qemu.pdf (cmu.edu)
GDB usage — QEMU 7.0.50 documentation
搭建 Linux 内核网络调试环境（vscode + gdb + qemu） - 知乎 (zhihu.com)

一、环境

win10 + vscode + vmware + ubuntu + gdb + qemu + linux kernel。

环境	版本
win10	Windows 10 家庭中文版
vscode	1.66.2
vmware	15
ubuntu	20.04
gdb	gdb-multiarch
qemu	qemu-6.2.0

二、内核调试配置选项

1、配置

Kernel hacking  --->
    Compile-time checks and compiler options  ---> 
        [*] Compile the kernel with debug info

2、编译

make -j4

三、内核启动测试

1、启动测试

./qemu-system-arm -M vexpress-a9 -m 512M -kernel zImage -append "rdinit=/linuxrc console=ttyAMA0 loglevel=8" -dtb vexpress-v2p-ca9.dtb -nographic -net nic -net tap,ifname=tap0,script=no,downscript=no

onlylove@ubuntu:~/My/qemu/qemu-lq$ ./qemu-system-arm -M vexpress-a9 -m 512M -kernel zImage -append "rdinit=/linuxrc console=ttyAMA0 loglevel=8" -dtb vexpress-v2p-ca9.dtb -nographic -net nic -net tap,ifname=tap0,script=no,downscript=no
Booting Linux on physical CPU 0x0
Linux version 4.12.0 (onlylove@ubuntu) (gcc version 4.9.4 (Linaro GCC 4.9-2017.01) ) #2 SMP Sun May 1 23:11:31 PDT 2022
CPU: ARMv7 Processor [410fc090] revision 0 (ARMv7), cr=10c5387d
CPU: PIPT / VIPT nonaliasing data cache, VIPT nonaliasing instruction cache
OF: fdt: Machine model: V2P-CA9
Memory policy: Data cache writeback
On node 0 totalpages: 131072
free_area_init_node: node 0, pgdat 83154c00, node_mem_map 9fbfb000
  Normal zone: 1024 pages used for memmap
  Normal zone: 0 pages reserved
  Normal zone: 131072 pages, LIFO batch:31
CPU: All CPU(s) started in SVC mode.
percpu: Embedded 16 pages/cpu @9fbae000 s36352 r8192 d20992 u65536
pcpu-alloc: s36352 r8192 d20992 u65536 alloc=16*4096
pcpu-alloc: [0] 0 [0] 1 [0] 2 [0] 3 
Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 130048
Kernel command line: rdinit=/linuxrc console=ttyAMA0 loglevel=8
log_buf_len individual max cpu contribution: 4096 bytes
log_buf_len total cpu_extra contributions: 12288 bytes
log_buf_len min size: 16384 bytes
log_buf_len: 32768 bytes
early log buf free: 15004(91%)
PID hash table entries: 2048 (order: 1, 8192 bytes)
Dentry cache hash table entries: 65536 (order: 6, 262144 bytes)
Inode-cache hash table entries: 32768 (order: 5, 131072 bytes)
Memory: 469664K/524288K available (6144K kernel code, 359K rwdata, 1328K rodata, 40960K init, 170K bss, 54624K reserved, 0K cma-reserved)
Virtual kernel memory layout:
    vector  : 0xffff0000 - 0xffff1000   (   4 kB)
    fixmap  : 0xffc00000 - 0xfff00000   (3072 kB)
    vmalloc : 0xa0800000 - 0xff800000   (1520 MB)
    lowmem  : 0x80000000 - 0xa0000000   ( 512 MB)
    modules : 0x7f000000 - 0x80000000   (  16 MB)
      .text : 0x80008000 - 0x80700000   (7136 kB)
      .init : 0x80900000 - 0x83100000   (40960 kB)
      .data : 0x83100000 - 0x83159f68   ( 360 kB)
       .bss : 0x83160d24 - 0x8318b804   ( 171 kB)
SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
Hierarchical RCU implementation.
	RCU debugfs-based tracing is enabled.
	RCU restricting CPUs from NR_CPUS=8 to nr_cpu_ids=4.
RCU: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=4
NR_IRQS:16 nr_irqs:16 16
GIC CPU mask not found - kernel will fail to boot.
GIC CPU mask not found - kernel will fail to boot.
L2C: platform modifies aux control register: 0x02020000 -> 0x02420000
L2C: DT/platform modifies aux control register: 0x02020000 -> 0x02420000
L2C-310 enabling early BRESP for Cortex-A9
L2C-310 full line of zeros enabled for Cortex-A9
L2C-310 dynamic clock gating disabled, standby mode disabled
L2C-310 cache controller enabled, 8 ways, 128 kB
L2C-310: CACHE_ID 0x410000c8, AUX_CTRL 0x46420001
smp_twd: clock not found -2
sched_clock: 32 bits at 24MHz, resolution 41ns, wraps every 89478484971ns
clocksource: arm,sp804: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 1911260446275 ns
Failed to initialize '/smb@4000000/motherboard/iofpga@7,00000000/timer@12000': -22
Console: colour dummy device 80x30
Calibrating local timer... 91.60MHz.
Calibrating delay loop... 1489.30 BogoMIPS (lpj=7446528)
pid_max: default: 32768 minimum: 301
Mount-cache hash table entries: 1024 (order: 0, 4096 bytes)
Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
CPU: Testing write buffer coherency: ok
CPU0: thread -1, cpu 0, socket 0, mpidr 80000000
Setting up static identity map for 0x60100000 - 0x60100060
smp: Bringing up secondary CPUs ...
smp: Brought up 1 node, 1 CPU
SMP: Total of 1 processors activated (1489.30 BogoMIPS).
CPU: All CPU(s) started in SVC mode.
devtmpfs: initialized
VFP support v0.3: implementor 41 architecture 3 part 30 variant 9 rev 0
clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
futex hash table entries: 1024 (order: 4, 65536 bytes)
NET: Registered protocol family 16
DMA: preallocated 256 KiB pool for atomic coherent allocations
cpuidle: using governor ladder
hw-breakpoint: debug architecture 0x4 unsupported.
Serial: AMBA PL011 UART driver
OF: amba_device_add() failed (-19) for /memory-controller@100e0000
OF: amba_device_add() failed (-19) for /memory-controller@100e1000
OF: amba_device_add() failed (-19) for /watchdog@100e5000
irq: type mismatch, failed to map hwirq-75 for /interrupt-controller@1e001000!
10009000.uart: ttyAMA0 at MMIO 0x10009000 (irq = 38, base_baud = 0) is a PL011 rev1
console [ttyAMA0] enabled
1000a000.uart: ttyAMA1 at MMIO 0x1000a000 (irq = 39, base_baud = 0) is a PL011 rev1
1000b000.uart: ttyAMA2 at MMIO 0x1000b000 (irq = 40, base_baud = 0) is a PL011 rev1
1000c000.uart: ttyAMA3 at MMIO 0x1000c000 (irq = 41, base_baud = 0) is a PL011 rev1
OF: amba_device_add() failed (-19) for /smb@4000000/motherboard/iofpga@7,00000000/wdt@f000
SCSI subsystem initialized
libata version 3.00 loaded.
usbcore: registered new interface driver usbfs
usbcore: registered new interface driver hub
usbcore: registered new device driver usb
Advanced Linux Sound Architecture Driver Initialized.
clocksource: Switched to clocksource arm,sp804
NET: Registered protocol family 2
TCP established hash table entries: 4096 (order: 2, 16384 bytes)
TCP bind hash table entries: 4096 (order: 3, 32768 bytes)
TCP: Hash tables configured (established 4096 bind 4096)
UDP hash table entries: 256 (order: 1, 8192 bytes)
UDP-Lite hash table entries: 256 (order: 1, 8192 bytes)
NET: Registered protocol family 1
RPC: Registered named UNIX socket transport module.
RPC: Registered udp transport module.
RPC: Registered tcp transport module.
RPC: Registered tcp NFSv4.1 backchannel transport module.
hw perfevents: enabled with armv7_cortex_a9 PMU driver, 5 counters available
workingset: timestamp_bits=30 max_order=17 bucket_order=0
squashfs: version 4.0 (2009/01/31) Phillip Lougher
jffs2: version 2.2. (NAND) © 2001-2006 Red Hat, Inc.
9p: Installing v9fs 9p2000 file system support
io scheduler noop registered (default)
io scheduler mq-deadline registered
io scheduler kyber registered
clcd-pl11x 10020000.clcd: PL111 designer 41 rev2 at 0x10020000
clcd-pl11x 10020000.clcd: /clcd@10020000 hardware, 1024x768@59 display
Console: switching to colour frame buffer device 128x48
clcd-pl11x 1001f000.clcd: PL111 designer 41 rev2 at 0x1001f000
clcd-pl11x 1001f000.clcd: /smb@4000000/motherboard/iofpga@7,00000000/clcd@1f000 hardware, 640x480@59 display
40000000.flash: Found 2 x16 devices at 0x0 in 32-bit bank. Manufacturer ID 0x000000 Chip ID 0x000000
Intel/Sharp Extended Query Table at 0x0031
Using buffer write method
erase region 0: offset=0x0,size=0x40000,blocks=256
40000000.flash: Found 2 x16 devices at 0x0 in 32-bit bank. Manufacturer ID 0x000000 Chip ID 0x000000
Intel/Sharp Extended Query Table at 0x0031
Using buffer write method
erase region 0: offset=0x0,size=0x40000,blocks=256
Concatenating MTD devices:
(0): "40000000.flash"
(1): "40000000.flash"
into device "40000000.flash"
libphy: Fixed MDIO Bus: probed
libphy: smsc911x-mdio: probed
smsc911x 4e000000.ethernet eth0: MAC Address: 52:54:00:12:34:56
isp1760 4f000000.usb: bus width: 32, oc: digital
isp1760 4f000000.usb: NXP ISP1760 USB Host Controller
isp1760 4f000000.usb: new USB bus registered, assigned bus number 1
isp1760 4f000000.usb: Scratch test failed.
isp1760 4f000000.usb: can't setup: -19
isp1760 4f000000.usb: USB bus 1 deregistered
usbcore: registered new interface driver usb-storage
rtc-pl031 10017000.rtc: rtc core: registered pl031 as rtc0
mmci-pl18x 10005000.mmci: Got CD GPIO
mmci-pl18x 10005000.mmci: Got WP GPIO
mmci-pl18x 10005000.mmci: mmc0: PL181 manf 41 rev0 at 0x10005000 irq 34,35 (pio)
ledtrig-cpu: registered to indicate activity on CPUs
usbcore: registered new interface driver usbhid
usbhid: USB HID core driver
aaci-pl041 10004000.aaci: ARM AC'97 Interface PL041 rev0 at 0x10004000, irq 33
aaci-pl041 10004000.aaci: FIFO 512 entries
oprofile: using arm/armv7-ca9
NET: Registered protocol family 17
9pnet: Installing 9P2000 support
Registering SWP/SWPB emulation handler
input: AT Raw Set 2 keyboard as /devices/platform/smb@4000000/smb@4000000:motherboard/smb@4000000:motherboard:iofpga@7,00000000/10006000.kmi/serio0/input/input0
rtc-pl031 10017000.rtc: setting system clock to 2022-05-04 03:06:34 UTC (1651633594)
ALSA device list:
  #0: ARM AC'97 Interface PL041 rev0 at 0x10004000, irq 33
Warning: unable to open an initial console.
Freeing unused kernel memory: 40960K
input: ImExPS/2 Generic Explorer Mouse as /devices/platform/smb@4000000/smb@4000000:motherboard/smb@4000000:motherboard:iofpga@7,00000000/10007000.kmi/serio1/input/input2

Please press Enter to activate this console. 
/ # ls
bin      etc      linuxrc  proc     sbin     tmp
dev      lib      mnt      root     sys      usr
/ # 

2、调试测试

1、启动 qemu 调试环境

./qemu-system-arm -M vexpress-a9 -m 512M -kernel zImage -append "rdinit=/linuxrc console=ttyAMA0 loglevel=8" -dtb vexpress-v2p-ca9.dtb -nographic -net nic -net tap,ifname=tap0,script=no,downscript=no -S -s

# -s: 在1234端口接受GDB调试
# -S：冻结CPU直到远程GDB输入相应命令

onlylove@ubuntu:~/My/qemu/qemu-lq$ pwd
/home/onlylove/My/qemu/qemu-lq
onlylove@ubuntu:~/My/qemu/qemu-lq$ ls
arm-gdb  qemu-system-arm  u-boot  vexpress-v2p-ca9.dtb  zImage
onlylove@ubuntu:~/My/qemu/qemu-lq$ ./qemu-system-arm -M vexpress-a9 -m 512M -kernel zImage -append "rdinit=/linuxrc console=ttyAMA0 loglevel=8" -dtb vexpress-v2p-ca9.dtb -nographic -net nic -net tap,ifname=tap0,script=no,downscript=no -S -s

通过以上日志可以看到，qemu启动后等待 gdb 连接。

2、启动gdb

$ cd linux-4.12
$ gdb-multiarch vmlinux
(gdb) target remote localhost:1234
(gdb) b start_kernel
(gdb) c
(gdb) layout src

onlylove@ubuntu:~/My/linux/linux-4.12$ pwd
/home/onlylove/My/linux/linux-4.12
onlylove@ubuntu:~/My/linux/linux-4.12$ ls
arch     CREDITS        firmware  ipc      lib          modules.builtin  README    sound       virt
block    crypto         fs        Kbuild   MAINTAINERS  modules.order    samples   System.map  vmlinux
certs    Documentation  include   Kconfig  Makefile     Module.symvers   scripts   tools       vmlinux.o
COPYING  drivers        init      kernel   mm           net              security  usr
onlylove@ubuntu:~/My/linux/linux-4.12$ gdb-multiarch vmlinux
GNU gdb (Ubuntu 9.2-0ubuntu1~20.04.1) 9.2
Copyright (C) 2020 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Type "show copying" and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
    <http://www.gnu.org/software/gdb/documentation/>.

For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from vmlinux...
(gdb) target remote localhost:1234
Remote debugging using localhost:1234
0x60000000 in ?? ()
(gdb) b start_kernel
Breakpoint 1 at 0x809008e0: file init/main.c, line 493.
(gdb) c
Continuing.

Breakpoint 1, start_kernel () at init/main.c:493
493		set_task_stack_end_magic(&init_task);
(gdb) 

通过以上日志可以看到 Linux 内核停在 start_kernel 函数中。通过 layout src 可以查看源码，执行结果如下：

3、退出gdb

退出gdb调试后，linux内核正常启动，启动日志如下：

onlylove@ubuntu:~/My/qemu/qemu-lq$ pwd
/home/onlylove/My/qemu/qemu-lq
onlylove@ubuntu:~/My/qemu/qemu-lq$ ls
arm-gdb  qemu-system-arm  u-boot  vexpress-v2p-ca9.dtb  zImage
onlylove@ubuntu:~/My/qemu/qemu-lq$ ./qemu-system-arm -M vexpress-a9 -m 512M -kernel zImage -append "rdinit=/linuxrc console=ttyAMA0 loglevel=8" -dtb vexpress-v2p-ca9.dtb -nographic -net nic -net tap,ifname=tap0,script=no,downscript=no -S -s
Booting Linux on physical CPU 0x0
Linux version 4.12.0 (onlylove@ubuntu) (gcc version 4.9.4 (Linaro GCC 4.9-2017.01) ) #2 SMP Sun May 1 23:11:31 PDT 2022
CPU: ARMv7 Processor [410fc090] revision 0 (ARMv7), cr=10c5387d
CPU: PIPT / VIPT nonaliasing data cache, VIPT nonaliasing instruction cache
OF: fdt: Machine model: V2P-CA9
Memory policy: Data cache writeback
On node 0 totalpages: 131072
free_area_init_node: node 0, pgdat 83154c00, node_mem_map 9fbfb000
  Normal zone: 1024 pages used for memmap
  Normal zone: 0 pages reserved
  Normal zone: 131072 pages, LIFO batch:31
CPU: All CPU(s) started in SVC mode.
percpu: Embedded 16 pages/cpu @9fbae000 s36352 r8192 d20992 u65536
pcpu-alloc: s36352 r8192 d20992 u65536 alloc=16*4096
pcpu-alloc: [0] 0 [0] 1 [0] 2 [0] 3 
Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 130048
Kernel command line: rdinit=/linuxrc console=ttyAMA0 loglevel=8
log_buf_len individual max cpu contribution: 4096 bytes
log_buf_len total cpu_extra contributions: 12288 bytes
log_buf_len min size: 16384 bytes
log_buf_len: 32768 bytes
early log buf free: 15004(91%)
PID hash table entries: 2048 (order: 1, 8192 bytes)
Dentry cache hash table entries: 65536 (order: 6, 262144 bytes)
Inode-cache hash table entries: 32768 (order: 5, 131072 bytes)
Memory: 469664K/524288K available (6144K kernel code, 359K rwdata, 1328K rodata, 40960K init, 170K bss, 54624K reserved, 0K cma-reserved)
Virtual kernel memory layout:
    vector  : 0xffff0000 - 0xffff1000   (   4 kB)
    fixmap  : 0xffc00000 - 0xfff00000   (3072 kB)
    vmalloc : 0xa0800000 - 0xff800000   (1520 MB)
    lowmem  : 0x80000000 - 0xa0000000   ( 512 MB)
    modules : 0x7f000000 - 0x80000000   (  16 MB)
      .text : 0x80008000 - 0x80700000   (7136 kB)
      .init : 0x80900000 - 0x83100000   (40960 kB)
      .data : 0x83100000 - 0x83159f68   ( 360 kB)
       .bss : 0x83160d24 - 0x8318b804   ( 171 kB)
SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
Hierarchical RCU implementation.
	RCU debugfs-based tracing is enabled.
	RCU restricting CPUs from NR_CPUS=8 to nr_cpu_ids=4.
RCU: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=4
NR_IRQS:16 nr_irqs:16 16
GIC CPU mask not found - kernel will fail to boot.
GIC CPU mask not found - kernel will fail to boot.
L2C: platform modifies aux control register: 0x02020000 -> 0x02420000
L2C: DT/platform modifies aux control register: 0x02020000 -> 0x02420000
L2C-310 enabling early BRESP for Cortex-A9
L2C-310 full line of zeros enabled for Cortex-A9
L2C-310 dynamic clock gating disabled, standby mode disabled
L2C-310 cache controller enabled, 8 ways, 128 kB
L2C-310: CACHE_ID 0x410000c8, AUX_CTRL 0x46420001
smp_twd: clock not found -2
sched_clock: 32 bits at 24MHz, resolution 41ns, wraps every 89478484971ns
clocksource: arm,sp804: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 1911260446275 ns
Failed to initialize '/smb@4000000/motherboard/iofpga@7,00000000/timer@12000': -22
Console: colour dummy device 80x30
Calibrating local timer... 93.86MHz.
Calibrating delay loop... 1659.69 BogoMIPS (lpj=8298496)
pid_max: default: 32768 minimum: 301
Mount-cache hash table entries: 1024 (order: 0, 4096 bytes)
Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
CPU: Testing write buffer coherency: ok
CPU0: thread -1, cpu 0, socket 0, mpidr 80000000
Setting up static identity map for 0x60100000 - 0x60100060
smp: Bringing up secondary CPUs ...
smp: Brought up 1 node, 1 CPU
SMP: Total of 1 processors activated (1659.69 BogoMIPS).
CPU: All CPU(s) started in SVC mode.
devtmpfs: initialized
VFP support v0.3: implementor 41 architecture 3 part 30 variant 9 rev 0
clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
futex hash table entries: 1024 (order: 4, 65536 bytes)
NET: Registered protocol family 16
DMA: preallocated 256 KiB pool for atomic coherent allocations
cpuidle: using governor ladder
hw-breakpoint: debug architecture 0x4 unsupported.
Serial: AMBA PL011 UART driver
OF: amba_device_add() failed (-19) for /memory-controller@100e0000
OF: amba_device_add() failed (-19) for /memory-controller@100e1000
OF: amba_device_add() failed (-19) for /watchdog@100e5000
irq: type mismatch, failed to map hwirq-75 for /interrupt-controller@1e001000!
10009000.uart: ttyAMA0 at MMIO 0x10009000 (irq = 38, base_baud = 0) is a PL011 rev1
console [ttyAMA0] enabled
1000a000.uart: ttyAMA1 at MMIO 0x1000a000 (irq = 39, base_baud = 0) is a PL011 rev1
1000b000.uart: ttyAMA2 at MMIO 0x1000b000 (irq = 40, base_baud = 0) is a PL011 rev1
1000c000.uart: ttyAMA3 at MMIO 0x1000c000 (irq = 41, base_baud = 0) is a PL011 rev1
OF: amba_device_add() failed (-19) for /smb@4000000/motherboard/iofpga@7,00000000/wdt@f000
SCSI subsystem initialized
libata version 3.00 loaded.
usbcore: registered new interface driver usbfs
usbcore: registered new interface driver hub
usbcore: registered new device driver usb
Advanced Linux Sound Architecture Driver Initialized.
clocksource: Switched to clocksource arm,sp804
NET: Registered protocol family 2
TCP established hash table entries: 4096 (order: 2, 16384 bytes)
TCP bind hash table entries: 4096 (order: 3, 32768 bytes)
TCP: Hash tables configured (established 4096 bind 4096)
UDP hash table entries: 256 (order: 1, 8192 bytes)
UDP-Lite hash table entries: 256 (order: 1, 8192 bytes)
NET: Registered protocol family 1
RPC: Registered named UNIX socket transport module.
RPC: Registered udp transport module.
RPC: Registered tcp transport module.
RPC: Registered tcp NFSv4.1 backchannel transport module.
hw perfevents: enabled with armv7_cortex_a9 PMU driver, 5 counters available
workingset: timestamp_bits=30 max_order=17 bucket_order=0
squashfs: version 4.0 (2009/01/31) Phillip Lougher
jffs2: version 2.2. (NAND) © 2001-2006 Red Hat, Inc.
9p: Installing v9fs 9p2000 file system support
io scheduler noop registered (default)
io scheduler mq-deadline registered
io scheduler kyber registered
clcd-pl11x 10020000.clcd: PL111 designer 41 rev2 at 0x10020000
clcd-pl11x 10020000.clcd: /clcd@10020000 hardware, 1024x768@59 display
Console: switching to colour frame buffer device 128x48
clcd-pl11x 1001f000.clcd: PL111 designer 41 rev2 at 0x1001f000
clcd-pl11x 1001f000.clcd: /smb@4000000/motherboard/iofpga@7,00000000/clcd@1f000 hardware, 640x480@59 display
40000000.flash: Found 2 x16 devices at 0x0 in 32-bit bank. Manufacturer ID 0x000000 Chip ID 0x000000
Intel/Sharp Extended Query Table at 0x0031
Using buffer write method
erase region 0: offset=0x0,size=0x40000,blocks=256
40000000.flash: Found 2 x16 devices at 0x0 in 32-bit bank. Manufacturer ID 0x000000 Chip ID 0x000000
Intel/Sharp Extended Query Table at 0x0031
Using buffer write method
erase region 0: offset=0x0,size=0x40000,blocks=256
Concatenating MTD devices:
(0): "40000000.flash"
(1): "40000000.flash"
into device "40000000.flash"
libphy: Fixed MDIO Bus: probed
libphy: smsc911x-mdio: probed
smsc911x 4e000000.ethernet eth0: MAC Address: 52:54:00:12:34:56
isp1760 4f000000.usb: bus width: 32, oc: digital
isp1760 4f000000.usb: NXP ISP1760 USB Host Controller
isp1760 4f000000.usb: new USB bus registered, assigned bus number 1
isp1760 4f000000.usb: Scratch test failed.
isp1760 4f000000.usb: can't setup: -19
isp1760 4f000000.usb: USB bus 1 deregistered
usbcore: registered new interface driver usb-storage
rtc-pl031 10017000.rtc: rtc core: registered pl031 as rtc0
mmci-pl18x 10005000.mmci: Got CD GPIO
mmci-pl18x 10005000.mmci: Got WP GPIO
mmci-pl18x 10005000.mmci: mmc0: PL181 manf 41 rev0 at 0x10005000 irq 34,35 (pio)
ledtrig-cpu: registered to indicate activity on CPUs
usbcore: registered new interface driver usbhid
usbhid: USB HID core driver
aaci-pl041 10004000.aaci: ARM AC'97 Interface PL041 rev0 at 0x10004000, irq 33
aaci-pl041 10004000.aaci: FIFO 512 entries
oprofile: using arm/armv7-ca9
NET: Registered protocol family 17
9pnet: Installing 9P2000 support
Registering SWP/SWPB emulation handler
input: AT Raw Set 2 keyboard as /devices/platform/smb@4000000/smb@4000000:motherboard/smb@4000000:motherboard:iofpga@7,00000000/10006000.kmi/serio0/input/input0
rtc-pl031 10017000.rtc: setting system clock to 2022-05-04 03:18:21 UTC (1651634301)
ALSA device list:
  #0: ARM AC'97 Interface PL041 rev0 at 0x10004000, irq 33
Warning: unable to open an initial console.
Freeing unused kernel memory: 40960K
input: ImExPS/2 Generic Explorer Mouse as /devices/platform/smb@4000000/smb@4000000:motherboard/smb@4000000:motherboard:iofpga@7,00000000/10007000.kmi/serio1/input/input2

Please press Enter to activate this console. 
/ # ls
bin      etc      linuxrc  proc     sbin     tmp
dev      lib      mnt      root     sys      usr
/ # 

四、VSCode调试内核

1、vscode配置

安装插件清单如下：

1、Remote - SSH

2、C/C++

2、启动 qemu 调试环境

./qemu-system-arm -M vexpress-a9 -m 512M -kernel zImage -append "rdinit=/linuxrc console=ttyAMA0 loglevel=8" -dtb vexpress-v2p-ca9.dtb -nographic -net nic -net tap,ifname=tap0,script=no,downscript=no -S -s

3、启动VSCode

1、连接到ubuntu并打开Linux源码

2、配置

1、按F5进入调试，选择C++(GDB/LLDB)

特别说明：必须选中源码后，按 F5 才会弹出 C++(GDB/LLDB)。

2、选择默认配置


3、修改lanuch.json文件内容

{
    // 使用 IntelliSense 了解相关属性。 
    // 悬停以查看现有属性的描述。
    // 欲了解更多信息，请访问: https://go.microsoft.com/fwlink/?linkid=830387
    "version": "0.2.0",
    "configurations": [
        {
            "name": "(gdb) 启动",
            "type": "cppdbg",
            "request": "launch",
            "program": "/home/onlylove/My/linux/linux-4.12/vmlinux", // 指定vmlinux路径
            "args": [],
            "stopAtEntry": false,
            "cwd": "${workspaceFolder}",
            "environment": [],
            "externalConsole": false,
            "MIMode": "gdb",
            "miDebuggerPath": "/usr/bin/gdb-multiarch",	// 指定gdb-multiarch路径
            "miDebuggerServerAddress": "localhost:1234",	// gdb 连接
            "setupCommands": [
                {
                    "description": "为 gdb 启用整齐打印",
                    "text": "-enable-pretty-printing",
                    "ignoreFailures": true
                }
            ]
        }
    ]
}

4、使用vscode连接调试

在start_kernel函数打好断点，再次按F5，就可以启动调试了，调试信息如下：

5、停止调试

命令：shift + F5