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arm64/kernel: kaslr: drop special Image placement logic

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Now that the early kernel mapping logic can tolerate placements of
Image that cross swapper table boundaries, we can remove the logic
that adjusts the offset if the dice roll produced an offset that
puts the kernel right on top of one.

Reviewed-by: Steve Capper <steve.capper@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Ard Biesheuvel 2018-01-17 16:11:27 +00:00 committed by Will Deacon
parent 532826f371
commit 6141ac1c27
1 changed files with 0 additions and 15 deletions
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15
arch/arm64/kernel/kaslr.c
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@ -128,21 +128,6 @@ u64 __init kaslr_early_init(u64 dt_phys)
/* use the top 16 bits to randomize the linear region */ /* use the top 16 bits to randomize the linear region */
memstart_offset_seed = seed >> 48; memstart_offset_seed = seed >> 48;
/*
* The kernel Image should not extend across a 1GB/32MB/512MB alignment
* boundary (for 4KB/16KB/64KB granule kernels, respectively). If this
* 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
* account, given that the physical placement is controlled by
* the loader, and will not change as a result of the virtual
* mapping we choose.
*/
if ((((u64)_text + offset) >> SWAPPER_TABLE_SHIFT) !=
(((u64)_end + offset) >> SWAPPER_TABLE_SHIFT))
offset = round_down(offset, 1 << SWAPPER_TABLE_SHIFT);
if (IS_ENABLED(CONFIG_KASAN)) if (IS_ENABLED(CONFIG_KASAN))
/* /*
* KASAN does not expect the module region to intersect the * KASAN does not expect the module region to intersect the