Re: [PATCH] x86/purgatory: Make sure we fail the build if purgatory.ro has missing symbols
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 --- 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
Re: [PATCH] x86/purgatory: Make sure we fail the build if purgatory.ro has missing symbols
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 > >> --- > >> 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?
Re: [PATCH] x86/purgatory: Make sure we fail the build if purgatory.ro has missing symbols
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 --- 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
Re: [PATCH] x86/purgatory: Make sure we fail the build if purgatory.ro has missing symbols
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 > --- > 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
[PATCH] x86/purgatory: Make sure we fail the build if purgatory.ro has missing symbols
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 --- 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
