From: Sathvika Vasireddy <sv@linux•ibm.com>
To: nathan@kernel•org, nsc@kernel•org, maddy@linux•ibm.com,
mpe@ellerman•id.au, npiggin@gmail•com, chleroy@kernel•org,
jpoimboe@kernel•org, peterz@infradead•org, ojeda@kernel•org,
masahiroy@kernel•org, lossin@kernel•org, tamird@kernel•org,
thomas.weissschuh@linutronix•de, rostedt@goodmis•org,
ihor.solodrai@linux•dev, thuth@redhat•com, pmladek@suse•com,
aliceryhl@google•com, elver@google•com, kees@kernel•org,
legion@kernel•org, ardb@kernel•org, yuxuan.zuo@outlook•com,
alexghiti@rivosinc•com, alexandre.chartre@oracle•com,
bp@alien8•de, linux-kbuild@vger•kernel.org,
linux-kernel@vger•kernel.org, linuxppc-dev@lists•ozlabs.org,
sv@linux•ibm.com
Subject: [PATCH v1 4/6] objtool/powerpc: Skip jump destination analysis and unnanotated intra-function call warnings for --ftr-fixup
Date: Tue, 5 May 2026 14:16:26 +0530 [thread overview]
Message-ID: <20260505084628.17940-5-sv@linux.ibm.com> (raw)
In-Reply-To: <20260505084628.17940-1-sv@linux.ibm.com>
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 <sv@linux•ibm.com>
---
tools/objtool/check.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index f3501b149829..14644ca36d73 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1644,7 +1644,6 @@ 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;
@@ -1727,8 +1726,11 @@ static int add_call_destinations(struct objtool_file *file)
continue;
if (!insn_call_dest(insn)) {
- ERROR_INSN(insn, "unannotated intra-function call");
- return -1;
+ if (!opts.ftr_fixup) {
+ ERROR_INSN(insn, "unannotated intra-function call");
+ return -1;
+ }
+ continue;
}
if (func && !is_func_sym(insn_call_dest(insn))) {
@@ -2681,8 +2683,10 @@ 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
next prev parent reply other threads:[~2026-05-05 8:48 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-05 8:46 [PATCH v1 0/6] objtool: Fixup alternate feature relative addresses Sathvika Vasireddy
2026-05-05 8:46 ` [PATCH v1 1/6] objtool/powerpc: Add build-time fixup of alternate feature branch targets Sathvika Vasireddy
2026-05-05 14:45 ` Peter Zijlstra
2026-05-05 14:49 ` Peter Zijlstra
2026-05-05 15:48 ` Christophe Leroy (CS GROUP)
2026-05-06 7:17 ` Peter Zijlstra
2026-05-06 14:28 ` Segher Boessenkool
2026-05-05 15:56 ` Segher Boessenkool
2026-05-06 7:00 ` Peter Zijlstra
2026-05-06 13:58 ` Segher Boessenkool
2026-05-06 14:22 ` Peter Zijlstra
2026-05-06 14:42 ` Segher Boessenkool
2026-05-05 8:46 ` [PATCH v1 2/6] objtool: Set ELF_F_LAYOUT flag to preserve vmlinux segment layout Sathvika Vasireddy
2026-05-05 8:46 ` [PATCH v1 3/6] objtool: Fix "can't find starting instruction" warnings on vmlinux Sathvika Vasireddy
2026-05-05 8:46 ` Sathvika Vasireddy [this message]
2026-05-05 8:46 ` [PATCH v1 5/6] kbuild: Add objtool integration for PowerPC feature fixups Sathvika Vasireddy
2026-05-05 8:46 ` [PATCH v1 6/6] powerpc: Enable build-time feature fixup processing by default Sathvika Vasireddy
2026-05-05 9:05 ` [PATCH v1 0/6] objtool: Fixup alternate feature relative addresses Christophe Leroy (CS GROUP)
2026-05-05 11:40 ` Peter Zijlstra
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