[PATCH 8/8] x86, kcsan: Enable KCSAN for x86

Marco Elver
2019-10-16T08:41:37Z

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 <elver@google.com>
---
arch/x86/Kconfig | 1 +
arch/x86/boot/Makefile | 1 +
arch/x86/boot/compressed/Makefile | 1 +
arch/x86/entry/vdso/Makefile | 1 +
arch/x86/include/asm/bitops.h | 2 +-
arch/x86/kernel/Makefile | 6 ++++++
arch/x86/kernel/cpu/Makefile | 3 +++
arch/x86/lib/Makefile | 2 ++
arch/x86/mm/Makefile | 3 +++
arch/x86/purgatory/Makefile | 1 +
arch/x86/realmode/Makefile | 1 +
arch/x86/realmode/rm/Makefile | 1 +
drivers/firmware/efi/libstub/Makefile | 1 +
13 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index d6e1faa28c58..81859be4a005 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -226,6 +226,7 @@ config X86
select VIRT_TO_BUS
select X86_FEATURE_NAMES if PROC_FS
select PROC_PID_ARCH_STATUS if PROC_FS
+ select HAVE_ARCH_KCSAN if X86_64

config INSTRUCTION_DECODER
def_bool y
diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile
index e2839b5c246c..2f9e928acae6 100644
--- a/arch/x86/boot/Makefile
+++ b/arch/x86/boot/Makefile
@@ -10,6 +10,7 @@
#

KASAN_SANITIZE := n
+KCSAN_SANITIZE := n
OBJECT_FILES_NON_STANDARD := y

# Kernel does not boot with kcov instrumentation here.
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 6b84afdd7538..0921689f7c70 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -18,6 +18,7 @@
# compressed vmlinux.bin.all + u32 size of vmlinux.bin.all

KASAN_SANITIZE := n
+KCSAN_SANITIZE := n
OBJECT_FILES_NON_STANDARD := y

# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
index 0f2154106d01..d2cd34d2ac4e 100644
--- a/arch/x86/entry/vdso/Makefile
+++ b/arch/x86/entry/vdso/Makefile
@@ -12,6 +12,7 @@ include $(srctree)/lib/vdso/Makefile
KBUILD_CFLAGS += $(DISABLE_LTO)
KASAN_SANITIZE := n
UBSAN_SANITIZE := n
+KCSAN_SANITIZE := n
OBJECT_FILES_NON_STANDARD := y

# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
diff --git a/arch/x86/include/asm/bitops.h b/arch/x86/include/asm/bitops.h
index 7d1f6a49bfae..a36d900960e4 100644
--- a/arch/x86/include/asm/bitops.h
+++ b/arch/x86/include/asm/bitops.h
@@ -201,7 +201,7 @@ arch_test_and_change_bit(long nr, volatile unsigned long *addr)
return GEN_BINARY_RMWcc(LOCK_PREFIX __ASM_SIZE(btc), *addr, c, "Ir", nr);
}

-static __always_inline bool constant_test_bit(long nr, const volatile unsigned long *addr)
+static __no_kcsan_or_inline bool constant_test_bit(long nr, const volatile unsigned long *addr)
{
return ((1UL << (nr & (BITS_PER_LONG-1))) &
(addr[nr >> _BITOPS_LONG_SHIFT])) != 0;
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 3578ad248bc9..adccbbfa47e4 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -28,6 +28,12 @@ KASAN_SANITIZE_dumpstack_$(BITS).o := n
KASAN_SANITIZE_stacktrace.o := n
KASAN_SANITIZE_paravirt.o := n

+KCSAN_SANITIZE_head$(BITS).o := n
+KCSAN_SANITIZE_dumpstack.o := n
+KCSAN_SANITIZE_dumpstack_$(BITS).o := n
+KCSAN_SANITIZE_stacktrace.o := n
+KCSAN_SANITIZE_paravirt.o := n
+
OBJECT_FILES_NON_STANDARD_relocate_kernel_$(BITS).o := y
OBJECT_FILES_NON_STANDARD_test_nx.o := y
OBJECT_FILES_NON_STANDARD_paravirt_patch.o := y
diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile
index d7a1e5a9331c..7651c4f37e5e 100644
--- a/arch/x86/kernel/cpu/Makefile
+++ b/arch/x86/kernel/cpu/Makefile
@@ -3,6 +3,9 @@
# Makefile for x86-compatible CPU details, features and quirks
#

+KCSAN_SANITIZE_common.o = n
+KCSAN_SANITIZE_perf_event.o = n
+
# Don't trace early stages of a secondary CPU boot
ifdef CONFIG_FUNCTION_TRACER
CFLAGS_REMOVE_common.o = -pg
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index 5246db42de45..4e4b74f525f2 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -5,11 +5,13 @@

# Produces uninteresting flaky coverage.
KCOV_INSTRUMENT_delay.o := n
+KCSAN_SANITIZE_delay.o := n

# Early boot use of cmdline; don't instrument it
ifdef CONFIG_AMD_MEM_ENCRYPT
KCOV_INSTRUMENT_cmdline.o := n
KASAN_SANITIZE_cmdline.o := n
+KCSAN_SANITIZE_cmdline.o := n

ifdef CONFIG_FUNCTION_TRACER
CFLAGS_REMOVE_cmdline.o = -pg
diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile
index 84373dc9b341..ee871602f96a 100644
--- a/arch/x86/mm/Makefile
+++ b/arch/x86/mm/Makefile
@@ -7,6 +7,9 @@ KCOV_INSTRUMENT_mem_encrypt_identity.o := n
KASAN_SANITIZE_mem_encrypt.o := n
KASAN_SANITIZE_mem_encrypt_identity.o := n

+KCSAN_SANITIZE_mem_encrypt.o := n
+KCSAN_SANITIZE_mem_encrypt_identity.o := n
+
ifdef CONFIG_FUNCTION_TRACER
CFLAGS_REMOVE_mem_encrypt.o = -pg
CFLAGS_REMOVE_mem_encrypt_identity.o = -pg
diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
index fb4ee5444379..72060744f34f 100644
--- a/arch/x86/purgatory/Makefile
+++ b/arch/x86/purgatory/Makefile
@@ -18,6 +18,7 @@ LDFLAGS_purgatory.ro := -e purgatory_start -r --no-undefined -nostdlib -z nodefa
targets += purgatory.ro

KASAN_SANITIZE := n
+KCSAN_SANITIZE := n
KCOV_INSTRUMENT := n

# These are adjustments to the compiler flags used for objects that
diff --git a/arch/x86/realmode/Makefile b/arch/x86/realmode/Makefile
index 682c895753d9..4fc7ce2534dd 100644
--- a/arch/x86/realmode/Makefile
+++ b/arch/x86/realmode/Makefile
@@ -7,6 +7,7 @@
#
#
KASAN_SANITIZE := n
+KCSAN_SANITIZE := n
OBJECT_FILES_NON_STANDARD := y

subdir- := rm
diff --git a/arch/x86/realmode/rm/Makefile b/arch/x86/realmode/rm/Makefile
index f60501a384f9..6f7fbe9dfda6 100644
--- a/arch/x86/realmode/rm/Makefile
+++ b/arch/x86/realmode/rm/Makefile
@@ -7,6 +7,7 @@
#
#
KASAN_SANITIZE := n
+KCSAN_SANITIZE := n
OBJECT_FILES_NON_STANDARD := y

# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index 0460c7581220..a56981286623 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -32,6 +32,7 @@ KBUILD_CFLAGS := $(cflags-y) -DDISABLE_BRANCH_PROFILING \

GCOV_PROFILE := n
KASAN_SANITIZE := n
+KCSAN_SANITIZE := n
UBSAN_SANITIZE := n
OBJECT_FILES_NON_STANDARD := y

--
2.23.0.700.g56cf767bdb-goog