Commit c0dd6716 authored by Josh Poimboeuf's avatar Josh Poimboeuf Committed by Ingo Molnar
Browse files

objtool: Mark non-standard object files and directories 



Code which runs outside the kernel's normal mode of operation often does
unusual things which can cause a static analysis tool like objtool to
emit false positive warnings:

 - boot image
 - vdso image
 - relocation
 - realmode
 - efi
 - head
 - purgatory
 - modpost

Set OBJECT_FILES_NON_STANDARD for their related files and directories,
which will tell objtool to skip checking them.  It's ok to skip them
because they don't affect runtime stack traces.

Also skip the following code which does the right thing with respect to
frame pointers, but is too "special" to be validated by a tool:

 - entry
 - mcount

Also skip the test_nx module because it modifies its exception handling
table at runtime, which objtool can't understand.  Fortunately it's
just a test module so it doesn't matter much.

Currently objtool is the only user of OBJECT_FILES_NON_STANDARD, but it
might eventually be useful for other tools.

Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris J Arges <chris.j.arges@canonical.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/366c080e3844e8a5b6a0327dc7e8c2b90ca3baeb.1456719558.git.jpoimboe@redhat.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 319e305c

arch/x86/boot/Makefile

+2 −1
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 
#



KASAN_SANITIZE			:= n

OBJECT_FILES_NON_STANDARD	:= y



# If you want to preset the SVGA mode, uncomment the next line and

# set SVGA_MODE to whatever number you want.

arch/x86/boot/compressed/Makefile

+2 −1
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#	compressed vmlinux.bin.all + u32 size of vmlinux.bin.all



KASAN_SANITIZE			:= n

OBJECT_FILES_NON_STANDARD	:= y



targets := vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma \

	vmlinux.bin.xz vmlinux.bin.lzo vmlinux.bin.lz4

arch/x86/entry/Makefile

+4 −0
Original line number Diff line number Diff line 
#

# Makefile for the x86 low level entry code

#



OBJECT_FILES_NON_STANDARD_entry_$(BITS).o   := y

OBJECT_FILES_NON_STANDARD_entry_64_compat.o := y



obj-y				:= entry_$(BITS).o thunk_$(BITS).o syscall_$(BITS).o

obj-y				+= common.o

arch/x86/entry/vdso/Makefile

+4 −2
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 
KBUILD_CFLAGS += $(DISABLE_LTO)

KASAN_SANITIZE			:= n

UBSAN_SANITIZE			:= n

OBJECT_FILES_NON_STANDARD	:= y



VDSO64-$(CONFIG_X86_64)		:= y

VDSOX32-$(CONFIG_X86_X32_ABI)	:= y
@@ -16,6 +17,7 @@ vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o 


# files to link into kernel

obj-y				+= vma.o

OBJECT_FILES_NON_STANDARD_vma.o	:= n



# vDSO images to build

vdso_img-$(VDSO64-y)		+= 64

arch/x86/kernel/Makefile

+8 −3
Original line number Diff line number Diff line
@@ -20,6 +20,11 @@ KASAN_SANITIZE_head$(BITS).o := n 
KASAN_SANITIZE_dumpstack.o				:= n

KASAN_SANITIZE_dumpstack_$(BITS).o			:= n



OBJECT_FILES_NON_STANDARD_head_$(BITS).o		:= y

OBJECT_FILES_NON_STANDARD_relocate_kernel_$(BITS).o	:= y

OBJECT_FILES_NON_STANDARD_mcount_$(BITS).o		:= y

OBJECT_FILES_NON_STANDARD_test_nx.o			:= y



CFLAGS_irq.o := -I$(src)/../include/asm/trace



obj-y			:= process_$(BITS).o signal.o

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