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Date:   Thu, 1 Jun 2023 13:52:16 -0400
From:   Kent Overstreet <kent.overstreet@linux.dev>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Mike Rapoport <rppt@kernel.org>, linux-kernel@vger.kernel.org,
        Andrew Morton <akpm@linux-foundation.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Christophe Leroy <christophe.leroy@csgroup.eu>,
        "David S. Miller" <davem@davemloft.net>,
        Dinh Nguyen <dinguyen@kernel.org>,
        Heiko Carstens <hca@linux.ibm.com>,
        Helge Deller <deller@gmx.de>,
        Huacai Chen <chenhuacai@kernel.org>,
        Luis Chamberlain <mcgrof@kernel.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Russell King <linux@armlinux.org.uk>,
        Song Liu <song@kernel.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        Thomas Gleixner <tglx@linutronix.de>,
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Subject: Re: [PATCH 12/13] x86/jitalloc: prepare to allocate exectuatble
 memory as ROX
Message-ID: <ZHja0HOUabUxD5YS@moria.home.lan>
References: <20230601101257.530867-1-rppt@kernel.org>
 <20230601101257.530867-13-rppt@kernel.org>
 <20230601103050.GT4253@hirez.programming.kicks-ass.net>
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On Thu, Jun 01, 2023 at 12:30:50PM +0200, Peter Zijlstra wrote:
> On Thu, Jun 01, 2023 at 01:12:56PM +0300, Mike Rapoport wrote:
> 
> > +static void __init_or_module do_text_poke(void *addr, const void *opcode, size_t len)
> > +{
> > +	if (system_state < SYSTEM_RUNNING) {
> > +		text_poke_early(addr, opcode, len);
> > +	} else {
> > +		mutex_lock(&text_mutex);
> > +		text_poke(addr, opcode, len);
> > +		mutex_unlock(&text_mutex);
> > +	}
> > +}
> 
> So I don't much like do_text_poke(); why?

Could you share why?

I think the impementation sucks but conceptually it's the right idea -
create a new temporary mapping to avoid the need for RWX mappings.