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From: Peter Zijlstra <peterz@infradead.org>
To: Sathvika Vasireddy <sv@linux.ibm.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>,
	christophe.leroy@csgroup.eu, npiggin@gmail.com,
	maddy@linux.ibm.com, linux-kernel@vger.kernel.org,
	linuxppc-dev@lists.ozlabs.org, llvm@lists.linux.dev
Subject: Re: [RFC PATCH] objtool: Skip unannotated intra-function call warning for bl+mflr pattern
Date: Mon, 24 Feb 2025 13:35:34 +0100	[thread overview]
Message-ID: <20250224123534.GB17456@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <4bea75bc-d3f6-4972-b644-f9b5a4e8bb77@linux.ibm.com>

On Fri, Feb 21, 2025 at 02:20:41PM +0530, Sathvika Vasireddy wrote:

> Also, just out of curiosity, how does x86 do it? Does it not use a branch to
> next instruction approach?

x86_64 can use LEA like:

  #define _THIS_IP_ ({ unsigned long __here; asm ("lea 0(%%rip), %0" : "=r" (__here)); __here; })

32bit needs to call a function, read the stack value and return.


  parent reply	other threads:[~2025-02-24 12:35 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-02-19 16:20 [RFC PATCH] objtool: Skip unannotated intra-function call warning for bl+mflr pattern Sathvika Vasireddy
2025-02-20 19:59 ` Josh Poimboeuf
2025-02-21  8:50   ` Sathvika Vasireddy
2025-02-24 10:36     ` Christophe Leroy
2025-02-24 12:35     ` Peter Zijlstra [this message]
2025-02-24 16:25     ` Peter Zijlstra
2025-02-24 17:54       ` Christophe Leroy
2025-02-24  7:15 ` Christophe Leroy
2025-02-24 10:33   ` Christophe Leroy
2025-02-24 13:19     ` Christophe Leroy
2025-02-24 17:09       ` Nathan Chancellor
2025-02-25  7:35         ` Christophe Leroy

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