Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1623417 > unrolled thread
| Started by | Matthias Kaehlcke <mka@chromium.org> |
|---|---|
| First post | 2017-04-14 01:20 +0200 |
| Last post | 2017-04-14 07:40 +0200 |
| Articles | 4 — 3 participants |
Back to article view | Back to linux.kernel
This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by
below is the oldest one visible, not the original post.
Re: [PATCH 3/7] x86, LLVM: suppress clang warnings about unaligned accesses Matthias Kaehlcke <mka@chromium.org> - 2017-04-14 01:20 +0200
Re: [PATCH 3/7] x86, LLVM: suppress clang warnings about unaligned accesses "H. Peter Anvin" <hpa@zytor.com> - 2017-04-14 02:00 +0200
Re: [PATCH 3/7] x86, LLVM: suppress clang warnings about unaligned accesses Matthias Kaehlcke <mka@chromium.org> - 2017-04-14 02:30 +0200
Re: [PATCH 3/7] x86, LLVM: suppress clang warnings about unaligned accesses hpa@zytor.com - 2017-04-14 07:40 +0200
| From | Matthias Kaehlcke <mka@chromium.org> |
|---|---|
| Date | 2017-04-14 01:20 +0200 |
| Subject | Re: [PATCH 3/7] x86, LLVM: suppress clang warnings about unaligned accesses |
| Message-ID | <tvWbU-1xv-7@gated-at.bofh.it> |
El Mon, Apr 03, 2017 at 04:01:58PM -0700 Matthias Kaehlcke ha dit: > El Fri, Mar 17, 2017 at 04:50:19PM -0700 hpa@zytor.com ha dit: > > > On March 16, 2017 5:15:16 PM PDT, Michael Davidson <md@google.com> wrote: > > >Suppress clang warnings about potential unaliged accesses > > >to members in packed structs. This gets rid of almost 10,000 > > >warnings about accesses to the ring 0 stack pointer in the TSS. > > > > > >Signed-off-by: Michael Davidson <md@google.com> > > >--- > > > arch/x86/Makefile | 5 +++++ > > > 1 file changed, 5 insertions(+) > > > > > >diff --git a/arch/x86/Makefile b/arch/x86/Makefile > > >index 894a8d18bf97..7f21703c475d 100644 > > >--- a/arch/x86/Makefile > > >+++ b/arch/x86/Makefile > > >@@ -128,6 +128,11 @@ endif > > > KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args) > > > endif > > > > > >+ifeq ($(cc-name),clang) > > >+# Suppress clang warnings about potential unaligned accesses. > > >+KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member) > > >+endif > > >+ > > > ifdef CONFIG_X86_X32 > > > x32_ld_ok := $(call try-run,\ > > > /bin/echo -e '1: .quad 1b' | \ > > > > Why conditional on clang? > > My understanding is that this warning is clang specific, it is not > listed on https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html Actually this warning affects other platforms besides x86 (e.g. arm64), I'll submit a patch that disables the warning on all platforms. Cheers Matthias
[toc] | [next] | [standalone]
| From | "H. Peter Anvin" <hpa@zytor.com> |
|---|---|
| Date | 2017-04-14 02:00 +0200 |
| Message-ID | <tvWOB-1Nu-3@gated-at.bofh.it> |
| In reply to | #1623417 |
On 04/13/17 16:14, Matthias Kaehlcke wrote: > El Mon, Apr 03, 2017 at 04:01:58PM -0700 Matthias Kaehlcke ha dit: > >> El Fri, Mar 17, 2017 at 04:50:19PM -0700 hpa@zytor.com ha dit: >> >>> On March 16, 2017 5:15:16 PM PDT, Michael Davidson <md@google.com> wrote: >>>> Suppress clang warnings about potential unaliged accesses >>>> to members in packed structs. This gets rid of almost 10,000 >>>> warnings about accesses to the ring 0 stack pointer in the TSS. >>>> >>>> Signed-off-by: Michael Davidson <md@google.com> >>>> --- >>>> arch/x86/Makefile | 5 +++++ >>>> 1 file changed, 5 insertions(+) >>>> >>>> diff --git a/arch/x86/Makefile b/arch/x86/Makefile >>>> index 894a8d18bf97..7f21703c475d 100644 >>>> --- a/arch/x86/Makefile >>>> +++ b/arch/x86/Makefile >>>> @@ -128,6 +128,11 @@ endif >>>> KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args) >>>> endif >>>> >>>> +ifeq ($(cc-name),clang) >>>> +# Suppress clang warnings about potential unaligned accesses. >>>> +KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member) >>>> +endif >>>> + >>>> ifdef CONFIG_X86_X32 >>>> x32_ld_ok := $(call try-run,\ >>>> /bin/echo -e '1: .quad 1b' | \ >>> >>> Why conditional on clang? >> >> My understanding is that this warning is clang specific, it is not >> listed on https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html > > Actually this warning affects other platforms besides x86 > (e.g. arm64), I'll submit a patch that disables the warning on all > platforms. > Drop the ifeq ($(cc-name),clang). You should assume that if you have to add one of those ifeq's then you are doing something fundamentally wrong. -hpa
[toc] | [prev] | [next] | [standalone]
| From | Matthias Kaehlcke <mka@chromium.org> |
|---|---|
| Date | 2017-04-14 02:30 +0200 |
| Message-ID | <tvXhE-2eF-5@gated-at.bofh.it> |
| In reply to | #1623440 |
El Thu, Apr 13, 2017 at 04:55:00PM -0700 H. Peter Anvin ha dit: > On 04/13/17 16:14, Matthias Kaehlcke wrote: > > El Mon, Apr 03, 2017 at 04:01:58PM -0700 Matthias Kaehlcke ha dit: > > > >> El Fri, Mar 17, 2017 at 04:50:19PM -0700 hpa@zytor.com ha dit: > >> > >>> On March 16, 2017 5:15:16 PM PDT, Michael Davidson <md@google.com> wrote: > >>>> Suppress clang warnings about potential unaliged accesses > >>>> to members in packed structs. This gets rid of almost 10,000 > >>>> warnings about accesses to the ring 0 stack pointer in the TSS. > >>>> > >>>> Signed-off-by: Michael Davidson <md@google.com> > >>>> --- > >>>> arch/x86/Makefile | 5 +++++ > >>>> 1 file changed, 5 insertions(+) > >>>> > >>>> diff --git a/arch/x86/Makefile b/arch/x86/Makefile > >>>> index 894a8d18bf97..7f21703c475d 100644 > >>>> --- a/arch/x86/Makefile > >>>> +++ b/arch/x86/Makefile > >>>> @@ -128,6 +128,11 @@ endif > >>>> KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args) > >>>> endif > >>>> > >>>> +ifeq ($(cc-name),clang) > >>>> +# Suppress clang warnings about potential unaligned accesses. > >>>> +KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member) > >>>> +endif > >>>> + > >>>> ifdef CONFIG_X86_X32 > >>>> x32_ld_ok := $(call try-run,\ > >>>> /bin/echo -e '1: .quad 1b' | \ > >>> > >>> Why conditional on clang? > >> > >> My understanding is that this warning is clang specific, it is not > >> listed on https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html > > > > Actually this warning affects other platforms besides x86 > > (e.g. arm64), I'll submit a patch that disables the warning on all > > platforms. > > > > Drop the ifeq ($(cc-name),clang). > > You should assume that if you have to add one of those ifeq's then you > are doing something fundamentally wrong. Thanks, however in the case of the global Makefile it seems we should put it inside the already existing clang section: http://lxr.free-electrons.com/source/Makefile#L692 Cheers Matthias
[toc] | [prev] | [next] | [standalone]
| From | hpa@zytor.com |
|---|---|
| Date | 2017-04-14 07:40 +0200 |
| Subject | Re: [PATCH 3/7] x86, LLVM: suppress clang warnings about unaligned accesses |
| Message-ID | <tw27E-5Bu-3@gated-at.bofh.it> |
| In reply to | #1623444 |
On April 13, 2017 5:23:35 PM PDT, Matthias Kaehlcke <mka@chromium.org> wrote: >El Thu, Apr 13, 2017 at 04:55:00PM -0700 H. Peter Anvin ha dit: > >> On 04/13/17 16:14, Matthias Kaehlcke wrote: >> > El Mon, Apr 03, 2017 at 04:01:58PM -0700 Matthias Kaehlcke ha dit: >> > >> >> El Fri, Mar 17, 2017 at 04:50:19PM -0700 hpa@zytor.com ha dit: >> >> >> >>> On March 16, 2017 5:15:16 PM PDT, Michael Davidson ><md@google.com> wrote: >> >>>> Suppress clang warnings about potential unaliged accesses >> >>>> to members in packed structs. This gets rid of almost 10,000 >> >>>> warnings about accesses to the ring 0 stack pointer in the TSS. >> >>>> >> >>>> Signed-off-by: Michael Davidson <md@google.com> >> >>>> --- >> >>>> arch/x86/Makefile | 5 +++++ >> >>>> 1 file changed, 5 insertions(+) >> >>>> >> >>>> diff --git a/arch/x86/Makefile b/arch/x86/Makefile >> >>>> index 894a8d18bf97..7f21703c475d 100644 >> >>>> --- a/arch/x86/Makefile >> >>>> +++ b/arch/x86/Makefile >> >>>> @@ -128,6 +128,11 @@ endif >> >>>> KBUILD_CFLAGS += $(call >cc-option,-maccumulate-outgoing-args) >> >>>> endif >> >>>> >> >>>> +ifeq ($(cc-name),clang) >> >>>> +# Suppress clang warnings about potential unaligned accesses. >> >>>> +KBUILD_CFLAGS += $(call cc-disable-warning, >address-of-packed-member) >> >>>> +endif >> >>>> + >> >>>> ifdef CONFIG_X86_X32 >> >>>> x32_ld_ok := $(call try-run,\ >> >>>> /bin/echo -e '1: .quad 1b' | \ >> >>> >> >>> Why conditional on clang? >> >> >> >> My understanding is that this warning is clang specific, it is not >> >> listed on https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html >> > >> > Actually this warning affects other platforms besides x86 >> > (e.g. arm64), I'll submit a patch that disables the warning on all >> > platforms. >> > >> >> Drop the ifeq ($(cc-name),clang). >> >> You should assume that if you have to add one of those ifeq's then >you >> are doing something fundamentally wrong. > >Thanks, however in the case of the global Makefile it seems we should >put it inside the already existing clang section: > >http://lxr.free-electrons.com/source/Makefile#L692 > >Cheers > >Matthias We shouldn't, unless it will actively break non-clang builds... -- Sent from my Android device with K-9 Mail. Please excuse my brevity.
[toc] | [prev] | [standalone]
Back to top | Article view | linux.kernel
csiph-web