arm64 updates/fixes for 6.19-rc2

Hi Linus,

Please pull the arm64 updates below. There are two cleanups that I did not push during the merging window because of conflicts with other series going in via the tip and crypto trees. The other is a GCS fix.

Thanks.

The following changes since commit 8f0b4cce4481fb22653697cced8d0d04027cb1e8:

Linux 6.19-rc1 (2025-12-14 16:05:07 +1200)

are available in the Git repository at:

git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux tags/arm64-fixes

for you to fetch changes up to f4ea8e05f2a857d5447c25f7daf00807d38b307d:

lkdtm/bugs: Do not confuse the clang/objtool with busy wait loop (2025-12-19 15:09:09 +0000)

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Two left-over updates that could not go into -rc1 due to conflicts with other series:

- Simplify checks in arch_kfence_init_pool() since force_pte_mapping() already takes BBML2-noabort (break-before-make Level 2 with no aborts generated) into account

- Remove unneeded SVE/SME fallback preserve/store handling in the arm64 EFI. With the recent updates, the fallback path is only taken for EFI runtime calls from hardirq or NMI contexts. In practice, this only happens under panic/oops/emergency_restart() and no restoring of the user state expected. There's a corresponding lkdtm update to trigger a BUG() or panic() from hardirq context together with a fixup not to confuse clang/objtool about the control flow

GCS (guarded control stacks) fix: flush the GCS locking state on exec, otherwise the new task will not be able to enable GCS (locked as disabled).

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Ard Biesheuvel (2):
lkdtm/bugs: Add cases for BUG and PANIC occurring in hardirq context arm64/efi: Remove unneeded SVE/SME fallback preserve/store handling

Catalin Marinas (1):
lkdtm/bugs: Do not confuse the clang/objtool with busy wait loop

Kevin Brodsky (1):
arm64: mm: Simplify check in arch_kfence_init_pool()

Mark Brown (1):
arm64/gcs: Flush the GCS locking state on exec

 arch/arm64/kernel/fpsimd.c              | 130 +++++---------------------------
 arch/arm64/kernel/process.c             |   1 +
 arch/arm64/mm/mmu.c                     |  33 ++++----
 drivers/misc/lkdtm/bugs.c               |  53 +++++++++++++
 tools/testing/selftests/lkdtm/tests.txt |   2 +
 5 files changed, 92 insertions(+), 127 deletions(-)

Catalin