On Fri, Jan 22, 2021 at 12:13 PM Aditya [off-list ref] wrote:

On 23/1/21 12:40 am, Joe Perches wrote:

quoted

On Fri, 2021-01-22 at 18:48 +0530, Aditya wrote:

quoted

On 21/1/21 12:13 am, Joe Perches wrote:

quoted

I believe the test should be:

    if ($realfile =~ /\.S$/ &&
        $line =~ /^\+\s*SYM_[A-Z]+_(?:START|END)(?:_[A-Z_]+)?\s*\(\s*\.L/) {

Joe, with this regex, we won't be able to match
"jmp  .L_restore
SYM_FUNC_END(\name)"

I think that's not an issue.

quoted

which was replaced in this patch in the discussion:
https://groups.google.com/g/clang-built-linux/c/-drkmLgu-cU/m/phKe-Tb6CgAJ

Here, "jmp  .L_restore" was also replaced to fix the error.

Notice that this line was also replaced in the same patch:

 #ifdef CONFIG_PREEMPTION
-SYM_CODE_START_LOCAL_NOALIGN(.L_restore)
+SYM_CODE_START_LOCAL_NOALIGN(__thunk_restore)

quoted

However, if this
regex(/^\+\s*SYM_[A-Z]+_(?:START|END)(?:_[A-Z_]+)?\s*\(\s*\.L/) is
correct, maybe we don't need to check for $file as we are now checking
for just one line.

What do you think?

The test I wrote was complete, did not use $file and emits a
warning on the use of CODE_SYM_START_LOCAL_NOALIGN(.L_restore)

I think it's sufficient.

Okay, Thanks.. I will send the modified patch :)

Thanks
Aditya

I am slightly concerned with the direction here.   jmp .Lsym is fine
and is probably preferable in cases where you absolutely want to emit
a local symbol.
(there is a related -z unique-symbol GNU ld+FGKASLR thing I shall
analyze in my spare time)

If the problem is just that STT_SECTION symbols are missing, can
objtool do something to conceptually synthesize them?
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