[PATCH v3 0/5] Minimal build for RISCV

[Connor Davis <connojdavis@xxxxxxxxx>]

Hi all,

This series introduces a minimal build for RISCV. It is based on Bobby's
previous work from last year[0] rebased onto current Xen.

This series provides the patches necessary to get a minimal build
working. The build is "minimal" in the sense that it only supports
building TARGET=head.o. The arch/riscv/head.S is just a simple while(1).

The first 3 patches are mods to non-RISCV bits that enable building a
config with:

  !CONFIG_HAS_NS16550
  !CONFIG_HAS_PASSTHROUGH
  !CONFIG_GRANT_TABLE

respectively. The fourth patch adds the make/Kconfig boilerplate
alongside head.S and asm-riscv/config.h (head.S references ENTRY
that is defined in asm-riscv/config.h).

The last adds a docker container for doing the build. To build from the
docker container (after creating it locally), you can run the following:

  $ make XEN_TARGET_ARCH=riscv64 SUBSYSTEMS=xen -C xen TARGET=head.o

--
Changes since v2:
  - Reduced number of riscv files added to ease review

Changes since v1:
  - Dropped "xen/sched: Fix build when NR_CPUS == 1" since this was
    fixed for 4.15
  - Moved #ifdef-ary around iommu_enabled to iommu.h
  - Moved struct grant_table declaration above ifdef CONFIG_GRANT_TABLE
    instead of defining an empty struct when !CONFIG_GRANT_TABLE

Connor Davis (5):
  xen/char: Default HAS_NS16550 to y only for X86 and ARM
  xen/common: Guard iommu symbols with CONFIG_HAS_PASSTHROUGH
  xen: Fix build when !CONFIG_GRANT_TABLE
  xen: Add files needed for minimal riscv build
  automation: Add container for riscv64 builds

 automation/build/archlinux/riscv64.dockerfile |  33 ++++++
 automation/scripts/containerize               |   1 +
 config/riscv64.mk                             |   5 +
 xen/Makefile                                  |   8 +-
 xen/arch/riscv/Kconfig                        |  52 +++++++++
 xen/arch/riscv/Kconfig.debug                  |   0
 xen/arch/riscv/Makefile                       |   0
 xen/arch/riscv/Rules.mk                       |   0
 xen/arch/riscv/arch.mk                        |  16 +++
 xen/arch/riscv/asm-offsets.c                  |   0
 xen/arch/riscv/configs/riscv64_defconfig      |  12 ++
 xen/arch/riscv/head.S                         |   6 +
 xen/common/memory.c                           |  10 ++
 xen/drivers/char/Kconfig                      |   2 +-
 xen/include/asm-riscv/config.h                | 110 ++++++++++++++++++
 xen/include/xen/grant_table.h                 |   3 +-
 xen/include/xen/iommu.h                       |   8 +-
 17 files changed, 261 insertions(+), 5 deletions(-)
 create mode 100644 automation/build/archlinux/riscv64.dockerfile
 create mode 100644 config/riscv64.mk
 create mode 100644 xen/arch/riscv/Kconfig
 create mode 100644 xen/arch/riscv/Kconfig.debug
 create mode 100644 xen/arch/riscv/Makefile
 create mode 100644 xen/arch/riscv/Rules.mk
 create mode 100644 xen/arch/riscv/arch.mk
 create mode 100644 xen/arch/riscv/asm-offsets.c
 create mode 100644 xen/arch/riscv/configs/riscv64_defconfig
 create mode 100644 xen/arch/riscv/head.S
 create mode 100644 xen/include/asm-riscv/config.h

-- 
2.31.1