How set set entry point in a elf target using ld script

Question

I want to specify the entry point to my ELF file using the linker script. I already defined some sections in my ELF, so want to set an entry point also withit. Can anyone tell me how to do it?

Answer 1

There's a special (GNU) linker script command that sets entry point to given symbol's address ENTRY(symbol). Refer to official documentation.

Answer 2

First get the current linker script to a file with:

ld --verbose a.o | sed '/======/,/======/!d;//d' > myscript

Here we filtered the lines between =====, as mentioned at: How to select lines between two marker patterns which may occur multiple times with awk/sed

Then edit the ENTRY(_start) line to your desired symbol.

Finally use -T to select the custom script:

ld --verbose -T myscript a.o

Answer 3

Looks like the command line argument -e entryName is the way to go about it. A man ld should give you a heads up as well.