Re: [PATCH v2 9/9] change the relocations behavior for kaslr on x86_64

From: Yinghai Lu <yinghai@kernel.org>
To: Baoquan He <bhe@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
	Kees Cook <keescook@chromium.org>,
	Vivek Goyal <vgoyal@redhat.com>,
	Andy Lutomirski <luto@amacapital.net>,
	Andrew Morton <akpm@linux-foundation.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 9/9] change the relocations behavior for kaslr on x86_64
Date: Wed, 4 Mar 2015 15:16:53 -0800	[thread overview]
Message-ID: <CAE9FiQVw9-75hG4+QYdGON0zf5Hv2ZPPno_mzRywuCWvCmGZpA@mail.gmail.com> (raw)
In-Reply-To: <1425308310-2318-10-git-send-email-bhe@redhat.com>

On Mon, Mar 2, 2015 at 6:58 AM, Baoquan He <bhe@redhat.com> wrote:

> @@ -455,17 +455,16 @@ unsigned char *choose_kernel_location(struct boot_params *params,
>                        output_size);

you forgot to change

        /* Record the various known unsafe memory ranges. */
        mem_avoid_init((unsigned long)input, input_size,
                       (unsigned long)output, init_size);

to

        /* Record the various known unsafe memory ranges. */
        mem_avoid_init((unsigned long)input, input_size,
                       (unsigned long)*output, init_size);

>
>         /* Walk e820 and find a random address. */
> -       random = find_random_addr(choice, output_size);
> -       if (!random) {
> +       random = find_random_phy_addr((unsigned long)*output, output_size);
> +       if (!random)
>                 debug_putstr("KASLR could not find suitable E820 region...\n");
> -               goto out;
> -       }
> +       else
> +               *output = (unsigned char*)random;