From b4de3c561ecfdd7f578115bae3544cc0d8d38fcf Mon Sep 17 00:00:00 2001 From: Tim Hutt Date: Fri, 6 Dec 2024 17:15:00 +0000 Subject: [PATCH] Add explicit note about PTE bits in non-leaf nodes Explicitly say that they are still reserved in non-leaf nodes. This matches the behaviour for Svpmbt for example (and I copied some of the text from there). --- src/cheri-pte-ext.adoc | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/src/cheri-pte-ext.adoc b/src/cheri-pte-ext.adoc index 171b4662..ce8b05d4 100644 --- a/src/cheri-pte-ext.adoc +++ b/src/cheri-pte-ext.adoc @@ -71,7 +71,9 @@ The page table entry format remains unchanged for Sv32. However, two new bits, Capability Write (CW) and Capability Read Generation (CRG), are added to leaf PTEs in Sv39, Sv48 and Sv57 as shown in xref:sv39pte[xrefstyle=short], xref:sv48pte[xrefstyle=short] and -xref:sv57pte[xrefstyle=short] respectively. +xref:sv57pte[xrefstyle=short] respectively. For non-leaf PTEs these bits +remain reserved and must be cleared by software for forward compatibility, +or else a page-fault exception is raised. .Sv39 page table entry [#sv39pte]