linux-stable.git/arch/mips/mm/cache.c, branch linux-5.2.y

MIPS: Delete unused flush_cache_sigtramp()

2019-02-07T20:59:45+00:00

Commit adcc81f148d7 ("MIPS: math-emu: Write-protect delay slot emulation
pages") left flush_cache_sigtramp() unused. Delete the dead code.

Signed-off-by: Paul Burton 
Cc: Davidlohr Bueso 
Cc: linux-mips@vger.kernel.org

Remove 'type' argument from access_ok() function

2019-01-04T02:57:57+00:00

Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.

It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access.  But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.

A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model.  And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.

This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.

There were a couple of notable cases:

 - csky still had the old "verify_area()" name as an alias.

 - the iter_iov code had magical hardcoded knowledge of the actual
   values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
   really used it)

 - microblaze used the type argument for a debug printout

but other than those oddities this should be a total no-op patch.

I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something.  Any missed conversion should be trivially fixable, though.

Signed-off-by: Linus Torvalds

MIPS: simplify CONFIG_DMA_NONCOHERENT ifdefs

2018-06-24T16:26:02+00:00

CONFIG_DMA_MAYBE_COHERENT already selects CONFIG_DMA_NONCOHERENT, so we
can remove the extra conditions.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Paul Burton 
Patchwork: https://patchwork.linux-mips.org/patch/19529/
Signed-off-by: Paul Burton 
Cc: Florian Fainelli 
Cc: David Daney 
Cc: Kevin Cernekee 
Cc: Jiaxun Yang 
Cc: Tom Bogendoerfer 
Cc: Huacai Chen 
Cc: iommu@lists.linux-foundation.org
Cc: linux-mips@linux-mips.org

mm: fix races between swapoff and flush dcache

2018-04-06T04:36:26+00:00

Thanks to commit 4b3ef9daa4fc ("mm/swap: split swap cache into 64MB
trunks"), after swapoff the address_space associated with the swap
device will be freed.  So page_mapping() users which may touch the
address_space need some kind of mechanism to prevent the address_space
from being freed during accessing.

The dcache flushing functions (flush_dcache_page(), etc) in architecture
specific code may access the address_space of swap device for anonymous
pages in swap cache via page_mapping() function.  But in some cases
there are no mechanisms to prevent the swap device from being swapoff,
for example,

  CPU1					CPU2
  __get_user_pages()			swapoff()
    flush_dcache_page()
      mapping = page_mapping()
        ...				  exit_swap_address_space()
        ...				    kvfree(spaces)
        mapping_mapped(mapping)

The address space may be accessed after being freed.

But from cachetlb.txt and Russell King, flush_dcache_page() only care
about file cache pages, for anonymous pages, flush_anon_page() should be
used.  The implementation of flush_dcache_page() in all architectures
follows this too.  They will check whether page_mapping() is NULL and
whether mapping_mapped() is true to determine whether to flush the
dcache immediately.  And they will use interval tree (mapping->i_mmap)
to find all user space mappings.  While mapping_mapped() and
mapping->i_mmap isn't used by anonymous pages in swap cache at all.

So, to fix the race between swapoff and flush dcache, __page_mapping()
is add to return the address_space for file cache pages and NULL
otherwise.  All page_mapping() invoking in flush dcache functions are
replaced with page_mapping_file().

[akpm@linux-foundation.org: simplify page_mapping_file(), per Mike]
Link: http://lkml.kernel.org/r/20180305083634.15174-1-ying.huang@intel.com
Signed-off-by: "Huang, Ying" 
Reviewed-by: Andrew Morton 
Cc: Minchan Kim 
Cc: Michal Hocko 
Cc: Johannes Weiner 
Cc: Mel Gorman 
Cc: Dave Hansen 
Cc: Chen Liqin 
Cc: Russell King 
Cc: Yoshinori Sato 
Cc: "James E.J. Bottomley" 
Cc: Guan Xuetao 
Cc: "David S. Miller" 
Cc: Chris Zankel 
Cc: Vineet Gupta 
Cc: Ley Foon Tan 
Cc: Ralf Baechle 
Cc: Andi Kleen 
Cc: Mike Rapoport 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

MIPS: Remove __invalidate_kernel_vmap_range

2017-08-29T13:21:55+00:00

The __invalidate_kernel_vmap_range function pointer global variable
isn't used anywhere. Remove it.

Signed-off-by: Paul Burton 
Cc: linux-mips@linux-mips.org
Cc: trivial@kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/17174/
Signed-off-by: Ralf Baechle

MIPS: Include asm/setup.h for cpu_cache_init()

2017-08-29T13:21:54+00:00

arch/mips/mm/cache.c provides our implementation of the cpu_cache_init()
function, but doesn't include the asm/setup.h header which declares it.
This leads to a warning from sparse:

  arch/mips/mm/cache.c:274:6: warning: symbol 'cpu_cache_init' was not
    declared. Should it be static?

Fix this by including asm/setup.h to get the declaration of
cpu_cache_init().

Signed-off-by: Paul Burton 
Cc: linux-mips@linux-mips.org
Cc: trivial@kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/17168/
Signed-off-by: Ralf Baechle

KVM: MIPS/Emulate: Adapt T&E CACHE emulation for Octeon

2017-03-28T14:36:17+00:00

Cache management is implemented separately for Cavium Octeon CPUs, so
r4k_blast_[id]cache aren't available. Instead for Octeon perform a local
icache flush using local_flush_icache_range(), and for other platforms
which don't use c-r4k.c use __flush_cache_all() / flush_icache_all().

Signed-off-by: James Hogan 
Cc: Paolo Bonzini 
Cc: "Radim Krčmář" 
Cc: Ralf Baechle 
Cc: David Daney 
Cc: Andreas Herrmann 
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

MIPS: mm: Audit and remove any unnecessary uses of module.h

2016-10-04T23:31:20+00:00

Historically a lot of these existed because we did not have
a distinction between what was modular code and what was providing
support to modules via EXPORT_SYMBOL and friends.  That changed
when we forked out support for the latter into the export.h file.

This means we should be able to reduce the usage of module.h
in code that is obj-y Makefile or bool Kconfig.  The advantage
in doing so is that module.h itself sources about 15 other headers;
adding significantly to what we feed cpp, and it can obscure what
headers we are effectively using.

Since module.h was the source for init.h (for __init) and for
export.h (for EXPORT_SYMBOL) we consider each obj-y/bool instance
for the presence of either and replace as needed.

Signed-off-by: Paul Gortmaker 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14033/
Signed-off-by: Ralf Baechle

MIPS: cacheflush: Use __flush_icache_user_range()

2016-10-04T14:13:57+00:00

The cacheflush(2) system call uses flush_icache_range() to flush a range
of usermode addresses from the icache, so change it to utilise the new
__flush_icache_user_range() API to allow the more generic
flush_icache_range() to be changed to work on kernel addresses only.

Signed-off-by: James Hogan 
Cc: Leonid Yegoshin 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14153/
Signed-off-by: Ralf Baechle

MIPS: c-r4k: Split user/kernel flush_icache_range()

2016-10-04T14:13:57+00:00

flush_icache_range() is used for both user addresses (i.e.
cacheflush(2)), and kernel addresses (as the API documentation
describes).

This isn't really suitable however for Enhanced Virtual Addressing (EVA)
where cache operations on usermode addresses must use a different
instruction, and the protected cache ops assume user addresses, making
flush_icache_range() ineffective on kernel addresses.

Split out a new __flush_icache_user_range() and
__local_flush_icache_user_range() for users which actually want to flush
usermode addresses (note that flush_icache_user_range() already exists
on various architectures but with different arguments).

The implementation of flush_icache_range() will be changed in an
upcoming commit to use unprotected normal cache ops so as to always work
on the kernel mode address space.

Signed-off-by: James Hogan 
Cc: Leonid Yegoshin 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14152/
Signed-off-by: Ralf Baechle