EL0 / EL1

ARM's privilege tiers: EL0 is ordinary app code, EL1 is the operating-system kernel.

ARM CPUs run code at Exception Levels, where a higher number means more privilege. EL0 is userspace — where normal applications live with limited access — and EL1 is the kernel, which can touch hardware and manage memory. Crossing between them, via faults or syscalls, is tightly controlled for safety.

See also

faultA CPU exception raised when a program does something illegal, like touching memory it shouldn't.
execveThe specific system call that loads a new program and starts running it in place of the current one.
Device Tree Blob (DTB)A compact file that tells the operating system what hardware is present, since the CPU can't just discover it.
ELFThe standard file format for executable programs and libraries on Linux and similar systems.

Referenced by

Device Tree Blob (DTB) · DTB · ELF · execve · fault