b746046238
Teach objtool a little more about IRET so that we can avoid using the SAVE/RESTORE annotation. In particular, make the weird corner case in insn->restore go away. The purpose of that corner case is to deal with the fact that UNWIND_HINT_RESTORE lands on the instruction after IRET, but that instruction can end up being outside the basic block, consider: if (cond) sync_core() foo(); Then the hint will land on foo(), and we'll encounter the restore hint without ever having seen the save hint. By teaching objtool about the arch specific exception frame size, and assuming that any IRET in an STT_FUNC symbol is an exception frame sized POP, we can remove the use of save/restore hints for this code. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20200416115118.631224674@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
---|---|---|
.. | ||
arch/x86 | ||
Documentation | ||
.gitignore | ||
arch.h | ||
Build | ||
builtin-check.c | ||
builtin-orc.c | ||
builtin.h | ||
cfi.h | ||
check.c | ||
check.h | ||
elf.c | ||
elf.h | ||
Makefile | ||
objtool.c | ||
orc_dump.c | ||
orc_gen.c | ||
orc.h | ||
special.c | ||
special.h | ||
sync-check.sh | ||
warn.h |