arm64: implement the new page table range API

Add set_ptes(), update_mmu_cache_range() and flush_dcache_folio(). Change
the PG_dcache_clean flag from being per-page to per-folio.

Link: https://lkml.kernel.org/r/20230802151406.3735276-11-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

arm64: flush: include linux/libnvdimm.h

The two cache management functions are declared in libnvdimm.h
but provided by architecture specific code. Without including
the header, this causes a W=1 warning:

arch/arm64/mm/flush.c:96:6: error: no previous prototype for 'arch_wb_cache_pmem' [-Werror=missing-prototypes]
arch/arm64/mm/flush.c:104:6: error: no previous prototype for 'arch_invalidate_pmem' [-Werror=missing-prototypes]

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20230516160642.523862-12-arnd@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

mm: hugetlb_vmemmap: delete hugetlb_optimize_vmemmap_enabled()

Patch series "Simplify hugetlb vmemmap and improve its readability", v2.

This series aims to simplify hugetlb vmemmap and improve its readability.


This patch (of 8):

The name hugetlb_optimize_vmemmap_enabled() a bit confusing as it tests
two conditions (enabled and pages in use). Instead of coming up to an
appropriate name, we could just delete it. There is already a discussion
about deleting it in thread [1].

There is only one user of hugetlb_optimize_vmemmap_enabled() outside of
hugetlb_vmemmap, that is flush_dcache_page() in arch/arm64/mm/flush.c.
However, it does not need to call hugetlb_optimize_vmemmap_enabled() in
flush_dcache_page() since HugeTLB pages are always fully mapped and only
head page will be set PG_dcache_clean meaning only head page's flag may
need to be cleared (see commit cf5a501d985b). So it is easy to remove
hugetlb_optimize_vmemmap_enabled().

Link: https://lore.kernel.org/all/c77c61c8-8a5a-87e8-db89-d04d8aaab4cc@oracle.com/ [1]
Link: https://lkml.kernel.org/r/20220628092235.91270-2-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: hugetlb_vmemmap: cleanup CONFIG_HUGETLB_PAGE_FREE_VMEMMAP*

The word of "free" is not expressive enough to express the feature of
optimizing vmemmap pages associated with each HugeTLB, rename this keywork
to "optimize". In this patch , cheanup configs to make code more
expressive.

Link: https://lkml.kernel.org/r/20220404074652.68024-4-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: hugetlb_vmemmap: cleanup hugetlb_free_vmemmap_enabled*

The word of "free" is not expressive enough to express the feature of
optimizing vmemmap pages associated with each HugeTLB, rename this keywork
to "optimize". In this patch , cheanup the static key and
hugetlb_free_vmemmap_enabled() to make code more expressive.

Link: https://lkml.kernel.org/r/20220404074652.68024-3-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

arm64: mm: hugetlb: enable HUGETLB_PAGE_FREE_VMEMMAP for arm64

The feature of minimizing overhead of struct page associated with each
HugeTLB page aims to free its vmemmap pages (used as struct page) to save
memory, where is ~14GB/16GB per 1TB HugeTLB pages (2MB/1GB type). In
short, when a HugeTLB page is allocated or freed, the vmemmap array
representing the range associated with the page will need to be remapped.
When a page is allocated, vmemmap pages are freed after remapping. When a
page is freed, previously discarded vmemmap pages must be allocated before
remapping. More implementations and details can be found here [1].

The infrastructure of freeing vmemmap pages associated with each HugeTLB
page is already there, we can easily enable HUGETLB_PAGE_FREE_VMEMMAP for
arm64, the only thing to be fixed is flush_dcache_page() .

flush_dcache_page() need to be adapted to operate on the head page's flags
since the tail vmemmap pages are mapped with read-only after the feature
is enabled (clear operation is not permitted).

There was some discussions about this in the thread [2], but there was no
conclusion in the end. And I copied the concern proposed by Anshuman to
here and explain why those concern is superfluous. It is safe to enable
it for x86_64 as well as arm64.

1st concern:
'''
But what happens when a hot remove section's vmemmap area (which is
being teared down) is nearby another vmemmap area which is either created
or being destroyed for HugeTLB alloc/free purpose. As you mentioned
HugeTLB pages inside the hot remove section might be safe. But what about
other HugeTLB areas whose vmemmap area shares page table entries with
vmemmap entries for a section being hot removed ? Massive HugeTLB alloc
/use/free test cycle using memory just adjacent to a memory hotplug area,
which is always added and removed periodically, should be able to expose
this problem.
'''

Answer: At the time memory is removed, all HugeTLB pages either have been
migrated away or dissolved. So there is no race between memory hot remove
and free_huge_page_vmemmap(). Therefore, HugeTLB pages inside the hot
remove section is safe. Let's talk your question "what about other
HugeTLB areas whose vmemmap area shares page table entries with vmemmap
entries for a section being hot removed ?", the question is not
established. The minimal granularity size of hotplug memory 128MB (on
arm64, 4k base page), any HugeTLB smaller than 128MB is within a section,
then, there is no share PTE page tables between HugeTLB in this section
and ones in other sections and a HugeTLB page could not cross two
sections. In this case, the section cannot be freed. Any HugeTLB bigger
than 128MB (section size) whose vmemmap pages is an integer multiple of
2MB (PMD-mapped). As long as:

1) HugeTLBs are naturally aligned, power-of-two sizes
2) The HugeTLB size >= the section size
3) The HugeTLB size >= the vmemmap leaf mapping size

Then a HugeTLB will not share any leaf page table entries with *anything
else*, but will share intermediate entries. In this case, at the time
memory is removed, all HugeTLB pages either have been migrated away or
dissolved. So there is also no race between memory hot remove and
free_huge_page_vmemmap().

2nd concern:
'''
differently, not sure if ptdump would require any synchronization.

Dumping an wrong value is probably okay but crashing because a page table
entry is being freed after ptdump acquired the pointer is bad. On arm64,
ptdump() is protected against hotremove via [get|put]_online_mems().
'''

Answer: The ptdump should be fine since vmemmap_remap_free() only
exchanges PTEs or splits the PMD entry (which means allocating a PTE page
table). Both operations do not free any page tables (PTE), so ptdump
cannot run into a UAF on any page tables. The worst case is just dumping
an wrong value.

[1] https://lore.kernel.org/all/20210510030027.56044-1-songmuchun@bytedance.com/
[2] https://lore.kernel.org/all/20210518091826.36937-1-songmuchun@bytedance.com/

[songmuchun@bytedance.com: restructure the code comment inside flush_dcache_page()]
Link: https://lkml.kernel.org/r/20220414072646.21910-1-songmuchun@bytedance.com
Link: https://lkml.kernel.org/r/20220331065640.5777-2-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Barry Song <baohua@kernel.org>
Tested-by: Barry Song <baohua@kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Bodeddula Balasubramaniam <bodeddub@amazon.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Cc: Fam Zheng <fam.zheng@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

arm64: avoid flushing icache multiple times on contiguous HugeTLB

When a contiguous HugeTLB page is mapped, set_pte_at() will be called
CONT_PTES/CONT_PMDS times. Therefore, __sync_icache_dcache() will
flush cache multiple times if the page is executable (to ensure
the I-D cache coherency). However, the first flushing cache already
covers subsequent cache flush operations. So only flusing cache
for the head page if it is a HugeTLB page to avoid redundant cache
flushing. In the next patch, it is also depends on this change
since the tail vmemmap pages of HugeTLB is mapped with read-only
meanning only head page struct can be modified.

Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220302084624.33340-1-songmuchun@bytedance.com
Signed-off-by: Will Deacon <will@kernel.org>

arm64: Rename arm64-internal cache maintenance functions

Although naming across the codebase isn't that consistent, it
tends to follow certain patterns. Moreover, the term "flush"
isn't defined in the Arm Architecture reference manual, and might
be interpreted to mean clean, invalidate, or both for a cache.

Rename arm64-internal functions to make the naming internally
consistent, as well as making it consistent with the Arm ARM, by
specifying whether it applies to the instruction, data, or both
caches, whether the operation is a clean, invalidate, or both.
Also specify which point the operation applies to, i.e., to the
point of unification (PoU), coherency (PoC), or persistence
(PoP).

This commit applies the following sed transformation to all files
under arch/arm64:

"s/\b__flush_cache_range\b/caches_clean_inval_pou_macro/g;"\
"s/\b__flush_icache_range\b/caches_clean_inval_pou/g;"\
"s/\binvalidate_icache_range\b/icache_inval_pou/g;"\
"s/\b__flush_dcache_area\b/dcache_clean_inval_poc/g;"\
"s/\b__inval_dcache_area\b/dcache_inval_poc/g;"\
"s/__clean_dcache_area_poc\b/dcache_clean_poc/g;"\
"s/\b__clean_dcache_area_pop\b/dcache_clean_pop/g;"\
"s/\b__clean_dcache_area_pou\b/dcache_clean_pou/g;"\
"s/\b__flush_cache_user_range\b/caches_clean_inval_user_pou/g;"\
"s/\b__flush_icache_all\b/icache_inval_all_pou/g;"

Note that __clean_dcache_area_poc is deliberately missing a word
boundary check at the beginning in order to match the efistub
symbols in image-vars.h.

Also note that, despite its name, __flush_icache_range operates
on both instruction and data caches. The name change here
reflects that.

No functional change intended.

Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20210524083001.2586635-19-tabba@google.com
Signed-off-by: Will Deacon <will@kernel.org>

arm64: sync_icache_aliases to take end parameter instead of size

To be consistent with other functions with similar names and
functionality in cacheflush.h, cache.S, and cachetlb.rst, change
to specify the range in terms of start and end, as opposed to
start and size.

No functional change intended.

Reported-by: Will Deacon <will@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20210524083001.2586635-17-tabba@google.com
Signed-off-by: Will Deacon <will@kernel.org>

arm64: __clean_dcache_area_pou to take end parameter instead of size

To be consistent with other functions with similar names and
functionality in cacheflush.h, cache.S, and cachetlb.rst, change
to specify the range in terms of start and end, as opposed to
start and size.

No functional change intended.

Reported-by: Will Deacon <will@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20210524083001.2586635-16-tabba@google.com
Signed-off-by: Will Deacon <will@kernel.org>

arm64: __clean_dcache_area_pop to take end parameter instead of size

To be consistent with other functions with similar names and
functionality in cacheflush.h, cache.S, and cachetlb.rst, change
to specify the range in terms of start and end, as opposed to
start and size.

No functional change intended.

Reported-by: Will Deacon <will@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20210524083001.2586635-15-tabba@google.com
Signed-off-by: Will Deacon <will@kernel.org>

arm64: __inval_dcache_area to take end parameter instead of size

To be consistent with other functions with similar names and
functionality in cacheflush.h, cache.S, and cachetlb.rst, change
to specify the range in terms of start and end, as opposed to
start and size.

Because the code is shared with __dma_inv_area, it changes the
parameters for that as well. However, __dma_inv_area is local to
cache.S, so no other users are affected.

No functional change intended.

Reported-by: Will Deacon <will@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20210524083001.2586635-11-tabba@google.com
Signed-off-by: Will Deacon <will@kernel.org>

arm64: Fix race condition on PG_dcache_clean in __sync_icache_dcache()

To ensure that instructions are observable in a new mapping, the arm64
set_pte_at() implementation cleans the D-cache and invalidates the
I-cache to the PoU. As an optimisation, this is only done on executable
mappings and the PG_dcache_clean page flag is set to avoid future cache
maintenance on the same page.

When two different processes map the same page (e.g. private executable
file or shared mapping) there's a potential race on checking and setting
PG_dcache_clean via set_pte_at() -> __sync_icache_dcache(). While on the
fault paths the page is locked (PG_locked), mprotect() does not take the
page lock. The result is that one process may see the PG_dcache_clean
flag set but the I/D cache maintenance not yet performed.

Avoid test_and_set_bit(PG_dcache_clean) in favour of separate test_bit()
and set_bit(). In the rare event of a race, the cache maintenance is
done twice.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: <stable@vger.kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210514095001.13236-1-catalin.marinas@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

mm: introduce page_size()

Patch series "Make working with compound pages easier", v2.

These three patches add three helpers and convert the appropriate
places to use them.

This patch (of 3):

It's unnecessarily hard to find out the size of a potentially huge page.
Replace 'PAGE_SIZE << compound_order(page)' with page_size(page).

Link: http://lkml.kernel.org/r/20190721104612.19120-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation this program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
public license along with this program if not see http www gnu org
licenses

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 503 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Enrico Weigelt <info@metux.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190602204653.811534538@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arm64: Do not issue IPIs for user executable ptes

Commit 3b8c9f1cdfc5 ("arm64: IPI each CPU after invalidating the I-cache
for kernel mappings") was aimed at fixing the I-cache invalidation for
kernel mappings. However, it inadvertently caused all cache maintenance
for user mappings via set_pte_at() -> __sync_icache_dcache() ->
sync_icache_aliases() to call kick_all_cpus_sync().

Reported-by: Shijith Thotton <sthotton@marvell.com>
Tested-by: Shijith Thotton <sthotton@marvell.com>
Reported-by: Wandun Chen <chenwandun@huawei.com>
Fixes: 3b8c9f1cdfc5 ("arm64: IPI each CPU after invalidating the I-cache for kernel mappings")
Cc: <stable@vger.kernel.org> # 4.19.x-
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arm64: mm: Export __sync_icache_dcache() for xen-privcmd

The xen-privcmd driver, which can be modular, calls set_pte_at()
which in turn may call __sync_icache_dcache().

The call to __sync_icache_dcache() may be optimised out because it is
conditional on !pte_special(), and xen-privcmd calls pte_mkspecial().
But it seems unwise to rely on this optimisation.

Fixes: 3ad0876554ca ("xen/privcmd: add IOCTL_PRIVCMD_MMAP_RESOURCE")
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arm64: mm: Export __flush_icache_range() to modules

lkdtm calls flush_icache_range(), which results in an out-of-line call
to __flush_icache_range(), which is not exported to modules.

Export the symbol to modules to fix this build breakage.

Fixes: 3b8c9f1cdfc5 ("arm64: IPI each CPU after invalidating the I-cache for kernel mappings")
Signed-off-by: Will Deacon <will.deacon@arm.com>

arm64: mm: drop addr parameter from sync icache and dcache

The addr parameter isn't used for anything. Let's simplify and get rid of
it, like arm.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arm64: fix pmem interface definition

Defining the two functions as 'static inline' and exporting them
leads to the interesting case where we can use the interface
from loadable modules, but not from built-in drivers, as shown
in this link failure:

vers/nvdimm/claim.o: In function `nsio_rw_bytes':
claim.c:(.text+0x1b8): undefined reference to `arch_invalidate_pmem'
drivers/nvdimm/pmem.o: In function `pmem_dax_flush':
pmem.c:(.text+0x11c): undefined reference to `arch_wb_cache_pmem'
drivers/nvdimm/pmem.o: In function `pmem_make_request':
pmem.c:(.text+0x5a4): undefined reference to `arch_invalidate_pmem'
pmem.c:(.text+0x650): undefined reference to `arch_invalidate_pmem'
pmem.c:(.text+0x6d4): undefined reference to `arch_invalidate_pmem'

This removes the bogus 'static inline'.

Fixes: d50e071fdaa3 ("arm64: Implement pmem API support")
Acked-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64: Implement pmem API support

Add a clean-to-point-of-persistence cache maintenance helper, and wire
up the basic architectural support for the pmem driver based on it.

Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
[catalin.marinas@arm.com: move arch_*_pmem() functions to arch/arm64/mm/flush.c]
[catalin.marinas@arm.com: change dmb(sy) to dmb(osh)]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64: cache: Merge cachetype.h into cache.h

cachetype.h and cache.h are small and both obviously related to caches.
Merge them together to reduce clutter.

Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64: cache: Remove support for ASID-tagged VIVT I-caches

As a recent change to ARMv8, ASID-tagged VIVT I-caches are removed
retrospectively from the architecture. Consequently, we don't need to
support them in Linux either.

Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64: Remove I-cache invalidation from flush_cache_range()

The flush_cache_range() function (similarly for flush_cache_page()) is
called when the kernel is changing an existing VA->PA mapping range to
either a new PA or to different attributes. Since ARMv8 has PIPT-like
D-caches, this function does not need to perform any D-cache
maintenance. The I-cache maintenance is already handled via set_pte_at()
and flush_cache_range() cannot anyway guarantee that there are no cache
lines left after invalidation due to the speculative loads.

This patch makes flush_cache_range() a no-op.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64: Add uprobe support

This patch adds support for uprobe on ARM64 architecture.

Unit tests for following have been done so far and they have been found
working
1. Step-able instructions, like sub, ldr, add etc.
2. Simulation-able like ret, cbnz, cbz etc.
3. uretprobe
4. Reject-able instructions like sev, wfe etc.
5. trapped and abort xol path
6. probe at unaligned user address.
7. longjump test cases

Currently it does not support aarch32 instruction probing.

Signed-off-by: Pratyush Anand <panand@redhat.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64: mm: drop fixup_init() and mm.h

There is only fixup_init() in mm.h , and it is only called
in free_initmem(), so move the codes from fixup_init() into
free_initmem(), then drop fixup_init() and mm.h.

Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arm64: mm: remove page_mapping check in __sync_icache_dcache

__sync_icache_dcache unconditionally skips the cache maintenance for
anonymous pages, under the assumption that flushing is only required in
the presence of D-side aliases [see 7249b79f6b4cc ("arm64: Do not flush
the D-cache for anonymous pages")].

Unfortunately, this breaks migration of anonymous pages holding
self-modifying code, where userspace cannot be reasonably expected to
reissue maintenance instructions in response to a migration.

This patch fixes the problem by removing the broken page_mapping(page)
check from the cache syncing code, otherwise we may end up fetching and
executing stale instructions from the PoU.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: <stable@vger.kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arm64: mm: allow preemption in copy_to_user_page

Currently we disable preemption in copy_to_user_page; a behaviour that
we inherited from the 32-bit arm code. This was necessary for older
cores without broadcast data cache maintenance, and ensured that cache
lines were dirtied and cleaned by the same CPU. On these systems dirty
cache line migration was not possible, so this was sufficient to
guarantee coherency.

On contemporary systems, cache coherence protocols permit (dirty) cache
lines to migrate between CPUs as a result of speculation, prefetching,
and other behaviours. To account for this, in ARMv8 data cache
maintenance operations are broadcast and affect all data caches in the
domain associated with the VA (i.e. ISH for kernel and user mappings).

In __switch_to we ensure that tasks can be safely migrated in the middle
of a maintenance sequence, using a dsb(ish) to ensure prior explicit
memory accesses are observed and cache maintenance operations are
completed before a task can be run on another CPU.

Given the above, it is not necessary to disable preemption in
copy_to_user_page. This patch removes the preempt_{disable,enable}
calls, permitting preemption.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64, thp: remove infrastructure for handling splitting PMDs

With new refcounting we don't need to mark PMDs splitting. Let's drop
code to handle this.

pmdp_splitting_flush() is not needed too: on splitting PMD we will do
pmdp_clear_flush() + set_pte_at(). pmdp_clear_flush() will do IPI as
needed for fast_gup.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arm64: Use PoU cache instr for I/D coherency

In systems with three levels of cache(PoU at L1 and PoC at L3),
PoC cache flush instructions flushes L2 and L3 caches which could affect
performance.
For cache flushes for I and D coherency, PoU should suffice.
So changing all I and D coherency related cache flushes to PoU.

Introduced a new __clean_dcache_area_pou API for dcache flush till PoU
and provided a common macro for __flush_dcache_area and
__clean_dcache_area_pou.

Also, now in __sync_icache_dcache, icache invalidation for non-aliasing
VIPT icache is done only for that particular page instead of the earlier
__flush_icache_all.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ashok Kumar <ashoks@broadcom.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arm64: force CONFIG_SMP=y and remove redundant #ifdefs

Nobody seems to be producing !SMP systems anymore, so this is just
becoming a source of kernel bugs, particularly if people want to use
coherent DMA with non-shared pages.

This patch forces CONFIG_SMP=y for arm64, removing a modest amount of
code in the process.

Signed-off-by: Will Deacon <will.deacon@arm.com>

arm64: kill flush_cache_all()

The documented semantics of flush_cache_all are not possible to provide
for arm64 (short of flushing the entire physical address space by VA),
and there are currently no users; KVM uses VA maintenance exclusively,
cpu_reset is never called, and the only two users outside of arch code
cannot be built for arm64.

While cpu_soft_reset and related functions (which call flush_cache_all)
were thought to be useful for kexec, their current implementations only
serve to mask bugs. For correctness kexec will need to perform
maintenance by VA anyway to account for system caches, line migration,
and other subtleties of the cache architecture. As the extent of this
cache maintenance will be kexec-specific, it should probably live in the
kexec code.

This patch removes flush_cache_all, and related unused components,
preventing further abuse.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Geoff Levand <geoff@infradead.org>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64: mm: enable RCU fast_gup

Activate the RCU fast_gup for ARM64. We also need to force THP splits to
broadcast an IPI s.t. we block in the fast_gup page walker. As THP
splits are comparatively rare, this should not lead to a noticeable
performance degradation.

Some pre-requisite functions pud_write and pud_page are also added.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Steve Capper <steve.capper@linaro.org>
Tested-by: Dann Frazier <dann.frazier@canonical.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arm64: mm: Make icache synchronisation logic huge page aware

The __sync_icache_dcache routine will only flush the dcache for the
first page of a compound page, potentially leading to stale icache
data residing further on in a hugetlb page.

This patch addresses this issue by taking into consideration the
order of the page when flushing the dcache.

Reported-by: Mark Brown <broonie@linaro.org>
Tested-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Steve Capper <steve.capper@linaro.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: <stable@vger.kernel.org> # v3.11+

arm64: Remove __flush_dcache_page()

This function is only used in __sync_icache_dcache(), so remove it and
call __flush_dcache_area() directly. The flush_icache_user_range()
function is not used in the arm64 kernel.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Will Deacon <will.deacon@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>

arm64: Do not flush the D-cache for anonymous pages

The D-cache on AArch64 is VIPT non-aliasing, so there is no need to
flush it for anonymous pages.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Will Deacon <will.deacon@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>

arm64: Avoid cache flushing in flush_dcache_page()

The flush_dcache_page() function is called when the kernel modified a
page cache page. Since the D-cache on AArch64 does not have aliases
this function can simply mark the page as dirty for later flushing via
set_pte_at()/__sync_icache_dcache() if the page is executable (to ensure
the I-D cache coherency).

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Will Deacon <will.deacon@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>

arm64: Convert empty flush_cache_{mm,page} functions to static inline

These functions are empty, just make them static inline in the header.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64: Cache maintenance routines

The patch adds functionality required for cache maintenance. The AArch64
architecture mandates non-aliasing VIPT or PIPT D-cache and VIPT (may
have aliases) or ASID-tagged VIVT I-cache. Cache maintenance operations
are automatically broadcast in hardware between CPUs.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>