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We get a few warnings when building kernel with W=1:
drivers/hwtracing/coresight/coresight-tmc-etr.c:23:6: warning: no previous prototype for 'tmc_etr_enable_hw' [-Wmissing-prototypes]
drivers/hwtracing/coresight/coresight-tmc-etf.c:25:6: warning: no previous prototype for 'tmc_etb_enable_hw' [-Wmissing-prototypes]
drivers/hwtracing/coresight/coresight-tmc.c:250:9: warning: no previous prototype for ‘trigger_cntr_show’ [-Wmissing-prototypes]
...
In fact, these functions are only used in the file in which they are
declared and don't need a declaration, but can be made static.
so this patch marks these functions with 'static'.
Signed-off-by: Baoyou Xie <baoyou.xie@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Use the defined symbol rather than hardcoding the value to
check whether the TMC buffer is full.
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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At present the ETF or ETR gives out the entire device
buffer, even if there is less or even no trace data
available. This patch limits the trace data given out to
the actual trace data collected.
Cc: mathieu.poirier@linaro.org
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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At the end of a trace collection, we try to clear the entire buffer
and enable the ETR back if it was already enabled. But, we would have
adjusted the drvdata->buf to point to the beginning of the trace data
in the trace buffer @drvdata->vaddr. So, the following code which
clears the buffer is dangerous and can cause crashes, like below :
memset(drvdata->buf, 0, drvdata->size);
Unable to handle kernel paging request at virtual address ffffff800a145000
pgd = ffffffc974726000
*pgd=00000009f3e91003, *pud=00000009f3e91003, *pmd=0000000000000000
PREEMPT SMP
Modules linked in:
CPU: 4 PID: 1692 Comm: dd Not tainted 4.7.0-rc2+ #1721
Hardware name: ARM Juno development board (r0) (DT)
task: ffffffc9734a0080 ti: ffffffc974460000 task.ti: ffffffc974460000
PC is at __memset+0x1ac/0x200
LR is at tmc_read_unprepare_etr+0x144/0x1bc
pc : [<ffffff80083a05ac>] lr : [<ffffff800859c984>] pstate: 200001c5
...
[<ffffff80083a05ac>] __memset+0x1ac/0x200
[<ffffff800859b2e4>] tmc_release+0x90/0x94
[<ffffff8008202f58>] __fput+0xa8/0x1ec
[<ffffff80082030f4>] ____fput+0xc/0x14
[<ffffff80080c3ef8>] task_work_run+0xb0/0xe4
[<ffffff8008088bf4>] do_notify_resume+0x64/0x6c
[<ffffff8008084d5c>] work_pending+0x10/0x14
Code: 91010108 54ffff4a 8b040108 cb050042 (d50b7428)
Since we clear the buffer anyway in the following call to
tmc_etr_enable_hw(), remove the erroneous memset().
Fixes: commit de5461970b3e9e1 ("coresight: tmc: allocating memory when needed")
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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At the end of the trace capture, we free the allocated memory,
resetting the drvdata->buf to NULL, to indicate that trace data
was collected and the next trace session should allocate the
memory in tmc_enable_etr_sink_sysfs.
The tmc_enable_etr_sink_sysfs, we only allocate memory if drvdata->vaddr
is not NULL (which is not performed at the end of previous session).
This can cause, drvdata->vaddr getting assigned NULL and later we do
memset() which causes a crash as below :
Unable to handle kernel NULL pointer dereference at virtual
address 00000000
pgd = ffffffc9747f0000
[00000000] *pgd=00000009f402e003, *pud=00000009f402e003,
*pmd=0000000000000000
Internal error: Oops: 96000046 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 1592 Comm: bash Not tainted 4.7.0-rc1+ #1712
Hardware name: ARM Juno development board (r0) (DT)
task: ffffffc078fe0080 ti: ffffffc974178000 task.ti: ffffffc974178000
PC is at __memset+0x1ac/0x200
LR is at tmc_enable_etr_sink+0xf8/0x304
pc : [<ffffff80083a002c>] lr : [<ffffff800859be44>] pstate: 400001c5
sp : ffffffc97417bc00
x29: ffffffc97417bc00 x28: ffffffc974178000
Call trace:
Exception stack(0xffffffc97417ba40 to 0xffffffc97417bb60)
ba40: 0000000000000001 ffffffc974a5d098 ffffffc97417bc00 ffffff80083a002c
ba60: ffffffc974a5d118 0000000000000000 0000000000000000 0000000000000000
ba80: 0000000000000001 0000000000000000 ffffff800859bdec 0000000000000040
baa0: ffffff8008b45b58 00000000000001c0 ffffffc97417baf0 ffffff80080eddb4
bac0: 0000000000000003 ffffffc078fe0080 ffffffc078fe0960 ffffffc078fe0940
bae0: 0000000000000000 0000000000000000 00000000007fffc0 0000000000000004
bb00: 0000000000000000 0000000000000040 000000000000003f 0000000000000000
bb20: 0000000000000000 0000000000000000 0000000000000000 0000000000000001
bb40: ffffffc078fe0960 0000000000000018 ffffffffffffffff 0008669628000000
[<ffffff80083a002c>] __memset+0x1ac/0x200
[<ffffff8008599814>] coresight_enable_path+0xa8/0x1dc
[<ffffff8008599b10>] coresight_enable+0x88/0x1b8
[<ffffff8008599d88>] enable_source_store+0x3c/0x6c
[<ffffff800845eaf4>] dev_attr_store+0x18/0x28
[<ffffff80082829e8>] sysfs_kf_write+0x54/0x64
[<ffffff8008281c30>] kernfs_fop_write+0x148/0x1d8
[<ffffff8008200128>] __vfs_write+0x28/0x110
[<ffffff8008200e88>] vfs_write+0xa0/0x198
[<ffffff80082021b0>] SyS_write+0x44/0xa0
[<ffffff8008084e70>] el0_svc_naked+0x24/0x28
Code: 91010108 54ffff4a 8b040108 cb050042 (d50b7428)
This patch fixes the issue by clearing the drvdata->vaddr while we free
the allocated buffer at the end of a session, so that we allocate the
memory again.
Cc: mathieu.poirier@linaro.org
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The sysFS and Perf access methods can't be allowed to interfere
with one another. As such introducing guards to access
functions that prevents moving forward if a TMC is already
being used.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Calling tmc_etf/etr_dump_hw() is required only when operating from
sysFS. When working from Perf, the system memory is harvested
from the AUX trace API.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Moving tmc_drvdata::enable to a local_t mode. That way the
sink interface is aware of it's orgin and the foundation for
mutual exclusion between the sysFS and Perf interface can be
laid out.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Allowing multiple readers to access the trace data simultaniously
via sysFS provides no shortage of opportunity for race condition,
mandates two variable to be maintained (drvdata::read_count and
drvdata::reading), makes the code complex and provide little
advantages, if any.
This patch streamlines the read process by restricting trace data
access to a single user. That way drvdata::read_count can
be eliminated and race conditions (along with faulty error handling)
in function tmc_open() and tmc_release() eliminated.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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In it's current form the TMC probe() function allocates
trace buffer memory at boot time, event if coresight isn't
used. This is highly inefficient since trace buffers can
occupy a lot of memory that could be used otherwised.
This patch allocates trace buffers on the fly, when the
coresight subsystem is solicited. Allocated buffers are
released when traces are read using the device descriptors
under /dev.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Dealing with HW related matters in tmc_read_prepare/unprepare
becomes convoluted when many cases need to be handled distinctively.
As such moving processing related to HW setup to individual driver
files and keep the core driver generic.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The TMC block can operate in 3 modes (ETB, ETF and ETR) and accessed
via two interfaces (sysFS and Perf). That makes 6 mode to cover, which
is way too much coupling for a single file.
This patch splits the original TMC driver in 2 halves, one for ETB/ETF
and another one for ETR mode. A common core is kept for functionality
common to all 3 modes.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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