[PATCH RT 0/3] riscv: add PREEMPT_RT support

[Jisheng Zhang]

This series is to add PREEMPT_RT support to riscv. Compared with last
try[1], there are two major changes:

1. riscv has been converted to Generic Entry. And riscv uses
asm-generic/preeempt.h, so we need to patch asm-generic's preeempt to
enable lazy preempt support for riscv. This is what patch1 does.
However, it duplicates the preempt_lazy_count() defintion, I'm sure
there must be an elegant solution. Neverless, it doesn't impact the
riscv PREEMPT_RT support itself.

2. three preparation patches(patch1/2/3 in [1]) has been merged in
mainline.

I back-ported the lastest linux-6.3.y-rt patches to the lastest Linus tree,
then cook this series.

Link: https://lore.kernel.org/linux-riscv/20220831175920.2806-1-jszhang@kernel.org/

Jisheng Zhang (3):
  asm-generic/preempt: also check preempt_lazy_count for
    should_resched() etc.
  riscv: add lazy preempt support
  riscv: Allow to enable RT

 arch/riscv/Kconfig                   | 2 ++
 arch/riscv/include/asm/thread_info.h | 5 ++++-
 arch/riscv/kernel/asm-offsets.c      | 1 +
 include/asm-generic/preempt.h        | 8 +++++++-
 4 files changed, 14 insertions(+), 2 deletions(-)

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2.40.1