[v3,0/3] Early serial on Power

Message

Shawn Anastasio July 6, 2023, 7:04 p.m. UTC

Hello all,

This series adds support for early serial printing on Power, as well as
a simple CI smoke test modeled after the riscv one.

The first patch is responsible for setting up a basic C environment with
an initial stack while the second sets up an Open Firmware serial console
and primitive early_printk infrastructure.

This will currently only run on QEMU pseries VMs, since the firmware
interface on bare metal differs significantly. Support for bare metal
will be added in a future series.

Thanks,
Shawn

--
Changes in v3:
  - Set up r2 TOC pointer in start
  - Change indirect call to start_xen to a direct one
  - Use 32-bit constant loads for stack pointer, etc. in start
      - Our load address is < 4GB so this works fine
      - In a future series we'll get -fPIC working and change all of
        these immediate address loads to TOC-relative ones.
  - Move .bss initialization to patch 2
  - Move cpu0_boot_stack declaration to setup.c
  - Bump stack size down to one page (64k), previous was way overkill.
  - Remove unnecessary STACK_FRAME_OVERHEAD component from of-call.S
    stack frame size calculation
  - Add assertion that `struct cpu_user_regs` is stack-aligned
  - Move magic `or 31,31,31` to appropriately-named macro
  - Fix formatting of loop in setup.c
  - Add newline in arch/ppc/Makefile to preserve alphabetical ordering
    per group
  - Rebase on staging, including the final version of
    'xen/types: Rework stdint vs __{u,s}$N types'

Changes in v2:
  - Split main patch into two - one for basic C environment setup and
    one for serial
  - Mark OpenFirmware functions and early_printk functions as __init and
    change boot-of.o to boot-of.init.o in Makefile
  - Change <xen/lib.h> include to <xen/stdarg.h> and drop skeleton
    headers that are no longer necessary for build as a result
  - Add loop to clear .bss before jumping to C environment that was
    accidentally excluded from the first series
  - Move common asm macros from processor.h to asm-defns.h
  - Change note in head.S about preserved registers to a multi-line
    comment so it's more noticeable
  - Drop reg-defs.h and use '%'-prefixed register names in assembly
      - This is necessary since -mregnames, which allows standard
        non-prefixed register names without manual macro definitions,
        is not supported by LLVM's assembler.
  - Drop inline asm swab routines in favor of __builtin_bswap family
  - Fix up types.h in accordance with (as of now, unmerged)
    'xen/types: Rework stdint vs __{u,s}$N types'
  - Remove unnecessary braces for single-line statements
  - Remove unnecessary license text when SPDX header is present
  - Fix alphabetical ordering of object declarations in Makefile
  - Drop 'extern' from enter_of prototype, ensure prototypes have
    argument names

Shawn Anastasio (3):
  xen/ppc: Set up a basic C environment
  xen/ppc: Implement early serial printk on pseries
  automation: Add smoke test for ppc64le

 automation/gitlab-ci/test.yaml           |  20 ++++
 automation/scripts/qemu-smoke-ppc64le.sh |  27 +++++
 xen/arch/ppc/Kconfig.debug               |   5 +
 xen/arch/ppc/Makefile                    |   4 +
 xen/arch/ppc/boot-of.c                   | 100 ++++++++++++++++
 xen/arch/ppc/configs/ppc64_defconfig     |   1 +
 xen/arch/ppc/early_printk.c              |  28 +++++
 xen/arch/ppc/include/asm/asm-defns.h     |  57 ++++++++++
 xen/arch/ppc/include/asm/boot.h          |  23 ++++
 xen/arch/ppc/include/asm/byteorder.h     |  12 ++
 xen/arch/ppc/include/asm/config.h        |   5 +-
 xen/arch/ppc/include/asm/early_printk.h  |  15 +++
 xen/arch/ppc/include/asm/msr.h           |  51 +++++++++
 xen/arch/ppc/include/asm/processor.h     | 139 +++++++++++++++++++++++
 xen/arch/ppc/include/asm/types.h         |  21 ++++
 xen/arch/ppc/ppc64/Makefile              |   1 +
 xen/arch/ppc/ppc64/asm-offsets.c         |  59 ++++++++++
 xen/arch/ppc/ppc64/head.S                |  49 ++++----
 xen/arch/ppc/ppc64/of-call.S             |  83 ++++++++++++++
 xen/arch/ppc/setup.c                     |  32 ++++++
 20 files changed, 711 insertions(+), 21 deletions(-)
 create mode 100755 automation/scripts/qemu-smoke-ppc64le.sh
 create mode 100644 xen/arch/ppc/boot-of.c
 create mode 100644 xen/arch/ppc/early_printk.c
 create mode 100644 xen/arch/ppc/include/asm/asm-defns.h
 create mode 100644 xen/arch/ppc/include/asm/boot.h
 create mode 100644 xen/arch/ppc/include/asm/byteorder.h
 create mode 100644 xen/arch/ppc/include/asm/early_printk.h
 create mode 100644 xen/arch/ppc/include/asm/msr.h
 create mode 100644 xen/arch/ppc/include/asm/processor.h
 create mode 100644 xen/arch/ppc/include/asm/types.h
 create mode 100644 xen/arch/ppc/ppc64/of-call.S
 create mode 100644 xen/arch/ppc/setup.c

--
2.30.2