The CPU first checks the page directory entry for write
or user permissions on a particular page before looking
at the page table entry.
If a region configured all pages to be non user accessible,
and this was changed for a page within it to be accessible,
the PDE would not be updated and any access would still
return a page fault.
The least amount of runtime logic to deal with this is to
indicate at build time that some pages within a region may
be marked writable or user accessible at runtime, and to
pre-set the flags in the page directory entry accordingly.
The driving need for this is the region configuration for
kernel memory, which will have user permissions set at
runtime for stacks and user-configured memory domains.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Verbose output now prints the value of the raw data provided by
soc.c file. The page directories are printed with the correct
address ranges for each required region.
Updated the page table number calculation and also updated other
calculations which use this information.
Signed-off-by: Adithya Baglody <adithya.nagaraj.baglody@intel.com>
It's useful to see what original memory regions were configured
in code via the MMU_BOOT_REGION() macros.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
The script failed on certain corner cases. Whenever the memory region
was falling on the PDE boundary, the glitch was causing incorrect
PTE to be generated.
JIRA: ZEP-2328
Signed-off-by: Adithya Baglody <adithya.nagaraj.baglody@intel.com>
Generates the MMU page tables. This creates a binary output for
the page tables. It takes an binary input which represents the
configuration information needed to generate the page tables.
JIRA:ZEP-2096
Signed-off-by: Adithya Baglody <adithya.nagaraj.baglody@intel.com>
