[U-Boot] [PATCH v8 0/3] armv8: Support loading 32-bit OS in AArch32 execution state

[Ryan Harkin]

Hi Alison,

On 10 November 2016 at 02:49, Alison Wang <b18965 at freescale.com> wrote:
> 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.
>
> PSCI method can also be used for secondary cores to load 32-bit OS.
> As PSCI and secure monitor firmware framework are enabled, loading 32-bit OS is supported in such case. The default target exception level returned to U-Boot is EL2, so the corresponding work to switch to AArch32 EL2 and jump to 32-bit OS are done in U-Boot and secure firmware together.
>
> ---------------------------------------
> Changes in v8:
> - Fix the issue when U-Boot is running in EL2 or EL1.

Thanks for sticking with this.  Great news: it works for my setup.

I tested booting an arm64 kernel on FVP Foundation and AEMv8 modes and
on Juno R0, R1 and R2.  I also tested and Versatile Express TC2 can
still load it's Aarch32 kernel.

I didn't test running an Aarch32 kernel or any of the new
functionality on my ARMv8 platforms.

But I checked and the patches are bisect-able on my ARMv8 platforms.

Tested-by: Ryan Harkin <ryan.harkin at linaro.org>


> - Support loading 32-bit OS with PSCI enabled.
>
> Changes in v7:
> - Move the call for armv8_switch_to_el2_m into the first patch.
>
> 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().
> - Make secondary_switch_to_el1() always jump to ep when switching to AArch64 or AArch32 modes.
>
> 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 (3):
>       armv8: Support loading 32-bit OS in AArch32 execution state
>       armv8: fsl-layerscape: SMP support for loading 32-bit OS
>       armv8: fsl-layerscape: Support loading 32-bit OS with PSCI enabled
>
>  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/sec_firmware_asm.S         |  23 ++++++++++++
>  arch/arm/cpu/armv8/start.S                    |   8 +++++
>  arch/arm/cpu/armv8/transition.S               |  35 ++++++++++++++----
>  arch/arm/include/asm/arch-fsl-layerscape/mp.h |   6 ++++
>  arch/arm/include/asm/macro.h                  | 176 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----------------------
>  arch/arm/include/asm/system.h                 | 121 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
>  arch/arm/lib/bootm.c                          |  45 ++++++++++++++++++++---
>  arch/arm/mach-rmobile/lowlevel_init_gen3.S    |   9 ++++-
>  common/image-fit.c                            |  19 +++++++++-
>  12 files changed, 451 insertions(+), 68 deletions(-)
>