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Subject: Re: [PATCH] loongarch: Only select HAVE_OBJTOOL and allow ORC
 unwinder if the inline assembler supports R_LARCH_{32,64}_PCREL
From: Xi Ruoyao <xry111@xry111.site>
To: Huacai Chen <chenhuacai@kernel.org>
Cc: Jinyang He <hejinyang@loongson.cn>, Nathan Chancellor
 <nathan@kernel.org>,  Peter Zijlstra <peterz@infradead.org>, WANG Xuerui
 <kernel@xen0n.name>, Tiezhu Yang <yangtiezhu@loongson.cn>,  Nick
 Desaulniers <ndesaulniers@google.com>, Bill Wendling <morbo@google.com>,
 Justin Stitt <justinstitt@google.com>,  Youling Tang
 <tangyouling@kylinos.cn>, loongarch@lists.linux.dev,
 linux-kernel@vger.kernel.org,  llvm@lists.linux.dev,
 mengqinggang@loongson.cn, cailulu@loongson.cn,  wanglei@loongson.cn,
 luweining@loongson.cn, Yujie Liu <yujie.liu@intel.com>,  Heng Qi
 <hengqi@linux.alibaba.com>, Tejun Heo <tj@kernel.org>
Date: Sat, 15 Jun 2024 18:22:14 +0800
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On Sat, 2024-06-15 at 17:33 +0800, Huacai Chen wrote:
> > To me for now we should just make OBJTOOL and ORC depend on BROKEN and
> > backport to stable...
> But this patch allows clang to build objtool, which seems broken, too.

Yes, so I mean make objtool depend on CONFIG_BROKEN because it is indeed
broken as at now.

Or we'll end up at least:

select HAVE_OBJTOOL if AS_HAS_EXPLICIT_RELOCS && AS_HAS_THIN_ADD_SUB && !CC=
_IS_CLANG && !RUST

this is already nasty and I still don't know if it covers all broken
cases (I've no idea if GCC will generate frame pointer in some cases as
well...)

> > Even if we can fix both the -mno-thin-add-sub problem and the frame
> > pointer problem in these weeks, they'll be some nontrivial large change
> > and improper to backport.=C2=A0 Thus we have to admit objtool doesn't r=
eally
> > work for old releases and mark it broken.
> I don't like to disable objtool, unless there is no better solution.
> And it seems there has already been some "large fix" in objtool's
> history.

Then we can still backport the large fix to the stable branches when we
finish it up.

--=20
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University