linux-stable.git/include/asm-generic, branch v3.16.52

asm/sections: add helpers to check for section data

2017-11-26T13:50:15+00:00

commit 979559362516bb0f5424505c607210ac054e30ae upstream.

Add a helper to check if an object (given an address and a size) is part
of a section (given beginning and end addresses).  For convenience, also
provide a helper that performs this check for __init data using the
__init_begin and __init_end limits.

Signed-off-by: Thierry Reding 
Cc: Arnd Bergmann 
Cc: Greg Kroah-Hartman 
Cc: Joe Perches 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Ben Hutchings

cpumask: fix spurious cpumask_of_node() on non-NUMA multi-node configs

2017-11-11T13:33:32+00:00

commit b339752d054fb32863418452dff350a1086885b1 upstream.

When !NUMA, cpumask_of_node(@node) equals cpu_online_mask regardless of
@node.  The assumption seems that if !NUMA, there shouldn't be more than
one node and thus reporting cpu_online_mask regardless of @node is
correct.  However, that assumption was broken years ago to support
DISCONTIGMEM and whether a system has multiple nodes or not is
separately controlled by NEED_MULTIPLE_NODES.

This means that, on a system with !NUMA && NEED_MULTIPLE_NODES,
cpumask_of_node() will report cpu_online_mask for all possible nodes,
indicating that the CPUs are associated with multiple nodes which is an
impossible configuration.

This bug has been around forever but doesn't look like it has caused any
noticeable symptoms.  However, it triggers a WARN recently added to
workqueue to verify NUMA affinity configuration.

Fix it by reporting empty cpumask on non-zero nodes if !NUMA.

Signed-off-by: Tejun Heo 
Reported-and-tested-by: Geert Uytterhoeven 
Signed-off-by: Linus Torvalds 
Signed-off-by: Ben Hutchings

asm-generic: make get_user() clear the destination on errors

2016-11-20T01:17:26+00:00

commit 9ad18b75c2f6e4a78ce204e79f37781f8815c0fa upstream.

both for access_ok() failures and for faults halfway through

Signed-off-by: Al Viro 
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings

asm-generic: make copy_from_user() zero the destination properly

2016-11-20T01:17:25+00:00

commit 2545e5da080b4839dd859e3b09343a884f6ab0e3 upstream.

... in all cases, including the failing access_ok()

Note that some architectures using asm-generic/uaccess.h have
__copy_from_user() not zeroing the tail on failure halfway
through.  This variant works either way.

Signed-off-by: Al Viro 
Signed-off-by: Ben Hutchings

sched/preempt: Fix preempt_count manipulations

2016-08-22T21:38:00+00:00

commit 2e636d5e66c35dfcbaf617aa8fa963f6847478fe upstream.

Vikram reported that his ARM64 compiler managed to 'optimize' away the
preempt_count manipulations in code like:

	preempt_enable_no_resched();
	put_user();
	preempt_disable();

Irrespective of that fact that that is horrible code that should be
fixed for many reasons, it does highlight a deficiency in the generic
preempt_count manipulators. As it is never right to combine/elide
preempt_count manipulations like this.

Therefore sprinkle some volatile in the two generic accessors to
ensure the compiler is aware of the fact that the preempt_count is
observed outside of the regular program-order view and thus cannot be
optimized away like this.

x86; the only arch not using the generic code is not affected as we
do all this in asm in order to use the segment base per-cpu stuff.

Reported-by: Vikram Mulukutla 
Tested-by: Vikram Mulukutla 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Fixes: a787870924db ("sched, arch: Create asm/preempt.h")
Link: http://lkml.kernel.org/r/20160516131751.GH3205@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar 
[bwh: Backported to 3.16: use ACCESS_ONCE() instead of READ_ONCE()]
Signed-off-by: Ben Hutchings

bitops: Do not default to __clear_bit() for __clear_bit_unlock()

2016-04-30T22:06:03+00:00

commit f75d48644c56a31731d17fa693c8175328957e1d upstream.

__clear_bit_unlock() is a special little snowflake. While it carries the
non-atomic '__' prefix, it is specifically documented to pair with
test_and_set_bit() and therefore should be 'somewhat' atomic.

Therefore the generic implementation of __clear_bit_unlock() cannot use
the fully non-atomic __clear_bit() as a default.

If an arch is able to do better; is must provide an implementation of
__clear_bit_unlock() itself.

Specifically, this came up as a result of hackbench livelock'ing in
slab_lock() on ARC with SMP + SLUB + !LLSC.

The issue was incorrect pairing of atomic ops.

 slab_lock() -> bit_spin_lock() -> test_and_set_bit()
 slab_unlock() -> __bit_spin_unlock() -> __clear_bit()

The non serializing __clear_bit() was getting "lost"

 80543b8e:	ld_s       r2,[r13,0] <--- (A) Finds PG_locked is set
 80543b90:	or         r3,r2,1    <--- (B) other core unlocks right here
 80543b94:	st_s       r3,[r13,0] <--- (C) sets PG_locked (overwrites unlock)

Fixes ARC STAR 9000817404 (and probably more).

Reported-by: Vineet Gupta 
Tested-by: Vineet Gupta 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Andrew Morton 
Cc: Christoph Lameter 
Cc: David Rientjes 
Cc: Helge Deller 
Cc: James E.J. Bottomley 
Cc: Joonsoo Kim 
Cc: Linus Torvalds 
Cc: Noam Camus 
Cc: Paul E. McKenney 
Cc: Pekka Enberg 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20160309114054.GJ6356@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar 
Signed-off-by: Ben Hutchings

cputime: Prevent 32bit overflow in time[val|spec]_to_cputime()

2016-02-25T00:18:42+00:00

commit 0f26922fe5dc5724b1adbbd54b21bad03590b4f3 upstream.

The datatype __kernel_time_t is u32 on 32bit platform, so its subject to
overflows in the timeval/timespec to cputime conversion.

Currently the following functions are affected:
1. setitimer()
2. timer_create/timer_settime()
3. sys_clock_nanosleep

This can happen on MIPS32 and ARM32 with "Full dynticks CPU time accounting"
enabled, which is required for CONFIG_NO_HZ_FULL.

Enforce u64 conversion to prevent the overflow.

Fixes: 31c1fc818715 ("ARM: Kconfig: allow full nohz CPU accounting")
Signed-off-by: zengtao 
Reviewed-by: Arnd Bergmann 
Cc: 
Link: http://lkml.kernel.org/r/1454384314-154784-1-git-send-email-prime.zeng@huawei.com
Signed-off-by: Thomas Gleixner 
Signed-off-by: Luis Henriques

sched/preempt: Fix cond_resched_lock() and cond_resched_softirq()

2015-11-16T11:27:24+00:00

commit fe32d3cd5e8eb0f82e459763374aa80797023403 upstream.

These functions check should_resched() before unlocking spinlock/bh-enable:
preempt_count always non-zero => should_resched() always returns false.
cond_resched_lock() worked iff spin_needbreak is set.

This patch adds argument "preempt_offset" to should_resched().

preempt_count offset constants for that:

  PREEMPT_DISABLE_OFFSET  - offset after preempt_disable()
  PREEMPT_LOCK_OFFSET     - offset after spin_lock()
  SOFTIRQ_DISABLE_OFFSET  - offset after local_bh_distable()
  SOFTIRQ_LOCK_OFFSET     - offset after spin_lock_bh()

Signed-off-by: Konstantin Khlebnikov 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Alexander Graf 
Cc: Boris Ostrovsky 
Cc: David Vrabel 
Cc: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Fixes: bdb438065890 ("sched: Extract the basic add/sub preempt_count modifiers")
Link: http://lkml.kernel.org/r/20150715095204.12246.98268.stgit@buzz
Signed-off-by: Ingo Molnar 
[ luis: backported to 3.16:
  - some of the changes done in preempt_mask.h instead of preempt.h
  - adjusted context ]
Signed-off-by: Luis Henriques

nosave: consolidate __nosave_{begin,end} in

2015-05-06T09:24:18+00:00

commit 7f8998c7aef3ac9c5f3f2943e083dfa6302e90d0 upstream.

The different architectures used their own (and different) declarations:

    extern __visible const void __nosave_begin, __nosave_end;
    extern const void __nosave_begin, __nosave_end;
    extern long __nosave_begin, __nosave_end;

Consolidate them using the first variant in .

Signed-off-by: Geert Uytterhoeven 
Cc: Russell King 
Cc: Ralf Baechle 
Cc: Benjamin Herrenschmidt 
Cc: Martin Schwidefsky 
Cc: "David S. Miller" 
Cc: Guan Xuetao 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: "H. Peter Anvin" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Luis Henriques

core: fix typo in percpu read_mostly section

2014-07-01T20:45:22+00:00

This fixes a typo that named the read_mostly section of percpu as
readmostly. It works fine with SMP because the linker script specifies
.data..percpu..readmostly. However, UP kernel builds don't have percpu
sections defined and the non-percpu version of the section is called
data..read_mostly, so .data..readmostly will float around and may break
things unexpectedly.

Looking at the original change that introduced data..percpu..readmostly
(commit c957ef2c59e952803766ddc22e89981ab534606f), it looks like this
was the original intention.

Tested: Built UP kernel and confirmed the sections got merged.

- Before the patch:
$ objdump -h vmlinux.o  | grep '\.data\.\.read.*mostly'
38 .data..read_mostly 00004418  0000000000000000  0000000000000000  00431ac0  2**6
50 .data..readmostly 00000014  0000000000000000  0000000000000000  00444000  2**3

- After the patch:
$ objdump -h vmlinux.o  | grep '\.data\.\.read.*mostly'
38 .data..read_mostly 00004438  0000000000000000  0000000000000000  00431ac0  2**6

Signed-off-by: Zhengyu He 
Signed-off-by: Filipe Brandenburger 
Signed-off-by: Tejun Heo