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

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@redhat.com
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
[Manoj: Resolve conflict on 4.4.y/4.9.y because of missing 42c269c88dc1]
Signed-off-by: Manoj Gupta <manojgupta@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c
index 7250fb38350ce7f66a256f557d598fe84edfd0eb..8cba4c44da4c23eb7ebb9089f7bb05fb8ba6f261 100644 (file)
--- a/scripts/recordmcount.c
+++ b/scripts/recordmcount.c
@@ -362,7 +362,7 @@ 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(".ref.text",      txtname) == 0 ||
                strcmp(".sched.text",    txtname) == 0 ||
                strcmp(".spinlock.text", txtname) == 0 ||

diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl
index ccd6614ea21828b5af4bf3eba1d612b72deb112e..5ca4ec2970197e74541fd535673960bc02101006 100755 (executable)
--- a/scripts/recordmcount.pl
+++ b/scripts/recordmcount.pl
@@ -138,6 +138,11 @@ 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);
@@ -503,6 +508,14 @@ 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();