linux-kernel - Re: [PATCH] livepatch: add (un)patch hooks

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Message-ID: <20170720042000.34trkuzwevrkscds@treble>
Date:   Wed, 19 Jul 2017 23:20:00 -0500
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     Petr Mladek <pmladek@...e.com>
Cc:     Joe Lawrence <joe.lawrence@...hat.com>,
        live-patching@...r.kernel.org, linux-kernel@...r.kernel.org,
        Jessica Yu <jeyu@...nel.org>, Jiri Kosina <jikos@...nel.org>,
        Miroslav Benes <mbenes@...e.cz>,
        Chris J Arges <chris.j.arges@...onical.com>
Subject: Re: [PATCH] livepatch: add (un)patch hooks

On Wed, Jul 19, 2017 at 11:17:23PM -0500, Josh Poimboeuf wrote:
> +static void swapgs_unload_hook(void)
> +{
> +	if (paravirt_enabled() && strcmp(pv_info.name, "KVM"))
> +		return;
> +
> +	write_cr0(read_cr0() & ~X86_CR0_WP);
> +	barrier();
> +
> +	set_intr_gate_ist(X86_TRAP_SS, stack_segment_v2, STACKFAULT_STACK);

s/stack_segment_v2/stack_segment/ for the unload hook

> +
> +	barrier();
> +	write_cr0(read_cr0() | X86_CR0_WP);
> +}
> +KLP_UNLOAD_HOOK(swapgs_unload_hook);

-- 
Josh