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Re: [PATCH 2/2] perf ppc64le: Fix probe location when using DWARF

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  Re: [PATCH 2/2] perf ppc64le: Fix probe location when using DWARF Anton Blanchard <anton@samba.org> - 2016-08-11 02:00 +0200
    Re: [PATCH 2/2] perf ppc64le: Fix probe location when using DWARF Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com> - 2016-08-11 06:40 +0200
      Re: [PATCH 2/2] perf ppc64le: Fix probe location when using DWARF Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-08-11 14:00 +0200
        Re: [PATCH 2/2] perf ppc64le: Fix probe location when using DWARF Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com> - 2016-08-11 15:30 +0200
          Re: [PATCH 2/2] perf ppc64le: Fix probe location when using DWARF Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-08-11 16:50 +0200
            Re: [PATCH 2/2] perf ppc64le: Fix probe location when using DWARF Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-08-11 19:50 +0200
        Re: [PATCH 2/2] perf ppc64le: Fix probe location when using DWARF Anton Blanchard <anton@samba.org> - 2016-08-12 08:10 +0200
          Re: [PATCH 2/2] perf ppc64le: Fix probe location when using DWARF Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-08-12 15:10 +0200
      [tip:perf/urgent] perf ppc64le: Fix build failure when libelf is  not present tip-bot for Ravi Bangoria <tipbot@zytor.com> - 2016-08-16 20:20 +0200
    Re: [PATCH 2/2] perf ppc64le: Fix probe location when using DWARF Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-08-11 17:50 +0200

#1460101 — Re: [PATCH 2/2] perf ppc64le: Fix probe location when using DWARF

Hi,

> Powerpc has Global Entry Point and Local Entry Point for functions.
> LEP catches call from both the GEP and the LEP. Symbol table of ELF
> contains GEP and Offset from which we can calculate LEP, but debuginfo
> does not have LEP info.
> 
> Currently, perf prioritize symbol table over dwarf to probe on LEP
> for ppc64le. But when user tries to probe with function parameter,
> we fall back to using dwarf(i.e. GEP) and when function called via
> LEP, probe will never hit.

This patch causes a build failure for me on ppc64le:

libperf.a(libperf-in.o): In function `arch__post_process_probe_trace_events':

tools/perf/arch/powerpc/util/sym-handling.c:109: undefined reference to `get_target_map'

Anton

> For example:
>   $ objdump -d vmlinux
>     ...
>     do_sys_open():
>     c0000000002eb4a0:       e8 00 4c 3c     addis   r2,r12,232
>     c0000000002eb4a4:       60 00 42 38     addi    r2,r2,96
>     c0000000002eb4a8:       a6 02 08 7c     mflr    r0
>     c0000000002eb4ac:       d0 ff 41 fb     std     r26,-48(r1)
> 
>   $ sudo ./perf probe do_sys_open
>   $ sudo cat /sys/kernel/debug/tracing/kprobe_events
>     p:probe/do_sys_open _text+3060904
> 
>   $ sudo ./perf probe 'do_sys_open filename:string'
>   $ sudo cat /sys/kernel/debug/tracing/kprobe_events
>     p:probe/do_sys_open _text+3060896 filename_string=+0(%gpr4):string
> 
> For second case, perf probed on GEP. So when function will be called
> via LEP, probe won't hit.
> 
>   $ sudo ./perf record -a -e probe:do_sys_open ls
>     [ perf record: Woken up 1 times to write data ]
>     [ perf record: Captured and wrote 0.195 MB perf.data ]
> 
> To resolve this issue, let's not prioritize symbol table, let perf
> decide what it wants to use. Perf is already converting GEP to LEP
> when it uses symbol table. When perf uses debuginfo, let it find
> LEP offset form symbol table. This way we fall back to probe on LEP
> for all cases.
> 
> After patch:
>   $ sudo ./perf probe 'do_sys_open filename:string'
>   $ sudo cat /sys/kernel/debug/tracing/kprobe_events
>     p:probe/do_sys_open _text+3060904 filename_string=+0(%gpr4):string
> 
>   $ sudo ./perf record -a -e probe:do_sys_open ls
>     [ perf record: Woken up 1 times to write data ]
>     [ perf record: Captured and wrote 0.197 MB perf.data (11 samples)
> ]
> 
> Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
> ---
>  tools/perf/arch/powerpc/util/sym-handling.c | 27
> +++++++++++++++++---- tools/perf/util/probe-event.c               |
> 37 ++++++++++++++++-------------
> tools/perf/util/probe-event.h               |  6 ++++- 3 files
> changed, 49 insertions(+), 21 deletions(-)
> 
> diff --git a/tools/perf/arch/powerpc/util/sym-handling.c
> b/tools/perf/arch/powerpc/util/sym-handling.c index c6d0f91..8d4dc97
> 100644 --- a/tools/perf/arch/powerpc/util/sym-handling.c
> +++ b/tools/perf/arch/powerpc/util/sym-handling.c
> @@ -54,10 +54,6 @@ int arch__compare_symbol_names(const char *namea,
> const char *nameb) #endif
>  
>  #if defined(_CALL_ELF) && _CALL_ELF == 2
> -bool arch__prefers_symtab(void)
> -{
> -	return true;
> -}
>  
>  #ifdef HAVE_LIBELF_SUPPORT
>  void arch__sym_update(struct symbol *s, GElf_Sym *sym)
> @@ -100,4 +96,27 @@ void arch__fix_tev_from_maps(struct
> perf_probe_event *pev, tev->point.offset += lep_offset;
>  	}
>  }
> +
> +void arch__post_process_probe_trace_events(struct perf_probe_event
> *pev,
> +					   int ntevs)
> +{
> +	struct probe_trace_event *tev;
> +	struct map *map;
> +	struct symbol *sym = NULL;
> +	struct rb_node *tmp;
> +	int i = 0;
> +
> +	map = get_target_map(pev->target, pev->uprobes);
> +	if (!map || map__load(map, NULL) < 0)
> +		return;
> +
> +	for (i = 0; i < ntevs; i++) {
> +		tev = &pev->tevs[i];
> +		map__for_each_symbol(map, sym, tmp) {
> +			if (map->unmap_ip(map, sym->start) ==
> tev->point.address)
> +				arch__fix_tev_from_maps(pev, tev,
> map, sym);
> +		}
> +	}
> +}
> +
>  #endif
> diff --git a/tools/perf/util/probe-event.c
> b/tools/perf/util/probe-event.c index 4e215e7..5efa535 100644
> --- a/tools/perf/util/probe-event.c
> +++ b/tools/perf/util/probe-event.c
> @@ -178,7 +178,7 @@ static struct map *kernel_get_module_map(const
> char *module) return NULL;
>  }
>  
> -static struct map *get_target_map(const char *target, bool user)
> +struct map *get_target_map(const char *target, bool user)
>  {
>  	/* Init maps of given executable or kernel */
>  	if (user)
> @@ -703,19 +703,32 @@ post_process_kernel_probe_trace_events(struct
> probe_trace_event *tevs, return skipped;
>  }
>  
> +void __weak
> +arch__post_process_probe_trace_events(struct perf_probe_event *pev
> __maybe_unused,
> +				      int ntevs __maybe_unused)
> +{
> +}
> +
>  /* Post processing the probe events */
> -static int post_process_probe_trace_events(struct probe_trace_event
> *tevs, +static int post_process_probe_trace_events(struct
> perf_probe_event *pev,
> +					   struct probe_trace_event
> *tevs, int ntevs, const char *module,
>  					   bool uprobe)
>  {
> -	if (uprobe)
> -		return add_exec_to_probe_trace_events(tevs, ntevs,
> module);
> +	int ret;
>  
> -	if (module)
> +	if (uprobe)
> +		ret = add_exec_to_probe_trace_events(tevs, ntevs,
> module);
> +	else if (module)
>  		/* Currently ref_reloc_sym based probe is not for
> drivers */
> -		return add_module_to_probe_trace_events(tevs, ntevs,
> module);
> +		ret = add_module_to_probe_trace_events(tevs, ntevs,
> module);
> +	else
> +		ret = post_process_kernel_probe_trace_events(tevs,
> ntevs); 
> -	return post_process_kernel_probe_trace_events(tevs, ntevs);
> +	if (ret >= 0)
> +		arch__post_process_probe_trace_events(pev, ntevs);
> +
> +	return ret;
>  }
>  
>  /* Try to find perf_probe_event with debuginfo */
> @@ -756,7 +769,7 @@ static int try_to_find_probe_trace_events(struct
> perf_probe_event *pev, 
>  	if (ntevs > 0) {	/* Succeeded to find trace events */
>  		pr_debug("Found %d probe_trace_events.\n", ntevs);
> -		ret = post_process_probe_trace_events(*tevs, ntevs,
> +		ret = post_process_probe_trace_events(pev, *tevs,
> ntevs, pev->target, pev->uprobes);
>  		if (ret < 0 || ret == ntevs) {
>  			clear_probe_trace_events(*tevs, ntevs);
> @@ -2943,8 +2956,6 @@ errout:
>  	return err;
>  }
>  
> -bool __weak arch__prefers_symtab(void) { return false; }
> -
>  /* Concatinate two arrays */
>  static void *memcat(void *a, size_t sz_a, void *b, size_t sz_b)
>  {
> @@ -3165,12 +3176,6 @@ static int
> convert_to_probe_trace_events(struct perf_probe_event *pev, if (ret >
> 0 || pev->sdt)	/* SDT can be found only in the cache */ return
> ret == 0 ? -ENOENT : ret; /* Found in probe cache */ 
> -	if (arch__prefers_symtab()
> && !perf_probe_event_need_dwarf(pev)) {
> -		ret = find_probe_trace_events_from_map(pev, tevs);
> -		if (ret > 0)
> -			return ret; /* Found in symbol table */
> -	}
> -
>  	/* Convert perf_probe_event with debuginfo */
>  	ret = try_to_find_probe_trace_events(pev, tevs);
>  	if (ret != 0)
> diff --git a/tools/perf/util/probe-event.h
> b/tools/perf/util/probe-event.h index e18ea9f..f4f45db 100644
> --- a/tools/perf/util/probe-event.h
> +++ b/tools/perf/util/probe-event.h
> @@ -158,7 +158,6 @@ int show_line_range(struct line_range *lr, const
> char *module, bool user); int show_available_vars(struct
> perf_probe_event *pevs, int npevs, struct strfilter *filter);
>  int show_available_funcs(const char *module, struct strfilter
> *filter, bool user); -bool arch__prefers_symtab(void);
>  void arch__fix_tev_from_maps(struct perf_probe_event *pev,
>  			     struct probe_trace_event *tev, struct
> map *map, struct symbol *sym);
> @@ -173,4 +172,9 @@ int e_snprintf(char *str, size_t size, const char
> *format, ...) int copy_to_probe_trace_arg(struct probe_trace_arg
> *tvar, struct perf_probe_arg *pvar);
>  
> +struct map *get_target_map(const char *target, bool user);
> +
> +void arch__post_process_probe_trace_events(struct perf_probe_event
> *pev,
> +					   int ntevs);
> +
>  #endif /*_PROBE_EVENT_H */

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#1460165

On Thursday 11 August 2016 05:24 AM, Anton Blanchard wrote:
> Hi,
>
>> Powerpc has Global Entry Point and Local Entry Point for functions.
>> LEP catches call from both the GEP and the LEP. Symbol table of ELF
>> contains GEP and Offset from which we can calculate LEP, but debuginfo
>> does not have LEP info.
>>
>> Currently, perf prioritize symbol table over dwarf to probe on LEP
>> for ppc64le. But when user tries to probe with function parameter,
>> we fall back to using dwarf(i.e. GEP) and when function called via
>> LEP, probe will never hit.
> This patch causes a build failure for me on ppc64le:
>
> libperf.a(libperf-in.o): In function `arch__post_process_probe_trace_events':
>
> tools/perf/arch/powerpc/util/sym-handling.c:109: undefined reference to `get_target_map'

Thanks Anton. Sorry, I should have caught that.

@Arnaldo, Can you please pick this up. I've prepared this on top of 
acme/perf/core.


 From 89c977ae9c3ae35c78b16cddabcf2b01d3cf5cc8 Mon Sep 17 00:00:00 2001
From: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Date: Wed, 10 Aug 2016 23:13:45 -0500
Subject: [PATCH] perf ppc64le: Fix build failure when no dwarf support

Fix perf build failure on ppc64le because of Commit 99e608b5954c ("perf
probe ppc64le: Fix probe location when using DWARF")

Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
---
  tools/perf/arch/powerpc/util/sym-handling.c | 2 ++
  1 file changed, 2 insertions(+)

diff --git a/tools/perf/arch/powerpc/util/sym-handling.c 
b/tools/perf/arch/powerpc/util/sym-handling.c
index 8d4dc97..c27a51a 100644
--- a/tools/perf/arch/powerpc/util/sym-handling.c
+++ b/tools/perf/arch/powerpc/util/sym-handling.c
@@ -97,6 +97,7 @@ void arch__fix_tev_from_maps(struct perf_probe_event *pev,
         }
  }

+#ifdef HAVE_LIBELF_SUPPORT
  void arch__post_process_probe_trace_events(struct perf_probe_event *pev,
                                            int ntevs)
  {
@@ -118,5 +119,6 @@ void arch__post_process_probe_trace_events(struct 
perf_probe_event *pev,
                 }
         }
  }
+#endif

  #endif
-- 
2.7.4

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#1460440

Em Thu, Aug 11, 2016 at 10:01:04AM +0530, Ravi Bangoria escreveu:
> 
> 
> On Thursday 11 August 2016 05:24 AM, Anton Blanchard wrote:
> > Hi,
> > 
> > > Powerpc has Global Entry Point and Local Entry Point for functions.
> > > LEP catches call from both the GEP and the LEP. Symbol table of ELF
> > > contains GEP and Offset from which we can calculate LEP, but debuginfo
> > > does not have LEP info.
> > > 
> > > Currently, perf prioritize symbol table over dwarf to probe on LEP
> > > for ppc64le. But when user tries to probe with function parameter,
> > > we fall back to using dwarf(i.e. GEP) and when function called via
> > > LEP, probe will never hit.
> > This patch causes a build failure for me on ppc64le:
> > 
> > libperf.a(libperf-in.o): In function `arch__post_process_probe_trace_events':
> > 
> > tools/perf/arch/powerpc/util/sym-handling.c:109: undefined reference to `get_target_map'
> 
> Thanks Anton. Sorry, I should have caught that.
> 
> @Arnaldo, Can you please pick this up. I've prepared this on top of
> acme/perf/core.
> 
> 
> From 89c977ae9c3ae35c78b16cddabcf2b01d3cf5cc8 Mon Sep 17 00:00:00 2001
> From: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
> Date: Wed, 10 Aug 2016 23:13:45 -0500
> Subject: [PATCH] perf ppc64le: Fix build failure when no dwarf support
> 
> Fix perf build failure on ppc64le because of Commit 99e608b5954c ("perf
> probe ppc64le: Fix probe location when using DWARF")

Can you please provide a better explanation? I had to look at the patch
to understand what it was fixing, and then the patch adds LIBELF_SUPPORT
ifdefs while the patch description, talks about DWARF.

Anyway, Anton, does this fix the problem for you?

- Arnaldo
 
> Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
> ---
>  tools/perf/arch/powerpc/util/sym-handling.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/tools/perf/arch/powerpc/util/sym-handling.c
> b/tools/perf/arch/powerpc/util/sym-handling.c
> index 8d4dc97..c27a51a 100644
> --- a/tools/perf/arch/powerpc/util/sym-handling.c
> +++ b/tools/perf/arch/powerpc/util/sym-handling.c
> @@ -97,6 +97,7 @@ void arch__fix_tev_from_maps(struct perf_probe_event *pev,
>         }
>  }
> 
> +#ifdef HAVE_LIBELF_SUPPORT
>  void arch__post_process_probe_trace_events(struct perf_probe_event *pev,
>                                            int ntevs)
>  {
> @@ -118,5 +119,6 @@ void arch__post_process_probe_trace_events(struct
> perf_probe_event *pev,
>                 }
>         }
>  }
> +#endif
> 
>  #endif
> -- 
> 2.7.4

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#1460521

On Thursday 11 August 2016 05:20 PM, Arnaldo Carvalho de Melo wrote:
> Em Thu, Aug 11, 2016 at 10:01:04AM +0530, Ravi Bangoria escreveu:
>>
>> On Thursday 11 August 2016 05:24 AM, Anton Blanchard wrote:
>>> Hi,
>>>
>>>> Powerpc has Global Entry Point and Local Entry Point for functions.
>>>> LEP catches call from both the GEP and the LEP. Symbol table of ELF
>>>> contains GEP and Offset from which we can calculate LEP, but debuginfo
>>>> does not have LEP info.
>>>>
>>>> Currently, perf prioritize symbol table over dwarf to probe on LEP
>>>> for ppc64le. But when user tries to probe with function parameter,
>>>> we fall back to using dwarf(i.e. GEP) and when function called via
>>>> LEP, probe will never hit.
>>> This patch causes a build failure for me on ppc64le:
>>>
>>> libperf.a(libperf-in.o): In function `arch__post_process_probe_trace_events':
>>>
>>> tools/perf/arch/powerpc/util/sym-handling.c:109: undefined reference to `get_target_map'
>> Thanks Anton. Sorry, I should have caught that.
>>
>> @Arnaldo, Can you please pick this up. I've prepared this on top of
>> acme/perf/core.
>>
>>
>>  From 89c977ae9c3ae35c78b16cddabcf2b01d3cf5cc8 Mon Sep 17 00:00:00 2001
>> From: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
>> Date: Wed, 10 Aug 2016 23:13:45 -0500
>> Subject: [PATCH] perf ppc64le: Fix build failure when no dwarf support
>>
>> Fix perf build failure on ppc64le because of Commit 99e608b5954c ("perf
>> probe ppc64le: Fix probe location when using DWARF")
> Can you please provide a better explanation? I had to look at the patch
> to understand what it was fixing, and then the patch adds LIBELF_SUPPORT
> ifdefs while the patch description, talks about DWARF.

Yes. Explanation could have been better. Apologies for that.

arch__post_process_probe_trace_events() calls get_target_map() to prepare
symbol table. get_target_map() is defined inside util/probe-event.c.

probe-event.c will only get included in perf binary if CONFIG_LIBELF is set.
Hence arch__post_process_probe_trace_events() needs to be defined inside
#ifdef HAVE_LIBELF_SUPPORT to solve compilation error.

Please let me know if any doubts.

Thanks,
Ravi

> Anyway, Anton, does this fix the problem for you?
>
> - Arnaldo
>
>> Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
>> ---
>>   tools/perf/arch/powerpc/util/sym-handling.c | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/tools/perf/arch/powerpc/util/sym-handling.c
>> b/tools/perf/arch/powerpc/util/sym-handling.c
>> index 8d4dc97..c27a51a 100644
>> --- a/tools/perf/arch/powerpc/util/sym-handling.c
>> +++ b/tools/perf/arch/powerpc/util/sym-handling.c
>> @@ -97,6 +97,7 @@ void arch__fix_tev_from_maps(struct perf_probe_event *pev,
>>          }
>>   }
>>
>> +#ifdef HAVE_LIBELF_SUPPORT
>>   void arch__post_process_probe_trace_events(struct perf_probe_event *pev,
>>                                             int ntevs)
>>   {
>> @@ -118,5 +119,6 @@ void arch__post_process_probe_trace_events(struct
>> perf_probe_event *pev,
>>                  }
>>          }
>>   }
>> +#endif
>>
>>   #endif
>> -- 
>> 2.7.4

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#1460584

Em Thu, Aug 11, 2016 at 06:51:39PM +0530, Ravi Bangoria escreveu:
> 
> 
> On Thursday 11 August 2016 05:20 PM, Arnaldo Carvalho de Melo wrote:
> > Em Thu, Aug 11, 2016 at 10:01:04AM +0530, Ravi Bangoria escreveu:
> > > 
> > > On Thursday 11 August 2016 05:24 AM, Anton Blanchard wrote:
> > > > Hi,
> > > > 
> > > > > Powerpc has Global Entry Point and Local Entry Point for functions.
> > > > > LEP catches call from both the GEP and the LEP. Symbol table of ELF
> > > > > contains GEP and Offset from which we can calculate LEP, but debuginfo
> > > > > does not have LEP info.
> > > > > 
> > > > > Currently, perf prioritize symbol table over dwarf to probe on LEP
> > > > > for ppc64le. But when user tries to probe with function parameter,
> > > > > we fall back to using dwarf(i.e. GEP) and when function called via
> > > > > LEP, probe will never hit.
> > > > This patch causes a build failure for me on ppc64le:
> > > > 
> > > > libperf.a(libperf-in.o): In function `arch__post_process_probe_trace_events':
> > > > 
> > > > tools/perf/arch/powerpc/util/sym-handling.c:109: undefined reference to `get_target_map'
> > > Thanks Anton. Sorry, I should have caught that.
> > > 
> > > @Arnaldo, Can you please pick this up. I've prepared this on top of
> > > acme/perf/core.
> > > 
> > > 
> > >  From 89c977ae9c3ae35c78b16cddabcf2b01d3cf5cc8 Mon Sep 17 00:00:00 2001
> > > From: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
> > > Date: Wed, 10 Aug 2016 23:13:45 -0500
> > > Subject: [PATCH] perf ppc64le: Fix build failure when no dwarf support
> > > 
> > > Fix perf build failure on ppc64le because of Commit 99e608b5954c ("perf
> > > probe ppc64le: Fix probe location when using DWARF")
> > Can you please provide a better explanation? I had to look at the patch
> > to understand what it was fixing, and then the patch adds LIBELF_SUPPORT
> > ifdefs while the patch description, talks about DWARF.
> 
> Yes. Explanation could have been better. Apologies for that.
> 
> arch__post_process_probe_trace_events() calls get_target_map() to prepare
> symbol table. get_target_map() is defined inside util/probe-event.c.
> 
> probe-event.c will only get included in perf binary if CONFIG_LIBELF is set.
> Hence arch__post_process_probe_trace_events() needs to be defined inside
> #ifdef HAVE_LIBELF_SUPPORT to solve compilation error.
> 
> Please let me know if any doubts.

Thanks, that is better, will add this there.

- Arnaldo

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#1460715

Em Thu, Aug 11, 2016 at 11:49:00AM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Thu, Aug 11, 2016 at 06:51:39PM +0530, Ravi Bangoria escreveu:
> > On Thursday 11 August 2016 05:20 PM, Arnaldo Carvalho de Melo wrote:
> > > Can you please provide a better explanation? I had to look at the patch
> > > to understand what it was fixing, and then the patch adds LIBELF_SUPPORT
> > > ifdefs while the patch description, talks about DWARF.

> > Yes. Explanation could have been better. Apologies for that.

> > arch__post_process_probe_trace_events() calls get_target_map() to prepare
> > symbol table. get_target_map() is defined inside util/probe-event.c.

> > probe-event.c will only get included in perf binary if CONFIG_LIBELF is set.
> > Hence arch__post_process_probe_trace_events() needs to be defined inside
> > #ifdef HAVE_LIBELF_SUPPORT to solve compilation error.
 
> > Please let me know if any doubts.
 
> Thanks, that is better, will add this there.

But the patch his mangled, you use:

User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101
        Thunderbird/38.5.1

Please read Documentation/email-clients.txt, there are ways to fix the
sending of patches.

I fixed it up this time, there were two instances like:

[acme@jouet linux]$ patch -p1 < /wb/1.patch 
patching file tools/perf/arch/powerpc/util/sym-handling.c
patch: **** malformed patch at line 33: @@ -118,5 +119,6 @@ void arch__post_process_probe_trace_events(struct 

it breaks down long lines ;-\

[acme@jouet linux]$

- Arnaldo

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#1460963

Hi Arnaldo,

> Anyway, Anton, does this fix the problem for you?

Yes it does, thanks!

Anton

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#1461162

Em Fri, Aug 12, 2016 at 04:06:55PM +1000, Anton Blanchard escreveu:
> Hi Arnaldo,
> 
> > Anyway, Anton, does this fix the problem for you?
> 
> Yes it does, thanks!

Thanks, adding a Tested-by: you.

- Arnaldo

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#1463987 — [tip:perf/urgent] perf ppc64le: Fix build failure when libelf is not present

Commit-ID:  f046f3df665361d2f89e660f8c79ba164069f02a
Gitweb:     http://git.kernel.org/tip/f046f3df665361d2f89e660f8c79ba164069f02a
Author:     Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
AuthorDate: Thu, 11 Aug 2016 14:43:59 -0300
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Fri, 12 Aug 2016 14:39:48 -0300

perf ppc64le: Fix build failure when libelf is not present

arch__post_process_probe_trace_events() calls get_target_map() to
prepare symbol table. get_target_map() is defined inside
util/probe-event.c.

probe-event.c will only get included in perf binary if CONFIG_LIBELF is
set.  Hence arch__post_process_probe_trace_events() needs to be defined
inside #ifdef HAVE_LIBELF_SUPPORT to solve compilation error.

Reported-and-Tested-by: Anton Blanchard <anton@samba.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/57ABFF88.8030905@linux.vnet.ibm.com
[ Thunderbird MUA mangled it, fix that ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/arch/powerpc/util/sym-handling.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/perf/arch/powerpc/util/sym-handling.c b/tools/perf/arch/powerpc/util/sym-handling.c
index 8d4dc97..35745a7 100644
--- a/tools/perf/arch/powerpc/util/sym-handling.c
+++ b/tools/perf/arch/powerpc/util/sym-handling.c
@@ -97,6 +97,7 @@ void arch__fix_tev_from_maps(struct perf_probe_event *pev,
 	}
 }
 
+#ifdef HAVE_LIBELF_SUPPORT
 void arch__post_process_probe_trace_events(struct perf_probe_event *pev,
 					   int ntevs)
 {
@@ -118,5 +119,6 @@ void arch__post_process_probe_trace_events(struct perf_probe_event *pev,
 		}
 	}
 }
+#endif /* HAVE_LIBELF_SUPPORT */
 
 #endif

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#1460626

Em Thu, Aug 11, 2016 at 09:54:57AM +1000, Anton Blanchard escreveu:
> Hi,
> 
> > Powerpc has Global Entry Point and Local Entry Point for functions.
> > LEP catches call from both the GEP and the LEP. Symbol table of ELF
> > contains GEP and Offset from which we can calculate LEP, but debuginfo
> > does not have LEP info.
> > 
> > Currently, perf prioritize symbol table over dwarf to probe on LEP
> > for ppc64le. But when user tries to probe with function parameter,
> > we fall back to using dwarf(i.e. GEP) and when function called via
> > LEP, probe will never hit.
> 
> This patch causes a build failure for me on ppc64le:
> 
> libperf.a(libperf-in.o): In function `arch__post_process_probe_trace_events':
> 
> tools/perf/arch/powerpc/util/sym-handling.c:109: undefined reference to `get_target_map'

Humm, he sent a patch, I'm applying it, but I'm trying to figure out why
this wasn't catched by my cross compiling container :-\

Complete log and:

  CC       /tmp/build/perf/util/probe-event.o

Because:

...                        libelf: [ on  ]

So I would have to build with NO_LIBELF=1? /me tries... further proof I need to
build with 'make -C tools/perf build-test' for all the arches, that will test, among
other combos, with NO_LIBELF=1 and without :-\

# docker run --entrypoint=/bin/bash -v /home/acme/git:/git:Z --rm -ti docker.io/acmel/linux-perf-tools-build-ubuntu:16.04-x-powerpc64el
perfbuilder@74bca30d5b61:/$ make NO_LIBELF=1 ARCH=powerpc CROSS_COMPILE=powerpc64le-linux-gnu- -C /git/linux/tools/perf O=/tmp/build/perf
<SNIP>
  LINK     /tmp/build/perf/perf
/tmp/build/perf/libperf.a(libperf-in.o): In function `arch__post_process_probe_trace_events':
/git/linux/tools/perf/arch/powerpc/util/sym-handling.c:109: undefined reference to `get_target_map'
collect2: error: ld returned 1 exit status
Makefile.perf:435: recipe for target '/tmp/build/perf/perf' failed
make[1]: *** [/tmp/build/perf/perf] Error 1
Makefile:68: recipe for target 'all' failed
make: *** [all] Error 2
make: Leaving directory '/git/linux/tools/perf'
perfbuilder@74bca30d5b61:/$

Ok, reproduced, will add the NO_LIBELF=1 to the regular set of tests for ppc64le.

- Arnaldo

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