• Achin Gupta's avatar
    Remove coherent stack usage from the cold boot path · 754a2b7a
    Achin Gupta authored
    This patch reworks the cold boot path across the BL1, BL2, BL3-1 and BL3-2 boot
    loader stages to not use stacks allocated in coherent memory for early platform
    setup and enabling the MMU. Stacks allocated in normal memory are used instead.
    
    Attributes for stack memory change from nGnRnE when the MMU is disabled to
    Normal WBWA Inner-shareable when the MMU and data cache are enabled. It is
    possible for the CPU to read stale stack memory after the MMU is enabled from
    another CPUs cache. Hence, it is unsafe to turn on the MMU and data cache while
    using normal stacks when multiple CPUs are a part of the same coherency
    domain. It is safe to do so in the cold boot path as only the primary cpu
    executes it. The secondary cpus are in a quiescent state.
    
    This patch does not remove the allocation of coherent stack memory. That is done
    in a subsequent patch.
    
    Change-Id: I12c80b7c7ab23506d425c5b3a8a7de693498f830
    754a2b7a
bl1_entrypoint.S 5.6 KB