linux-stable.git/tools/objtool/orc_gen.c, branch v6.4

objtool: Add WARN_INSN()

2023-04-14T14:08:28+00:00

It's easier to use and also gives easy access to the instruction's
containing function, which is useful for printing that function's
symbol.  It will also be useful in the future for rate-limiting and
disassembly of warned functions.

Signed-off-by: Josh Poimboeuf 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://lkml.kernel.org/r/2eaa3155c90fba683d8723599f279c46025b75f3.1681325924.git.jpoimboe@kernel.org

x86,objtool: Split UNWIND_HINT_EMPTY in two

2023-03-23T22:18:58+00:00

Mark reported that the ORC unwinder incorrectly marks an unwind as
reliable when the unwind terminates prematurely in the dark corners of
return_to_handler() due to lack of information about the next frame.

The problem is UNWIND_HINT_EMPTY is used in two different situations:

  1) The end of the kernel stack unwind before hitting user entry, boot
     code, or fork entry

  2) A blind spot in ORC coverage where the unwinder has to bail due to
     lack of information about the next frame

The ORC unwinder has no way to tell the difference between the two.
When it encounters an undefined stack state with 'end=1', it blindly
marks the stack reliable, which can break the livepatch consistency
model.

Fix it by splitting UNWIND_HINT_EMPTY into UNWIND_HINT_UNDEFINED and
UNWIND_HINT_END_OF_STACK.

Reported-by: Mark Rutland 
Signed-off-by: Josh Poimboeuf 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Steven Rostedt (Google) 
Acked-by: Peter Zijlstra (Intel) 
Link: https://lore.kernel.org/r/fd6212c8b450d3564b855e1cb48404d6277b4d9f.1677683419.git.jpoimboe@kernel.org

x86,objtool: Introduce ORC_TYPE_*

2023-03-23T22:18:57+00:00

Unwind hints and ORC entry types are two distinct things.  Separate them
out more explicitly.

Signed-off-by: Josh Poimboeuf 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Peter Zijlstra (Intel) 
Link: https://lore.kernel.org/r/cc879d38fff8a43f8f7beb2fd56e35a5a384d7cd.1677683419.git.jpoimboe@kernel.org

objtool: Add objtool_types.h

2023-03-23T22:18:56+00:00

Reduce the amount of header sync churn by splitting the shared objtool.h
types into a new file.

Signed-off-by: Josh Poimboeuf 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Peter Zijlstra (Intel) 
Link: https://lore.kernel.org/r/dec622720851210ceafa12d4f4c5f9e73c832152.1677683419.git.jpoimboe@kernel.org

objtool: Fix ORC 'signal' propagation

2023-02-23T08:21:50+00:00

There have been some recently reported ORC unwinder warnings like:

  WARNING: can't access registers at entry_SYSCALL_64_after_hwframe+0x63/0xcd
  WARNING: stack going in the wrong direction? at __sys_setsockopt+0x2c6/0x5b0 net/socket.c:2271

And a KASAN warning:

  BUG: KASAN: stack-out-of-bounds in unwind_next_frame (arch/x86/include/asm/ptrace.h:136 arch/x86/kernel/unwind_orc.c:455)

It turns out the 'signal' bit isn't getting propagated from the unwind
hints to the ORC entries, making the unwinder confused at times.

Fixes: ffb1b4a41016 ("x86/unwind/orc: Add 'signal' field to ORC metadata")
Reported-by: kernel test robot 
Reported-by: Dmitry Vyukov 
Signed-off-by: Josh Poimboeuf 
Signed-off-by: Ingo Molnar 
Link: https://lore.kernel.org/r/97eef9db60cd86d376a9a40d49d77bb67a8f6526.1676579666.git.jpoimboe@kernel.org

objtool: Use target file endianness instead of a compiled constant

2022-11-18T08:00:15+00:00

Some architectures like powerpc support both endianness, it's
therefore not possible to fix the endianness via arch/endianness.h
because there is no easy way to get the target endianness at
build time.

Use the endianness recorded in the file objtool is working on.

Tested-by: Naveen N. Rao 
Reviewed-by: Naveen N. Rao 
Acked-by: Josh Poimboeuf 
Acked-by: Peter Zijlstra (Intel) 
Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20221114175754.1131267-10-sv@linux.ibm.com

Merge branch 'objtool/urgent'

2021-10-06T22:40:17+00:00

Fixup conflicts.

# Conflicts:
#	tools/objtool/check.c

objtool: Remove redundant 'len' field from struct section

2021-10-05T19:03:21+00:00

The section structure already contains sh_size, so just remove the extra
'len' member that requires extra mirroring and potential confusion.

Suggested-by: Josh Poimboeuf 
Signed-off-by: Joe Lawrence 
Reviewed-by: Miroslav Benes 
Signed-off-by: Josh Poimboeuf 
Link: https://lore.kernel.org/r/20210822225037.54620-3-joe.lawrence@redhat.com
Cc: Andy Lavr 
Cc: Peter Zijlstra 
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org

objtool: Introduce CFI hash

2021-09-15T13:51:45+00:00

Andi reported that objtool on vmlinux.o consumes more memory than his
system has, leading to horrific performance.

This is in part because we keep a struct instruction for every
instruction in the file in-memory. Shrink struct instruction by
removing the CFI state (which includes full register state) from it
and demand allocating it.

Given most instructions don't actually change CFI state, there's lots
of repetition there, so add a hash table to find previous CFI
instances.

Reduces memory consumption (and runtime) for processing an
x86_64-allyesconfig:

  pre:  4:40.84 real,   143.99 user,    44.18 sys,      30624988 mem
  post: 2:14.61 real,   108.58 user,    25.04 sys,      16396184 mem

Suggested-by: Andi Kleen 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://lore.kernel.org/r/20210624095147.756759107@infradead.org

objtool: Create reloc sections implicitly

2021-04-02T10:44:37+00:00

Have elf_add_reloc() create the relocation section implicitly.

Suggested-by: Josh Poimboeuf 
Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Borislav Petkov 
Signed-off-by: Ingo Molnar 
Reviewed-by: Miroslav Benes 
Link: https://lkml.kernel.org/r/20210326151259.880174448@infradead.org