For using trace_seq_*() functions in NMI context, I posted a patch to move
it to the lib/ directory. This caused Andrew Morton to take a look at the code.
He went through and gave a lot of comments about missing kernel doc,
inconsistent types for the save variable, mix match of EXPORT_SYMBOL_GPL()
and EXPORT_SYMBOL() as well as missing EXPORT_SYMBOL*()s. There were
a few comments about the way variables were being compared (int vs uint).
All these were good review comments and should be implemented regardless of
if trace_seq.c should be moved to lib/ or not.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The trace_seq_*() functions are a nice utility that allows users to manipulate
buffers with printf() like formats. It has its own trace_seq.h header in
include/linux and should be in its own file. Being tied with trace_output.c
is rather awkward.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Strings should be copied with strlcpy instead of strncpy when they will
later be printed via %s. This guarantees that they terminate with a
NUL '\0' character and do not run pass the end of the allocated string.
This is only for sample code, but it should stil represent a good
role model.
Link: http://lkml.kernel.org/p/51C2E204.1080501@huawei.com
Signed-off-by: Zhao Hongjiang <zhaohongjiang@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The enabled_functions is used to help debug the dynamic function tracing.
Adding what trampolines are attached to files is useful for debugging.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Function graph tracing is a bit different than the function tracers, as
it is processed after either the ftrace_caller or ftrace_regs_caller
and we only have one place to modify the jump to ftrace_graph_caller,
the jump needs to happen after the restore of registeres.
The function graph tracer is dependent on the function tracer, where
even if the function graph tracing is going on by itself, the save and
restore of registers is still done for function tracing regardless of
if function tracing is happening, before it calls the function graph
code.
If there's no function tracing happening, it is possible to just call
the function graph tracer directly, and avoid the wasted effort to save
and restore regs for function tracing.
This requires adding new flags to the dyn_ftrace records:
FTRACE_FL_TRAMP
FTRACE_FL_TRAMP_EN
The first is set if the count for the record is one, and the ftrace_ops
associated to that record has its own trampoline. That way the mcount code
can call that trampoline directly.
In the future, trampolines can be added to arbitrary ftrace_ops, where you
can have two or more ftrace_ops registered to ftrace (like kprobes and perf)
and if they are not tracing the same functions, then instead of doing a
loop to check all registered ftrace_ops against their hashes, just call the
ftrace_ops trampoline directly, which would call the registered ftrace_ops
function directly.
Without this patch perf showed:
0.05% hackbench [kernel.kallsyms] [k] ftrace_caller
0.05% hackbench [kernel.kallsyms] [k] arch_local_irq_save
0.05% hackbench [kernel.kallsyms] [k] native_sched_clock
0.04% hackbench [kernel.kallsyms] [k] __buffer_unlock_commit
0.04% hackbench [kernel.kallsyms] [k] preempt_trace
0.04% hackbench [kernel.kallsyms] [k] prepare_ftrace_return
0.04% hackbench [kernel.kallsyms] [k] __this_cpu_preempt_check
0.04% hackbench [kernel.kallsyms] [k] ftrace_graph_caller
See that the ftrace_caller took up more time than the ftrace_graph_caller
did.
With this patch:
0.05% hackbench [kernel.kallsyms] [k] __buffer_unlock_commit
0.04% hackbench [kernel.kallsyms] [k] call_filter_check_discard
0.04% hackbench [kernel.kallsyms] [k] ftrace_graph_caller
0.04% hackbench [kernel.kallsyms] [k] sched_clock
The ftrace_caller is no where to be found and ftrace_graph_caller still
takes up the same percentage.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The ftrace dynamic record has a flags element that also has a counter.
Instead of hard coding "rec->flags & ~FTRACE_FL_MASK" all over the
place. Use a macro instead.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
As new flags will be added to the ftrace dynamic record, and since
the flags field is also a counter, converting the numbers used to
do the shifting and masking into a set of macros where we only need
to deal with the max bit count of the counter and the number of bits
for the flags will prevent mistakes in the future.
Dealing with only two numbers is much easier than updating all the
macros that deal with shifting and masking.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When registering a function callback for the function tracer, the ops
can specify if it wants to save full regs (like an interrupt would)
for each function that it traces, or if it does not care about regs
and just wants to have the fastest return possible.
Once a ops has registered a function, if other ops register that
function they all will receive the regs too. That's because it does
the work once, it does it for everyone.
Now if the ops wanting regs unregisters the function so that there's
only ops left that do not care about regs, those ops will still
continue getting regs and going through the work for it on that
function. This is because the disabling of the rec counter only
sees the ops registered, and does not see the ops that are still
attached, and does not know if the current ops that are still attached
want regs or not. To play it safe, it just keeps regs being processed
until no function is registered anymore.
Instead of doing that, check the ops that are still registered for that
function and if none want regs for it anymore, then disable the
processing of regs.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Pull ARM fixes from Russell King:
"Another round of ARM fixes. The largest change here is the L2 changes
to work around problems for the Armada 37x/380 devices, where most of
the size comes down to comments rather than code.
The other significant fix here is for the ptrace code, to ensure that
rewritten syscalls work as intended. This was pointed out by Kees
Cook, but Will Deacon reworked the patch to be more elegant.
The remainder are fairly trivial changes"
* 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
ARM: 8087/1: ptrace: reload syscall number after secure_computing() check
ARM: 8086/1: Set memblock limit for nommu
ARM: 8085/1: sa1100: collie: add top boot mtd partition
ARM: 8084/1: sa1100: collie: revert back to cfi_probe
ARM: 8080/1: mcpm.h: remove unused variable declaration
ARM: 8076/1: mm: add support for HW coherent systems in PL310 cache
Note that I don't maintain Documentation/ABI/,
Documentation/devicetree/, or the language translation files.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On the syscall tracing path, we call out to secure_computing() to allow
seccomp to check the syscall number being attempted. As part of this, a
SIGTRAP may be sent to the tracer and the syscall could be re-written by
a subsequent SET_SYSCALL ptrace request. Unfortunately, this new syscall
is ignored by the current code unless TIF_SYSCALL_TRACE is also set on
the current thread.
This patch slightly reworks the enter path of the syscall tracing code
so that we always reload the syscall number from
current_thread_info()->syscall after the potential ptrace traps.
Acked-by: Kees Cook <keescook@chromium.org>
Tested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Commit 1c2f87c (ARM: 8025/1: Get rid of meminfo) changed find_limits
to use memblock_get_current_limit for calculating the max_low pfn.
nommu targets never actually set a limit on memblock though which
means memblock_get_current_limit will just return the default
value. Set the memblock_limit to be the end of DDR to make sure
bounds are calculated correctly.
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The CFI mapping is now perfect so we can expose the top block, read only.
There isn't much to read, though, just the sharpsl_params values.
Signed-off-by: Andrea Adami <andrea.adami@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Reverts commit d26b17edaf
ARM: sa1100: collie.c: fall back to jedec_probe flash detection
Unfortunately the detection was challenged on the defective unit used for tests:
one of the NOR chips did not respond to the CFI query.
Moreover that bad device needed extra delays on erase-suspend/resume cycles.
Tested personally on 3 different units and with feedback of two other users.
Signed-off-by: Andrea Adami <andrea.adami@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The sync_phys variable has been replaced by link time computation in
mcpm_head.S before the code was submitted upstream.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
When a PL310 cache is used on a system that provides hardware
coherency, the outer cache sync operation is useless, and can be
skipped. Moreover, on some systems, it is harmful as it causes
deadlocks between the Marvell coherency mechanism, the Marvell PCIe
controller and the Cortex-A9.
To avoid this, this commit introduces a new Device Tree property
'arm,io-coherent' for the L2 cache controller node, valid only for the
PL310 cache. It identifies the usage of the PL310 cache in an I/O
coherent configuration. Internally, it makes the driver disable the
outer cache sync operation.
Note that technically speaking, a fully coherent system wouldn't
require any of the other .outer_cache operations. However, in
practice, when booting secondary CPUs, these are not yet coherent, and
therefore a set of cache maintenance operations are necessary at this
point. This explains why we keep the other .outer_cache operations and
only ->sync is disabled.
While in theory any write to a PL310 register could cause the
deadlock, in practice, disabling ->sync is sufficient to workaround
the deadlock, since the other cache maintenance operations are only
used in very specific situations.
Contrary to previous versions of this patch, this new version does not
simply NULL-ify the ->sync member, because the l2c_init_data
structures are now 'const' and therefore cannot be modified, which is
a good thing. Therefore, this patch introduces a separate
l2c_init_data instance, called of_l2c310_coherent_data.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Pull spi fixes from Mark Brown:
"A few driver specific fixes, the biggest one being a fix for the newly
added Qualcomm SPI controller driver to make it not use its internal
chip select due to hardware bugs, replacing it with GPIOs"
* tag 'spi-v3.16-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi:
spi: qup: Remove chip select function
spi: qup: Fix order of spi_register_master
spi: sh-sci: fix use-after-free in sh_sci_spi_remove()
spi/pxa2xx: fix incorrect SW mode chipselect setting for BayTrail LPSS SPI
Pull regulator fixes from Mark Brown:
"Several driver specific fixes here, the palmas fixes being especially
important for a range of boards - the recent updates to support new
devices have introduced several regressions"
* tag 'regulator-v3.16-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator:
regulator: tps65218: Correct the the config register for LDO1
regulator: tps65218: Add the missing of_node assignment in probe
regulator: palmas: fix typo in enable_reg calculation
regulator: bcm590xx: fix vbus name
regulator: palmas: Fix SMPS enable/disable/is_enabled
Pull SCSI target fixes from Nicholas Bellinger:
"Mostly minor fixes this time around. The highlights include:
- iscsi-target CHAP authentication fixes to enforce explicit key
values (Tejas Vaykole + rahul.rane)
- fix a long-standing OOPs in target-core when a alua configfs
attribute is accessed after port symlink has been removed.
(Sebastian Herbszt)
- fix a v3.10.y iscsi-target regression causing the login reject
status class/detail to be ignored (Christoph Vu-Brugier)
- fix a v3.10.y iscsi-target regression to avoid rejecting an
existing ITT during Data-Out when data-direction is wrong (Santosh
Kulkarni + Arshad Hussain)
- fix a iscsi-target related shutdown deadlock on UP kernels (Mikulas
Patocka)
- fix a v3.16-rc1 build issue with vhost-scsi + !CONFIG_NET (MST)"
* git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending:
iscsi-target: fix iscsit_del_np deadlock on unload
iovec: move memcpy_from/toiovecend to lib/iovec.c
iscsi-target: Avoid rejecting incorrect ITT for Data-Out
tcm_loop: Fix memory leak in tcm_loop_submission_work error path
iscsi-target: Explicily clear login response PDU in exception path
target: Fix left-over se_lun->lun_sep pointer OOPs
iscsi-target; Enforce 1024 byte maximum for CHAP_C key value
iscsi-target: Convert chap_server_compute_md5 to use kstrtoul
On uniprocessor preemptible kernel, target core deadlocks on unload. The
following events happen:
* iscsit_del_np is called
* it calls send_sig(SIGINT, np->np_thread, 1);
* the scheduler switches to the np_thread
* the np_thread is woken up, it sees that kthread_should_stop() returns
false, so it doesn't terminate
* the np_thread clears signals with flush_signals(current); and goes back
to sleep in iscsit_accept_np
* the scheduler switches back to iscsit_del_np
* iscsit_del_np calls kthread_stop(np->np_thread);
* the np_thread is waiting in iscsit_accept_np and it doesn't respond to
kthread_stop
The deadlock could be resolved if the administrator sends SIGINT signal to
the np_thread with killall -INT iscsi_np
The reproducible deadlock was introduced in commit
db6077fd0b, but the thread-stopping code was
racy even before.
This patch fixes the problem. Using kthread_should_stop to stop the
np_thread is unreliable, so we test np_thread_state instead. If
np_thread_state equals ISCSI_NP_THREAD_SHUTDOWN, the thread exits.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Steven Rostedt (Red Hat)
Masami Hiramatsu
Zhao Hongjiang
Linus Torvalds
Randy Dunlap
Dan Carpenter
Will Deacon
Laura Abbott
Andrea Adami
Nicolas Pitre
Thomas Petazzoni
Mark Brown
Mikulas Patocka