From 2574108dd2d8528e6b28af78a145658c71da7630 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Thu, 24 Oct 2019 18:12:54 +0900 Subject: perf probe: Fix to show function entry line as probe-able commit 91e2f539eeda26ab00bd03fae8dc434c128c85ed upstream. Fix die_walk_lines() to list the function entry line correctly. Since the dwarf_entrypc() does not return the entry pc if the DIE has only range attribute, __die_walk_funclines() fails to list the declaration line (entry line) in that case. To solve this issue, this introduces die_entrypc() which correctly returns the entry PC (the first address range) even if the DIE has only range attribute. With this fix die_walk_lines() shows the function entry line is able to probe correctly. Fixes: 4cc9cec636e7 ("perf probe: Introduce lines walker interface") Signed-off-by: Masami Hiramatsu Cc: Jiri Olsa Cc: Namhyung Kim Link: http://lore.kernel.org/lkml/157190837419.1859.4619125803596816752.stgit@devnote2 Signed-off-by: Arnaldo Carvalho de Melo Cc: Thomas Backlund Signed-off-by: Greg Kroah-Hartman --- tools/perf/util/dwarf-aux.c | 24 +++++++++++++++++++++++- tools/perf/util/dwarf-aux.h | 3 +++ 2 files changed, 26 insertions(+), 1 deletion(-) (limited to 'tools') diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c index 388c9dcba976..fd460aca36e5 100644 --- a/tools/perf/util/dwarf-aux.c +++ b/tools/perf/util/dwarf-aux.c @@ -293,6 +293,28 @@ bool die_is_func_def(Dwarf_Die *dw_die) dwarf_attr(dw_die, DW_AT_declaration, &attr) == NULL); } +/** + * die_entrypc - Returns entry PC (the lowest address) of a DIE + * @dw_die: a DIE + * @addr: where to store entry PC + * + * Since dwarf_entrypc() does not return entry PC if the DIE has only address + * range, we have to use this to retrieve the lowest address from the address + * range attribute. + */ +int die_entrypc(Dwarf_Die *dw_die, Dwarf_Addr *addr) +{ + Dwarf_Addr base, end; + + if (!addr) + return -EINVAL; + + if (dwarf_entrypc(dw_die, addr) == 0) + return 0; + + return dwarf_ranges(dw_die, 0, &base, addr, &end) < 0 ? -ENOENT : 0; +} + /** * die_is_func_instance - Ensure that this DIE is an instance of a subprogram * @dw_die: a DIE @@ -706,7 +728,7 @@ static int __die_walk_funclines(Dwarf_Die *sp_die, bool recursive, /* Handle function declaration line */ fname = dwarf_decl_file(sp_die); if (fname && dwarf_decl_line(sp_die, &lineno) == 0 && - dwarf_entrypc(sp_die, &addr) == 0) { + die_entrypc(sp_die, &addr) == 0) { lw.retval = callback(fname, lineno, addr, data); if (lw.retval != 0) goto done; diff --git a/tools/perf/util/dwarf-aux.h b/tools/perf/util/dwarf-aux.h index c42ec366f2a7..598629333eec 100644 --- a/tools/perf/util/dwarf-aux.h +++ b/tools/perf/util/dwarf-aux.h @@ -38,6 +38,9 @@ extern int cu_find_lineinfo(Dwarf_Die *cudie, unsigned long addr, extern int cu_walk_functions_at(Dwarf_Die *cu_die, Dwarf_Addr addr, int (*callback)(Dwarf_Die *, void *), void *data); +/* Get the lowest PC in DIE (including range list) */ +int die_entrypc(Dwarf_Die *dw_die, Dwarf_Addr *addr); + /* Ensure that this DIE is a subprogram and definition (not declaration) */ extern bool die_is_func_def(Dwarf_Die *dw_die); -- cgit v1.2.3