intel_th: Add Memory Storage Unit driver

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).

intel_th: Add Memory Storage Unit driver

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>

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intel_th: msu: Make stopping the trace optional

Some use cases prefer to keep collecting the trace data into the last
available window while the other windows are being offloaded instead

intel_th: msu: Make stopping the trace optional

Some use cases prefer to keep collecting the trace data into the last
available window while the other windows are being offloaded instead of
stopping the trace. In this scenario, the window switch happens
automatically when the next window becomes available again.

Add an option to allow this and a sysfs attribute to enable it.

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/20200319085152.52183-1-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Merge 5.6-rc7 into char-misc-next

We need the char/misc driver fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

intel_th: Fix user-visible error codes

There are a few places in the driver that end up returning ENOTSUPP to
the user, replace those with EINVAL.

Signed-off-by: Alexander Shish

intel_th: Fix user-visible error codes

There are a few places in the driver that end up returning ENOTSUPP to
the user, replace those with EINVAL.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Fixes: ba82664c134ef ("intel_th: Add Memory Storage Unit driver")
Cc: stable@vger.kernel.org # v4.4+
Link: https://lore.kernel.org/r/20200317062215.15598-6-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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intel_th: msu: Fix the unexpected state warning

The unexpected state warning should only warn on illegal state
transitions. Fix that.

Signed-off-by: Alexander Shishkin <alexande

intel_th: msu: Fix the unexpected state warning

The unexpected state warning should only warn on illegal state
transitions. Fix that.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Fixes: 615c164da0eb4 ("intel_th: msu: Introduce buffer interface")
Cc: stable@vger.kernel.org # v5.4+
Link: https://lore.kernel.org/r/20200317062215.15598-5-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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intel_th: Disallow multi mode on devices where it's broken

Some versions of Intel TH have an issue that prevents the multi mode of
MSU from working correctly, resulting in no trace data

intel_th: Disallow multi mode on devices where it's broken

Some versions of Intel TH have an issue that prevents the multi mode of
MSU from working correctly, resulting in no trace data and potentially
stuck MSU pipeline.

Disable multi mode on such devices.

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/20200317062215.15598-2-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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intel_th: msu: Fix window switching without windows

Commit 6cac7866c2741 ("intel_th: msu: Add a sysfs attribute to trigger
window switch") adds a NULL pointer dereference in the case whe

intel_th: msu: Fix window switching without windows

Commit 6cac7866c2741 ("intel_th: msu: Add a sysfs attribute to trigger
window switch") adds a NULL pointer dereference in the case when there are
no windows allocated:

> BUG: kernel NULL pointer dereference, address: 0000000000000000
> #PF: supervisor read access in kernel mode
> #PF: error_code(0x0000) - not-present page
> PGD 0 P4D 0
> Oops: 0000 1 SMP
> CPU: 5 PID: 1110 Comm: bash Not tainted 5.5.0-rc1+ #1
> RIP: 0010:msc_win_switch+0xa/0x80 [intel_th_msu]
> Call Trace:
> ? win_switch_store+0x9b/0xc0 [intel_th_msu]
> dev_attr_store+0x17/0x30
> sysfs_kf_write+0x3e/0x50
> kernfs_fop_write+0xda/0x1b0
> __vfs_write+0x1b/0x40
> vfs_write+0xb9/0x1a0
> ksys_write+0x67/0xe0
> __x64_sys_write+0x1a/0x20
> do_syscall_64+0x57/0x1d0
> entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fix that by disallowing window switching with multiwindow buffers without
windows.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Fixes: 6cac7866c274 ("intel_th: msu: Add a sysfs attribute to trigger window switch")
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reported-by: Ammy Yi <ammy.yi@intel.com>
Tested-by: Ammy Yi <ammy.yi@intel.com>
Cc: stable@vger.kernel.org # v5.2+
Link: https://lore.kernel.org/r/20191217115527.74383-5-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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intel_th: msu: Fix possible memory leak in mode_store()

'mode' is malloced in mode_store() and should be freed before leaving
from the error handling cases, otherwise it will cause memor

intel_th: msu: Fix possible memory leak in mode_store()

'mode' is malloced in mode_store() and should be freed before leaving
from the error handling cases, otherwise it will cause memory leak.

Fixes: 615c164da0eb ("intel_th: msu: Introduce buffer interface")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/lkml/20190801013825.182543-1-weiyongjun1@huawei.com/
Link: https://lore.kernel.org/r/20191028070651.9770-6-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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intel_th: msu: Fix overflow in shift of an unsigned int

The shift of the unsigned int win->nr_blocks by PAGE_SHIFT may
potentially overflow. Note that the intended return of this shift

intel_th: msu: Fix overflow in shift of an unsigned int

The shift of the unsigned int win->nr_blocks by PAGE_SHIFT may
potentially overflow. Note that the intended return of this shift
is expected to be a size_t however the shift is being performed as
an unsigned int. Fix this by casting win->nr_blocks to a size_t
before performing the shift.

Addresses-Coverity: ("Unintentional integer overflow")
Fixes: 615c164da0eb ("intel_th: msu: Introduce buffer interface")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/lkml/20190726113151.8967-1-colin.king@canonical.com/
Link: https://lore.kernel.org/r/20191028070651.9770-5-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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intel_th: msu: Fix missing allocation failure check on a kstrndup

Commit 615c164da0eb ("intel_th: msu: Introduce buffer interface") forgot
to add a NULL pointer check for the value retur

intel_th: msu: Fix missing allocation failure check on a kstrndup

Commit 615c164da0eb ("intel_th: msu: Introduce buffer interface") forgot
to add a NULL pointer check for the value returned from kstrdup(), which
will be troublesome if the allocation fails.

Fix that by adding the check.

Addresses-Coverity: ("Dereference null return")
Fixes: 615c164da0eb ("intel_th: msu: Introduce buffer interface")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
[alexander.shishkin: amended the commit message]
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/lkml/20190726120421.9650-1-colin.king@canonical.com/
Link: https://lore.kernel.org/r/20191028070651.9770-4-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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intel_th: msu: Fix an uninitialized mutex

Commit 615c164da0eb ("intel_th: msu: Introduce buffer interface") added a
mutex that it forgot to initialize, resulting in a lockdep splat.

intel_th: msu: Fix an uninitialized mutex

Commit 615c164da0eb ("intel_th: msu: Introduce buffer interface") added a
mutex that it forgot to initialize, resulting in a lockdep splat.

Fix that by initializing the mutex statically.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Fixes: 615c164da0eb ("intel_th: msu: Introduce buffer interface")
Link: https://lore.kernel.org/r/20191028070651.9770-3-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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intel_th: msu: Preserve pre-existing buffer configuration

The MSU configuration registers may contain buffer address/size set by
the BIOS or an external hardware debugger, which may want

intel_th: msu: Preserve pre-existing buffer configuration

The MSU configuration registers may contain buffer address/size set by
the BIOS or an external hardware debugger, which may want to take over
tracing from the driver when the driver is not actively tracing.

Preserve these settings when not actively tracing.

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/20190705141425.19894-6-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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intel_th: msu: Prevent freeing buffers while locked windows exist

We already prevent freeing buffers via sysfs interface in case there are
existing users or if trace is active. Treat the

intel_th: msu: Prevent freeing buffers while locked windows exist

We already prevent freeing buffers via sysfs interface in case there are
existing users or if trace is active. Treat the existence of locked windows
similarly and return -EBUSY on attempts to free the buffer. When the last
window is unlocked, the freeing will succeed.

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/20190705141425.19894-5-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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intel_th: msu: Get rid of the window size limit

Currently, the window size is limited to the maximum number of sg entries
in one table. This is because the code addresses individual bloc

intel_th: msu: Get rid of the window size limit

Currently, the window size is limited to the maximum number of sg entries
in one table. This is because the code addresses individual blocks within
the window by their numeric index. In reality, though, the blocks most
often are iterated through sequentially. By rewriting the logic to use sg
pointers instead of block indices we loose the necessity to dereference
them directly and gain the ability to use multiple chained tables if
necessary.

Get rid of the limitation by replacing index-based block accesses with
sequential block accesses.

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/20190705141425.19894-4-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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intel_th: msu: Introduce buffer interface

Introduces a concept of external buffers, which is a mechanism for creating
trace sinks that would receive trace data from MSC buffers and trans

intel_th: msu: Introduce buffer interface

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>

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intel_th: msu: Start read iterator from a non-empty window

In multi-window mode, the read iterator is supposed to start from the
window with the oldest data, which is, chronologically, t

intel_th: msu: Start read iterator from a non-empty window

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>

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intel_th: msu: Split sgt array and pointer in multiwindow mode

To allow the use of externally allocated SG tables further down the line,
change the code to reference the table via a poin

intel_th: msu: Split sgt array and pointer in multiwindow mode

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>

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intel_th: msu: Support multipage blocks

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

intel_th: msu: Support multipage blocks

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>

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intel_th: msu: Fix single mode with disabled IOMMU

Commit 4e0eaf239fb3 ("intel_th: msu: Fix single mode with IOMMU") switched
the single mode code to use dma mapping pages obtained from

intel_th: msu: Fix single mode with disabled IOMMU

Commit 4e0eaf239fb3 ("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: 4e0eaf239fb3 ("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>

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intel_th: msu: Remove set but not used variable 'last'

Commit aad14ad3cf3a ("intel_th: msu: Add current window tracking") added
the following gcc warning:

> drivers/hwtracing/in

intel_th: msu: Remove set but not used variable 'last'

Commit aad14ad3cf3a ("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: aad14ad3cf3a ("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>

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intel_th: msu: Fix unused variable warning on arm64 platform

Commit ba39bd8306057 ("intel_th: msu: Switch over to scatterlist")
introduced the following warnings on non-x86 architectures

intel_th: msu: Fix unused variable warning on arm64 platform

Commit ba39bd8306057 ("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: ba39bd8306057 ("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>

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intel_th: msu: Add current window tracking

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

intel_th: msu: Add current window tracking

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>

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intel_th: msu: Add a sysfs attribute to trigger window switch

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

intel_th: msu: Add a sysfs attribute to trigger window switch

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>

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intel_th: msu: Factor out pipeline draining

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

intel_th: msu: Factor out pipeline draining

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>

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intel_th: msu: Switch over to scatterlist

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 conveni

intel_th: msu: Switch over to scatterlist

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>

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