Use NAPOT PMP to cover the entire physical address space #154
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The current PMP setting uses TOR regions, which does not cover the end of the memory (spec: If PMP entry 0’s A field is set to TOR, zero is used for the lower bound, and so it matches any address y < pmpaddr0). Proposed new NAPOT PMP covers every byte of physical memory in the 56-bit physical address space. Quote from Andrew: you need to use a NAPOT PMP if you want to grant permissions to the entire address space. Relevant discussions: * riscv/riscv-isa-manual#138 * https://groups.google.com/a/groups.riscv.org/g/sw-dev/c/pn9ZCf0O65c/m/tnLTjg74CgAJ
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The current PMP setting uses TOR regions, which does not cover the end of the memory (spec: If PMP entry 0’s A field is set to TOR, zero is used for the lower bound, and so it matches any address y < pmpaddr0).
Proposed new NAPOT PMP covers every byte of physical memory in the 56-bit physical address space.
Quote from Andrew: you need to use a NAPOT PMP if you want to grant permissions to the entire address space.
Relevant discussions: