rtl: el2_dec_pmp_ctl: Prevent using shared regions, while MML is unset - #522
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rtl: el2_dec_pmp_ctl: Prevent using shared regions, while MML is unset#522MateuszKarlic wants to merge 1 commit into
MateuszKarlic wants to merge 1 commit 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>
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Superseded by #527. Closing. |
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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 ifSMEPMPextension is implemented, as long asMML=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.