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

Alexandre Ghiti
2024-06-26T13:03:53Z

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

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2.39.2