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linux-next/arch/arm64/mm
Will Deacon 20a004e7b0 arm64: mm: Use READ_ONCE/WRITE_ONCE when accessing page tables
In many cases, page tables can be accessed concurrently by either another
CPU (due to things like fast gup) or by the hardware page table walker
itself, which may set access/dirty bits. In such cases, it is important
to use READ_ONCE/WRITE_ONCE when accessing page table entries so that
entries cannot be torn, merged or subject to apparent loss of coherence
due to compiler transformations.

Whilst there are some scenarios where this cannot happen (e.g. pinned
kernel mappings for the linear region), the overhead of using READ_ONCE
/WRITE_ONCE everywhere is minimal and makes the code an awful lot easier
to reason about. This patch consistently uses these macros in the arch
code, as well as explicitly namespacing pointers to page table entries
from the entries themselves by using adopting a 'p' suffix for the former
(as is sometimes used elsewhere in the kernel source).

Tested-by: Yury Norov <ynorov@caviumnetworks.com>
Tested-by: Richard Ruigrok <rruigrok@codeaurora.org>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-02-16 18:13:57 +00:00
..
cache.S arm64: mm: Add additional parameter to uaccess_ttbr0_disable 2018-01-17 13:57:49 +01:00
context.c arm64: Move BP hardening to check_and_switch_context 2018-01-23 15:40:29 +00:00
copypage.c arm64: Defer dcache flush in __cpu_copy_user_page 2015-12-17 11:07:13 +00:00
dma-mapping.c arm64: use swiotlb_alloc and swiotlb_free 2018-01-15 09:36:02 +01:00
dump.c arm64: mm: Use READ_ONCE/WRITE_ONCE when accessing page tables 2018-02-16 18:13:57 +00:00
extable.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fault.c arm64: mm: Use READ_ONCE/WRITE_ONCE when accessing page tables 2018-02-16 18:13:57 +00:00
flush.c arm64: fix pmem interface definition 2017-08-10 18:13:59 +01:00
hugetlbpage.c arm64: mm: Use READ_ONCE/WRITE_ONCE when accessing page tables 2018-02-16 18:13:57 +00:00
init.c dma mapping changes for Linux 4.16: 2018-01-31 11:32:27 -08:00
ioremap.c arm64: use is_vmalloc_addr 2017-02-09 13:47:56 +00:00
kasan_init.c arm64: mm: Use READ_ONCE/WRITE_ONCE when accessing page tables 2018-02-16 18:13:57 +00:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mmap.c arm64/mmap: properly account for stack randomization in mmap_base 2017-07-12 16:26:03 -07:00
mmu.c arm64: mm: Use READ_ONCE/WRITE_ONCE when accessing page tables 2018-02-16 18:13:57 +00:00
numa.c arm64/numa: Drop duplicate message 2017-07-20 17:03:53 +01:00
pageattr.c arm64: mm: Use READ_ONCE/WRITE_ONCE when accessing page tables 2018-02-16 18:13:57 +00:00
pgd.c arm64: handle 52-bit addresses in TTBR 2017-12-22 17:35:21 +00:00
physaddr.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
proc.S arm64: proc: Set PTE_NG for table entries to avoid traversing them twice 2018-02-14 18:58:20 +00:00
ptdump_debugfs.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00