Commit 40d04110 authored by Marco Elver's avatar Marco Elver Committed by Paul E. McKenney
Browse files

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: default avatarMarco Elver <elver@google.com>
Acked-by: default avatarPaul E. McKenney <paulmck@kernel.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent e75a6795

arch/x86/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -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

arch/x86/boot/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -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.

arch/x86/boot/compressed/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -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.

arch/x86/entry/vdso/Makefile

+3 −0
Original line number Diff line number Diff line
@@ -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.

arch/x86/include/asm/bitops.h

+5 −1
Original line number Diff line number Diff line
@@ -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;

}