* [PATCH] x86/purgatory: Make sure we fail the build if purgatory.ro has missing symbols
@ 2019-10-07 17:55 Hans de Goede
2019-10-07 20:05 ` Nathan Chancellor
0 siblings, 1 reply; 5+ messages in thread
From: Hans de Goede @ 2019-10-07 17:55 UTC (permalink / raw)
To: Thomas Gleixner, Ingo Molnar, Borislav Petkov, H . Peter Anvin
Cc: Hans de Goede, Arvind Sankar, x86, linux-kernel
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
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] x86/purgatory: Make sure we fail the build if purgatory.ro has missing symbols 2019-10-07 17:55 [PATCH] x86/purgatory: Make sure we fail the build if purgatory.ro has missing symbols Hans de Goede @ 2019-10-07 20:05 ` Nathan Chancellor 2019-10-07 20:31 ` Hans de Goede 0 siblings, 1 reply; 5+ messages in thread From: Nathan Chancellor @ 2019-10-07 20:05 UTC (permalink / raw) To: Hans de Goede Cc: Thomas Gleixner, Ingo Molnar, Borislav Petkov, H . Peter Anvin, Arvind Sankar, x86, linux-kernel, clang-built-linux On Mon, Oct 07, 2019 at 07:55:46PM +0200, Hans de Goede wrote: > 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 $< I think this should be $(LD) -e ... so that using a cross compile prefix (like x86_64-linux-) or an alternative linker like ld.lld works properly. > + > 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 > Cheers, Nathan ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] x86/purgatory: Make sure we fail the build if purgatory.ro has missing symbols 2019-10-07 20:05 ` Nathan Chancellor @ 2019-10-07 20:31 ` Hans de Goede 2019-10-07 21:52 ` Arvind Sankar 0 siblings, 1 reply; 5+ messages in thread From: Hans de Goede @ 2019-10-07 20:31 UTC (permalink / raw) To: Nathan Chancellor Cc: Thomas Gleixner, Ingo Molnar, Borislav Petkov, H . Peter Anvin, Arvind Sankar, x86, linux-kernel, clang-built-linux HI, On 07-10-2019 22:05, Nathan Chancellor wrote: > On Mon, Oct 07, 2019 at 07:55:46PM +0200, Hans de Goede wrote: >> 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 $< > > I think this should be $(LD) -e ... so that using a cross compile prefix > (like x86_64-linux-) or an alternative linker like ld.lld works properly. Good point, also the ld command is actually outputting an a.out file which is also something which we do not want. I will prepare a new version fixing both. Regards, Hans ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] x86/purgatory: Make sure we fail the build if purgatory.ro has missing symbols 2019-10-07 20:31 ` Hans de Goede @ 2019-10-07 21:52 ` Arvind Sankar 2019-10-08 5:57 ` Hans de Goede 0 siblings, 1 reply; 5+ messages in thread From: Arvind Sankar @ 2019-10-07 21:52 UTC (permalink / raw) To: Hans de Goede Cc: Nathan Chancellor, Thomas Gleixner, Ingo Molnar, Borislav Petkov, H . Peter Anvin, Arvind Sankar, x86, linux-kernel, clang-built-linux On Mon, Oct 07, 2019 at 10:31:49PM +0200, Hans de Goede wrote: > HI, > > On 07-10-2019 22:05, Nathan Chancellor wrote: > > On Mon, Oct 07, 2019 at 07:55:46PM +0200, Hans de Goede wrote: > >> 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 $< > > > > I think this should be $(LD) -e ... so that using a cross compile prefix > > (like x86_64-linux-) or an alternative linker like ld.lld works properly. > > Good point, also the ld command is actually outputting an a.out file > which is also something which we do not want. > > I will prepare a new version fixing both. > > Regards, > > Hans We could just use $(NM) -u, right? ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] x86/purgatory: Make sure we fail the build if purgatory.ro has missing symbols 2019-10-07 21:52 ` Arvind Sankar @ 2019-10-08 5:57 ` Hans de Goede 0 siblings, 0 replies; 5+ messages in thread From: Hans de Goede @ 2019-10-08 5:57 UTC (permalink / raw) To: Arvind Sankar Cc: Nathan Chancellor, Thomas Gleixner, Ingo Molnar, Borislav Petkov, H . Peter Anvin, x86, linux-kernel, clang-built-linux HI, On 07-10-2019 23:52, Arvind Sankar wrote: > On Mon, Oct 07, 2019 at 10:31:49PM +0200, Hans de Goede wrote: >> HI, >> >> On 07-10-2019 22:05, Nathan Chancellor wrote: >>> On Mon, Oct 07, 2019 at 07:55:46PM +0200, Hans de Goede wrote: >>>> 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 $< >>> >>> I think this should be $(LD) -e ... so that using a cross compile prefix >>> (like x86_64-linux-) or an alternative linker like ld.lld works properly. >> >> Good point, also the ld command is actually outputting an a.out file >> which is also something which we do not want. >> >> I will prepare a new version fixing both. >> >> Regards, >> >> Hans > > We could just use $(NM) -u, right? That would require wrapping it in some shell code like this (untested): SHOULD_BE_EMPTY=$(nm -u purgatory.ro); if [ "$SHOULD_BE_EMPTY" == "" ]; then true; else false; fi And then escaping the $ in there and in injecting $(NM) into it, IMHO it is easier to just do: $(LD) $PURGATORY_LDFLAGS) purgatory.ro -o /dev/null Also it seems better to actually use the linker for this test then usig an other tool which may have subtly different semantics. Regards, Hans ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2019-10-08 5:57 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2019-10-07 17:55 [PATCH] x86/purgatory: Make sure we fail the build if purgatory.ro has missing symbols Hans de Goede 2019-10-07 20:05 ` 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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