D1.1 Exception levelsARM052019-3-17
D1.1 Exception levels ARM05 2019-3-17 6
AArch32->AArch64transitionTrustedApp2TrustedApp1App1App2App2ELOApp1++++-+++GuestOperatingSystem1GuestOperatingSystem2SecureWorld OsEL1AArch64->AArch32transitionAArch64:separateprivilege levelsVirtualMachineMonitor(VMM)orAArch32:EL2same privilege levelHypervisor+.+++++++++++++++++++++++++++++++++++++++++++++++EL3(TrustZone)MonitorExceptionLevelArchitectureELO forunprivileged application executionEL1 for privileged OS executionEL2forhypervisor,virtualizationof Non-secure stateEL3 for secure monitor,which switches between Secure and Non-secure stateEL1-EL3(exceptforELO)havetheirown translation regime & controlregistersARM052019-3-17
7 ARM05 2019-3-17 Exception Level Architecture EL0 for unprivileged application execution EL1 for privileged OS execution EL2 for hypervisor, virtualization of Non-secure state EL3 for secure monitor, which switches between Secure and Non-secure state EL1-EL3 (except for EL0) have their own translation regime & control registers
AArch32->AArch64transitionTrustedApp2TrustedApp1App1App2App1App2ELOGuestOperatingSystem1GuestOperatingSystem2SecureWorld OsEL1AArch64->AArch32transitionAArch64:separateprivilegelevelsVirtualMachineMonitor(VMM)orAArch32:EL2same privilege levelHypervisor++++++++++++++++++++++++++.+++++++++++++++.EL3(TrustZone)MonitorExecutionLevel TransitionOn taking exception:Exceptionlevel increase or remainIt is called the target Exception levelELo can'tbe an target Exception levelOn returning from exception:Exception level decrease or remainARM052019-3-17
8 ARM05 2019-3-17 Execution Level Transition On taking exception: Exception level increase or remain It is called the target Exception level EL0 can’t be an target Exception level On returning from exception: Exception level decrease or remain
AArch32->AArch64transitionTrustedApp2TrustedApp1App1App2App2ELOApp1GuestOperatingSystem1GuestOperatingSystem2SecureWorld OsEL1AArch64->AArch32transitionAArch64:separateprivilege levelsVirtualMachineMonitor(VMM)orAArch32:EL2sameprivilege leveHypervisor++++++++++++++++++++++++++++++++++++++++++.EL3(TrustZone)MonitorExceptionlevelResourcesResources for current Exception level and current Security stateResources for low Exception levels and current Security stateFor example,PE at EL3 can access all resources at all Exceptionlevels,forbothSecuritystatesARM052019-3-17
9 ARM05 2019-3-17 Exception level Resources Resources for current Exception level and current Security state Resources for low Exception levels and current Security state For example, PE at EL3 can access all resources at all Exception levels, for both Security states
D1.2Exceptionterms10D1.2.1Precise&lmprecise exceptions D1.2.2 Sync&Async exceptionsARM052019-3-17
D1.2 Exception terms ARM05 2019-3-17 10 D1.2.1 Precise&Imprecise exceptions D1.2.2 Sync&Async exceptions