tree 7d5bfeb30f5e178f05b932c20d64f2d9fd98583f
parent 31e323cca9d5c8afd372976c35a5d46192f540d1
author Ian Campbell <ian.campbell@citrix.com> 1288798341 +0000
committer Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> 1291079273 -0800

xen: x86/32: perform initial startup on initial_page_table

Only make swapper_pg_dir readonly and pinned when generic x86 architecture code
(which also starts on initial_page_table) switches to it.  This helps ensure
that the generic setup paths work on Xen unmodified. In particular
clone_pgd_range writes directly to the destination pgd entries and is used to
initialise swapper_pg_dir so we need to ensure that it remains writeable until
the last possible moment during bring up.

This is complicated slightly by the need to avoid sharing kernel PMD entries
when running under Xen, therefore the Xen implementation must make a copy of
the kernel PMD (which is otherwise referred to by both intial_page_table and
swapper_pg_dir) before switching to swapper_pg_dir.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>