Commit b3e0423c authored by Vasily Gorbik's avatar Vasily Gorbik
Browse files

s390/kaslr: randomize amode31 base address 



When the KASLR is enabled, randomize the base address of the amode31 image
within the first 2 GB, similar to the approach taken for the vmlinux
image. This makes it harder to predict the location of amode31 data
and code.

Reviewed-by: default avatarAlexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
parent 6e259bc5

arch/s390/boot/startup.c

+4 −2
Original line number Diff line number Diff line
@@ -278,7 +278,7 @@ void startup_kernel(void) 
{

	unsigned long max_physmem_end;

	unsigned long vmlinux_lma = 0;

	unsigned long amode31_lma;

	unsigned long amode31_lma = 0;

	unsigned long asce_limit;

	unsigned long safe_addr;

	void *img;
@@ -338,7 +338,9 @@ void startup_kernel(void) 


	/* vmlinux decompression is done, shrink reserved low memory */

	physmem_reserve(RR_DECOMPRESSOR, 0, (unsigned long)_decompressor_end);

	amode31_lma = vmlinux.default_lma - vmlinux.amode31_size;

	if (kaslr_enabled())

		amode31_lma = randomize_within_range(vmlinux.amode31_size, PAGE_SIZE, 0, SZ_2G);

	amode31_lma = amode31_lma ?: vmlinux.default_lma - vmlinux.amode31_size;

	physmem_reserve(RR_AMODE31, amode31_lma, vmlinux.amode31_size);



	/*