Commit Graph

4 Commits

Author SHA1 Message Date
Andrew Boie 5e0b55c30e kernel: demote k_mem_map to z_mem_map
Memory mapping, for now, will be a private kernel API
and is not intended to be application-facing at this time.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
2020-09-03 14:24:38 -04:00
Andrew Boie 7d32e9f9a5 mmu: support only identity RAM mapping
We no longer plan to support a split address space with
the kernel in high memory and per-process address spaces.
Because of this, we can simplify some things. System RAM
is now always identity mapped at boot.

We no longer require any virtual-to-physical translation
for page tables, and can remove the dual-mapping logic
from the page table generation script since we won't need
to transition the instruction point off of physical
addresses.

CONFIG_KERNEL_VM_BASE and CONFIG_KERNEL_VM_LIMIT
have been removed. The kernel's address space always
starts at CONFIG_SRAM_BASE_ADDRESS, of a fixed size
specified by CONFIG_KERNEL_VM_SIZE.

Driver MMIOs and other uses of k_mem_map() are still
virtually mapped, and the later introduction of demand
paging will result in only a subset of system RAM being
a fixed identity mapping instead of all of it.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
2020-09-03 14:24:38 -04:00
Andrew Boie e433494f40 kernel: mmu: implement virtual mappings
These will grow downward from CONFIG_KERNEL_VM_LIMIT.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
2020-08-25 15:49:59 -04:00
Andrew Boie 06cf6d27f7 kernel: add k_mem_map() and related defines
This will be the interface for mapping memory in the kernel's
part of the address space, which is guaranteed to be persistent
regardless of what thread is scheduled.

Further code for specifically managing virtual memory will end up in
kernel/mmu.c.

Further defintions for memory management in general will end up
in sys/mem_manage.h.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
2020-07-17 11:38:18 +02:00