From f1031c8d33a8c40d4cac26e58c37d9fba0e31a8a Mon Sep 17 00:00:00 2001 From: Kim Phillips Date: Thu, 14 Dec 2017 17:52:42 -0600 Subject: [PATCH] perf probe arm64: Fix symbol fixup issues due to ELF type 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 d2332098331f ("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 Cc: Alexander Shishkin Cc: Ganapatrao Kulkarni Cc: Jiri Olsa Cc: Namhyung Kim Cc: Naveen N. Rao Cc: Peter Zijlstra Cc: Will Deacon Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/20171214175242.e30450f17f93ad675d968fa3@arm.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/arch/arm64/util/Build | 1 + tools/perf/arch/arm64/util/sym-handling.c | 22 ++++++++++++++++++++++ 2 files changed, 23 insertions(+) create mode 100644 tools/perf/arch/arm64/util/sym-handling.c diff --git a/tools/perf/arch/arm64/util/Build b/tools/perf/arch/arm64/util/Build index b1ab72d2a42e..e04f6cdd6f32 100644 --- a/tools/perf/arch/arm64/util/Build +++ b/tools/perf/arch/arm64/util/Build @@ -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 diff --git a/tools/perf/arch/arm64/util/sym-handling.c b/tools/perf/arch/arm64/util/sym-handling.c new file mode 100644 index 000000000000..0051b1ee8450 --- /dev/null +++ b/tools/perf/arch/arm64/util/sym-handling.c @@ -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