PMP tests assume 4-byte granularity

[marcfedorow]

#577 is just a special case of this problem.
Tests that check NA4 / NAPOT and do not set 'X' flag just trap and never finish because nothing is allowed to execute from the region that contains the test's code.
Still, other tests' signatures don't match because of the wrong accumptions (i.e. 4-byte granularity).

[allenjbaum]

I agree. The tests are being rewritten to take a granularity variable (currently from the DUT specific RVMODEL_BOOT macro, I believe. It will default to granularity of 4B if not defined in that macro.

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On Wed, Dec 18, 2024 at 7:26 AM marcfedorow ***@***.***> wrote: #577 <#577> is just a special case of this problem. Tests that check NA4 / NAPOT and do not set 'X' flag just trap and never finish because nothing is allowed to execute from the region that contains the test's code. Still, other tests' signatures don't match because of the wrong accumptions (i.e. 4-byte granularity). — Reply to this email directly, view it on GitHub <#580>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AHPXVJQOB7C7HU5CHDRW24L2GGH2PAVCNFSM6AAAAABT26TWZWVHI2DSMVQWIX3LMV43ASLTON2WKOZSG42DQMJRGU2TSMI> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[marcfedorow]

I believe that granularity should be checked by software.
RISC-V priv spec says:

Software may determine the PMP granularity by writing zero to pmp0cfg, then writing all ones
to pmpaddr0, then reading back pmpaddr0. If G is the index of the least-significant bit set, the
PMP granularity is 2^(G+2) bytes

[allenjbaum]

The granularity can be checked by SW, but the tests don't need to write & read it (except to verify that it matches what is claimed). The tests can be compiled to match the granularity, and don't need case statements to do different things for different granularity. Yes, we could do that, but it's much simpler to write tests that compile for the supported config (it's pretty much just a few of lines of code).

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On Fri, Dec 20, 2024 at 6:26 AM marcfedorow ***@***.***> wrote: I believe that granularity should be checked by software. RISC-V priv spec says: Software may determine the PMP granularity by writing zero to pmp0cfg, then writing all ones to pmpaddr0, then reading back pmpaddr0. If G is the index of the least-significant bit set, the PMP granularity is 2^(G+2) bytes — Reply to this email directly, view it on GitHub <#580 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AHPXVJUXP7VFKJUVFFYTXET2GQSKDAVCNFSM6AAAAABT26TWZWVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDKNJXGEYTMOBZGA> . You are receiving this because you commented.Message ID: ***@***.***>