[PATCH 0/7] arm64: hibernate: dust off the suspend/cleanup rework

[Bradley Morgan <brads@mainlining.org>]

This comes out of the hibernate resume discussion where Will asked if
the restored kernel's hyp vectors are reinstalled before we come back
from swsusp_arch_suspend() and free the reserved pages. Rather than
answer with a one off fix, this series reworks resume to look like a
resume from idle, which makes the answer fall out on its own.

The series leans on Mark Rutland's old work for inspiration, he had the
same end goal in a branch from back then:

  https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/log/?h=arm64/suspend/cleanup

The short answer to the question: yes, but only because the rework makes
resume look like a resume from idle. We enter cpu_resume() at the highest
available EL with the MMU off, and the resumed kernel installs its own
hyp stub vectors into VBAR_EL2 through init_kernel_el() before anything
else runs, so by the time swsusp_free() releases the trans_pgd copies
nothing points at them anymore.

The series is structured so the first patch stands alone as a stable
worthy fix for the missing hvc arguments. The rest is the cleanup: the
stale init_kernel_el() comment gets corrected, MTE tag pages get freed
after save instead of leaking on failed hibernates, the fragile
_cpu_resume() calling convention gets split, and the last patch reworks
hibernate to use the regular cpu_resume() logic end to end.

Everything object compiles and passes checkpatch and sparse. I could not
boot or run a hibernate cycle on real hardware here, so that still wants
doing before anyone gets excited.

Bradley Morgan (7):
  arm64: hibernate: pass HVC_SET_VECTORS args to the resume hvc
  arm64: head: correct comment for init_kernel_el()
  arm64: hibernate: free MTE tag pages after saving
  arm64: hibernate: fix _cpu_resume() calling convention
  arm64: hibernate: use dcache_by_myline_op
  arm64: hibernate: only clean to PoC
  arm64: hibernate: use regular cpu_resume() logic

 arch/arm64/include/asm/suspend.h  |  1 -
 arch/arm64/kernel/head.S          |  6 +--
 arch/arm64/kernel/hibernate-asm.S | 87 +++++++++++++++++++------------
 arch/arm64/kernel/hibernate.c     | 66 +++++++++++------------
 arch/arm64/kernel/sleep.S         |  6 +--
 5 files changed, 88 insertions(+), 78 deletions(-)

-- 
2.47.3