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perf probe arm64: Fix symbol fixup issues due to ELF type

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On an arm64 machine running a CONFIG_RANDOMIZE_BASE=y kernel, perf
kernel symbol resolution fails.  Debugging saw symsrc_init calling the
default elf__needs_adjust_symbols() where checks for an ET_DYN (3)
ehdr.e_type failed when they should have succeeded.

Fix by adopting powerpc version of the weak elf__needs_adjust_symbols()
function, as done in commit d233209833 ("perf probe ppc: Fix symbol
fixup issues due to ELF type").

Prior to this patch, perf test 1 would fail:

  $ sudo oldperf test -v 1 |& head
   1: vmlinux symtab matches kallsyms                       :
  test child forked, pid 33374
  Looking at the vmlinux_path (8 entries long)
  Using /usr/lib/debug/boot/vmlinux for symbols
  ERR : 0xfffe0000100f1000: do_undefinstr not on kallsyms
  ERR : 0xfffe0000100f1320: do_sysinstr not on kallsyms
  ERR : 0xfffe0000100f13b0: do_debug_exception not on kallsyms
  ERR : 0xfffe0000100f1498: do_mem_abort not on kallsyms
  ERR : 0xfffe0000100f1580: do_sp_pc_abort not on kallsyms
  ...

After applying this patch, perf test 1 now succeeds:

  $ sudo ./newperf test -v 1 |& head
   1: vmlinux symtab matches kallsyms                       :
  test child forked, pid 33378
  Looking at the vmlinux_path (8 entries long)
  Using /usr/lib/debug/boot/vmlinux for symbols
  WARN: 0xffff000008081000: diff name v: do_undefinstr k: __exception_text_start
  WARN: 0xffff0000080819e8: diff name v: __irqentry_text_end k: __softirqentry_text_start
  WARN: 0xffff000008081d08: diff name v: __entry_text_start k: __softirqentry_text_end
  WARN: 0xffff00000809db5c: diff name v: flush_icache_range k: __flush_cache_user_range
  WARN: 0xffff000008101908: diff name v: sys_ni_syscall k: sys_vm86old
  ...

Signed-off-by: Kim Phillips <kim.phillips@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20171214175242.e30450f17f93ad675d968fa3@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Kim Phillips 2017-12-14 17:52:42 -06:00 committed by Arnaldo Carvalho de Melo
parent ca8000684e
commit f1031c8d33
2 changed files with 23 additions and 0 deletions
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1
tools/perf/arch/arm64/util/Build
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@ -1,4 +1,5 @@
libperf-y += header.o
libperf-y += sym-handling.o
libperf-$(CONFIG_DWARF) += dwarf-regs.o
libperf-$(CONFIG_LOCAL_LIBUNWIND) += unwind-libunwind.o

22
tools/perf/arch/arm64/util/sym-handling.c Normal file
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@ -0,0 +1,22 @@
/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2, as
* published by the Free Software Foundation.
*
* Copyright (C) 2015 Naveen N. Rao, IBM Corporation
*/
#include "debug.h"
#include "symbol.h"
#include "map.h"
#include "probe-event.h"
#include "probe-file.h"
#ifdef HAVE_LIBELF_SUPPORT
bool elf__needs_adjust_symbols(GElf_Ehdr ehdr)
{
return ehdr.e_type == ET_EXEC ||
ehdr.e_type == ET_REL ||
ehdr.e_type == ET_DYN;
}
#endif