Merge tag 'alpha-for-v7.4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/lindholm/alpha

Pull alpha updates from Magnus Lindholm:
"This completes Alpha's conversion to GENERIC_ENTRY and enabl

Merge tag 'alpha-for-v7.4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/lindholm/alpha

Pull alpha updates from Magnus Lindholm:
"This completes Alpha's conversion to GENERIC_ENTRY and enables a range
of kernel features through Kconfig updates, including UBSAN, gcov,
kmemleak, page-table checking, fast GUP and sparse IRQs.

It includes TLB and MMU context fixes prompted by glibc test-suite
failures, HugeTLB support for 64KB, 512KB and 4MB pages, and fixes for
poisoned-page faults and page-table checking.

Machine-check handling is improved on Tsunami platforms, with bounded
EV6 logout decoding, Clipper environmental event reporting and safer
firmware console-log scanning.

Other changes add self-extracting compressed kernels with support for
all kernel compression formats, Alpha-specific XZ tuning, perf
register and user-stack sampling, and Alpha support in the seccomp
selftests. The series also fixes user stack-pointer reporting and IRQ
entry ordering, adds 128-bit shift helpers, cleans up linker sections,
and updates Kconfig help"

* tag 'alpha-for-v7.4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/lindholm/alpha: (57 commits)
alpha: add bounded Clipper console-log scanning
alpha: decode Clipper environmental events
alpha: decode and acknowledge Tsunami system machine checks
alpha: bound EV6 logout decoding by the processor area
alpha: describe the Tsunami system machine check frame
alpha: move Tsunami machine check handling to err_tsunami.c
alpha: fill in pc for software event samples
alpha: add HAVE_PERF_REGS and HAVE_PERF_USER_STACK_DUMP support
alpha: use user_stack_pointer() in KSTK_ESP() and dump_elf_thread()
alpha: stop storing the user stack pointer in pt_regs
alpha: fix stale user_stack_pointer()
selftests/seccomp: add Alpha support to seccomp_bpf
alpha: do not skip TLB shootdown IPIs for kthread-borrowed mms
alpha: do not clear remote MMU contexts in migrate_flush_tlb_page()
alpha: invalidate the local context in flush_icache_user_page()
alpha: invalidate the local context in flush_tlb_mm()
alpha: fix the local TLB invalidate in the UP flush_tlb_page()
alpha: fix the local TLB invalidate in flush_tlb_page()
alpha: invalidate the local context in flush_tlb_page()
alpha: only use a targeted tbi() when the target mm is really current
...

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alpha: implement hugetlb support

Alpha has no leaf entry above the last page table level, so the only
huge pages it can offer are granularity hint blocks: 64KB, 512KB and 4MB
with 8KB pages. Registe

alpha: implement hugetlb support

Alpha has no leaf entry above the last page table level, so the only
huge pages it can offer are granularity hint blocks: 64KB, 512KB and 4MB
with 8KB pages. Register all three as hstates, with 4MB as the default.
There is no PMD sized huge page, hence no transparent huge pages, no PMD
page table sharing and no gigantic pages.

As with arm64's contiguous PTEs, each PTE of a block keeps the frame
number of its own page, so a block is written with set_ptes(). Each
hstate's buddy order is its hint order, so a hugetlb folio is always
naturally aligned physically, as the hint requires, including after a
demote.

All PTEs of a block must agree in bits <15:0> (note 2 of Table 22-3 of
the Alpha Architecture Reference Manual), and both __ACCESS_BITS and
__DIRTY_BITS reach into that range, so every update rewrites the whole
block and huge_ptep_get() merges the young and dirty state back
together. Rewriting a valid block in place would leave its PTEs
disagreeing part way through, so changes to a valid block go through
break before make, following the procedure in section 11.6.1.

The hint is advisory, so this is safe on implementations that ignore it,
and gup_fast needs no changes since it walks the individual PTEs.

Enabling CONFIG_HUGETLB_PAGE derives pageblock_order from
HUGETLB_PAGE_ORDER, which lowers it from 10 to 9 and so halves the
anti-fragmentation and compaction granularity from 8MB to 4MB.

Hugepage migration is left disabled, since it has not been tested.

Co-developed-by: Magnus Lindholm <linmag7@gmail.com>
Signed-off-by: Magnus Lindholm <linmag7@gmail.com>
Signed-off-by: Matt Turner <mattst88@gmail.com>
Tested-by: Magnus Lindholm <linmag7@gmail.com>
Reviewed-by: Magnus Lindholm <linmag7@gmail.com>
Link: https://lore.kernel.org/r/20261007-alpha-hugepages-v2-6-8e108af2d961@gmail.com
Signed-off-by: Magnus Lindholm <linmag7@gmail.com>

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