From: Nathan Chancellor <nathan@kernel.org> To: Jian Cai <jiancai@google.com>, gregkh@linuxfoundation.org, sashal@kernel.org, will@kernel.org, catalin.marinas@arm.com Cc: stable@vger.kernel.org, ndesaulniers@google.com, manojgupta@google.com, llozano@google.com, clang-built-linux@googlegroups.com, Will Deacon <will.deacon@arm.com>, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 4.19 ONLY v4] arm64: vdso: remove commas between macro name and arguments Date: Thu, 6 May 2021 10:43:33 -0700 [thread overview] Message-ID: <fd08dce2-71c0-3414-d661-d065480c04ff@kernel.org> (raw) In-Reply-To: <20210506012508.3822221-1-jiancai@google.com> On 5/5/2021 6:25 PM, Jian Cai wrote: > LLVM's integrated assembler appears to assume an argument with default > value is passed whenever it sees a comma right after the macro name. > It will be fine if the number of following arguments is one less than > the number of parameters specified in the macro definition. Otherwise, > it fails. For example, the following code works: > > $ cat foo.s > .macro foo arg1=2, arg2=4 > ldr r0, [r1, #\arg1] > ldr r0, [r1, #\arg2] > .endm > > foo, arg2=8 > > $ llvm-mc -triple=armv7a -filetype=obj foo.s -o ias.o > arm-linux-gnueabihf-objdump -dr ias.o > > ias.o: file format elf32-littlearm > > Disassembly of section .text: > > 00000000 <.text>: > 0: e5910001 ldr r0, [r1, #2] > 4: e5910003 ldr r0, [r1, #8] > > While the the following code would fail: > > $ cat foo.s > .macro foo arg1=2, arg2=4 > ldr r0, [r1, #\arg1] > ldr r0, [r1, #\arg2] > .endm > > foo, arg1=2, arg2=8 > > $ llvm-mc -triple=armv7a -filetype=obj foo.s -o ias.o > foo.s:6:14: error: too many positional arguments > foo, arg1=2, arg2=8 > > This causes build failures as follows: > > 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. > > Link: > https://github.com/ClangBuiltLinux/linux/issues/1349 > > Suggested-by: Nathan Chancellor <nathan@kernel.org> > Signed-off-by: Jian Cai <jiancai@google.com> Thanks for the updated example and explanation, this looks good to me now. Reviewed-by: Nathan Chancellor <nathan@kernel.org> > --- > Changes v1 -> v2: > Keep the comma in the macro definition to be consistent with other > definitions. > > Changes v2 -> v3: > Edit tags. > > Changes v3 -> v4: > Update the commit message based on Nathan's comments. > > 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: >
WARNING: multiple messages have this Message-ID (diff)
From: Nathan Chancellor <nathan@kernel.org> To: Jian Cai <jiancai@google.com>, gregkh@linuxfoundation.org, sashal@kernel.org, will@kernel.org, catalin.marinas@arm.com Cc: stable@vger.kernel.org, ndesaulniers@google.com, manojgupta@google.com, llozano@google.com, clang-built-linux@googlegroups.com, Will Deacon <will.deacon@arm.com>, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 4.19 ONLY v4] arm64: vdso: remove commas between macro name and arguments Date: Thu, 6 May 2021 10:43:33 -0700 [thread overview] Message-ID: <fd08dce2-71c0-3414-d661-d065480c04ff@kernel.org> (raw) In-Reply-To: <20210506012508.3822221-1-jiancai@google.com> On 5/5/2021 6:25 PM, Jian Cai wrote: > LLVM's integrated assembler appears to assume an argument with default > value is passed whenever it sees a comma right after the macro name. > It will be fine if the number of following arguments is one less than > the number of parameters specified in the macro definition. Otherwise, > it fails. For example, the following code works: > > $ cat foo.s > .macro foo arg1=2, arg2=4 > ldr r0, [r1, #\arg1] > ldr r0, [r1, #\arg2] > .endm > > foo, arg2=8 > > $ llvm-mc -triple=armv7a -filetype=obj foo.s -o ias.o > arm-linux-gnueabihf-objdump -dr ias.o > > ias.o: file format elf32-littlearm > > Disassembly of section .text: > > 00000000 <.text>: > 0: e5910001 ldr r0, [r1, #2] > 4: e5910003 ldr r0, [r1, #8] > > While the the following code would fail: > > $ cat foo.s > .macro foo arg1=2, arg2=4 > ldr r0, [r1, #\arg1] > ldr r0, [r1, #\arg2] > .endm > > foo, arg1=2, arg2=8 > > $ llvm-mc -triple=armv7a -filetype=obj foo.s -o ias.o > foo.s:6:14: error: too many positional arguments > foo, arg1=2, arg2=8 > > This causes build failures as follows: > > 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. > > Link: > https://github.com/ClangBuiltLinux/linux/issues/1349 > > Suggested-by: Nathan Chancellor <nathan@kernel.org> > Signed-off-by: Jian Cai <jiancai@google.com> Thanks for the updated example and explanation, this looks good to me now. Reviewed-by: Nathan Chancellor <nathan@kernel.org> > --- > Changes v1 -> v2: > Keep the comma in the macro definition to be consistent with other > definitions. > > Changes v2 -> v3: > Edit tags. > > Changes v3 -> v4: > Update the commit message based on Nathan's comments. > > 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: > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-05-06 17:43 UTC|newest] Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-05-06 1:25 [PATCH 4.19 ONLY v4] arm64: vdso: remove commas between macro name and arguments Jian Cai 2021-05-06 1:25 ` Jian Cai 2021-05-06 17:43 ` Nathan Chancellor [this message] 2021-05-06 17:43 ` Nathan Chancellor 2021-05-10 8:03 ` Greg KH 2021-05-10 8:03 ` Greg KH 2021-05-10 8:28 ` Patch "arm64: vdso: remove commas between macro name and arguments" has been added to the 4.19-stable tree gregkh
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