[PATCH v3 0/4] Boot RISC-V kernel from any 4KB aligned address

From: Anup Patel
Date: Mon Mar 25 2019 - 05:23:04 EST

This patchset primarily extends initial page table setup using fixmap
to boot Linux RISC-V kernel (64bit and 32bit) from any 4KB aligned address.

We also add 32bit defconfig to allow people to try 32bit Linux RISC-V
kernel as well.

The patchset is based on Linux-5.1-rc2 and tested on SiFive Unleashed
board and QEMU virt machine.

It can also be found in riscv_setup_vm_v3 branch of

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 (4):
RISC-V: Add separate defconfig for 32bit systems
RISC-V: Fix memory reservation in setup_bootmem()
RISC-V: Remove redundant trampoline page table
RISC-V: Allow booting kernel from any 4KB aligned address

arch/riscv/Kconfig | 12 +
arch/riscv/configs/rv32_defconfig | 84 +++++++
arch/riscv/include/asm/fixmap.h | 5 +
arch/riscv/include/asm/pgtable-64.h | 5 +
arch/riscv/include/asm/pgtable.h | 5 +
arch/riscv/kernel/head.S | 14 +-
arch/riscv/kernel/setup.c | 4 +-
arch/riscv/mm/init.c | 376 +++++++++++++++++++++++-----
8 files changed, 430 insertions(+), 75 deletions(-)
create mode 100644 arch/riscv/configs/rv32_defconfig