Adding "kalsr-seed" to dtb enables triggering kaslr, or kernel virtual address randomization, at secondary kernel boot. We always do this as it wll have no harm on kaslr-incapable kernel.
We don't have any "switch" to turn off this feature directly, but still can suppress it by passing "nokaslr" as a kernel boot argument. Signed-off-by: AKASHI Takahiro <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Will Deacon <[email protected]> --- arch/arm64/kernel/machine_kexec_file.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c index ec674f4d267c..762f9102899c 100644 --- a/arch/arm64/kernel/machine_kexec_file.c +++ b/arch/arm64/kernel/machine_kexec_file.c @@ -16,6 +16,7 @@ #include <linux/libfdt.h> #include <linux/memblock.h> #include <linux/of_fdt.h> +#include <linux/random.h> #include <linux/types.h> #include <linux/vmalloc.h> #include <asm/byteorder.h> @@ -246,6 +247,12 @@ static int setup_dtb(struct kimage *image, goto out_err; } + /* add kaslr-seed */ + get_random_bytes(&value, sizeof(value)); + ret = fdt_setprop(buf, nodeoffset, "kaslr-seed", &value, sizeof(value)); + if (ret) + goto out_err; + /* trim a buffer */ fdt_pack(buf); *dtb_buf = buf; -- 2.17.0
