diff options
| author | Mark Rutland <mark.rutland@arm.com> | 2014-06-24 16:51:37 +0100 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2014-07-10 12:36:58 +0100 |
| commit | da57a369d3bc5cd61db90f7e9555840381db9b09 (patch) | |
| tree | 6e2e032c24d4b36e792e91984191752f527baf09 /arch/arm64/kernel | |
| parent | a2c1d73b94ed49f5fac12e95052d7b140783f800 (diff) | |
arm64: Enable TEXT_OFFSET fuzzing
The arm64 Image header contains a text_offset field which bootloaders
are supposed to read to determine the offset (from a 2MB aligned "start
of memory" per booting.txt) at which to load the kernel. The offset is
not well respected by bootloaders at present, and due to the lack of
variation there is little incentive to support it. This is unfortunate
for the sake of future kernels where we may wish to vary the text offset
(even zeroing it).
This patch adds options to arm64 to enable fuzz-testing of text_offset.
CONFIG_ARM64_RANDOMIZE_TEXT_OFFSET forces the text offset to a random
16-byte aligned value value in the range [0..2MB) upon a build of the
kernel. It is recommended that distribution kernels enable randomization
to test bootloaders such that any compliance issues can be fixed early.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Tom Rini <trini@ti.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel')
| -rw-r--r-- | arch/arm64/kernel/head.S | 8 | ||||
| -rw-r--r-- | arch/arm64/kernel/vmlinux.lds.S | 5 |
2 files changed, 11 insertions, 2 deletions
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index 3ba0fc02c0de..69dafe9621fd 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -37,8 +37,12 @@ #define KERNEL_RAM_VADDR (PAGE_OFFSET + TEXT_OFFSET) -#if (KERNEL_RAM_VADDR & 0xfffff) != 0x80000 -#error KERNEL_RAM_VADDR must start at 0xXXX80000 +#if (TEXT_OFFSET & 0xf) != 0 +#error TEXT_OFFSET must be at least 16B aligned +#elif (PAGE_OFFSET & 0xfffff) != 0 +#error PAGE_OFFSET must be at least 2MB aligned +#elif TEXT_OFFSET > 0xfffff +#error TEXT_OFFSET must be less than 2MB #endif .macro pgtbl, ttb0, ttb1, virt_to_phys diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S index a814768ae148..97f0c0429dfa 100644 --- a/arch/arm64/kernel/vmlinux.lds.S +++ b/arch/arm64/kernel/vmlinux.lds.S @@ -125,3 +125,8 @@ SECTIONS */ ASSERT(((__hyp_idmap_text_start + PAGE_SIZE) > __hyp_idmap_text_end), "HYP init code too big") + +/* + * If padding is applied before .head.text, virt<->phys conversions will fail. + */ +ASSERT(_text == (PAGE_OFFSET + TEXT_OFFSET), "HEAD is misaligned") |