Re: [RFC][PATCH -mm 4/4] Hibernation: Pass CR3 value in hibernation header on x86_64

[Pavel Machek <pavel@ucw.cz>]

Hi!

> From: Rafael J. Wysocki <rjw@sisk.pl>
> 
> Since we already pass the address of restore_registers() in the image header,
> we can also pass the value of the CR3 register from before the hibernation in
> the same way.  This will allow us to avoid using init_level4_pgt page tables
> during the restore.
> 
> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

> @@ -283,7 +290,8 @@ int arch_hibernation_header_save(void *a
>  	if (max_size < sizeof(struct restore_data_record))
>  		return -EOVERFLOW;
>  	rdr->jump_address = restore_jump_address;
> -	rdr->control = (restore_jump_address ^ RESTORE_MAGIC);
> +	rdr->cr3 = restore_cr3;
> +	rdr->control = (restore_jump_address ^ (restore_cr3 ^ RESTORE_MAGIC));
>  	return 0;

Does control want to be renamed as "crc"? Or perphaps we want to just
store MAGIC there, w/o any obfuscation, since obfuscation does not
really buy us anything?

									Pavel
-- 
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