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| author | Ard Biesheuvel <ardb@kernel.org> | 2024-02-14 15:29:05 +0300 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2024-02-16 15:42:34 +0300 |
| commit | e6128a8e523cfa8f46a1501e6432c37523b47bdf (patch) | |
| tree | 45e0892c264c5ff1e1972f8a4423051c34dcaa8b /arch/arm64/include | |
| parent | 97a6f43bb049e64b9913c50c7530e13d78e205d4 (diff) | |
| download | linux-e6128a8e523cfa8f46a1501e6432c37523b47bdf.tar.xz | |
arm64: mm: Use 48-bit virtual addressing for the permanent ID map
Even though we support loading kernels anywhere in 48-bit addressable
physical memory, we create the ID maps based on the number of levels
that we happened to configure for the kernel VA and user VA spaces.
The reason for this is that the PGD/PUD/PMD based classification of
translation levels, along with the associated folding when the number of
levels is less than 5, does not permit creating a page table hierarchy
of a set number of levels. This means that, for instance, on 39-bit VA
kernels we need to configure an additional level above PGD level on the
fly, and 36-bit VA kernels still only support 47-bit virtual addressing
with this trick applied.
Now that we have a separate helper to populate page table hierarchies
that does not define the levels in terms of PUDS/PMDS/etc at all, let's
reuse it to create the permanent ID map with a fixed VA size of 48 bits.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20240214122845.2033971-64-ardb+git@google.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/include')
| -rw-r--r-- | arch/arm64/include/asm/kernel-pgtable.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/kernel-pgtable.h b/arch/arm64/include/asm/kernel-pgtable.h index 0631604995ee..742a4b2778f7 100644 --- a/arch/arm64/include/asm/kernel-pgtable.h +++ b/arch/arm64/include/asm/kernel-pgtable.h @@ -35,6 +35,9 @@ #define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS) #endif +#define IDMAP_VA_BITS 48 +#define IDMAP_LEVELS ARM64_HW_PGTABLE_LEVELS(IDMAP_VA_BITS) +#define IDMAP_ROOT_LEVEL (4 - IDMAP_LEVELS) /* * A relocatable kernel may execute from an address that differs from the one at |