A common usage model is application code running at EL0, with a rich Operating System (OS) such as Linux running at EL1. EL2 may be used by a hypervisor, with EL3 used by firmware and security gateway code.

Jan 7, 2023 · In first ARM core, only the equivalent of EL0 and EL1 were defined. The difference is mostly that EL0 does not have access to system registers (Exceptions, program the MMU, etc.) which are reserved to EL1.

A common usage model has application code running at EL0, with an operating system running at EL1. EL2 is used by a hypervisor, with EL3 being reserved by low-level firmware and security code.

In general, you would want your application code to run at a lower level so that it cannot corrupt system settings, maliciously or otherwise. Switching between levels is performed by the ERET exception return instruction. Extend the example to make …

Mar 20, 2022 · armv8-a系列定义了一系列的异常等级，从el0到el3，下面具体说明其含义： eln中，随着n的增加，软件的执行权限也相应的增加； el0被称为无特权执行； el2提供了对虚拟化的支持; el3提供了安全状态切换功能（安全状态与非安装状态之间的切换）

EL1 (Exception Level 1): The primary level for running the operating system kernel and most user applications. It acts as the host, managing resources for applications in EL0. EL2 (Exception Level 2): An optional level used for specific purposes like secure co-processor functions or virtualization.

Oct 28, 2023 · armv8 架构将异常等级和软件的执行权限关联起来，总共定义了4个异常等级：el0，el1，el2，el3。el0被称之为无特权的异常等级，通常用于用户程序的执行。执行在用户空间，可称之为用户模式。el1常用于操作系统，可称之为管理员模式。

Jan 4, 2021 · EL1 is the level that priveldged parts of the OS kernels use, so for example, Linux Kernel code will run with EL1 priveledges. EL0 is the most unprivledged level and therefore that’s where the most unpriviledged code runs (userspace application, userspace drivers, etc). As I mentioned above not all levels are required.

el0 是最低权限的异常等级，通常用来运行用户态。 对于同步异常 同步异常可以在当前异常等级里处理，例如在内核（ EL1 ）中发生缺页错误，通常不会改变异常等级。

处理程序代码可以从使用 sp_eln 切换到 sp_el0。 例如，sp_el1 可能指向一块内存，其中包含一个内核可以保证始终有效的小堆栈。 sp_el0 可能指向更大的内核任务堆栈，但不能保证不会溢出。 这种切换是通过写入 [spsel] 位来控制的，如下