用Qemu模拟vexpress-a9 （五） --- u-boot引导kernel，device tree的使用
环境介绍
Win7 64 + Vmware 11 + ubuntu14.04 32
u-boot 版本：u-boot-2015-04
Linux kernel版本：linux-3.16.y
busybox版本：1_24_stable
交叉编译工具链：arm-linux-gnueabi-
qemu版本：stable-2.4
目的
本博文的目的是使用设备树来启动内核，这里有两种设备树传参方案，第一种是用u-boot，第二种是直接用Qemu启动kernel，然后在Qemu的命令行参数中利用-dtb将设备树文件传递过去。
关于设备树可以参考一下：http://www.cnblogs.com/pengdonglin137/p/4495056.html
步骤
1、配置u-boot
vexpress-a9的u-boot默认已经支持设备树了。
2、配置内核
vexpress-a9的kernel默认也已经支持了。
3、编译设备树
在内核源码根目录下执行如下命令：
make CROSS_COMPILE=arm-linux-gnueabi- ARCH=arm O=./out_vexpress_3_16 dtbs
然后会在out_vexpress_3_16/arch/arm/boot/dts/下生产如下几个文件
vexpress-v2p-ca15_a7.dtb vexpress-v2p-ca15-tc1.dtb vexpress-v2p-ca5s.dtb vexpress-v2p-ca9.dtb
这里我们用vexpress-v2p-ca9.dtb，然后将其拷贝到/tftpboot下面
cp out_vexpress_3_16/arch/arm/boot/dts/vexpress-v2p-ca9.dtb /tftpboot/dtb
4、测试
执行如下命令
qemu-system-arm -M vexpress-a9 \
-kernel /root/tq2440_work/u-boot/u-boot/u-boot \
-nographic \
-m 512M \
-net nic,vlan= -net tap,vlan=,ifname=tap0 \
-sd /root/tq2440_work/busybox_study/a9rootfs.ext3
然后进入u-boot命令行模式，执行如下命令
setenv bootargs 'root=/dev/mmcblk0 console=ttyAMA0'
tftp 0x60003000 uImage
tftp 0x60500000 dtb
bootm 0x60003000 - 0x60500000
下面是启动信息：
U-Boot 2015.07-rc3--gf3edfd3-dirty (Dec - :: -) DRAM: MiB
WARNING: Caches not enabled
Flash: MiB
MMC: MMC:
*** Warning - bad CRC, using default environment In: serial
Out: serial
Err: serial
Net: smc911x-
Warning: smc911x- using MAC address from net device Hit any key to stop autoboot:
VExpress# setenv bootargs 'root=/dev/mmcblk0 console=ttyAMA0'
VExpress# tftp 0x60003000 uImage
smc911x: MAC :::::
smc911x: detected LAN9118 controller
smc911x: phy initialized
smc911x: MAC :::::
Using smc911x- device
TFTP from server 192.168.11.20; our IP address is 192.168.11.5
Filename 'uImage'.
Load address: 0x60003000
Loading: #################################################################
#################################################################
#################################################################
################################
698.2 KiB/s
done
Bytes transferred = (32cd30 hex)
smc911x: MAC :::::
VExpress# tftp 0x60500000 dtb
smc911x: MAC :::::
smc911x: detected LAN9118 controller
smc911x: phy initialized
smc911x: MAC :::::
Using smc911x- device
TFTP from server 192.168.11.20; our IP address is 192.168.11.5
Filename 'dtb'.
Load address: 0x60500000
Loading: #
971.7 KiB/s
done
Bytes transferred = (328d hex)
smc911x: MAC :::::
VExpress# bootm 0x60003000 - 0x60500000
## Booting kernel from Legacy Image at ...
Image Name: Linux-3.16.
Image Type: ARM Linux Kernel Image (uncompressed)
Data Size: Bytes = 3.2 MiB
Load Address:
Entry Point:
Verifying Checksum ... OK
## Flattened Device Tree blob at
Booting using the fdt blob at 0x60500000
Loading Kernel Image ... OK
Loading Device Tree to 7fee2000, end 7fee828c ... OK Starting kernel ... Booting Linux on physical CPU 0x0
Initializing cgroup subsys cpuset
Linux version 3.16. (root@ubuntu) (gcc version 4.7. (Ubuntu/Linaro 4.7.-12ubuntu1) ) # SMP Sun Dec :: PST
CPU: ARMv7 Processor [410fc090] revision (ARMv7), cr=10c53c7d
CPU: PIPT / VIPT nonaliasing data cache, VIPT nonaliasing instruction cache
Machine model: V2P-CA9
Memory policy: Data cache writeback
CPU: All CPU(s) started in SVC mode.
PERCPU: Embedded pages/cpu @9ffcf000 s7552 r8192 d12928 u32768
Built zonelists in Zone order, mobility grouping on. Total pages:
Kernel command line: root=/dev/mmcblk0 console=ttyAMA0
PID hash table entries: (order: , bytes)
Dentry cache hash table entries: (order: , bytes)
Inode-cache hash table entries: (order: , bytes)
Memory: 513148K/524288K available (4567K kernel code, 191K rwdata, 1292K rodata, 239K init, 149K bss, 11140K reserved)
Virtual kernel memory layout:
vector : 0xffff0000 - 0xffff1000 ( kB)
fixmap : 0xffc00000 - 0xffe00000 ( kB)
vmalloc : 0xa0800000 - 0xff000000 ( MB)
lowmem : 0x80000000 - 0xa0000000 ( MB)
modules : 0x7f000000 - 0x80000000 ( MB)
.text : 0x80008000 - 0x805c1238 ( kB)
.init : 0x805c2000 - 0x805fdd80 ( kB)
.data : 0x805fe000 - 0x8062dc20 ( kB)
.bss : 0x8062dc28 - 0x806533ec ( kB)
SLUB: HWalign=, Order=-, MinObjects=, CPUs=, Nodes=
Hierarchical RCU implementation.
RCU restricting CPUs from NR_CPUS= to nr_cpu_ids=.
RCU: Adjusting geometry for rcu_fanout_leaf=, nr_cpu_ids=
NR_IRQS: nr_irqs:
GIC CPU mask not found - kernel will fail to boot.
GIC CPU mask not found - kernel will fail to boot.
sched_clock: bits at 24MHz, resolution 41ns, wraps every 178956969942ns
Console: colour dummy device 80x30
Calibrating delay loop... 398.13 BogoMIPS (lpj=)
pid_max: default: minimum:
Mount-cache hash table entries: (order: , bytes)
Mountpoint-cache hash table entries: (order: , bytes)
CPU: Testing write buffer coherency: ok
CPU0: thread -, cpu , socket , mpidr
Setting up static identity map for 0x60455850 - 0x604558a8
CPU1: failed to boot: -
CPU2: failed to boot: -
CPU3: failed to boot: -
Brought up CPUs
SMP: Total of processors activated.
CPU: All CPU(s) started in SVC mode.
devtmpfs: initialized
VFP support v0.: implementor architecture part variant rev
regulator-dummy: no parameters
NET: Registered protocol family
DMA: preallocated KiB pool for atomic coherent allocations
cpuidle: using governor ladder
cpuidle: using governor menu
of_amba_device_create(): amba_device_add() failed (-) for /memory-controller@100e0000
of_amba_device_create(): amba_device_add() failed (-) for /memory-controller@100e1000
of_amba_device_create(): amba_device_add() failed (-) for /watchdog@100e5000
of_amba_device_create(): amba_device_add() failed (-) for /smb/motherboard/iofpga@,/sysctl@
of_amba_device_create(): amba_device_add() failed (-) for /smb/motherboard/iofpga@,/wdt@0f000
hw-breakpoint: debug architecture 0x4 unsupported.
Serial: AMBA PL011 UART driver
.uart: ttyAMA0 at MMIO 0x10009000 (irq = , base_baud = ) is a PL011 rev1
console [ttyAMA0] enabled
1000a000.uart: ttyAMA1 at MMIO 0x1000a000 (irq = , base_baud = ) is a PL011 rev1
1000b000.uart: ttyAMA2 at MMIO 0x1000b000 (irq = , base_baud = ) is a PL011 rev1
1000c000.uart: ttyAMA3 at MMIO 0x1000c000 (irq = , base_baud = ) is a PL011 rev1
3V3: mV
SCSI subsystem initialized
usbcore: registered new interface driver usbfs
usbcore: registered new interface driver hub
usbcore: registered new device driver usb
Advanced Linux Sound Architecture Driver Initialized.
Switched to clocksource arm,sp804
NET: Registered protocol family
TCP established hash table entries: (order: , bytes)
TCP bind hash table entries: (order: , bytes)
TCP: Hash tables configured (established bind )
TCP: reno registered
UDP hash table entries: (order: , bytes)
UDP-Lite hash table entries: (order: , bytes)
NET: Registered protocol family
RPC: Registered named UNIX socket transport module.
RPC: Registered udp transport module.
RPC: Registered tcp transport module.
RPC: Registered tcp NFSv4. backchannel transport module.
hw perfevents: enabled with ARMv7 Cortex-A9 PMU driver, counters available
futex hash table entries: (order: , bytes)
squashfs: version 4.0 (//) Phillip Lougher
jffs2: version 2.2. (NAND) © - Red Hat, Inc.
9p: Installing v9fs 9p2000 file system support
msgmni has been set to
io scheduler noop registered (default)
clcd-pl11x: probe of .clcd failed with error -
clcd-pl11x: probe of 1001f000.clcd failed with error -
VD10: at mV
VD10_S2: at mV
VD10_S3: at mV
VCC1V8: at mV
DDR2VTT: at mV
VCC3V3: at mV
VIO: at mV
.flash: Found x16 devices at 0x0 in -bit bank. Manufacturer ID 0x000000 Chip ID 0x000000
Intel/Sharp Extended Query Table at 0x0031
Using buffer write method
.flash: Found x16 devices at 0x0 in -bit bank. Manufacturer ID 0x000000 Chip ID 0x000000
Intel/Sharp Extended Query Table at 0x0031
Using buffer write method
Concatenating MTD devices:
(): "40000000.flash"
(): "40000000.flash"
into device "40000000.flash"
libphy: smsc911x-mdio: probed
smsc911x 4e000000.ethernet eth0: attached PHY driver [Generic PHY] (mii_bus:phy_addr=4e000000.etherne:, irq=-)
smsc911x 4e000000.ethernet eth0: MAC Address: :::::
nxp-isp1760 4f000000.usb: NXP ISP1760 USB Host Controller
nxp-isp1760 4f000000.usb: new USB bus registered, assigned bus number
nxp-isp1760 4f000000.usb: Scratch test failed.
nxp-isp1760 4f000000.usb: can't setup: -19
nxp-isp1760 4f000000.usb: USB bus deregistered
usbcore: registered new interface driver usb-storage
mousedev: PS/ mouse device common for all mice
rtc-pl031 .rtc: rtc core: registered pl031 as rtc0
mmci-pl18x .mmci: Got CD GPIO #.
mmci-pl18x .mmci: Got WP GPIO #.
mmci-pl18x .mmci: No vqmmc regulator found
mmci-pl18x .mmci: mmc0: PL181 manf rev0 at 0x10005000 irq , (pio)
ledtrig-cpu: registered to indicate activity on CPUs
usbcore: registered new interface driver usbhid
usbhid: USB HID core driver
input: AT Raw Set keyboard as /devices/smb/smb:motherboard/smb:motherboard:iofpga@,/.kmi/serio0/input/input0
mmc0: new SD card at address
mmcblk0: mmc0: QEMU! 32.0 MiB
mmcblk0: unknown partition table
aaci-pl041 .aaci: ARM AC'97 Interface PL041 rev0 at 0x10004000, irq 43
aaci-pl041 .aaci: FIFO entries
oprofile: using arm/armv7-ca9
TCP: cubic registered
NET: Registered protocol family
9pnet: Installing 9P2000 support
rtc-pl031 .rtc: setting system clock to -- :: UTC ()
ALSA device list:
#: ARM AC'97 Interface PL041 rev0 at 0x10004000, irq 43
input: ImExPS/ Generic Explorer Mouse as /devices/smb/smb:motherboard/smb:motherboard:iofpga@,/.kmi/serio1/input/input2
EXT3-fs (mmcblk0): recovery required on readonly filesystem
EXT3-fs (mmcblk0): write access will be enabled during recovery
kjournald starting. Commit interval seconds
EXT3-fs (mmcblk0): recovery complete
EXT3-fs (mmcblk0): mounted filesystem with writeback data mode
VFS: Mounted root (ext3 filesystem) readonly on device :.
Freeing unused kernel memory: 236K (805c2000 - 805fd000)
random: nonblocking pool is initialized
smsc911x 4e000000.ethernet eth0: SMSC911x/921x identified at 0xa0900000, IRQ: Please press Enter to activate this console. [root@vexpress ]#
[root@vexpress ]#
[root@vexpress ]# ls /proc/device-tree/
#address-cells memory-controller@100e0000
#size-cells memory-controller@100e1000
aliases memory@
arm,hbi model
arm,vexpress,site name
cache-controller@1e00a000 pmu
chosen scu@1e000000
clcd@ smb
compatible timer@100e4000
cpus timer@1e000600
dcc watchdog@100e5000
interrupt-controller@1e001000 watchdog@1e000620
5、直接在Qemu的命令行中设置DT
执行如下命令
qemu-system-arm \
-M vexpress-a9 \
-m 512M \
-kernel /root/tq2440_work/kernel/linux-stable/out_vexpress_3_16/arch/arm/boot/zImage \
-nographic \
-append "root=/dev/mmcblk0 console=ttyAMA0" \
-sd /root/tq2440_work/busybox_study/a9rootfs.ext3 \
-dtb /tftpboot/dtb
启动信息：
Booting Linux on physical CPU 0x0
Initializing cgroup subsys cpuset
Linux version 3.16. (root@ubuntu) (gcc version 4.7. (Ubuntu/Linaro 4.7.-12ubuntu1) ) # SMP Sun Dec :: PST
CPU: ARMv7 Processor [410fc090] revision (ARMv7), cr=10c53c7d
CPU: PIPT / VIPT nonaliasing data cache, VIPT nonaliasing instruction cache
Machine model: V2P-CA9
Memory policy: Data cache writeback
CPU: All CPU(s) started in SVC mode.
PERCPU: Embedded pages/cpu @9fbcf000 s7552 r8192 d12928 u32768
Built zonelists in Zone order, mobility grouping on. Total pages:
Kernel command line: root=/dev/mmcblk0 console=ttyAMA0
PID hash table entries: (order: , bytes)
Dentry cache hash table entries: (order: , bytes)
Inode-cache hash table entries: (order: , bytes)
Memory: 513116K/524288K available (4567K kernel code, 191K rwdata, 1292K rodata, 239K init, 149K bss, 11172K reserved)
Virtual kernel memory layout:
vector : 0xffff0000 - 0xffff1000 ( kB)
fixmap : 0xffc00000 - 0xffe00000 ( kB)
vmalloc : 0xa0800000 - 0xff000000 ( MB)
lowmem : 0x80000000 - 0xa0000000 ( MB)
modules : 0x7f000000 - 0x80000000 ( MB)
.text : 0x80008000 - 0x805c1238 ( kB)
.init : 0x805c2000 - 0x805fdd80 ( kB)
.data : 0x805fe000 - 0x8062dc20 ( kB)
.bss : 0x8062dc28 - 0x806533ec ( kB)
SLUB: HWalign=, Order=-, MinObjects=, CPUs=, Nodes=
Hierarchical RCU implementation.
RCU restricting CPUs from NR_CPUS= to nr_cpu_ids=.
RCU: Adjusting geometry for rcu_fanout_leaf=, nr_cpu_ids=
NR_IRQS: nr_irqs:
GIC CPU mask not found - kernel will fail to boot.
GIC CPU mask not found - kernel will fail to boot.
sched_clock: bits at 24MHz, resolution 41ns, wraps every 178956969942ns
Console: colour dummy device 80x30
Calibrating delay loop... 286.10 BogoMIPS (lpj=)
pid_max: default: minimum:
Mount-cache hash table entries: (order: , bytes)
Mountpoint-cache hash table entries: (order: , bytes)
CPU: Testing write buffer coherency: ok
CPU0: thread -, cpu , socket , mpidr
Setting up static identity map for 0x60455850 - 0x604558a8
CPU1: failed to boot: -
CPU2: failed to boot: -
CPU3: failed to boot: -
Brought up CPUs
SMP: Total of processors activated.
CPU: All CPU(s) started in SVC mode.
devtmpfs: initialized
VFP support v0.: implementor architecture part variant rev
regulator-dummy: no parameters
NET: Registered protocol family
DMA: preallocated KiB pool for atomic coherent allocations
cpuidle: using governor ladder
cpuidle: using governor menu
of_amba_device_create(): amba_device_add() failed (-) for /memory-controller@100e0000
of_amba_device_create(): amba_device_add() failed (-) for /memory-controller@100e1000
of_amba_device_create(): amba_device_add() failed (-) for /watchdog@100e5000
of_amba_device_create(): amba_device_add() failed (-) for /smb/motherboard/iofpga@,/sysctl@
of_amba_device_create(): amba_device_add() failed (-) for /smb/motherboard/iofpga@,/wdt@0f000
hw-breakpoint: debug architecture 0x4 unsupported.
Serial: AMBA PL011 UART driver
.uart: ttyAMA0 at MMIO 0x10009000 (irq = , base_baud = ) is a PL011 rev1
console [ttyAMA0] enabled
1000a000.uart: ttyAMA1 at MMIO 0x1000a000 (irq = , base_baud = ) is a PL011 rev1
1000b000.uart: ttyAMA2 at MMIO 0x1000b000 (irq = , base_baud = ) is a PL011 rev1
1000c000.uart: ttyAMA3 at MMIO 0x1000c000 (irq = , base_baud = ) is a PL011 rev1
3V3: mV
SCSI subsystem initialized
usbcore: registered new interface driver usbfs
usbcore: registered new interface driver hub
usbcore: registered new device driver usb
Advanced Linux Sound Architecture Driver Initialized.
Switched to clocksource arm,sp804
NET: Registered protocol family
TCP established hash table entries: (order: , bytes)
TCP bind hash table entries: (order: , bytes)
TCP: Hash tables configured (established bind )
TCP: reno registered
UDP hash table entries: (order: , bytes)
UDP-Lite hash table entries: (order: , bytes)
NET: Registered protocol family
RPC: Registered named UNIX socket transport module.
RPC: Registered udp transport module.
RPC: Registered tcp transport module.
RPC: Registered tcp NFSv4. backchannel transport module.
hw perfevents: enabled with ARMv7 Cortex-A9 PMU driver, counters available
futex hash table entries: (order: , bytes)
squashfs: version 4.0 (//) Phillip Lougher
jffs2: version 2.2. (NAND) © - Red Hat, Inc.
9p: Installing v9fs 9p2000 file system support
msgmni has been set to
io scheduler noop registered (default)
clcd-pl11x: probe of .clcd failed with error -
clcd-pl11x: probe of 1001f000.clcd failed with error -
VD10: at mV
VD10_S2: at mV
VD10_S3: at mV
VCC1V8: at mV
DDR2VTT: at mV
VCC3V3: at mV
VIO: at mV
.flash: Found x16 devices at 0x0 in -bit bank. Manufacturer ID 0x000000 Chip ID 0x000000
Intel/Sharp Extended Query Table at 0x0031
Using buffer write method
.flash: Found x16 devices at 0x0 in -bit bank. Manufacturer ID 0x000000 Chip ID 0x000000
Intel/Sharp Extended Query Table at 0x0031
Using buffer write method
Concatenating MTD devices:
(): "40000000.flash"
(): "40000000.flash"
into device "40000000.flash"
libphy: smsc911x-mdio: probed
smsc911x 4e000000.ethernet eth0: attached PHY driver [Generic PHY] (mii_bus:phy_addr=4e000000.etherne:, irq=-)
smsc911x 4e000000.ethernet eth0: MAC Address: :::::
nxp-isp1760 4f000000.usb: NXP ISP1760 USB Host Controller
nxp-isp1760 4f000000.usb: new USB bus registered, assigned bus number
nxp-isp1760 4f000000.usb: Scratch test failed.
nxp-isp1760 4f000000.usb: can't setup: -19
nxp-isp1760 4f000000.usb: USB bus deregistered
usbcore: registered new interface driver usb-storage
mousedev: PS/ mouse device common for all mice
rtc-pl031 .rtc: rtc core: registered pl031 as rtc0
mmci-pl18x .mmci: Got CD GPIO #.
mmci-pl18x .mmci: Got WP GPIO #.
mmci-pl18x .mmci: No vqmmc regulator found
mmci-pl18x .mmci: mmc0: PL181 manf rev0 at 0x10005000 irq , (pio)
ledtrig-cpu: registered to indicate activity on CPUs
usbcore: registered new interface driver usbhid
usbhid: USB HID core driver
input: AT Raw Set keyboard as /devices/smb/smb:motherboard/smb:motherboard:iofpga@,/.kmi/serio0/input/input0
mmc0: new SD card at address
mmcblk0: mmc0: QEMU! 32.0 MiB
mmcblk0: unknown partition table
aaci-pl041 .aaci: ARM AC'97 Interface PL041 rev0 at 0x10004000, irq 43
aaci-pl041 .aaci: FIFO entries
oprofile: using arm/armv7-ca9
TCP: cubic registered
NET: Registered protocol family
9pnet: Installing 9P2000 support
rtc-pl031 .rtc: setting system clock to -- :: UTC ()
ALSA device list:
#: ARM AC'97 Interface PL041 rev0 at 0x10004000, irq 43
input: ImExPS/ Generic Explorer Mouse as /devices/smb/smb:motherboard/smb:motherboard:iofpga@,/.kmi/serio1/input/input2
kjournald starting. Commit interval seconds
EXT3-fs (mmcblk0): mounted filesystem with writeback data mode
VFS: Mounted root (ext3 filesystem) readonly on device :.
Freeing unused kernel memory: 236K (805c2000 - 805fd000)
random: nonblocking pool is initialized
smsc911x 4e000000.ethernet eth0: SMSC911x/921x identified at 0xa0900000, IRQ: Please press Enter to activate this console. [root@vexpress ]#
未完待续。
用Qemu模拟vexpress-a9 （五） --- u-boot引导kernel，device tree的使用的更多相关文章
- 用Qemu模拟vexpress-a9 （四） --- u-boot引导kernel，用nfs挂载根文件系统
环境介绍 Win7 64 + Vmware 11 + ubuntu14.04 32 u-boot 版本:u-boot-2015-04 Linux kernel版本:linux-3.16.y busyb ...
- 用Qemu模拟vexpress-a9 （一） --- 搭建Linux kernel调试环境【转】
转自:http://www.cnblogs.com/pengdonglin137/p/5023342.html#_label2 阅读目录(Content) 环境介绍: 下载Linux内核 安装arm的 ...
- 用Qemu模拟vexpress-a9 （一） --- 搭建Linux kernel调试环境
参考: http://blog.csdn.net/linyt/article/details/42504975 环境介绍: Win7 64 + Vmware 11 + ubuntu14.04 32 u ...
- qemu 模拟-arm-mini2440开发板-启动u-boot，kernel和nfs文件系统
qemu 本文介绍了如何编译u-boot.linux kernel,然后用qemu启动u-boot和linux kernel,达到与开发板上一样的学习效果! 虽然已经买了2440开发板,但是在实际学习 ...
- qemu 模拟-arm-mini2440开发板-启动u-boot，kernel和nfs文件系统【转】
转自:http://www.cnblogs.com/riskyer/p/3366001.html qemu 本文介绍了如何编译u-boot.linux kernel,然后用qemu启动u-boot和l ...
- CentOS 7 利用qemu模拟ARM vexpress A9开发板
听说qemu用于仿真arm很不错,今日就来试了一把.由于刚刚开始,了解的并不多.本文仅仅记录Qemu装载Linux kernel和busybox根文件系统的过程.后续将会深入了解仿真的其他内容. 先上 ...
- 用QEMU模拟运行uboot从SD卡启动Linux
平台:Qemu + vexpress-a9 u-boot:u-boot-2019.10 Linux:linux-4.14.13 之前介绍过用Qemu模拟运行uboot,然后从网络启动lin ...
- 利用qemu模拟嵌入式系统制作全过程
http://www.tinylab.org/using-qemu-simulation-inserts-the-type-system-to-produce-the-whole-process/ 利 ...
- 以Qemu模拟Linux，学习Linux内核
文章名称:以Qemu模拟Linux,学习Linux内核作 者:five_cent文章地址:http://www.cnblogs.com/senix/archive/2013/02/21/29 ...
随机推荐
- js错误处理
导致程序无法继续执行的异常状态称为错误. js中一旦发生错误,就会自动创建一个Error类型对象 js中有6中错误类型: SyntaxError 语法错误 ReferenceError 引用错误,找不 ...
- #error#错误原因:Cannot find executable for CFBundle 0x8ad60b0 (not loaded)
#error#错误原因:Cannot find executable for CFBundle 0x8ad60b0 </Applications/Xcode.app/Contents/Devel ...
- 微信小程序登录状态
我们知道,WEB服务器通过浏览器携带的cookie获取session来判断是否是同一用户(或浏览器):Restful服务通过客户端传过来唯一ID,来识别调用用户. >为什么需要维护登录态? 有自 ...
- HBase表操作
相对于0.9.X版本,在HBase1.X版本对内部API改动比较大,例如连接部分类库变更,如下: 连接获取:org.apache.hadoop.hbase.HBaseConfiguration.cre ...
- React 踩坑记录
1.React-router error: super expression must either be null or a function 原因:引入babel后写ES6风格的代码: class ...
- TCP三次握手四次分手
TCP(Transmission Control Protocol) 传输控制协议 TCP是主机对主机层的传输控制协议,提供可靠的连接服务,采用三次握手确认建立一个连接: 位码即tcp标志位,有6种标 ...
- Oracle基础 07 参数文件 pfile/spfile
--查看数据库运行模式(spfile还是pfile)select decode(count(*),1,'spfile','pfile') from v$spparameterwhere rownum= ...
- 8.read读取控制台输入
read(选项)(参数)选项:-p:指定读取值时的提示符-t:指定读取时等待的时间(秒),如果没有在指定的时间内输入,就不再等待了参数:变量:指定读取时的变量名
- C# 调试程序时如何输入命令行参数
调试程序时如何输入命令行参数http://www.a769.com/archives/320.html 开发命令行程序时,我们会疑惑,从那里输入参数呢?请看下面的教程,让你摆脱困扰. 1.点击菜单栏: ...
- 内存可见性，指令重排序，JIT。。。。。。从一个知乎问题谈起
在知乎上看到一个问题<java中volatile关键字的疑惑?>,引起了我的兴趣 问题是这样的: package com.cc.test.volatileTest; public clas ...