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| author | Catalin Marinas <catalin.marinas@arm.com> | 2017-08-22 16:39:00 +0200 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2017-08-22 19:15:42 +0200 |
| commit | a067d94d37ed590fd17684d18c3edf52110d305a (patch) | |
| tree | a9a77b734e1d41672784140020add86574b48e08 | |
| parent | arm64: kaslr: ignore modulo offset when validating virtual displacement (diff) | |
| download | linux-a067d94d37ed590fd17684d18c3edf52110d305a.tar.xz linux-a067d94d37ed590fd17684d18c3edf52110d305a.zip | |
arm64: kaslr: Adjust the offset to avoid Image across alignment boundary
With 16KB pages and a kernel Image larger than 16MB, the current
kaslr_early_init() logic for avoiding mappings across swapper table
boundaries fails since increasing the offset by kimg_sz just moves the
problem to the next boundary.
This patch rounds the offset down to (1 << SWAPPER_TABLE_SHIFT) if the
Image crosses a PMD_SIZE boundary.
Fixes: afd0e5a87670 ("arm64: kaslr: Fix up the kernel image alignment")
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Neeraj Upadhyay <neeraju@codeaurora.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
| -rw-r--r-- | arch/arm64/kernel/kaslr.c | 10 |
1 files changed, 3 insertions, 7 deletions
diff --git a/arch/arm64/kernel/kaslr.c b/arch/arm64/kernel/kaslr.c index 1d95c204186b..47080c49cc7e 100644 --- a/arch/arm64/kernel/kaslr.c +++ b/arch/arm64/kernel/kaslr.c @@ -131,8 +131,7 @@ u64 __init kaslr_early_init(u64 dt_phys) /* * The kernel Image should not extend across a 1GB/32MB/512MB alignment * boundary (for 4KB/16KB/64KB granule kernels, respectively). If this - * happens, increase the KASLR offset by the size of the kernel image - * rounded up by SWAPPER_BLOCK_SIZE. + * happens, round down the KASLR offset by (1 << SWAPPER_TABLE_SHIFT). * * NOTE: The references to _text and _end below will already take the * modulo offset (the physical displacement modulo 2 MB) into @@ -141,11 +140,8 @@ u64 __init kaslr_early_init(u64 dt_phys) * mapping we choose. */ if ((((u64)_text + offset) >> SWAPPER_TABLE_SHIFT) != - (((u64)_end + offset) >> SWAPPER_TABLE_SHIFT)) { - u64 kimg_sz = _end - _text; - offset = (offset + round_up(kimg_sz, SWAPPER_BLOCK_SIZE)) - & mask; - } + (((u64)_end + offset) >> SWAPPER_TABLE_SHIFT)) + offset = round_down(offset, 1 << SWAPPER_TABLE_SHIFT); if (IS_ENABLED(CONFIG_KASAN)) /* |