66673099f7
The RISC-V port copies the PGD table from init_mm/swapper_pg_dir to all userland page tables, which means that if the PGD level table is changed, other page tables has to be updated as well. Instead of having the PGD changes ripple out to all tables, the synchronization can be avoided by pre-allocating the PGD entries/pages at boot, avoiding the synchronization all together. This is currently done for the bpf/modules, and vmalloc PGD regions. Extend this scheme for the PGD regions touched by memory hotplugging. Prepare the RISC-V port for memory hotplug by pre-allocate vmemmap/direct map/kasan entries at the PGD level. This will roughly waste ~128 (plus 32 if KASAN is enabled) worth of 4K pages when memory hotplugging is enabled in the kernel configuration. Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com> Signed-off-by: Björn Töpel <bjorn@rivosinc.com> Link: https://lore.kernel.org/r/20240605114100.315918-3-bjorn@kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
46 lines
1.6 KiB
C
46 lines
1.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/* Copyright (C) 2019 Andes Technology Corporation */
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#ifndef __ASM_KASAN_H
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#define __ASM_KASAN_H
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#ifndef __ASSEMBLY__
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/*
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* The following comment was copied from arm64:
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* KASAN_SHADOW_START: beginning of the kernel virtual addresses.
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* KASAN_SHADOW_END: KASAN_SHADOW_START + 1/N of kernel virtual addresses,
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* where N = (1 << KASAN_SHADOW_SCALE_SHIFT).
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*
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* KASAN_SHADOW_OFFSET:
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* This value is used to map an address to the corresponding shadow
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* address by the following formula:
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* shadow_addr = (address >> KASAN_SHADOW_SCALE_SHIFT) + KASAN_SHADOW_OFFSET
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*
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* (1 << (64 - KASAN_SHADOW_SCALE_SHIFT)) shadow addresses that lie in range
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* [KASAN_SHADOW_OFFSET, KASAN_SHADOW_END) cover all 64-bits of virtual
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* addresses. So KASAN_SHADOW_OFFSET should satisfy the following equation:
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* KASAN_SHADOW_OFFSET = KASAN_SHADOW_END -
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* (1ULL << (64 - KASAN_SHADOW_SCALE_SHIFT))
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*/
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#define KASAN_SHADOW_SCALE_SHIFT 3
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#define KASAN_SHADOW_SIZE (UL(1) << ((VA_BITS - 1) - KASAN_SHADOW_SCALE_SHIFT))
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/*
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* Depending on the size of the virtual address space, the region may not be
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* aligned on PGDIR_SIZE, so force its alignment to ease its population.
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*/
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#define KASAN_SHADOW_START ((KASAN_SHADOW_END - KASAN_SHADOW_SIZE) & PGDIR_MASK)
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#define KASAN_SHADOW_END MODULES_LOWEST_VADDR
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#ifdef CONFIG_KASAN
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#define KASAN_SHADOW_OFFSET _AC(CONFIG_KASAN_SHADOW_OFFSET, UL)
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void kasan_init(void);
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asmlinkage void kasan_early_init(void);
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void kasan_swapper_init(void);
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#endif
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#endif
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#endif /* __ASM_KASAN_H */
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