Linux 内核调试 八：qemu使用initramfs文件系统

https://blog.csdn.net/song_lee/article/details/106027410

一、介绍

initramfs 即 initram file system，翻译成中文意思就是初始 ram 文件系统，基于 tmpfs，是一种大小灵活，直接作用在内存中的文件系统。initramfs 包含的工具和脚本，在正式的根文件系统的初始化脚本 init 启动之前，就被挂载。initramfs 是可选的，内核编译选项默认开启 initramfs（initrd）。以下情况下考虑使用 initramfs ：

• 加载模块，如三方驱动；
• 定制化启动系统；
• 制作一个很小的 rescue shell；
• 内核不能，但是用户态可以完成的命令；

initramfs 在内核启动的早期提供用一个户态环境，用于完成在内核启动阶段不易完成的工作。initramfs 包含的工具可以解密抽象层（用于加密的文件系统），逻辑卷管理器，软件 RAID，蓝牙驱动程序等。

一个 initramfs 至少包含一个文件，即 /init，内核将这个文件执行起来的进程设置为 main init 进程，pid = 1。内核挂载 initramfs 时，文件系统的根分区并没有挂载，所以无法访问文件系统中的文件。大多数嵌入式设备可能需要一个 shell，那么也会在 initramfs 打包进一个 shell。如果还需要其他工具或者脚本，也可以打包进 initramfs，但注意，必须包含依赖，因为 initramfs 是一个能够独立运行的 ram 文件系统。

二、配置内核

1、解压内核

onlylove@ubuntu:~/My/linux$ ls
linux-4.12.tar.gz
onlylove@ubuntu:~/My/linux$ tar -zxf linux-4.12.tar.gz 
onlylove@ubuntu:~/My/linux$ ls
linux-4.12  linux-4.12.tar.gz
onlylove@ubuntu:~/My/linux$

2、设置编译工具链和平台架构

1、修改前

ARCH		?= $(SUBARCH)
CROSS_COMPILE	?= $(CONFIG_CROSS_COMPILE:"%"=%)

2、修改后

ARCH		?= arm
CROSS_COMPILE	?= /home/onlylove/My/gcc/gcc-linaro-4.9.4-2017.01/bin/arm-linux-gnueabihf-

3、设置vexpress_defconfig默认配置

onlylove@ubuntu:~/My/linux/linux-4.12$ ls
arch   COPYING  Documentation  fs       ipc      kernel       Makefile  README   security  usr
block  CREDITS  drivers        include  Kbuild   lib          mm        samples  sound     virt
certs  crypto   firmware       init     Kconfig  MAINTAINERS  net       scripts  tools
onlylove@ubuntu:~/My/linux/linux-4.12$ make vexpress_defconfig
#
# configuration written to .config
#
onlylove@ubuntu:~/My/linux/linux-4.12$ make distclean
  CLEAN   scripts/basic
  CLEAN   scripts/kconfig
  CLEAN   .config
onlylove@ubuntu:~/My/linux/linux-4.12$ clear
onlylove@ubuntu:~/My/linux/linux-4.12$ 
onlylove@ubuntu:~/My/linux/linux-4.12$ 
onlylove@ubuntu:~/My/linux/linux-4.12$ 
onlylove@ubuntu:~/My/linux/linux-4.12$ 
onlylove@ubuntu:~/My/linux/linux-4.12$ 
onlylove@ubuntu:~/My/linux/linux-4.12$ ls
arch   COPYING  Documentation  fs       ipc      kernel       Makefile  README   security  usr
block  CREDITS  drivers        include  Kbuild   lib          mm        samples  sound     virt
certs  crypto   firmware       init     Kconfig  MAINTAINERS  net       scripts  tools
onlylove@ubuntu:~/My/linux/linux-4.12$ make vexpress_defconfig
  HOSTCC  scripts/basic/fixdep
  HOSTCC  scripts/kconfig/conf.o
  SHIPPED scripts/kconfig/zconf.tab.c
  SHIPPED scripts/kconfig/zconf.lex.c
  SHIPPED scripts/kconfig/zconf.hash.c
  HOSTCC  scripts/kconfig/zconf.tab.o
In file included from scripts/kconfig/zconf.tab.c:2468:
scripts/kconfig/confdata.c: In function ‘conf_write’:
scripts/kconfig/confdata.c:773:19: warning: ‘%s’ directive writing likely 7 or more bytes into a region of size between 1 and 4097 [-Wformat-overflow=]
  773 |  sprintf(newname, "%s%s", dirname, basename);
      |                   ^~~~~~
scripts/kconfig/confdata.c:773:19: note: assuming directive output of 7 bytes
In file included from /usr/include/stdio.h:867,
                 from scripts/kconfig/zconf.tab.c:82:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:36:10: note: ‘__builtin___sprintf_chk’ output 1 or more bytes (assuming 4104) into a destination of size 4097
   36 |   return __builtin___sprintf_chk (__s, __USE_FORTIFY_LEVEL - 1,
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   37 |       __bos (__s), __fmt, __va_arg_pack ());
      |       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from scripts/kconfig/zconf.tab.c:2468:
scripts/kconfig/confdata.c:776:20: warning: ‘.tmpconfig.’ directive writing 11 bytes into a region of size between 1 and 4097 [-Wformat-overflow=]
  776 |   sprintf(tmpname, "%s.tmpconfig.%d", dirname, (int)getpid());
      |                    ^~~~~~~~~~~~~~~~~
In file included from /usr/include/stdio.h:867,
                 from scripts/kconfig/zconf.tab.c:82:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:36:10: note: ‘__builtin___sprintf_chk’ output between 13 and 4119 bytes into a destination of size 4097
   36 |   return __builtin___sprintf_chk (__s, __USE_FORTIFY_LEVEL - 1,
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   37 |       __bos (__s), __fmt, __va_arg_pack ());
      |       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  HOSTLD  scripts/kconfig/conf
#
# configuration written to .config
#
onlylove@ubuntu:~/My/linux/linux-4.12$ 

4、内核编译

make -j4

5、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$ 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
Booting Linux on physical CPU 0x0
Linux version 4.12.0 (onlylove@ubuntu) (gcc version 4.9.4 (Linaro GCC 4.9-2017.01) ) #1 SMP Sun May 1 22:47:37 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 80a54c00, 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: 509600K/524288K available (6144K kernel code, 359K rwdata, 1328K rodata, 1024K init, 170K bss, 14688K 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 - 0x80a00000   (1024 kB)
      .data : 0x80a00000 - 0x80a59f68   ( 360 kB)
       .bss : 0x80a60d24 - 0x80a8b804   ( 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... 93.73MHz.
Calibrating delay loop... 1640.03 BogoMIPS (lpj=8200192)
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 (1640.03 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 2022-05-02 05:57:03 UTC (1651471023)
ALSA device list:
  #0: ARM AC'97 Interface PL041 rev0 at 0x10004000, irq 33
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
VFS: Cannot open root device "(null)" or unknown-block(0,0): error -6
Please append a correct "root=" boot option; here are the available partitions:
1f00          131072 mtdblock0 
 (driver?)
1f01           32768 mtdblock1 
 (driver?)
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.12.0 #1
Hardware name: ARM-Versatile Express
[<8010f398>] (unwind_backtrace) from [<8010b878>] (show_stack+0x10/0x14)
[<8010b878>] (show_stack) from [<803b28a4>] (dump_stack+0x94/0xa8)
[<803b28a4>] (dump_stack) from [<801d543c>] (panic+0xdc/0x254)
[<801d543c>] (panic) from [<8090123c>] (mount_block_root+0x1c0/0x294)
[<8090123c>] (mount_block_root) from [<8090142c>] (mount_root+0x11c/0x124)
[<8090142c>] (mount_root) from [<8090158c>] (prepare_namespace+0x158/0x19c)
[<8090158c>] (prepare_namespace) from [<80900ed8>] (kernel_init_freeable+0x270/0x280)
[<80900ed8>] (kernel_init_freeable) from [<80658e14>] (kernel_init+0x8/0x110)
[<80658e14>] (kernel_init) from [<80107678>] (ret_from_fork+0x14/0x3c)
---[ end Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)

说明：启动失败。

三、修改配置

1、添加内核支持

General setup  --->
	[*] Initial RAM filesystem and RAM disk (initramfs/initrd) support
	()    Initramfs source file(s)

特别说明：通过这种方法，将文件系统编译到内核中，如果需要修改文件系统，需要重新编译内核。

2、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... 92.16MHz.
Calibrating delay loop... 1443.43 BogoMIPS (lpj=7217152)
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 (1443.43 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 2022-05-02 06:15:27 UTC (1651472127)
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
/ #