[PATCH v4 0/3] riscv: improve percpu helpers and PIO mapping

[Yunhui Cui]

This series makes three small RISC-V cleanups and fixes around percpu access
and PIO helper handling.

This work is motivated in part by build reports from lkp and by follow-up
review/discussion around the percpu access rework:

https://lore.kernel.org/all/202512202218.FI6bB5kV-lkp@intel.com/
https://lore.kernel.org/all/202512210052.w0bpUAAO-lkp@intel.com/

1. Avoid forming invalid PIO address expressions when I/O port support is not
enabled, while keeping the generic pci_iounmap() behavior intact.

2. Introduce arch/riscv/include/asm/percpu.h with RISC-V-specific percpu
helpers, including the fix for the 8/16-bit add_return LR/SC fallback.

3. Cache the percpu offset in thread_info so percpu accesses can use it
directly across the relevant RISC-V paths.

Yunhui Cui (3):
  riscv: io: avoid null-pointer arithmetic in PIO helpers
  riscv: introduce percpu.h into include/asm
  riscv: store percpu offset into thread_info

 arch/riscv/include/asm/asm.h         |   6 +-
 arch/riscv/include/asm/io.h          |  26 ++-
 arch/riscv/include/asm/percpu.h      | 284 +++++++++++++++++++++++++++
 arch/riscv/include/asm/switch_to.h   |   8 +
 arch/riscv/include/asm/thread_info.h |   3 +-
 arch/riscv/kernel/asm-offsets.c      |   1 +
 arch/riscv/kernel/smpboot.c          |   7 +
 arch/riscv/net/bpf_jit_comp64.c      |   9 +-
 include/asm-generic/io.h             |   4 +
 9 files changed, 326 insertions(+), 22 deletions(-)
 create mode 100644 arch/riscv/include/asm/percpu.h

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2.39.5