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* MIPS: Ftrace: Fix the CONFIG_DYNAMIC_FTRACE=n compileThomas Gleixner2011-09-211-19/+20
| | | | | | | | | | | | | | arch/mips/kernel/ftrace.c: In function ‘ftrace_get_parent_ra_addr’: arch/mips/kernel/ftrace.c:212: error: implicit declaration of function ‘in_kernel_space’ arch/mips/kernel/ftrace.c: In function ‘prepare_ftrace_return’: arch/mips/kernel/ftrace.c:314: error: ‘MCOUNT_OFFSET_INSNS’ undeclared (first use in this function) arch/mips/kernel/ftrace.c:314: error: (Each undeclared identifier is reported only once arch/mips/kernel/ftrace.c:314: error: for each function it appears in.) Signed-off-by: Thomas Gleixner <tglx@linutronix.de> To: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/2634/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* MIPS: Mask jump target in ftrace_dyn_arch_init_insns().David Daney2011-05-101-2/+3
| | | | | | | | | | | | The current code is abusing the uasm interface by passing jump target addresses with high bits set. Mask the addresses to avoid annoying messages at boot time. Signed-off-by: David Daney <ddaney@caviumnetworks.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Wu Zhangjin <wuzhangjin@gmail.com> Patchwork: https://patchwork.linux-mips.org/patch/1922/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* MIPS, Tracing: Fix set_graph_function of function graph tracerWu Zhangjin2011-03-141-2/+9
| | | | | | | | | | | | | | | | | | | trace.func should be set to the recorded ip of the mcount calling site in the __mcount_loc section to filter the function entries configured through the tracing/set_graph_function interface, but before, this is set to the self_ra(the return address of mcount), which has made set_graph_function not work as expected. This fixes it via calculating the right recorded ip in the __mcount_loc section and assign it to trace.func. Reported-by: Zhiping Zhong <xzhong86@163.com> Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com> Cc: Steven Rostedt <srostedt@redhat.com> Cc: Sergei Shtylyov <sshtylyov@mvista.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/2017/ Signed-off-by: Ralf Baechle <ralf@duck.linux-mips.net>
* MIPS, Tracing: Clean up ftrace_make_nop()Wu Zhangjin2011-03-141-32/+38
| | | | | | | | | | | | This moves the comments out of ftrace_make_nop() and cleans it. At the same time, a macro MCOUNT_OFFSET_INSNS is defined for sharing with the next patch. Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com> Cc: Steven Rostedt <srostedt@redhat.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/2008/ Signed-off-by: Ralf Baechle <ralf@duck.linux-mips.net>
* MIPS, Tracing: Clean up prepare_ftrace_return()Wu Zhangjin2011-03-141-27/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The old prepare_ftrace_return() for MIPS is confused and have introduced some problem. This patch cleans up the names of the arguments, variables and related functions. For MIPS, the 2nd argument of prepare_ftrace_return() is not really the 'selfpc' described in ftrace-design.txt but instead it is the self return address. This did break the compatibility of the generic interface but really reduced one unneeded calculation for to get the current function name, the parent return address and the self return address are enough, no need to tranform the self return address to the self address. But set_graph_function of function graph tracer is an exception, it does need the 2nd argument of prepare_ftrace_return() as 'selfpc', for it will use 'selfpc' to match user's configuration of function graph entries, but in reality, it doesn't need the 'selfpc' but the recorded ip address of the mcount calling site in the __mcount_loc section. So, the 2nd argument of prepare_ftrace_return() is not important, the real requirement is the right recorded ip address should be calculated and assign to trace.func, this will be fixed in the next patches. Reported-by: Zhiping Zhong <xzhong86@163.com> Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com> Cc: Steven Rostedt <srostedt@redhat.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/2007/ Signed-off-by: Ralf Baechle <ralf@duck.linux-mips.net>
* MIPS, Tracing: Substitute in_kernel_space() for in_module()Wu Zhangjin2011-03-141-27/+27
| | | | | | | | | | | | | | The old in_module() may not work in some situations(e.g. when module & kernel are in the same address space when CONFIG_MAPPED_KERNEL=y), The in_kernel_space() is more generic and it is also easy to be implemented via cloning the existing core_kernel_text(), so, replace the in_module() with in_kernel_space(). Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com> Cc: Steven Rostedt <srostedt@redhat.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/2005/ Signed-off-by: Ralf Baechle <ralf@duck.linux-mips.net>
* MIPS, Tracing: Speed up function graph tracerWu Zhangjin2011-03-141-7/+7
| | | | | | | | | | | | This simply moves the "ip-=4" statement down to the end of the do { ... } while (...); loop, which reduces one unneeded subtration and the subsequent memory loading and comparison. Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com> Cc: Steven Rostedt <srostedt@redhat.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/2006/ Signed-off-by: Ralf Baechle <ralf@duck.linux-mips.net>
* MIPS: Tracing: Cleanup of address space checkingWu Zhangjin2010-07-051-3/+19
| | | | | | | | | | | | | | | | | | | This patch adds an inline function in_module() to check which space the instruction pointer in, kernel space or module space. Note: This will not work when the kernel space and module space are the same. If they are the same, we need to modify scripts/recordmcount.pl, ftrace_make_nop/call() and the other related parts to ensure the enabling/disabling of the calling site to _mcount is right for both kernel and module. [Ralf: It also is still incorrect for some 64-bit kernels.] Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com> Cc: linux-mips <linux-mips@linux-mips.org> Cc: David Daney <david.s.daney@gmail.com> Patchwork: http://patchwork.linux-mips.org/patch/1232/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* MIPS: Tracing: Cleanup of function graph tracerWu Zhangjin2010-07-051-22/+26
| | | | | | | | | | Cleans up comments and ftrace_get_parent_addr() of function graph tracer. Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com> Cc: linux-mips <linux-mips@linux-mips.org> Cc: David Daney <david.s.daney@gmail.com> Patchwork: http://patchwork.linux-mips.org/patch/1231/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* MIPS: Tracing: Reduce the overhead of dynamic Function TracerWu Zhangjin2010-07-051-44/+49
| | | | | | | | | | | | | | | | With the help of uasm this patch encodes the instructions of the dynamic function tracer in ftrace_dyn_arch_init() when initializing it. As a result we can remove the dynamic encoding of instructions in ftrace_make_nop()/call(), ftrace_enable_ftrace_graph_caller() and remove the macro jump_insn_encode() and at last this reduce the overhead of dynamic Function Tracer. This also is cleaner. Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com> Cc: linux-mips <linux-mips@linux-mips.org> Cc: David Daney <david.s.daney@gmail.com> Patchwork: http://patchwork.linux-mips.org/patch/1230/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* MIPS: Tracing: Cleanup of instructions usedWu Zhangjin2010-07-051-8/+11
| | | | | | | | | | | | | This patch adds some cleanups of the instructions: o use macros instead of magic numbers o use macros instead of variables to reduce some overhead o add new macro for the jal instruction Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com> Cc: linux-mips <linux-mips@linux-mips.org> Cc: David Daney <david.s.daney@gmail.com> Patchwork: http://patchwork.linux-mips.org/patch/1229/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* MIPS: Tracing: Fix 32-bit support with -mmcount-ra-addressWu Zhangjin2010-07-051-2/+14
| | | | | | | | | | | | For 32-bit kernel the -mmcount-ra-address option of gcc 4.5 emits one extra instruction before calling to _mcount so we need to use a different "b 1f" for it. Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com> Cc: linux-mips <linux-mips@linux-mips.org> Cc: David Daney <david.s.daney@gmail.com> Patchwork: http://patchwork.linux-mips.org/patch/1228/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* MIPS: Loongson: Change the Email address of Wu ZhangjinWu Zhangjin2010-02-271-1/+1
| | | | | | | | | | | | Currently wuzj@lemote.com is not usable; change it to wuzhangjin@gmail.com. Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com> Cc: linux-mips@linux-mips.org Cc: yanh@lemote.com Cc: huhb@lemote.com Cc: zhangfx@lemote.com Patchwork: http://patchwork.linux-mips.org/patch/829/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* MIPS: Tracing: Make function graph tracer work with -mmcount-ra-addressWu Zhangjin2009-12-171-7/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | That thread "MIPS: Add option to pass return address location to _mcount" from "David Daney <ddaney@caviumnetworks.com>" have added a new option -mmcount-ra-address to gcc(4.5) for MIPS to transfer the location of the return address to _mcount. Benefit from this new feature, function graph tracer on MIPS will be easier and safer to hijack the return address of the kernel function, which will save some overhead and make the whole thing more reliable. In this patch, at first, try to enable the option -mmcount-ra-address in arch/mips/Makefile with cc-option, if gcc support it, it will be enabled, otherwise, no side effect. and then, we need to support this new option of gcc 4.5 and also support the old gcc versions. with _mcount in the old gcc versions, it's not easy to get the location of return address(tracing: add function graph tracer support for MIPS), so, we do it in a C function: ftrace_get_parent_addr(ftrace.c), but with -mmcount-ra-address, only several instructions need to get what we want, so, I put into asm(mcount.S). and also, as the $12(t0) is used by -mmcount-ra-address for transferring the localtion of return address to _mcount, we need to save it into the stack and restore it when enabled dynamic function tracer, 'Cause we have called "ftrace_call" before "ftrace_graph_caller", which may destroy $12(t0). (Thanks to David for providing that -mcount-ra-address and giving the idea of KBUILD_MCOUNT_RA_ADDRESS, both of them have made the whole thing more beautiful!) Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Nicholas Mc Guire <der.herr@hofr.at> Cc: zhangfx@lemote.com Cc: Wu Zhangjin <wuzhangjin@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Patchwork: http://patchwork.linux-mips.org/patch/681/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* MIPS: Tracing: Make ftrace for MIPS work without -fno-omit-frame-pointerWu Zhangjin2009-12-171-15/+41
| | | | | | | | | | | | | | | | | | When remove the -fno-omit-frame-pointer, gcc will not save the frame pointer for us, we need to save one ourselves. Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Nicholas Mc Guire <der.herr@hofr.at> Cc: zhangfx@lemote.com Cc: Wu Zhangjin <wuzhangjin@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Patchwork: http://patchwork.linux-mips.org/patch/679/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* MIPS: Tracing: Add dynamic function graph tracer for MIPSWu Zhangjin2009-12-171-0/+21
| | | | | | | | | | | | | | | | | | | | | | | This patch make function graph tracer work with dynamic function tracer. To share the source code of dynamic function tracer(MCOUNT_SAVE_REGS), and avoid restoring the whole saved registers, we need to restore the ra register from the stack. (NOTE: This not work with 32bit! need to ensure why!) Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Nicholas Mc Guire <der.herr@hofr.at> Cc: zhangfx@lemote.com Cc: Wu Zhangjin <wuzhangjin@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Patchwork: http://patchwork.linux-mips.org/patch/678/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* MIPS: Tracing: Add function graph tracer support for MIPSWu Zhangjin2009-12-171-0/+106
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The implementation of function graph tracer for MIPS is a little different from X86. in MIPS, gcc(with -pg) only transfer the caller's return address(at) and the _mcount's return address(ra) to us. For the kernel part without -mlong-calls: move at, ra jal _mcount For the module part with -mlong-calls: lui v1, hi16bit_of_mcount addiu v1, v1, low16bit_of_mcount move at, ra jal _mcount Without -mlong-calls, if the function is a leaf, it will not save the return address(ra): ffffffff80101298 <au1k_wait>: ffffffff80101298: 67bdfff0 daddiu sp,sp,-16 ffffffff8010129c: ffbe0008 sd s8,8(sp) ffffffff801012a0: 03a0f02d move s8,sp ffffffff801012a4: 03e0082d move at,ra ffffffff801012a8: 0c042930 jal ffffffff8010a4c0 <_mcount> ffffffff801012ac: 00020021 nop so, we can hijack it directly in _mcount, but if the function is non-leaf, the return address is saved in the stack. ffffffff80133030 <copy_process>: ffffffff80133030: 67bdff50 daddiu sp,sp,-176 ffffffff80133034: ffbe00a0 sd s8,160(sp) ffffffff80133038: 03a0f02d move s8,sp ffffffff8013303c: ffbf00a8 sd ra,168(sp) ffffffff80133040: ffb70098 sd s7,152(sp) ffffffff80133044: ffb60090 sd s6,144(sp) ffffffff80133048: ffb50088 sd s5,136(sp) ffffffff8013304c: ffb40080 sd s4,128(sp) ffffffff80133050: ffb30078 sd s3,120(sp) ffffffff80133054: ffb20070 sd s2,112(sp) ffffffff80133058: ffb10068 sd s1,104(sp) ffffffff8013305c: ffb00060 sd s0,96(sp) ffffffff80133060: 03e0082d move at,ra ffffffff80133064: 0c042930 jal ffffffff8010a4c0 <_mcount> ffffffff80133068: 00020021 nop but we can not get the exact stack address(which saved ra) directly in _mcount, we need to search the content of at register in the stack space or search the "s{d,w} ra, offset(sp)" instruction in the text. 'Cause we can not prove there is only a match in the stack space, so, we search the text instead. as we can see, if the first instruction above "move at, ra" is not a store instruction, there should be a leaf function, so we hijack the at register directly via putting &return_to_handler into it, otherwise, we search the "s{d,w} ra, offset(sp)" instruction to get the stack offset, and then the stack address. we use the above copy_process() as an example, we at last find "ffbf00a8", 0xa8 is the stack offset, we plus it with s8(fp), that is the stack address, we hijack the content via writing the &return_to_handler in. If with -mlong-calls, since there are two more instructions above "move at, ra", so, we can move the pointer to the position above "lui v1, hi16bit_of_mcount". Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Nicholas Mc Guire <der.herr@hofr.at> Cc: zhangfx@lemote.com Cc: Wu Zhangjin <wuzhangjin@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Patchwork: http://patchwork.linux-mips.org/patch/677/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* MIPS: Tracing: Add dynamic function tracer supportWu Zhangjin2009-12-171-0/+112
With dynamic function tracer, by default, _mcount is defined as an "empty" function, it returns directly without any more action . When enabling it in user-space, it will jump to a real tracing function(ftrace_caller), and do the real job for us. Differ from the static function tracer, dynamic function tracer provides two functions ftrace_make_call()/ftrace_make_nop() to enable/disable the tracing of some indicated kernel functions(set_ftrace_filter). In the -v4 version, the implementation of this support is basically the same as X86 version does: _mcount is implemented as an empty function and ftrace_caller is implemented as a real tracing function respectively. But in this version, to support module tracing with the help of -mlong-calls in arch/mips/Makefile: MODFLAGS += -mlong-calls. The stuff becomes a little more complex. We need to cope with two different type of calling to _mcount. For the kernel part, the calling to _mcount(result of "objdump -hdr vmlinux"). is like this: 108: 03e0082d move at,ra 10c: 0c000000 jal 0 <fpcsr_pending> 10c: R_MIPS_26 _mcount 10c: R_MIPS_NONE *ABS* 10c: R_MIPS_NONE *ABS* 110: 00020021 nop For the module with -mlong-calls, it looks like this: c: 3c030000 lui v1,0x0 c: R_MIPS_HI16 _mcount c: R_MIPS_NONE *ABS* c: R_MIPS_NONE *ABS* 10: 64630000 daddiu v1,v1,0 10: R_MIPS_LO16 _mcount 10: R_MIPS_NONE *ABS* 10: R_MIPS_NONE *ABS* 14: 03e0082d move at,ra 18: 0060f809 jalr v1 In the kernel version, there is only one "_mcount" string for every kernel function, so, we just need to match this one in mcount_regex of scripts/recordmcount.pl, but in the module version, we need to choose one of the two to match. Herein, I choose the first one with "R_MIPS_HI16 _mcount". and In the kernel verion, without module tracing support, we just need to replace "jal _mcount" by "jal ftrace_caller" to do real tracing, and filter the tracing of some kernel functions via replacing it by a nop instruction. but as we have described before, the instruction "jal ftrace_caller" only left 32bit length for the address of ftrace_caller, it will fail when calling from the module space. so, herein, we must replace something else. the basic idea is loading the address of ftrace_caller to v1 via changing these two instructions: lui v1,0x0 addiu v1,v1,0 If we want to enable the tracing, we need to replace the above instructions to: lui v1, HI_16BIT_ftrace_caller addiu v1, v1, LOW_16BIT_ftrace_caller If we want to stop the tracing of the indicated kernel functions, we just need to replace the "jalr v1" to a nop instruction. but we need to replace two instructions and encode the above two instructions oursevles. Is there a simpler solution? Yes! Here it is, in this version, we put _mcount and ftrace_caller together, which means the address of _mcount and ftrace_caller is the same: _mcount: ftrace_caller: j ftrace_stub nop ...(do real tracing here)... ftrace_stub: jr ra move ra, at By default, the kernel functions call _mcount, and then jump to ftrace_stub and return. and when we want to do real tracing, we just need to remove that "j ftrace_stub", and it will run through the two "nop" instructions and then do the real tracing job. what about filtering job? we just need to do this: lui v1, hi_16bit_of_mcount <--> b 1f (0x10000004) addiu v1, v1, low_16bit_of_mcount move at, ra jalr v1 nop 1f: (rec->ip + 12) In linux-mips64, there will be some local symbols, whose name are prefixed by $L, which need to be filtered. thanks goes to Steven for writing the mips64-specific function_regex. In a conclusion, with RISC, things becomes easier with such a "stupid" trick, RISC is something like K.I.S.S, and also, there are lots of "simple" tricks in the whole ftrace support, thanks goes to Steven and the other folks for providing such a wonderful tracing framework! Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com> Cc: Nicholas Mc Guire <der.herr@hofr.at> Cc: zhangfx@lemote.com Cc: Wu Zhangjin <wuzhangjin@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Patchwork: http://patchwork.linux-mips.org/patch/675/ Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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