On Sat, 2021-01-23 at 20:44 +0530, Aditya Srivastava wrote: > objtool requires that all code must be contained in an ELF symbol. > Symbol names that have a '.L' prefix do not emit symbol table entries, as > they have special meaning for the assembler. > > '.L' prefixed symbols can be used within a code region, but should be > avoided for denoting a range of code via 'SYM_*_START/END' annotations. > > Add a new check to emit a warning on finding the usage of '.L' symbols > for '.S' files in arch/x86/entry/* and arch/x86/lib/*, if it denotes > range of code via SYM_*_START/END annotation pair. > > Suggested-by: Mark Brown <[email protected]> > Link: > https://groups.google.com/g/clang-built-linux/c/-drkmLgu-cU/m/4staOlf-CgAJ
Please do not use groups.google.com links, or if you must, please use links that are readable. For instance, this is a better link as it shows the context without struggling with the poor interface: https://groups.google.com/g/clang-built-linux/c/E-naBMt_1SM > Signed-off-by: Aditya Srivastava <[email protected]> > --- > * Applies perfectly on next-20210122 > > Changes in v2: > - Reduce the check to only SYM_*_START/END lines > - Reduce the check for only .S files in arch/x86/entry/* and arch/x86/lib/* > as suggested by Josh and Nick I think that's unnecessary. > diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl [] > @@ -3590,6 +3590,13 @@ sub process { > } > } > > > +# check for .L prefix local symbols in .S files > + if ($realfile =~ m@^arch/x86/(?:entry|lib)/.*\.S$@ && Using /.S$/ should be enough > + $line =~ > /^\+\s*SYM_[A-Z]+_(?:START|END)(?:_[A-Z_]+)?\s*\(\s*\.L/) { This might need to be + $line =~ /^\+\s*(?:[A-Z]+_)?SYM_[A-Z]+_(?:START|END)(?:_[A-Z_]+)?\s*\(\s*\.L/) { > + WARN("AVOID_L_PREFIX", > + "Avoid using '.L' prefixed local symbol names for > denoting a range of code via 'SYM_*_START/END' annotations; see > Documentation/asm-annotations.rst\n" . $herecurr); > + } > +
