rtl: el2_dec_pmp_ctl: Prevent using shared regions, while MML is unset - #527
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tmichalak wants to merge 2 commits into
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rtl: el2_dec_pmp_ctl: Prevent using shared regions, while MML is unset#527tmichalak wants to merge 2 commits into
tmichalak wants to merge 2 commits into
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The rationale behind this change, is that the RISC-V specification, explicitly marks the regions with the attributes R=0, W=1, as reserved, even if SMEPMP extension is implemented, as long as MML=0. To configure such regions, MML needs to be set. To configure Locked regions, it is possible to additionally use RLB, and reset it at the end of PMP configuration. Since PMP registers are WARL (Write Any, Read Legal), if the config is reserved, it should not be read - so we clear the reserved bits. Signed-off-by: Mateusz Karlic <mkarlic@antmicro.com>
Also fix typo `MML -> RLB` in one of the failure logs. Signed-off-by: Mateusz Karlic <mkarlic@antmicro.com>
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The rationale behind this change, is that the RISC-V specification, explicitly marks the regions with the attributes R=0, W=1, as reserved, even if SMEPMP extension is implemented, as long as MML=0. To configure such regions, MML needs to be set. To configure Locked regions, it is possible to additionally use RLB, and reset it at the end of PMP configuration.
Since PMP registers are WARL (Write Any, Read Legal), if the config is reserved, it should not be read - so we clear the reserved bits.
Added tests to cover the above conditions.