[PATCH v2 0/5] LoongArch: Add kernel relocation and KASLR support

[Xi Ruoyao]

This patch series to support kernel relocation and KASLR (only 64bit).

I've only tested new toolchains (CONFIG_AS_HAS_EXPLICIT_RELOCS=y)
consisted of Binutils-2.40, and GCC-12.2 heavily patched to support new
relocs.  Unfortunately I've purged my old toolchain installation (because
it contained a buggy GCC-12.1 miscompiling some code).  Please test the
configuration with old toolchain.

Test results with CONFIG_RANDOMIZE_BASE=y on a 3A5000-7A2000-EVB:

First boot:

$ sudo cat /proc/iomem | grep Kernel
  010e0000-018fffff : Kernel code
  01900000-01e4b5ff : Kernel data
  01e4b600-01f56e9f : Kernel bss

Second boot:

$ sudo cat /proc/iomem | grep Kernel
  019a0000-021bffff : Kernel code
  021c0000-0270b5ff : Kernel data
  0270b600-02816e9f : Kernel bss

Changes from v1:

- Relocate the handlers instead of using a trampoline, to avoid
  performance issue on NUMA systems.
- Fix compiler warnings.

Xi Ruoyao (2):
  LoongArch: Use la.pcrel instead of la.abs when it's trivially possible
  LoongArch: Use la.pcrel instead of la.abs for exception handlers

Youling Tang (3):
  LoongArch: Add JUMP_LINK_ADDR macro implementation to avoid using
    la.abs
  LoongArch: Add support for kernel relocation
  LoongArch: Add support for kernel address space layout randomization
    (KASLR)

 arch/loongarch/Kconfig                  |  37 +++++
 arch/loongarch/Makefile                 |   5 +
 arch/loongarch/include/asm/page.h       |   6 +
 arch/loongarch/include/asm/setup.h      |   6 +-
 arch/loongarch/include/asm/stackframe.h |  13 +-
 arch/loongarch/include/asm/uaccess.h    |   1 -
 arch/loongarch/kernel/Makefile          |   2 +
 arch/loongarch/kernel/entry.S           |   2 +-
 arch/loongarch/kernel/genex.S           |  40 ++++-
 arch/loongarch/kernel/head.S            |  30 +++-
 arch/loongarch/kernel/relocate.c        | 211 ++++++++++++++++++++++++
 arch/loongarch/kernel/setup.c           |   3 +
 arch/loongarch/kernel/traps.c           | 138 +++++++++++++---
 arch/loongarch/kernel/vmlinux.lds.S     |  11 +-
 arch/loongarch/mm/tlb.c                 |  23 +--
 arch/loongarch/mm/tlbex.S               |  72 +++++++-
 arch/loongarch/power/suspend_asm.S      |   5 +-
 17 files changed, 543 insertions(+), 62 deletions(-)
 create mode 100644 arch/loongarch/kernel/relocate.c

-- 
2.37.0