linux/arch/arm64/mm
Baolin Wang ae07562909 mm: change huge_ptep_clear_flush() to return the original pte
Patch series "Fix CONT-PTE/PMD size hugetlb issue when unmapping or migrating", v4.

presently, migrating a hugetlb page or unmapping a poisoned hugetlb page,
we'll use ptep_clear_flush() and set_pte_at() to nuke the page table entry
and remap it, and this is incorrect for CONT-PTE or CONT-PMD size hugetlb
page, which will cause potential data consistent issue.  This patch set
will change to use hugetlb related APIs to fix this issue.

Note: Mike pointed out the huge_ptep_get() will only return the one
specific value, and it would not take into account the dirty or young bits
of CONT-PTE/PMDs like the huge_ptep_get_and_clear() [1].  This
inconsistent issue is not introduced by this patch set, and this issue
will be addressed in another thread [2].  Meanwhile the uffd for hugetlb
case [3] pointed out by Gerald also needs another patch to address.

[1] https://lore.kernel.org/linux-mm/85bd80b4-b4fd-0d3f-a2e5-149559f2f387@oracle.com/
[2] https://lore.kernel.org/all/cover.1651998586.git.baolin.wang@linux.alibaba.com/
[3] https://lore.kernel.org/linux-mm/20220503120343.6264e126@thinkpad/


This patch (of 3):

It is incorrect to use ptep_clear_flush() to nuke a hugetlb page table
when unmapping or migrating a hugetlb page, and will change to use
huge_ptep_clear_flush() instead in the following patches.

So this is a preparation patch, which changes the huge_ptep_clear_flush()
to return the original pte to help to nuke a hugetlb page table.

[baolin.wang@linux.alibaba.com: fix build in several more architectures]
  Link: https://lkml.kernel.org/r/0009a4cd-2826-e8be-e671-f050d4f18d5d@linux.alibaba.com
[sfr@canb.auug.org.au: fixup]
  Link: https://lkml.kernel.org/r/20220511181531.7f27a5c1@canb.auug.org.au
Link: https://lkml.kernel.org/r/cover.1652270205.git.baolin.wang@linux.alibaba.com
Link: https://lkml.kernel.org/r/20f77ddab90baa249bd24504c413189b82acde69.1652270205.git.baolin.wang@linux.alibaba.com
Link: https://lkml.kernel.org/r/cover.1652147571.git.baolin.wang@linux.alibaba.com
Link: https://lkml.kernel.org/r/dcf065868cce35bceaf138613ad27f17bb7c0c19.1652147571.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Yoshinori Sato <ysato@users.osdn.me>
Cc: Rich Felker <dalias@libc.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-13 16:48:55 -07:00
..
cache.S arm64: clean up symbol aliasing 2022-02-22 16:21:34 +00:00
context.c arm64: mm: Use asid feature macro for cheanup 2021-12-10 18:24:20 +00:00
copypage.c arm64: mte: reset the page tag in page->flags 2020-12-22 12:55:07 -08:00
dma-mapping.c iommu/dma: Pass address limit rather than size to iommu_setup_dma_ops() 2021-06-25 15:02:43 +02:00
extable.c arm64: extable: fix load_unaligned_zeropad() reg indices 2022-01-26 18:58:12 +00:00
fault.c Merge branch 'signal-for-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2022-01-17 05:49:30 +02:00
flush.c mm: hugetlb_vmemmap: cleanup CONFIG_HUGETLB_PAGE_FREE_VMEMMAP* 2022-04-28 23:16:15 -07:00
hugetlbpage.c mm: change huge_ptep_clear_flush() to return the original pte 2022-05-13 16:48:55 -07:00
init.c arm64: fix typos in comments 2022-04-04 10:32:50 +01:00
ioremap.c arm64: decouple check whether pfn is in linear map from pfn_valid() 2021-06-30 20:47:29 -07:00
kasan_init.c kasan: add kasan mode messages when kasan init 2021-11-11 09:34:35 -08:00
Makefile arm64: trans_pgd: hibernate: Add trans_pgd_copy_el2_vectors 2021-10-01 13:30:59 +01:00
mmap.c arm64/mm: enable ARCH_HAS_VM_GET_PAGE_PROT 2022-04-28 23:16:13 -07:00
mmu.c Folio changes for 5.18 2022-03-22 17:03:12 -07:00
mteswap.c arm64: mte: Define the number of bytes for storing the tags in a page 2022-02-15 22:53:29 +00:00
pageattr.c kasan, arm64: don't tag executable vmalloc allocations 2022-03-24 19:06:48 -07:00
pgd.c mm: consolidate pgtable_cache_init() and pgd_cache_init() 2019-09-24 15:54:09 -07:00
physaddr.c arm64: Do not pass tagged addresses to __is_lm_address() 2021-02-02 17:44:47 +00:00
proc.S arm64/mm: Consolidate TCR_EL1 fields 2022-02-15 15:34:22 +00:00
ptdump_debugfs.c arm64: Add __init section marker to some functions 2021-04-08 17:45:10 +01:00
ptdump.c arm64/bpf: Remove 128MB limit for BPF JIT programs 2021-11-08 22:16:26 +01:00
trans_pgd-asm.S arm64: kexec: configure EL2 vectors for kexec 2021-10-01 13:31:00 +01:00
trans_pgd.c arm64: trans_pgd: remove trans_pgd_map_page() 2021-10-01 13:31:01 +01:00