ARM: 7467/1: mutex: use generic xchg-based implementation for ARMv6+

The open-coded mutex implementation for ARMv6+ cores suffers from a
severe lack of barriers, so in the uncontended case we don't actually
protect any accesses performed during the critical section.

Furthermore, the code is largely a duplication of the ARMv6+ atomic_dec
code but optimised to remove a branch instruction, as the mutex fastpath
was previously inlined. Now that this is executed out-of-line, we can
reuse the atomic access code for the locking (in fact, we use the xchg
code as this produces shorter critical sections).

This patch uses the generic xchg based implementation for mutexes on
ARMv6+, which introduces barriers to the lock/unlock operations and also
has the benefit of removing a fair amount of inline assembly code.

Change-Id: I58e3ca4d2740a834d30b54fc35742fa2df7792ad
Cc: <stable@vger.kernel.org> : 0bce9c46: mutex: Place lock in contended...
Cc: <stable@vger.kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Nicolas Pitre <nico@linaro.org>
Reported-by: Shan Kang <kangshan0910@gmail.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Reviewed-on: http://git-master/r/130940
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>
Tested-by: Bharat Nihalani <bnihalani@nvidia.com>
Signed-off-by: Paul Reioux <reioux@gmail.com>
ARM: mutex: use generic atomic_dec-based implementation for ARMv6+

Commit a76d7bd96d65 ("ARM: 7467/1: mutex: use generic xchg-based
implementation for ARMv6+") removed the barrier-less, ARM-specific
mutex implementation in favour of the generic xchg-based code.

Since then, a bug was uncovered in the xchg code when running on SMP
platforms, due to interactions between the locking paths and the
MUTEX_SPIN_ON_OWNER code. This was fixed in 0bce9c46bf3b ("mutex: place
lock in contended state after fastpath_lock failure"), however, the
atomic_dec-based mutex algorithm is now marginally more efficient for
ARM (~0.5% improvement in hackbench scores on dual A15).

This patch moves ARMv6+ platforms to the atomic_dec-based mutex code.

Change-Id: I8f64e98ccb61cc1cb9cb68ee15e55d8a792792f5
Cc: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Reviewed-on: http://git-master/r/130941
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>
Tested-by: Bharat Nihalani <bnihalani@nvidia.com>
cpufreq: Resolve CPUFREQ_NOTIFY issue

When the cpufreq_stat receives the frequency policy notification,
it checks if the frequency table and stats table are present for the cpu.
If both are present, it returns with -EBUSY error to the notification.
Due to this, none of the other registered modules receive this
notification.

If the stat table and sysfs nodes are already created, return 0 instead
of returning EBUSY error.

Change-Id: I1fd4a46e6a65edfc6253c4271288f10912ae2ad7
Signed-off-by: Archana Sathyakumar <asathyak@codeaurora.org>
cpufreq: Retain only online cpus in managed_policy->cpus

cpufreq's handling of cpu online event can incorrectly initialize
managed_policy->cpus to include offline cpus. This causes cpufreq
governors to include offline cpus in their idle time computation, which
causes frequency to shoot up beyond normal levels (on systems where 2 or
more cpus need to be synchronized wrt frequency change).

This frequency shootup was not seen prior to commit 21111be8 which
changed idle time accounting for offline cpus. Prior to commit 21111be8,
idle time statistics for offline cpus would include their offline time
as well. Post commit 21111be8, offline time is not included in a cpu's
idle time statistics.

As a result, ondemand (or other cpufreq) governors would see unchanged
idle time for offline cpus, causing them to interpret those (offline)
cpus as 100% busy, which is wrong.

This patch fixes the issue by modifying cpufreq's hotplug handling to
retain only online cpus in managed_policy->cpus field. cpufreq governors
would then skip such offline cpus from idle time calculations.

Change-Id: Id2eba8c0ec3367609369b2e42a4e1386ff2e7ab5
Signed-off-by: Srivatsa Vaddagiri <vatsa@codeaurora.org>
ARM: 7421/1: bpf_jit: BPF_S_ANC_ALU_XOR_X support

JIT support for the XOR operation introduced by the commit
ffe06c17afbb.

Signed-off-by: Mircea Gherzan <mgherzan@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: net: bpf_jit_32: add XOR instruction for BPF JIT

This patch is a follow-up for patch "filter: add XOR instruction for use
with X/K" that implements BPF ARM JIT parts for the BPF XOR operation.

Signed-off-by: Daniel Borkmann <daniel.borkmann@tik.ee.ethz.ch>
Cc: Mircea Gherzan <mgherzan@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: Mircea Gherzan <mgherzan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
ARM: net: bpf_jit_32: add VLAN instructions for BPF JIT

This patch is a follow-up for patch "net: filter: add vlan tag access"
to support the new VLAN_TAG/VLAN_TAG_PRESENT accessors in BPF JIT.

Signed-off-by: Daniel Borkmann <daniel.borkmann@tik.ee.ethz.ch>
Cc: Mircea Gherzan <mgherzan@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: Mircea Gherzan <mgherzan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
ARM: 7597/1: net: bpf_jit_32: fix kzalloc gfp/size mismatch.

Official prototype for kzalloc is:

void *kzalloc(size_t, gfp_t);

The ARM bpf_jit code was having the assumption that it was:

void *kzalloc(gfp_t, size);

This was resulting the use of some random GFP flags depending on the
size requested and some random overflows once the really needed size
was more than the value of GFP_KERNEL.

This bug was present since the original inclusion of bpf_jit for ARM
(ddecdfce: ARM: 7259/3: net: JIT compiler for packet filters).

Signed-off-by: Nicolas Schichan <nschichan@freebox.fr>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: 7598/1: net: bpf_jit_32: fix sp-relative load/stores offsets.

The offset must be multiplied by 4 to be sure to access the correct
32bit word in the stack scratch space.

For instance, a store at scratch memory cell #1 was generating the
following:

st	r4, [sp, #1]

While the correct code for this is:

st	r4, [sp, #4]

To reproduce the bug (assuming your system has a NIC with the mac
address 52:54:00:12:34:56):

echo 0 > /proc/sys/net/core/bpf_jit_enable
tcpdump -ni eth0 "ether[1] + ether[2] - ether[3] * ether[4] - ether[5] \
	== -0x3AA" # this will capture packets as expected

echo 1 > /proc/sys/net/core/bpf_jit_enable
tcpdump -ni eth0 "ether[1] + ether[2] - ether[3] * ether[4] - ether[5] \
	== -0x3AA" # this will not.

This bug was present since the original inclusion of bpf_jit for ARM
(ddecdfce: ARM: 7259/3: net: JIT compiler for packet filters).

Signed-off-by: Nicolas Schichan <nschichan@freebox.fr>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: net: bpf_jit: fix emit_swap16() for non ARMv6+.

The original code was generating an lsl instructions using the value
of ARM_R8 (skb_headlen, possibly uninitialized if no skb_headlen
access was required) as a shift amount.

Signed-off-by: Nicolas Schichan <nschichan@freebox.fr>
Acked-by: Mircea Gherzan <mgherzan@gmail.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
ARM:net: an issue for k which is u32, never < 0

  k is u32 which never < 0, need type cast, or cause issue.

Signed-off-by: Chen Gang <gang.chen@asianux.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Mircea Gherzan <mgherzan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
filter: Allow to create sk-unattached filters

Today, BPF filters are bind to sockets. Since BPF machine becomes handy
for other purposes, this patch allows to create unattached filter.

Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
filter: add XOR operation

Add XOR instruction fo BPF machine. Needed for computing packet hashes.

Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sk_run_filter: add BPF_S_ANC_SECCOMP_LD_W

Introduces a new BPF ancillary instruction that all LD calls will be
mapped through when skb_run_filter() is being used for seccomp BPF.  The
rewriting will be done using a secondary chk_filter function that is run
after skb_chk_filter.

The code change is guarded by CONFIG_SECCOMP_FILTER which is added,
along with the seccomp_bpf_load() function later in this series.

This is based on http://lkml.org/lkml/2012/3/2/141

Suggested-by: Indan Zupancic <indan@nul.nu>
Signed-off-by: Will Drewry <wad@chromium.org>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Eric Paris <eparis@redhat.com>

v18: rebase
...
v15: include seccomp.h explicitly for when seccomp_bpf_load exists.
v14: First cut using a single additional instruction
... v13: made bpf functions generic.
Signed-off-by: James Morris <james.l.morris@oracle.com>

Conflicts:
	include/linux/filter.h
net/compat.c,linux/filter.h: share compat_sock_fprog

Any other users of bpf_*_filter that take a struct sock_fprog from
userspace will need to be able to also accept a compat_sock_fprog
if the arch supports compat calls.  This change allows the existing
compat_sock_fprog be shared.

Signed-off-by: Will Drewry <wad@chromium.org>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Eric Paris <eparis@redhat.com>

v18: tasered by the apostrophe police
v14: rebase/nochanges
v13: rebase on to 88ebdda6159ffc15699f204c33feb3e431bf9bdc
v12: rebase on to linux-next
v11: introduction
Signed-off-by: James Morris <james.l.morris@oracle.com>
filter: add MOD operation

Add a new ALU opcode, to compute a modulus.

Commit ffe06c17afbbb used an ancillary to implement XOR_X,
but here we reserve one of the available ALU opcode to implement both
MOD_X and MOD_K

Signed-off-by: Eric Dumazet <edumazet@google.com>
Suggested-by: George Bakos <gbakos@alpinista.org>
Cc: Jay Schulist <jschlst@samba.org>
Cc: Jiri Pirko <jpirko@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
filter: add XOR instruction for use with X/K

SKF_AD_ALU_XOR_X has been added a while ago, but as an 'ancillary'
operation that is invoked through a negative offset in K within BPF
load operations. Since BPF_MOD has recently been added, BPF_XOR should
also be part of the common ALU operations. Removing SKF_AD_ALU_XOR_X
might not be an option since this is exposed to user space.

Signed-off-by: Daniel Borkmann <daniel.borkmann@tik.ee.ethz.ch>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net: filter: add vlan tag access

BPF filters lack ability to access skb->vlan_tci

This patch adds two new ancillary accessors :

SKF_AD_VLAN_TAG         (44) mapped to vlan_tx_tag_get(skb)

SKF_AD_VLAN_TAG_PRESENT (48) mapped to vlan_tx_tag_present(skb)

This allows libpcap/tcpdump to use a kernel filter instead of
having to fallback to accept all packets, then filter them in
user space.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Suggested-by: Ani Sinha <ani@aristanetworks.com>
Suggested-by: Daniel Borkmann <danborkmann@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
modified for mako kernel form Linux 3.9+

Signed-off-by: Paul Reioux <reioux@gmail.com>
ARM: 7461/1: topology: Add arch_scale_freq_power function

Add infrastructure to be able to modify the cpu_power of each core

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: 7462/1: topology: factorize the update of sibling masks

This factorization has also been proposed in another patch that has not been
merged yet:
http://lists.infradead.org/pipermail/linux-arm-kernel/2012-January/080873.html
So, this patch could be dropped depending of the state of the other one.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>