Objtool is throwing unannotated intra-function call warnings
when run on vmlinux with --ftr-fixup option.
One such example:
vmlinux: warning: objtool: .text+0x3d94:
unannotated intra-function call
.text + 0x3d94 = c000000000008000 + 3d94 = c0000000000081d4
c0000000000081d4: 45 24 02 48 bl c00000000002a618
<system_reset_exception+0x8>
c00000000002a610 <system_reset_exception>:
c00000000002a610: 0e 01 4c 3c addis r2,r12,270
c00000000002a610: R_PPC64_REL16_HA .TOC.
c00000000002a614: f0 6c 42 38 addi r2,r2,27888
c00000000002a614: R_PPC64_REL16_LO .TOC.+0x4
c00000000002a618: a6 02 08 7c mflr r0
This is happening because we should be looking for destination
symbols that are at absolute offsets instead of relative offsets.
After fixing dest_off to point to absolute offset, there are still
a lot of these warnings shown.
In the above example, objtool is computing the destination
offset to be c00000000002a618, which points to a completely
different instruction. find_call_destination() is looking for this
offset and failing. Instead, we should be looking for destination
offset c00000000002a610 which points to system_reset_exception
function.
Even after fixing the way destination offset is computed, and
after looking for dest_off - 0x8 in cases where the original offset
is not found, there are still a lot of unannotated intra-function
call warnings generated. This is due to symbols that are not
properly annotated.
So, for now, as a hack to curb these warnings, do not emit
unannotated intra-function call warnings when objtool is run
with --ftr-fixup option.
Skip add_jump_destinations() and suppress intra-function call
errors in --ftr-fixup mode. The feature fixup pass only needs fixup
entry tables, relocation entries from .__ftr_alternates.text, and
elf_write_insn() to patch branch offsets.
Signed-off-by: Sathvika Vasireddy <[email protected]>
---
tools/objtool/check.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 92fe5dc05cdb..9c6b892792a4 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1598,7 +1598,6 @@ static int add_jump_destinations(struct objtool_file
*file)
dest_off == func->offset + func->len)
continue;
-
ERROR_INSN(insn, "can't find jump dest instruction at
%s",
offstr(dest_sec, dest_off));
return -1;
@@ -1680,7 +1679,7 @@ static int add_call_destinations(struct objtool_file
*file)
if (func && func->ignore)
continue;
- if (!insn_call_dest(insn)) {
+ if (!insn_call_dest(insn) && !opts.ftr_fixup) {
ERROR_INSN(insn, "unannotated intra-function
call");
return -1;
}
@@ -2636,8 +2635,10 @@ static int decode_sections(struct objtool_file *file)
return -1;
}
- if (add_jump_destinations(file))
- return -1;
+ if (!opts.ftr_fixup) {
+ if (add_jump_destinations(file))
+ return -1;
+ }
/*
* Must be before add_call_destination(); it changes INSN_CALL to
--
2.43.0
