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doc: pmp granularity equals to 8-byte (#2572)

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André Sintzoff 2024-11-04 09:27:23 +01:00 • committed by GitHub
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12
docs/riscv-isa/src/machine.adoc
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@ -4343,13 +4343,11 @@ back to NAPOT.
endif::[]
ifdef::archi-CVA6[]
[{ohg-config}] Although the PMP mechanism supports regions as small as four bytes,
platforms may specify coarser PMP regions. In general, the PMP grain is
latexmath:[$2^{G+2}$] bytes and must be the same across all PMP regions.
When latexmath:[$G \geq 1$] and
latexmath:[${\tt pmpcfg}_i$].A[1] is clear, i.e. the mode is OFF or TOR,
then bits latexmath:[${\tt pmpaddr}_i$][G-1:0] read as all zeros. Bits
latexmath:[${\tt pmpaddr}_i$][G-1:0] do not affect the TOR address-matching
[{ohg-config}] The PMP grain is 8 bytes (latexmath:[$2^{G+2}$] with G = 1)
and must be the same across all PMP regions.
As latexmath:[${\tt pmpcfg}_i$].A[1] is always clear, i.e. the mode is OFF or TOR,
then bit latexmath:[${\tt pmpaddr}_i$][0] read as zero. Bit
latexmath:[${\tt pmpaddr}_i$][0] does not affect the TOR address-matching
logic.
endif::[]