[PATCH v6 0/5] LoongArch: Add kernel relocation and KASLR support

[Youling Tang]

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

Tested the kernel images built with new toolchain (Binutils-2.40 + patched
GCC-12.2) and old toolchain (kernel.org cross toolchain [1]) on a
3A5000-7A2000-EVB.

With CONFIG_RANDOMIZE_BASE=y, the results are:

1. first boot, new toolchain:

$ sudo cat /proc/iomem | grep Kernel
  01080000-0189ffff : Kernel code
  018a0000-01deb5ff : Kernel data
  01deb600-01ef6e9f : Kernel bss

2. second boot, new toolchain:

$ sudo cat /proc/iomem | grep Kernel
  012f0000-01b0ffff : Kernel code
  01b10000-0205b5ff : Kernel data
  0205b600-02166e9f : Kernel bss

3. first boot, old toolchain:
  010e0000-018fffff : Kernel code
  01900000-01e591ff : Kernel data
  01e59200-01f56dcf : Kernel bss

4. second boot, old toolchain:
  010b0000-018cffff : Kernel code
  018d0000-01e291ff : Kernel data
  01e29200-01f26dcf : Kernel bss

Changes from v5:
- Fix relocate_la_abs.
- Other minor modifications.

Changes from v4:
- Add la_abs macro implementation.
- Remove patch2 (LoongArch: Use la.pcrel instead of la.abs for exception
  handlers).
- Remove SYS_SUPPORTS_RELOCATABLE.
- Fix do_kaslr.
- Fix compiler warnings.
- Move some declarations and struct definitions to setup.h.

Changes from v3:

- JUMP_LINK_ADDR renamed to JUMP_VIRT_ADDR, and use the way of parameter
  passing.
- Reimplement kernel relocation, when the link address and load address
  are different, realize the effect of adaptive relocation (one of the
  usage scenarios is kdump operation).
- Reimplement KASLR.

Changes from v2:

- Correctly fixup pcaddi12i/ori/lu32i.d/lu52i.d sequence generated by
  GNU as <= 2.39 for la.pcrel.

Changes from v1 to v2:

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

Xi Ruoyao (1):
  LoongArch: Use la.pcrel instead of la.abs when it's trivially possible

Youling Tang (4):
  LoongArch: Add JUMP_VIRT_ADDR macro implementation to avoid using
    la.abs
  LoongArch: Add la_abs macro implementation
  LoongArch: Add support for kernel relocation
  LoongArch: Add support for kernel address space layout randomization
    (KASLR)

 arch/loongarch/Kconfig                  |  31 +++
 arch/loongarch/Makefile                 |   5 +
 arch/loongarch/include/asm/asmmacro.h   |  17 ++
 arch/loongarch/include/asm/setup.h      |  16 ++
 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           |   8 +-
 arch/loongarch/kernel/head.S            |  31 ++-
 arch/loongarch/kernel/relocate.c        | 245 ++++++++++++++++++++++++
 arch/loongarch/kernel/vmlinux.lds.S     |  20 +-
 arch/loongarch/mm/tlbex.S               |  17 +-
 arch/loongarch/power/suspend_asm.S      |   5 +-
 14 files changed, 382 insertions(+), 31 deletions(-)
 create mode 100644 arch/loongarch/kernel/relocate.c

-- 
2.37.3