Introduces a concept of external buffers, which is a mechanism for creating
trace sinks that would receive trace data from MSC buffers and transfer it
elsewhere.
A external buffer can implement its own window allocation/deallocation if
it has to. It must provide a callback that's used to notify it when a
window fills up, so that it can then start a DMA transaction from that
window 'elsewhere'. This window remains in a 'locked' state and won't be
used for storing new trace data until the buffer 'unlocks' it with a
provided API call, at which point the window can be used again for storing
trace data.
This relies on a functional "last block" interrupt, so not all versions of
Trace Hub can use this feature, which does not reflect on existing users.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20190705141425.19894-2-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In multi-window mode, the read iterator is supposed to start from the
window with the oldest data, which is, chronologically, the next window
after the one with the newest data. This, however, fails to take into
account the potentially empty windows, so in short trace sessions it's
possible to have a lot of zeroes read from the character device first.
Fix this by skipping over the empty windows in initialization of the
read iterator.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20190627125152.54905-5-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To allow the use of externally allocated SG tables further down the line,
change the code to reference the table via a pointer and make it point to
the locally allocated table by default.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20190627125152.54905-4-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Now that the MSU is using scatterlist, we can support multipage blocks.
At the moment, the code assumes that all blocks are page-sized, but in
larger buffers it may make sense to chunk together larger blocks of
memory. One place where one-to-many relationship needs to be handled is
the MSU buffer's mmap path.
Get rid of the implicit assumption that all blocks are page-sized.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20190627125152.54905-3-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 4e0eaf239f ("intel_th: msu: Fix single mode with IOMMU") switched
the single mode code to use dma mapping pages obtained from the page
allocator, but with IOMMU disabled, that may lead to using SWIOTLB bounce
buffers and without additional sync'ing, produces empty trace buffers.
Fix this by using a DMA32 GFP flag to the page allocation in single mode,
as the device supports full 32-bit DMA addressing.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Fixes: 4e0eaf239f ("intel_th: msu: Fix single mode with IOMMU")
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reported-by: Ammy Yi <ammy.yi@intel.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20190621161930.60785-4-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit aad14ad3cf ("intel_th: msu: Add current window tracking") added
the following gcc warning:
> drivers/hwtracing/intel_th/msu.c: In function msc_win_switch:
> drivers/hwtracing/intel_th/msu.c:1389:21: warning: variable last set but
> not used [-Wunused-but-set-variable]
Fix it by removing the variable.
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Fixes: aad14ad3cf ("intel_th: msu: Add current window tracking")
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20190621161930.60785-3-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit ba39bd8306 ("intel_th: msu: Switch over to scatterlist")
introduced the following warnings on non-x86 architectures, as a result
of reordering the multi mode buffer allocation sequence:
> drivers/hwtracing/intel_th/msu.c: In function ‘msc_buffer_win_alloc’:
> drivers/hwtracing/intel_th/msu.c:783:21: warning: unused variable ‘i’
> [-Wunused-variable]
> int ret = -ENOMEM, i;
> ^
> drivers/hwtracing/intel_th/msu.c: In function ‘msc_buffer_win_free’:
> drivers/hwtracing/intel_th/msu.c:863:6: warning: unused variable ‘i’
> [-Wunused-variable]
> int i;
> ^
Fix this compiler warning by factoring out set_memory sequences and making
them x86-only.
Suggested-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Fixes: ba39bd8306 ("intel_th: msu: Switch over to scatterlist")
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20190621161930.60785-2-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Now that we have a way to switch between MSC buffer windows, add code to
track the current window. The hardware register NWSA that contains the
address of the next window is unfortunately not always usable, and since
the driver has full control of the window switching, there is no reason
not to keep this on the software side.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Now that we have the means to trigger a window switch for the MSU trace
store, add a sysfs file to allow triggering it from userspace.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The code that waits for the pipeline empty condition of the MSU is
currently called in the path that disables the trace. We will also
need this in the window switch trigger sequence. Therefore, factor
out this code and make it accessible to the GTH device.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Instead of using a home-grown array of pointers to the DMA pages, switch
over to scatterlist data types and accessors, which has all the convenient
accessors, can be used to batch-map DMA memory and is convenient for
passing around between different layers, which will be useful when MSU
buffer management has to cross the boundaries of the MSU driver.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There are a few places in the code where open-coded versions of list entry
accessors list_first_entry()/list_last_entry()/list_next_entry() are used.
Replace those with the standard macros.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We intend to use the interrupt to detect Last Block condition in the MSU
driver, which we can use for double-buffering software-managed data
transfers.
Add an interrupt handler to the MSU driver.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently, the pages that are allocated for the single mode of MSC are not
mapped into the device's dma space and the code is incorrectly using
*_to_phys() in place of a dma address. This fails with IOMMU enabled and
is otherwise bad practice.
Fix the single mode buffer allocation to map the pages into the device's
DMA space.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Fixes: ba82664c13 ("intel_th: Add Memory Storage Unit driver")
Cc: stable@vger.kernel.org # v4.4+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The 'nr_pages' attribute of the 'msc' subdevices parses a comma-separated
list of window sizes, passed from userspace. However, there is a bug in
the string parsing logic wherein it doesn't exclude the comma character
from the range of characters as it consumes them. This leads to an
out-of-bounds access given a sufficiently long list. For example:
> # echo 8,8,8,8 > /sys/bus/intel_th/devices/0-msc0/nr_pages
> ==================================================================
> BUG: KASAN: slab-out-of-bounds in memchr+0x1e/0x40
> Read of size 1 at addr ffff8803ffcebcd1 by task sh/825
>
> CPU: 3 PID: 825 Comm: npktest.sh Tainted: G W 4.20.0-rc1+
> Call Trace:
> dump_stack+0x7c/0xc0
> print_address_description+0x6c/0x23c
> ? memchr+0x1e/0x40
> kasan_report.cold.5+0x241/0x308
> memchr+0x1e/0x40
> nr_pages_store+0x203/0xd00 [intel_th_msu]
Fix this by accounting for the comma character.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Fixes: ba82664c13 ("intel_th: Add Memory Storage Unit driver")
Cc: stable@vger.kernel.org # v4.4+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use new return type vm_fault_t for fault handler. For now, this is just
documenting that the function returns a VM_FAULT value rather than an
errno. Once all instances are converted, vm_fault_t will become a
distinct type.
See 1c8f422059 ("mm: change return type to vm_fault_t") for reference.
Link: http://lkml.kernel.org/r/20180702155801.GA4010@jordon-HP-15-Notebook-PC
Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit d5c435df4a ("intel_th: msu: Use the real device in case of IOMMU
domain allocation") changes dma buffer allocation to use the actual
underlying device, but forgets to change the deallocation path, which leads
to (if you've got CAP_SYS_RAWIO):
> # echo 0,0 > /sys/bus/intel_th/devices/0-msc0/nr_pages
> ------------[ cut here ]------------
> kernel BUG at ../linux/drivers/iommu/intel-iommu.c:3670!
> CPU: 3 PID: 231 Comm: sh Not tainted 4.17.0-rc1+ #2729
> RIP: 0010:intel_unmap+0x11e/0x130
...
> Call Trace:
> intel_free_coherent+0x3e/0x60
> msc_buffer_win_free+0x100/0x160 [intel_th_msu]
This patch fixes the buffer deallocation code to use the correct device.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Fixes: d5c435df4a ("intel_th: msu: Use the real device in case of IOMMU domain allocation")
Reported-by: Baofeng Tian <baofeng.tian@intel.com>
CC: stable@vger.kernel.org # v4.14+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This adds SPDX GPL-2.0 header to the Trace Hub driver and removes the
GPLv2 boilerplate text.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
set_memory_* functions have moved to set_memory.h. Switch to this
explicitly.
Link: http://lkml.kernel.org/r/1488920133-27229-9-git-send-email-labbott@redhat.com
Signed-off-by: Laura Abbott <labbott@redhat.com>
Acked-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
->fault(), ->page_mkwrite(), and ->pfn_mkwrite() calls do not need to
take a vma and vmf parameter when the vma already resides in vmf.
Remove the vma parameter to simplify things.
[arnd@arndb.de: fix ARM build]
Link: http://lkml.kernel.org/r/20170125223558.1451224-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/148521301778.19116.10840599906674778980.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jan Kara <jack@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Here's the big char and misc driver update for 4.7-rc1.
Lots of different tiny driver subsystems have updates here with new
drivers and functionality. Details in the shortlog.
All have been in linux-next with no reported issues for a while.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'char-misc-4.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
Pull char / misc driver updates from Greg KH:
"Here's the big char and misc driver update for 4.7-rc1.
Lots of different tiny driver subsystems have updates here with new
drivers and functionality. Details in the shortlog.
All have been in linux-next with no reported issues for a while"
* tag 'char-misc-4.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (125 commits)
mcb: Delete num_cells variable which is not required
mcb: Fixed bar number assignment for the gdd
mcb: Replace ioremap and request_region with the devm version
mcb: Implement bus->dev.release callback
mcb: export bus information via sysfs
mcb: Correctly initialize the bus's device
mei: bus: call mei_cl_read_start under device lock
coresight: etb10: adjust read pointer only when needed
coresight: configuring ETF in FIFO mode when acting as link
coresight: tmc: implementing TMC-ETF AUX space API
coresight: moving struct cs_buffers to header file
coresight: tmc: keep track of memory width
coresight: tmc: make sysFS and Perf mode mutually exclusive
coresight: tmc: dump system memory content only when needed
coresight: tmc: adding mode of operation for link/sinks
coresight: tmc: getting rid of multiple read access
coresight: tmc: allocating memory when needed
coresight: tmc: making prepare/unprepare functions generic
coresight: tmc: splitting driver in ETB/ETF and ETR components
coresight: tmc: cleaning up header file
...
Many developers already know that field for reference count of the
struct page is _count and atomic type. They would try to handle it
directly and this could break the purpose of page reference count
tracepoint. To prevent direct _count modification, this patch rename it
to _refcount and add warning message on the code. After that, developer
who need to handle reference count will find that field should not be
accessed directly.
[akpm@linux-foundation.org: fix comments, per Vlastimil]
[akpm@linux-foundation.org: Documentation/vm/transhuge.txt too]
[sfr@canb.auug.org.au: sync ethernet driver changes]
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Sunil Goutham <sgoutham@cavium.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Manish Chopra <manish.chopra@qlogic.com>
Cc: Yuval Mintz <yuval.mintz@qlogic.com>
Cc: Tariq Toukan <tariqt@mellanox.com>
Cc: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Do release the resources when msu subdevice gets removed: stop the
capture if it is active (which is still possible even though the
module in pinned) and free the capture buffers.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Laurent Fert <laurent.fert@intel.com>
Right now it's possible to unload the msu driver while its character
device is open. Prevent it by setting fops::owner, which will result
in the module reference being held while the device node is open.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Laurent Fert <laurent.fert@intel.com>
In order to guarantee that readers don't race with trace enabling,
both should happen under the same mutex. Having two mutexes seems
like an overkill, considering that because of the above, they'll
have to be acquired together, around trace enabling and char device
opening.
This patch makes both buffer accesses and readers serialize on
msc::buf_mutex and makes sure that 'enabled' flag accesses are also
serialized on it.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Laurent Fert <laurent.fert@intel.com>
The core intel_th driver allows subdevices to bring in their sysfs
attributes. Use this instead of taking care of them in probe and
remove.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Laurent Fert <laurent.fert@intel.com>
Currently, the nr_pages attribute store does not check if kstrndup()
succeeded. Fix this.
Reported-by: Alan Cox <alan.cox@intel.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Laurent Fert <laurent.fert@intel.com>
Right now, reading from msc character device will leak its's user count
on read error.
This patch makes sure resources are released when there is no data left
to read from the buffer.
Signed-off-by: Laurent FERT <laurent.fert@intel.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fix offset for the second pass on the wrapped block when iterating over
memory in multi-block mode, otherwise wrong part of the block will get
copied.
Signed-off-by: Laurent FERT <laurent.fert@intel.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
devm_ioremap() returns NULL on error, it doesn't return an ERR_PTR,
which is what the current code does. This patch corrects these
checks.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use unsigned long in place of size_t to operate on buffer sizes and
offsets to clean up the 32 bit build.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Memory Storage Unit (MSU) is a trace output device that collects trace
data to system memory. It consists of 2 independent Memory Storage
Controllers (MSCs).
This driver provides userspace interfaces to configure in-memory tracing
parameters, such as contiguous (high-order allocation) buffer or multiblock
(scatter list) buffer mode, wrapping (data overwrite) and number and sizes
of windows in multiblock mode. Userspace can read the buffers via mmap()ing
or read()ing of the corresponding device node.
Signed-off-by: Laurent Fert <laurent.fert@intel.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Alexander Shishkin