[v2,00/10] Zacas/Zabha support and qspinlocks

Message

Alexandre Ghiti June 26, 2024, 1:03 p.m. UTC

This implements [cmp]xchgXX() macros using Zacas and Zabha extensions
and finally uses those newly introduced macros to add support for
qspinlocks: note that this implementation of qspinlocks satisfies the
forward progress guarantee.

Thanks to Guo and Leonardo for their work!

Changes in v2:
- Add patch for Zabha dtbinding (Conor)
- Fix cmpxchg128() build warnings missed in v1
- Make arch_cmpxchg128() fully ordered
- Improve Kconfig help texts for both extensions (Conor)
- Fix Makefile dependencies by requiring TOOLCHAIN_HAS_XXX (Nathan)
- Fix compilation errors when the toolchain does not support the
  extensions (Nathan)
- Fix C23 warnings about label at the end of coumpound statements (Nathan)
- Fix Zabha and !Zacas configurations (Andrea)
- Add COMBO spinlocks (Guo)
- Improve amocas fully ordered operations by using .aqrl semantics and
  removing the fence rw, rw (Andrea)
- Rebase on top "riscv: Fix fully ordered LR/SC xchg[8|16]() implementations"
- Add ARCH_WEAK_RELEASE_ACQUIRE (Andrea)
- Remove the extension version in march for LLVM since it is only required
  for experimental extensions (Nathan)
- Fix cmpxchg128() implementation by adding both registers of a pair
  in the list of input/output operands

Alexandre Ghiti (8):
  riscv: Implement cmpxchg32/64() using Zacas
  dt-bindings: riscv: Add Zabha ISA extension description
  riscv: Implement cmpxchg8/16() using Zabha
  riscv: Improve amocas.X use in cmpxchg()
  riscv: Implement arch_cmpxchg128() using Zacas
  riscv: Implement xchg8/16() using Zabha
  riscv: Improve amoswap.X use in xchg()
  riscv: Add qspinlock support based on Zabha extension

Guo Ren (2):
  asm-generic: ticket-lock: Reuse arch_spinlock_t of qspinlock
  asm-generic: ticket-lock: Add separate ticket-lock.h

 .../devicetree/bindings/riscv/extensions.yaml |   6 +
 .../locking/queued-spinlocks/arch-support.txt |   2 +-
 arch/riscv/Kconfig                            |  45 +++++
 arch/riscv/Makefile                           |   6 +
 arch/riscv/include/asm/Kbuild                 |   4 +-
 arch/riscv/include/asm/cmpxchg.h              | 188 ++++++++++++++----
 arch/riscv/include/asm/hwcap.h                |   1 +
 arch/riscv/include/asm/spinlock.h             |  39 ++++
 arch/riscv/kernel/cpufeature.c                |   1 +
 arch/riscv/kernel/setup.c                     |  21 ++
 include/asm-generic/qspinlock.h               |   2 +
 include/asm-generic/spinlock.h                |  87 +-------
 include/asm-generic/spinlock_types.h          |  12 +-
 include/asm-generic/ticket_spinlock.h         | 105 ++++++++++
 14 files changed, 385 insertions(+), 134 deletions(-)
 create mode 100644 arch/riscv/include/asm/spinlock.h
 create mode 100644 include/asm-generic/ticket_spinlock.h