From 40d04110f87940b6a03bf0aa19cd29e84f465f20 Mon Sep 17 00:00:00 2001 From: Marco Elver Date: Thu, 14 Nov 2019 19:03:03 +0100 Subject: x86, kcsan: Enable KCSAN for x86 This patch enables KCSAN for x86, with updates to build rules to not use KCSAN for several incompatible compilation units. Signed-off-by: Marco Elver Acked-by: Paul E. McKenney Signed-off-by: Paul E. McKenney --- arch/x86/purgatory/Makefile | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/x86/purgatory') diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile index fb4ee5444379..69379bce9574 100644 --- a/arch/x86/purgatory/Makefile +++ b/arch/x86/purgatory/Makefile @@ -17,7 +17,9 @@ CFLAGS_sha256.o := -D__DISABLE_EXPORTS LDFLAGS_purgatory.ro := -e purgatory_start -r --no-undefined -nostdlib -z nodefaultlib targets += purgatory.ro +# Sanitizer runtimes are unavailable and cannot be linked here. KASAN_SANITIZE := n +KCSAN_SANITIZE := n KCOV_INSTRUMENT := n # These are adjustments to the compiler flags used for objects that -- cgit v1.2.3 From e2ac07c06058ae2d58b45bbf2a2a352771d76fcb Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Tue, 17 Mar 2020 14:08:40 +0100 Subject: x86/purgatory: Disable various profiling and sanitizing options Since the purgatory is a special stand-alone binary, various profiling and sanitizing options must be disabled. Having these options enabled typically will cause dependencies on various special symbols exported by special libs / stubs used by these frameworks. Since the purgatory is special, it is not linked against these stubs causing missing symbols in the purgatory if these options are not disabled. Sync the set of disabled profiling and sanitizing options with that from drivers/firmware/efi/libstub/Makefile, adding -DDISABLE_BRANCH_PROFILING to the CFLAGS and setting: GCOV_PROFILE := n UBSAN_SANITIZE := n This fixes broken references to ftrace_likely_update() when CONFIG_TRACE_BRANCH_PROFILING is enabled and to __gcov_init() and __gcov_exit() when CONFIG_GCOV_KERNEL is enabled. Signed-off-by: Hans de Goede Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20200317130841.290418-1-hdegoede@redhat.com --- arch/x86/purgatory/Makefile | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'arch/x86/purgatory') diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile index fb4ee5444379..9733d1cc791d 100644 --- a/arch/x86/purgatory/Makefile +++ b/arch/x86/purgatory/Makefile @@ -17,7 +17,10 @@ CFLAGS_sha256.o := -D__DISABLE_EXPORTS LDFLAGS_purgatory.ro := -e purgatory_start -r --no-undefined -nostdlib -z nodefaultlib targets += purgatory.ro +# Sanitizer, etc. runtimes are unavailable and cannot be linked here. +GCOV_PROFILE := n KASAN_SANITIZE := n +UBSAN_SANITIZE := n KCOV_INSTRUMENT := n # These are adjustments to the compiler flags used for objects that @@ -25,7 +28,7 @@ KCOV_INSTRUMENT := n PURGATORY_CFLAGS_REMOVE := -mcmodel=kernel PURGATORY_CFLAGS := -mcmodel=large -ffreestanding -fno-zero-initialized-in-bss -PURGATORY_CFLAGS += $(DISABLE_STACKLEAK_PLUGIN) +PURGATORY_CFLAGS += $(DISABLE_STACKLEAK_PLUGIN) -DDISABLE_BRANCH_PROFILING # Default KBUILD_CFLAGS can have -pg option set when FTRACE is enabled. That # in turn leaves some undefined symbols like __fentry__ in purgatory and not -- cgit v1.2.3 From e4160b2e4b02377c67f8ecd05786811598f39acd Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Tue, 17 Mar 2020 14:08:41 +0100 Subject: x86/purgatory: Fail the build if purgatory.ro has missing symbols Linking purgatory.ro with -r enables "incremental linking"; this means no checks for unresolved symbols are done while linking purgatory.ro. A change 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. Add 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 Also remove --no-undefined from LDFLAGS_purgatory.ro as that has no effect. Signed-off-by: Hans de Goede Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20200317130841.290418-2-hdegoede@redhat.com --- arch/x86/purgatory/.gitignore | 1 + arch/x86/purgatory/Makefile | 13 ++++++++++--- 2 files changed, 11 insertions(+), 3 deletions(-) create mode 100644 arch/x86/purgatory/.gitignore (limited to 'arch/x86/purgatory') diff --git a/arch/x86/purgatory/.gitignore b/arch/x86/purgatory/.gitignore new file mode 100644 index 000000000000..d2be1500671d --- /dev/null +++ b/arch/x86/purgatory/.gitignore @@ -0,0 +1 @@ +purgatory.chk diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile index 9733d1cc791d..54aadbb7e0b6 100644 --- a/arch/x86/purgatory/Makefile +++ b/arch/x86/purgatory/Makefile @@ -14,8 +14,12 @@ $(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 -targets += purgatory.ro +# When linking purgatory.ro with -r unresolved symbols are not checked, +# also link a purgatory.chk binary without -r to check for unresolved symbols. +PURGATORY_LDFLAGS := -e purgatory_start -nostdlib -z nodefaultlib +LDFLAGS_purgatory.ro := -r $(PURGATORY_LDFLAGS) +LDFLAGS_purgatory.chk := $(PURGATORY_LDFLAGS) +targets += purgatory.ro purgatory.chk # Sanitizer, etc. runtimes are unavailable and cannot be linked here. GCOV_PROFILE := n @@ -61,12 +65,15 @@ CFLAGS_string.o += $(PURGATORY_CFLAGS) $(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE $(call if_changed,ld) +$(obj)/purgatory.chk: $(obj)/purgatory.ro FORCE + $(call if_changed,ld) + targets += kexec-purgatory.c quiet_cmd_bin2c = BIN2C $@ cmd_bin2c = $(objtree)/scripts/bin2c kexec_purgatory < $< > $@ -$(obj)/kexec-purgatory.c: $(obj)/purgatory.ro FORCE +$(obj)/kexec-purgatory.c: $(obj)/purgatory.ro $(obj)/purgatory.chk FORCE $(call if_changed,bin2c) obj-$(CONFIG_KEXEC_FILE) += kexec-purgatory.o -- cgit v1.2.3