On Fri, Mar 03, 2017 at 09:11:52PM +0800, Baoquan He wrote:
> And another meaning of defining kernel iamge size and mapping size
> differently is we can randomize the limited kernel image in the mapping
> area. If they are the same or kernel image can be very large, the
> position will be fixed or very few, kernel text KASLR will be
> meaningless.
This is simply not true:
@@ -408,9 +408,9 @@ static unsigned long find_random_virt_addr(unsigned long
minimum,
/*
* There are how many CONFIG_PHYSICAL_ALIGN-sized slots
* that can hold image_size within the range of minimum to
- * KERNEL_IMAGE_SIZE?
+ * KERNEL_MAPPING_SIZE?
*/
- slots = (KERNEL_IMAGE_SIZE - minimum - image_size) /
+ slots = (KERNEL_MAPPING_SIZE - minimum - image_size) /
CONFIG_PHYSICAL_ALIGN + 1;
*With* kaslr, KERNEL_IMAGE_SIZE = 1G and KERNEL_MAPPING_SIZE = 1G.
Before your patch KERNEL_IMAGE_SIZE = 1G too with kaslr enabled.
--
Regards/Gruss,
Boris.
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284
(AG Nürnberg)
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