kernel.git/tools/perf/arch/powerpc, branch linux-3.18.y

perf powerpc: Fix callchain ip filtering

2018-09-26T06:33:56Z

[ Upstream commit c715fcfda5a08edabaa15508742be926b7ee51db ] For powerpc64, redundant entries in the callchain are filtered out by determining the state of the return address and the stack frame using DWARF debug information. For making these filtering decisions we must analyze the debug information for the location corresponding to the program counter value, i.e. the first entry in the callchain, and not the LR value; otherwise, perf may filter out either the second or the third entry in the callchain incorrectly. This can be observed on a powerpc64le system running Fedora 27 as shown below. Case 1 - Attaching a probe at inet_pton+0x8 (binary offset 0x15af28). Return address is still in LR and a new stack frame is not yet allocated. The LR value, i.e. the second entry, should not be filtered out. # objdump -d /usr/lib64/libc-2.26.so | less ... 000000000010eb10 : ... 10fa48: 78 bb e4 7e mr r4,r23 10fa4c: 0a 00 60 38 li r3,10 10fa50: d9 b4 04 48 bl 15af28 10fa54: 00 00 00 60 nop 10fa58: ac f4 ff 4b b 10ef04 ... 0000000000110450 : ... 1105a8: 54 00 ff 38 addi r7,r31,84 1105ac: 58 00 df 38 addi r6,r31,88 1105b0: 69 e5 ff 4b bl 10eb18 1105b4: 78 1b 71 7c mr r17,r3 1105b8: 50 01 7f e8 ld r3,336(r31) ... 000000000015af20 : 15af20: 0b 00 4c 3c addis r2,r12,11 15af24: e0 c1 42 38 addi r2,r2,-15904 15af28: a6 02 08 7c mflr r0 15af2c: f0 ff c1 fb std r30,-16(r1) 15af30: f8 ff e1 fb std r31,-8(r1) ... # perf probe -x /usr/lib64/libc-2.26.so -a inet_pton+0x8 # perf record -e probe_libc:inet_pton -g ping -6 -c 1 ::1 # perf script Before: ping 4507 [002] 514985.546540: probe_libc:inet_pton: (7fffa7dbaf28) 7fffa7dbaf28 __GI___inet_pton+0x8 (/usr/lib64/libc-2.26.so) 7fffa7d705b4 getaddrinfo+0x164 (/usr/lib64/libc-2.26.so) 13fb52d70 _init+0xbfc (/usr/bin/ping) 7fffa7c836a0 generic_start_main.isra.0+0x140 (/usr/lib64/libc-2.26.so) 7fffa7c83898 __libc_start_main+0xb8 (/usr/lib64/libc-2.26.so) 0 [unknown] ([unknown]) After: ping 4507 [002] 514985.546540: probe_libc:inet_pton: (7fffa7dbaf28) 7fffa7dbaf28 __GI___inet_pton+0x8 (/usr/lib64/libc-2.26.so) 7fffa7d6fa54 gaih_inet.constprop.7+0xf44 (/usr/lib64/libc-2.26.so) 7fffa7d705b4 getaddrinfo+0x164 (/usr/lib64/libc-2.26.so) 13fb52d70 _init+0xbfc (/usr/bin/ping) 7fffa7c836a0 generic_start_main.isra.0+0x140 (/usr/lib64/libc-2.26.so) 7fffa7c83898 __libc_start_main+0xb8 (/usr/lib64/libc-2.26.so) 0 [unknown] ([unknown]) Case 2 - Attaching a probe at _int_malloc+0x180 (binary offset 0x9cf10). Return address in still in LR and a new stack frame has already been allocated but not used. The caller's caller, i.e. the third entry, is invalid and should be filtered out and not the second one. # objdump -d /usr/lib64/libc-2.26.so | less ... 000000000009cd90 <_int_malloc>: 9cd90: 17 00 4c 3c addis r2,r12,23 9cd94: 70 a3 42 38 addi r2,r2,-23696 9cd98: 26 00 80 7d mfcr r12 9cd9c: f8 ff e1 fb std r31,-8(r1) 9cda0: 17 00 e4 3b addi r31,r4,23 9cda4: d8 ff 61 fb std r27,-40(r1) 9cda8: 78 23 9b 7c mr r27,r4 9cdac: 1f 00 bf 2b cmpldi cr7,r31,31 9cdb0: f0 ff c1 fb std r30,-16(r1) 9cdb4: b0 ff c1 fa std r22,-80(r1) 9cdb8: 78 1b 7e 7c mr r30,r3 9cdbc: 08 00 81 91 stw r12,8(r1) 9cdc0: 11 ff 21 f8 stdu r1,-240(r1) 9cdc4: 4c 01 9d 41 bgt cr7,9cf10 <_int_malloc+0x180> 9cdc8: 20 00 a4 2b cmpldi cr7,r4,32 ... 9cf08: 00 00 00 60 nop 9cf0c: 00 00 42 60 ori r2,r2,0 9cf10: e4 06 ff 7b rldicr r31,r31,0,59 9cf14: 40 f8 a4 7f cmpld cr7,r4,r31 9cf18: 68 05 9d 41 bgt cr7,9d480 <_int_malloc+0x6f0> ... 000000000009e3c0 : ... 9e420: 40 02 80 38 li r4,576 9e424: 78 fb e3 7f mr r3,r31 9e428: 71 e9 ff 4b bl 9cd98 <_int_malloc+0x8> 9e42c: 00 00 a3 2f cmpdi cr7,r3,0 9e430: 78 1b 7e 7c mr r30,r3 ... 000000000009f7a0 <__libc_malloc>: ... 9f8f8: 00 00 89 2f cmpwi cr7,r9,0 9f8fc: 1c ff 9e 40 bne cr7,9f818 <__libc_malloc+0x78> 9f900: c9 ea ff 4b bl 9e3c8 9f904: 00 00 00 60 nop 9f908: e8 90 22 e9 ld r9,-28440(r2) ... # perf probe -x /usr/lib64/libc-2.26.so -a _int_malloc+0x180 # perf record -e probe_libc:_int_malloc -g ./test-malloc # perf script Before: test-malloc 6554 [009] 515975.797403: probe_libc:_int_malloc: (7fffa6e6cf10) 7fffa6e6cf10 _int_malloc+0x180 (/usr/lib64/libc-2.26.so) 7fffa6dd0000 [unknown] (/usr/lib64/libc-2.26.so) 7fffa6e6f904 malloc+0x164 (/usr/lib64/libc-2.26.so) 7fffa6e6f9fc malloc+0x25c (/usr/lib64/libc-2.26.so) 100006b4 main+0x38 (/home/testuser/test-malloc) 7fffa6df36a0 generic_start_main.isra.0+0x140 (/usr/lib64/libc-2.26.so) 7fffa6df3898 __libc_start_main+0xb8 (/usr/lib64/libc-2.26.so) 0 [unknown] ([unknown]) After: test-malloc 6554 [009] 515975.797403: probe_libc:_int_malloc: (7fffa6e6cf10) 7fffa6e6cf10 _int_malloc+0x180 (/usr/lib64/libc-2.26.so) 7fffa6e6e42c tcache_init.part.4+0x6c (/usr/lib64/libc-2.26.so) 7fffa6e6f904 malloc+0x164 (/usr/lib64/libc-2.26.so) 7fffa6e6f9fc malloc+0x25c (/usr/lib64/libc-2.26.so) 100006b4 main+0x38 (/home/sandipan/test-malloc) 7fffa6df36a0 generic_start_main.isra.0+0x140 (/usr/lib64/libc-2.26.so) 7fffa6df3898 __libc_start_main+0xb8 (/usr/lib64/libc-2.26.so) 0 [unknown] ([unknown]) Signed-off-by: Sandipan Das Cc: Jiri Olsa Cc: Maynard Johnson Cc: Naveen N. Rao Cc: Ravi Bangoria Cc: Sukadev Bhattiprolu Fixes: a60335ba3298 ("perf tools powerpc: Adjust callchain based on DWARF debug info") Link: http://lkml.kernel.org/r/24bb726d91ed173aebc972ec3f41a2ef2249434e.1530724939.git.sandipan@linux.ibm.com Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

perf powerpc: Fix callchain ip filtering when return address is in a register

2018-09-26T06:33:56Z

[ Upstream commit 9068533e4f470daf2b0f29c71d865990acd8826e ] For powerpc64, perf will filter out the second entry in the callchain, i.e. the LR value, if the return address of the function corresponding to the probed location has already been saved on its caller's stack. The state of the return address is determined using debug information. At any point within a function, if the return address is already saved somewhere, a DWARF expression can tell us about its location. If the return address in still in LR only, no DWARF expression would exist. Typically, the instructions in a function's prologue first copy the LR value to R0 and then pushes R0 on to the stack. If LR has already been copied to R0 but R0 is yet to be pushed to the stack, we can still get a DWARF expression that says that the return address is in R0. This is indicating that getting a DWARF expression for the return address does not guarantee the fact that it has already been saved on the stack. This can be observed on a powerpc64le system running Fedora 27 as shown below. # objdump -d /usr/lib64/libc-2.26.so | less ... 000000000015af20 : 15af20: 0b 00 4c 3c addis r2,r12,11 15af24: e0 c1 42 38 addi r2,r2,-15904 15af28: a6 02 08 7c mflr r0 15af2c: f0 ff c1 fb std r30,-16(r1) 15af30: f8 ff e1 fb std r31,-8(r1) 15af34: 78 1b 7f 7c mr r31,r3 15af38: 78 23 83 7c mr r3,r4 15af3c: 78 2b be 7c mr r30,r5 15af40: 10 00 01 f8 std r0,16(r1) 15af44: c1 ff 21 f8 stdu r1,-64(r1) 15af48: 28 00 81 f8 std r4,40(r1) ... # readelf --debug-dump=frames-interp /usr/lib64/libc-2.26.so | less ... 00027024 0000000000000024 00027028 FDE cie=00000000 pc=000000000015af20..000000000015af88 LOC CFA r30 r31 ra 000000000015af20 r1+0 u u u 000000000015af34 r1+0 c-16 c-8 r0 000000000015af48 r1+64 c-16 c-8 c+16 000000000015af5c r1+0 c-16 c-8 c+16 000000000015af78 r1+0 u u ... # perf probe -x /usr/lib64/libc-2.26.so -a inet_pton+0x18 # perf record -e probe_libc:inet_pton -g ping -6 -c 1 ::1 # perf script Before: ping 2829 [005] 512917.460174: probe_libc:inet_pton: (7fff7e2baf38) 7fff7e2baf38 __GI___inet_pton+0x18 (/usr/lib64/libc-2.26.so) 7fff7e2705b4 getaddrinfo+0x164 (/usr/lib64/libc-2.26.so) 12f152d70 _init+0xbfc (/usr/bin/ping) 7fff7e1836a0 generic_start_main.isra.0+0x140 (/usr/lib64/libc-2.26.so) 7fff7e183898 __libc_start_main+0xb8 (/usr/lib64/libc-2.26.so) 0 [unknown] ([unknown]) After: ping 2829 [005] 512917.460174: probe_libc:inet_pton: (7fff7e2baf38) 7fff7e2baf38 __GI___inet_pton+0x18 (/usr/lib64/libc-2.26.so) 7fff7e26fa54 gaih_inet.constprop.7+0xf44 (/usr/lib64/libc-2.26.so) 7fff7e2705b4 getaddrinfo+0x164 (/usr/lib64/libc-2.26.so) 12f152d70 _init+0xbfc (/usr/bin/ping) 7fff7e1836a0 generic_start_main.isra.0+0x140 (/usr/lib64/libc-2.26.so) 7fff7e183898 __libc_start_main+0xb8 (/usr/lib64/libc-2.26.so) 0 [unknown] ([unknown]) Reported-by: Ravi Bangoria Signed-off-by: Sandipan Das Cc: Jiri Olsa Cc: Maynard Johnson Cc: Naveen N. Rao Cc: Ravi Bangoria Cc: Sukadev Bhattiprolu Link: http://lkml.kernel.org/r/66e848a7bdf2d43b39210a705ff6d828a0865661.1530724939.git.sandipan@linux.ibm.com Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

perf report powerpc: Fix crash if callchain is empty

2018-08-28T05:21:35Z

[ Upstream commit 143c99f6ac6812d23254e80844d6e34be897d3e1 ] For some cases, the callchain provided by the kernel may be empty. So, the callchain ip filtering code will cause a crash if we do not check whether the struct ip_callchain pointer is NULL before accessing any members. This can be observed on a powerpc64le system running Fedora 27 as shown below. # perf record -b -e cycles:u ls Before: # perf report --branch-history perf: Segmentation fault -------- backtrace -------- perf[0x1027615c] linux-vdso64.so.1(__kernel_sigtramp_rt64+0x0)[0x7fff856304d8] perf(arch_skip_callchain_idx+0x44)[0x10257c58] perf[0x1017f2e4] perf(thread__resolve_callchain+0x124)[0x1017ff5c] perf(sample__resolve_callchain+0xf0)[0x10172788] ... After: # perf report --branch-history Samples: 25 of event 'cycles:u', Event count (approx.): 2306870 Overhead Source:Line Symbol Shared Object + 11.60% _init+35736 [.] _init ls + 9.84% strcoll_l.c:137 [.] __strcoll_l libc-2.26.so + 9.16% memcpy.S:175 [.] __memcpy_power7 libc-2.26.so + 9.01% gconv_charset.h:54 [.] _nl_find_locale libc-2.26.so + 8.87% dl-addr.c:52 [.] _dl_addr libc-2.26.so + 8.83% _init+236 [.] _init ls ... Reported-by: Ravi Bangoria Signed-off-by: Sandipan Das Acked-by: Ravi Bangoria Cc: Jiri Olsa Cc: Naveen N. Rao Cc: Sukadev Bhattiprolu Link: http://lkml.kernel.org/r/20180611104049.11048-1-sandipan@linux.ibm.com Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

perf tools powerpc: Fix build issue when DWARF support is disabled

2014-09-17T20:08:07Z

The powerpc skip callchain code uses DWARF, so we must disable it if DWARF is disabled. Signed-off-by: Anton Blanchard Cc: Ingo Molnar Cc: Michael Ellerman Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Sukadev Bhattiprolu Link: http://lkml.kernel.org/r/20140825182506.2be6512d@kryten Signed-off-by: Arnaldo Carvalho de Melo

perf tools powerpc: Explicitly include util/debug.h

2014-08-20T11:29:10Z

Looks like util/debug.h was indirectly included before and is no longer included now. pr_debug is left undefined and the build of perf tool fails on Powerpc. Explicitly include util/debug.h. Signed-off-by: Sukadev Bhattiprolu Acked-by: Jiri Olsa Cc: Jiri Olsa Cc: Michael Ellerman Link: http://lkml.kernel.org/r/20140807072700.GA17623@us.ibm.com Signed-off-by: Arnaldo Carvalho de Melo

perf powerpc: Include util/util.h and remove stringify macros

2014-07-24T14:00:39Z

The stringify macros are defined in tools/perf/util/util.h and don't need to be redfined specfiically for powerpc. Signed-off-by: Sukadev Bhattiprolu Cc: Andi Kleen Cc: Jiri Olsa Cc: Michael Ellerman Link: http://lkml.kernel.org/r/20140724074718.GB18829@us.ibm.com Signed-off-by: Arnaldo Carvalho de Melo

perf tools powerpc: Adjust callchain based on DWARF debug info

2014-06-27T09:14:51Z

When saving the callchain on Power, the kernel conservatively saves excess entries in the callchain. A few of these entries are needed in some cases but not others. We should use the DWARF debug information to determine when the entries are needed. Eg: the value in the link register (LR) is needed only when it holds the return address of a function. At other times it must be ignored. If the unnecessary entries are not ignored, we end up with duplicate arcs in the call-graphs. Use the DWARF debug information to determine if any callchain entries should be ignored when building call-graphs. Callgraph before the patch: 14.67% 2234 sprintft libc-2.18.so [.] __random | --- __random | |--61.12%-- __random | | | |--97.15%-- rand | | do_my_sprintf | | main | | generic_start_main.isra.0 | | __libc_start_main | | 0x0 | | | --2.85%-- do_my_sprintf | main | generic_start_main.isra.0 | __libc_start_main | 0x0 | --38.88%-- rand | |--94.01%-- rand | do_my_sprintf | main | generic_start_main.isra.0 | __libc_start_main | 0x0 | --5.99%-- do_my_sprintf main generic_start_main.isra.0 __libc_start_main 0x0 Callgraph after the patch: 14.67% 2234 sprintft libc-2.18.so [.] __random | --- __random | |--95.93%-- rand | do_my_sprintf | main | generic_start_main.isra.0 | __libc_start_main | 0x0 | --4.07%-- do_my_sprintf main generic_start_main.isra.0 __libc_start_main 0x0 TODO: For split-debug info objects like glibc, we can only determine the call-frame-address only when both .eh_frame and .debug_info sections are available. We should be able to determin the CFA even without the .eh_frame section. Fix suggested by Anton Blanchard. Thanks to valuable input on DWARF debug information from Ulrich Weigand. Reported-by: Maynard Johnson Tested-by: Maynard Johnson Signed-off-by: Sukadev Bhattiprolu Link: http://lkml.kernel.org/r/20140625154903.GA29607@us.ibm.com Signed-off-by: Jiri Olsa

perf tools: Fix build on non-glibc systems due to libio.h absence

2013-03-15T16:05:13Z

Including libio.h causes build failures on uClibc systems (which lack libio.h). It appears that libio.h was only included to pull in a definition for NULL, so it has been replaced by stddef.h. On powerpc, libio.h was conditionally included, but could be removed completely as it is unneeded. Also, the included of stdlib.h was changed to stddef.h (as again, only NULL is needed). Signed-off-by: Cody P Schafer Cc: Ingo Molnar Cc: Paul Mackerras Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1363300074-26288-1-git-send-email-cody@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Use scnprintf where applicable

2012-03-14T15:36:19Z

Several places were expecting that the value returned was the number of characters printed, not what would be printed if there was space. Fix it by using the scnprintf and vscnprintf variants we inherited from the kernel sources. Some corner cases where the number of printed characters were not accounted were fixed too. Reported-by: Anton Blanchard Cc: Anton Blanchard Cc: Eric B Munson Cc: David Ahern Cc: Frederic Weisbecker Cc: Mike Galbraith Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Yanmin Zhang Cc: stable@kernel.org Link: http://lkml.kernel.org/n/tip-kwxo2eh29cxmd8ilixi2005x@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf/powerpc: Fix build for PowerPC with uclibc toolchains

2011-11-25T03:11:27Z

libio.h is not provided by uClibc, in order to be able to test the definition of __UCLIBC__ we need to include stdlib.h, which also includes stddef.h, providing the definition of 'NULL'. Signed-off-by: Florian Fainelli Signed-off-by: Benjamin Herrenschmidt