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Fix incorrect checks in capChecksMem.

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These checks were broken in several ways:

1) a missing 'else' inverted the priority of PermitStoreViolation vs. PermitStore[Local]Cap exceptions
2) another missing 'else' inverted the priority of PermitStoreCap and PermitStoreLocalCap exceptions
3) No store checks were performed when mem_func == Amo because of the preceding if clause for loads

I decided to flatten the nested if statements by pulling out the conditions into boolean local variables. Hopefully this makes it clearer (as well as fixing the bugs).
This commit is contained in:
Robert Norton
2021-08-04 17:52:56 +01:00
committed by Robert Norton
parent b811cdb967
commit 5b23f4cea0
1 changed files with 16 additions and 16 deletions
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32
src_Core/RISCY_OOO/procs/lib/Exec.bsv
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@@ -107,26 +107,26 @@ function Maybe#(CSR_XCapCause) capChecksMem(CapPipe auth, CapPipe data, CapCheck
endcase
, cheri_exc_code: e});
Maybe#(CSR_XCapCause) result = Invalid;
match {.isLoad, .isStore} = case (mem_func)
Ld, Lr: tuple2(True, False);
St, Sc: tuple2(False, True);
Amo: tuple2(True, True);
endcase;
Bool storeValidCap = isStore && isValidCap(data) && byteOrTagEn == DataMemAccess(replicate(True));
if (!isValidCap(auth))
result = eAuth(cheriExcTagViolation);
else if (getKind(auth) != UNSEALED)
result = eAuth(cheriExcSealViolation);
else if (mem_func == Ld || mem_func == Lr || mem_func == Amo) begin
if (!getHardPerms(auth).permitLoad)
result = eAuth(cheriExcPermitRViolation);
else if (!getHardPerms(auth).permitLoadCap && byteOrTagEn == TagMemAccess)
result = eAuth(cheriExcPermitRCapViolation);
end
else if (mem_func == St || mem_func == Sc || mem_func == Amo) begin
if (!getHardPerms(auth).permitStore)
result = eAuth(cheriExcPermitWViolation);
if (isValidCap(data) && byteOrTagEn == DataMemAccess(replicate(True))) begin
if (!getHardPerms(auth).permitStoreCap)
result = eAuth(cheriExcPermitWCapViolation);
if (!getHardPerms(auth).permitStoreLocalCap && getHardPerms(data).global)
result = eAuth(cheriExcPermitWLocalCapViolation);
end
end
else if (isLoad && !getHardPerms(auth).permitLoad)
result = eAuth(cheriExcPermitRViolation);
else if (isLoad && !getHardPerms(auth).permitLoadCap && byteOrTagEn == TagMemAccess)
result = eAuth(cheriExcPermitRCapViolation);
else if (isStore && !getHardPerms(auth).permitStore)
result = eAuth(cheriExcPermitWViolation);
else if (storeValidCap && !getHardPerms(auth).permitStoreCap)
result = eAuth(cheriExcPermitWCapViolation);
else if (storeValidCap && !getHardPerms(auth).permitStoreLocalCap && getHardPerms(data).global)
result = eAuth(cheriExcPermitWLocalCapViolation);
return result;
endfunction