All of lore.kernel.org
 help / color / mirror / Atom feed
From: Nathan Chancellor <nathan@kernel.org>
To: masahiroy@kernel.org
Cc: ndesaulniers@google.com, nicolas@fjasle.eu, trix@redhat.com,
	 linux-kbuild@vger.kernel.org, llvm@lists.linux.dev,
	 Nathan Chancellor <nathan@kernel.org>,
	mpe@ellerman.id.au,  npiggin@gmail.com,
	christophe.leroy@csgroup.eu,  linuxppc-dev@lists.ozlabs.org
Subject: [PATCH v2 08/14] powerpc/vdso: Remove an unsupported flag from vgettimeofday-32.o with clang
Date: Wed, 11 Jan 2023 20:05:05 -0700	[thread overview]
Message-ID: <20221228-drop-qunused-arguments-v2-8-9adbddd20d86@kernel.org> (raw)
In-Reply-To: <20221228-drop-qunused-arguments-v2-0-9adbddd20d86@kernel.org>

When clang's -Qunused-arguments is dropped from KBUILD_CPPFLAGS, it
warns:

  clang-16: error: argument unused during compilation: '-fno-stack-clash-protection' [-Werror,-Wunused-command-line-argument]

This warning happens because vgettimeofday-32.c gets its base CFLAGS
from the main kernel, which may contain flags that are only supported on
a 64-bit target but not a 32-bit one, which is the case here.
-fstack-clash-protection and its negation are only suppported by the
64-bit powerpc target but that flag is included in an invocation for a
32-bit powerpc target, so clang points out that while the flag is one
that it recognizes, it is not actually used by this compiler job.

To eliminate the warning, remove -fno-stack-clash-protection from
vgettimeofday-32.c's CFLAGS when using clang, as has been done for other
flags previously.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
---
Cc: mpe@ellerman.id.au
Cc: npiggin@gmail.com
Cc: christophe.leroy@csgroup.eu
Cc: linuxppc-dev@lists.ozlabs.org
---
 arch/powerpc/kernel/vdso/Makefile | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/powerpc/kernel/vdso/Makefile b/arch/powerpc/kernel/vdso/Makefile
index 4337b3aa9171..e78a57e0a6c0 100644
--- a/arch/powerpc/kernel/vdso/Makefile
+++ b/arch/powerpc/kernel/vdso/Makefile
@@ -16,6 +16,11 @@ ifneq ($(c-gettimeofday-y),)
   CFLAGS_vgettimeofday-32.o += -ffreestanding -fasynchronous-unwind-tables
   CFLAGS_REMOVE_vgettimeofday-32.o = $(CC_FLAGS_FTRACE)
   CFLAGS_REMOVE_vgettimeofday-32.o += -mcmodel=medium -mabi=elfv1 -mabi=elfv2 -mcall-aixdesc
+  # This flag is supported by clang for 64-bit but not 32-bit so it will cause
+  # an unused command line flag warning for this file.
+  ifdef CONFIG_CC_IS_CLANG
+  CFLAGS_REMOVE_vgettimeofday-32.o += -fno-stack-clash-protection
+  endif
   CFLAGS_vgettimeofday-64.o += -include $(c-gettimeofday-y)
   CFLAGS_vgettimeofday-64.o += $(DISABLE_LATENT_ENTROPY_PLUGIN)
   CFLAGS_vgettimeofday-64.o += $(call cc-option, -fno-stack-protector)

-- 
2.39.0


WARNING: multiple messages have this Message-ID (diff)
From: Nathan Chancellor <nathan@kernel.org>
To: masahiroy@kernel.org
Cc: nicolas@fjasle.eu, linux-kbuild@vger.kernel.org, trix@redhat.com,
	llvm@lists.linux.dev, ndesaulniers@google.com, npiggin@gmail.com,
	Nathan Chancellor <nathan@kernel.org>,
	linuxppc-dev@lists.ozlabs.org
Subject: [PATCH v2 08/14] powerpc/vdso: Remove an unsupported flag from vgettimeofday-32.o with clang
Date: Wed, 11 Jan 2023 20:05:05 -0700	[thread overview]
Message-ID: <20221228-drop-qunused-arguments-v2-8-9adbddd20d86@kernel.org> (raw)
In-Reply-To: <20221228-drop-qunused-arguments-v2-0-9adbddd20d86@kernel.org>

When clang's -Qunused-arguments is dropped from KBUILD_CPPFLAGS, it
warns:

  clang-16: error: argument unused during compilation: '-fno-stack-clash-protection' [-Werror,-Wunused-command-line-argument]

This warning happens because vgettimeofday-32.c gets its base CFLAGS
from the main kernel, which may contain flags that are only supported on
a 64-bit target but not a 32-bit one, which is the case here.
-fstack-clash-protection and its negation are only suppported by the
64-bit powerpc target but that flag is included in an invocation for a
32-bit powerpc target, so clang points out that while the flag is one
that it recognizes, it is not actually used by this compiler job.

To eliminate the warning, remove -fno-stack-clash-protection from
vgettimeofday-32.c's CFLAGS when using clang, as has been done for other
flags previously.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
---
Cc: mpe@ellerman.id.au
Cc: npiggin@gmail.com
Cc: christophe.leroy@csgroup.eu
Cc: linuxppc-dev@lists.ozlabs.org
---
 arch/powerpc/kernel/vdso/Makefile | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/powerpc/kernel/vdso/Makefile b/arch/powerpc/kernel/vdso/Makefile
index 4337b3aa9171..e78a57e0a6c0 100644
--- a/arch/powerpc/kernel/vdso/Makefile
+++ b/arch/powerpc/kernel/vdso/Makefile
@@ -16,6 +16,11 @@ ifneq ($(c-gettimeofday-y),)
   CFLAGS_vgettimeofday-32.o += -ffreestanding -fasynchronous-unwind-tables
   CFLAGS_REMOVE_vgettimeofday-32.o = $(CC_FLAGS_FTRACE)
   CFLAGS_REMOVE_vgettimeofday-32.o += -mcmodel=medium -mabi=elfv1 -mabi=elfv2 -mcall-aixdesc
+  # This flag is supported by clang for 64-bit but not 32-bit so it will cause
+  # an unused command line flag warning for this file.
+  ifdef CONFIG_CC_IS_CLANG
+  CFLAGS_REMOVE_vgettimeofday-32.o += -fno-stack-clash-protection
+  endif
   CFLAGS_vgettimeofday-64.o += -include $(c-gettimeofday-y)
   CFLAGS_vgettimeofday-64.o += $(DISABLE_LATENT_ENTROPY_PLUGIN)
   CFLAGS_vgettimeofday-64.o += $(call cc-option, -fno-stack-protector)

-- 
2.39.0


  parent reply	other threads:[~2023-01-12  3:05 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-12  3:04 [PATCH v2 00/14] Remove clang's -Qunused-arguments from KBUILD_CPPFLAGS Nathan Chancellor
2023-01-12  3:04 ` Nathan Chancellor
2023-01-12  3:04 ` Nathan Chancellor
2023-01-12  3:04 ` [PATCH v2 01/14] x86/boot/compressed: prefer cc-option for CFLAGS additions Nathan Chancellor
2023-01-12  3:04 ` [PATCH v2 02/14] MIPS: Always use -Wa,-msoft-float and eliminate GAS_HAS_SET_HARDFLOAT Nathan Chancellor
2023-01-12  3:05 ` [PATCH v2 03/14] MIPS: Prefer cc-option for additions to cflags Nathan Chancellor
2023-01-12  3:05 ` [PATCH v2 04/14] kbuild: Update assembler calls to use proper flags and language target Nathan Chancellor
2023-01-12  3:05 ` [PATCH v2 05/14] powerpc: Remove linker flag from KBUILD_AFLAGS Nathan Chancellor
2023-01-12  3:05   ` Nathan Chancellor
2023-01-25  4:11   ` Michael Ellerman
2023-01-25  4:11     ` Michael Ellerman
2023-01-26  1:29     ` Masahiro Yamada
2023-01-26  1:29       ` Masahiro Yamada
2023-01-26  2:07       ` Nathan Chancellor
2023-01-26  2:07         ` Nathan Chancellor
2023-01-26  4:22         ` Masahiro Yamada
2023-01-26  4:22           ` Masahiro Yamada
2023-01-26 10:05           ` Michael Ellerman
2023-01-26 10:05             ` Michael Ellerman
2023-01-12  3:05 ` [PATCH v2 06/14] powerpc/vdso: Remove unused '-s' flag from ASFLAGS Nathan Chancellor
2023-01-12  3:05   ` Nathan Chancellor
2023-01-25  4:12   ` Michael Ellerman
2023-01-25  4:12     ` Michael Ellerman
2023-01-12  3:05 ` [PATCH v2 07/14] powerpc/vdso: Improve linker flags Nathan Chancellor
2023-01-12  3:05   ` Nathan Chancellor
2023-01-12 18:02   ` Sedat Dilek
2023-01-12 18:02     ` Sedat Dilek
2023-01-12 18:21     ` Nathan Chancellor
2023-01-12 18:21       ` Nathan Chancellor
2023-01-12 18:47       ` Sedat Dilek
2023-01-12 18:47         ` Sedat Dilek
2023-01-22 17:27       ` Masahiro Yamada
2023-01-22 17:27         ` Masahiro Yamada
2023-01-22 18:01         ` Nathan Chancellor
2023-01-22 18:01           ` Nathan Chancellor
2023-01-23 15:07   ` Segher Boessenkool
2023-01-23 15:07     ` Segher Boessenkool
2023-01-24 16:14     ` Nathan Chancellor
2023-01-24 16:14       ` Nathan Chancellor
2023-01-24 16:30       ` Segher Boessenkool
2023-01-24 16:30         ` Segher Boessenkool
2023-01-12  3:05 ` Nathan Chancellor [this message]
2023-01-12  3:05   ` [PATCH v2 08/14] powerpc/vdso: Remove an unsupported flag from vgettimeofday-32.o with clang Nathan Chancellor
2023-01-12  3:05 ` [PATCH v2 09/14] s390/vdso: Drop unused '-s' flag from KBUILD_AFLAGS_64 Nathan Chancellor
2023-01-12  3:05 ` [PATCH v2 10/14] s390/vdso: Drop '-shared' from KBUILD_CFLAGS_64 Nathan Chancellor
2023-01-12  3:05 ` [PATCH v2 11/14] s390/purgatory: Remove unused '-MD' and unnecessary '-c' flags Nathan Chancellor
2023-01-12  3:05 ` [PATCH v2 12/14] drm/amd/display: Do not add '-mhard-float' to dml_ccflags for clang Nathan Chancellor
2023-01-12  3:05   ` Nathan Chancellor
2023-01-12  3:05 ` [PATCH v2 13/14] kbuild: Turn a couple more of clang's unused option warnings into errors Nathan Chancellor
2023-01-12  3:05 ` [PATCH v2 14/14] kbuild: Stop using '-Qunused-arguments' with clang Nathan Chancellor
2023-01-22 17:28 ` [PATCH v2 00/14] Remove clang's -Qunused-arguments from KBUILD_CPPFLAGS Masahiro Yamada
2023-01-22 17:28   ` Masahiro Yamada
2023-01-22 17:28   ` Masahiro Yamada
2023-01-23 13:58 ` Naresh Kamboju
2023-01-23 13:58   ` Naresh Kamboju
2023-01-23 13:58   ` Naresh Kamboju
2023-01-23 16:11   ` Nathan Chancellor
2023-01-23 16:11     ` Nathan Chancellor
2023-01-23 16:11     ` Nathan Chancellor
2023-01-24 15:29     ` Naresh Kamboju
2023-01-24 15:29       ` Naresh Kamboju
2023-01-24 15:29       ` Naresh Kamboju

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20221228-drop-qunused-arguments-v2-8-9adbddd20d86@kernel.org \
    --to=nathan@kernel.org \
    --cc=christophe.leroy@csgroup.eu \
    --cc=linux-kbuild@vger.kernel.org \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=llvm@lists.linux.dev \
    --cc=masahiroy@kernel.org \
    --cc=mpe@ellerman.id.au \
    --cc=ndesaulniers@google.com \
    --cc=nicolas@fjasle.eu \
    --cc=npiggin@gmail.com \
    --cc=trix@redhat.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.