linux-stable.git/arch/arc, branch linux-4.17.y

ARC: Improve cmpxchg syscall implementation

2018-08-24T11:07:05+00:00

[ Upstream commit e8708786d4fe21c043d38d760f768949a3d71185 ]

This is used in configs lacking hardware atomics to emulate atomic r-m-w
for user space, implemented by disabling preemption in kernel.

However there are issues in current implementation:

1. Process not terminated if invalid user pointer passed:
   i.e. __get_user() failed.

2. The reason for this patch was __put_user() failure not being handled
   either, specifically for the COW break scenario.
   The zero page is initially wired up and read from __get_user()
   succeeds. A subsequent write by __put_user() induces a
   Protection Violation, but COW can't finish as Linux page fault
   handler is disabled due to preempt disable.
   And what's worse is we silently return the stale value to user space.
   Fix this specific case by re-enabling preemption and explicitly
   fixing up the fault and retrying the whole sequence over.

Cc: Max Filippov 
Cc: linux-arch@vger.kernel.org
Signed-off-by: Alexey Brodkin 
Signed-off-by: Peter Zijlstra 
Signed-off-by: Vineet Gupta 
[vgupta: rewrote the changelog]
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

ARC: [plat-hsdk]: Configure APB GPIO controller on ARC HSDK platform

2018-08-24T11:07:04+00:00

[ Upstream commit ec58ba16e174d7ca24c8955a21cd0a53e0c32fdf ]

In case of HSDK we have intermediate INTC in for of DW APB GPIO controller
which is used as a de-bounce logic for interrupt wires that come from
outside the board.

We cannot use existing "irq-dw-apb-ictl" driver here because all input
lines are routed to corresponding output lines but not muxed into one
line (this is configured in RTL and we cannot change this in software).

But even if we add such a feature to "irq-dw-apb-ictl" driver that won't
benefit us as higher-level INTC (in case of HSDK it is IDU) anyways has
per-input control so adding fully-controller intermediate INTC will only
bring some overhead on interrupt processing but no other benefits.

Thus we just do one-time configuration of DW APB GPIO controller and
forget about it.

Based on implementation available on arch/arc/plat-axs10x/axs10x.c file.

Acked-by: Alexey Brodkin 
Signed-off-by: Gustavo Pimentel 
Signed-off-by: Vineet Gupta 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

ARC: Enable machine_desc->init_per_cpu for !CONFIG_SMP

2018-08-24T11:06:45+00:00

[ Upstream commit 2f24ef7413a4d91657ef04e77c27ce0b313e6c95 ]

machine_desc->init_per_cpu() hook is supposed to be per cpu
initialization and would seem to apply  equally to UP and/or SMP.
Infact the comment in header file seems to suggest it works for
UP too, which was not the case and this patch.

This enables !CONFIG_SMP build for platforms such as hsdk.

Signed-off-by: Alexey Brodkin 
Signed-off-by: Vineet Gupta 
[vgupta: trimmeed changelog]
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

ARC: Explicitly add -mmedium-calls to CFLAGS

2018-08-24T11:06:38+00:00

[ Upstream commit 74c11e300c103af47db5b658fdcf28002421e250 ]

GCC built for arc*-*-linux has "-mmedium-calls" implicitly enabled by default
thus we don't see any problems during Linux kernel compilation.
----------------------------->8------------------------
arc-linux-gcc -mcpu=arc700 -Q --help=target | grep calls
  -mlong-calls                          [disabled]
  -mmedium-calls                        [enabled]
----------------------------->8------------------------

But if we try to use so-called Elf32 toolchain with GCC configured for
arc*-*-elf* then we'd see the following failure:
----------------------------->8------------------------
init/do_mounts.o: In function 'init_rootfs':
do_mounts.c:(.init.text+0x108): relocation truncated to fit: R_ARC_S21W_PCREL
against symbol 'unregister_filesystem' defined in .text section in fs/filesystems.o

arc-elf32-ld: final link failed: Symbol needs debug section which does not exist
make: *** [vmlinux] Error 1
----------------------------->8------------------------

That happens because neither "-mmedium-calls" nor "-mlong-calls" are enabled in
Elf32 GCC:
----------------------------->8------------------------
arc-elf32-gcc -mcpu=arc700 -Q --help=target | grep calls
  -mlong-calls                          [disabled]
  -mmedium-calls                        [disabled]
----------------------------->8------------------------

Now to make it possible to use Elf32 toolchain for building Linux kernel
we're explicitly add "-mmedium-calls" to CFLAGS.

And since we add "-mmedium-calls" to the global CFLAGS there's no point in
having per-file copies thus removing them.

Signed-off-by: Alexey Brodkin 
Signed-off-by: Vineet Gupta 

Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

ARC: mm: allow mprotect to make stack mappings executable

2018-07-25T09:26:08+00:00

commit 93312b6da4df31e4102ce5420e6217135a16c7ea upstream.

mprotect(EXEC) was failing for stack mappings as default vm flags was
missing MAYEXEC.

This was triggered by glibc test suite nptl/tst-execstack testcase

What is surprising is that despite running LTP for years on, we didn't
catch this issue as it lacks a directed test case.

gcc dejagnu tests with nested functions also requiring exec stack work
fine though because they rely on the GNU_STACK segment spit out by
compiler and handled in kernel elf loader.

This glibc case is different as the stack is non exec to begin with and
a dlopen of shared lib with GNU_STACK segment triggers the exec stack
proceedings using a mprotect(PROT_EXEC) which was broken.

CC: stable@vger.kernel.org
Signed-off-by: Vineet Gupta 
Signed-off-by: Greg Kroah-Hartman

ARC: configs: Remove CONFIG_INITRAMFS_SOURCE from defconfigs

2018-07-25T09:26:08+00:00

commit 64234961c145606b36eaa82c47b11be842b21049 upstream.

We used to have pre-set CONFIG_INITRAMFS_SOURCE with local path
to intramfs in ARC defconfigs. This was quite convenient for
in-house development but not that convenient for newcomers
who obviusly don't have folders like "arc_initramfs" next to
the Linux source tree. Which leads to quite surprising failure
of defconfig building:
------------------------------->8-----------------------------
  ../scripts/gen_initramfs_list.sh: Cannot open '../../arc_initramfs_hs/'
../usr/Makefile:57: recipe for target 'usr/initramfs_data.cpio.gz' failed
make[2]: *** [usr/initramfs_data.cpio.gz] Error 1
------------------------------->8-----------------------------

So now when more and more people start to deal with our defconfigs
let's make their life easier with removal of CONFIG_INITRAMFS_SOURCE.

Signed-off-by: Alexey Brodkin 
Cc: Kevin Hilman 
Cc: stable@vger.kernel.org
Signed-off-by: Alexey Brodkin 
Signed-off-by: Vineet Gupta 
Signed-off-by: Greg Kroah-Hartman

ARC: Fix CONFIG_SWAP

2018-07-25T09:26:08+00:00

commit 6e3761145a9ba3ce267c330b6bff51cf6a057b06 upstream.

swap was broken on ARC due to silly copy-paste issue.

We encode offset from swapcache page in __swp_entry() as (off << 13) but
were not decoding back in __swp_offset() as (off >> 13) - it was still
(off << 13).

This finally fixes swap usage on ARC.

| # mkswap /dev/sda2
|
| # swapon -a -e /dev/sda2
| Adding 500728k swap on /dev/sda2.  Priority:-2 extents:1 across:500728k
|
| # free
|              total       used       free     shared    buffers     cached
| Mem:        765104      13456     751648       4736          8       4736
| -/+ buffers/cache:       8712     756392
| Swap:       500728          0     500728

Cc: stable@vger.kernel.org
Signed-off-by: Alexey Brodkin 
Signed-off-by: Vineet Gupta 
Signed-off-by: Greg Kroah-Hartman

ARCv2: [plat-hsdk]: Save accl reg pair by default

2018-07-25T09:26:07+00:00

commit af1fc5baa724c63ce1733dfcf855bad5ef6078e3 upstream.

This manifsted as strace segfaulting on HSDK because gcc was targetting
the accumulator registers as GPRs, which kernek was not saving/restoring
by default.

Cc: stable@vger.kernel.org   #4.14+
Signed-off-by: Vineet Gupta 
Signed-off-by: Greg Kroah-Hartman

kbuild: mark $(targets) as .SECONDARY and remove .PRECIOUS markers

2018-04-07T10:04:02+00:00

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: Masahiro Yamada 
Acked-by: Frank Rowand 
Acked-by: Ingo Molnar

Merge branch 'akpm' (patches from Andrew)

2018-04-06T21:19:26+00:00

Merge updates from Andrew Morton:

 - a few misc things

 - ocfs2 updates

 - the v9fs maintainers have been missing for a long time. I've taken
   over v9fs patch slinging.

 - most of MM

* emailed patches from Andrew Morton : (116 commits)
  mm,oom_reaper: check for MMF_OOM_SKIP before complaining
  mm/ksm: fix interaction with THP
  mm/memblock.c: cast constant ULLONG_MAX to phys_addr_t
  headers: untangle kmemleak.h from mm.h
  include/linux/mmdebug.h: make VM_WARN* non-rvals
  mm/page_isolation.c: make start_isolate_page_range() fail if already isolated
  mm: change return type to vm_fault_t
  mm, oom: remove 3% bonus for CAP_SYS_ADMIN processes
  mm, page_alloc: wakeup kcompactd even if kswapd cannot free more memory
  kernel/fork.c: detect early free of a live mm
  mm: make counting of list_lru_one::nr_items lockless
  mm/swap_state.c: make bool enable_vma_readahead and swap_vma_readahead() static
  block_invalidatepage(): only release page if the full page was invalidated
  mm: kernel-doc: add missing parameter descriptions
  mm/swap.c: remove @cold parameter description for release_pages()
  mm/nommu: remove description of alloc_vm_area
  zram: drop max_zpage_size and use zs_huge_class_size()
  zsmalloc: introduce zs_huge_class_size()
  mm: fix races between swapoff and flush dcache
  fs/direct-io.c: minor cleanups in do_blockdev_direct_IO
  ...