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From: Shivang Upadhyay <shivangu@linux.ibm.com>
To: linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
	linuxppc-dev@lists.ozlabs.org
Cc: sv@linux.ibm.com, alexandre.chartre@oracle.com,
	alexghiti@rivosinc.com, aliceryhl@google.com, ardb@kernel.org,
	bp@alien8.de, chleroy@kernel.org, elver@google.com,
	ihor.solodrai@linux.dev, jpoimboe@kernel.org, kees@kernel.org,
	legion@kernel.org, lossin@kernel.org, maddy@linux.ibm.com,
	masahiroy@kernel.org, mpe@ellerman.id.au, nathan@kernel.org,
	npiggin@gmail.com, nsc@kernel.org, ojeda@kernel.org,
	peterz@infradead.org, pmladek@suse.com, rostedt@goodmis.org,
	tamird@kernel.org, thomas.weissschuh@linutronix.de,
	thuth@redhat.com, yuxuan.zuo@outlook.com,
	sourabhjain@linux.ibm.com,
	Shivang Upadhyay <shivangu@linux.ibm.com>
Subject: [PATCH v2 5/6] kbuild: Add objtool integration for PowerPC feature fixups
Date: Tue, 29 Sep 2026 11:21:36 +0530	[thread overview]
Message-ID: <20260929055138.43489-6-shivangu@linux.ibm.com> (raw)
In-Reply-To: <20260929055138.43489-1-shivangu@linux.ibm.com>

From: Sathvika Vasireddy <sv@linux.ibm.com>

Add build system support for PowerPC feature fixup processing:

- Add HAVE_OBJTOOL_FTR_FIXUP config option for architectures that
support
  build-time feature fixup processing
- Integrate objtool feature fixup processing into vmlinux build

Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sathvika Vasireddy <sv@linux.ibm.com>
Acked-by: Nicolas Schier <nsc@kernel.org>  # kbuild
Signed-off-by: Shivang Upadhyay <shivangu@linux.ibm.com>
---
 Makefile                 | 7 +++++++
 scripts/Makefile.lib     | 4 ++--
 scripts/Makefile.vmlinux | 3 ++-
 3 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/Makefile b/Makefile
index 6b8b812f23b9..363cad32fb26 100644
--- a/Makefile
+++ b/Makefile
@@ -1566,6 +1566,13 @@ ifdef CONFIG_OBJTOOL
 prepare: tools/objtool
 endif
 
+# CONFIG_OBJTOOL and CONFIG_HAVE_OBJTOOL_FTR_FIXUP are unrelated, separate
+# options. It was integrated in objtool in order to borrow the elf parser,
+# but this is different from how the other objtool commands are used.
+ifdef CONFIG_HAVE_OBJTOOL_FTR_FIXUP
+prepare: tools/objtool
+endif
+
 ifdef CONFIG_BPF
 ifdef CONFIG_DEBUG_INFO_BTF
 prepare: tools/bpf/resolve_btfids
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 0a4fdd8bd975..efcedeb207b7 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -182,10 +182,10 @@ cpp_flags      = -Wp,-MMD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE)     \
 
 ld_flags       = $(KBUILD_LDFLAGS) $(ldflags-y) $(LDFLAGS_$(@F))
 
-ifdef CONFIG_OBJTOOL
-
 objtool := $(objtree)/tools/objtool/objtool
 
+ifdef CONFIG_OBJTOOL
+
 objtool-args-$(CONFIG_HAVE_JUMP_LABEL_HACK)		+= --hacks=jump_label
 objtool-args-$(CONFIG_HAVE_NOINSTR_HACK)		+= --hacks=noinstr
 objtool-args-$(CONFIG_MITIGATION_CALL_DEPTH_TRACKING)	+= --hacks=skylake
diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux
index fcae1e432d9a..a1bef0638ecb 100644
--- a/scripts/Makefile.vmlinux
+++ b/scripts/Makefile.vmlinux
@@ -65,7 +65,8 @@ ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)
 # Final link of vmlinux with optional arch pass after final link
 cmd_link_vmlinux =							\
 	$< "$(LD)" "$(KBUILD_LDFLAGS)" "$(LDFLAGS_vmlinux)" "$@";	\
-	$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)
+	$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true);	\
+	$(if $(CONFIG_HAVE_OBJTOOL_FTR_FIXUP), $(objtool) --ftr-fixup --link $@, true)
 
 targets += vmlinux.unstripped .vmlinux.export.o
 vmlinux.unstripped: scripts/link-vmlinux.sh vmlinux.o .vmlinux.export.o $(KBUILD_LDS) FORCE
-- 
2.54.0


  parent reply	other threads:[~2026-09-29  5:53 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-29  5:51 [PATCH v2 0/6] objtool: Fixup alternate feature relative addresses Shivang Upadhyay
2026-09-29  5:51 ` [PATCH v2 1/6] objtool/powerpc: Add build-time fixup of alternate feature branch targets Shivang Upadhyay
2026-09-29  5:51 ` [PATCH v2 2/6] objtool: Set ELF_F_LAYOUT flag to preserve vmlinux segment layout Shivang Upadhyay
2026-09-29  5:51 ` [PATCH v2 3/6] objtool: Fix "can't find starting instruction" warnings on vmlinux Shivang Upadhyay
2026-09-29  5:51 ` [PATCH v2 4/6] objtool/powerpc: Skip jump destination analysis and unnanotated intra-function call warnings for --ftr-fixup Shivang Upadhyay
2026-09-29  5:51 ` Shivang Upadhyay [this message]
2026-09-29  5:51 ` [PATCH v2 6/6] powerpc: Enable build-time feature fixup processing by default Shivang Upadhyay

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