linux-kernel - Re: [PATCH v2 09/16] PM / hibernate: Reserve hibernation key and erase footprints

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Date:	Thu, 13 Aug 2015 22:33:37 +0800
From:	joeyli <jlee@...e.com>
To:	"Lee, Chun-Yi" <joeyli.kernel@...il.com>,
	linux-kernel@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, linux-efi@...r.kernel.org,
	linux-pm@...r.kernel.org, "Rafael J. Wysocki" <rjw@...ysocki.net>,
	Matthew Garrett <matthew.garrett@...ula.com>,
	Len Brown <len.brown@...el.com>, Pavel Machek <pavel@....cz>,
	Josh Boyer <jwboyer@...hat.com>,
	Vojtech Pavlik <vojtech@...e.cz>,
	Matt Fleming <matt.fleming@...el.com>,
	Jiri Kosina <jkosina@...e.cz>,
	"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...hat.com>
Subject: Re: [PATCH v2 09/16] PM / hibernate: Reserve hibernation key and
 erase footprints

On Tue, Aug 11, 2015 at 02:16:29PM +0800, Lee, Chun-Yi wrote:
> Add handler to parse the setup data that carrying hibernation key, it
> reserves hibernation key by memblock then copies key to a allocated page
> in later initcall stage.
>
[...snip] 
> diff --git a/arch/x86/power/hibernate_keys.c b/arch/x86/power/hibernate_keys.c
> new file mode 100644
> index 0000000..357dc0e
> --- /dev/null
> +++ b/arch/x86/power/hibernate_keys.c
> @@ -0,0 +1,78 @@
> +/* Hibernation keys handler
> + *
[...snip]
> +static int __init init_hibernation_keys(void)
> +{
> +	struct hibernation_keys *keys;
> +	int ret = 0;
> +
> +	if (!keys_phys_addr)
> +		return -ENODEV;
> +
> +	keys = early_memremap(keys_phys_addr, sizeof(struct hibernation_keys));
> +
> +	/* Copy hibernation keys to a allocated page */
> +	hibernation_keys = (struct hibernation_keys *)get_zeroed_page(GFP_KERNEL);
> +	if (hibernation_keys) {
> +		*hibernation_keys = *keys;
> +	} else {
> +		pr_err("PM: Allocate hibernation keys page failed\n");
> +		ret = -ENOMEM;
> +	}
> +
> +	/* Erase keys data no matter copy success or failed */
> +	memset(keys, 0, sizeof(struct hibernation_keys));
> +	early_memunmap(keys, sizeof(struct hibernation_keys));
> +	memblock_free(keys_phys_addr, sizeof(struct hibernation_keys));
> +	keys_phys_addr = 0;
> +
> +	return ret;
> +}
> +
> +late_initcall(init_hibernation_keys);

Yu's reviewing triggered me rethinking...

I afraid that's too late in late_initcall stage for copying key data that
reserved by memblock. I will try to move this copy action to setup_arch().


Regards
Joey Lee
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