From: Linus Torvalds torvalds@linux-foundation.org
[ Upstream commit 42e0e95474fc6076b5cd68cab8fa0340a1797a72 ]
One of the very few warnings I have in the current build comes from arch/x86/boot/edd.c, where I get the following with a gcc9 build:
arch/x86/boot/edd.c: In function ‘query_edd’: arch/x86/boot/edd.c:148:11: warning: taking address of packed member of ‘struct boot_params’ may result in an unaligned pointer value [-Waddress-of-packed-member] 148 | mbrptr = boot_params.edd_mbr_sig_buffer; | ^~~~~~~~~~~
This warning triggers because we throw away all the CFLAGS and then make a new set for REALMODE_CFLAGS, so the -Wno-address-of-packed-member we added in the following commit is not present:
6f303d60534c ("gcc-9: silence 'address-of-packed-member' warning")
The simplest solution for now is to adjust the warning for this version of CFLAGS as well, but it would definitely make sense to examine whether REALMODE_CFLAGS could be derived from CFLAGS, so that it picks up changes in the compiler flags environment automatically.
Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Acked-by: Borislav Petkov bp@alien8.de Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/Makefile | 1 + 1 file changed, 1 insertion(+)
diff --git a/arch/x86/Makefile b/arch/x86/Makefile index b4c72da8a7adb..cd596ca609010 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -39,6 +39,7 @@ REALMODE_CFLAGS := $(M16_CFLAGS) -g -Os -D__KERNEL__ \
REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -ffreestanding) REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -fno-stack-protector) +REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -Wno-address-of-packed-member) REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), $(cc_stack_align4)) export REALMODE_CFLAGS