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Sender: Ingo Molnar <mingo.kernel.org@gmail.com>
Date:   Thu, 14 Sep 2023 16:16:47 +0200
From:   Ingo Molnar <mingo@kernel.org>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     "Huang, Kai" <kai.huang@intel.com>, lkp <lkp@intel.com>,
        "kirill.shutemov@linux.intel.com" <kirill.shutemov@linux.intel.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "oe-kbuild-all@lists.linux.dev" <oe-kbuild-all@lists.linux.dev>,
        "x86@kernel.org" <x86@kernel.org>,
        "dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>
Subject: Re: [tip:x86/tdx 8/12] vmlinux.o: warning: objtool:
 __tdx_hypercall+0x128: __tdx_hypercall_failed() is missing a __noreturn
 annotation
Message-ID: <ZQMVz/wepyo9rlhE@gmail.com>
References: <202309140828.9RdmlH2Z-lkp@intel.com>
 <90f0a4d44704f9c296f3a4d8b72c57f2916aa09d.camel@intel.com>
 <377b1ce2ecd390f4b6f8cdf68d22c708f7cef6d1.camel@intel.com>
 <20230914072959.GC16631@noisy.programming.kicks-ass.net>
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* Peter Zijlstra <peterz@infradead.org> wrote:

> > It appears the __noreturn must be annotated to the function declaration 
> > but not the function body.  I'll send out the fix as soon as I confirm 
> > the fix with LKP.
> 
> FWIW, the reason being that...
> 
> The point of noreturn is that the caller should know to stop generating 
> code. For that the declaration needs the attribute, because call sites 
> typically do not have access to the function definition in C.

BTW., arguably shouldn't the compiler generate a warning to begin with, 
when it encounters a noreturn function definition whose prototype doesn't 
have the attribute?

Thanks,

	Ingo