If a syscall is entered without TIF_SYSCALL_TRACE set, then it goes on
the fast path.  It's then possible to have TIF_SYSCALL_TRACE added in
the middle of the syscall, but ret_fast_syscall doesn't check this flag
again.  This causes a ptrace syscall-exit-stop to be missed.

For instance, from a PTRACE_EVENT_FORK reported during do_fork, the
tracer might resume with PTRACE_SYSCALL, setting TIF_SYSCALL_TRACE.
Now the completion of the fork should have a syscall-exit-stop.

Russell King fixed this on arm by re-checking _TIF_SYSCALL_WORK in the
fast exit path.  Do the same on arm64.
Reviewed-by: Will Deacon <will.deacon@arm.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Josh Stone <jistone@redhat.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

* 'arm64/psci-rework' of git://git.kernel.org/pub/scm/linux/kernel/git/mark/linux:
  arm64: psci: remove ACPI coupling
  arm64: psci: kill psci_power_state
  arm64: psci: account for Trusted OS instances
  arm64: psci: support unsigned return values
  arm64: psci: remove unnecessary id indirection
  arm64: smp: consistently use error codes
  arm64: smp_plat: add get_logical_index
  arm/arm64: kvm: add missing PSCI include

Conflicts:
	arch/arm64/kernel/smp.c

AArch64 toolchains suffer from the following bug:

$ cat blah.S
1:
	.inst	0x01020304
	.if ((. - 1b) != 4)
		.error	"blah"
	.endif
$ aarch64-linux-gnu-gcc -c blah.S
blah.S: Assembler messages:
blah.S:3: Error: non-constant expression in ".if" statement

which precludes the use of msr_s and co as part of alternatives.

We workaround this issue by not directly testing the labels
themselves, but by moving the current output pointer by a value
that should always be zero. If this value is not null, then
we will trigger a backward move, which is expclicitely forbidden.
This triggers the error we're after:

  AS      arch/arm64/kvm/hyp.o
arch/arm64/kvm/hyp.S: Assembler messages:
arch/arm64/kvm/hyp.S:1377: Error: attempt to move .org backwards
scripts/Makefile.build:294: recipe for target 'arch/arm64/kvm/hyp.o' failed
make[1]: *** [arch/arm64/kvm/hyp.o] Error 1
Makefile:946: recipe for target 'arch/arm64/kvm' failed

Not pretty, but at least works on the current toolchains.
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

asm/alternative-asm.h and asm/alternative.h are extremely similar,
and really deserve to live in the same file (as this makes further
modufications a bit easier).

Fold the content of alternative-asm.h into alternative.h, and
update the few users.
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Since all branches are PC-relative on AArch64, these instructions
cannot be used as an alternative with the simplistic approach
we currently have (the immediate has been computed from
the .altinstr_replacement section, and end-up being completely off
if the target is outside of the replacement sequence).

This patch handles the branch instructions in a different way,
using the insn framework to recompute the immediate, and generate
the right displacement in the above case.
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

The workaround for erratum 845719 is currently using
a branch between two alternate sequences, which is
quite fragile, and that we are going to break as we
rework the alternative code.

This patch reworks the workaround to fit in a single
alternative sequence. The generated code itself is
unchanged.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

In order to deal with branches located in alternate sequences,
but pointing to the main kernel text, it is required to extract
the relative displacement encoded in the instruction, and to be
able to update said instruction with a new offset (once it is
known).

For this, we introduce three new helpers:
- aarch64_insn_is_branch_imm is a predicate indicating if the
  instruction is an immediate branch
- aarch64_get_branch_offset returns a signed value representing
  the byte offset encoded in a branch instruction
- aarch64_set_branch_offset takes an instruction and an offset,
  and returns the corresponding updated instruction.
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Two cleanups of the asm function cpu_resume():
- The global variable sleep_idmap_phys always points to idmap_pg_dir,
  so we can just use that value directly in the CPU resume path.
- Unclutter the load of sleep_save_sp::save_ptr_stash_phys.
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Commit ea8c2e11 ("arm64: Extend the idmap to the whole kernel
image") changed the early page table code so that the entire kernel
Image is covered by the identity map. This allows functions that
need to enable or disable the MMU to reside anywhere in the kernel
Image.

However, this change has the unfortunate side effect that the Image
cannot cross a physical 512 MB alignment boundary anymore, since the
early page table code cannot deal with the Image crossing a /virtual/
512 MB alignment boundary.

So instead, reduce the ID map to a single page, that is populated by
the contents of the .idmap.text section. Only three functions reside
there at the moment: __enable_mmu(), cpu_resume_mmu() and cpu_reset().
If new code is introduced that needs to manipulate the MMU state, it
should be added to this section as well.
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Currently, the FDT blob needs to be in the same 512 MB region as
the kernel, so that it can be mapped into the kernel virtual memory
space very early on using a minimal set of statically allocated
translation tables.

Now that we have early fixmap support, we can relax this restriction,
by moving the permanent FDT mapping to the fixmap region instead.
This way, the FDT blob may be anywhere in memory.

This also moves the vetting of the FDT to mmu.c, since the early
init code in head.S does not handle mapping of the FDT anymore.
At the same time, fix up some comments in head.S that have gone stale.
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

This splits off the reservation of the memory occupied by the FDT
binary itself from the processing of the memory reservations it
contains. This is necessary because the physical address of the FDT,
which is needed to perform the reservation, may not be known to the
FDT driver core, i.e., it may be mapped outside the linear direct
mapping, in which case __pa() returns a bogus value.

Cc: Russell King <linux@arm.linux.org.uk>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Since commit a4780ade ("ARM: 7735/2: Preserve the user r/w register
TPIDRURW on context switch and fork"), arch/arm/ has context switched
the user-writable TLS register, so do the same for compat tasks running
under the arm64 kernel.
Reported-by: André Hentschel <nerv@dawncrow.de>
Tested-by: André Hentschel <nerv@dawncrow.de>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

The 32-bit ARM port doesn't have ACPI headers, and conditionally
including them is going to look horrendous. In preparation for sharing
the PSCI invocation code with 32-bit, move the acpi_psci_* function
declarations and definitions such that the PSCI client code need not
include ACPI headers.

While it would seem like we could simply hide the ACPI includes in
psci.h, the ACPI headers have hilarious circular dependencies which make
this infeasible without reorganising most of ACPICA. So rather than
doing that, move the acpi_psci_* prototypes into psci.h.

The psci_acpi_init function is made dependent on CONFIG_ACPI (with a
stub implementation in asm/psci.h) such that it need not be built for
32-bit ARM or kernels without ACPI support. The currently missing __init
annotations are added to the prototypes in the header.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Hanjun Guo <hanjun.guo@linaro.org>
Reviewed-by: Al Stone <al.stone@linaro.org>
Reviewed-by: Ashwin Chaugule <ashwin.chaugule@linaro.org>
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Will Deacon <will.deacon@arm.com>

A PSCI 1.0 implementation may choose to use the new extended StateID
format, the presence of which may be queried via the PSCI_FEATURES call.
The layout of this new StateID format is incompatible with the existing
format, and so to handle both we must abstract attempts to parse the
fields.

In preparation for PSCI 1.0 support, this patch introduces
psci_power_state_loses_context and psci_power_state_is_valid functions
to query information from a PSCI power state, which is no longer
decomposed (and hence the pack/unpack functions are removed). As it is
no longer decomposed, it is now passed round as an opaque u32 token.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Will Deacon <will.deacon@arm.com>

Software resident in the secure world (a "Trusted OS") may cause CPU_OFF
calls for the CPU it is resident on to be denied. Such a denial would be
fatal for the kernel, and so we must detect when this can happen before
the point of no return.

This patch implements Trusted OS detection for PSCI 0.2+ systems, using
MIGRATE_INFO_TYPE and MIGRATE_INFO_UP_CPU. When a trusted OS is detected
as resident on a particular CPU, attempts to hot unplug that CPU will be
denied early, before they can prove fatal.

Trusted OS migration is not implemented by this patch. Implementation of
migratable UP trusted OSs seems unlikely, and the right policy for
migration is unclear (and will likely differ across implementations). As
such, it is likely that migration will require cooperation with Trusted
OS drivers.

PSCI implementations prior to 0.1 do not provide the facility to detect
the presence of a Trusted OS, nor the CPU any such OS is resident on, so
without additional information it is not possible to handle Trusted OSs
with PSCI 0.1.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Will Deacon <will.deacon@arm.com>

PSCI_VERSION and MIGRATE_INFO_TYPE_UP_CPU return unsigned values, with
the latter returning a 64-bit value. However, the PSCI invocation
functions have prototypes returning int.

This patch upgrades the invocation functions to return unsigned long,
with a new typedef to keep things legible. As PSCI_VERSION cannot return
a negative value, the erroneous check against PSCI_RET_NOT_SUPPORTED is
also removed. The unrelated psci_initcall_t typedef is moved closer to
its first user, to avoid confusion with the invocation functions.

In preparation for sharing the code with ARM, unsigned long is used in
preference of u64. In the SMC32 calling convention, the relevant fields
will be 32 bits wide.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Will Deacon <will.deacon@arm.com>

PSCI 0.1 did not define canonical IDs for CPU_ON, CPU_OFF, CPU_SUSPEND,
or MIGRATE, and so these need to be provided when using firmware
compliant to PSCI 0.1.

However, functions introduced in 0.2 or later have canonical IDs, and
these cannot be provided via DT. There's no need to indirect the IDs via
a table; they can be used directly at callsites (and already are for
SYSTEM_OFF and SYSTEM_RESET).

This patch removes the unnecessary function ID indirection for
AFFINITY_INFO and MIGRATE_INFO_TYPE.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Will Deacon <will.deacon@arm.com>

cpu_kill currently returns one for success and zero for failure, which
is unlike all the other cpu_operations, which return zero for success
and an error code upon failure. This difference is unnecessarily
confusing.

Make cpu_kill consistent with the other cpu_operations.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Will Deacon <will.deacon@arm.com>

The PSCI MIGRATE_INFO_UP_CPU call returns a physical ID, which we will
need to map back to a Linux logical ID.

Implement a reusable get_logical_index to map from a physical ID to a
logical ID.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Will Deacon <will.deacon@arm.com>

We make use of the PSCI function IDs, but don't explicitly include the
header which defines them. Relying on transitive header includes is
fragile and will be broken as headers are refactored.

This patch includes the relevant header file directly so as to avoid
future breakage.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>

This commit removes the open-coded CPU-offline notification with new
common code.  In particular, this change avoids calling scheduler code
using RCU from an offline CPU that RCU is ignoring.  This is a minimal
change.  A more intrusive change might invoke the cpu_check_up_prepare()
and cpu_set_state_online() functions at CPU-online time, which would
allow onlining throw an error if the CPU did not go offline properly.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: linux-arm-kernel@lists.infradead.org
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

For ARM64, when tracing with tracepoint events, the IP and pstate are set
to 0, preventing the perf code parsing the callchain and resolving the
symbols correctly.

 ./perf record -e sched:sched_switch -g --call-graph dwarf ls
    [ perf record: Captured and wrote 0.146 MB perf.data ]
 ./perf report -f
    Samples: 194  of event 'sched:sched_switch', Event count (approx.): 194
    Children      Self    Command  Shared Object     Symbol
    100.00%       100.00%  ls       [unknown]         [.] 0000000000000000

The fix is to implement perf_arch_fetch_caller_regs for ARM64, which fills
several necessary registers used for callchain unwinding, including pc,sp,
fp and spsr .

With this patch, callchain can be parsed correctly as follows:

     ......
+    2.63%     0.00%  ls       [kernel.kallsyms]  [k] vfs_symlink
+    2.63%     0.00%  ls       [kernel.kallsyms]  [k] follow_down
+    2.63%     0.00%  ls       [kernel.kallsyms]  [k] pfkey_get
+    2.63%     0.00%  ls       [kernel.kallsyms]  [k] do_execveat_common.isra.33
-    2.63%     0.00%  ls       [kernel.kallsyms]  [k] pfkey_send_policy_notify
     pfkey_send_policy_notify
     pfkey_get
     v9fs_vfs_rename
     page_follow_link_light
     link_path_walk
     el0_svc_naked
    .......
Signed-off-by: Hou Pengyang <houpengyang@huawei.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

* 'for-next/cpu-init' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  ARM64: kernel: unify ACPI and DT cpus initialization
  ARM64: kernel: make cpu_ops hooks DT agnostic

The code that initializes cpus on arm64 is currently split in two
different code paths that carry out DT and ACPI cpus initialization.

Most of the code executing SMP initialization is common and should
be merged to reduce discrepancies between ACPI and DT initialization
and to have code initializing cpus in a single common place in the
kernel.

This patch refactors arm64 SMP cpus initialization code to merge
ACPI and DT boot paths in a common file and to create sanity
checks that can be reused by both boot methods.

Current code assumes PSCI is the only available boot method
when arm64 boots with ACPI; this can be easily extended if/when
the ACPI parking protocol is merged into the kernel.
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Hanjun Guo <hanjun.guo@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Tested-by: Mark Rutland <mark.rutland@arm.com> [DT]
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

ARM64 CPU operations such as cpu_init and cpu_init_idle take
a struct device_node pointer as a parameter, which corresponds to
the device tree node of the logical cpu on which the operation
has to be applied.

With the advent of ACPI on arm64, where MADT static table entries
are used to initialize cpus, the device tree node parameter
in cpu_ops hooks become useless when booting with ACPI, since
in that case cpu device tree nodes are not present and can not be
used for cpu initialization.

The current cpu_init hook requires a struct device_node pointer
parameter because it is called while parsing the device tree to
initialize CPUs, when the cpu_logical_map (that is used to match
a cpu node reg property to a device tree node) for a given logical
cpu id is not set up yet. This means that the cpu_init hook cannot
rely on the of_get_cpu_node function to retrieve the device tree
node corresponding to the logical cpu id passed in as parameter,
so the cpu device tree node must be passed in as a parameter to fix
this catch-22 dependency cycle.

This patch reshuffles the cpu_logical_map initialization code so
that the cpu_init cpu_ops hook can safely use the of_get_cpu_node
function to retrieve the cpu device tree node, removing the need for
the device tree node pointer parameter.

In the process, the patch removes device tree node parameters
from all cpu_ops hooks, in preparation for SMP DT/ACPI cpus
initialization consolidation.
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Hanjun Guo <hanjun.guo@linaro.org>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Tested-by: Mark Rutland <mark.rutland@arm.com> [DT]
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

This resolves the following sparse warning from readl() and other
macros, which ends up embedding readl_relaxed() using the same
variable.

Warning log:
include/asm-generic/io.h:364:16: warning: symbol '__v' shadows an
earlier one
include/asm-generic/io.h:364:16: originally declared here
include/asm-generic/io.h:372:16: warning: symbol '__v' shadows an
earlier one
include/asm-generic/io.h:372:16: originally declared here
include/asm-generic/io.h:380:16: warning: symbol '__v' shadows an
earlier one
include/asm-generic/io.h:380:16: originally declared here
include/asm-generic/io.h:568:16: warning: symbol '__v' shadows an
earlier one
include/asm-generic/io.h:568:16: originally declared here
include/asm-generic/io.h:576:16: warning: symbol '__v' shadows an
earlier one
include/asm-generic/io.h:576:16: originally declared here
include/asm-generic/io.h:584:16: warning: symbol '__v' shadows an
earlier one
include/asm-generic/io.h:584:16: originally declared here

The same patch was already applied to arm32 as
"ARM: 7118/1: rename temp variable in read*_relaxed()"
(sha1: b0c1264f)
Acked-by: Liviu Dudau <Liviu.Dudau@arm.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

The documented semantics of flush_cache_all are not possible to provide
for arm64 (short of flushing the entire physical address space by VA),
and there are currently no users; KVM uses VA maintenance exclusively,
cpu_reset is never called, and the only two users outside of arch code
cannot be built for arm64.

While cpu_soft_reset and related functions (which call flush_cache_all)
were thought to be useful for kexec, their current implementations only
serve to mask bugs. For correctness kexec will need to perform
maintenance by VA anyway to account for system caches, line migration,
and other subtleties of the cache architecture. As the extent of this
cache maintenance will be kexec-specific, it should probably live in the
kexec code.

This patch removes flush_cache_all, and related unused components,
preventing further abuse.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Geoff Levand <geoff@infradead.org>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Now its safe to allow forced interrupt threading for arm64,
all timer interrupts and the perf interrupt are marked NO_THREAD, as is
the case with arch/arm: da0ec6f7 ARM: 7814/2: Allow forced irq threading
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Suggested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Mark the PMU interrupts as non-threadable, as is the case with
arch/arm: d9c3365b ARM: 7813/1: Mark pmu interupt IRQF_NO_THREAD
Acked-by: Will Deacon <will.deacon@arm.com>
Suggested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Two watchdog changes that came through different trees had a non
conflicting conflict, that is, one changed the semantics of a variable
but no actual code conflict happened. So the merge appeared fine, but
the resulting code did not behave as expected.

Commit 195daf66 ("watchdog: enable the new user interface of the
watchdog mechanism") changes the semantics of watchdog_user_enabled,
which thereafter is only used by the functions introduced by
b3738d29 ("watchdog: Add watchdog enable/disable all functions").

There further appears to be a distinct lack of serialization between
setting and using watchdog_enabled, so perhaps we should wrap the
{en,dis}able_all() things in watchdog_proc_mutex.

This patch fixes a s2r failure reported by Michal; which I cannot
readily explain. But this does make the code internally consistent
again.
Reported-and-tested-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull MTD fixes from Brian Norris:
 "Two MTD fixes for 4.1:

   - readtest: the signal-handling code was clobbering the error codes
     we should be handling/reporting in this test, rendering it useless.
     Noticed by Coverity.

   - the common SPI NOR flash DT binding (merged for 4.1-rc1) is being
     revised, so let's change that before 4.1 is minted"

* tag 'for-linus-20150516' of git://git.infradead.org/linux-mtd:
  Documentation: dt: mtd: replace "nor-jedec" binding with "jedec, spi-nor"
  mtd: readtest: don't clobber error reports

Pull USB fixes from Greg KH:
 "Here are some USB fixes and new device ids for 4.1-rc4.

  All are pretty minor, and have been in linux-next successfully"

* tag 'usb-4.1-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  usb-storage: Add NO_WP_DETECT quirk for Lacie 059f:0651 devices
  Added another USB product ID for ELAN touchscreen quirks.
  xhci: gracefully handle xhci_irq dead device
  xhci: Solve full event ring by increasing TRBS_PER_SEGMENT to 256
  xhci: fix isoc endpoint dequeue from advancing too far on transaction error
  usb: chipidea: debug: avoid out of bound read
  USB: visor: Match I330 phone more precisely
  USB: pl2303: Remove support for Samsung I330
  USB: cp210x: add ID for KCF Technologies PRN device
  usb: gadget: remove incorrect __init/__exit annotations
  usb: phy: isp1301: work around tps65010 dependency
  usb: gadget: serial: fix re-ordering of tx data
  usb: gadget: hid: Fix static variable usage
  usb: gadget: configfs: Fix interfaces array NULL-termination
  usb: gadget: xilinx: fix devm_ioremap_resource() check
  usb: dwc3: dwc3-omap: correct the register macros

Pull tty/serial fixes from Greg KH:
 "Here's some TTY and serial driver fixes for reported issues.

  All of these have been in linux-next successfully"

* tag 'tty-4.1-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  pty: Fix input race when closing
  tty/n_gsm.c: fix a memory leak when gsmtty is removed
  Revert "serial/amba-pl011: Leave the TX IRQ alone when the UART is not open"
  serial: omap: Fix error handling in probe
  earlycon: Revert log warnings

Pull staging / IIO driver fixes from Greg KH:
 "Here's some staging and iio driver fixes to resolve a number of
  reported issues.

  All of these have been in linux-next for a while"

* tag 'staging-4.1-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: (31 commits)
  iio: light: hid-sensor-prox: Fix memory leak in probe()
  iio: adc: cc10001: Add delay before setting START bit
  iio: adc: cc10001: Fix regulator_get_voltage() return value check
  iio: adc: cc10001: Fix incorrect use of power-up/power-down register
  staging: gdm724x: Correction of variable usage after applying ALIGN()
  iio: adc: cc10001: Fix the channel number mapping
  staging: vt6655: lock MACvWriteBSSIDAddress.
  staging: vt6655: CARDbUpdateTSF bss timestamp correct tsf counter value.
  staging: vt6655: vnt_tx_packet Correct TX order of OWNED_BY_NIC
  staging: vt6655: Fix 80211 control and management status reporting.
  staging: vt6655: implement IEEE80211_TX_STAT_NOACK_TRANSMITTED
  staging: vt6655: device_free_tx_buf use only ieee80211_tx_status_irqsafe
  staging: vt6656: use ieee80211_tx_info to select packet type.
  staging: rtl8712: freeing an ERR_PTR
  staging: sm750: remove incorrect __exit annotation
  iio: kfifo: Set update_needed to false only if a buffer was allocated
  iio: mcp320x: Fix occasional incorrect readings
  iio: accel: mma9553: check input value for activity period
  iio: accel: mma9553: add enable channel for activity
  iio: accel: mma9551_core: prevent buffer overrun
  ...

Pull char/misc fix from Greg KH:
 "Here is one fix, in the extcon subsystem, that resolves a reported
  issue.

  It's been in linux-next for a number of weeks now, sorry for not
  getting it to you sooner"

* tag 'char-misc-4.1-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  extcon: usb-gpio: register extcon device before IRQ registration

Pull UML hostfs fix from Richard Weinberger:
 "This contains a single fix for a regression introduced in 4.1-rc1"

* 'for-linus-4.1-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
  hostfs: Use correct mask for file mode

Pull UBI bufix from Richard Weinberger:
 "This contains a single bug fix for the UBI block driver"

* tag 'upstream-4.1-rc4' of git://git.infradead.org/linux-ubifs:
  UBI: block: Add missing cache flushes

Pull ext4 fixes from Ted Ts'o:
 "Fix a number of ext4 bugs; the most serious of which is a bug in the
  lazytime mount optimization code where we could end up updating the
  timestamps to the wrong inode"

* tag 'for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: fix an ext3 collapse range regression in xfstests
  jbd2: fix r_count overflows leading to buffer overflow in journal recovery
  ext4: check for zero length extent explicitly
  ext4: fix NULL pointer dereference when journal restart fails
  ext4: remove unused function prototype from ext4.h
  ext4: don't save the error information if the block device is read-only
  ext4: fix lazytime optimization

Pull btrfs fixes from Chris Mason:
 "The first commit is a fix from Filipe for a very old extent buffer
  reuse race that triggered a BUG_ON.  It hasn't come up often, I looked
  through old logs at FB and we hit it a handful of times over the last
  year.

  The rest are other corners he hit during testing"

* 'for-linus-4.1' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: fix race when reusing stale extent buffers that leads to BUG_ON
  Btrfs: fix race between block group creation and their cache writeout
  Btrfs: fix panic when starting bg cache writeout after IO error
  Btrfs: fix crash after inode cache writeback failure