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scripts/recordmcount.{c,pl}: support -ffunction-sections .text.* section names

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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@redhat.com

Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Joe Lawrence 2018-11-20 15:19:18 -05:00 committed by Steven Rostedt (VMware)
parent ca16b0fbb0
commit 9c8e2f6d3d
2 changed files with 14 additions and 1 deletions
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2
scripts/recordmcount.c
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@ -397,7 +397,7 @@ 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 ||

13
scripts/recordmcount.pl
View File

@ -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);
@ -519,6 +524,14 @@ 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();