Fixing Will's email (make sure to run get_maintainer.pl against the latest kernel tree so that .mailmap can do its thing). Original thread: https://lore.kernel.org/r/20210416232341.2421342-1-jiancai@xxxxxxxxxx/ On Wed, May 05, 2021 at 02:07:14PM -0700, Nathan Chancellor wrote: > Hi Jian, > > On Fri, Apr 16, 2021 at 04:23:41PM -0700, Jian Cai wrote: > > LLVM's integrated assembler does not support using commas separating > > the name and arguments in .macro. However, only spaces are used in the > > manual page. This replaces commas between macro names and the subsequent > > arguments with space in calls to clock_gettime_return to make it > > compatible with IAS. > > > > Link: > > https://sourceware.org/binutils/docs/as/Macro.html#Macro > > https://github.com/ClangBuiltLinux/linux/issues/1349 > > > > Signed-off-by: Jian Cai <jiancai@xxxxxxxxxx> > > The actual patch itself looks fine to me but there should be some more > explanation in the commit message that this patch is for 4.19 only and > why it is not applicable upstream. Additionally, I would recommend using > the '--subject-prefix=' flag to 'git format-patch' to clarify that as > well, something like '--subject-prefix="PATCH 4.19 ONLY"'? > > My explanation would be something like (take bits and pieces as you feel > necessary): > > ======================================================================== > > [PATCH 4.19 ONLY] arm64: vdso: remove commas between macro name and > arguments > > LLVM's integrated assembler does not support using a comma to separate > a macro name and its arguments when there is only one argument with a > default value: > > arch/arm64/kernel/vdso/gettimeofday.S:230:24: error: too many positional > arguments > clock_gettime_return, shift=1 > ^ > arch/arm64/kernel/vdso/gettimeofday.S:253:24: error: too many positional > arguments > clock_gettime_return, shift=1 > ^ > arch/arm64/kernel/vdso/gettimeofday.S:274:24: error: too many positional > arguments > clock_gettime_return, shift=1 > ^ > > This error is not in mainline because commit 28b1a824a4f4 ("arm64: vdso: > Substitute gettimeofday() with C implementation") rewrote this assembler > file in C as part of a 25 patch series that is unsuitable for stable. > Just remove the comma in the clock_gettime_return invocations in 4.19 so > that GNU as and LLVM's integrated assembler work the same. > > ======================================================================== > > I worded the first sentence the way that I did because correct me if I > am wrong but it seems that the integrated assembler has no issues with > the use of commas separating the arguments in a .macro definition as > that is done everywhere in arch/arm64, just not when there is a single > parameter with a default value because essentially what it is evaluating > it to is "clock_gettime_return ,shift=1", which according to the GAS > manual [1] means that "shift" is actually being set to 0 then there is an > other parameter, when it expects only one. > > [1]: After the definition is complete, you can call the macro either as > ‘reserve_str a,b’ (with ‘\p1’ evaluating to a and ‘\p2’ evaluating to > b), or as ‘reserve_str ,b’ (with ‘\p1’ evaluating as the default, in > this case ‘0’, and ‘\p2’ evaluating to b). > > Lastly, Will or Catalin should ack this as an explicitly out of mainline > patch so that Greg or Sasha can take it. I would put them on the "To:" > line in addition to Greg and Sasha. > > Hopefully this is helpful! > > Cheers, > Nathan > > > --- > > > > Changes v1 -> v2: > > Keep the comma in the macro definition to be consistent with other > > definitions. > > > > Changes v2 -> v3: > > Edit tags. > > > > arch/arm64/kernel/vdso/gettimeofday.S | 6 +++--- > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > diff --git a/arch/arm64/kernel/vdso/gettimeofday.S b/arch/arm64/kernel/vdso/gettimeofday.S > > index 856fee6d3512..b6faf8b5d1fe 100644 > > --- a/arch/arm64/kernel/vdso/gettimeofday.S > > +++ b/arch/arm64/kernel/vdso/gettimeofday.S > > @@ -227,7 +227,7 @@ realtime: > > seqcnt_check fail=realtime > > get_ts_realtime res_sec=x10, res_nsec=x11, \ > > clock_nsec=x15, xtime_sec=x13, xtime_nsec=x14, nsec_to_sec=x9 > > - clock_gettime_return, shift=1 > > + clock_gettime_return shift=1 > > > > ALIGN > > monotonic: > > @@ -250,7 +250,7 @@ monotonic: > > clock_nsec=x15, xtime_sec=x13, xtime_nsec=x14, nsec_to_sec=x9 > > > > add_ts sec=x10, nsec=x11, ts_sec=x3, ts_nsec=x4, nsec_to_sec=x9 > > - clock_gettime_return, shift=1 > > + clock_gettime_return shift=1 > > > > ALIGN > > monotonic_raw: > > @@ -271,7 +271,7 @@ monotonic_raw: > > clock_nsec=x15, nsec_to_sec=x9 > > > > add_ts sec=x10, nsec=x11, ts_sec=x13, ts_nsec=x14, nsec_to_sec=x9 > > - clock_gettime_return, shift=1 > > + clock_gettime_return shift=1 > > > > ALIGN > > realtime_coarse: > > -- > > 2.31.1.368.gbe11c130af-goog > > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
