dd006da216
The page size and the number of translation levels, and hence the supported virtual address range, are build-time configurables on arm64 whose optimal values are use case dependent. However, in the current implementation, if the system's RAM is located at a very high offset, the virtual address range needs to reflect that merely because the identity mapping, which is only used to enable or disable the MMU, requires the extended virtual range to map the physical memory at an equal virtual offset. This patch relaxes that requirement, by increasing the number of translation levels for the identity mapping only, and only when actually needed, i.e., when system RAM's offset is found to be out of reach at runtime. Tested-by: Laura Abbott <lauraa@codeaurora.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Tested-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
65 lines
1.8 KiB
ArmAsm
65 lines
1.8 KiB
ArmAsm
/*
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* Based on arch/arm/mm/proc-macros.S
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*
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* Copyright (C) 2012 ARM Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <asm/asm-offsets.h>
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#include <asm/thread_info.h>
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/*
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* vma_vm_mm - get mm pointer from vma pointer (vma->vm_mm)
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*/
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.macro vma_vm_mm, rd, rn
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ldr \rd, [\rn, #VMA_VM_MM]
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.endm
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/*
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* mmid - get context id from mm pointer (mm->context.id)
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*/
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.macro mmid, rd, rn
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ldr \rd, [\rn, #MM_CONTEXT_ID]
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.endm
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/*
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* dcache_line_size - get the minimum D-cache line size from the CTR register.
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*/
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.macro dcache_line_size, reg, tmp
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mrs \tmp, ctr_el0 // read CTR
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ubfm \tmp, \tmp, #16, #19 // cache line size encoding
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mov \reg, #4 // bytes per word
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lsl \reg, \reg, \tmp // actual cache line size
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.endm
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/*
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* icache_line_size - get the minimum I-cache line size from the CTR register.
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*/
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.macro icache_line_size, reg, tmp
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mrs \tmp, ctr_el0 // read CTR
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and \tmp, \tmp, #0xf // cache line size encoding
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mov \reg, #4 // bytes per word
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lsl \reg, \reg, \tmp // actual cache line size
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.endm
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/*
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* tcr_set_idmap_t0sz - update TCR.T0SZ so that we can load the ID map
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*/
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.macro tcr_set_idmap_t0sz, valreg, tmpreg
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#ifndef CONFIG_ARM64_VA_BITS_48
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ldr_l \tmpreg, idmap_t0sz
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bfi \valreg, \tmpreg, #TCR_T0SZ_OFFSET, #TCR_TxSZ_WIDTH
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#endif
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.endm
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