我正在使用支持 OpenSDA 的MK64FN1M0xxx12开发套件。为了让调试更容易，我刷了支持 SEGGER 调试器命令集的J-Link固件。在这样做之前，我确保我的设备得到官方支持。
更详细地说，我正在尝试调试mbed-os 5，特别是uVisor安全补丁。uVisor Github 页面有一个调试文章，提供了通过 GDB 会话连接到设备以接收调试打印的说明。我能够正确连接 J-Link 会话，但我似乎无法实际调试二进制文件。此外，我似乎无法正确刷新设备。不过，我可以将二进制文件推送到设备 RAM。
他们的指示是：
(gdb) target remote localhost:2331
(gdb) monitor reset
(gdb) monitor halt
(gdb) monitor semihosting enable
(gdb) monitor loadbin ./build/${target}/source/${your_app}.bin 0
(gdb) monitor flash device = ${device_name}
(gdb) load ./build/${target}/source/${your_app}
(gdb) file ./build/${target}/source/${your_app}
所以，我试图复制他们的工作。通过 J-Link 连接到设备
$ JLinkGDBServer -device MK64FN1M0xxx12
SEGGER J-Link GDB Server V6.00g Command Line Version
JLinkARM.dll V6.00g (DLL compiled Aug 17 2016 13:20:32)
-----GDB Server start settings-----
GDBInit file: none
GDB Server Listening port: 2331
SWO raw output listening port: 2332
Terminal I/O port: 2333
Accept remote connection: yes
Generate logfile: off
Verify download: off
Init regs on start: off
Silent mode: off
Single run mode: off
Target connection timeout: 0 ms
------J-Link related settings------
J-Link Host interface: USB
J-Link script: none
J-Link settings file: none
------Target related settings------
Target device: MK64FN1M0xxx12
Target interface: JTAG
Target interface speed: 1000kHz
Target endian: little
Connecting to J-Link...
J-Link is connected.
Firmware: J-Link OpenSDA 2 compiled Sep 15 2016 14:57:31
Hardware: V1.00
S/N: 621000000
Checking target voltage...
Target voltage: 3.30 V
Listening on TCP/IP port 2331
Connecting to target...ERROR: Debugger tries to select target interface JTAG.
This interface is not supported by the connected emulator.
Selection will be ignored by the DLL.
J-Link found 1 JTAG device, Total IRLen = 4
JTAG ID: 0x2BA01477 (Cortex-M4)
Connected to target
Waiting for GDB connection...
建立 GDB 客户端会话
(gdb) target remote localhost:2331
Remote debugging using localhost:2331
0x200171fe in ?? ()
(gdb) monitor reset
Resetting target
(gdb) monitor halt
(gdb) monitor semihosting enable
Semi-hosting enabled (Handle on BKPT)
(gdb) monitor flash download 1
Flash download enabled
(gdb) shell cp ../.build/K64F/GCC_ARM/mbed-os-example-uvisor.bin /tmp
(gdb) monitor loadbin /tmp/mbed-os-example-uvisor.bin
Binary file loaded successfully (210240 bytes downloaded)
(gdb) monitor flash device = MK64FN1M0xxx12
Selecting device: MK64FN1M0xxx12
(gdb) load ../.build/K64F/GCC_ARM/source/main.o
Loading section .text._ZN4rtos6ThreadC2E10osPrioritymPh, size 0x54 lma 0x0
Loading section .text._ZN16NetworkInterfaceD2Ev, size 0x28 lma 0x0
Loading section .text._ZN16NetworkInterfaceD0Ev, size 0x1c lma 0x0
Loading section .text._ZN4mbed10DigitalOutC2E7PinName, size 0x24 lma 0x0
Loading section .text._ZN4mbed10DigitalOut5writeEi, size 0x1c lma 0x0
Loading section .text._ZN4mbed10DigitalOutaSEi, size 0x1c lma 0x0
Loading section .rodata._ZL10g_main_acl, size 0xc0 lma 0x0
Loading section .rodata.__uvisor_priv_sys_irq_hooks, size 0xc lma 0x0
Loading section .keep.uvisor.bss.boxes, size 0x80 lma 0x0
Loading section .rodata.__uvisor_mode, size 0x4 lma 0x0
Loading section .keep.uvisor.cfgtbl, size 0x28 lma 0x0
Loading section .keep.uvisor.cfgtbl_ptr_first, size 0x4 lma 0x0
Loading section .text._Z30local_ENET_Transmit_IRQHandlerv, size 0x14 lma 0x0
Loading section .text._Z29local_ENET_Receive_IRQHandlerv, size 0x14 lma 0x0
Loading section .text._ZN16NetworkInterfaceC2Ev, size 0x18 lma 0x0
Loading section .text._ZN12EthInterfaceC2Ev, size 0x24 lma 0x0
Loading section .text._ZN12EthInterfaceD2Ev, size 0x30 lma 0x0
Loading section .text._ZN12EthInterfaceD0Ev, size 0x1c lma 0x0
Loading section .text._ZN17EthernetInterfaceC2Ev, size 0x24 lma 0x0
Loading section .rodata, size 0xd4 lma 0x0
Loading section .text._Z16ethernet_connectv, size 0x54 lma 0x0
Loading section .text.main, size 0x174 lma 0x0
Loading section .text._ZN4mbed8CallbackIFvvEEC2EPS1_, size 0x1c lma 0x0
Loading section .text._ZN4mbed8CallbackIFvvEE6attachEPS1_, size 0x30 lma 0x0
Loading section .text._ZN4mbed8CallbackIFvvEE12_staticthunkEPvS3_, size 0x14 lma 0x0
Loading section .rodata._ZTV12EthInterface, size 0x24 lma 0x0
Loading section .rodata._ZTV16NetworkInterface, size 0x18 lma 0x0
Loading section .text._ZN17EthernetInterfaceD2Ev, size 0x30 lma 0x0
Loading section .text._ZN17EthernetInterfaceD0Ev, size 0x1c lma 0x0
Loading section .text._Z41__static_initialization_and_destruction_0ii, size 0x3c lma 0x0
Loading section .text._GLOBAL__sub_I___uvisor_priv_sys_irq_hooks, size 0x10 lma 0x0
Loading section .init_array, size 0x4 lma 0x0
Start address 0x0, load size 1816
Transfer rate: 1773 KB/sec, 56 bytes/write.
(gdb) file ../.build/K64F/GCC_ARM/source/main.o
A program is being debugged already.
Are you sure you want to change the file? (y or n) y
Reading symbols from ../.build/K64F/GCC_ARM/source/main.o...done.
(gdb) c
Continuing.
Program received signal SIGTRAP, Trace/breakpoint trap.
rtos::Thread::Thread (this=<error reading variable: Cannot access memory at address 0xfffffff4>, priority=<error reading variable: Cannot access memory at address 0xfffffff2>, stack_size=<error reading variable: Cannot access memory at address 0xffffffec>,
stack_pointer=<error reading variable: Cannot access memory at address 0xffffffe8>) at ../mbed-os/rtos/rtos/Thread.h:42
42 Thread(osPriority priority=osPriorityNormal,
(gdb)
生成的 J-Link 控制台输出
Waiting for GDB connection...Connected to 127.0.0.1
Reading all registers
Read 4 bytes @ address 0x200171FE (Data = 0xEA126221)
Read 2 bytes @ address 0x200171FE (Data = 0x6221)
Resetting target
Halting target CPU...
...Target halted (PC = 0x200171FE)
Semi-hosting enabled (Handle on BKPT)
Flash download enabled
Loading binary file [/tmp/mbed-os-example-uvisor.bin] ...
Downloading 210240 bytes @ address 0x00000000
Binary file loaded successfully (210240 bytes downloaded)
Selecting device: MK64FN1M0xxx12
Downloading 84 bytes @ address 0x00000000
Downloading 40 bytes @ address 0x00000000
Downloading 28 bytes @ address 0x00000000
Downloading 36 bytes @ address 0x00000000
Downloading 28 bytes @ address 0x00000000
Downloading 28 bytes @ address 0x00000000
Downloading 192 bytes @ address 0x00000000
Downloading 12 bytes @ address 0x00000000
Downloading 128 bytes @ address 0x00000000
Downloading 4 bytes @ address 0x00000000
Downloading 40 bytes @ address 0x00000000
Downloading 4 bytes @ address 0x00000000
Downloading 20 bytes @ address 0x00000000
Downloading 20 bytes @ address 0x00000000
Downloading 24 bytes @ address 0x00000000
Downloading 36 bytes @ address 0x00000000
Downloading 48 bytes @ address 0x00000000
Downloading 28 bytes @ address 0x00000000
Downloading 36 bytes @ address 0x00000000
Downloading 212 bytes @ address 0x00000000
Downloading 84 bytes @ address 0x00000000
Downloading 372 bytes @ address 0x00000000
Downloading 28 bytes @ address 0x00000000
Downloading 48 bytes @ address 0x00000000
Downloading 20 bytes @ address 0x00000000
Downloading 36 bytes @ address 0x00000000
Downloading 24 bytes @ address 0x00000000
Downloading 48 bytes @ address 0x00000000
Downloading 28 bytes @ address 0x00000000
Downloading 60 bytes @ address 0x00000000
Downloading 16 bytes @ address 0x00000000
Downloading 4 bytes @ address 0x00000000
Writing register (PC = 0x00000000)
Read 4 bytes @ address 0x00000000 (Data = 0x00000000)
Read 2 bytes @ address 0x00000000 (Data = 0x0000)
Reading all registers
Read 4 bytes @ address 0x00000000 (Data = 0x00000000)
Starting target CPU...
ERROR: Can not read register 15 (R15) while CPU is running
Reading all registers
ERROR: Can not read register 0 (R0) while CPU is running
ERROR: Can not read register 1 (R1) while CPU is running
ERROR: Can not read register 2 (R2) while CPU is running
ERROR: Can not read register 3 (R3) while CPU is running
ERROR: Can not read register 4 (R4) while CPU is running
ERROR: Can not read register 5 (R5) while CPU is running
ERROR: Can not read register 6 (R6) while CPU is running
ERROR: Can not read register 7 (R7) while CPU is running
ERROR: Can not read register 8 (R8) while CPU is running
ERROR: Can not read register 9 (R9) while CPU is running
ERROR: Can not read register 10 (R10) while CPU is running
ERROR: Can not read register 11 (R11) while CPU is running
ERROR: Can not read register 12 (R12) while CPU is running
ERROR: Can not read register 13 (R13) while CPU is running
ERROR: Can not read register 14 (R14) while CPU is running
ERROR: Can not read register 15 (R15) while CPU is running
ERROR: Can not read register 16 (XPSR) while CPU is running
ERROR: Can not read register 17 (MSP) while CPU is running
ERROR: Can not read register 18 (PSP) while CPU is running
ERROR: Can not read register 24 (PRIMASK) while CPU is running
ERROR: Can not read register 25 (BASEPRI) while CPU is running
ERROR: Can not read register 26 (FAULTMASK) while CPU is running
ERROR: Can not read register 27 (CONTROL) while CPU is running
ERROR: Can not read register 32 (FPSCR) while CPU is running
ERROR: Can not read register 33 (FPS0) while CPU is running
ERROR: Can not read register 34 (FPS1) while CPU is running
ERROR: Can not read register 35 (FPS2) while CPU is running
ERROR: Can not read register 36 (FPS3) while CPU is running
ERROR: Can not read register 37 (FPS4) while CPU is running
ERROR: Can not read register 38 (FPS5) while CPU is running
ERROR: Can not read register 39 (FPS6) while CPU is running
ERROR: Can not read register 40 (FPS7) while CPU is running
ERROR: Can not read register 41 (FPS8) while CPU is running
ERROR: Can not read register 42 (FPS9) while CPU is running
ERROR: Can not read register 43 (FPS10) while CPU is running
ERROR: Can not read register 44 (FPS11) while CPU is running
ERROR: Can not read register 45 (FPS12) while CPU is running
ERROR: Can not read register 46 (FPS13) while CPU is running
ERROR: Can not read register 47 (FPS14) while CPU is running
ERROR: Can not read register 48 (FPS15) while CPU is running
ERROR: Can not read register 49 (FPS16) while CPU is running
ERROR: Can not read register 50 (FPS17) while CPU is running
ERROR: Can not read register 51 (FPS18) while CPU is running
ERROR: Can not read register 52 (FPS19) while CPU is running
ERROR: Can not read register 53 (FPS20) while CPU is running
ERROR: Can not read register 54 (FPS21) while CPU is running
ERROR: Can not read register 55 (FPS22) while CPU is running
ERROR: Can not read register 56 (FPS23) while CPU is running
ERROR: Can not read register 57 (FPS24) while CPU is running
ERROR: Can not read register 58 (FPS25) while CPU is running
ERROR: Can not read register 59 (FPS26) while CPU is running
ERROR: Can not read register 60 (FPS27) while CPU is running
ERROR: Can not read register 61 (FPS28) while CPU is running
ERROR: Can not read register 62 (FPS29) while CPU is running
ERROR: Can not read register 63 (FPS30) while CPU is running
ERROR: Can not read register 64 (FPS31) while CPU is running
Read 4 bytes @ address 0x00000000 (Data = 0x00000000)
Read 4 bytes @ address 0x00000000 (Data = 0x00000000)
Read 4 bytes @ address 0x00000000 (Data = 0x00000000)
WARNING: Failed to read memory @ address 0xFFFFFFF4
WARNING: Failed to read memory @ address 0xFFFFFFF2
WARNING: Failed to read memory @ address 0xFFFFFFEC
WARNING: Failed to read memory @ address 0xFFFFFFE8
似乎事情几乎可以正常工作，但我对 GDB 的了解还不够，无法知道哪里可能出现故障。从 J-Link 控制台输出看来，第二个似乎load正在覆盖 RAM 的早期内容。如果我省略此指令（但保留最后一条file命令），则不会报告任何错误，但连接 vianc不会显示任何调试消息
$ nc localhost 2333
SEGGER J-Link GDB Server V6.00g - Terminal output channel
尽管 uVisor 调试记录（遵循 GDB 命令列表）表明许多类型的消息应该在运行时报告。除此之外，我的程序（看似）成功下载到开发板上，在执行时表现不佳（没有闪烁的 LED 等）。
正如我之前使用 uVisor 发现的（因为它非常新），文档可能已经过时了。此外，我通过研究发现其他人需要使用该monitor flash download = 1命令来启用闪存编程，尽管它似乎对我不起作用。尽管此命令的输出为Flash download enabled，但据我所知，没有任何内容写入闪存（考虑到输出和经过的时间）。