FAILED: patch "[PATCH] kbuild: Disable -Wpointer-to-enum-cast" failed to apply to 4.19-stable tree

PATCH Applied [email protected] 3 participants 3 messages Mar 23, 2020

Subsystems (2)

Stable branch Kbuild

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[email protected]

author maintainer

2020-03-23 14:28 UTC #0 lore raw

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 82f2bc2fcc0160d6f82dd1ac64518ae0a4dd183f Mon Sep 17 00:00:00 2001
From: Nathan Chancellor <[email protected]>
Date: Wed, 11 Mar 2020 12:41:21 -0700
Subject: [PATCH] kbuild: Disable -Wpointer-to-enum-cast

Clang's -Wpointer-to-int-cast deviates from GCC in that it warns when casting to enums. The kernel does this in certain places, such as device tree matches to set the version of the device being used, which allows the kernel to avoid using a gigantic union.

https://elixir.bootlin.com/linux/v5.5.8/source/drivers/ata/ahci_brcm.c#L428
https://elixir.bootlin.com/linux/v5.5.8/source/drivers/ata/ahci_brcm.c#L402
https://elixir.bootlin.com/linux/v5.5.8/source/include/linux/mod_devicetable.h#L264

To avoid a ton of false positive warnings, disable this particular part of the warning, which has been split off into a separate diagnostic so that the entire warning does not need to be turned off for clang. It will be visible under W=1 in case people want to go about fixing these easily and enabling the warning treewide.

Cc [email protected]

Link https://github.com/ClangBuiltLinux/linux/issues/887

Link https://github.com/llvm/llvm-project/commit/2a41b31fcdfcb67ab7038fc2ffb606fd50b83a84

Signed-off-by Nathan Chancellor <[email protected]>

Signed-off-by Masahiro Yamada <[email protected]>

scripts/Makefile.extrawarn +1 -0

index ecddf83ac142..ca08f2fe7c34 100644
@@ -48,6 +48,7 @@ KBUILD_CFLAGS += -Wno-initializer-overrides
 KBUILD_CFLAGS += -Wno-format
 KBUILD_CFLAGS += -Wno-sign-compare
 KBUILD_CFLAGS += -Wno-format-zero-length
+KBUILD_CFLAGS += $(call cc-disable-warning, pointer-to-enum-cast)
 endif
 
 endif

Nathan Chancellor

2020-03-23 15:34 UTC #1 lore raw

Quoted 44 lines · On Mon, Mar 23, 2020 at 03:28:48PM +0100, [email protected] wrote:

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 82f2bc2fcc0160d6f82dd1ac64518ae0a4dd183f Mon Sep 17 00:00:00 2001
From: Nathan Chancellor <[email protected]>
Date: Wed, 11 Mar 2020 12:41:21 -0700
Subject: [PATCH] kbuild: Disable -Wpointer-to-enum-cast
Clang's -Wpointer-to-int-cast deviates from GCC in that it warns when casting to enums. The kernel does this in certain places, such as device tree matches to set the version of the device being used, which allows the kernel to avoid using a gigantic union.
https://elixir.bootlin.com/linux/v5.5.8/source/drivers/ata/ahci_brcm.c#L428
https://elixir.bootlin.com/linux/v5.5.8/source/drivers/ata/ahci_brcm.c#L402
https://elixir.bootlin.com/linux/v5.5.8/source/include/linux/mod_devicetable.h#L264
To avoid a ton of false positive warnings, disable this particular part of the warning, which has been split off into a separate diagnostic so that the entire warning does not need to be turned off for clang. It will be visible under W=1 in case people want to go about fixing these easily and enabling the warning treewide.
Cc [email protected]
Link https://github.com/ClangBuiltLinux/linux/issues/887
Link https://github.com/llvm/llvm-project/commit/2a41b31fcdfcb67ab7038fc2ffb606fd50b83a84
Signed-off-by Nathan Chancellor <[email protected]>
Signed-off-by Masahiro Yamada <[email protected]>
scripts/Makefile.extrawarn +0 -0
index ecddf83ac142..ca08f2fe7c34 100644

scripts/Makefile.extrawarn KBUILD_CFLAGS += -Wno-initializer-overrides · line 54

Quoted 7 lines

scripts/Makefile.extrawarn +1 -0

@@ -48,6 +48,7 @@ KBUILD_CFLAGS += -Wno-initializer-overrides
 KBUILD_CFLAGS += -Wno-format
 KBUILD_CFLAGS += -Wno-sign-compare
 KBUILD_CFLAGS += -Wno-format-zero-length
+KBUILD_CFLAGS += $(call cc-disable-warning, pointer-to-enum-cast)
 endif
 
 endif

Attached is a backport that should work for 4.4 through 4.19.

Cheers,
Nathan

From 03368599bf131e92c660d884c84a648f387c89ae Mon Sep 17 00:00:00 2001
From: Nathan Chancellor <[email protected]>
Date: Wed, 11 Mar 2020 12:41:21 -0700
Subject: [PATCH] kbuild: Disable -Wpointer-to-enum-cast

commit 82f2bc2fcc0160d6f82dd1ac64518ae0a4dd183f upstream.

Cc [email protected]

Link https://github.com/ClangBuiltLinux/linux/issues/887

Link https://github.com/llvm/llvm-project/commit/2a41b31fcdfcb67ab7038fc2ffb606fd50b83a84

Signed-off-by Nathan Chancellor <[email protected]>

Signed-off-by Masahiro Yamada <[email protected]>

---
 scripts/Makefile.extrawarn | 1 +
 1 file changed, 1 insertion(+)

scripts/Makefile.extrawarn +1 -0

index 8d5357053f86..486e135d3e30 100644
@@ -72,5 +72,6 @@ KBUILD_CFLAGS += $(call cc-disable-warning, format)
 KBUILD_CFLAGS += $(call cc-disable-warning, sign-compare)
 KBUILD_CFLAGS += $(call cc-disable-warning, format-zero-length)
 KBUILD_CFLAGS += $(call cc-disable-warning, uninitialized)
+KBUILD_CFLAGS += $(call cc-disable-warning, pointer-to-enum-cast)
 endif
 endif

Signature · 1 line

2.26.0

Sasha Levin

maintainer Applied

2020-03-23 16:36 UTC #2 lore raw

Quoted 50 lines · Nathan Chancellor

Quoted 49 lines · On Mon, Mar 23, 2020 at 03:28:48PM +0100, [email protected] wrote:
The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 82f2bc2fcc0160d6f82dd1ac64518ae0a4dd183f Mon Sep 17 00:00:00 2001
From: Nathan Chancellor <[email protected]>
Date: Wed, 11 Mar 2020 12:41:21 -0700
Subject: [PATCH] kbuild: Disable -Wpointer-to-enum-cast
Clang's -Wpointer-to-int-cast deviates from GCC in that it warns when casting to enums. The kernel does this in certain places, such as device tree matches to set the version of the device being used, which allows the kernel to avoid using a gigantic union.
https://elixir.bootlin.com/linux/v5.5.8/source/drivers/ata/ahci_brcm.c#L428
https://elixir.bootlin.com/linux/v5.5.8/source/drivers/ata/ahci_brcm.c#L402
https://elixir.bootlin.com/linux/v5.5.8/source/include/linux/mod_devicetable.h#L264
To avoid a ton of false positive warnings, disable this particular part of the warning, which has been split off into a separate diagnostic so that the entire warning does not need to be turned off for clang. It will be visible under W=1 in case people want to go about fixing these easily and enabling the warning treewide.
Cc [email protected]
Link https://github.com/ClangBuiltLinux/linux/issues/887
Link https://github.com/llvm/llvm-project/commit/2a41b31fcdfcb67ab7038fc2ffb606fd50b83a84
Signed-off-by Nathan Chancellor <[email protected]>
Signed-off-by Masahiro Yamada <[email protected]>
scripts/Makefile.extrawarn +1 -0
index ecddf83ac142..ca08f2fe7c34 100644
@@ -48,6 +48,7 @@ KBUILD_CFLAGS += -Wno-initializer-overrides
 KBUILD_CFLAGS += -Wno-format
 KBUILD_CFLAGS += -Wno-sign-compare
 KBUILD_CFLAGS += -Wno-format-zero-length
+KBUILD_CFLAGS += $(call cc-disable-warning, pointer-to-enum-cast)
 endif
 

Quoted 4 lines

scripts/Makefile.extrawarn KBUILD_CFLAGS += -Wno-initializer-overrides · line 54
Quoted 2 lines
scripts/Makefile.extrawarn +0 -0
 endif
Attached is a backport that should work for 4.4 through 4.19.

Queued up, thanks!

Signature · 2 lines

Thanks,
Sasha