diff options
| author | Ard Biesheuvel <ardb@kernel.org> | 2022-06-24 17:06:33 +0200 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2022-06-24 17:18:09 +0100 |
| commit | e8d13cced5c5038cc93de9561cf2cb4f22205061 (patch) | |
| tree | 7277fb3e279b3243224508328f57790bd72b32dd /arch/arm64/include | |
| parent | 0d9b1ffefabee93727bae68201593fac80a79002 (diff) | |
arm64: head: move assignment of idmap_t0sz to C code
Setting idmap_t0sz involves fiddling with the caches if done with the
MMU off. Since we will be creating an initial ID map with the MMU and
caches off, and the permanent ID map with the MMU and caches on, let's
move this assignment of idmap_t0sz out of the startup code, and replace
it with a macro that simply issues the three instructions needed to
calculate the value wherever it is needed before the MMU is turned on.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20220624150651.1358849-4-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/include')
| -rw-r--r-- | arch/arm64/include/asm/assembler.h | 14 | ||||
| -rw-r--r-- | arch/arm64/include/asm/mmu_context.h | 2 |
2 files changed, 15 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h index 8c5a61aeaf8e..9468f45c07a6 100644 --- a/arch/arm64/include/asm/assembler.h +++ b/arch/arm64/include/asm/assembler.h @@ -360,6 +360,20 @@ alternative_cb_end .endm /* + * idmap_get_t0sz - get the T0SZ value needed to cover the ID map + * + * Calculate the maximum allowed value for TCR_EL1.T0SZ so that the + * entire ID map region can be mapped. As T0SZ == (64 - #bits used), + * this number conveniently equals the number of leading zeroes in + * the physical address of _end. + */ + .macro idmap_get_t0sz, reg + adrp \reg, _end + orr \reg, \reg, #(1 << VA_BITS_MIN) - 1 + clz \reg, \reg + .endm + +/* * tcr_compute_pa_size - set TCR.(I)PS to the highest supported * ID_AA64MMFR0_EL1.PARange value * diff --git a/arch/arm64/include/asm/mmu_context.h b/arch/arm64/include/asm/mmu_context.h index 6770667b34a3..6ac0086ebb1a 100644 --- a/arch/arm64/include/asm/mmu_context.h +++ b/arch/arm64/include/asm/mmu_context.h @@ -60,7 +60,7 @@ static inline void cpu_switch_mm(pgd_t *pgd, struct mm_struct *mm) * TCR_T0SZ(VA_BITS), unless system RAM is positioned very high in * physical memory, in which case it will be smaller. */ -extern u64 idmap_t0sz; +extern int idmap_t0sz; extern u64 idmap_ptrs_per_pgd; /* |