From: Joe Perches <joe@perches.com> To: Aditya Srivastava <yashsri421@gmail.com>, linux-kernel@vger.kernel.org Cc: lukas.bulwahn@gmail.com, dwaipayanray1@gmail.com, broonie@kernel.org, ndesaulniers@google.com, jpoimboe@redhat.com, linux-kernel-mentees@lists.linuxfoundation.org, clang-built-linux@googlegroups.com Subject: Re: [PATCH v2] checkpatch: add warning for avoiding .L prefix symbols in assembly files Date: Sat, 23 Jan 2021 09:21:02 -0800 [thread overview] Message-ID: <d5eacb78bd354d26725c34d887a75bf1e8f27a04.camel@perches.com> (raw) In-Reply-To: <20210123151405.26267-1-yashsri421@gmail.com> 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 <broonie@kernel.org> > 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 <yashsri421@gmail.com> > --- > * 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); > + } > +
WARNING: multiple messages have this Message-ID (diff)
From: Joe Perches <joe@perches.com> To: Aditya Srivastava <yashsri421@gmail.com>, linux-kernel@vger.kernel.org Cc: dwaipayanray1@gmail.com, ndesaulniers@google.com, clang-built-linux@googlegroups.com, broonie@kernel.org, jpoimboe@redhat.com, linux-kernel-mentees@lists.linuxfoundation.org Subject: Re: [Linux-kernel-mentees] [PATCH v2] checkpatch: add warning for avoiding .L prefix symbols in assembly files Date: Sat, 23 Jan 2021 09:21:02 -0800 [thread overview] Message-ID: <d5eacb78bd354d26725c34d887a75bf1e8f27a04.camel@perches.com> (raw) In-Reply-To: <20210123151405.26267-1-yashsri421@gmail.com> 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 <broonie@kernel.org> > 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 <yashsri421@gmail.com> > --- > * 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); > + } > + _______________________________________________ Linux-kernel-mentees mailing list Linux-kernel-mentees@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees
next prev parent reply other threads:[~2021-01-23 17:22 UTC|newest] Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-01-20 7:25 [PATCH] checkpatch: add warning for avoiding .L prefix symbols in assembly files Aditya Srivastava 2021-01-20 7:25 ` [Linux-kernel-mentees] " Aditya Srivastava 2021-01-20 9:21 ` Joe Perches 2021-01-20 9:21 ` [Linux-kernel-mentees] " Joe Perches 2021-01-20 12:53 ` Aditya 2021-01-20 12:53 ` [Linux-kernel-mentees] " Aditya 2021-01-20 18:43 ` Joe Perches 2021-01-20 18:43 ` [Linux-kernel-mentees] " Joe Perches 2021-01-20 18:57 ` Nick Desaulniers 2021-01-20 18:57 ` [Linux-kernel-mentees] " Nick Desaulniers via Linux-kernel-mentees 2021-01-20 22:59 ` Josh Poimboeuf 2021-01-20 22:59 ` [Linux-kernel-mentees] " Josh Poimboeuf 2021-01-22 13:18 ` Aditya 2021-01-22 13:18 ` [Linux-kernel-mentees] " Aditya 2021-01-22 19:10 ` Joe Perches 2021-01-22 19:10 ` [Linux-kernel-mentees] " Joe Perches 2021-01-22 20:13 ` Aditya 2021-01-22 20:13 ` [Linux-kernel-mentees] " Aditya 2021-01-22 20:36 ` Fāng-ruì Sòng 2021-01-22 20:36 ` [Linux-kernel-mentees] " Fāng-ruì Sòng via Linux-kernel-mentees 2021-01-23 15:14 ` [PATCH v2] " Aditya Srivastava 2021-01-23 15:14 ` [Linux-kernel-mentees] " Aditya Srivastava 2021-01-23 17:21 ` Joe Perches [this message] 2021-01-23 17:21 ` Joe Perches 2021-01-23 18:23 ` Aditya 2021-01-23 18:23 ` [Linux-kernel-mentees] " Aditya 2021-01-23 19:04 ` [PATCH v3] " Aditya Srivastava 2021-01-23 19:04 ` [Linux-kernel-mentees] " Aditya Srivastava 2021-01-23 21:01 ` Joe Perches 2021-01-23 21:01 ` [Linux-kernel-mentees] " Joe Perches 2021-01-25 18:15 ` Nick Desaulniers 2021-01-25 18:15 ` [Linux-kernel-mentees] " Nick Desaulniers via Linux-kernel-mentees
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