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| author | Vasily Gorbik <gor@linux.ibm.com> | 2023-03-15 13:54:14 +0100 |
|---|---|---|
| committer | Vasily Gorbik <gor@linux.ibm.com> | 2023-04-13 17:36:27 +0200 |
| commit | b3e0423c4e76b19f04799e01b6443949f5fecbbc (patch) | |
| tree | d49a6964ceca822d83bf54d8a93dcf409238828b /arch/s390/boot | |
| parent | s390/kaslr: generalize and improve random base distribution (diff) | |
| download | linux-b3e0423c4e76b19f04799e01b6443949f5fecbbc.tar.xz linux-b3e0423c4e76b19f04799e01b6443949f5fecbbc.zip | |
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: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'arch/s390/boot')
| -rw-r--r-- | arch/s390/boot/startup.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/s390/boot/startup.c b/arch/s390/boot/startup.c index 638a6cf8a075..64bd7ac3e35d 100644 --- a/arch/s390/boot/startup.c +++ b/arch/s390/boot/startup.c @@ -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); /* |