From bd13f8c4045cab4f63e85911936c8c5ae188002e Mon Sep 17 00:00:00 2001 From: Tariq Kurd Date: Wed, 18 Dec 2024 17:31:56 +0000 Subject: [PATCH] clarify element zero exceptions for FoF loads (#487) --- src/vector-integration.adoc | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/src/vector-integration.adoc b/src/vector-integration.adoc index ef322be9..40c93c24 100644 --- a/src/vector-integration.adoc +++ b/src/vector-integration.adoc @@ -26,11 +26,7 @@ _no_ CHERI fault will be taken. This is consistent with other exceptions such as page faults which are only taken on _active_ elements. -In the case of fault-only-first loads, only the first element will cause a CHERI -length violation. If a later element causes a length violation, then it will be -treated the same way as a page fault and vl will be reduced. -All other CHERI exceptions, such as tag and permission violations are checked on -the first element, and so will be taken as expected. +In the case of fault-only-first loads, a trap caused by a CHERI exception will only be taken if it caused by element 0 (and then only if element 0 is active). If another active element causes a CHERI exception then it is treated the same way as other exceptions, the trap is not taken and instead vl is reduced. NOTE: Indexed loads in {cheri_cap_mode_name} check the bounds of every access against the authority capability in `cs1`. Therefore the approach of having a zero base