On Fri, Mar 12, 2021 at 12:39 PM Manoj Gupta manojgupta@google.com wrote:
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
[nc: Resolve conflict because of missing 42c269c88dc146982a54a8267f71abc99f12852a] Signed-off-by: Manoj Gupta manojgupta@google.com
scripts/recordmcount.c | 2 +- scripts/recordmcount.pl | 13 +++++++++++++ 2 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c index 7250fb38350c..8cba4c44da4c 100644 --- 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 ccd6614ea218..5ca4ec297019 100755 --- 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();-- 2.31.0.rc2.261.g7f71774620-goog
This patch should apply cleanly to 4.4.y and 4.9.y branches.
Thanks, Manoj