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From: Peter Zijlstra <peterz@infradead.org>
To: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
	Ingo Molnar <mingo@kernel.org>, Juergen Gross <jgross@suse.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>
Subject: Re: [PATCH] objtool: Fix SYSCALL instruction handling and INSN_CONTEXT_SWITCH
Date: Fri, 4 Apr 2025 12:49:38 +0200	[thread overview]
Message-ID: <20250404104938.GO25239@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <41761c1db9acfc34d4f71d44284aa23b3f020f74.1743706046.git.jpoimboe@kernel.org>

On Thu, Apr 03, 2025 at 11:48:13AM -0700, Josh Poimboeuf wrote:

> The real problem here is that INSN_CONTEXT_SWITCH is ambiguous.  It can
> represent both call semantics (SYSCALL, SYSENTER) and return semantics
> (SYSRET, IRET, RETS, RETU).  Those differ significantly: calls preserve
> control flow whereas returns terminate it.

Does that not rather suggest we should perhaps have INSN_SYSCALL /
INSN_SYSRET to replace the single ambiguous thing?



  parent reply	other threads:[~2025-04-04 10:49 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-04-03 18:48 [PATCH] objtool: Fix SYSCALL instruction handling and INSN_CONTEXT_SWITCH Josh Poimboeuf
2025-04-03 18:57 ` Andrew Cooper
2025-04-03 19:05   ` Josh Poimboeuf
2025-04-03 19:15     ` Andrew Cooper
2025-04-03 19:20       ` Josh Poimboeuf
2025-04-04  7:40 ` Jürgen Groß
2025-04-04 10:49 ` Peter Zijlstra [this message]
2025-04-04 14:46   ` Josh Poimboeuf
2025-04-04 14:54     ` Peter Zijlstra
2025-04-04 15:02       ` Josh Poimboeuf
2025-04-04 15:03     ` Juergen Gross

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