[PATCH v2 0/2] riscv: Enable percpu page first chunk allocator

[Alexandre Ghiti <alexghiti@rivosinc.com>]

While working with pcpu variables, I noticed that riscv did not support
first chunk allocation in the vmalloc area which may be needed as a fallback
in case of a sparse NUMA configuration.

patch 1 starts by introducing a new function flush_cache_vmap_early() which
is needed since a new vmalloc mapping is established and directly accessed:
on riscv, this would likely fail in case of a reordered access or if the
uarch caches invalid entries in TLB.
Note that most architectures do not include asm-generic/cacheflush.h so to
avoid build failures, this patch implements the new function on each of
those architectures. For all architectures except riscv, this new function
is implemented as a no-op to keep the existing behaviour but it likely
needs another implementation.

patch 2 simply enables the page percpu first chunk allocator in riscv.

Changes in v2:
- Rebase on top of 6.7
- Define flush_cache_vmap_early() for all architectures that do
  not include <asm-generic/cacheflush.h> to avoid build failures

Alexandre Ghiti (2):
  mm: Introduce flush_cache_vmap_early()
  riscv: Enable pcpu page first chunk allocator

 arch/arc/include/asm/cacheflush.h      | 1 +
 arch/arm/include/asm/cacheflush.h      | 2 ++
 arch/csky/abiv1/inc/abi/cacheflush.h   | 1 +
 arch/csky/abiv2/inc/abi/cacheflush.h   | 1 +
 arch/m68k/include/asm/cacheflush_mm.h  | 1 +
 arch/mips/include/asm/cacheflush.h     | 2 ++
 arch/nios2/include/asm/cacheflush.h    | 1 +
 arch/parisc/include/asm/cacheflush.h   | 1 +
 arch/riscv/Kconfig                     | 2 ++
 arch/riscv/include/asm/cacheflush.h    | 3 ++-
 arch/riscv/include/asm/tlbflush.h      | 1 +
 arch/riscv/mm/kasan_init.c             | 8 ++++++++
 arch/riscv/mm/tlbflush.c               | 5 +++++
 arch/sh/include/asm/cacheflush.h       | 1 +
 arch/sparc/include/asm/cacheflush_32.h | 1 +
 arch/sparc/include/asm/cacheflush_64.h | 1 +
 arch/xtensa/include/asm/cacheflush.h   | 6 ++++--
 include/asm-generic/cacheflush.h       | 6 ++++++
 mm/percpu.c                            | 8 +-------
 19 files changed, 42 insertions(+), 10 deletions(-)

-- 
2.39.2