On 21/1/21 12:13 am, Joe Perches wrote: > On Wed, 2021-01-20 at 18:23 +0530, Aditya wrote: >> On 20/1/21 2:51 pm, Joe Perches wrote: >>> On Wed, 2021-01-20 at 12:55 +0530, Aditya Srivastava wrote: >>>> Local symbols prefixed with '.L' 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 >>>> in '.S' files, if it lies within SYM_*_START/END annotation pair. >>> >>> I believe this needs a test for $file as it won't work well on >>> patches as the SYM_*_START/END may not be in the patch context. >>> >> Okay. >> >>> Also, is this supposed to work for local labels like '.L<foo>:'? >>> I don't think a warning should be generated for those. >>> >> Yes, currently it will generate warning for all symbols which start >> with .L and have non- white character symbol following it, if it is >> lying within SYM_*_START/END annotation pair. >> >> Should I reduce the check to \.L_\S+ instead? (please note "_" >> following ".L") > > Use grep first. That would still match several existing labels. > >> Pardon me, I'm not good with assembly :/ > > Spending time reading docs can help with that. > > Mark? Can you please comment about the below? > > I believe the test should be: > > if ($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)" 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. 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? Thanks Aditya > WARN(...); > } > > so that only this code currently matches: > > $ git grep -P '^\s*SYM_[A-Z]+_(?:START|END)(?:_[A-Z_]+)?\s*\(\s*\.L' -- '*.S' > arch/x86/boot/compressed/head_32.S:SYM_FUNC_START_LOCAL_NOALIGN(.Lrelocated) > arch/x86/boot/compressed/head_32.S:SYM_FUNC_END(.Lrelocated) > arch/x86/boot/compressed/head_64.S:SYM_FUNC_START_LOCAL_NOALIGN(.Lrelocated) > arch/x86/boot/compressed/head_64.S:SYM_FUNC_END(.Lrelocated) > arch/x86/boot/compressed/head_64.S:SYM_FUNC_START_LOCAL_NOALIGN(.Lpaging_enabled) > arch/x86/boot/compressed/head_64.S:SYM_FUNC_END(.Lpaging_enabled) > arch/x86/boot/compressed/head_64.S:SYM_FUNC_START_LOCAL_NOALIGN(.Lno_longmode) > arch/x86/boot/compressed/head_64.S:SYM_FUNC_END(.Lno_longmode) > arch/x86/boot/pmjump.S:SYM_FUNC_START_LOCAL_NOALIGN(.Lin_pm32) > arch/x86/boot/pmjump.S:SYM_FUNC_END(.Lin_pm32) > arch/x86/entry/entry_64.S:SYM_CODE_START_LOCAL_NOALIGN(.Lbad_gs) > arch/x86/entry/entry_64.S:SYM_CODE_END(.Lbad_gs) > arch/x86/lib/copy_user_64.S:SYM_CODE_START_LOCAL(.Lcopy_user_handle_tail) > arch/x86/lib/copy_user_64.S:SYM_CODE_END(.Lcopy_user_handle_tail) > arch/x86/lib/getuser.S:SYM_CODE_START_LOCAL(.Lbad_get_user_clac) > arch/x86/lib/getuser.S:SYM_CODE_END(.Lbad_get_user_clac) > arch/x86/lib/getuser.S:SYM_CODE_START_LOCAL(.Lbad_get_user_8_clac) > arch/x86/lib/getuser.S:SYM_CODE_END(.Lbad_get_user_8_clac) > arch/x86/lib/putuser.S:SYM_CODE_START_LOCAL(.Lbad_put_user_clac) > arch/x86/lib/putuser.S:SYM_CODE_END(.Lbad_put_user_clac) > arch/x86/realmode/rm/wakeup_asm.S:SYM_DATA_START_LOCAL(.Lwakeup_idt) > arch/x86/realmode/rm/wakeup_asm.S:SYM_DATA_END(.Lwakeup_idt) > >