linux#

Jun 12, 2023
in arm, linux
6 min read

ADRP & LDR in arm64/kernel primary switch

In linux arm64 kernel, the transition of the PC from the physical address space to the real virtual address space is completed with the last three instructions of head.S after MMU enabled.

    ldr     x8, =__primary_switched
    adrp    x0, KERNEL_START        // __pa(KERNEL_START)
    br      x8                      // executed with the MMU enabled

Nov 14, 2019
in linux, resource
1 min read

Linux Kernel Start Routine

The Linux booting process involves multiple stages and is in many ways similar to the BSD and other Unix-style boot processes, from which it derives. Although the Linux booting process depends very much on the computer architecture, those architectures share similar stages and software components, including system startup, bootloader execution, loading and startup of a Linux kernel image, and execution of various startup scripts and daemons. Those are grouped into 4 steps: system startup, bootloader stage, kernel stage, and init process.

There are many debts waiting to be paid. Lots of work waiting to be done. At the moment I am just collecting some reference material for future study.

Nov 12, 2019
in linux
3 min read

Linux Kernel Image -- vmlinux

The kernel is the core of the Linux system. It is the first component loaded into the memory upon boot up. It provides a user interface that allows us to interact with the operating system and remains in the memory throughout the computer's use.