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* powerpc/ftrace: Separate the heuristics for checking call sitesMichael Ellerman2016-07-211-17/+18
| | | | | | | | | | | | | | | | | | | | | | | In __ftrace_make_nop() (the 64-bit version), we have code to deal with two ftrace ABIs. There is the original ABI, which looks mostly like a function call, and then the mprofile-kernel ABI which is just a branch. The code tries to handle both cases, by looking for the presence of a load to restore the TOC pointer (PPC_INST_LD_TOC). If we detect the TOC load, we assume the call site is for an mcount() call using the old ABI. That means we patch the mcount() call with a b +8, to branch over the TOC load. However if the kernel was built with mprofile-kernel, then there will never be a call site using the original ftrace ABI. If for some reason we do see a TOC load, then it's there for a good reason, and we should not jump over it. So split the code, using the existing CC_USING_MPROFILE_KERNEL. Kernels built with mprofile-kernel will only look for, and expect, the new ABI, and similarly for the original ABI. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* powerpc: Define and use PPC64_ELF_ABI_v2/v1Michael Ellerman2016-06-141-2/+2
| | | | | | | | | | | | | | | | We're approaching 20 locations where we need to check for ELF ABI v2. That's fine, except the logic is a bit awkward, because we have to check that _CALL_ELF is defined and then what its value is. So check it once in asm/types.h and define PPC64_ELF_ABI_v2 when ELF ABI v2 is detected. We also have a few places where what we're really trying to check is that we are using the 64-bit v1 ABI, ie. function descriptors. So also add a #define for that, which simplifies several checks. Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* ftrace: Match dot symbols when searching functions on ppc64Thiago Jung Bauermann2016-04-271-0/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In the ppc64 big endian ABI, function symbols point to function descriptors. The symbols which point to the function entry points have a dot in front of the function name. Consequently, when the ftrace filter mechanism searches for the symbol corresponding to an entry point address, it gets the dot symbol. As a result, ftrace filter users have to be aware of this ABI detail on ppc64 and prepend a dot to the function name when setting the filter. The perf probe command insulates the user from this by ignoring the dot in front of the symbol name when matching function names to symbols, but the sysfs interface does not. This patch makes the ftrace filter mechanism do the same when searching symbols. Fixes the following failure in ftracetest's kprobe_ftrace.tc: .../kprobe_ftrace.tc: line 9: echo: write error: Invalid argument That failure is on this line of kprobe_ftrace.tc: echo _do_fork > set_ftrace_filter This is because there's no _do_fork entry in the functions list: # cat available_filter_functions | grep _do_fork ._do_fork This change introduces no regressions on the perf and ftracetest testsuite results. Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: linuxppc-dev@lists.ozlabs.org Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* powerpc/ftrace: Add support for -mprofile-kernel ftrace ABITorsten Duwe2016-03-071-16/+87
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The gcc switch -mprofile-kernel defines a new ABI for calling _mcount() very early in the function with minimal overhead. Although mprofile-kernel has been available since GCC 3.4, there were bugs which were only fixed recently. Currently it is known to work in GCC 4.9, 5 and 6. Additionally there are two possible code sequences generated by the flag, the first uses mflr/std/bl and the second is optimised to omit the std. Currently only gcc 6 has the optimised sequence. This patch supports both sequences. Initial work started by Vojtech Pavlik, used with permission. Key changes: - rework _mcount() to work for both the old and new ABIs. - implement new versions of ftrace_caller() and ftrace_graph_caller() which deal with the new ABI. - updates to __ftrace_make_nop() to recognise the new mcount calling sequence. - updates to __ftrace_make_call() to recognise the nop'ed sequence. - implement ftrace_modify_call(). - updates to the module loader to surpress the toc save in the module stub when calling mcount with the new ABI. Reviewed-by: Balbir Singh <bsingharora@gmail.com> Signed-off-by: Torsten Duwe <duwe@suse.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* powerpc/ftrace: Use generic ftrace_modify_all_code()Torsten Duwe2016-03-071-12/+5
| | | | | | | | | | | | | | Convert powerpc's arch_ftrace_update_code() from its own version to use the generic default functionality (without stop_machine -- our instructions are properly aligned and the replacements atomic). With this we gain error checking and the much-needed function_trace_op handling. Reviewed-by: Balbir Singh <bsingharora@gmail.com> Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> Signed-off-by: Torsten Duwe <duwe@suse.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* powerpc/module: Mark module stubs with a magic valueMichael Ellerman2016-03-071-10/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When a module is loaded, calls out to the kernel go via a stub which is generated at runtime. One of these stubs is used to call _mcount(), which is the default target of tracing calls generated by the compiler with -pg. If dynamic ftrace is enabled (which it typically is), another stub is used to call ftrace_caller(), which is the target of tracing calls when ftrace is actually active. ftrace then wants to disable the calls to _mcount() at module startup, and enable/disable the calls to ftrace_caller() when enabling/disabling tracing - all of these it does by patching the code. As part of that code patching, the ftrace code wants to confirm that the branch it is about to modify, is in fact a call to a module stub which calls _mcount() or ftrace_caller(). Currently it does that by inspecting the instructions and confirming they are what it expects. Although that works, the code to do it is pretty intricate because it requires lots of knowledge about the exact format of the stub. We can make that process easier by marking the generated stubs with a magic value, and then looking for that magic value. Altough this is not as rigorous as the current method, I believe it is sufficient in practice. Reviewed-by: Balbir Singh <bsingharora@gmail.com> Reviewed-by: Torsten Duwe <duwe@suse.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* Merge tag 'powerpc-3.19-1' of ↵Linus Torvalds2014-12-111-58/+15
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux Pull powerpc updates from Michael Ellerman: "Some nice cleanups like removing bootmem, and removal of __get_cpu_var(). There is one patch to mm/gup.c. This is the generic GUP implementation, but is only used by us and arm(64). We have an ack from Steve Capper, and although we didn't get an ack from Andrew he told us to take the patch through the powerpc tree. There's one cxl patch. This is in drivers/misc, but Greg said he was happy for us to manage fixes for it. There is an infrastructure patch to support an IPMI driver for OPAL. There is also an RTC driver for OPAL. We weren't able to get any response from the RTC maintainer, Alessandro Zummo, so in the end we just merged the driver. The usual batch of Freescale updates from Scott" * tag 'powerpc-3.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux: (101 commits) powerpc/powernv: Return to cpu offline loop when finished in KVM guest powerpc/book3s: Fix partial invalidation of TLBs in MCE code. powerpc/mm: don't do tlbie for updatepp request with NO HPTE fault powerpc/xmon: Cleanup the breakpoint flags powerpc/xmon: Enable HW instruction breakpoint on POWER8 powerpc/mm/thp: Use tlbiel if possible powerpc/mm/thp: Remove code duplication powerpc/mm/hugetlb: Sanity check gigantic hugepage count powerpc/oprofile: Disable pagefaults during user stack read powerpc/mm: Check for matching hpte without taking hpte lock powerpc: Drop useless warning in eeh_init() powerpc/powernv: Cleanup unused MCE definitions/declarations. powerpc/eeh: Dump PHB diag-data early powerpc/eeh: Recover EEH error on ownership change for BCM5719 powerpc/eeh: Set EEH_PE_RESET on PE reset powerpc/eeh: Refactor eeh_reset_pe() powerpc: Remove more traces of bootmem powerpc/pseries: Initialise nvram_pstore_info's buf_lock cxl: Name interrupts in /proc/interrupt cxl: Return error to PSL if IRQ demultiplexing fails & print clearer warning ...
| * powerpc/ftrace: simplify prepare_ftrace_returnAnton Blanchard2014-11-101-46/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of passing in the stack address of the link register to be modified, just pass in the old value and return the new value and rely on ftrace_graph_caller to do the modification. This removes the exception handling around the stack update - it isn't needed and we weren't consistent about it. Later on we would do an unprotected modification: if (!ftrace_graph_entry(&trace)) { *parent = old; Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| * powerpc/ftrace: Remove mod_return_to_handlerAnton Blanchard2014-11-101-12/+2
| | | | | | | | | | | | | | | | | | mod_return_to_handler is the same as return_to_handler, except it handles the change of the TOC (r2). Add this into return_to_handler and remove mod_return_to_handler. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* | ftrace: Add more information to ftrace_bug() outputSteven Rostedt (Red Hat)2014-11-111-1/+1
|/ | | | | | | | | | | | | | | | | | With the introduction of the dynamic trampolines, it is useful that if things go wrong that ftrace_bug() produces more information about what the current state is. This can help debug issues that may arise. Ftrace has lots of checks to make sure that the state of the system it touchs is exactly what it expects it to be. When it detects an abnormality it calls ftrace_bug() and disables itself to prevent any further damage. It is crucial that ftrace_bug() produces sufficient information that can be used to debug the situation. Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Borislav Petkov <bp@suse.de> Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Tested-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* powerpc/ftrace: Add call to ftrace_graph_is_dead() in function graph codeSteven Rostedt (Red Hat)2014-07-181-0/+3
| | | | | | | | | | | | | | | | ftrace_stop() is going away as it disables parts of function tracing that affects users that should not be affected. But ftrace_graph_stop() is built on ftrace_stop(). Here's another example of killing all of function tracing because something went wrong with function graph tracing. Instead of disabling all users of function tracing on function graph error, disable only function graph tracing. To do this, the arch code must call ftrace_graph_is_dead() before it implements function graph. Cc: Anton Blanchard <anton@samba.org> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* powerpc/ftrace: Use pr_fmt() to namespace error messagesMichael Ellerman2014-06-241-23/+20
| | | | | | | | | | | | | | The printks() in our ftrace code have no prefix, so they appear on the console with very little context, eg: Branch out of range Use pr_fmt() & pr_err() to add a prefix. While we're at it, collapse a few split lines that don't need to be, and add a missing newline to one message. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc/ftrace: Fix nop of modules on 64bit LE (ABIv2)Michael Ellerman2014-06-241-3/+4
| | | | | | | | | | | | | | | | | There is a bug in the handling of the function entry when we are nopping out a branch from a module in ftrace. We compare the result of module_trampoline_target() with the value of ppc_function_entry(), and expect them to be true. But they never will be. module_trampoline_target() will always return the global entry point of the function, whereas ppc_function_entry() will always return the local. Fix it by using the newly added ppc_global_function_entry(). Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc/ftrace: Fix inverted check of create_branch()Michael Ellerman2014-06-241-1/+1
| | | | | | | | | | | | | | | | | | | In commit 24a1bdc35, "Fix ABIv2 issues with __ftrace_make_call", Anton changed the logic that creates and patches the branch, and added a thinko in the check of create_branch(). create_branch() returns the instruction that was generated, so if we get zero then it succeeded. The result is we can't ftrace modules: Branch out of range WARNING: at ../kernel/trace/ftrace.c:1638 ftrace failed to modify [<d000000004ba001c>] fuse_req_init_context+0x1c/0x90 [fuse] We should probably fix patch_instruction() to do that check and make the API saner, but that's a separate patch. For now just invert the test. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc/ftrace: Fix typo in mask of opcodeMichael Ellerman2014-06-241-1/+1
| | | | | | | | | | | | | | | | | | | In commit 24a1bdc35, "Fix ABIv2 issues with __ftrace_make_call", Anton changed the logic that checks for the expected code sequence when patching a module. We missed the typo in the mask, 0xffff00000 should be 0xffff0000, which has the effect of making the test always true. That makes it impossible to ftrace against modules, eg: Unexpected call sequence: 48000008 e8410018 WARNING: at ../kernel/trace/ftrace.c:1638 ftrace failed to modify [<d000000007cf001c>] rng_dev_open+0x1c/0x70 [rng_core] Reported-by: David Binderman <dcb314@hotmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc/ftrace: Fix ABIv2 issues with __ftrace_make_callAnton Blanchard2014-04-231-21/+19
| | | | | | | | | | | __ftrace_make_call assumed ABIv1 TOC stack offsets, so it broke on ABIv2. While we are here, we can simplify the instruction modification code. Since we always update one instruction there is no need to probe_kernel_write and flush_icache_range, just use patch_branch. Signed-off-by: Anton Blanchard <anton@samba.org>
* powerpc/ftrace: Use module loader helpers to parse trampolinesAnton Blanchard2014-04-231-77/+20
| | | | | | | | Now we have is_module_trampoline() and module_trampoline_target() we can remove a bunch of intimate kernel module trampoline knowledge from ftrace. Signed-off-by: Anton Blanchard <anton@samba.org>
* Merge tag 'trace-3.15' of ↵Linus Torvalds2014-04-031-6/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing updates from Steven Rostedt: "Most of the changes were largely clean ups, and some documentation. But there were a few features that were added: Uprobes now work with event triggers and multi buffers and have support under ftrace and perf. The big feature is that the function tracer can now be used within the multi buffer instances. That is, you can now trace some functions in one buffer, others in another buffer, all functions in a third buffer and so on. They are basically agnostic from each other. This only works for the function tracer and not for the function graph trace, although you can have the function graph tracer running in the top level buffer (or any tracer for that matter) and have different function tracing going on in the sub buffers" * tag 'trace-3.15' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (45 commits) tracing: Add BUG_ON when stack end location is over written tracepoint: Remove unused API functions Revert "tracing: Move event storage for array from macro to standalone function" ftrace: Constify ftrace_text_reserved tracepoints: API doc update to tracepoint_probe_register() return value tracepoints: API doc update to data argument ftrace: Fix compilation warning about control_ops_free ftrace/x86: BUG when ftrace recovery fails ftrace: Warn on error when modifying ftrace function ftrace: Remove freelist from struct dyn_ftrace ftrace: Do not pass data to ftrace_dyn_arch_init ftrace: Pass retval through return in ftrace_dyn_arch_init() ftrace: Inline the code from ftrace_dyn_table_alloc() ftrace: Cleanup of global variables ftrace_new_pgs and ftrace_update_cnt tracing: Evaluate len expression only once in __dynamic_array macro tracing: Correctly expand len expressions from __dynamic_array macro tracing/module: Replace include of tracepoint.h with jump_label.h in module.h tracing: Fix event header migrate.h to include tracepoint.h tracing: Fix event header writeback.h to include tracepoint.h tracing: Warn if a tracepoint is not set via debugfs ...
| * ftrace: Do not pass data to ftrace_dyn_arch_initJiri Slaby2014-03-071-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As the data parameter is not really used by any ftrace_dyn_arch_init, remove that from ftrace_dyn_arch_init. This also removes the addr local variable from ftrace_init which is now unused. Note the documentation was imprecise as it did not suggest to set (*data) to 0. Link: http://lkml.kernel.org/r/1393268401-24379-4-git-send-email-jslaby@suse.cz Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: linux-arch@vger.kernel.org Signed-off-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * ftrace: Pass retval through return in ftrace_dyn_arch_init()Jiri Slaby2014-03-071-5/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | No architecture uses the "data" parameter in ftrace_dyn_arch_init() in any way, it just sets the value to 0. And this is used as a return value in the caller -- ftrace_init, which just checks the retval against zero. Note there is also "return 0" in every ftrace_dyn_arch_init. So it is enough to check the retval and remove all the indirect sets of data on all archs. Link: http://lkml.kernel.org/r/1393268401-24379-3-git-send-email-jslaby@suse.cz Cc: linux-arch@vger.kernel.org Signed-off-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | powerpc/ftrace: bugfix for test_24bit_addrLiu Ping Fan2014-02-281-0/+1
|/ | | | | | | | The branch target should be the func addr, not the addr of func_descr_t. So using ppc_function_entry() to generate the right target addr. Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc: Make ftrace endian-safe.Eugene Surovegin2013-10-111-0/+4
| | | | | Signed-off-by: Eugene Surovegin <surovegin@google.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc/ftrace: Trace function graph entry before updating indexSteven Rostedt2012-07-271-6/+5
| | | | | | | | | | | | | | | | | | As Colin Cross ported my x86 change to ARM, he also pointed out that powerpc is also behind in this fix. The commit 722b3c746953 "ftrace/graph: Trace function entry before updating index" fixes an issue with function graph tracing for x86, where if the called entry function decides not to trace interrupts, it can fail the check if an interrupt comes in just after the curr_ret_stack is updated. The solution is to call the entry function first, then update the curr_ret_stack if the entry function wants to be traced. Cc: Colin Cross <ccross@android.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc/ftrace: Fix assembly trampoline register usageroger blofeld2012-07-111-6/+6
| | | | | | | | | Just like the module loader, ftrace needs to be updated to use r12 instead of r11 with newer gcc's. Signed-off-by: Roger Blofeld <blofeldus@yahoo.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> CC: stable@vger.kernel.org
* powerpc/ftrace: Use patch_instruction instead of probe_kernel_write()Steven Rostedt2012-07-031-13/+4
| | | | | | | | | The patch_instruction() interface is made to modify kernel text. It is safer to use that then the probe_kernel_write() when modifying kernel code. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc/ftrace: Have PPC skip updating with stop_machine()Steven Rostedt2012-07-031-0/+52
| | | | | | | | | | | | PowerPC does not have the synchronization issues that x86 has with modifying code on one CPU while another CPU is executing it. The other CPU will either see the old or new code without any issues, unlike x86 which may issue a GPF. Instead of calling the heavy stop_machine, just update the code. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc/ftrace: Implement raw syscall tracepoints on PowerPCIan Munsie2011-05-261-0/+8
| | | | | | | | | | | | | | | | | | | | This patch implements the raw syscall tracepoints on PowerPC and exports them for ftrace syscalls to use. To minimise reworking existing code, I slightly re-ordered the thread info flags such that the new TIF_SYSCALL_TRACEPOINT bit would still fit within the 16 bits of the andi. instruction's UI field. The instructions in question are in /arch/powerpc/kernel/entry_{32,64}.S to and the _TIF_SYSCALL_T_OR_A with the thread flags to see if system call tracing is enabled. In the case of 64bit PowerPC, arch_syscall_addr and arch_syscall_match_sym_name are overridden to allow ftrace syscalls to work given the unusual system call table structure and symbol names that start with a period. Signed-off-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* Merge branch 'tracing-fixes-for-linus' of ↵Linus Torvalds2009-06-201-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (24 commits) tracing/urgent: warn in case of ftrace_start_up inbalance tracing/urgent: fix unbalanced ftrace_start_up function-graph: add stack frame test function-graph: disable when both x86_32 and optimize for size are configured ring-buffer: have benchmark test print to trace buffer ring-buffer: do not grab locks in nmi ring-buffer: add locks around rb_per_cpu_empty ring-buffer: check for less than two in size allocation ring-buffer: remove useless compile check for buffer_page size ring-buffer: remove useless warn on check ring-buffer: use BUF_PAGE_HDR_SIZE in calculating index tracing: update sample event documentation tracing/filters: fix race between filter setting and module unload tracing/filters: free filter_string in destroy_preds() ring-buffer: use commit counters for commit pointer accounting ring-buffer: remove unused variable ring-buffer: have benchmark test handle discarded events ring-buffer: prevent adding write in discarded area tracing/filters: strloc should be unsigned short tracing/filters: operand can be negative ... Fix up kmemcheck-induced conflict in kernel/trace/ring_buffer.c manually
| * function-graph: add stack frame testSteven Rostedt2009-06-181-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In case gcc does something funny with the stack frames, or the return from function code, we would like to detect that. An arch may implement passing of a variable that is unique to the function and can be saved on entering a function and can be tested when exiting the function. Usually the frame pointer can be used for this purpose. This patch also implements this for x86. Where it passes in the stack frame of the parent function, and will test that frame on exit. There was a case in x86_32 with optimize for size (-Os) where, for a few functions, gcc would align the stack frame and place a copy of the return address into it. The function graph tracer modified the copy and not the actual return address. On return from the funtion, it did not go to the tracer hook, but returned to the parent. This broke the function graph tracer, because the return of the parent (where gcc did not do this funky manipulation) returned to the location that the child function was suppose to. This caused strange kernel crashes. This test detected the problem and pointed out where the issue was. This modifies the parameters of one of the functions that the arch specific code calls, so it includes changes to arch code to accommodate the new prototype. Note, I notice that the parsic arch implements its own push_return_trace. This is now a generic function and the ftrace_push_return_trace should be used instead. This patch does not touch that code. Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Helge Deller <deller@gmx.de> Cc: Kyle McMartin <kyle@mcmartin.ca> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | powerpc/ftrace: Use PPC_INST_NOP directlyMichael Ellerman2009-06-021-7/+2
| | | | | | | | | | | | | | There's no need to wrap PPC_INST_NOP in a static inline. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* | powerpc/ftrace: Remove unused macrosMichael Ellerman2009-06-021-8/+0
| | | | | | | | | | | | | | | | | | These macros were used in the original port, but since commit e4486fe316 (ftrace, use probe_kernel API to modify code) they are unused. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* | powerpc/ftrace: Use ppc_function_entry() instead of GET_ADDRMichael Ellerman2009-06-021-9/+3
|/ | | | | | | Use ppc_function_entry() from code-patching.h. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc/ftrace: Fix constraint to be early clobberSteven Rostedt2009-05-181-1/+1
| | | | | | | | | | | | | | | After upgrading my distcc boxes from gcc 4.2.2 to 4.4.0, the function graph tracer broke. This was discovered on my x86 boxes. The issue is that gcc used the same register for an output as it did for an input in an asm statement. I first thought this was a bug in gcc and reported it. I was notified that gcc was correct and that the output had to be flagged as an "early clobber". I noticed that powerpc had the same issue and this patch fixes it. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc/ftrace: Use pr_devel() in ftrace.cMichael Ellerman2009-05-181-10/+10
| | | | | | | | | | | | | | | | | | | | pr_debug() can now result in code being generated even when #DEBUG is not defined. That's not really desirable in the ftrace code which we want to be snappy. With CONFIG_DYNAMIC_DEBUG=y: size before: text data bss dec hex filename 3334 672 4 4010 faa arch/powerpc/kernel/ftrace.o size after: text data bss dec hex filename 2616 360 4 2980 ba4 arch/powerpc/kernel/ftrace.o Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc/ftrace: Fix printf format warningMichael Ellerman2009-04-071-1/+1
| | | | | | | | | | | 'tramp' is an unsigned long, so print it with %lx. Fixes the following build warning: arch/powerpc/kernel/ftrace.c:291: error: format ‘%x’ expects type ‘unsigned int’, but argument 2 has type ‘long unsigned int’ Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
* powerpc/ftrace: Fix #if that should be #ifdefMichael Ellerman2009-04-071-1/+1
| | | | | | | | | | | | | Commit bb7253403f7a4670a128e4c080fd8ea1bd4d5029 ("powerpc64, ftrace: save toc only on modules for function graph"), added an #if CONFIG_PPC64. This changes it to #ifdef. Fixes the following warning on 32-bit builds: arch/powerpc/kernel/ftrace.c:562:5: error: "CONFIG_PPC64" is not defined Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
* tracing, powerpc: fix powerpc tree and tracing tree interactionStephen Rothwell2009-04-021-5/+1
| | | | | | | | | | | | | | | | | | | | | | | Today's linux-next build (powerpc allyesconfig) failed like this: arch/powerpc/kernel/ftrace.c: In function 'prepare_ftrace_return': arch/powerpc/kernel/ftrace.c:612: warning: passing argument 3 of 'ftrace_push_return_trace' makes pointer from integer without a cast arch/powerpc/kernel/ftrace.c:612: error: too many arguments to function 'ftrace_push_return_trace' Caused by commit 5d1a03dc541dc6672e60e57249ed22f40654ca47 ("function-graph: moved the timestamp from arch to generic code") from the tracing tree which (removed an argument from ftrace_push_return_trace()) interacting with commit 6794c78243bfda020ab184d6d578944f8e90d26c ("powerpc64: port of the function graph tracer") from the powerpc tree. Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Steven Rostedt <srostedt@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: <linuxppc-dev@ozlabs.org> LKML-Reference: <20090327230834.93d0221d.sfr@canb.auug.org.au> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* powerpc: Unify opcode definitions and supportKumar Gala2009-02-231-4/+4
| | | | | | | | | | | | | | | | | Create a new header that becomes a single location for defining PowerPC opcodes used by code that is either generationg instructions at runtime (fixups, debug, etc.), emulating instructions, or just compiling instructions old assemblers don't know about. We currently don't handle the floating point emulation or alignment decode as both are better handled by the specific decode support they already have. Added support for the new dcbzl, dcbal, msgsnd, tlbilx, & wait instructions since older assemblers don't know about them. Signed-off-by: Kumar Gala <galak@kernel.crashing.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc, ftrace: use create_branch lib functionSteven Rostedt2009-02-231-13/+1
| | | | | | | | | | | | | | | | | | | | | Impact: clean up, remove duplicate code When ftrace was first ported to PowerPC, there existed a create_function_call that would create the instruction to make a call to a given address. Unfortunately, this call expected to write to the address it was given, and since it used the address to calculate the offset, it could not be faked. ftrace needed a way to create the instruction without actually writing that instruction to the text section. So ftrace had to implement its own code. Now we have create_branch in the code patching library, which does exactly what ftrace needs. This patch replaces ftrace's implementation with the library function. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc, ftrace: use unsigned int for instruction manipulationSteven Rostedt2009-02-231-27/+18
| | | | | | | | | | | | | | | | | | The original port of ftrace to PowerPC kept a lot of the code used by x86. Some of this code was to handle x86's 5 byte instruction. This was handled by using character arrays to manipulate the code. PowerPC has a consistent 4 byte instruction. Using unsigned ints makes the code more efficient as well as more readable. By converting to use unsigned ints to represent instructions, I was able to remove the side effects that were needed for manipulating character strings. i.e. memcpy and memcmp Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc32, ftrace: port function graph tracer to ppc32, static onlySteven Rostedt2009-02-231-1/+1
| | | | | | | | | This patch ports the function graph tracer for PowerPC, but only for static function tracing. Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc64, ftrace: save toc only on modules for function graphSteven Rostedt2009-02-231-2/+11
| | | | | | | | | | | | | | | | | | | | | | | | The TOCS used by modules are different than the one used by the core kernel code. The function graph tracer must save and restore the TOC whenever it traces a module call. But this is an added overhead to burden the majority of core kernel code being traced. Benjamin Herrenschmidt suggested in testing the entry of the call to tell if it is a core kernel function or a module. He recommended using the REGION_ID() macro to perform this test. This patch implements Benjamin's idea, and uses a different return_to_handler routine dependent on if the entry is a core kernel function or not. The module version saves the TOC, where as the core kernel version does not. Geoff Lavand tested on PS3. Tested-by: Geoff Levand <geoffrey.levand@am.sony.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc64, tracing: add function graph tracer with dynamic tracingSteven Rostedt2009-02-231-6/+41
| | | | | | | | | | | | This is the port of the function graph tracer to PowerPC with dynamic tracing. Geoff Lavand tested on PS3. Tested-by: Geoff Levand <geoffrey.levand@am.sony.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc64: port of the function graph tracerSteven Rostedt2009-02-231-2/+77
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is a port of the function graph tracer that was written by Frederic Weisbecker for the x86. This only works for PPC64 at the moment and only for static tracing. PPC32 and dynamic function graph tracing support will come later. The trace produces a visual calling of functions: # tracer: function_graph # # CPU DURATION FUNCTION CALLS # | | | | | | | 0) 2.224 us | } 0) ! 271.024 us | } 0) ! 320.080 us | } 0) ! 324.656 us | } 0) ! 329.136 us | } 0) | .put_prev_task_fair() { 0) | .update_curr() { 0) 2.240 us | .update_min_vruntime(); 0) 6.512 us | } 0) 2.528 us | .__enqueue_entity(); 0) + 15.536 us | } 0) | .pick_next_task_fair() { 0) 2.032 us | .__pick_next_entity(); 0) 2.064 us | .__clear_buddies(); 0) | .set_next_entity() { 0) 2.672 us | .__dequeue_entity(); 0) 6.864 us | } Geoff Lavand tested on PS3. Tested-by: Geoff Levand <geoffrey.levand@am.sony.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc, ftrace: fix compile error when modules not configuredSteven Rostedt2009-02-231-1/+15
| | | | | | | | | | Michael Neuling reported a compile bug when dynamic ftrace was configured in and modules were not. This was due to the ftrace code referencing module specific structures. Reported-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* ftrace, powerpc: replace debug macro with proper pr_deugSteven Rostedt2009-02-231-16/+10
| | | | | | | | | | Impact: cleanup The PowerPC ftrace code uses a hacked up DEBUGP macro for prints. This patch converts it to the standard pr_debug. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc/ftrace: Fix math to calculate offset in TOCSteven Rostedt2009-02-101-2/+3
| | | | | | | | | | | | | Impact: fix dynamic ftrace with large modules in PPC64 The math to calculate the offset into the TOC that is taken from reading the trampoline is incorrect. The bottom half of the offset is a signed extended short. The current code was using an OR to create the offset when it should have been using an addition. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Acked-by: Geoff Levand <geoffrey.levand@am.sony.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc: ftrace, use create_branchSteven Rostedt2008-11-281-42/+12
| | | | | | | | | | | | | | | Impact: clean up Paul Mackerras pointed out that the code to determine if the branch can reach the destination is incorrect. Michael Ellerman suggested to pull out the code from create_branch and use that. Simply using create_branch is probably the best. Reported-by: Michael Ellerman <michael@ellerman.id.au> Reported-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* powerpc: ftrace, added missing icache flushSteven Rostedt2008-11-281-0/+9
| | | | | | | | | | | Impact: fix to PowerPC code modification After modifying code it is essential to flush the icache. This patch adds the missing flush. Reported-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* powerpc: ftrace, fix cast aliasing and add code verificationSteven Rostedt2008-11-281-56/+65
| | | | | | | | | | | | | | Impact: clean up and robustness addition This patch addresses the comments made by Paul Mackerras. It removes the type casting between unsigned int and unsigned char pointers, and replaces them with a use of all unsigned int. Verification that the jump is indeed made to a trampoline has also been added. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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