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: 31c1fc8187 ("ARM: Kconfig: allow full nohz CPU accounting")
Signed-off-by: zengtao <prime.zeng@huawei.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Cc: <fweisbec@gmail.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1454384314-154784-1-git-send-email-prime.zeng@huawei.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Merge third patch-bomb from Andrew Morton:
"I'm pretty much done for -rc1 now:
- the rest of MM, basically
- lib/ updates
- checkpatch, epoll, hfs, fatfs, ptrace, coredump, exit
- cpu_mask simplifications
- kexec, rapidio, MAINTAINERS etc, etc.
- more dma-mapping cleanups/simplifications from hch"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (109 commits)
MAINTAINERS: add/fix git URLs for various subsystems
mm: memcontrol: add "sock" to cgroup2 memory.stat
mm: memcontrol: basic memory statistics in cgroup2 memory controller
mm: memcontrol: do not uncharge old page in page cache replacement
Documentation: cgroup: add memory.swap.{current,max} description
mm: free swap cache aggressively if memcg swap is full
mm: vmscan: do not scan anon pages if memcg swap limit is hit
swap.h: move memcg related stuff to the end of the file
mm: memcontrol: replace mem_cgroup_lruvec_online with mem_cgroup_online
mm: vmscan: pass memcg to get_scan_count()
mm: memcontrol: charge swap to cgroup2
mm: memcontrol: clean up alloc, online, offline, free functions
mm: memcontrol: flatten struct cg_proto
mm: memcontrol: rein in the CONFIG space madness
net: drop tcp_memcontrol.c
mm: memcontrol: introduce CONFIG_MEMCG_LEGACY_KMEM
mm: memcontrol: allow to disable kmem accounting for cgroup2
mm: memcontrol: account "kmem" consumers in cgroup2 memory controller
mm: memcontrol: move kmem accounting code to CONFIG_MEMCG
mm: memcontrol: separate kmem code from legacy tcp accounting code
...
The asm-generic tree this time contains one series from Nicolas Pitre
that makes the optimized do_div() implementation from the ARM
architecture available to all architectures. This also adds stricter
type checking for callers of do_div, which has uncovered a number
of bugs in existing code, and fixes up the ones we have found.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1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=4psa
-----END PGP SIGNATURE-----
Merge tag 'asm-generic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic
Pull asm-generic updates from Arnd Bergmann:
"The asm-generic tree this time contains one series from Nicolas Pitre
that makes the optimized do_div() implementation from the ARM
architecture available to all architectures.
This also adds stricter type checking for callers of do_div, which has
uncovered a number of bugs in existing code, and fixes up the ones we
have found"
* tag 'asm-generic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
ARM: asm/div64.h: adjust to generic codde
__div64_32(): make it overridable at compile time
__div64_const32(): abstract out the actual 128-bit cross product code
do_div(): generic optimization for constant divisor on 32-bit machines
div64.h: optimize do_div() for power-of-two constant divisors
mtd/sm_ftl.c: fix wrong do_div() usage
drm/mgag200/mgag200_mode.c: fix wrong do_div() usage
hid-sensor-hub.c: fix wrong do_div() usage
ti/fapll: fix wrong do_div() usage
ti/clkt_dpll: fix wrong do_div() usage
tegra/clk-divider: fix wrong do_div() usage
imx/clk-pllv2: fix wrong do_div() usage
imx/clk-pllv1: fix wrong do_div() usage
nouveau/nvkm/subdev/clk/gk20a.c: fix wrong do_div() usage
Move the generic implementation to <linux/dma-mapping.h> now that all
architectures support it and remove the HAVE_DMA_ATTR Kconfig symbol now
that everyone supports them.
[valentinrothberg@gmail.com: remove leftovers in Kconfig]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Helge Deller <deller@gmx.de>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Steven Miao <realmz6@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Valentin Rothberg <valentinrothberg@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This adds a new kind of barrier, and reworks virtio and xen
to use it.
Plus some fixes here and there.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1
iQEcBAABAgAGBQJWlU2kAAoJECgfDbjSjVRpZ6IH/Ra19ecG8sCQo9zskr4zo22Z
DZXC3u0sJDBYjjBAiw3IY1FKh7wx2Fr1RhUOj1bteBgcFCMCV1zInP5ITiCyzd1H
YYh1w9C2tZaj2T4t9L4hIrAdtIF8fGS+oI2IojXPjOuDLEt6pfFBEjHp/sfl3UJq
ZmZvw4OXviSNej7jBw8Xni3Uv18yfmLGXvMdkvMSPC1/XL29voGDqTVwhqJwxLVz
k/ZLcKFOzIs9N7Nja0Jl1EiZtC2Y9cpItqweicNAzszlpkSL44vQxmCSefB+WyQ4
gt0O3+AxYkLfrxzCBhUA4IpRex3/XPW1b+1e/V1XjfR2n/FlyLe+AIa8uPJElFc=
=ukaV
-----END PGP SIGNATURE-----
Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
Pull virtio barrier rework+fixes from Michael Tsirkin:
"This adds a new kind of barrier, and reworks virtio and xen to use it.
Plus some fixes here and there"
* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: (44 commits)
checkpatch: add virt barriers
checkpatch: check for __smp outside barrier.h
checkpatch.pl: add missing memory barriers
virtio: make find_vqs() checkpatch.pl-friendly
virtio_balloon: fix race between migration and ballooning
virtio_balloon: fix race by fill and leak
s390: more efficient smp barriers
s390: use generic memory barriers
xen/events: use virt_xxx barriers
xen/io: use virt_xxx barriers
xenbus: use virt_xxx barriers
virtio_ring: use virt_store_mb
sh: move xchg_cmpxchg to a header by itself
sh: support 1 and 2 byte xchg
virtio_ring: update weak barriers to use virt_xxx
Revert "virtio_ring: Update weak barriers to use dma_wmb/rmb"
asm-generic: implement virt_xxx memory barriers
x86: define __smp_xxx
xtensa: define __smp_xxx
tile: define __smp_xxx
...
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 <treding@nvidia.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Similar to the conversion of vm_insert_mixed() use pfn_t in the
vmf_insert_pfn_pmd() to tag the resulting pte with _PAGE_DEVICE when the
pfn is backed by a devm_memremap_pages() mapping.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
__phys_to_pfn and __pfn_to_phys are symmetric, PHYS_PFN and PFN_PHYS are
semmetric:
- y = (phys_addr_t)x << PAGE_SHIFT
- y >> PAGE_SHIFT = (phys_add_t)x
- (unsigned long)(y >> PAGE_SHIFT) = x
[akpm@linux-foundation.org: use macro arg name `x']
[arnd@arndb.de: include linux/pfn.h for PHYS_PFN definition]
Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Guests running within virtual machines might be affected by SMP effects even if
the guest itself is compiled without SMP support. This is an artifact of
interfacing with an SMP host while running an UP kernel. Using mandatory
barriers for this use-case would be possible but is often suboptimal.
In particular, virtio uses a bunch of confusing ifdefs to work around
this, while xen just uses the mandatory barriers.
To better handle this case, low-level virt_mb() etc macros are made available.
These are implemented trivially using the low-level __smp_xxx macros,
the purpose of these wrappers is to annotate those specific cases.
These have the same effect as smp_mb() etc when SMP is enabled, but generate
identical code for SMP and non-SMP systems. For example, virtual machine guests
should use virt_mb() rather than smp_mb() when synchronizing against a
(possibly SMP) host.
Suggested-by: David Miller <davem@davemloft.net>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
On !SMP, most architectures define their
barriers as compiler barriers.
On SMP, most need an actual barrier.
Make it possible to remove the code duplication for
!SMP by defining low-level __smp_xxx barriers
which do not depend on the value of SMP, then
use them from asm-generic conditionally.
Besides reducing code duplication, these low level APIs will also be
useful for virtualization, where a barrier is sometimes needed even if
!SMP since we might be talking to another kernel on the same SMP system.
Both virtio and Xen drivers will benefit.
The smp_xxx variants should use __smp_XXX ones or barrier() depending on
SMP, identically for all architectures.
We keep ifndef guards around them for now - once/if all
architectures are converted to use the generic
code, we'll be able to remove these.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Allow architectures to override smp_store_release
and smp_load_acquire by guarding the defines
in asm-generic/barrier.h with ifndef directives.
This is in preparation to reusing asm-generic/barrier.h
on architectures which have their own definition
of these macros.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
With commit b92b8b35a2 ("locking/arch: Rename set_mb() to smp_store_mb()")
it was made clear that the context of this call (and thus set_mb)
is strictly for CPU ordering, as opposed to IO. As such all archs
should use the smp variant of mb(), respecting the semantics and
saving a mandatory barrier on UP.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <linux-arch@vger.kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: dave@stgolabs.net
Link: http://lkml.kernel.org/r/1445975631-17047-3-git-send-email-dave@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Pull x86 mm updates from Ingo Molnar:
"The main changes in this cycle were:
- make the debugfs 'kernel_page_tables' file read-only, as it only
has read ops. (Borislav Petkov)
- micro-optimize clflush_cache_range() (Chris Wilson)
- swiotlb enhancements, which fixes certain KVM emulated devices
(Igor Mammedov)
- fix an LDT related debug message (Jan Beulich)
- modularize CONFIG_X86_PTDUMP (Kees Cook)
- tone down an overly alarming warning (Laura Abbott)
- Mark variable __initdata (Rasmus Villemoes)
- PAT additions (Toshi Kani)"
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm: Micro-optimise clflush_cache_range()
x86/mm/pat: Change free_memtype() to support shrinking case
x86/mm/pat: Add untrack_pfn_moved for mremap
x86/mm: Drop WARN from multi-BAR check
x86/LDT: Print the real LDT base address
x86/mm/64: Enable SWIOTLB if system has SRAT memory regions above MAX_DMA32_PFN
x86/mm: Introduce max_possible_pfn
x86/mm/ptdump: Make (debugfs)/kernel_page_tables read-only
x86/mm/mtrr: Mark the 'range_new' static variable in mtrr_calc_range_state() as __initdata
x86/mm: Turn CONFIG_X86_PTDUMP into a module
Pull locking updates from Ingo Molnar:
"So we have a laundry list of locking subsystem changes:
- continuing barrier API and code improvements
- futex enhancements
- atomics API improvements
- pvqspinlock enhancements: in particular lock stealing and adaptive
spinning
- qspinlock micro-enhancements"
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
futex: Allow FUTEX_CLOCK_REALTIME with FUTEX_WAIT op
futex: Cleanup the goto confusion in requeue_pi()
futex: Remove pointless put_pi_state calls in requeue()
futex: Document pi_state refcounting in requeue code
futex: Rename free_pi_state() to put_pi_state()
futex: Drop refcount if requeue_pi() acquired the rtmutex
locking/barriers, arch: Remove ambiguous statement in the smp_store_mb() documentation
lcoking/barriers, arch: Use smp barriers in smp_store_release()
locking/cmpxchg, arch: Remove tas() definitions
locking/pvqspinlock: Queue node adaptive spinning
locking/pvqspinlock: Allow limited lock stealing
locking/pvqspinlock: Collect slowpath lock statistics
sched/core, locking: Document Program-Order guarantees
locking, sched: Introduce smp_cond_acquire() and use it
locking/pvqspinlock, x86: Optimize the PV unlock code path
locking/qspinlock: Avoid redundant read of next pointer
locking/qspinlock: Prefetch the next node cacheline
locking/qspinlock: Use _acquire/_release() versions of cmpxchg() & xchg()
atomics: Add test for atomic operations with _relaxed variants
mremap() with MREMAP_FIXED on a VM_PFNMAP range causes the following
WARN_ON_ONCE() message in untrack_pfn().
WARNING: CPU: 1 PID: 3493 at arch/x86/mm/pat.c:985 untrack_pfn+0xbd/0xd0()
Call Trace:
[<ffffffff817729ea>] dump_stack+0x45/0x57
[<ffffffff8109e4b6>] warn_slowpath_common+0x86/0xc0
[<ffffffff8109e5ea>] warn_slowpath_null+0x1a/0x20
[<ffffffff8106a88d>] untrack_pfn+0xbd/0xd0
[<ffffffff811d2d5e>] unmap_single_vma+0x80e/0x860
[<ffffffff811d3725>] unmap_vmas+0x55/0xb0
[<ffffffff811d916c>] unmap_region+0xac/0x120
[<ffffffff811db86a>] do_munmap+0x28a/0x460
[<ffffffff811dec33>] move_vma+0x1b3/0x2e0
[<ffffffff811df113>] SyS_mremap+0x3b3/0x510
[<ffffffff817793ee>] entry_SYSCALL_64_fastpath+0x12/0x71
MREMAP_FIXED moves a pfnmap from old vma to new vma. untrack_pfn() is
called with the old vma after its pfnmap page table has been removed,
which causes follow_phys() to fail. The new vma has a new pfnmap to
the same pfn & cache type with VM_PAT set. Therefore, we only need to
clear VM_PAT from the old vma in this case.
Add untrack_pfn_moved(), which clears VM_PAT from a given old vma.
move_vma() is changed to call this function with the old vma when
VM_PFNMAP is set. move_vma() then calls do_munmap(), and untrack_pfn()
is a no-op since VM_PAT is cleared.
Reported-by: Stas Sergeev <stsp@list.ru>
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/1450832064-10093-2-git-send-email-toshi.kani@hpe.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
With commit b92b8b35a2 ("locking/arch: Rename set_mb() to smp_store_mb()")
it was made clear that the context of this call (and thus set_mb)
is strictly for CPU ordering, as opposed to IO. As such all archs
should use the smp variant of mb(), respecting the semantics and
saving a mandatory barrier on UP.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <linux-arch@vger.kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: dave@stgolabs.net
Link: http://lkml.kernel.org/r/1445975631-17047-3-git-send-email-dave@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This patch replaces the cmpxchg() and xchg() calls in the native
qspinlock code with the more relaxed _acquire or _release versions of
those calls to enable other architectures to adopt queued spinlocks
with less memory barrier performance overhead.
Signed-off-by: Waiman Long <Waiman.Long@hpe.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Douglas Hatch <doug.hatch@hpe.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Scott J Norton <scott.norton@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1447114167-47185-2-git-send-email-Waiman.Long@hpe.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There were still a number of references to my old Red Hat email
address in the kernel source. Remove these while keeping the
Red Hat copyright notices intact.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Some architectures may want to override the default implementation
at compile time to do things inline. For example, ARM uses a
non-standard calling convention for better efficiency in this case.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
The default C implementation for the 128-bit cross product is abstracted
into the __arch_xprod_64() macro that can be overridden to let
architectures provide their own assembly optimized implementation.
There are many advantages to an assembly version for this operation.
Carry bit handling becomes trivial, and 32-bit shifts may be achieved
simply by inverting register pairs on some architectures. This has the
potential to be quite faster and use much fewer instructions.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
64-by-32-bit divisions are prominent in the kernel, even on 32-bit
machines. Luckily, many of them use a constant divisor that allows
for a much faster multiplication by the divisor's reciprocal.
The compiler already performs this optimization when compiling a 32-by-32
division with a constant divisor. Unfortunately, on 32-bit machines, gcc
does not optimize 64-by-32 divisions in that case, except for constant
divisors that happen to be a power of 2.
Let's avoid the slow path whenever the divisor is constant by manually
computing the reciprocal ourselves and performing the multiplication
inline. In most cases, this improves performance of 64-by-32 divisions
by about two orders of magnitude compared to the __div64_32() fallback,
especially on architectures lacking a native div instruction.
The algorithm used here comes from the existing ARM code.
The __div64_const32_is_OK macro can be predefined by architectures to
disable this optimization in some cases. For example, some ancient gcc
version on ARM would crash with an ICE when fed this code.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Alexey Brodkin <abrodkin@synopsys.com>
Let's perform the obvious mask and shift operation in this case.
On 32-bit targets, gcc is able to do the same thing with a constant
divisor that happens to be a power of two i.e. it turns the division
into an inline shift, but it doesn't hurt to be explicit.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
The asm-generic changes for 4.4 are mostly a series from Christoph Hellwig
to clean up various abuses of headers in there. The patch to rename the
io-64-nonatomic-*.h headers caused some conflicts with new users, so I
added a workaround that we can remove in the next merge window.
The only other patch is a warning fix from Marek Vasut
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1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=dQKG
-----END PGP SIGNATURE-----
Merge tag 'asm-generic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic
Pull asm-generic cleanups from Arnd Bergmann:
"The asm-generic changes for 4.4 are mostly a series from Christoph
Hellwig to clean up various abuses of headers in there. The patch to
rename the io-64-nonatomic-*.h headers caused some conflicts with new
users, so I added a workaround that we can remove in the next merge
window.
The only other patch is a warning fix from Marek Vasut"
* tag 'asm-generic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
asm-generic: temporarily add back asm-generic/io-64-nonatomic*.h
asm-generic: cmpxchg: avoid warnings from macro-ized cmpxchg() implementations
gpio-mxc: stop including <asm-generic/bug>
n_tracesink: stop including <asm-generic/bug>
n_tracerouter: stop including <asm-generic/bug>
mlx5: stop including <asm-generic/kmap_types.h>
hifn_795x: stop including <asm-generic/kmap_types.h>
drbd: stop including <asm-generic/kmap_types.h>
move count_zeroes.h out of asm-generic
move io-64-nonatomic*.h out of asm-generic
- ACPICA update to upstream revision 20150930 (Bob Moore, Lv Zheng).
The most significant change is to allow the AML debugger to be
built into the kernel. On top of that there is an update related
to the NFIT table (the ACPI persistent memory interface)
and a few fixes and cleanups.
- ACPI CPPC2 (Collaborative Processor Performance Control v2)
support along with a cpufreq frontend (Ashwin Chaugule).
This can only be enabled on ARM64 at this point.
- New ACPI infrastructure for the early probing of IRQ chips and
clock sources (Marc Zyngier).
- Support for a new hierarchical properties extension of the ACPI
_DSD (Device Specific Data) device configuration object allowing
the kernel to handle hierarchical properties (provided by the
platform firmware this way) automatically and make them available
to device drivers via the generic device properties interface
(Rafael Wysocki).
- Generic device properties API extension to obtain an index of
certain string value in an array of strings, along the lines of
of_property_match_string(), but working for all of the supported
firmware node types, and support for the "dma-names" device
property based on it (Mika Westerberg).
- ACPI core fix to parse the MADT (Multiple APIC Description Table)
entries in the order expected by platform firmware (and mandated
by the specification) to avoid confusion on systems with more than
255 logical CPUs (Lukasz Anaczkowski).
- Consolidation of the ACPI-based handling of PCI host bridges
on x86 and ia64 (Jiang Liu).
- ACPI core fixes to ensure that the correct IRQ number is used to
represent the SCI (System Control Interrupt) in the cases when
it has been re-mapped (Chen Yu).
- New ACPI backlight quirk for Lenovo IdeaPad S405 (Hans de Goede).
- ACPI EC driver fixes (Lv Zheng).
- Assorted ACPI fixes and cleanups (Dan Carpenter, Insu Yun, Jiri
Kosina, Rami Rosen, Rasmus Villemoes).
- New mechanism in the PM core allowing drivers to check if the
platform firmware is going to be involved in the upcoming system
suspend or if it has been involved in the suspend the system is
resuming from at the moment (Rafael Wysocki).
This should allow drivers to optimize their suspend/resume
handling in some cases and the changes include a couple of users
of it (the i8042 input driver, PCI PM).
- PCI PM fix to prevent runtime-suspended devices with PME enabled
from being resumed during system suspend even if they aren't
configured to wake up the system from sleep (Rafael Wysocki).
- New mechanism to report the number of a wakeup IRQ that woke up
the system from sleep last time (Alexandra Yates).
- Removal of unused interfaces from the generic power domains
framework and fixes related to latency measurements in that
code (Ulf Hansson, Daniel Lezcano).
- cpufreq core sysfs interface rework to make it handle CPUs that
share performance scaling settings (represented by a common
cpufreq policy object) more symmetrically (Viresh Kumar).
This should help to simplify the CPU offline/online handling among
other things.
- cpufreq core fixes and cleanups (Viresh Kumar).
- intel_pstate fixes related to the Turbo Activation Ratio (TAR)
mechanism on client platforms which causes the turbo P-states
range to vary depending on platform firmware settings (Srinivas
Pandruvada).
- intel_pstate sysfs interface fix (Prarit Bhargava).
- Assorted cpufreq driver (imx, tegra20, powernv, integrator) fixes
and cleanups (Bai Ping, Bartlomiej Zolnierkiewicz, Shilpasri G
Bhat, Luis de Bethencourt).
- cpuidle mvebu driver cleanups (Russell King).
- OPP (Operating Performance Points) framework code reorganization
to make it more maintainable (Viresh Kumar).
- Intel Broxton support for the RAPL (Running Average Power Limits)
power capping driver (Amy Wiles).
- Assorted power management code fixes and cleanups (Dan Carpenter,
Geert Uytterhoeven, Geliang Tang, Luis de Bethencourt, Rasmus
Villemoes).
/
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.22 (GNU/Linux)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=1gaH
-----END PGP SIGNATURE-----
Merge tag 'pm+acpi-4.4-rc1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management and ACPI updates from Rafael Wysocki:
"Quite a new features are included this time.
First off, the Collaborative Processor Performance Control interface
(version 2) defined by ACPI will now be supported on ARM64 along with
a cpufreq frontend for CPU performance scaling.
Second, ACPI gets a new infrastructure for the early probing of IRQ
chips and clock sources (along the lines of the existing similar
mechanism for DT).
Next, the ACPI core and the generic device properties API will now
support a recently introduced hierarchical properties extension of the
_DSD (Device Specific Data) ACPI device configuration object. If the
ACPI platform firmware uses that extension to organize device
properties in a hierarchical way, the kernel will automatically handle
it and make those properties available to device drivers via the
generic device properties API.
It also will be possible to build the ACPICA's AML interpreter
debugger into the kernel now and use that to diagnose AML-related
problems more efficiently. In the future, this should make it
possible to single-step AML execution and do similar things.
Interesting stuff, although somewhat experimental at this point.
Finally, the PM core gets a new mechanism that can be used by device
drivers to distinguish between suspend-to-RAM (based on platform
firmware support) and suspend-to-idle (or other variants of system
suspend the platform firmware is not involved in) and possibly
optimize their device suspend/resume handling accordingly.
In addition to that, some existing features are re-organized quite
substantially.
First, the ACPI-based handling of PCI host bridges on x86 and ia64 is
unified and the common code goes into the ACPI core (so as to reduce
code duplication and eliminate non-essential differences between the
two architectures in that area).
Second, the Operating Performance Points (OPP) framework is
reorganized to make the code easier to find and follow.
Next, the cpufreq core's sysfs interface is reorganized to get rid of
the "primary CPU" concept for configurations in which the same
performance scaling settings are shared between multiple CPUs.
Finally, some interfaces that aren't necessary any more are dropped
from the generic power domains framework.
On top of the above we have some minor extensions, cleanups and bug
fixes in multiple places, as usual.
Specifics:
- ACPICA update to upstream revision 20150930 (Bob Moore, Lv Zheng).
The most significant change is to allow the AML debugger to be
built into the kernel. On top of that there is an update related
to the NFIT table (the ACPI persistent memory interface) and a few
fixes and cleanups.
- ACPI CPPC2 (Collaborative Processor Performance Control v2) support
along with a cpufreq frontend (Ashwin Chaugule).
This can only be enabled on ARM64 at this point.
- New ACPI infrastructure for the early probing of IRQ chips and
clock sources (Marc Zyngier).
- Support for a new hierarchical properties extension of the ACPI
_DSD (Device Specific Data) device configuration object allowing
the kernel to handle hierarchical properties (provided by the
platform firmware this way) automatically and make them available
to device drivers via the generic device properties interface
(Rafael Wysocki).
- Generic device properties API extension to obtain an index of
certain string value in an array of strings, along the lines of
of_property_match_string(), but working for all of the supported
firmware node types, and support for the "dma-names" device
property based on it (Mika Westerberg).
- ACPI core fix to parse the MADT (Multiple APIC Description Table)
entries in the order expected by platform firmware (and mandated by
the specification) to avoid confusion on systems with more than 255
logical CPUs (Lukasz Anaczkowski).
- Consolidation of the ACPI-based handling of PCI host bridges on x86
and ia64 (Jiang Liu).
- ACPI core fixes to ensure that the correct IRQ number is used to
represent the SCI (System Control Interrupt) in the cases when it
has been re-mapped (Chen Yu).
- New ACPI backlight quirk for Lenovo IdeaPad S405 (Hans de Goede).
- ACPI EC driver fixes (Lv Zheng).
- Assorted ACPI fixes and cleanups (Dan Carpenter, Insu Yun, Jiri
Kosina, Rami Rosen, Rasmus Villemoes).
- New mechanism in the PM core allowing drivers to check if the
platform firmware is going to be involved in the upcoming system
suspend or if it has been involved in the suspend the system is
resuming from at the moment (Rafael Wysocki).
This should allow drivers to optimize their suspend/resume handling
in some cases and the changes include a couple of users of it (the
i8042 input driver, PCI PM).
- PCI PM fix to prevent runtime-suspended devices with PME enabled
from being resumed during system suspend even if they aren't
configured to wake up the system from sleep (Rafael Wysocki).
- New mechanism to report the number of a wakeup IRQ that woke up the
system from sleep last time (Alexandra Yates).
- Removal of unused interfaces from the generic power domains
framework and fixes related to latency measurements in that code
(Ulf Hansson, Daniel Lezcano).
- cpufreq core sysfs interface rework to make it handle CPUs that
share performance scaling settings (represented by a common cpufreq
policy object) more symmetrically (Viresh Kumar).
This should help to simplify the CPU offline/online handling among
other things.
- cpufreq core fixes and cleanups (Viresh Kumar).
- intel_pstate fixes related to the Turbo Activation Ratio (TAR)
mechanism on client platforms which causes the turbo P-states range
to vary depending on platform firmware settings (Srinivas
Pandruvada).
- intel_pstate sysfs interface fix (Prarit Bhargava).
- Assorted cpufreq driver (imx, tegra20, powernv, integrator) fixes
and cleanups (Bai Ping, Bartlomiej Zolnierkiewicz, Shilpasri G
Bhat, Luis de Bethencourt).
- cpuidle mvebu driver cleanups (Russell King).
- OPP (Operating Performance Points) framework code reorganization to
make it more maintainable (Viresh Kumar).
- Intel Broxton support for the RAPL (Running Average Power Limits)
power capping driver (Amy Wiles).
- Assorted power management code fixes and cleanups (Dan Carpenter,
Geert Uytterhoeven, Geliang Tang, Luis de Bethencourt, Rasmus
Villemoes)"
* tag 'pm+acpi-4.4-rc1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (108 commits)
cpufreq: postfix policy directory with the first CPU in related_cpus
cpufreq: create cpu/cpufreq/policyX directories
cpufreq: remove cpufreq_sysfs_{create|remove}_file()
cpufreq: create cpu/cpufreq at boot time
cpufreq: Use cpumask_copy instead of cpumask_or to copy a mask
cpufreq: ondemand: Drop unnecessary locks from update_sampling_rate()
PM / Domains: Merge measurements for PM QoS device latencies
PM / Domains: Don't measure ->start|stop() latency in system PM callbacks
PM / clk: Fix broken build due to non-matching code and header #ifdefs
ACPI / Documentation: add copy_dsdt to ACPI format options
ACPI / sysfs: correctly check failing memory allocation
ACPI / video: Add a quirk to force native backlight on Lenovo IdeaPad S405
ACPI / CPPC: Fix potential memory leak
ACPI / CPPC: signedness bug in register_pcc_channel()
ACPI / PAD: power_saving_thread() is not freezable
ACPI / PM: Fix incorrect wakeup IRQ setting during suspend-to-idle
ACPI: Using correct irq when waiting for events
ACPI: Use correct IRQ when uninstalling ACPI interrupt handler
cpuidle: mvebu: disable the bind/unbind attributes and use builtin_platform_driver
cpuidle: mvebu: clean up multiple platform drivers
...
Pull s390 updates from Martin Schwidefsky:
"There is only one new feature in this pull for the 4.4 merge window,
most of it is small enhancements, cleanup and bug fixes:
- Add the s390 backend for the software dirty bit tracking. This
adds two new pgtable functions pte_clear_soft_dirty and
pmd_clear_soft_dirty which is why there is a hit to
arch/x86/include/asm/pgtable.h in this pull request.
- A series of cleanup patches for the AP bus, this includes the
removal of the support for two outdated crypto cards (PCICC and
PCICA).
- The irq handling / signaling on buffer full in the runtime
instrumentation code is dropped.
- Some micro optimizations: remove unnecessary memory barriers for a
couple of functions: [smb_]rmb, [smb_]wmb, atomics, bitops, and for
spin_unlock. Use the builtin bswap if available and make
test_and_set_bit_lock more cache friendly.
- Statistics and a tracepoint for the diagnose calls to the
hypervisor.
- The CPU measurement facility support to sample KVM guests is
improved.
- The vector instructions are now always enabled for user space
processes if the hardware has the vector facility. This simplifies
the FPU handling code. The fpu-internal.h header is split into fpu
internals, api and types just like x86.
- Cleanup and improvements for the common I/O layer.
- Rework udelay to solve a problem with kprobe. udelay has busy loop
semantics but still uses an idle processor state for the wait"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (66 commits)
s390: remove runtime instrumentation interrupts
s390/cio: de-duplicate subchannel validation
s390/css: unneeded initialization in for_each_subchannel
s390/Kconfig: use builtin bswap
s390/dasd: fix disconnected device with valid path mask
s390/dasd: fix invalid PAV assignment after suspend/resume
s390/dasd: fix double free in dasd_eckd_read_conf
s390/kernel: fix ptrace peek/poke for floating point registers
s390/cio: move ccw_device_stlck functions
s390/cio: move ccw_device_call_handler
s390/topology: reduce per_cpu() invocations
s390/nmi: reduce size of percpu variable
s390/nmi: fix terminology
s390/nmi: remove casts
s390/nmi: remove pointless error strings
s390: don't store registers on disabled wait anymore
s390: get rid of __set_psw_mask()
s390/fpu: split fpu-internal.h into fpu internals, api, and type headers
s390/dasd: fix list_del corruption after lcu changes
s390/spinlock: remove unneeded serializations at unlock
...
Pull scheduler changes from Ingo Molnar:
"The main changes in this cycle were:
- sched/fair load tracking fixes and cleanups (Byungchul Park)
- Make load tracking frequency scale invariant (Dietmar Eggemann)
- sched/deadline updates (Juri Lelli)
- stop machine fixes, cleanups and enhancements for bugs triggered by
CPU hotplug stress testing (Oleg Nesterov)
- scheduler preemption code rework: remove PREEMPT_ACTIVE and related
cleanups (Peter Zijlstra)
- Rework the sched_info::run_delay code to fix races (Peter Zijlstra)
- Optimize per entity utilization tracking (Peter Zijlstra)
- ... misc other fixes, cleanups and smaller updates"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (57 commits)
sched: Don't scan all-offline ->cpus_allowed twice if !CONFIG_CPUSETS
sched: Move cpu_active() tests from stop_two_cpus() into migrate_swap_stop()
sched: Start stopper early
stop_machine: Kill cpu_stop_threads->setup() and cpu_stop_unpark()
stop_machine: Kill smp_hotplug_thread->pre_unpark, introduce stop_machine_unpark()
stop_machine: Change cpu_stop_queue_two_works() to rely on stopper->enabled
stop_machine: Introduce __cpu_stop_queue_work() and cpu_stop_queue_two_works()
stop_machine: Ensure that a queued callback will be called before cpu_stop_park()
sched/x86: Fix typo in __switch_to() comments
sched/core: Remove a parameter in the migrate_task_rq() function
sched/core: Drop unlikely behind BUG_ON()
sched/core: Fix task and run queue sched_info::run_delay inconsistencies
sched/numa: Fix task_tick_fair() from disabling numa_balancing
sched/core: Add preempt_count invariant check
sched/core: More notrace annotations
sched/core: Kill PREEMPT_ACTIVE
sched/core, sched/x86: Kill thread_info::saved_preempt_count
sched/core: Simplify preempt_count tests
sched/core: Robustify preemption leak checks
sched/core: Stop setting PREEMPT_ACTIVE
...
This seems to be a mis-reading of how alpha memory ordering works, and
is not backed up by the alpha architecture manual. The helper functions
don't do anything special on any other architectures, and the arguments
that support them being safe on other architectures also argue that they
are safe on alpha.
Basically, the "control dependency" is between a previous read and a
subsequent write that is dependent on the value read. Even if the
subsequent write is actually done speculatively, there is no way that
such a speculative write could be made visible to other cpu's until it
has been committed, which requires validating the speculation.
Note that most weakely ordered architectures (very much including alpha)
do not guarantee any ordering relationship between two loads that depend
on each other on a control dependency:
read A
if (val == 1)
read B
because the conditional may be predicted, and the "read B" may be
speculatively moved up to before reading the value A. So we require the
user to insert a smp_rmb() between the two accesses to be correct:
read A;
if (A == 1)
smp_rmb()
read B
Alpha is further special in that it can break that ordering even if the
*address* of B depends on the read of A, because the cacheline that is
read later may be stale unless you have a memory barrier in between the
pointer read and the read of the value behind a pointer:
read ptr
read offset(ptr)
whereas all other weakly ordered architectures guarantee that the data
dependency (as opposed to just a control dependency) will order the two
accesses. As a result, alpha needs a "smp_read_barrier_depends()" in
between those two reads for them to be ordered.
The coontrol dependency that "READ_ONCE_CTRL()" and "atomic_read_ctrl()"
had was a control dependency to a subsequent *write*, however, and
nobody can finalize such a subsequent write without having actually done
the read. And were you to write such a value to a "stale" cacheline
(the way the unordered reads came to be), that would seem to lose the
write entirely.
So the things that make alpha able to re-order reads even more
aggressively than other weak architectures do not seem to be relevant
for a subsequent write. Alpha memory ordering may be strange, but
there's no real indication that it is *that* strange.
Also, the alpha architecture reference manual very explicitly talks
about the definition of "Dependence Constraints" in section 5.6.1.7,
where a preceding read dominates a subsequent write.
Such a dependence constraint admittedly does not impose a BEFORE (alpha
architecture term for globally visible ordering), but it does guarantee
that there can be no "causal loop". I don't see how you could avoid
such a loop if another cpu could see the stored value and then impact
the value of the first read. Put another way: the read and the write
could not be seen as being out of order wrt other cpus.
So I do not see how these "x_ctrl()" functions can currently be necessary.
I may have to eat my words at some point, but in the absense of clear
proof that alpha actually needs this, or indeed even an explanation of
how alpha could _possibly_ need it, I do not believe these functions are
called for.
And if it turns out that alpha really _does_ need a barrier for this
case, that barrier still should not be "smp_read_barrier_depends()".
We'd have to make up some new speciality barrier just for alpha, along
with the documentation for why it really is necessary.
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul E McKenney <paulmck@us.ibm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull locking changes from Ingo Molnar:
"The main changes in this cycle were:
- More gradual enhancements to atomic ops: new atomic*_read_ctrl()
ops, synchronize atomic_{read,set}() ordering requirements between
architectures, add atomic_long_t bitops. (Peter Zijlstra)
- Add _{relaxed|acquire|release}() variants for inc/dec atomics and
use them in various locking primitives: mutex, rtmutex, mcs, rwsem.
This enables weakly ordered architectures (such as arm64) to make
use of more locking related optimizations. (Davidlohr Bueso)
- Implement atomic[64]_{inc,dec}_relaxed() on ARM. (Will Deacon)
- Futex kernel data cache footprint micro-optimization. (Rasmus
Villemoes)
- pvqspinlock runtime overhead micro-optimization. (Waiman Long)
- misc smaller fixlets"
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
ARM, locking/atomics: Implement _relaxed variants of atomic[64]_{inc,dec}
locking/rwsem: Use acquire/release semantics
locking/mcs: Use acquire/release semantics
locking/rtmutex: Use acquire/release semantics
locking/mutex: Use acquire/release semantics
locking/asm-generic: Add _{relaxed|acquire|release}() variants for inc/dec atomics
atomic: Implement atomic_read_ctrl()
atomic, arch: Audit atomic_{read,set}()
atomic: Add atomic_long_t bitops
futex: Force hot variables into a single cache line
locking/pvqspinlock: Kick the PV CPU unconditionally when _Q_SLOW_VAL
locking/osq: Relax atomic semantics
locking/qrwlock: Rename ->lock to ->wait_lock
locking/Documentation/lockstat: Fix typo - lokcing -> locking
locking/atomics, cmpxchg: Privatize the inclusion of asm/cmpxchg.h
- pgtable-generic.c: Fold individual #ifdef for each helper into a top
level #ifdef. Makes code more readable
- Converted the stub helpers for !THP to BUILD_BUG() vs. runtime BUG()
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Link: http://lkml.kernel.org/r/20151009133450.GA8597@node
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
New users of these files still start showing up in linux-next, so it's
better to have a migration strategy. All existing users as of 4.3-rc4
are converted to use linux/io-64-nonatomic-*.h, and after 4.4-rc1
we can change all the new ones that have come in since, and then
remove this file again.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reported-by: LKP project <lkp@linux.intel.com>
This change is similar to e001bbae71
ARM: cmpxchg: avoid warnings from macro-ized cmpxchg() implementations
A recent change in kernel/acct.c added a new warning for many
configurations using generic __xchg() implementation:
In file included from ./arch/nios2/include/asm/cmpxchg.h:12:0,
from include/asm-generic/atomic.h:18,
from arch/nios2/include/generated/asm/atomic.h:1,
from include/linux/atomic.h:4,
from include/linux/spinlock.h:406,
from include/linux/mmzone.h:7,
from include/linux/gfp.h:5,
from include/linux/mm.h:9,
from kernel/acct.c:46:
kernel/acct.c: In function 'acct_pin_kill':
include/asm-generic/cmpxchg.h:94:3: warning: value computed is not used [-Wunused-value]
((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\
^
include/asm-generic/cmpxchg.h:102:28: note: in expansion of macro 'cmpxchg_local'
#define cmpxchg(ptr, o, n) cmpxchg_local((ptr), (o), (n))
^
kernel/acct.c:177:2: note: in expansion of macro 'cmpxchg'
cmpxchg(&acct->ns->bacct, pin, NULL);
^
The code is in fact correct, it's just a cmpxchg() call that
intentionally ignores the result, and no other code does that. The
warning does not show up on x86 because of the way that its cmpxchg()
macro is written. This changes the asm-ggeneric implementation to use
a similar construct with a compound expression instead of a typecast,
which causes the compiler to not complain about an unused result.
Fix the other macros in this file in a similar way, and place them
just below their function implementations.
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
This header contains a few helpers currenly only used by the mpi
implementation, and not default implementation of architecture code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
These are not implementations of default architecture code but helpers
for drivers. Move them to the place they belong to.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Darren Hart <dvhart@linux.intel.com>
Acked-by: Hitoshi Mitake <mitake.hitoshi@lab.ntt.co.jp>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
There are primitives to create and query the software dirty bits
in a pte or pmd. But the clearing of the software dirty bits is done
in common code with x86 specific page table functions.
Add the missing architecture primitives to clear the software dirty
bits to allow the feature to be used on non-x86 systems, e.g. the
s390 architecture.
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
As of 654672d4ba (locking/atomics: Add _{acquire|release|relaxed}()
variants of some atomic operations) and 6d79ef2d30 (locking, asm-generic:
Add _{relaxed|acquire|release}() variants for 'atomic_long_t'), weakly
ordered archs can benefit from more relaxed use of barriers when locking
and unlocking, instead of regular full barrier semantics. While currently
only arm64 supports such optimizations, updating corresponding locking
primitives serves for other archs to immediately benefit as well, once the
necessary machinery is implemented of course.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul E.McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/1443643395-17016-6-git-send-email-dave@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
As of 654672d4ba (locking/atomics: Add _{acquire|release|relaxed}()
variants of some atomic operations) and 6d79ef2d30 (locking, asm-generic:
Add _{relaxed|acquire|release}() variants for 'atomic_long_t'), weakly
ordered archs can benefit from more relaxed use of barriers when locking
and unlocking, instead of regular full barrier semantics. While currently
only arm64 supports such optimizations, updating corresponding locking
primitives serves for other archs to immediately benefit as well, once the
necessary machinery is implemented of course.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul E.McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/1443643395-17016-3-git-send-email-dave@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Similar to what we have for regular add/sub calls. For now, no actual arch
implements them, so everyone falls back to the default atomics... iow,
nothing changes. These will be used in future primitives.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul E.McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/1443643395-17016-2-git-send-email-dave@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Assuming units of PREEMPT_DISABLE_OFFSET for preempt_count() numbers.
Now that TASK_DEAD no longer results in preempt_count() == 3 during
scheduling, we will always call context_switch() with preempt_count()
== 2.
However, we don't always end up with preempt_count() == 2 in
finish_task_switch() because new tasks get created with
preempt_count() == 1.
Create FORK_PREEMPT_COUNT and set it to 2 and use that in the right
places. Note that we cannot use INIT_PREEMPT_COUNT as that serves
another purpose (boot).
After this, preempt_count() is invariant across the context switch,
with exception of PREEMPT_ACTIVE.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull strscpy string copy function implementation from Chris Metcalf.
Chris sent this during the merge window, but I waffled back and forth on
the pull request, which is why it's going in only now.
The new "strscpy()" function is definitely easier to use and more secure
than either strncpy() or strlcpy(), both of which are horrible nasty
interfaces that have serious and irredeemable problems.
strncpy() has a useless return value, and doesn't NUL-terminate an
overlong result. To make matters worse, it pads a short result with
zeroes, which is a performance disaster if you have big buffers.
strlcpy(), by contrast, is a mis-designed "fix" for strlcpy(), lacking
the insane NUL padding, but having a differently broken return value
which returns the original length of the source string. Which means
that it will read characters past the count from the source buffer, and
you have to trust the source to be properly terminated. It also makes
error handling fragile, since the test for overflow is unnecessarily
subtle.
strscpy() avoids both these problems, guaranteeing the NUL termination
(but not excessive padding) if the destination size wasn't zero, and
making the overflow condition very obvious by returning -E2BIG. It also
doesn't read past the size of the source, and can thus be used for
untrusted source data too.
So why did I waffle about this for so long?
Every time we introduce a new-and-improved interface, people start doing
these interminable series of trivial conversion patches.
And every time that happens, somebody does some silly mistake, and the
conversion patch to the improved interface actually makes things worse.
Because the patch is mindnumbing and trivial, nobody has the attention
span to look at it carefully, and it's usually done over large swatches
of source code which means that not every conversion gets tested.
So I'm pulling the strscpy() support because it *is* a better interface.
But I will refuse to pull mindless conversion patches. Use this in
places where it makes sense, but don't do trivial patches to fix things
that aren't actually known to be broken.
* 'strscpy' of git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
tile: use global strscpy() rather than private copy
string: provide strscpy()
Make asm/word-at-a-time.h available on all architectures
DT enjoys a rather nice probing infrastructure for clocksources,
while ACPI is so far stuck into a very distant past.
This patch introduces a declarative API, allowing clocksources
to be self-contained and be called when parsing the GTDT table.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
DT enjoys a rather nice probing infrastructure for irqchips, while
ACPI is so far stuck into a very distant past.
This patch introduces a declarative API, allowing irqchips to be
self-contained and be called when a particular entry is matched
in the MADT table.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
IRQ controllers and timers are the two types of device the kernel
requires before being able to use the device driver model.
ACPI so far lacks a proper probing infrastructure similar to the one
we have with DT, where we're able to declare IRQ chips and
clocksources inside the driver code, and let the core code pick it up
and call us back on a match. This leads to all kind of really ugly
hacks all over the arm64 code and even in the ACPI layer.
In order to allow some basic probing based on the ACPI tables,
introduce "struct acpi_probe_entry" which contains just enough
data and callbacks to match a table, an optional subtable, and
call a probe function. A driver can, at build time, register itself
and expect being called if the right entry exists in the ACPI
table.
A acpi_probe_device_table() is provided, taking an identifier for
a set of acpi_prove_entries, and iterating over the registered
entries.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Provide atomic_read_ctrl() to mirror READ_ONCE_CTRL(), such that we can
more conveniently use atomics in control dependencies.
Since we can assume atomic_read() implies a READ_ONCE(), we must only
emit an extra smp_read_barrier_depends() in order to upgrade to
READ_ONCE_CTRL() semantics.
Requested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Cc: oleg@redhat.com
Link: http://lkml.kernel.org/r/20150918115637.GM3604@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
