00:1d.2/usb4
└── usb5 -> ../../../devices/pci0000:00/0000:00:1d.3/usb5

加載ata-piix.ko模塊，調用piix_init,piix_init調用pci_register_driver(&piix_pci_driver),以後調用piix_pci_driver.probe,即piix_init_one。

輸出下面信息：

[    3.426522] ata_piix 0000:00:1f.1: version 2.13

piix_init_one調用pci_set_master,pci_set_master調用pcibios_set_master,pcibios_set_master調用, 輸出下面信息：

[    3.426578] ata_piix 0000:00:1f.1: setting latency timer to 64

piix_init_one調用ata_pci_sff_activate_host,ata_pci_sff_activate_host調用ata_host_register,ata_host_register調用ata_scsi_add_hosts,

ata_scsi_add_hosts對每一個port調用scsi_add_host,scsi_add_host調用scsi_add_host_with_dma,輸出下面信息（由於屢次調用，因此多行輸出）：

[    3.427370] scsi0 : ata_piix
[    3.427473] scsi1 : ata_piix

ata_host_register中對每一個port輸出信息，獲得以下內容：

[    3.427936] ata1: PATA max UDMA/100 cmd 0x1f0 ctl 0x3f6 bmdma 0xfa00 irq 14
[    3.427939] ata2: PATA max UDMA/100 cmd 0x170 ctl 0x376 bmdma 0xfa08 irq 15

接着對於新的IDE controller，調用piix_pci_driver.probe,即piix_init_one。

piinx_init_one調用piix_init_sata_map,輸出下面信息：

[    3.427974] ata_piix 0000:00:1f.2: MAP [ P0 P2 P1 P3 ]

piix_init_one調用pci_set_master,pci_set_master調用pcibios_set_master,pcibios_set_master調用, 輸出下面信息：

[    3.426578] ata_piix 0000:00:1f.1: setting latency timer to 64

下面一行輸出是ata2的錯誤信息（懶得分析是從哪兒產生的）：

[    3.428496] ata2: port disabled--ignoring

與前面相似，還有下面的輸出：

[    3.428513] scsi2 : ata_piix
[    3.428907] scsi3 : ata_piix
[    3.429356] ata3: SATA max UDMA/133 cmd 0xf900 ctl 0xf800 bmdma 0xf500 irq 19
[    3.429359] ata4: SATA max UDMA/133 cmd 0xf700 ctl 0xf600 bmdma 0xf508 irq 19

ata_host_register對每一個port調用async_schedule異步執行async_port_probe.

async_port_probe調用ata_port_probe,ata_port_probe調用ata_bus_probe,ata_bus_probe對總線上設備調用ata_dev_configure.

[    3.600351] ata3.00: ATA-8: ST3250318AS, CC38, max UDMA/133
[    3.600358] ata3.00: 488397168 sectors, multi 16: LBA48 NCQ (depth 0/32)

ata_bus_probe調用ata_set_mode,ata_set_mode 調用ata_do_set_mode,ata_do_set_mode調用ata_dev_set_mode，輸出下面信息：

[    3.616337] ata3.00: configured for UDMA/133

前面提到過，在usbcore剛掛載時，建立了一個khubd內核線程，用於檢查hub的狀態並執行相應的功能,線程執行函數是hub_thread.

hub_thread中調用hub_events, hub_events調用hub_port_init,輸出下面信息：

[    3.736020] usb 1-1: new high-speed USB device number 2 using ehci_hcd

對ata1仍然也有調用async_schedule,雖然它先被調用，可是卻執行比ata3還晚，輸出下面信息：

[    3.760302] ata1.01: ATAPI: ATAPI   iHDP118   4, GL05, max UDMA/33
[    3.776191] ata1.01: configured for UDMA/33

下面兩行不知道是哪一個函數調用scsi_add_lun產生的：

[    3.778163] scsi 0:0:1:0: CD-ROM            ATAPI    iHDP118   4      GL05 PQ: 0 ANSI: 5
[    3.778453] scsi 2:0:0:0: Direct-Access     ATA      ST3250318AS      CC38 PQ: 0 ANSI: 5

此時檢測到硬盤，會調用sd_probe.sd_probe調用async_schedule異步調用sd_probe_async,sd_probe_async調用sd_revalidate_disk,

sd_revalidate_disk調用sd_read_capacity,輸出下面信息：

[    3.783064] sd 2:0:0:0: [sda] 488397168 512-byte logical blocks: (250 GB/232 GiB)

sd_revalidate_disk調用sd_read_write_protect_flag,輸出下面信息：

[    3.783126] sd 2:0:0:0: [sda] Write Protect is off
[    3.783128] sd 2:0:0:0: [sda] Mode Sense: 00 3a 00 00

sd_revalidate_disk調用sd_read_cache_type,輸出下面信息：

[    3.783148] sd 2:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA

此時檢測到光驅，調用sr_probe,sr_probe調用get_capabilites,輸出下面信息：

[    3.785910] sr0: scsi3-mmc drive: 48x/48x cd/rw xa/form2 cdda tray

sr_probe調用register_cdrom，輸出下面信息：

[    3.785915] cdrom: Uniform CD-ROM driver Revision: 3.20

sr_probe中輸出下面信息：

[    3.786106] sr 0:0:1:0: Attached scsi CD-ROM sr0

下面兩行輸出不知道是從哪一個地方調用過去的。

tsc_refine_calibration_work中產生下面輸出：

[    3.836020] Refined TSC clocksource calibration: 2510.403 MHz.

clocksource_select中產生下面輸出：

[    3.836028] Switching to clocksource tsc

下面一行輸出信息不知道是如何產生的（應該是在sd_probe_async中產生的？）：

[    3.842587]  sda: sda1 sda2 < sda5 sda6 sda7 sda8 > sda3

sd_probe_async中輸出下面信息：

[    3.843109] sd 2:0:0:0: [sda] Attached SCSI disk

下面兩行信息是從sg_add函數產生的（但不知道是從哪一個地方調用過去的）：

[    3.845469] sr 0:0:1:0: Attached scsi generic sg0 type 5
[    3.845545] sd 2:0:0:0: Attached scsi generic sg1 type 0

下面的輸出信息和前面相似（khubd檢測並輸出信息）：

[    3.868682] usb 1-1: New USB device found, idVendor=1a40, idProduct=0101
[    3.868685] usb 1-1: New USB device strings: Mfr=0, Product=1, SerialNumber=0
[    3.868687] usb 1-1: Product: USB 2.0 Hub
[    3.868967] hub 1-1:1.0: USB hub found
[    3.869062] hub 1-1:1.0: 4 ports detected
[    4.092020] usb 1-4: new high-speed USB device number 5 using ehci_hcd
[    4.224322] usb 1-4: New USB device found, idVendor=0b1e, idProduct=0006
[    4.224328] usb 1-4: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[    4.464020] usb 2-2: new low-speed USB device number 2 using uhci_hcd

接着三行信息是電源管理模塊相關：

[    4.633397] PM: Starting manual resume from disk
[    4.633400] PM: Hibernation image partition 8:8 present
[    4.633401] PM: Looking for hibernation image.

檢測到羅技光電鼠標：

[    4.639360] usb 2-2: New USB device found, idVendor=046d, idProduct=c05a
[    4.639365] usb 2-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[    4.639370] usb 2-2: Product: USB Optical Mouse
[    4.639373] usb 2-2: Manufacturer: Logitech