move kernel virtual address space to upper addresses

* i386/i386/vm_param.h: adjust constants to the new kernel map
  - the boothdr.S code already sets up a temporary map to higher
    addresses, so we can use INIT_VM_MIN_KERNEL_ADDRESS as in xen
  - increase the kernel map size to accomodate for bigger structures
    and more memory
  - adjust kernel max address and directmap limit
* i386/i386at/biosmem.c: enable directmap check also on x86_64
* i386/include/mach/i386/vm_param.h: increase user virtual memory
  limit as it's not conflicting with the kernel's anymore
* i386/intel/pmap.h: adjust lin2pdenum_cont() and INTEL_PTE_PFN to the
  new kernel map
* x86_64/Makefrag.am: change KERNEL_MAP_BASE to be above 4G, and
  according to mcmodel=kernel. This will allow to use the full memory
  address space.
Message-Id: <20230212172818.1511405-10-luca@orpolo.org>

1 files changed, 6 insertions, 6 deletions

diff --git a/x86_64/Makefrag.am b/x86_64/Makefrag.am
index 03b1eca7..d3735890 100644
--- a/x86_64/Makefrag.am
+++ b/x86_64/Makefrag.am
@@ -186,12 +186,12 @@ include_mach_x86_64_HEADERS = \
 #
 
 if PLATFORM_at
-# This should probably be 0xffffffff80000000 for mcmodel=kernel, but let's try
-# to stay in the first 8G first, otherwise we have to fix the pmap module to
-# actually use the l4 page level
-#KERNEL_MAP_BASE=0x100000000
-# but for nor try with < 4G, otherwise we have linker errors
-KERNEL_MAP_BASE=0x40000000
+# For now simply keep all the kernel virtual space in the last 2G.
+# We could use a more elaborate schema if needed (e.g. reserving a
+# larger area for directmap or the kernel heap)), I think only the
+# test/bss/data sections need to be placed here kere because of
+# -mcmodel=kernel
+KERNEL_MAP_BASE=0xffffffff80000000
 gnumach_LINKFLAGS += \
 	--defsym _START_MAP=$(_START_MAP) \
 	--defsym _START=$(_START_MAP) \