Commit ac27ecf6 authored by Josh Poimboeuf's avatar Josh Poimboeuf
Browse files

x86/entry: Move thunk restore code into thunk functions 



There's no need for both thunk functions to jump to the same shared
thunk restore code which lives outside the thunk function boundaries.
It disrupts i-cache locality and confuses objtool.  Keep it simple by
keeping each thunk's restore code self-contained within the function.

Fixes a bunch of false positive "missing __noreturn" warnings like:

  vmlinux.o: warning: objtool: do_arch_prctl_common+0xf4: preempt_schedule_thunk() is missing a __noreturn annotation

Fixes: fedb724c ("objtool: Detect missing __noreturn annotations")
Reported-by: default avatarkernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202305281037.3PaI3tW4-lkp@intel.com/
Link: https://lore.kernel.org/r/46aa8aeb716f302e22e1673ae15ee6fe050b41f4.1685488050.git.jpoimboe@kernel.org


Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@kernel.org>
parent 02012623

arch/x86/entry/thunk_64.S

+8 −12
Original line number Diff line number Diff line
@@ -26,17 +26,7 @@ SYM_FUNC_START(\name) 
	pushq %r11



	call \func

	jmp  __thunk_restore

SYM_FUNC_END(\name)

	_ASM_NOKPROBE(\name)

	.endm



	THUNK preempt_schedule_thunk, preempt_schedule

	THUNK preempt_schedule_notrace_thunk, preempt_schedule_notrace

	EXPORT_SYMBOL(preempt_schedule_thunk)

	EXPORT_SYMBOL(preempt_schedule_notrace_thunk)



SYM_CODE_START_LOCAL(__thunk_restore)

	popq %r11

	popq %r10

	popq %r9
@@ -48,5 +38,11 @@ SYM_CODE_START_LOCAL(__thunk_restore) 
	popq %rdi

	popq %rbp

	RET

	_ASM_NOKPROBE(__thunk_restore)

SYM_CODE_END(__thunk_restore)
 
SYM_FUNC_END(\name)

	_ASM_NOKPROBE(\name)

	.endm



THUNK preempt_schedule_thunk, preempt_schedule

THUNK preempt_schedule_notrace_thunk, preempt_schedule_notrace

EXPORT_SYMBOL(preempt_schedule_thunk)

EXPORT_SYMBOL(preempt_schedule_notrace_thunk)