Re: [PATCH for-next 5/6] xen: Add files needed for minimal riscv build

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 25/02/2021 15:24, Connor Davis wrote:
> Add the minimum code required to get xen to build with
> XEN_TARGET_ARCH=riscv64. It is minimal in the sense that every file and
> function added is required for a successful build, given the .config
> generated from riscv64_defconfig. The function implementations are just
> stubs; actual implmentations will need to be added later.
>
> Signed-off-by: Connor Davis <connojdavis@gmail.com>
> ---
>  config/riscv64.mk                        |   7 +
>  xen/Makefile                             |   8 +-
>  xen/arch/riscv/Kconfig                   |  54 ++++
>  xen/arch/riscv/Kconfig.debug             |   0
>  xen/arch/riscv/Makefile                  |  57 ++++
>  xen/arch/riscv/README.source             |  19 ++
>  xen/arch/riscv/Rules.mk                  |  13 +
>  xen/arch/riscv/arch.mk                   |   7 +
>  xen/arch/riscv/configs/riscv64_defconfig |  12 +
>  xen/arch/riscv/delay.c                   |  16 +
>  xen/arch/riscv/domain.c                  | 144 +++++++++
>  xen/arch/riscv/domctl.c                  |  36 +++
>  xen/arch/riscv/guestcopy.c               |  57 ++++
>  xen/arch/riscv/head.S                    |   6 +
>  xen/arch/riscv/irq.c                     |  78 +++++
>  xen/arch/riscv/lib/Makefile              |   1 +
>  xen/arch/riscv/lib/find_next_bit.c       | 284 +++++++++++++++++
>  xen/arch/riscv/mm.c                      |  93 ++++++
>  xen/arch/riscv/p2m.c                     | 150 +++++++++
>  xen/arch/riscv/percpu.c                  |  17 +
>  xen/arch/riscv/platforms/Kconfig         |  31 ++
>  xen/arch/riscv/riscv64/asm-offsets.c     |  31 ++
>  xen/arch/riscv/setup.c                   |  27 ++
>  xen/arch/riscv/shutdown.c                |  28 ++
>  xen/arch/riscv/smp.c                     |  35 +++
>  xen/arch/riscv/smpboot.c                 |  34 ++
>  xen/arch/riscv/sysctl.c                  |  33 ++
>  xen/arch/riscv/time.c                    |  35 +++
>  xen/arch/riscv/traps.c                   |  35 +++
>  xen/arch/riscv/vm_event.c                |  39 +++
>  xen/arch/riscv/xen.lds.S                 | 113 +++++++
>  xen/drivers/char/serial.c                |   1 +
>  xen/include/asm-riscv/altp2m.h           |  39 +++
>  xen/include/asm-riscv/asm.h              |  77 +++++
>  xen/include/asm-riscv/asm_defns.h        |  24 ++
>  xen/include/asm-riscv/atomic.h           | 204 ++++++++++++
>  xen/include/asm-riscv/bitops.h           | 331 ++++++++++++++++++++
>  xen/include/asm-riscv/bug.h              |  54 ++++
>  xen/include/asm-riscv/byteorder.h        |  16 +
>  xen/include/asm-riscv/cache.h            |  24 ++
>  xen/include/asm-riscv/cmpxchg.h          | 382 +++++++++++++++++++++++
>  xen/include/asm-riscv/compiler_types.h   |  32 ++
>  xen/include/asm-riscv/config.h           | 110 +++++++
>  xen/include/asm-riscv/cpufeature.h       |  17 +
>  xen/include/asm-riscv/csr.h              | 219 +++++++++++++
>  xen/include/asm-riscv/current.h          |  47 +++
>  xen/include/asm-riscv/debugger.h         |  15 +
>  xen/include/asm-riscv/delay.h            |  15 +
>  xen/include/asm-riscv/desc.h             |  12 +
>  xen/include/asm-riscv/device.h           |  15 +
>  xen/include/asm-riscv/div64.h            |  23 ++
>  xen/include/asm-riscv/domain.h           |  50 +++
>  xen/include/asm-riscv/event.h            |  42 +++
>  xen/include/asm-riscv/fence.h            |  12 +
>  xen/include/asm-riscv/flushtlb.h         |  34 ++
>  xen/include/asm-riscv/grant_table.h      |  12 +
>  xen/include/asm-riscv/guest_access.h     |  41 +++
>  xen/include/asm-riscv/guest_atomics.h    |  60 ++++
>  xen/include/asm-riscv/hardirq.h          |  27 ++
>  xen/include/asm-riscv/hypercall.h        |  12 +
>  xen/include/asm-riscv/init.h             |  42 +++
>  xen/include/asm-riscv/io.h               | 283 +++++++++++++++++
>  xen/include/asm-riscv/iocap.h            |  13 +
>  xen/include/asm-riscv/iommu.h            |  46 +++
>  xen/include/asm-riscv/irq.h              |  58 ++++
>  xen/include/asm-riscv/mem_access.h       |   4 +
>  xen/include/asm-riscv/mm.h               | 246 +++++++++++++++
>  xen/include/asm-riscv/monitor.h          |  65 ++++
>  xen/include/asm-riscv/nospec.h           |  25 ++
>  xen/include/asm-riscv/numa.h             |  41 +++
>  xen/include/asm-riscv/p2m.h              | 218 +++++++++++++
>  xen/include/asm-riscv/page-bits.h        |  11 +
>  xen/include/asm-riscv/page.h             |  73 +++++
>  xen/include/asm-riscv/paging.h           |  15 +
>  xen/include/asm-riscv/pci.h              |  31 ++
>  xen/include/asm-riscv/percpu.h           |  33 ++
>  xen/include/asm-riscv/processor.h        |  59 ++++
>  xen/include/asm-riscv/random.h           |   9 +
>  xen/include/asm-riscv/regs.h             |  23 ++
>  xen/include/asm-riscv/setup.h            |  14 +
>  xen/include/asm-riscv/smp.h              |  46 +++
>  xen/include/asm-riscv/softirq.h          |  16 +
>  xen/include/asm-riscv/spinlock.h         |  12 +
>  xen/include/asm-riscv/string.h           |  28 ++
>  xen/include/asm-riscv/sysregs.h          |  16 +
>  xen/include/asm-riscv/system.h           |  99 ++++++
>  xen/include/asm-riscv/time.h             |  31 ++
>  xen/include/asm-riscv/trace.h            |  12 +
>  xen/include/asm-riscv/types.h            |  60 ++++
>  xen/include/asm-riscv/vm_event.h         |  55 ++++
>  xen/include/asm-riscv/xenoprof.h         |  12 +
>  xen/include/public/arch-riscv.h          | 183 +++++++++++
>  xen/include/public/arch-riscv/hvm/save.h |  39 +++
>  xen/include/public/hvm/save.h            |   2 +
>  xen/include/public/pmu.h                 |   2 +
>  xen/include/public/xen.h                 |   2 +
>  xen/include/xen/domain.h                 |   1 +

Well - this is orders of magnitude more complicated than it ought to
be.  An empty head.S doesn't (well - shouldn't) need the overwhelming
majority of this.

Do you know how all of this is being pulled in?  Is it from attempting
to compile common/ by any chance?

Now is also an excellent opportunity to nuke the x86isms which have
escaped into common code (debugger and xenoprof in particular), and
rethink some of our common/arch split.

When it comes to header files specifically, I want to start using
xen/arch/$ARCH/include/asm/ and retrofit this to x86 and ARM.  It has
two important properties - first, that you don't need to symlink the
tree to make compilation work, and second that patches touching multiple
architectures have hunks ordered in a more logical way.

~Andrew