From: Hans de Goede <hdegoede@redhat.com>
To: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H . Peter Anvin" <hpa@zytor.com>
Cc: Hans de Goede <hdegoede@redhat.com>,
Arvind Sankar <nivedita@alum.mit.edu>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] x86/purgatory: Make sure we fail the build if purgatory.ro has missing symbols
Date: Mon, 7 Oct 2019 19:55:46 +0200 [thread overview]
Message-ID: <20191007175546.3395-1-hdegoede@redhat.com> (raw)
Since we link purgatory.ro with -r aka we enable "incremental linking"
no checks for unresolved symbols is done while linking purgatory.ro.
Changes to the sha256 code has caused the purgatory in 5.4-rc1 to have
a missing symbol on memzero_explicit, yet things still happily build.
This commit adds an extra check for unresolved symbols by calling ld
without -r before running bin2c to generate kexec-purgatory.c.
This causes a build of 5.4-rc1 with this patch added to fail as it should:
CHK arch/x86/purgatory/purgatory.ro
ld: arch/x86/purgatory/purgatory.ro: in function `sha256_transform':
sha256.c:(.text+0x1c0c): undefined reference to `memzero_explicit'
make[2]: *** [arch/x86/purgatory/Makefile:72:
arch/x86/purgatory/kexec-purgatory.c] Error 1
make[1]: *** [scripts/Makefile.build:509: arch/x86/purgatory] Error 2
make: *** [Makefile:1650: arch/x86] Error 2
This will help us catch missing symbols in the purgatory sooner.
Note this commit also removes --no-undefined from LDFLAGS_purgatory.ro
as that has no effect.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
arch/x86/purgatory/Makefile | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
index fb4ee5444379..0da0794ef1f0 100644
--- a/arch/x86/purgatory/Makefile
+++ b/arch/x86/purgatory/Makefile
@@ -14,7 +14,7 @@ $(obj)/sha256.o: $(srctree)/lib/crypto/sha256.c FORCE
CFLAGS_sha256.o := -D__DISABLE_EXPORTS
-LDFLAGS_purgatory.ro := -e purgatory_start -r --no-undefined -nostdlib -z nodefaultlib
+LDFLAGS_purgatory.ro := -e purgatory_start -r -nostdlib -z nodefaultlib
targets += purgatory.ro
KASAN_SANITIZE := n
@@ -60,10 +60,16 @@ $(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE
targets += kexec-purgatory.c
+# Since we link purgatory.ro with -r unresolved symbols are not checked,
+# so we check this before generating kexec-purgatory.c instead
+quiet_cmd_check_purgatory = CHK $<
+ cmd_check_purgatory = ld -e purgatory_start $<
+
quiet_cmd_bin2c = BIN2C $@
cmd_bin2c = $(objtree)/scripts/bin2c kexec_purgatory < $< > $@
$(obj)/kexec-purgatory.c: $(obj)/purgatory.ro FORCE
+ $(call if_changed,check_purgatory)
$(call if_changed,bin2c)
obj-$(CONFIG_KEXEC_FILE) += kexec-purgatory.o
--
2.23.0
next reply other threads:[~2019-10-07 17:55 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-07 17:55 Hans de Goede [this message]
2019-10-07 20:05 ` [PATCH] x86/purgatory: Make sure we fail the build if purgatory.ro has missing symbols Nathan Chancellor
2019-10-07 20:31 ` Hans de Goede
2019-10-07 21:52 ` Arvind Sankar
2019-10-08 5:57 ` Hans de Goede
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