Impact: fix crash

In case of losing samples struct op_entry could have been used
uninitialized causing e.g. a wrong preemption count or NULL pointer
access. This patch fixes this.
Signed-off-by: NRobert Richter <robert.richter@amd.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This patch creates the new functions

 oprofile_write_reserve()
 oprofile_add_data()
 oprofile_write_commit()

and makes them part of the oprofile api.
Signed-off-by: NRobert Richter <robert.richter@amd.com>

The ifdefs can be removed since the code is no longer ibs specific and
can be used for other purposes as well. IBS specific code is only in
op_model_amd.c.
Signed-off-by: NRobert Richter <robert.richter@amd.com>

The new ring buffer implementation allows the storage of samples with
different size. This patch implements the usage of the new sample
format to store ibs samples in the cpu buffer. Until now, writing to
the cpu buffer could lead to incomplete sampling sequences since IBS
samples were transfered in multiple samples. Due to a full buffer,
data could be lost at any time. This can't happen any more since the
complete data is reserved in advance and then stored in a single
sample.
Signed-off-by: NRobert Richter <robert.richter@amd.com>

This function can be used to attach data to a sample. It returns the
remaining free buffer size that has been reserved with
op_cpu_buffer_write_reserve().
Signed-off-by: NRobert Richter <robert.richter@amd.com>

Special events such as task or context switches are marked with an
escape code in the cpu buffer followed by an event code or a task
identifier. There is one escape code per event. To make escape
sequences also available for data samples the internal cpu buffer
format must be changed. The current implementation does not allow the
extension of event codes since this would lead to collisions with the
task identifiers. To avoid this, this patch introduces an event mask
that allows the storage of multiple events with one escape code. Now,
task identifiers are stored in the data section of the sample. The
implementation also allows the usage of custom data in a sample. As a
side effect the new code is much more readable and easier to
understand.
Signed-off-by: NRobert Richter <robert.richter@amd.com>

This implements the support of samples with attached data.
Signed-off-by: NRobert Richter <robert.richter@amd.com>

This function prepares the cpu buffer to write a sample.

Struct op_entry is used during operations on the ring buffer while
struct op_sample contains the data that is stored in the ring
buffer. Struct entry can be uninitialized. The function reserves a
data array that is specified by size. Use op_cpu_buffer_write_commit()
after preparing the sample. In case of errors a null pointer is
returned, otherwise the pointer to the sample.
Signed-off-by: NRobert Richter <robert.richter@amd.com>

Rename the fucntion to op_add_sample() since there is a collision with
another one with the same name in buffer_sync.c.
Signed-off-by: NRobert Richter <robert.richter@amd.com>

This code is broken since a TRACE_BEGIN_CODE is never sent to the
daemon. The data becomes corrupt since the backtrace is interpreted as
ibs sample.
Signed-off-by: NRobert Richter <robert.richter@amd.com>

Signed-off-by: NRobert Richter <robert.richter@amd.com>

Signed-off-by: NRobert Richter <robert.richter@amd.com>

Signed-off-by: NRobert Richter <robert.richter@amd.com>

This patch removes the unused return parameter in
oprofile_begin_trace(). Also, oprofile_begin_trace() and
oprofile_end_trace() are inline now.
Signed-off-by: NRobert Richter <robert.richter@amd.com>

This patch adds the inline function __oprofile_add_ext_sample() to
cpu_buffer.c and thus reduces overhead when calling
oprofile_add_sample().
Signed-off-by: NRobert Richter <robert.richter@amd.com>

Reordering code to keep alloc/free functions together.
Signed-off-by: NRobert Richter <robert.richter@amd.com>

This patch moves ring buffer inline functions to cpu_buffer.c.

Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NRobert Richter <robert.richter@amd.com>

This patch renames cpu buffer functions to something more oprofile
specific names. Functions will be moved to the global name space.

Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NRobert Richter <robert.richter@amd.com>

This patch renames kernel-wide identifiers to something more oprofile
specific names.

Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NRobert Richter <robert.richter@amd.com>

The number of lost samples could be greater than the number of
received samples. This patches fixes this. The implementation
introduces return values for add_sample() and add_code().
Signed-off-by: NRobert Richter <robert.richter@amd.com>

This function is no longer available after the port to the new ring
buffer. Its removal can lead to incomplete sampling sequences since
IBS samples and backtraces are transfered in multiple samples. Due to
a full buffer, samples could be lost any time. The userspace daemon
has to live with such incomplete sampling sequences as long as the
data within one sample is consistent.

This will be fixed by changing the internal buffer data there all data
of one IBS sample or a backtrace is packed in a single ring buffer
entry. This is possible since the new ring buffer supports variable
data size.
Signed-off-by: NRobert Richter <robert.richter@amd.com>

This patch replaces the current oprofile cpu buffer implementation
with the ring buffer provided by the tracing framework. The motivation
here is to leave the pain of implementing ring buffers to others. Oh,
no, there are more advantages. Main reason is the support of different
sample sizes that could be stored in the buffer. Use cases for this
are IBS and Cell spu profiling. Using the new ring buffer ensures
valid and complete samples and allows copying the cpu buffer stateless
without knowing its content. Second it will use generic kernel API and
also reduce code size. And hopefully, there are less bugs.

Since the new tracing ring buffer implementation uses spin locks to
protect the buffer during read/write access, it is difficult to use
the buffer in an NMI handler. In this case, writing to the buffer by
the NMI handler (x86) could occur also during critical sections when
reading the buffer. To avoid this, there are 2 buffers for independent
read and write access. Read access is in process context only, write
access only in the NMI handler. If the read buffer runs empty, both
buffers are swapped atomically. There is potentially a small window
during swapping where the buffers are disabled and samples could be
lost.

Using 2 buffers is a little bit overhead, but the solution is clear
and does not require changes in the ring buffer implementation. It can
be changed to a single buffer solution when the ring buffer access is
implemented as non-locking atomic code.

The new buffer requires more size to store the same amount of samples
because each sample includes an u32 header. Also, there is more code
to execute for buffer access. Nonetheless, the buffer implementation
is proven in the ftrace environment and worth to use also in oprofile.

Patches that changes the internal IBS buffer usage will follow.

Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: NRobert Richter <robert.richter@amd.com>

This is in preparation for changes in the cpu buffer implementation.
Signed-off-by: NRobert Richter <robert.richter@amd.com>

This is in preparation for changes in the cpu buffer implementation.
Signed-off-by: NRobert Richter <robert.richter@amd.com>

This is in preparation for changes in the cpu buffer implementation.
Signed-off-by: NRobert Richter <robert.richter@amd.com>

Signed-off-by: NRobert Richter <robert.richter@amd.com>

This fixes the coding style of some comments.
Signed-off-by: NRobert Richter <robert.richter@amd.com>

The issue is the SPU code is not holding the kernel mutex lock while
adding samples to the kernel buffer.

This patch creates per SPU buffers to hold the data.  Data
is added to the buffers from in interrupt context.  The data
is periodically pushed to the kernel buffer via a new Oprofile
function oprofile_put_buff(). The oprofile_put_buff() function
is called via a work queue enabling the funtion to acquire the
mutex lock.

The existing user controls for adjusting the per CPU buffer
size is used to control the size of the per SPU buffers.
Similarly, overflows of the SPU buffers are reported by
incrementing the per CPU buffer stats.  This eliminates the
need to have architecture specific controls for the per SPU
buffers which is not acceptable to the OProfile user tool
maintainer.

The export of the oprofile add_event_entry() is removed as it
is no longer needed given this patch.

Note, this patch has not addressed the issue of indexing arrays
by the spu number.  This still needs to be fixed as the spu
numbering is not guarenteed to be 0 to max_num_spus-1.
Signed-off-by: NCarl Love <carll@us.ibm.com>
Signed-off-by: NMaynard Johnson <maynardj@us.ibm.com>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NAcked-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

This patch addresses problems when hotplugging cpus while
profiling. Instead of allocating only online cpus, all possible cpu
buffers are allocated, which allows cpus to be onlined during
operation. If a cpu is offlined before profiling is shutdown
wq_sync_buffer checks for this condition then cancels this work and
does not sync this buffer.
Signed-off-by: NChris J Arges <arges@linux.vnet.ibm.com>
Signed-off-by: NRobert Richter <robert.richter@amd.com>

Signed-off-by: NRobert Richter <robert.richter@amd.com>

Signed-off-by: NRobert Richter <robert.richter@amd.com>

Code looks much more cleaner now.
Signed-off-by: NRobert Richter <robert.richter@amd.com>

If an error occurs on opcontrol start, the event and per cpu buffers
are released.  If later opcontrol shutdown is called then the free
function will be called again to free buffers that no longer
exist.  This results in a kernel oops.  The following changes
prevent the call to delete buffers that don't exist.
Signed-off-by: NCarl Love <carll@us.ibm.com>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NRobert Richter <robert.richter@amd.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Signed-off-by: NRobert Richter <robert.richter@amd.com>
Cc: oprofile-list <oprofile-list@lists.sourceforge.net>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Barry Kasindorf <barry.kasindorf@amd.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NRobert Richter <robert.richter@amd.com>
Cc: oprofile-list <oprofile-list@lists.sourceforge.net>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Barry Kasindorf <barry.kasindorf@amd.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This patchset supports the new profiling hardware available in the
latest AMD CPUs in the oProfile driver.
Signed-off-by: NBarry Kasindorf <barry.kasindorf@amd.com>
Signed-off-by: NRobert Richter <robert.richter@amd.com>
Cc: oprofile-list <oprofile-list@lists.sourceforge.net>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Alignment was previously requested because cpu_buffer was an [NR_CPUS]
array, to avoid cache line sharing between CPUS.

After commit 608dfddd (oprofile: change
cpu_buffer from array to per_cpu variable ), we dont need to force an
alignement anymore since cpu_buffer sits in per_cpu zone.
Signed-off-by: NEric Dumazet <dada1@cosmosbay.com>
Cc: Mike Travis <travis@sgi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Change cpu_buffer from array to per_cpu variable in oprofile functions.

[akpm@linux-foundation.org: coding-style fixes]
Cc: Philippe Elie <phil.el@wanadoo.fr>
Signed-off-by: NMike Travis <travis@sgi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Instruction pointer returned by profile_pc() can be a random value.  This
break the assumption than we can safely set struct op_sample.eip field to a
magic value to signal to the per-cpu buffer reader side special event like
task switch ending up in a segfault in get_task_mm() when profile_pc()
return ~0UL.  Fixed by sanitizing the sampled eip and reject/log invalid
eip.

Problem reported by Sami Farin, patch tested by him.
Signed-off-by: NPhilippe Elie <phil.el@wanadoo.fr>
Tested-by: NSami Farin <safari-kernel@safari.iki.fi>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix up for make allyesconfig.
Signed-Off-By: NDavid Howells <dhowells@redhat.com>