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  1. Apr 27, 2018
  3. Apr 11, 2018
  5. Apr 10, 2018
  7. Apr 08, 2018
  9. Apr 07, 2018
    • Masahiro Yamada's avatar
      kbuild: mark $(targets) as .SECONDARY and remove .PRECIOUS markers · 54a702f7
      Masahiro Yamada authored 
      

GNU Make automatically deletes intermediate files that are updated
in a chain of pattern rules.

Example 1) %.dtb.o <- %.dtb.S <- %.dtb <- %.dts
Example 2) %.o <- %.c <- %.c_shipped

A couple of makefiles mark such targets as .PRECIOUS to prevent Make
from deleting them, but the correct way is to use .SECONDARY.

  .SECONDARY
    Prerequisites of this special target are treated as intermediate
    files but are never automatically deleted.

  .PRECIOUS
    When make is interrupted during execution, it may delete the target
    file it is updating if the file was modified since make started.
    If you mark the file as precious, make will never delete the file
    if interrupted.

Both can avoid deletion of intermediate files, but the difference is
the behavior when Make is interrupted; .SECONDARY deletes the target,
but .PRECIOUS does not.

The use of .PRECIOUS is relatively rare since we do not want to keep
partially constructed (possibly corrupted) targets.

Another difference is that .PRECIOUS works with pattern rules whereas
.SECONDARY does not.

  .PRECIOUS: $(obj)/%.lex.c

works, but

  .SECONDARY: $(obj)/%.lex.c

has no effect.  However, for the reason above, I do not want to use
.PRECIOUS which could cause obscure build breakage.

The targets specified as .SECONDARY must be explicit.  $(targets)
contains all targets that need to include .*.cmd files.  So, the
intermediates you want to keep are mostly in there.  Therefore, mark
$(targets) as .SECONDARY.  It means primary targets are also marked
as .SECONDARY, but I do not see any drawback for this.

I replaced some .SECONDARY / .PRECIOUS markers with 'targets'.  This
will make Kbuild search for non-existing .*.cmd files, but this is
not a noticeable performance issue.

Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: default avatarFrank Rowand <frowand.list@gmail.com>
Acked-by: default avatarIngo Molnar <mingo@kernel.org>
      54a702f7
  11. Apr 06, 2018
    • Russell King's avatar
      ARM: sa1100/simpad: switch simpad CF to use gpiod APIs · 64b2f129
      Russell King authored 
      

Switch simpad's CF implementation to use the gpiod APIs.  The inverted
detection is handled using gpiolib's native inversion abilities.

Signed-off-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
      64b2f129
    • Russell King's avatar
      ARM: sa1100/shannon: convert to generic CF sockets · b51af865
      Russell King authored 
      

Convert shannon to use the generic CF socket support.

Signed-off-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
      b51af865
    • Russell King's avatar
      ARM: sa1100/nanoengine: convert to generic CF sockets · 80c799db
      Russell King authored 
      

Convert nanoengine to use the generic CF socket support.
Makefile fix from Arnd Bergmann <arnd@arndb.de>.

Signed-off-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
      80c799db
    • Huang Ying's avatar
      mm: fix races between swapoff and flush dcache · cb9f753a
      Huang Ying authored 
      Thanks to commit 4b3ef9da ("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: default avatar"Huang, Ying" <ying.huang@intel.com>
Reviewed-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Chen Liqin <liqin.linux@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chris Zankel <chris@zankel.net>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      cb9f753a
    • Huacai Chen's avatar
      zboot: fix stack protector in compressed boot phase · 7bbaf27d
      Huacai Chen authored 
      Calling __stack_chk_guard_setup() in decompress_kernel() is too late
that stack checking always fails for decompress_kernel() itself.  So
remove __stack_chk_guard_setup() and initialize __stack_chk_guard before
we call decompress_kernel().

Original code comes from ARM but also used for MIPS and SH, so fix them
together.  If without this fix, compressed booting of these archs will
fail because stack checking is enabled by default (>=4.16).

Link: http://lkml.kernel.org/r/1522226933-29317-1-git-send-email-chenhc@lemote.com


Fixes: 8779657d ("stackprotector: Introduce CONFIG_CC_STACKPROTECTOR_STRONG")
Signed-off-by: default avatarHuacai Chen <chenhc@lemote.com>
Acked-by: default avatarJames Hogan <jhogan@kernel.org>
Acked-by: default avatarKees Cook <keescook@chromium.org>
Acked-by: default avatarRich Felker <dalias@libc.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      7bbaf27d
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