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Diffstat (limited to 'src/supervisor.tex')
| -rw-r--r-- | src/supervisor.tex | 13 |
1 files changed, 5 insertions, 8 deletions
diff --git a/src/supervisor.tex b/src/supervisor.tex index f718ecc..e426beb 100644 --- a/src/supervisor.tex +++ b/src/supervisor.tex @@ -1812,13 +1812,10 @@ root page table is stored in the {\tt satp} register's PPN field. The PTE format for Sv39 is shown in Figure~\ref{sv39pte}. Bits 9--0 have the same meaning as for Sv32. -The N bit indicates that the page represents a -naturally-aligned power-of-two range of contiguous translations, as defined in -the Svnapot extension in Chapter~\ref{svnapot}. - -Bits 62--54 are reserved -for future standard use and must be zeroed by software for forward compatibility. -If any of these bits are set, a page-fault exception is raised. +Bit 63 is reserved for use by the Svnapot extension in +Chapter~\ref{svnapot}. Bits 62--54 are reserved for future standard use. All +of these bits must be zeroed by software for forward compatibility. If any of +these bits are set, a page-fault exception is raised. \begin{commentary} We reserved several PTE bits for a possible extension that improves @@ -2124,7 +2121,7 @@ equals 8. \chapter{``Svnapot'' Standard Extension for NAPOT Translation Contiguity, Version 0.1} \label{svnapot} -In Sv39, Sv48, and Sv57, when a PTE has N=1, the PTE represents a +In Sv39, Sv48, and Sv57, when Svnapot is enabled and a PTE has N=1, the PTE represents a translation that is part of a range of contiguous virtual-to-physical translations with the same values for PTE bits 5--0. Such ranges must be of a naturally aligned power-of-2 (NAPOT) granularity larger than the base page |