[v2,0/7] Unflattening and relocation of host device tree

Message

Oleksii Kurochko Dec. 11, 2024, 5:27 p.m. UTC

The current patch series introduces the relocation of the host device tree file
to free up low memory and also it is expected that discard_initial_modules()
will be called sooner or later, it will discard the FDT boot module,
and remove_early_mappings() will destroy the early mappings.

In addition to relocation, unflattening is introduced to create the tree of
struct device_node for the host device tree.

To implement this, several things have been introduced:
 - destroy_xen_mappings() function, which removes page mappings from Xen's
   page tables. This is necessary for clear_fixmap().
 - {set,clear}_fixmap() functions to manage mappings in the fixmap region,
   which are expected to be used in copy_from_paddr() to copy the FDT to Xen's
   heap.
 - Introduce new config CONFIG_QEMU which is going to be used to cover changes
   connected to QEMU virtual board. It will be used during introduction of stubs
   for clean_and_invalidate_dcache_va_range() and clean_dcache_va_range(),
   which are expected to be used in copy_from_paddr() and flush_page_to_ram(),
   which in turn are expected to be used during the call to xvmalloc_array() in
   relocate_fdt().
   In case of QEMU cached related functions are implemented as returning 0 as
   QEMU doesn't model cache ( and so CMO extensions ). For others cases, it is
   introduced as -ENOSUPP as h/w could support CMO extension ( or hardware
   specific insertions ) and it will need to update implementation of the
   mentioned functions.
 - The introduction of copy_from_paddr() to copy the FDT to an address
   allocated in Xen's heap.

---
Changes in v2:
 - Update the cover letter.
 - Introduce new patch with aligning of upper bounds in the layout table in
   config.h with the definitions below which are inclusive.
 - Other changes please look at the specific patch.
---

Oleksii Kurochko (7):
  xen/riscv: update layout table in config.h
  xen/riscv: add destroy_xen_mappings() to remove mappings in Xen page
    tables
  xen/riscv: reorder includes in asm/page.h alphabetically
  xen/riscv: add {set,clear}_fixmap() functions for managing fixmap
    entries
  xen/riscv: implement data and instruction cache operations
  xen/riscv: implement prereq for DTB relocation
  xen/riscv: relocating and unflattening host device tree

 xen/arch/riscv/Kconfig                  |  2 +
 xen/arch/riscv/configs/tiny64_defconfig |  1 +
 xen/arch/riscv/include/asm/config.h     | 12 +++---
 xen/arch/riscv/include/asm/fixmap.h     |  5 +++
 xen/arch/riscv/include/asm/mm.h         |  8 +++-
 xen/arch/riscv/include/asm/page.h       | 34 +++++++++++++--
 xen/arch/riscv/include/asm/setup.h      |  4 ++
 xen/arch/riscv/mm.c                     |  6 ---
 xen/arch/riscv/platforms/Kconfig        |  5 +++
 xen/arch/riscv/pt.c                     | 25 +++++++++++
 xen/arch/riscv/setup.c                  | 57 ++++++++++++++++++++++++-
 11 files changed, 139 insertions(+), 20 deletions(-)
 create mode 100644 xen/arch/riscv/platforms/Kconfig