linux/tools/objtool
Peter Zijlstra b746046238 objtool: Better handle IRET
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>
2020-04-22 10:53:50 +02:00
..
arch/x86 objtool: Better handle IRET 2020-04-22 10:53:50 +02:00
Documentation objtool: Documentation: document UACCESS warnings 2020-04-22 10:53:49 +02:00
.gitignore .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
arch.h objtool: Better handle IRET 2020-04-22 10:53:50 +02:00
Build objtool: Optimize find_symbol_*() and read_symbols() 2020-03-25 18:28:29 +01:00
builtin-check.c objtool: Add a statistics mode 2020-03-25 18:28:28 +01:00
builtin-orc.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 13 2019-05-21 11:28:45 +02:00
builtin.h objtool: Add a statistics mode 2020-03-25 18:28:28 +01:00
cfi.h objtool: Split out arch-specific CFI definitions 2020-04-22 10:53:49 +02:00
check.c objtool: Better handle IRET 2020-04-22 10:53:50 +02:00
check.h objtool: Support multiple stack_op per instruction 2020-04-22 10:53:50 +02:00
elf.c objtool: Fix off-by-one in symbol_by_offset() 2020-04-22 10:53:49 +02:00
elf.h objtool: Fix 32bit cross builds 2020-04-22 10:53:49 +02:00
Makefile objtool: Split out arch-specific CFI definitions 2020-04-22 10:53:49 +02:00
objtool.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 13 2019-05-21 11:28:45 +02:00
orc_dump.c objtool: Support Clang non-section symbols in ORC dump 2020-04-14 11:59:52 +02:00
orc_gen.c objtool: Support Clang non-section symbols in ORC generation 2020-04-14 12:03:42 +02:00
orc.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 13 2019-05-21 11:28:45 +02:00
special.c objtool: Optimize read_sections() 2020-03-25 18:28:30 +01:00
special.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 13 2019-05-21 11:28:45 +02:00
sync-check.sh objtool: Silence build output 2020-01-22 07:54:34 +01:00
warn.h objtool: Rename find_containing_func() 2020-03-25 18:28:29 +01:00