Add the BSS coex IE in case we support HT40 channels, as mandated by
section 8.5.13 in IEEE802.11 2012.
Signed-off-by: Arik Nemtsov <arikx.nemtsov@intel.com>
Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Since the TDLS peer station might not receive the teardown
packet (e.g., when in PS), this makes sure the packet is
retransmitted - this time through the AP - if the TDLS peer
didn't ACK the packet.
Signed-off-by: Liad Kaufman <liad.kaufman@intel.com>
Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Rename dm_internal_{suspend,resume} to dm_internal_{suspend,resume}_fast
-- dm-stats will continue using these methods to avoid all the extra
suspend/resume logic that is not needed in order to quickly flush IO.
Introduce dm_internal_suspend_noflush() variant that actually calls the
mapped_device's target callbacks -- otherwise target-specific hooks are
avoided (e.g. dm-thin's thin_presuspend and thin_postsuspend). Common
code between dm_internal_{suspend_noflush,resume} and
dm_{suspend,resume} was factored out as __dm_{suspend,resume}.
Update dm_internal_{suspend_noflush,resume} to always take and release
the mapped_device's suspend_lock. Also update dm_{suspend,resume} to be
aware of potential for DM_INTERNAL_SUSPEND_FLAG to be set and respond
accordingly by interruptibly waiting for the DM_INTERNAL_SUSPEND_FLAG to
be cleared. Add lockdep annotation to dm_suspend() and dm_resume().
The existing DM_SUSPEND_FLAG remains unchanged.
DM_INTERNAL_SUSPEND_FLAG is set by dm_internal_suspend_noflush() and
cleared by dm_internal_resume().
Both DM_SUSPEND_FLAG and DM_INTERNAL_SUSPEND_FLAG may be set if a device
was already suspended when dm_internal_suspend_noflush() was called --
this can be thought of as a "nested suspend". A "nested suspend" can
occur with legacy userspace dm-thin code that might suspend all active
thin volumes before suspending the pool for resize.
But otherwise, in the normal dm-thin-pool suspend case moving forward:
the thin-pool will have DM_SUSPEND_FLAG set and all active thins from
that thin-pool will have DM_INTERNAL_SUSPEND_FLAG set.
Also add DM_INTERNAL_SUSPEND_FLAG to status report. This new
DM_INTERNAL_SUSPEND_FLAG state is being reported to assist with
debugging (e.g. 'dmsetup info' will report an internally suspended
device accordingly).
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
So with all the code movement and extraction in intel_pm.c in -next
git is hopelessly confused with
commit 2208d655a9
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Fri Nov 14 09:25:29 2014 +0100
drm/i915: drop WaSetupGtModeTdRowDispatch:snb
from -fixes. Worse even small changes in -next move around the
conflict context so rerere is equally useless. Let's just backmerge
and be done with it.
Conflicts:
drivers/gpu/drm/i915/i915_drv.c
drivers/gpu/drm/i915/intel_pm.c
Except for git getting lost no tricky conflicts really.
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
The DM thin-pool target now must undo the changes performed during
pool_presuspend() so introduce presuspend_undo hook in target_type.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
This patch converts the hdev->link_keys list to be protected through
RCU, thereby eliminating the need to hold the hdev lock while accessing
the list.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
The x86 MPX patch set calls arch_unmap() and arch_bprm_mm_init()
from fs/exec.c, so we need at least a stub for them in all
architectures. They are only called under an #ifdef for
CONFIG_MMU=y, so we can at least restict this to architectures
with MMU support.
blackfin/c6x have no MMU support, so do not call arch_unmap().
They also do not include mm_hooks.h or mmu_context.h at all and
do not need to be touched.
s390, um and unicore32 do not use asm-generic/mm_hooks.h, so got
their own arch_unmap() versions. (I also moved um's
arch_dup_mmap() to be closer to the other mm_hooks.h functions).
xtensa only includes mm_hooks when MMU=y, which should be fine
since arch_unmap() is called only from MMU=y code.
For the rest, we use the stub copies of these functions in
asm-generic/mm_hook.h.
I cross compiled defconfigs for cris (to check NOMMU) and s390
to make sure that this works. I also checked a 64-bit build
of UML and all my normal x86 builds including PARAVIRT on and
off.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: linux-arch@vger.kernel.org
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/20141118182350.8B4AA2C2@viggo.jf.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Some drivers (most notably the AC'97 drivers) do not have access to their
regmap struct when the component/codec is registered. For those drivers the
automatic regmap setup will not work and needs to be done manually,
typically from the component/CODEC drivers probe callback.
This patch adds a set of helper function to handle deferred regmap
initialization as well as early regmap tear-down.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
Use the recently added support for bus operations to provide a standard
mapping for AC'97 register I/O.
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
If icmp_rcv() has successfully processed the incoming ICMP datagram, we
should use consume_skb() rather than kfree_skb() because a hit on the likes
of perf -e skb:kfree_skb is not called-for.
Signed-off-by: Rick Jones <rick.jones2@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Johan Hedberg <johan.hedberg@gmail.com> says:
"Here's another bluetooth-next pull request for 3.19. We've got:
- Various fixes, cleanups and improvements to ieee802154/mac802154
- Support for a Broadcom BCM20702A1 variant
- Lots of lockdep fixes
- Fixed handling of LE CoC errors that should trigger SMP"
Signed-off-by: John W. Linville <linville@tuxdriver.com>
expose bpf_map_lookup_elem(), bpf_map_update_elem(), bpf_map_delete_elem()
map accessors to eBPF programs
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
add new map type BPF_MAP_TYPE_ARRAY and its implementation
- optimized for fastest possible lookup()
. in the future verifier/JIT may recognize lookup() with constant key
and optimize it into constant pointer. Can optimize non-constant
key into direct pointer arithmetic as well, since pointers and
value_size are constant for the life of the eBPF program.
In other words array_map_lookup_elem() may be 'inlined' by verifier/JIT
while preserving concurrent access to this map from user space
- two main use cases for array type:
. 'global' eBPF variables: array of 1 element with key=0 and value is a
collection of 'global' variables which programs can use to keep the state
between events
. aggregation of tracing events into fixed set of buckets
- all array elements pre-allocated and zero initialized at init time
- key as an index in array and can only be 4 byte
- map_delete_elem() returns EINVAL, since elements cannot be deleted
- map_update_elem() replaces elements in an non-atomic way
(for atomic updates hashtable type should be used instead)
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
add new map type BPF_MAP_TYPE_HASH and its implementation
- maps are created/destroyed by userspace. Both userspace and eBPF programs
can lookup/update/delete elements from the map
- eBPF programs can be called in_irq(), so use spin_lock_irqsave() mechanism
for concurrent updates
- key/value are opaque range of bytes (aligned to 8 bytes)
- user space provides 3 configuration attributes via BPF syscall:
key_size, value_size, max_entries
- map takes care of allocating/freeing key/value pairs
- map_update_elem() must fail to insert new element when max_entries
limit is reached to make sure that eBPF programs cannot exhaust memory
- map_update_elem() replaces elements in an atomic way
- optimized for speed of lookup() which can be called multiple times from
eBPF program which itself is triggered by high volume of events
. in the future JIT compiler may recognize lookup() call and optimize it
further, since key_size is constant for life of eBPF program
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
the current meaning of BPF_MAP_UPDATE_ELEM syscall command is:
either update existing map element or create a new one.
Initially the plan was to add a new command to handle the case of
'create new element if it didn't exist', but 'flags' style looks
cleaner and overall diff is much smaller (more code reused), so add 'flags'
attribute to BPF_MAP_UPDATE_ELEM command with the following meaning:
#define BPF_ANY 0 /* create new element or update existing */
#define BPF_NOEXIST 1 /* create new element if it didn't exist */
#define BPF_EXIST 2 /* update existing element */
bpf_update_elem(fd, key, value, BPF_NOEXIST) call can fail with EEXIST
if element already exists.
bpf_update_elem(fd, key, value, BPF_EXIST) can fail with ENOENT
if element doesn't exist.
Userspace will call it as:
int bpf_update_elem(int fd, void *key, void *value, __u64 flags)
{
union bpf_attr attr = {
.map_fd = fd,
.key = ptr_to_u64(key),
.value = ptr_to_u64(value),
.flags = flags;
};
return bpf(BPF_MAP_UPDATE_ELEM, &attr, sizeof(attr));
}
First two bits of 'flags' are used to encode style of bpf_update_elem() command.
Bits 2-63 are reserved for future use.
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This function can only return true or false; using a bool makes it more
obvious to the reader.
Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Signed-off-by: Grant Likely <grant.likely@linaro.org>
Now that the ASoC core no longer needs a handle to the AC'97 device that is
associated with a CODEC we can remove it from the snd_soc_codec struct and
push it into the individual driver state structs like we do for other
communication buses. Doing so creates a clean separation between the AC'97
bus support and the ASoC core.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Setting the ac97_control field on a CPU DAI tells the ASoC core that this
DAI in addition to audio data also transports control data to the CODEC.
This causes the core to suspend the DAI after the CODEC and resume it before
the CODEC so communication to the CODEC is still possible. This is not
necessarily something that is specific to AC'97 and can be used by other
buses with the same requirement. This patch renames the flag from
ac97_control to bus_control to make this explicit.
While we are at it also change the type from int to bool.
The following semantich patch was used for automatic conversion of the
drivers:
// <smpl>
@@
identifier drv;
@@
struct snd_soc_dai_driver drv = {
- .ac97_control
+ .bus_control
=
- 1
+ true
};
// </smpl>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
We have all the information and dependencies we need to initialize and
register the device available in snd_soc_new_ac97_codec(). So there is no
need to delay the device registration until after the card itself as been
registered.
This makes the code significantly simpler and also makes it possible to use
the AC'97 device in the CODECs probe function. The later will be required to
be able to convert the AC'97 CODEC drivers to regmap.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
This has no users since commit f0fba2ad1b ("ASoC: multi-component - ASoC
Multi-Component Support") which was almost 5 years ago. Given that this runs
after CODEC probe functions have been run it also doesn't seem to be that
useful.
So drop it altogether to make the code simpler.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
We always pass soc_ac97_ops to snd_soc_new_ac97_codec(). So instead of
allocating a snd_ac97_bus in snd_soc_new_ac97_codec() just use a static one
that gets initialized when snd_soc_set_ac97_ops() is called.
Also drop the device number parameter from snd_soc_new_ac97_codec(). We
currently only support one device per bus and all drivers pass 0 for the
device number. And if we should ever support multiple devices per bus it
wouldn't be up to individual AC'97 device drivers to pick their number, but
rather either the AC'97 adapter driver or the core code will assign them.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Currently the AC'97 support is splattered all throughout soc-core.c. Some
parts are #ifdef'd some parts are not. This patch moves the AC'97 support to
its own file, this should make the code a bit more clearer and also makes it
possible to easily not compile it into the kernel when not needed.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
The CAN device drivers can use can_is_canfd_skb() to check if the frame to send
is on CAN FD mode or normal CAN mode.
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Dong Aisheng <b29396@freescale.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
On Intel platforms, an IO Hub (PCI/PCIe host bridge) may contain DMAR
units, so we need to support DMAR hotplug when supporting PCI host
bridge hotplug on Intel platforms.
According to Section 8.8 "Remapping Hardware Unit Hot Plug" in "Intel
Virtualization Technology for Directed IO Architecture Specification
Rev 2.2", ACPI BIOS should implement ACPI _DSM method under the ACPI
object for the PCI host bridge to support DMAR hotplug.
This patch introduces interfaces to parse ACPI _DSM method for
DMAR unit hotplug. It also implements state machines for DMAR unit
hot-addition and hot-removal.
The PCI host bridge hotplug driver should call dmar_hotplug_hotplug()
before scanning PCI devices connected for hot-addition and after
destroying all PCI devices for hot-removal.
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Reviewed-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Introduce functions to support dynamic IOMMU seq_id allocating and
releasing, which will be used to support DMAR hotplug.
Also rename IOMMU_UNITS_SUPPORTED as DMAR_UNITS_SUPPORTED.
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Reviewed-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Introduce helper function dmar_walk_resources to walk resource entries
in DMAR table and ACPI buffer object returned by ACPI _DSM method
for IOMMU hot-plug.
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This brings in some mwifiex changes that further patches will
need to work on top to not cause merge conflicts.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Implement cgroup_get_e_css() which finds and gets the effective css
for the specified cgroup and subsystem combination. This function
always returns a valid pinned css. This will be used by cgroup
writeback support.
While at it, add comment to cgroup_e_css() to explain why that
function is different from cgroup_get_e_css() and has to test
cgrp->child_subsys_mask instead of cgroup_css(cgrp, ss).
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Zefan Li <lizefan@huawei.com>
Add a new cgroup_subsys operatoin ->css_e_css_changed(). This is
invoked if any of the effective csses seen from the css's cgroup may
have changed. This will be used to implement cgroup writeback
support.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Zefan Li <lizefan@huawei.com>
Add a new cgroup subsys callback css_released(). This is called when
the reference count of the css (cgroup_subsys_state) reaches zero
before RCU scheduling free.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Zefan Li <lizefan@huawei.com>
integrity_kernel_read() duplicates the file read operations code
in vfs_read(). This patch refactors vfs_read() code creating a
helper function __vfs_read(). It is used by both vfs_read() and
integrity_kernel_read().
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Keys can only be loaded once the rootfs is mounted. Initcalls
are not suitable for that. This patch defines a special hook
to load the x509 public keys onto the IMA keyring, before
attempting to access any file. The keys are required for
verifying the file's signature. The hook is called after the
root filesystem is mounted and before the kernel calls 'init'.
Changes in v3:
* added more explanation to the patch description (Mimi)
Changes in v2:
* Hook renamed as 'integrity_load_keys()' to handle both IMA and EVM
keys by integrity subsystem.
* Hook patch moved after defining loading functions
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
The common short form of "randomizer" is "rand" in many places
(including the Bluetooth specification). The shorter version also makes
for easier to read code with less forced line breaks. This patch renames
all occurences of "randomizer" to "rand" in the Bluetooth subsystem
code.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
The definition of the struct pm_domain_data better belongs in the
header for the PM domains, let's move it there.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The previous patch allocates bounds tables on-demand. As noted in
an earlier description, these can add up to *HUGE* amounts of
memory. This has caused OOMs in practice when running tests.
This patch adds support for freeing bounds tables when they are no
longer in use.
There are two types of mappings in play when unmapping tables:
1. The mapping with the actual data, which userspace is
munmap()ing or brk()ing away, etc...
2. The mapping for the bounds table *backing* the data
(is tagged with VM_MPX, see the patch "add MPX specific
mmap interface").
If userspace use the prctl() indroduced earlier in this patchset
to enable the management of bounds tables in kernel, when it
unmaps the first type of mapping with the actual data, the kernel
needs to free the mapping for the bounds table backing the data.
This patch hooks in at the very end of do_unmap() to do so.
We look at the addresses being unmapped and find the bounds
directory entries and tables which cover those addresses. If
an entire table is unused, we clear associated directory entry
and free the table.
Once we unmap the bounds table, we would have a bounds directory
entry pointing at empty address space. That address space might
now be allocated for some other (random) use, and the MPX
hardware might now try to walk it as if it were a bounds table.
That would be bad. So any unmapping of an enture bounds table
has to be accompanied by a corresponding write to the bounds
directory entry to invalidate it. That write to the bounds
directory can fault, which causes the following problem:
Since we are doing the freeing from munmap() (and other paths
like it), we hold mmap_sem for write. If we fault, the page
fault handler will attempt to acquire mmap_sem for read and
we will deadlock. To avoid the deadlock, we pagefault_disable()
when touching the bounds directory entry and use a
get_user_pages() to resolve the fault.
The unmapping of bounds tables happends under vm_munmap(). We
also (indirectly) call vm_munmap() to _do_ the unmapping of the
bounds tables. We avoid unbounded recursion by disallowing
freeing of bounds tables *for* bounds tables. This would not
occur normally, so should not have any practical impact. Being
strict about it here helps ensure that we do not have an
exploitable stack overflow.
Based-on-patch-by: Qiaowei Ren <qiaowei.ren@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-mm@kvack.org
Cc: linux-mips@linux-mips.org
Cc: Dave Hansen <dave@sr71.net>
Link: http://lkml.kernel.org/r/20141114151831.E4531C4A@viggo.jf.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This is really the meat of the MPX patch set. If there is one patch to
review in the entire series, this is the one. There is a new ABI here
and this kernel code also interacts with userspace memory in a
relatively unusual manner. (small FAQ below).
Long Description:
This patch adds two prctl() commands to provide enable or disable the
management of bounds tables in kernel, including on-demand kernel
allocation (See the patch "on-demand kernel allocation of bounds tables")
and cleanup (See the patch "cleanup unused bound tables"). Applications
do not strictly need the kernel to manage bounds tables and we expect
some applications to use MPX without taking advantage of this kernel
support. This means the kernel can not simply infer whether an application
needs bounds table management from the MPX registers. The prctl() is an
explicit signal from userspace.
PR_MPX_ENABLE_MANAGEMENT is meant to be a signal from userspace to
require kernel's help in managing bounds tables.
PR_MPX_DISABLE_MANAGEMENT is the opposite, meaning that userspace don't
want kernel's help any more. With PR_MPX_DISABLE_MANAGEMENT, the kernel
won't allocate and free bounds tables even if the CPU supports MPX.
PR_MPX_ENABLE_MANAGEMENT will fetch the base address of the bounds
directory out of a userspace register (bndcfgu) and then cache it into
a new field (->bd_addr) in the 'mm_struct'. PR_MPX_DISABLE_MANAGEMENT
will set "bd_addr" to an invalid address. Using this scheme, we can
use "bd_addr" to determine whether the management of bounds tables in
kernel is enabled.
Also, the only way to access that bndcfgu register is via an xsaves,
which can be expensive. Caching "bd_addr" like this also helps reduce
the cost of those xsaves when doing table cleanup at munmap() time.
Unfortunately, we can not apply this optimization to #BR fault time
because we need an xsave to get the value of BNDSTATUS.
==== Why does the hardware even have these Bounds Tables? ====
MPX only has 4 hardware registers for storing bounds information.
If MPX-enabled code needs more than these 4 registers, it needs to
spill them somewhere. It has two special instructions for this
which allow the bounds to be moved between the bounds registers
and some new "bounds tables".
They are similar conceptually to a page fault and will be raised by
the MPX hardware during both bounds violations or when the tables
are not present. This patch handles those #BR exceptions for
not-present tables by carving the space out of the normal processes
address space (essentially calling the new mmap() interface indroduced
earlier in this patch set.) and then pointing the bounds-directory
over to it.
The tables *need* to be accessed and controlled by userspace because
the instructions for moving bounds in and out of them are extremely
frequent. They potentially happen every time a register pointing to
memory is dereferenced. Any direct kernel involvement (like a syscall)
to access the tables would obviously destroy performance.
==== Why not do this in userspace? ====
This patch is obviously doing this allocation in the kernel.
However, MPX does not strictly *require* anything in the kernel.
It can theoretically be done completely from userspace. Here are
a few ways this *could* be done. I don't think any of them are
practical in the real-world, but here they are.
Q: Can virtual space simply be reserved for the bounds tables so
that we never have to allocate them?
A: As noted earlier, these tables are *HUGE*. An X-GB virtual
area needs 4*X GB of virtual space, plus 2GB for the bounds
directory. If we were to preallocate them for the 128TB of
user virtual address space, we would need to reserve 512TB+2GB,
which is larger than the entire virtual address space today.
This means they can not be reserved ahead of time. Also, a
single process's pre-popualated bounds directory consumes 2GB
of virtual *AND* physical memory. IOW, it's completely
infeasible to prepopulate bounds directories.
Q: Can we preallocate bounds table space at the same time memory
is allocated which might contain pointers that might eventually
need bounds tables?
A: This would work if we could hook the site of each and every
memory allocation syscall. This can be done for small,
constrained applications. But, it isn't practical at a larger
scale since a given app has no way of controlling how all the
parts of the app might allocate memory (think libraries). The
kernel is really the only place to intercept these calls.
Q: Could a bounds fault be handed to userspace and the tables
allocated there in a signal handler instead of in the kernel?
A: (thanks to tglx) mmap() is not on the list of safe async
handler functions and even if mmap() would work it still
requires locking or nasty tricks to keep track of the
allocation state there.
Having ruled out all of the userspace-only approaches for managing
bounds tables that we could think of, we create them on demand in
the kernel.
Based-on-patch-by: Qiaowei Ren <qiaowei.ren@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-mm@kvack.org
Cc: linux-mips@linux-mips.org
Cc: Dave Hansen <dave@sr71.net>
Link: http://lkml.kernel.org/r/20141114151829.AD4310DE@viggo.jf.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
MPX-enabled applications using large swaths of memory can
potentially have large numbers of bounds tables in process
address space to save bounds information. These tables can take
up huge swaths of memory (as much as 80% of the memory on the
system) even if we clean them up aggressively. In the worst-case
scenario, the tables can be 4x the size of the data structure
being tracked. IOW, a 1-page structure can require 4 bounds-table
pages.
Being this huge, our expectation is that folks using MPX are
going to be keen on figuring out how much memory is being
dedicated to it. So we need a way to track memory use for MPX.
If we want to specifically track MPX VMAs we need to be able to
distinguish them from normal VMAs, and keep them from getting
merged with normal VMAs. A new VM_ flag set only on MPX VMAs does
both of those things. With this flag, MPX bounds-table VMAs can
be distinguished from other VMAs, and userspace can also walk
/proc/$pid/smaps to get memory usage for MPX.
In addition to this flag, we also introduce a special ->vm_ops
specific to MPX VMAs (see the patch "add MPX specific mmap
interface"), but currently different ->vm_ops do not by
themselves prevent VMA merging, so we still need this flag.
We understand that VM_ flags are scarce and are open to other
options.
Signed-off-by: Qiaowei Ren <qiaowei.ren@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-mm@kvack.org
Cc: linux-mips@linux-mips.org
Cc: Dave Hansen <dave@sr71.net>
Link: http://lkml.kernel.org/r/20141114151825.565625B3@viggo.jf.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The version field defined in the audit status structure was found to have
limitations in terms of its expressibility of features supported. This is
distict from the get/set features call to be able to command those features
that are present.
Converting this field from a version number to a feature bitmap will allow
distributions to selectively backport and support certain features and will
allow upstream to be able to deprecate features in the future. It will allow
userspace clients to first query the kernel for which features are actually
present and supported. Currently, EINVAL is returned rather than EOPNOTSUP,
which isn't helpful in determining if there was an error in the command, or if
it simply isn't supported yet. Past features are not represented by this
bitmap, but their use may be converted to EOPNOTSUP if needed in the future.
Since "version" is too generic to convert with a #define, use a union in the
struct status, introducing the member "feature_bitmap" unionized with
"version".
Convert existing AUDIT_VERSION_* macros over to AUDIT_FEATURE_BITMAP*
counterparts, leaving the former for backwards compatibility.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
[PM: minor whitespace tweaks]
Signed-off-by: Paul Moore <pmoore@redhat.com>
