diff options
| author | Youling Tang <tangyouling@loongson.cn> | 2023-02-25 10:52:56 +0300 |
|---|---|---|
| committer | Huacai Chen <chenhuacai@loongson.cn> | 2023-02-25 17:12:17 +0300 |
| commit | e5f02b51fa0cb785e352e77271a65e96051b789b (patch) | |
| tree | 843d66d45eec2f69de38952774c747ed29adf065 /arch/loongarch/kernel/head.S | |
| parent | d8da19fbdedd5852592fbba18a7348e3f09500e6 (diff) | |
| download | linux-e5f02b51fa0cb785e352e77271a65e96051b789b.tar.xz | |
LoongArch: Add support for kernel address space layout randomization (KASLR)
This patch adds support for relocating the kernel to a random address.
Entropy is derived from the banner, which will change every build and
random_get_entropy() which should provide additional runtime entropy.
The kernel is relocated by up to RANDOMIZE_BASE_MAX_OFFSET bytes from
its link address. Because relocation happens so early during the kernel
booting, the amount of physical memory has not yet been determined. This
means the only way to limit relocation within the available memory is
via Kconfig. So we limit the maximum value of RANDOMIZE_BASE_MAX_OFFSET
to 256M (0x10000000) because our memory layout has many holes.
Signed-off-by: Youling Tang <tangyouling@loongson.cn>
Signed-off-by: Xi Ruoyao <xry111@xry111.site> # Fix compiler warnings
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Diffstat (limited to 'arch/loongarch/kernel/head.S')
| -rw-r--r-- | arch/loongarch/kernel/head.S | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/loongarch/kernel/head.S b/arch/loongarch/kernel/head.S index c5c3ec2b819a..1d35becc01ee 100644 --- a/arch/loongarch/kernel/head.S +++ b/arch/loongarch/kernel/head.S @@ -87,7 +87,20 @@ SYM_CODE_START(kernel_entry) # kernel entry point set_saved_sp sp, t0, t1 #ifdef CONFIG_RELOCATABLE + bl relocate_kernel + +#ifdef CONFIG_RANDOMIZE_BASE + /* Repoint the sp into the new kernel */ + PTR_LI sp, (_THREAD_SIZE - PT_SIZE) + PTR_ADD sp, sp, tp + set_saved_sp sp, t0, t1 +#endif + + /* relocate_kernel() returns the new kernel entry point */ + jr a0 + ASM_BUG() + #endif bl start_kernel |