Till now, I only know how to exit a program by gnu arm assembly.
#exit(0)
mov r0, #0 # return code
mov r7, #1 # supervisor service number
svc # call supervisor service
But there are still many other syscalls like read, write, fork... I suppose that each of them will require different service number, different numbers of registers as arguments and different rules on how to use registers. My question is where I can get information on writing assembly for each of them. I searched google but the information is less on this topic.
You can take an approach like Android's Bionic and generate sys call stubs via some metadata and a script or use Bionic's directly.
Below is from Bionic's libc/SYSCALLS.TXT
# this file is used to list all the syscalls that will be supported by
# the Bionic C library. It is used to automatically generate the syscall
# stubs, the list of syscall constants (__NR_xxxx) and the content of <linux/_unistd.h>
#
# each non comment line has the following format:
#
# return_type func_name[:syscall_name[:call_id]]([parameter_list]) (syscall_number|"stub")
#
# note that:
# - syscall_name correspond to the name of the syscall, which may differ from
# the exported function name (example: the exit syscall is implemented by the _exit()
# function, which is not the same as the standard C exit() function which calls it)
# The call_id parameter, given that func_name and syscall_name have
# been provided, allows the user to specify dispatch style syscalls.
# For example, socket() syscall on i386 actually becomes:
# socketcall(__NR_socket, 1, *(rest of args on stack)).
#
# - each parameter type is assumed to be stored on 32 bits, there is no plan to support
# 64-bit architectures at the moment
#
# - it there is "stub" instead of a syscall number, the tool will not generate any
# assembler template for the syscall; it's up to the bionic implementation to provide
# a relevant C stub
#
# - additionally, if the syscall number is different amoung ARM, and x86, MIPS use:
# return_type funcname[:syscall_name](parameters) arm_number,x86_number,mips_number
#
# the file is processed by a python script named gensyscalls.py
#
# process management
void _exit:exit_group (int) 248,252,246
void _exit_thread:exit (int) 1
pid_t __fork:fork (void) 2
<skipped rest of the file>
来源：https://stackoverflow.com/questions/19285992/in-linux-how-to-do-system-calls-through-gnu-arm-assembly