GDB cross compiler

objective

• compile gdb static for mips /el

pre

• create build and source folders
• download gdb 7.9 and termcap 1.3.1 to source folder
• create cross compiler with buildroot or crosstool-ng (i used buildroot)

termcap

under build folder create sub folder 

(host)$mkdir -p build/termcap/mipsel

(host)$export CC=<path>/buildroot/output/mipsel/host/usr/bin/mipsel-linux-gcc

(host)$./configure --host=mipsel-linux --prefix='/<path>/build/termcap/mipsel/'

(host)$make

(host)$make install

gdb 7.9

(host)set PATH=/to/gcc/folder

(host)$cd to gdb-7.9 folder #don't run process from gdb subfolder see README

(host)$export CC=<path>/buildroot/output/mipsel/host/usr/bin/mipsel-linux-gcc

#set ld flags: static and point to termcap lib folder

(host)$export LDFLAGS="-static -L/<path>/build/termcap/mipsel/lib"

#set include to termcap include folder

(host)$export CFLAGS="-g -O2 -I/<path>/build/termcap/mipsel/include"

(host)$./configure --host=mipsel-linux --prefix='/<path>/build/gdb_mipsel' --disable-werror

(host)$make

(host)$make install

Note

host: compiler prefix

reference

http://tigertop.blogspot.co.il/2011/03/building-gdb-72-for-arm-architecture-on.html

first mips assembly

LAB

objective

• compile mips assembly with gcc
• run in emulation

setup

• gcc: aboriginal cross compiler , mipsel
• emulator: qemu-user-static

sudo apt-get install qemu-user-static

vim exit.S

#include <sys/regdef.h>

#include <asm/unistd.h>

.data

.text

.global main

main:

        .set noreorder

        .cpload t9

        .set reorder

        li a0, 99

        li v0, __NR_exit

        syscall

note: file ext must be capital S

compile

include cross gcc in path or point run directly

$mipsel-gcc -o exit exit.S

run

copy qemu to chroot folder

$cp $(which qemu-mipsel-static) .

$sudo chroot . ./qemu-mipsel-static ./exit

/lib/ld-uClibc.so.0: No such file or directory

we get error because we compile dynamicly and the lib folder not include in chroot folder

we need to bind the lib folder for outside the chroot to chroot location

$mkdir lib

$sudo mount --bind <path/to/cross_compile/lib> lib

$sudo chroot . ./qemu-mipsel-static ./exit

checking

echo $?

99 # the return value for exit syscall

tcpdump

https://danielmiessler.com/study/tcpdump/