diff --git a/arch/powerpc/Kbuild b/arch/powerpc/Kbuild
index da862e9558bc..571f260b0842 100644
--- a/arch/powerpc/Kbuild
+++ b/arch/powerpc/Kbuild
@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
-subdir-ccflags-$(CONFIG_PPC_WERROR) := -Werror -Wa,-fatal-warnings
-subdir-asflags-$(CONFIG_PPC_WERROR) := -Wa,-fatal-warnings
+subdir-ccflags-$(CONFIG_PPC_WERROR) := -Werror -Wa,--fatal-warnings
+subdir-asflags-$(CONFIG_PPC_WERROR) := -Wa,--fatal-warnings
 
 obj-y += kernel/
 obj-y += mm/