[PATCH v3 0/4] sparc64: D-cache alias flushing fixes

[Imre Kaloz]

These fix D-cache alias flushing on sparc64 CPUs with a virtually
indexed L1 D-cache (Spitfire and Cheetah).

1/4 makes xcall_deliver() bail out before it touches the trap block
when there is no other CPU to call, so an early cross call, before
init_IRQ() sets up the mondo blocks, can't end up writing to physical
address 0.

2/4 flushes only the page a PTE maps instead of its whole folio, which
removes about a million redundant page flushes from a colour-changing
mremap() of a large folio (7.3 s on a Sun Fire V240).

3/4 implements flush_cache_vmap() and flush_cache_vunmap(), which have
been no-ops. Stale vmalloc lines corrupt BPF programs and module data
on UltraSPARC III.

4/4 passes the number of PTEs to move_pte(), as Andreas suggested. It
touches mm/mremap.c and include/linux/pgtable.h, so it needs an ack
from the mm folks.

1-3 don't depend on 4 and can go in on their own. 2 and 3 are for
stable (3 needs 2), 1 and 4 aren't. The series is on top of the sparc
for-next branch.

Changes in v3:
- new 1/4 and 4/4, following Andreas' review
- 2/4: reworded the message and the move_pte() comment, marked the
  UP #endif
- 3/4: reworded the message, dropped the Suggested-by (I have no
  email address for nsafran1217, the Link credits them), noted the
  stable dependency on 2/4
- picked up Stian's and Adrian's Tested-by tags

v2: https://lore.kernel.org/r/20260928132102.1707-1-kaloz@xxxxxxxxxx

Imre Kaloz (4):
  sparc64: skip the trap block in xcall_deliver() when there is no
    target
  sparc64: flush only the aliased page, not its whole folio
  sparc64: flush vmalloc ranges from the D-cache on map and unmap
  mm: pass the number of PTEs to move_pte()

 arch/sparc/include/asm/cacheflush_64.h |  9 ++--
 arch/sparc/include/asm/pgtable_64.h    | 14 ++++--
 arch/sparc/kernel/smp_64.c             | 51 +++++++++++++++-----
 arch/sparc/mm/init_64.c                | 65 ++++++++++++++++++++++++++
 arch/sparc/mm/tlb.c                    |  2 +-
 arch/sparc/mm/ultra.S                  | 25 ++++++++++
 include/linux/pgtable.h                |  2 +-
 mm/mremap.c                            |  2 +-
 8 files changed, 148 insertions(+), 22 deletions(-)


base-commit: 2bc58762a3d74e42de129d717ae3ba10ecf0ab96
-- 
2.47.3