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From: Shivang Upadhyay <shivangu@linux.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
	linuxppc-dev@lists.ozlabs.org, 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, pmladek@suse.com,
	rostedt@goodmis.org, tamird@kernel.org,
	thomas.weissschuh@linutronix.de, thuth@redhat.com,
	yuxuan.zuo@outlook.com, sourabhjain@linux.ibm.com
Subject: Re: [PATCH v2 4/6] objtool/powerpc: Skip jump destination analysis and unnanotated intra-function call warnings for --ftr-fixup
Date: Wed, 30 Sep 2026 11:43:10 +0530	[thread overview]
Message-ID: <05e06ab0d9fc8810fc50e888e9e0f55b2ec9b77f.camel@linux.ibm.com> (raw)
In-Reply-To: <20260929142559.GC88198@noisy.programming.kicks-ass.net>

On Tue, 2026-09-29 at 16:25 +0200, Peter Zijlstra wrote:
> > 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.
> 
> Again, confused. We run objtool on objects, this is pre-linking,
> there
> are no absolute offsets.
Hi Peter,

This is the special requirement of patching jump assembly instructions
that we need to know where the jump is performed from/to. As per 5/6
objtool is run post link on vmlinux. If handling post-link information
is outside the scope of objtool, please let me know.

Regards,
~Shivang.

  reply	other threads:[~2026-09-30  6:12 UTC|newest]

Thread overview: 13+ 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
2026-09-30  9:48   ` Peter Zijlstra
2026-09-29  5:51 ` [PATCH v2 3/6] objtool: Fix "can't find starting instruction" warnings on vmlinux Shivang Upadhyay
2026-09-29 14:12   ` Peter Zijlstra
2026-09-29 14:24   ` Peter Zijlstra
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 14:25   ` Peter Zijlstra
2026-09-30  6:13     ` Shivang Upadhyay [this message]
2026-09-30  9:44       ` Peter Zijlstra
2026-09-29  5:51 ` [PATCH v2 5/6] kbuild: Add objtool integration for PowerPC feature fixups Shivang Upadhyay
2026-09-29  5:51 ` [PATCH v2 6/6] powerpc: Enable build-time feature fixup processing by default Shivang Upadhyay

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