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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Borislav Petkov <bp@alien8.de>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@kernel.org>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH AUTOSEL 4.9 20/27] x86/build: Add -Wnoaddress-of-packed-member to REALMODE_CFLAGS, to silence GCC9 build warning
Date: Wed,  4 Sep 2019 12:02:13 -0400	[thread overview]
Message-ID: <20190904160220.4545-20-sashal@kernel.org> (raw)
In-Reply-To: <20190904160220.4545-1-sashal@kernel.org>

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 2996a1d0a410a..940ed27a62123 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -38,6 +38,7 @@ 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
 
-- 
2.20.1


  parent reply	other threads:[~2019-09-04 16:05 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-04 16:01 [PATCH AUTOSEL 4.9 01/27] ARM: OMAP2+: Fix missing SYSC_HAS_RESET_STATUS for dra7 epwmss Sasha Levin
2019-09-04 16:01 ` [PATCH AUTOSEL 4.9 02/27] s390/bpf: fix lcgr instruction encoding Sasha Levin
2019-09-04 16:01 ` [PATCH AUTOSEL 4.9 03/27] ARM: OMAP2+: Fix omap4 errata warning on other SoCs Sasha Levin
2019-09-04 16:01 ` [PATCH AUTOSEL 4.9 04/27] s390/bpf: use 32-bit index for tail calls Sasha Levin
2019-09-04 16:01 ` [PATCH AUTOSEL 4.9 05/27] batman-adv: fix uninit-value in batadv_netlink_get_ifindex() Sasha Levin
2019-09-04 16:01 ` [PATCH AUTOSEL 4.9 06/27] NFSv4: Fix return values for nfs4_file_open() Sasha Levin
2019-09-04 16:02 ` [PATCH AUTOSEL 4.9 07/27] NFS: Fix initialisation of I/O result struct in nfs_pgio_rpcsetup Sasha Levin
2019-09-04 16:02 ` [PATCH AUTOSEL 4.9 08/27] Kconfig: Fix the reference to the IDT77105 Phy driver in the description of ATM_NICSTAR_USE_IDT77105 Sasha Levin
2019-09-04 16:02 ` [PATCH AUTOSEL 4.9 09/27] qed: Add cleanup in qed_slowpath_start() Sasha Levin
2019-09-04 16:02 ` [PATCH AUTOSEL 4.9 10/27] ARM: 8874/1: mm: only adjust sections of valid mm structures Sasha Levin
2019-09-04 16:02 ` [PATCH AUTOSEL 4.9 11/27] batman-adv: Only read OGM tvlv_len after buffer len check Sasha Levin
2019-09-04 16:02 ` [PATCH AUTOSEL 4.9 12/27] batman-adv: Only read OGM2 " Sasha Levin
2019-09-04 16:02 ` [PATCH AUTOSEL 4.9 13/27] r8152: Set memory to all 0xFFs on failed reg reads Sasha Levin
2019-09-04 16:02 ` [PATCH AUTOSEL 4.9 14/27] x86/apic: Fix arch_dynirq_lower_bound() bug for DT enabled machines Sasha Levin
2019-09-04 16:02 ` [PATCH AUTOSEL 4.9 15/27] netfilter: nf_conntrack_ftp: Fix debug output Sasha Levin
2019-09-04 16:02 ` [PATCH AUTOSEL 4.9 16/27] NFSv2: Fix eof handling Sasha Levin
2019-09-04 16:02 ` [PATCH AUTOSEL 4.9 17/27] NFSv2: Fix write regression Sasha Levin
2019-09-04 16:02 ` [PATCH AUTOSEL 4.9 18/27] cifs: set domainName when a domain-key is used in multiuser Sasha Levin
2019-09-04 16:02 ` [PATCH AUTOSEL 4.9 19/27] cifs: Use kzfree() to zero out the password Sasha Levin
2019-09-04 16:02 ` Sasha Levin [this message]
2019-09-04 16:02 ` [PATCH AUTOSEL 4.9 21/27] ARM: 8901/1: add a criteria for pfn_valid of arm Sasha Levin
2019-09-04 16:02 ` [PATCH AUTOSEL 4.9 22/27] sky2: Disable MSI on yet another ASUS boards (P6Xxxx) Sasha Levin
2019-09-04 16:02 ` [PATCH AUTOSEL 4.9 23/27] perf/x86/intel: Restrict period on Nehalem Sasha Levin
2019-09-04 16:02 ` [PATCH AUTOSEL 4.9 24/27] perf/x86/amd/ibs: Fix sample bias for dispatched micro-ops Sasha Levin
2019-09-04 16:02 ` [PATCH AUTOSEL 4.9 25/27] net: stmmac: dwmac-rk: Don't fail if phy regulator is absent Sasha Levin
2019-09-04 16:02 ` [PATCH AUTOSEL 4.9 26/27] tools/power turbostat: fix buffer overrun Sasha Levin
2019-09-04 16:02 ` [PATCH AUTOSEL 4.9 27/27] net: seeq: Fix the function used to release some memory in an error handling path Sasha Levin

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