我正在运行Ubuntu 20.04.1 LTS,lscpu
回答以下问题:
Architecture: aarch64
CPU op-mode(s): 32-bit, 64-bit
Byte Order: Little Endian
CPU(s): 4
On-line CPU(s) list: 0-3
Thread(s) per core: 1
Core(s) per socket: 4
Socket(s): 1
NUMA node(s): 1
Vendor ID: ARM
Model: 0
Model name: Cortex-A57
Stepping: r1p0
BogoMIPS: 125.00
NUMA node0 CPU(s): 0-3
Vulnerability Itlb multihit: Not affected
Vulnerability L1tf: Not affected
Vulnerability Mds: Not affected
Vulnerability Meltdown: Not affected
Vulnerability Spec store bypass: Vulnerable
Vulnerability Spectre v1: Mitigation; __user pointer sanitization
Vulnerability Spectre v2: Vulnerable
Vulnerability Srbds: Not affected
Vulnerability Tsx async abort: Not affected
Flags: fp asimd evtstrm aes pmull sha1 sha2 crc32 cpuid
我创建了一个琐碎的汇编语言程序,如下所示:
.text
.global _start
_start:
MOV R0, #1
LDR R1, =hello
LDR R2, =hello_size
MOV R7, #4
SWI 0
MOV R7, #1
SWI 0
.data
hello: .asciz "Happy Fridayn"
.equ hello_size, (.-hello)
我用以下代码编译它:
arm-linux-gnueabihf-as -ggdb hello.s -o out.o
arm-linux-gnueabihf-ld out.o -o out -lc -dynamic-linker=/usr/arm-linux-gnueabihf/lib/ld-linux-armhf.so.3
当我直接从命令行运行它时,它会打印出预期的输出("Happy Friday"(。我可以按如下方式分解代码:
$ objdump -d out
out: file format elf32-littlearm
Disassembly of section .text:
0001016c <_start>:
1016c: e3a00001 mov r0, #1
10170: e59f1010 ldr r1, [pc, #16] ; 10188 <_start+0x1c>
10174: e59f2010 ldr r2, [pc, #16] ; 1018c <_start+0x20>
10178: e3a07004 mov r7, #4
1017c: ef000000 svc 0x00000000
10180: e3a07001 mov r7, #1
10184: ef000000 svc 0x00000000
10188: 0002100c .word 0x0002100c
1018c: 0000000e .word 0x0000000e
我想在调试器中运行它(作为我正在教授的ARM汇编语言课程的一部分(。我是这样做的:
$ gdb out
GNU gdb (Ubuntu 9.2-0ubuntu1~20.04) 9.2
...
Reading symbols from out...
(gdb) b _start
Breakpoint 1 at 0x1016c: file hello.s, line 4.
(gdb) run
Starting program: /home/fostja/code/280/samples/out
此时程序挂起。中断程序会产生以下情况:
^C
Program received signal SIGINT, Interrupt.
0x0000aaaadca1a284 in ?? ()
(gdb) bt
#0 0x0000aaaadca1a284 in ?? ()
#1 0x000000000000afc7 in ?? ()
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
(gdb)
我不知道为什么它一直挂着,从来没有到达第一个断点。起初,我认为这与Qemu模拟应该在调试器中触发断点的指令有关(我首先在Proxmox上尝试了这一点,所以大部分讨论都集中在那里(,但现在它似乎与32位和64位有关。
A";固定的";gdb
中的bug似乎非常相似。看看这个和这个。
如果gdb
在主机上的qemu
的外部运行,则会回答此问题。这个问题并非如此
您需要在qemu中使用gdbserver,然后连接到它。
在qemu中:
(qemu) gdbserver
gdbserver
Waiting for gdb connection on device 'tcp::1234'
在gdb中,您必须连接到它(可能需要调整以与qemu的输出一致(:
(gdb) target remote localhost:1234
Remote debugging using localhost:1234
来源:https://linux.postach.io/post/debugging-linux-kernel-using-virtual-machine-qemu-monitor-and-gdb(或者几乎任何其他提到gdbserver和qemu的网站(