x86/entry: Move thunk restore code into thunk functions
Commit Message
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: fedb724c3db5 ("objtool: Detect missing __noreturn annotations")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202305281037.3PaI3tW4-lkp@intel.com/
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
arch/x86/entry/thunk_64.S | 20 ++++++++------------
1 file changed, 8 insertions(+), 12 deletions(-)
@@ -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)