[PATCH 1/4] [v4] Kbuild: add -Wno-shift-negative-value where -Wextra is used

Arnd Bergmann
2022-03-08T21:57:07Z

From: Arnd Bergmann <arnd@arndb.de>

As a preparation for moving to -std=gnu11, turn off the
-Wshift-negative-value option. This warning is enabled by gcc when
building with -Wextra for c99 or higher, but not for c89. Since
the kernel already relies on well-defined overflow behavior,
the warning is not helpful and can simply be disabled in
all locations that use -Wextra.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
[v4]
split into a separate patch
---
drivers/gpu/drm/i915/Makefile | 1 +
drivers/staging/greybus/tools/Makefile | 3 ++-
fs/btrfs/Makefile | 1 +
scripts/Makefile.extrawarn | 1 +
4 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 1b62b9f65196..1618a6e0af4e 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -17,6 +17,7 @@ subdir-ccflags-y += -Wno-unused-parameter
subdir-ccflags-y += -Wno-type-limits
subdir-ccflags-y += -Wno-missing-field-initializers
subdir-ccflags-y += -Wno-sign-compare
+subdir-ccflags-y += -Wno-shift-negative-value
subdir-ccflags-y += $(call cc-disable-warning, unused-but-set-variable)
subdir-ccflags-y += $(call cc-disable-warning, frame-address)
subdir-ccflags-$(CONFIG_DRM_I915_WERROR) += -Werror
diff --git a/drivers/staging/greybus/tools/Makefile b/drivers/staging/greybus/tools/Makefile
index ad0ae8053b79..a3bbd73171f2 100644
--- a/drivers/staging/greybus/tools/Makefile
+++ b/drivers/staging/greybus/tools/Makefile
@@ -12,7 +12,8 @@ CFLAGS += -std=gnu99 -Wall -Wextra -g \
-Wredundant-decls \
-Wcast-align \
-Wsign-compare \
- -Wno-missing-field-initializers
+ -Wno-missing-field-initializers \
+ -Wno-shift-negative-value

CC := $(CROSS_COMPILE)gcc

diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
index 4188ba3fd8c3..99f9995670ea 100644
--- a/fs/btrfs/Makefile
+++ b/fs/btrfs/Makefile
@@ -17,6 +17,7 @@ subdir-ccflags-y += $(condflags)
subdir-ccflags-y += -Wno-missing-field-initializers
subdir-ccflags-y += -Wno-sign-compare
subdir-ccflags-y += -Wno-type-limits
+subdir-ccflags-y += -Wno-shift-negative-value

obj-$(CONFIG_BTRFS_FS) := btrfs.o

diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn
index 8be892887d71..650d0b8ceec3 100644
--- a/scripts/Makefile.extrawarn
+++ b/scripts/Makefile.extrawarn
@@ -36,6 +36,7 @@ KBUILD_CFLAGS += $(call cc-option, -Wstringop-truncation)
KBUILD_CFLAGS += -Wno-missing-field-initializers
KBUILD_CFLAGS += -Wno-sign-compare
KBUILD_CFLAGS += -Wno-type-limits
+KBUILD_CFLAGS += -Wno-shift-negative-value

KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN1

--
2.29.2