[U-Boot] [PATCH v6 0/2] armv8: Support loading 32-bit OS in AArch32 execution state

[Alison Wang]

This series is to support loading a 32-bit OS, the execution state will change from
AArch64 to AArch32 when jumping to kernel. The architecture information will be got
through checking FIT image, then U-Boot will load 32-bit OS or 64-bit OS automatically.

Spin-table method is used for secondary cores to load 32-bit OS. The architecture
information will be got through checking FIT image and saved in the os_arch element
of spin-table, then the secondary cores will check os_arch and jump to 32-bit OS or
64-bit OS automatically.

---------------------------------------
Changes in v6:
- Modified armv8_switch_to_el1(). It will always jump to ep when switching to AArch64 or AArch32 modes.
- Make other platforms compatible with the new armv8_switch_to_el2() and armv8_switch_to_el1().

Changes in v5:
- Modified armv8_switch_to_el2(). It will always jump to ep when switching to AArch64 or AArch32 modes.
- Make secondary_switch_to_el2() always jump to ep when switching to AArch64 or AArch32 modes.

Changes in v4:
- Correct config ARM64_SUPPORT_AARCH32.
- Omit arch and ftaddr arguments.
- Rename "xreg5" to "tmp".
- Use xxx_RES1 to combine all RES1 fields in xxx register.
- Use an immediate cmp directly.
- Use #ifdef for CONFIG_ARM64_SUPPORT_AARCH32.

Changes in v3:
- Comments the functions and the arguments.
- Rename the real parameters.
- Use the macros instead of the magic values.
- Remove the redundant codes.
- Clean up all of the mess in boot_jump_linux().
- Add CONFIG_ARM64_SUPPORT_AARCH32 to detect for some ARM64 system doesn't support AArch32 state.
- Adjust the arguments for armv8_switch_to_el2_m and armv8_switch_to_el1_m.

Changes in v2:
- armv8_switch_to_el2_aarch32() is removed. armv8_switch_to_el2_m is used
  to switch to AArch64 EL2 or AArch32 Hyp.
- armv8_switch_to_el1_aarch32() is removed. armv8_switch_to_el1_m is used
  to switch to AArch64 EL1 or AArch32 SVC.
- Support to call armv8_switch_to_el2_m and armv8_switch_to_el1_m.

----------------------------------------------------------------
Alison Wang (2):
      armv8: Support loading 32-bit OS in AArch32 execution state
      armv8: fsl-layerscape: SMP support for loading 32-bit OS

 arch/arm/Kconfig                              |   6 ++
 arch/arm/cpu/armv8/fsl-layerscape/lowlevel.S  |  61 ++++++++++++---
 arch/arm/cpu/armv8/fsl-layerscape/mp.c        |  10 +++
 arch/arm/cpu/armv8/start.S                    |   8 ++
 arch/arm/cpu/armv8/transition.S               |   8 +-
 arch/arm/include/asm/arch-fsl-layerscape/mp.h |   6 ++
 arch/arm/include/asm/macro.h                  | 176 +++++++++++++++++++++++++++++++++-----------
 arch/arm/include/asm/system.h                 | 119 +++++++++++++++++++++++++++++-
 arch/arm/lib/bootm.c                          |  45 +++++++++--
 arch/arm/mach-rmobile/lowlevel_init_gen3.S    |   9 ++-
 common/image-fit.c                            |  19 ++++-
 11 files changed, 401 insertions(+), 66 deletions(-)