diff options
Diffstat (limited to 'kernel/boot/linker.ld')
-rw-r--r-- | kernel/boot/linker.ld | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/kernel/boot/linker.ld b/kernel/boot/linker.ld new file mode 100644 index 0000000..c90ef51 --- /dev/null +++ b/kernel/boot/linker.ld @@ -0,0 +1,70 @@ +/* + * CMOS + * Copyright (C) 2024-2025 Raghuram Subramani <raghus2247@gmail.com> + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +/* The bootloader will look at this image and start execution at the symbol + designated as the entry point. */ +ENTRY(_start) + +/* Tell where the various sections of the object files will be put in the final + kernel image. */ +SECTIONS +{ + /* It used to be universally recommended to use 1M as a start offset, + as it was effectively guaranteed to be available under BIOS systems. + However, UEFI has made things more complicated, and experimental data + strongly suggests that 2M is a safer place to load. In 2016, a new + feature was introduced to the multiboot2 spec to inform bootloaders + that a kernel can be loaded anywhere within a range of addresses and + will be able to relocate itself to run from such a loader-selected + address, in order to give the loader freedom in selecting a span of + memory which is verified to be available by the firmware, in order to + work around this issue. This does not use that feature, so 2M was + chosen as a safer option than the traditional 1M. */ + . = 2M; + + /* First put the multiboot header, as it is required to be put very early + in the image or the bootloader won't recognize the file format. + Next we'll put the .text section. */ + .text : ALIGN(4K) + { + *(.multiboot) + *(.text) + } + + /* Read-only data. */ + .rodata : ALIGN(4K) + { + *(.rodata) + } + + /* Read-write data (initialized) */ + .data : ALIGN(4K) + { + *(.data) + } + + /* Read-write data (uninitialized) and stack */ + .bss : ALIGN(4K) + { + *(COMMON) + *(.bss) + } + + /* The compiler may produce other sections, by default it will put them in + a segment with the same name. Simply add stuff here as needed. */ +} |