[PATCH v5 0/2] Two-stagged initial page table setup

[Anup Patel]

This patchset implements two-stagged initial page table setup using fixmap
to avoid mapping non-existent RAM and also reduce high_memory consumed by
initial page tables.

The patchset is based on Linux-5.2-rc3 and tested on SiFive Unleashed board
and QEMU virt machine.

These patches can be found in riscv_setup_vm_v5 branch of
https//github.com/avpatel/linux.git

Changes since v4:
- Added dtb_early_va which points to DTB for early parsing

Changes since v3:
- Changed patch series subject.
- Dropped PATCH1 because it's already merged
- Dropped PATCH3 because trampoline page table handles a corner case
  for 32bit systems where load address range overlaps kernel virtual
  address range
- Revamped PATCH for 4K aligned booting into two-stagged initial page
  table setup

Changes since v2:
- Dropped PATCH2 because we have separate fix for Linux-5.1-rcX
- Moved PATCH5 to PATCH2
- Moved PATCH4 to PATCH3
- The "Booting kernel from any 4KB aligned address" is now PATCH4

Changes since v1:
- Add kconfig option BOOT_PAGE_ALIGNED to enable 4KB aligned booting
- Improved initial page table setup code to select best/biggest
  possible mapping size based on load address alignment
- Added PATCH4 to remove redundant trampoline page table
- Added PATCH5 to fix memory reservation in setup_bootmem()

Anup Patel (2):
  RISC-V: Fix memory reservation in setup_bootmem()
  RISC-V: Setup initial page tables in two stages

 arch/riscv/include/asm/fixmap.h     |   5 +
 arch/riscv/include/asm/pgtable-64.h |   5 +
 arch/riscv/include/asm/pgtable.h    |   8 +
 arch/riscv/kernel/head.S            |  17 +-
 arch/riscv/kernel/setup.c           |   6 +-
 arch/riscv/mm/init.c                | 331 ++++++++++++++++++++++------
 6 files changed, 292 insertions(+), 80 deletions(-)

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2.17.1