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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 <elver@google.com>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Marco Elver 2019-11-14 19:03:03 +01:00 committed by Paul E. McKenney
parent e75a6795ed
commit 40d04110f8
12 changed files with 36 additions and 1 deletions
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1
arch/x86/Kconfig
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@ -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

2
arch/x86/boot/Makefile
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@ -9,7 +9,9 @@
# Changed by many, many contributors over the years.
#
# Sanitizer runtimes are unavailable and cannot be linked for early boot code.
KASAN_SANITIZE := n
KCSAN_SANITIZE := n
OBJECT_FILES_NON_STANDARD := y
# Kernel does not boot with kcov instrumentation here.

2
arch/x86/boot/compressed/Makefile
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@ -17,7 +17,9 @@
# (see scripts/Makefile.lib size_append)
# compressed vmlinux.bin.all + u32 size of vmlinux.bin.all
# Sanitizer runtimes are unavailable and cannot be linked for early boot code.
KASAN_SANITIZE := n
KCSAN_SANITIZE := n
OBJECT_FILES_NON_STANDARD := y
# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.

3
arch/x86/entry/vdso/Makefile
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@ -10,8 +10,11 @@ ARCH_REL_TYPE_ABS += R_386_GLOB_DAT|R_386_JMP_SLOT|R_386_RELATIVE
include $(srctree)/lib/vdso/Makefile
KBUILD_CFLAGS += $(DISABLE_LTO)
# Sanitizer runtimes are unavailable and cannot be linked here.
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.

6
arch/x86/include/asm/bitops.h
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@ -201,8 +201,12 @@ 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)
{
/*
* Because this is a plain access, we need to disable KCSAN here to
* avoid double instrumentation via instrumented bitops.
*/
return ((1UL << (nr & (BITS_PER_LONG-1))) &
(addr[nr >> _BITOPS_LONG_SHIFT])) != 0;
}

4
arch/x86/kernel/Makefile
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@ -28,6 +28,10 @@ KASAN_SANITIZE_dumpstack_$(BITS).o := n
KASAN_SANITIZE_stacktrace.o := n
KASAN_SANITIZE_paravirt.o := n
# With some compiler versions the generated code results in boot hangs, caused
# by several compilation units. To be safe, disable all instrumentation.
KCSAN_SANITIZE := n
OBJECT_FILES_NON_STANDARD_relocate_kernel_$(BITS).o := y
OBJECT_FILES_NON_STANDARD_test_nx.o := y
OBJECT_FILES_NON_STANDARD_paravirt_patch.o := y

3
arch/x86/kernel/cpu/Makefile
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@ -13,6 +13,9 @@ endif
KCOV_INSTRUMENT_common.o := n
KCOV_INSTRUMENT_perf_event.o := n
# As above, instrumenting secondary CPU boot code causes boot hangs.
KCSAN_SANITIZE_common.o := n
# Make sure load_percpu_segment has no stackprotector
nostackp := $(call cc-option, -fno-stack-protector)
CFLAGS_common.o := $(nostackp)

4
arch/x86/lib/Makefile
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@ -6,10 +6,14 @@
# Produces uninteresting flaky coverage.
KCOV_INSTRUMENT_delay.o := n
# KCSAN uses udelay for introducing watchpoint delay; avoid recursion.
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

4
arch/x86/mm/Makefile
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@ -7,6 +7,10 @@ KCOV_INSTRUMENT_mem_encrypt_identity.o := n
KASAN_SANITIZE_mem_encrypt.o := n
KASAN_SANITIZE_mem_encrypt_identity.o := n
# Disable KCSAN entirely, because otherwise we get warnings that some functions
# reference __initdata sections.
KCSAN_SANITIZE := n
ifdef CONFIG_FUNCTION_TRACER
CFLAGS_REMOVE_mem_encrypt.o = -pg
CFLAGS_REMOVE_mem_encrypt_identity.o = -pg

2
arch/x86/purgatory/Makefile
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@ -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

3
arch/x86/realmode/Makefile
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@ -6,7 +6,10 @@
# for more details.
#
#
# Sanitizer runtimes are unavailable and cannot be linked here.
KASAN_SANITIZE := n
KCSAN_SANITIZE := n
OBJECT_FILES_NON_STANDARD := y
subdir- := rm

3
arch/x86/realmode/rm/Makefile
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@ -6,7 +6,10 @@
# for more details.
#
#
# Sanitizer runtimes are unavailable and cannot be linked here.
KASAN_SANITIZE := n
KCSAN_SANITIZE := n
OBJECT_FILES_NON_STANDARD := y
# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.