I’m trying to write a linker file to get C code running on a risc-v MCU (using riscv64-unknown-elf toolchain). My linker script looks like this, simplified:
MEMORY {
IRAM (rx) : ORIGIN = 0x00000000, LENGTH = 1024
}
ENTRY(_start)
SECTIONS {
.text : ALIGN(4) {
*(.text)
} >IRAM
...
readelf -h correctly shows the entry point’s address to be the same as where _start is in the output executable. But I want _start to be at 0x0, not somewhere else, so that when I objcopy it to a flat binary, the start code will be at the beginning. How can I do this?
Right now I’m having the _start function go in a new section called “.boot” I’ve defined in the C file using __attribute__((section(".boot"))), then, placing this at the start of .text in the linker script like so
...
.text : ALIGN(4) {
*(.boot)
*(.text)
...
But IDK if this how it should be done.
Thanks in advance :)
That looks like it should work. Have your linker generate a .map file - where does it show your _start symbol? Is it also showing it in the .boot section?
I don’t know what a .map file is, will look into that. This does work, when I
objdumpit _start is at 0x0. But I’m curious if there is a better solution, I’d like to learn how it’s properly done.That’s generally how it’s done.
Oh I see, many thanks.

