riscv: Add Zalasr ISA extension support

This patch adds support for the Zalasr ISA extension, which supplies the
real load acquire/store release instructions.

The specification can be found here:
https://github.com/riscv/riscv-zalasr/blob/main/chapter2....

This patch seires has been tested with ltp on Qemu with Brensan's zalasr
support patch[1].

Some false positive spacing error happens during patch checking. Thus I
CCed maintainers of checkpatch.pl as well.

[1] https://lore.kernel.org/all/CAGPSXwJEdtqW=nx71oufZp64nK6t...

v4:
 - Apply acquire/release semantics to arch_atomic operations. Thanks
 to Andrea.

v3:
 - Apply acquire/release semantics to arch_xchg/arch_cmpxchg operations
 so as to ensure FENCE.TSO ordering between operations which precede the
 UNLOCK+LOCK sequence and operations which follow the sequence. Thanks
 to Andrea.
 - Support hwprobe of Zalasr.
 - Allow Zalasr extensions for Guest/VM.

v2:
 - Adjust the order of Zalasr and Zalrsc in dt-bindings. Thanks to
 Conor.

Xu Lu (10):
  riscv: Add ISA extension parsing for Zalasr
  dt-bindings: riscv: Add Zalasr ISA extension description
  riscv: hwprobe: Export Zalasr extension
  riscv: Introduce Zalasr instructions
  riscv: Apply Zalasr to smp_load_acquire/smp_store_release
  riscv: Apply acquire/release semantics to arch_xchg/arch_cmpxchg
    operations
  riscv: Apply acquire/release semantics to arch_atomic operations
  riscv: Remove arch specific __atomic_acquire/release_fence
  RISC-V: KVM: Allow Zalasr extensions for Guest/VM
  RISC-V: KVM: selftests: Add Zalasr extensions to get-reg-list test

 Documentation/arch/riscv/hwprobe.rst          |   5 +-
 .../devicetree/bindings/riscv/extensions.yaml |   5 +
 arch/riscv/include/asm/atomic.h               |  70 ++++++++-
 arch/riscv/include/asm/barrier.h              |  91 +++++++++--
 arch/riscv/include/asm/cmpxchg.h              | 144 +++++++++---------
 arch/riscv/include/asm/fence.h                |   4 -
 arch/riscv/include/asm/hwcap.h                |   1 +
 arch/riscv/include/asm/insn-def.h             |  79 ++++++++++
 arch/riscv/include/uapi/asm/hwprobe.h         |   1 +
 arch/riscv/include/uapi/asm/kvm.h             |   1 +
 arch/riscv/kernel/cpufeature.c                |   1 +
 arch/riscv/kernel/sys_hwprobe.c               |   1 +
 arch/riscv/kvm/vcpu_onereg.c                  |   2 +
 .../selftests/kvm/riscv/get-reg-list.c        |   4 +
 14 files changed, 314 insertions(+), 95 deletions(-)

-- 
2.20.1