linux/tools/objtool
Guilherme G. Piccoli 611d4c716d x86/hyperv: Mark hv_ghcb_terminate() as noreturn
Annotate the function prototype and definition as noreturn to prevent
objtool warnings like:

vmlinux.o: warning: objtool: hyperv_init+0x55c: unreachable instruction

Also, as per Josh's suggestion, add it to the global_noreturns list.
As a comparison, an objdump output without the annotation:

[...]
1b63:  mov    $0x1,%esi
1b68:  xor    %edi,%edi
1b6a:  callq  ffffffff8102f680 <hv_ghcb_terminate>
1b6f:  jmpq   ffffffff82f217ec <hyperv_init+0x9c> # unreachable
1b74:  cmpq   $0xffffffffffffffff,-0x702a24(%rip)
[...]

Now, after adding the __noreturn to the function prototype:

[...]
17df:  callq  ffffffff8102f6d0 <hv_ghcb_negotiate_protocol>
17e4:  test   %al,%al
17e6:  je     ffffffff82f21bb9 <hyperv_init+0x469>
[...]  <many insns>
1bb9:  mov    $0x1,%esi
1bbe:  xor    %edi,%edi
1bc0:  callq  ffffffff8102f680 <hv_ghcb_terminate>
1bc5:  nopw   %cs:0x0(%rax,%rax,1) # end of function

Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/32453a703dfcf0d007b473c9acbf70718222b74b.1681342859.git.jpoimboe@kernel.org
2023-04-14 17:31:28 +02:00
..
arch objtool: Make instruction::stack_ops a single-linked list 2023-02-23 09:20:59 +01:00
Documentation objtool: Check that module init/exit function is an indirect call target 2023-01-21 10:50:18 +01:00
include/objtool objtool: Add symbol iteration helpers 2023-04-14 16:08:29 +02:00
.gitignore objtool: Install libsubcmd in build 2023-01-30 16:27:46 -08:00
Build objtool: Install libsubcmd in build 2023-01-30 16:27:46 -08:00
builtin-check.c objtool: Make struct check_options static 2023-02-01 09:15:23 -08:00
check.c x86/hyperv: Mark hv_ghcb_terminate() as noreturn 2023-04-14 17:31:28 +02:00
elf.c objtool: Add symbol iteration helpers 2023-04-14 16:08:29 +02:00
Makefile objtool: Fix HOSTCC flag usage 2023-02-01 09:15:18 -08:00
objtool.c objtool: Remove instruction::list 2023-02-23 09:21:44 +01:00
orc_dump.c x86,objtool: Split UNWIND_HINT_EMPTY in two 2023-03-23 23:18:58 +01:00
orc_gen.c objtool: Add WARN_INSN() 2023-04-14 16:08:28 +02:00
special.c objtool: Make struct entries[] static and const 2023-02-01 09:15:22 -08:00
sync-check.sh objtool: Add objtool_types.h 2023-03-23 23:18:56 +01:00
weak.c objtool: Ditch subcommands 2022-04-22 12:32:01 +02:00