From: Linus Torvalds <[email protected]>
commit 42e0e95474fc6076b5cd68cab8fa0340a1797a72 upstream.
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 <[email protected]>
Acked-by: Borislav Petkov <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/Makefile | 1 +
1 file changed, 1 insertion(+)
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -38,6 +38,7 @@ REALMODE_CFLAGS := $(M16_CFLAGS) -g -Os
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
