From: Greg Kroah-Hartman gregkh@linuxfoundation.org
From: Joe Lawrence joe.lawrence@redhat.com
commit 9c8e2f6d3d361439cc6744a094f1c15681b55269 upstream.
When building with -ffunction-sections, the compiler will place each function into its own ELF section, prefixed with ".text". For example, a simple test module with functions test_module_do_work() and test_module_wq_func():
% objdump --section-headers test_module.o | awk '/.text/{print $2}' .text .text.test_module_do_work .text.test_module_wq_func .init.text .exit.text
Adjust the recordmcount scripts to look for ".text" as a section name prefix. This will ensure that those functions will be included in the __mcount_loc relocations:
% objdump --reloc --section __mcount_loc test_module.o OFFSET TYPE VALUE 0000000000000000 R_X86_64_64 .text.test_module_do_work 0000000000000008 R_X86_64_64 .text.test_module_wq_func 0000000000000010 R_X86_64_64 .init.text
Link: http://lkml.kernel.org/r/1542745158-25392-2-git-send-email-joe.lawrence@redh...
Signed-off-by: Joe Lawrence joe.lawrence@redhat.com Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org Cc: Manoj Gupta manojgupta@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- scripts/recordmcount.c | 2 +- scripts/recordmcount.pl | 13 +++++++++++++ 2 files changed, 14 insertions(+), 1 deletion(-)
--- a/scripts/recordmcount.c +++ b/scripts/recordmcount.c @@ -401,7 +401,7 @@ static uint32_t (*w2)(uint16_t); static int is_mcounted_section_name(char const *const txtname) { - return strcmp(".text", txtname) == 0 || + return strncmp(".text", txtname, 5) == 0 || strcmp(".init.text", txtname) == 0 || strcmp(".ref.text", txtname) == 0 || strcmp(".sched.text", txtname) == 0 || --- a/scripts/recordmcount.pl +++ b/scripts/recordmcount.pl @@ -142,6 +142,11 @@ my %text_sections = ( ".text.unlikely" => 1, );
+# Acceptable section-prefixes to record. +my %text_section_prefixes = ( + ".text." => 1, +); + # Note: we are nice to C-programmers here, thus we skip the '||='-idiom. $objdump = 'objdump' if (!$objdump); $objcopy = 'objcopy' if (!$objcopy); @@ -523,6 +528,14 @@ while (<IN>) {
# Only record text sections that we know are safe $read_function = defined($text_sections{$1}); + if (!$read_function) { + foreach my $prefix (keys %text_section_prefixes) { + if (substr($1, 0, length $prefix) eq $prefix) { + $read_function = 1; + last; + } + } + } # print out any recorded offsets update_funcs();