- 24 May, 2008 11 commits
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Pekka Paalanen authored
another weekend, another patch. This should apply on top of my previous patch from March 23rd. Summary of changes: - Print PCI device list in output header - work around recursive probe hits on SMP - refactor dis/arm_kmmio_fault_page() and add check for page levels - remove un/reference_kmmio(), the die notifier hook is registered permanently into the list - explicitly check for single stepping in die notifier callback I have tested this version on my UP Athlon64 desktop with Nouveau, and SMP Core 2 Duo laptop with the proprietary nvidia driver. Both systems are 64-bit. One previously unknown bug crept into daylight: the ftrace framework's output routines print the first entry last after buffer has wrapped around. The most important regressions compared to non-ftrace mmiotrace at this time are: - failure of trace_pipe file - illegal lines in output file - unaware of losing data due to buffer full Personally I'd like to see these three solved before submitting to mainline. Other issues may come up once we know when we lose events. Signed-off-by:
Pekka Paalanen <pq@iki.fi> Signed-off-by:
Ingo Molnar <mingo@elte.hu> Signed-off-by:
Thomas Gleixner <tglx@linutronix.de>
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Pekka Paalanen authored
here is a patch that makes mmiotrace work almost well within the tracing framework. The patch applies on top of my previous patch. I have my own output formatting in place now. Summary of changes: - fix the NULL dereference that was due to not calling tracing_reset() - add print_line() callback into struct tracer - implement print_line() for mmiotrace, producing up-to-spec text - add my output header, but that is not really called in the right place - rewrote the main structs in mmiotrace - added two new trace entry types: TRACE_MMIO_RW and TRACE_MMIO_MAP - made some functions in trace.c non-static - check current==NULL in tracing_generic_entry_update() - fix(?) comparison in trace_seq_printf() Things seem to work fine except a few issues. Markers (text lines injected into mmiotrace log) are missing, I did not feel hacking them in before we have variable length entries. My output header is printed only for 'trace' file, but not 'trace_pipe'. For some reason, despite my quick fix, iter->trace is NULL in print_trace_line() when called from 'trace_pipe' file, which means I don't get proper output formatting. I only tried by loading nouveau.ko, which just detects the card, and that is traced fine. I didn't try further. Map, two reads and unmap. Works perfectly. I am missing the information about overflows, I'd prefer to have a counter for lost events. I didn't try, but I guess currently there is no way of knowning when it overflows? So, not too far from being fully operational, it seems :-) And looking at the diffstat, there also is some 700-900 lines of user space code that just became obsolete. Signed-off-by:
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Pekka Paalanen authored
On Sat, 22 Mar 2008 13:07:47 +0100 Ingo Molnar <mingo@elte.hu> wrote: > > > i'd suggest the following: pull x86.git and sched-devel.git into a > > > single tree [the two will combine without rejects]. Then try to add a > > > kernel/tracing/trace_mmiotrace.c ftrace plugin. The trace_sysprof.c > > > plugin might be a good example. > > > > I did this and now I have mmiotrace enabled/disabled via the tracing > > framework (what do we call this, since ftrace is one of the tracers?). > > cool! could you send the patches for that? (even if they are not fully > functional yet) Patch attached in the end. Nice to see how much code disappeared. I tried to mark all the features I had to break with XXX-comments. Signed-off-by:
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Pekka Paalanen authored
Kconfig.debug, Makefile and testmmiotrace.c style fixes. Use real mutex instead of mutex. Fix failure path in register probe func. kmmio: RCU read-locked over single stepping. Generate mapping id's. Make mmio-mod.c built-in and rewrite its locking. Add debugfs file to enable/disable mmiotracing. kmmio: use irqsave spinlocks. Lots of cleanups in mmio-mod.c Marker file moved from /proc into debugfs. Call mmiotrace entrypoints directly from ioremap.c. Signed-off-by:
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Pekka Paalanen authored
kmmio.c handles the list of mmio probes with callbacks, list of traced pages, and attaching into the page fault handler and die notifier. It arms, traps and disarms the given pages, this is the core of mmiotrace. mmio-mod.c is a user interface, hooking into ioremap functions and registering the mmio probes. It also decodes the required information from trapped mmio accesses via the pre and post callbacks in each probe. Currently, hooking into ioremap functions works by redefining the symbols of the target (binary) kernel module, so that it calls the traced versions of the functions. The most notable changes done since the last discussion are: - kmmio.c is a built-in, not part of the module - direct call from fault.c to kmmio.c, removing all dynamic hooks - prepare for unregistering probes at any time - make kmmio re-initializable and accessible to more than one user - rewrite kmmio locking to remove all spinlocks from page fault path Can I abuse call_rcu() like I do in kmmio.c:unregister_kmmio_probe() or is there a better way? The function called via call_rcu() itself calls call_rcu() again, will this work or break? There I need a second grace period for RCU after the first grace period for page faults. Mmiotrace itself (mmio-mod.c) is still a module, I am going to attack that next. At some point I will start looking into how to make mmiotrace a tracer component of ftrace (thanks for the hint, Ingo). Ftrace should make the user space part of mmiotracing as simple as 'cat /debug/trace/mmio > dump.txt'. Signed-off-by:
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Pekka Paalanen authored
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Pekka Paalanen authored
The custom page fault handler list is replaced with a single function pointer. All related functions and variables are renamed for mmiotrace. Signed-off-by:
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Pekka Paalanen authored
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Pekka Paalanen authored
Relay has per-cpu buffers, but mmiotrace was using only a single flag for detecting buffer full/not-full transitions. The new code makes this per-cpu and actually counts missed events. Signed-off-by:
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Pekka Paalanen authored
Use lookup_address() from pageattr.c instead of doing the same manually. Also had to EXPORT_SYMBOL_GPL(lookup_address) to make this work for modules. This also fixes "undefined symbol 'init_mm'" compile error for x86_32. Signed-off-by:
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Pekka Paalanen authored
Mmiotrace is a tool for trapping memory mapped IO (MMIO) accesses within the kernel. It is used for debugging and especially for reverse engineering evil binary drivers. Mmiotrace works by wrapping the ioremap family of kernel functions and marking the returned pages as not present. Access to the IO memory triggers a page fault, which will be handled by mmiotrace's custom page fault handler. This will single-step the faulted instruction with the MMIO page marked as present. Access logs are directed to user space via relay and debug_fs. This page fault approach is necessary, because binary drivers have readl/writel etc. calls inlined and therefore extremely difficult to trap with with e.g. kprobes. This patch depends on the custom page fault handlers patch. Signed-off-by:
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- 23 May, 2008 29 commits
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Steven Rostedt authored
Now that ftrace is being ported to other architectures, it has become apparent that DYNAMIC_FTRACE is dependent on whether or not that architecture implements dynamic ftrace. FTRACE itself may be ported to an architecture without porting dynamic ftrace. This patch adds HAVE_DYNAMIC_FTRACE to allow architectures to port ftrace without having to also port the dynamic aspect as well. Signed-off-by:
Steven Rostedt <srostedt@redhat.com> Signed-off-by:
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Steven Rostedt authored
This patch removes the Makefile turd and uses the nice CFLAGS_REMOVE macro in the x86/kernel directory. Signed-off-by:
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Steven Rostedt authored
This patch removes the Makefile turd and uses the nice CFLAGS_REMOVE macro in the lib directory. Signed-off-by:
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Steven Rostedt authored
This patch removes the Makefile turd and uses the nice CFLAGS_REMOVE macro in the kernel directory. Signed-off-by:
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Steven Rostedt authored
We currently have a way to add special CFLAGS to code, but we do not have a way to remove them if needed. With the case of ftrace, some files should simply not be profiled. Adding the -pg flag to these files is simply a waste, and adding "notrace" to each and every function is ugly. Currently we put in "Makefile turd" [1] to stop the compiler from adding -pg to certain files. This was clumsy and awkward. This patch now adds the revese of CFLAGS_(basename).o with CFLAGS_REMOVE_(basename).o. This allows developers to prevent certain CFLAGS from being used to compile files. For example, we can now do CFLAGS_REMOVE_string.o = -pg to remove the -pg option from the string.o file in the lib directory. Note: a space delimited list of options may be added to the REMOVE macro. [1] - what David Miller called the workaronud to remove -pg Signed-off-by:
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Steven Rostedt authored
This patch adds full support for ftrace for PowerPC (both 64 and 32 bit). This includes dynamic tracing and function filtering. Signed-off-by:
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Steven Rostedt authored
PPC doesn't have the irqs_disabled_flags needed by ftrace. This patch adds it. Signed-off-by:
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Ingo Molnar authored
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Ingo Molnar authored
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Ingo Molnar authored
factor out code and clean it up. Signed-off-by:
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Ingo Molnar authored
David S. Miller noticed the following bug: the -pg instrumentation function callback is named differently on each platform. On x86 it is mcount, on sparc it is _mcount. So the export does not make sense in kernel/trace/ftrace.c - move it to x86. Signed-off-by:
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David Miller authored
Signed-off-by:
David S. Miller <davem@davemloft.net> Signed-off-by:
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David Miller authored
It causes unaligned access traps on platforms like sparc (ftrace_page may be marked packed, but once we return a dyn_ftrace sub-object from this array to another piece of code, the "packed" part of the typing information doesn't propagate). But also, it didn't serve any purpose either. Even if packed, on 64-bit or 32-bit, it didn't give us any more dyn_ftrace entries per-page. Signed-off-by:
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Ingo Molnar authored
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Mathieu Desnoyers authored
Porting ftrace to the marker infrastructure. Don't need to chain to the wakeup tracer from the sched tracer, because markers support multiple probes connected. Signed-off-by:
Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> CC: Steven Rostedt <rostedt@goodmis.org> Signed-off-by:
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Mathieu Desnoyers authored
To support the forthcoming "immediate values" marker optimization, we must have a way to declare markers in few code paths that does not use instruction modification based enable. This will be the case of printk(), some traps and eventually lockdep instrumentation. Changelog : - Fix reversed boolean logic of "generic". Signed-off-by:
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Mathieu Desnoyers authored
Denys Vlasenko <vda.linux@googlemail.com> : > Not in this patch, but I noticed: > > #define __trace_mark(name, call_private, format, args...) \ > do { \ > static const char __mstrtab_##name[] \ > __attribute__((section("__markers_strings"))) \ > = #name "\0" format; \ > static struct marker __mark_##name \ > __attribute__((section("__markers"), aligned(8))) = \ > { __mstrtab_##name, &__mstrtab_##name[sizeof(#name)], \ > 0, 0, marker_probe_cb, \ > { __mark_empty_function, NULL}, NULL }; \ > __mark_check_format(format, ## args); \ > if (unlikely(__mark_##name.state)) { \ > (*__mark_##name.call) \ > (&__mark_##name, call_private, \ > format, ## args); \ > } \ > } while (0) > > In this call: > > (*__mark_##name.call) \ > (&__mark_##name, call_private, \ > format, ## args); \ > > you make gcc allocate duplicate format string. You can use > &__mstrtab_##name[sizeof(#name)] instead since it holds the same string, > or drop ", format," above and "const char *fmt" from here: > > void (*call)(const struct marker *mdata, /* Probe wrapper */ > void *call_private, const char *fmt, ...); > > since mdata->format is the same and all callees which need it can take it there. Very good point. I actually thought about dropping it, since it would remove an unnecessary argument from the stack. And actually, since I now have the marker_probe_cb sitting between the marker site and the callbacks, there is no API change required. Thanks :) Mathieu Signed-off-by: -
Steven Rostedt authored
Currently there is no protection from the root user to use up all of memory for trace buffers. If the root user allocates too many entries, the OOM killer might start kill off all tasks. This patch adds an algorith to check the following condition: pages_requested > (freeable_memory + current_trace_buffer_pages) / 4 If the above is met then the allocation fails. The above prevents more than 1/4th of freeable memory from being used by trace buffers. To determine the freeable_memory, I made determine_dirtyable_memory in mm/page-writeback.c global. Special thanks goes to Peter Zijlstra for suggesting the above calculation. Signed-off-by:
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Pekka Paalanen authored
Refactor code from tracing_read_pipe() and create trace_seq_to_user(). Moved trace_seq_reset() call before iter->trace->read() call so that when all leftover data is returned, trace_seq is reset automatically. Signed-off-by:
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Steven Rostedt authored
Due to debug hooks in the kernel that can change the way smp_processor_id works, use raw_smp_processor_id in mcount called functions (namely ftrace_record_ip). Currently we annotate most debug functions from calling mcount, but we should not rely on that to prevent kernel lockups. This patch uses the raw_smp_processor_id to prevent a recusive crash that can happen if a debug hook in smp_processor_id calls mcount. Signed-off-by:
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Ingo Molnar authored
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Ingo Molnar authored
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Steven Rostedt authored
In resetting the iterator in read_pipe, the reset of pos was postitioned in the wrong location with respect to the memset operation. The current code sets pos, incorrectly, to zero. Signed-off-by:
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Pekka Paalanen authored
text_poke is sleepable. The original fix by Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>. Signed-off-by:
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Steven Rostedt authored
This patch adds a method for open_pipe and open_read to the pluggins so that they can add a header to the trace pipe call. Signed-off-by:
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Steven Rostedt authored
This patch sets up the infrastructure to record overruns of the tracing buffer. Signed-off-by:
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Pekka Paalanen authored
Without CONFIG_DYNAMIC_FTRACE, mark_rodata_ro() would mark a wrong number of pages as no-execute. The bug was introduced in the patch "ftrace: dont write protect kernel text". The symptom was machine reboot after a CPU hotplug. Signed-off-by:
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Steven Rostedt authored
In cleaning up of the sched_switch code, the function trace recording of task comms was removed. This patch adds back the recording of comms for function trace. The output of ftrace now has the task comm instead of <...>. Signed-off-by:
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Steven Rostedt authored
This is first installment of adding documentation to the ftrace. Expect many more patches of this kind in the near future. Signed-off-by:
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