Emulate ARM x64 architecture
Emulate ARMx32 architecture https://934.medium.com/emulate-arm-x-32-architecture-ede39ab6a33b
In the before article, we learn how to configure ARM x32 step by step. Now we will learn about ARM x64 architecture.
In this section we will learn install, assemble, link and debug in this architecture.
Install some GNU and Linux tools:
$ sudo apt-get update && sudo apt-get upgrade -y
$ sudo apt-get install build-essential
Compiler
$ sudo apt-get install gcc-aarch64-linux-gnu g++-aarch64-linux-gnu binutils-aarch64-linux-gnu binutils-aarch64-linux-gnu-dbg
For emulate, execute and debuger we use:
$ sudo apt-get install qemu-user qemu-user-static
Debugger
$ sudo apt-get install gdb-multiarch
Compile
For testing, we create a file called hello_armx64.s
$ vim hello_armx64.s
Assemble
$ /usr/aarch64-linux-gnu/bin/as -g hello_armx64.s -o hello_armx64.o
or
$ aarch64-linux-gnu-as -g hello_armx64.s -o hello_armx64.o
Note: don’t forget flag -g for debugging
Link
$ /usr/aarch64-linux-gnu/bin/ld hello_armx64.o -o hello_armx64
or
$ aarch64-linux-gnu-ld hello_armx64.o -o hello_armx64
Execute
$ ./hello_armx64
or
$ qemu-aarch64 ./hello_armx64
Debugger
We go to use qemu-arm and gdb-multiarch for debugging program because ARM processor use different registers and qemu helps to emulate them.
First step:
Create a gdb server with qemu and its port with this command:
$ qemu-arm -L /usr/aarch64-linux-gnu -g 1234 ./hello_armx64
Note: you can use another number for the port but it must be the same in gdb-multiarch.
It waits for response. Then, start gdb-multiarch with next commands:
$ gdb-multiarch -q — nh -ex ‘set architecture arm’ -ex ‘file hello_armx64’ -ex ‘target remote :1234’ -ex ‘layout split’ -ex ‘layout regs’
- -q : Do not print version number on startup.
- — nh: Do not read ~/.gdbinit.
- -ex: Execute a single GDB command.
- Set architecture arm: specifies type of architecture
- Layout split: Divide screen to show code.
- Layout regs: Shows all registers of ARM achitecture.
Note: You can remove some flags used for gdb-multiarch like layout split or layout regs but never -ex ‘target remote : 1234’ it binds with qemu port.
start to debug:
(gdb) b _start
Note: dont use gdb command: run only next or si (stepi)
(gdb ) net
Note: gdb uses normal commands for debugging.
That’s all. Now we have to learn how to configure ARM x
